diff --git a/CHANGELOG.md b/CHANGELOG.md
index e71797f25f..f2478cabb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,10 @@
 
 # 12.0.0-alpha.3 (Unreleased)
 
+#### :bug: Bug fix
+
+- Revert Throws an instance of JavaScript's `new Error()` and adds the extension payload for `cause` option introduced in https://github.com/rescript-lang/rescript-compiler/pull/6611. https://github.com/rescript-lang/rescript-compiler/pull/7016
+
 # 12.0.0-alpha.2
 
 #### :rocket: New Feature
@@ -2623,4 +2627,4 @@ Features:
 
 # 1.0.0
 
-Initial release
\ No newline at end of file
+Initial release
diff --git a/jscomp/core/js_dump.ml b/jscomp/core/js_dump.ml
index 2e2a1d3aef..9a4fee77d2 100644
--- a/jscomp/core/js_dump.ml
+++ b/jscomp/core/js_dump.ml
@@ -97,11 +97,8 @@ type cxt = Ext_pp_scope.t
 let semi f = P.string f L.semi
 let comma f = P.string f L.comma
 
-let new_error name cause =
-  E.new_ (E.js_global Js_dump_lit.error) [ name; cause ]
-
 let exn_block_as_obj ~(stack : bool) (el : J.expression list) (ext : J.tag_info)
-    : J.expression =
+    : J.expression_desc =
   let field_name =
     match ext with
     | Blk_extension -> (
@@ -111,29 +108,12 @@ let exn_block_as_obj ~(stack : bool) (el : J.expression list) (ext : J.tag_info)
         fun i -> match i with 0 -> Literals.exception_id | i -> ss.(i - 1))
     | _ -> assert false
   in
-    let cause =
-    {
-      J.expression_desc =
-        Object (List.mapi (fun i e -> (Js_op.Lit (field_name i), e)) el);
-      comment = None;
-    }
-  in
-   if stack then
-      new_error (List.hd el)
-        {
-          J.expression_desc = Object [ (Lit Js_dump_lit.cause, cause) ];
-          comment = None;
-        }
-    else cause
-
-let exn_ref_as_obj e : J.expression =
-  let cause = { J.expression_desc = e; comment = None; } in
-  new_error
-    (E.record_access cause Js_dump_lit.exception_id 0l)
-    {
-      J.expression_desc = Object [ (Lit Js_dump_lit.cause, cause) ];
-      comment = None;
-    }
+  Object
+    (if stack then
+     Ext_list.mapi_append el
+       (fun i e -> (Js_op.Lit (field_name i), e))
+       [ (Js_op.Lit "Error", E.new_ (E.js_global "Error") []) ]
+    else Ext_list.mapi el (fun i e -> (Js_op.Lit (field_name i), e)))
 
 let rec iter_lst cxt (f : P.t) ls element inter =
   match ls with
@@ -777,7 +757,7 @@ and expression_desc cxt ~(level : int) f x : cxt =
                ])
       | _ -> assert false)
   | Caml_block (el, _, _, ((Blk_extension | Blk_record_ext _) as ext)) ->
-      expression cxt ~level f (exn_block_as_obj ~stack:false el ext)
+      expression_desc cxt ~level f (exn_block_as_obj ~stack:false el ext)
   | Caml_block (el, _, tag, Blk_record_inlined p) ->
       let untagged = Ast_untagged_variants.process_untagged p.attrs in
       let objs =
@@ -1239,8 +1219,8 @@ and statement_desc top cxt f (s : J.statement_desc) : cxt =
       let e =
         match e.expression_desc with
         | Caml_block (el, _, _, ((Blk_extension | Blk_record_ext _) as ext)) ->
-            { e with expression_desc = (exn_block_as_obj ~stack:true el ext).expression_desc }
-        | exp -> { e with expression_desc = (exn_ref_as_obj exp).expression_desc }
+            { e with expression_desc = exn_block_as_obj ~stack:true el ext }
+        | _ -> e
       in
       P.string f L.throw;
       P.space f;
diff --git a/jscomp/core/js_dump_lit.ml b/jscomp/core/js_dump_lit.ml
index c341c7f1c6..fd53d77449 100644
--- a/jscomp/core/js_dump_lit.ml
+++ b/jscomp/core/js_dump_lit.ml
@@ -168,9 +168,3 @@ let block_variant = "variant"
 let block_simple_variant = "simpleVariant"
 
 let case = "case"
-
-let cause = "cause"
-
-let error = "Error"
-
-let exception_id = "RE_EXN_ID"
diff --git a/jscomp/core/js_exp_make.ml b/jscomp/core/js_exp_make.ml
index ebbd80d281..128e2daea0 100644
--- a/jscomp/core/js_exp_make.ml
+++ b/jscomp/core/js_exp_make.ml
@@ -416,7 +416,7 @@ let poly_var_value_access (e : t) =
         comment = None;
       }
 
-let extension_access (e : t) ?name (pos : int32) : t =
+let extension_access (e : t) name (pos : int32) : t =
   match e.expression_desc with
   | Array (l, _) (* Float i -- should not appear here *)
   | Caml_block (l, _, _, _)
diff --git a/jscomp/core/js_exp_make.mli b/jscomp/core/js_exp_make.mli
index 2e1cd072bb..f7d36bcc56 100644
--- a/jscomp/core/js_exp_make.mli
+++ b/jscomp/core/js_exp_make.mli
@@ -170,7 +170,7 @@ val variant_access : t -> int32 -> t
 
 val cons_access : t -> int32 -> t
 
-val extension_access : t -> ?name:string -> Int32.t -> t
+val extension_access : t -> string option -> Int32.t -> t
 
 val record_assign : t -> int32 -> string -> t -> t
 
diff --git a/jscomp/core/js_of_lam_block.ml b/jscomp/core/js_of_lam_block.ml
index 5bcb8ff9ef..b665462d80 100644
--- a/jscomp/core/js_of_lam_block.ml
+++ b/jscomp/core/js_of_lam_block.ml
@@ -38,8 +38,8 @@ let field (field_info : Lam_compat.field_dbg_info) e (i : int32) =
         e i
   | Fld_poly_var_content -> E.poly_var_value_access e
   | Fld_poly_var_tag -> E.poly_var_tag_access e
-  | Fld_record_extension { name } -> E.extension_access e ~name i
-  | Fld_extension -> E.extension_access e i
+  | Fld_record_extension { name } -> E.extension_access e (Some name) i
+  | Fld_extension -> E.extension_access e None i
   | Fld_variant -> E.variant_access e i
   | Fld_cons -> E.cons_access e i
   | Fld_record_inline { name } -> E.inline_record_access e name i
diff --git a/jscomp/core/lam_convert.ml b/jscomp/core/lam_convert.ml
index 442dfe4ab1..adc645747f 100644
--- a/jscomp/core/lam_convert.ml
+++ b/jscomp/core/lam_convert.ml
@@ -22,17 +22,14 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)
 
+let caml_id_field_info : Lambda.field_dbg_info =
+  Fld_record { name = Literals.exception_id; mutable_flag = Immutable }
+
+let lam_caml_id : Lam_primitive.t = Pfield (0, caml_id_field_info)
 let prim = Lam.prim
 
-let lam_extension_id =
-  let lam_caml_id : Lam_primitive.t =
-    let caml_id_field_info : Lambda.field_dbg_info =
-      Fld_record { name = Js_dump_lit.exception_id; mutable_flag = Immutable }
-    in
-    Pfield (0, caml_id_field_info)
-  in
-  fun loc (head : Lam.t) ->
-    prim ~primitive:lam_caml_id ~args:[ head ] loc
+let lam_extension_id loc (head : Lam.t) =
+  prim ~primitive:lam_caml_id ~args:[ head ] loc
 
 let lazy_block_info : Lam_tag_info.t =
   Blk_record
diff --git a/jscomp/runtime/caml_format.res b/jscomp/runtime/caml_format.res
index 6fbee88afa..9705f3a482 100644
--- a/jscomp/runtime/caml_format.res
+++ b/jscomp/runtime/caml_format.res
@@ -709,7 +709,7 @@ let float_of_string: (string, exn) => float = %raw(`function(s,exn){
         return Infinity;
     if (/^-inf(inity)?$/i.test(s))
         return -Infinity;
-    throw new Error(exn.RE_EXN_ID, { cause: exn });;
+    throw exn;
 }
 `)
 
diff --git a/jscomp/runtime/caml_js_exceptions.res b/jscomp/runtime/caml_js_exceptions.res
index ea41d4e3df..6ef72df7c5 100644
--- a/jscomp/runtime/caml_js_exceptions.res
+++ b/jscomp/runtime/caml_js_exceptions.res
@@ -29,8 +29,8 @@ type js_error = {cause: exn}
    [Error] is defined here 
 */
 let internalToOCamlException = (e: unknown) =>
-  if Caml_exceptions.is_extension((Obj.magic(e): js_error).cause) {
-    (Obj.magic(e): js_error).cause
+  if Caml_exceptions.is_extension(e) {
+    (Obj.magic(e): exn)
   } else {
     JsError(e)
   }
diff --git a/jscomp/runtime/caml_lexer.res b/jscomp/runtime/caml_lexer.res
index 28b277264c..69f228b58e 100644
--- a/jscomp/runtime/caml_lexer.res
+++ b/jscomp/runtime/caml_lexer.res
@@ -160,7 +160,7 @@ let caml_lex_engine_aux: (
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn })
+                throw exn
             else
                 return lexbuf.lex_last_action;
         }
@@ -308,7 +308,7 @@ let caml_new_lex_engine_aux: (
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn });
+                throw exn;
             else
                 return lexbuf.lex_last_action;
         }
diff --git a/jscomp/test/406_primitive_test.js b/jscomp/test/406_primitive_test.js
index 7292ab1928..f094d9242d 100644
--- a/jscomp/test/406_primitive_test.js
+++ b/jscomp/test/406_primitive_test.js
@@ -34,12 +34,11 @@ function f() {
   try {
     for (let i = 0; i <= 200; ++i) {
       if (i === 10) {
-        throw new Error(A, {
-          cause: {
-            RE_EXN_ID: A,
-            _1: 0
-          }
-        });
+        throw {
+          RE_EXN_ID: A,
+          _1: 0,
+          Error: new Error()
+        };
       }
       
     }
@@ -49,9 +48,7 @@ function f() {
     if (exn.RE_EXN_ID === A) {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/UncurriedExternals.js b/jscomp/test/UncurriedExternals.js
index 5ec20d4073..16c435711e 100644
--- a/jscomp/test/UncurriedExternals.js
+++ b/jscomp/test/UncurriedExternals.js
@@ -4,11 +4,10 @@
 let React = require("react");
 
 function dd() {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let h = sum(1.0, 2.0);
diff --git a/jscomp/test/adt_optimize_test.js b/jscomp/test/adt_optimize_test.js
index 29405a959d..ee9aab3edd 100644
--- a/jscomp/test/adt_optimize_test.js
+++ b/jscomp/test/adt_optimize_test.js
@@ -182,16 +182,15 @@ function f11(x) {
   if (x.TAG === "D") {
     return 1;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "adt_optimize_test.res",
-        202,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "adt_optimize_test.res",
+      202,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 exports.f = f;
diff --git a/jscomp/test/argv_test.js b/jscomp/test/argv_test.js
index d324689acb..727bfd8154 100644
--- a/jscomp/test/argv_test.js
+++ b/jscomp/test/argv_test.js
@@ -50,29 +50,27 @@ Arg.parse_argv(undefined, [
 ], arg_spec, anno_fun, usage_msg);
 
 if (compile.contents !== true) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "argv_test.res",
-        14,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "argv_test.res",
+      14,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (test.contents !== false) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "argv_test.res",
-        15,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "argv_test.res",
+      15,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 exports.anno_fun = anno_fun;
diff --git a/jscomp/test/arith_parser.js b/jscomp/test/arith_parser.js
index 7520e20b28..a7e951781d 100644
--- a/jscomp/test/arith_parser.js
+++ b/jscomp/test/arith_parser.js
@@ -140,12 +140,11 @@ let yynames_block = "\
 
 let yyact = [
   param => {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "parser"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "parser",
+      Error: new Error()
+    };
   },
   __caml_parser_env => Parsing.peek_val(__caml_parser_env, 1),
   __caml_parser_env => {
@@ -207,12 +206,11 @@ let yyact = [
   },
   __caml_parser_env => Parsing.peek_val(__caml_parser_env, 1),
   __caml_parser_env => {
-    throw new Error(Parsing.YYexit, {
-      cause: {
-        RE_EXN_ID: Parsing.YYexit,
-        _1: Parsing.peek_val(__caml_parser_env, 0)
-      }
-    });
+    throw {
+      RE_EXN_ID: Parsing.YYexit,
+      _1: Parsing.peek_val(__caml_parser_env, 0),
+      Error: new Error()
+    };
   }
 ];
 
diff --git a/jscomp/test/arity_infer.js b/jscomp/test/arity_infer.js
index 18da9fe57b..0e7fd13815 100644
--- a/jscomp/test/arity_infer.js
+++ b/jscomp/test/arity_infer.js
@@ -7,21 +7,19 @@ function f0(x) {
   if (x > 3) {
     tmp = x => x + 1 | 0;
   } else {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   return tmp(3);
 }
 
 function f1(x) {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
   return undefined(x);
 }
 
@@ -41,11 +39,10 @@ function f3(x) {
       tmp = x => x + 4 | 0;
       break;
     default:
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
   }
   return tmp(3);
 }
diff --git a/jscomp/test/array_safe_get.js b/jscomp/test/array_safe_get.js
index ce8a0437bf..8a669d3822 100644
--- a/jscomp/test/array_safe_get.js
+++ b/jscomp/test/array_safe_get.js
@@ -19,9 +19,7 @@ try {
     console.log(msg._1);
     y = 0;
   } else {
-    throw new Error(msg.RE_EXN_ID, {
-      cause: msg
-    });
+    throw msg;
   }
 }
 
diff --git a/jscomp/test/array_test.js b/jscomp/test/array_test.js
index f84793a3f5..6a896b1c6b 100644
--- a/jscomp/test/array_test.js
+++ b/jscomp/test/array_test.js
@@ -20,11 +20,10 @@ function starts_with(xs, prefix, p) {
   try {
     for (let i = 0; i < len2; ++i) {
       if (!p(Caml_array.get(xs, i), Caml_array.get(prefix, i))) {
-        throw new Error(H, {
-          cause: {
-            RE_EXN_ID: H
-          }
-        });
+        throw {
+          RE_EXN_ID: H,
+          Error: new Error()
+        };
       }
       
     }
@@ -34,9 +33,7 @@ function starts_with(xs, prefix, p) {
     if (exn.RE_EXN_ID === H) {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/bb.js b/jscomp/test/bb.js
index ad4c90bb11..18f51ea211 100644
--- a/jscomp/test/bb.js
+++ b/jscomp/test/bb.js
@@ -21,16 +21,15 @@ function ff(x) {
     case "c" :
       return "c";
     default:
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "bb.res",
-            13,
-            9
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "bb.res",
+          13,
+          9
+        ],
+        Error: new Error()
+      };
   }
 }
 
@@ -47,16 +46,15 @@ function test(x) {
       match = "c";
       break;
     default:
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "bb.res",
-            21,
-            9
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "bb.res",
+          21,
+          9
+        ],
+        Error: new Error()
+      };
   }
   if (match === "b") {
     return "b";
diff --git a/jscomp/test/bdd.js b/jscomp/test/bdd.js
index a7b4f929b5..ac5c277765 100644
--- a/jscomp/test/bdd.js
+++ b/jscomp/test/bdd.js
@@ -67,27 +67,25 @@ function resize(newSize) {
       let n = bucket.hd;
       if (typeof n !== "object") {
         if (n === "One") {
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "bdd.res",
-                60,
-                13
-              ]
-            }
-          });
-        }
-        throw new Error("Assert_failure", {
-          cause: {
+          throw {
             RE_EXN_ID: "Assert_failure",
             _1: [
               "bdd.res",
               60,
               13
-            ]
-          }
-        });
+            ],
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "bdd.res",
+            60,
+            13
+          ],
+          Error: new Error()
+        };
       } else {
         let ind = hashVal(getId(n._0), getId(n._3), n._1) & newSz_1;
         Caml_array.set(newArr, ind, {
@@ -145,27 +143,25 @@ function mkNode(low, v, high) {
       let n = b.hd;
       if (typeof n !== "object") {
         if (n === "One") {
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "bdd.res",
-                121,
-                15
-              ]
-            }
-          });
-        }
-        throw new Error("Assert_failure", {
-          cause: {
+          throw {
             RE_EXN_ID: "Assert_failure",
             _1: [
               "bdd.res",
               121,
               15
-            ]
-          }
-        });
+            ],
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "bdd.res",
+            121,
+            15
+          ],
+          Error: new Error()
+        };
       } else {
         if (v === n._1 && idl === getId(n._0) && idh === getId(n._3)) {
           return n;
@@ -402,16 +398,15 @@ function main() {
   if (succeeded) {
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bdd.res",
-        301,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bdd.res",
+      301,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 main();
diff --git a/jscomp/test/bench.js b/jscomp/test/bench.js
index 8223ef2471..aa70b76e77 100644
--- a/jscomp/test/bench.js
+++ b/jscomp/test/bench.js
@@ -23,12 +23,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f$1(0));
   for (let i = 1; i < l; ++i) {
diff --git a/jscomp/test/big_polyvar_test.js b/jscomp/test/big_polyvar_test.js
index 3cf61f097f..20c276f20f 100644
--- a/jscomp/test/big_polyvar_test.js
+++ b/jscomp/test/big_polyvar_test.js
@@ -25,7816 +25,7215 @@ function eq(x, y) {
 }
 
 if ("variant0" !== "variant0") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        314,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      314,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant1" !== "variant1") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        315,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      315,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant2" !== "variant2") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        316,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      316,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant3" !== "variant3") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        317,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      317,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant4" !== "variant4") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        318,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      318,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant5" !== "variant5") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        319,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      319,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant6" !== "variant6") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        320,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      320,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant7" !== "variant7") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        321,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      321,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant8" !== "variant8") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        322,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      322,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant9" !== "variant9") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        323,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      323,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant10" !== "variant10") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        324,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      324,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant11" !== "variant11") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        325,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      325,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant12" !== "variant12") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        326,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      326,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant13" !== "variant13") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        327,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      327,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant14" !== "variant14") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        328,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      328,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant15" !== "variant15") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        329,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      329,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant16" !== "variant16") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        330,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      330,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant17" !== "variant17") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        331,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      331,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant18" !== "variant18") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        332,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      332,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant19" !== "variant19") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        333,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      333,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant20" !== "variant20") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        334,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      334,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant21" !== "variant21") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        335,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      335,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant22" !== "variant22") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        336,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      336,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant23" !== "variant23") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        337,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      337,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant24" !== "variant24") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        338,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      338,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant25" !== "variant25") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        339,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      339,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant26" !== "variant26") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        340,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      340,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant27" !== "variant27") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        341,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      341,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant28" !== "variant28") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        342,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      342,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant29" !== "variant29") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        343,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      343,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant30" !== "variant30") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        344,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      344,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant31" !== "variant31") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        345,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      345,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant32" !== "variant32") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        346,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      346,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant33" !== "variant33") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        347,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      347,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant34" !== "variant34") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        348,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      348,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant35" !== "variant35") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        349,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      349,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant36" !== "variant36") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        350,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      350,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant37" !== "variant37") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        351,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      351,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant38" !== "variant38") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        352,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      352,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant39" !== "variant39") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        353,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      353,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant40" !== "variant40") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        354,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      354,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant41" !== "variant41") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        355,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      355,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant42" !== "variant42") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        356,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      356,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant43" !== "variant43") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        357,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      357,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant44" !== "variant44") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        358,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      358,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant45" !== "variant45") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        359,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      359,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant46" !== "variant46") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        360,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      360,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant47" !== "variant47") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        361,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      361,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant48" !== "variant48") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        362,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      362,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant49" !== "variant49") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        363,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      363,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant50" !== "variant50") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        364,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      364,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant51" !== "variant51") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        365,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      365,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant52" !== "variant52") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        366,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      366,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant53" !== "variant53") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        367,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      367,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant54" !== "variant54") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        368,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      368,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant55" !== "variant55") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        369,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      369,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant56" !== "variant56") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        370,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      370,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant57" !== "variant57") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        371,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      371,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant58" !== "variant58") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        372,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      372,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant59" !== "variant59") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        373,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      373,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant60" !== "variant60") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        374,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      374,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant61" !== "variant61") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        375,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      375,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant62" !== "variant62") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        376,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      376,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant63" !== "variant63") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        377,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      377,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant64" !== "variant64") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        378,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      378,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant65" !== "variant65") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        379,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      379,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant66" !== "variant66") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        380,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      380,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant67" !== "variant67") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        381,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      381,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant68" !== "variant68") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        382,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      382,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant69" !== "variant69") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        383,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      383,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant70" !== "variant70") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        384,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      384,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant71" !== "variant71") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        385,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      385,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant72" !== "variant72") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        386,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      386,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant73" !== "variant73") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        387,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      387,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant74" !== "variant74") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        388,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      388,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant75" !== "variant75") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        389,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      389,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant76" !== "variant76") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        390,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      390,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant77" !== "variant77") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        391,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      391,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant78" !== "variant78") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        392,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      392,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant79" !== "variant79") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        393,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      393,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant80" !== "variant80") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        394,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      394,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant81" !== "variant81") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        395,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      395,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant82" !== "variant82") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        396,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      396,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant83" !== "variant83") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        397,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      397,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant84" !== "variant84") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        398,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      398,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant85" !== "variant85") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        399,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      399,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant86" !== "variant86") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        400,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      400,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant87" !== "variant87") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        401,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      401,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant88" !== "variant88") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        402,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      402,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant89" !== "variant89") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        403,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      403,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant90" !== "variant90") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        404,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      404,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant91" !== "variant91") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        405,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      405,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant92" !== "variant92") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        406,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      406,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant93" !== "variant93") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        407,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      407,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant94" !== "variant94") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        408,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      408,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant95" !== "variant95") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        409,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      409,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant96" !== "variant96") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        410,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      410,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant97" !== "variant97") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        411,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      411,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant98" !== "variant98") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        412,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      412,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant99" !== "variant99") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        413,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      413,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant100" !== "variant100") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        414,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      414,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant101" !== "variant101") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        415,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      415,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant102" !== "variant102") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        416,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      416,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant103" !== "variant103") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        417,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      417,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant104" !== "variant104") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        418,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      418,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant105" !== "variant105") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        419,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      419,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant106" !== "variant106") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        420,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      420,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant107" !== "variant107") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        421,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      421,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant108" !== "variant108") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        422,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      422,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant109" !== "variant109") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        423,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      423,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant110" !== "variant110") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        424,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      424,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant111" !== "variant111") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        425,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      425,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant112" !== "variant112") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        426,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      426,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant113" !== "variant113") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        427,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      427,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant114" !== "variant114") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        428,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      428,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant115" !== "variant115") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        429,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      429,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant116" !== "variant116") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        430,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      430,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant117" !== "variant117") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        431,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      431,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant118" !== "variant118") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        432,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      432,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant119" !== "variant119") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        433,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      433,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant120" !== "variant120") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        434,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      434,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant121" !== "variant121") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        435,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      435,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant122" !== "variant122") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        436,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      436,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant123" !== "variant123") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        437,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      437,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant124" !== "variant124") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        438,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      438,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant125" !== "variant125") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        439,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      439,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant126" !== "variant126") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        440,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      440,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant127" !== "variant127") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        441,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      441,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant128" !== "variant128") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        442,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      442,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant129" !== "variant129") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        443,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      443,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant130" !== "variant130") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        444,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      444,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant131" !== "variant131") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        445,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      445,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant132" !== "variant132") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        446,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      446,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant133" !== "variant133") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        447,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      447,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant134" !== "variant134") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        448,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      448,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant135" !== "variant135") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        449,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      449,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant136" !== "variant136") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        450,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      450,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant137" !== "variant137") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        451,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      451,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant138" !== "variant138") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        452,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      452,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant139" !== "variant139") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        453,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      453,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant140" !== "variant140") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        454,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      454,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant141" !== "variant141") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        455,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      455,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant142" !== "variant142") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        456,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      456,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant143" !== "variant143") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        457,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      457,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant144" !== "variant144") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        458,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      458,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant145" !== "variant145") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        459,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      459,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant146" !== "variant146") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        460,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      460,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant147" !== "variant147") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        461,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      461,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant148" !== "variant148") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        462,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      462,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant149" !== "variant149") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        463,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      463,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant150" !== "variant150") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        464,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      464,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant151" !== "variant151") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        465,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      465,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant152" !== "variant152") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        466,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      466,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant153" !== "variant153") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        467,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      467,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant154" !== "variant154") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        468,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      468,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant155" !== "variant155") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        469,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      469,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant156" !== "variant156") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        470,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      470,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant157" !== "variant157") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        471,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      471,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant158" !== "variant158") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        472,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      472,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant159" !== "variant159") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        473,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      473,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant160" !== "variant160") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        474,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      474,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant161" !== "variant161") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        475,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      475,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant162" !== "variant162") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        476,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      476,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant163" !== "variant163") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        477,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      477,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant164" !== "variant164") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        478,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      478,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant165" !== "variant165") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        479,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      479,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant166" !== "variant166") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        480,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      480,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant167" !== "variant167") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        481,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      481,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant168" !== "variant168") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        482,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      482,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant169" !== "variant169") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        483,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      483,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant170" !== "variant170") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        484,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      484,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant171" !== "variant171") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        485,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      485,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant172" !== "variant172") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        486,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      486,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant173" !== "variant173") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        487,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      487,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant174" !== "variant174") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        488,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      488,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant175" !== "variant175") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        489,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      489,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant176" !== "variant176") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        490,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      490,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant177" !== "variant177") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        491,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      491,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant178" !== "variant178") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        492,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      492,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant179" !== "variant179") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        493,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      493,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant180" !== "variant180") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        494,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      494,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant181" !== "variant181") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        495,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      495,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant182" !== "variant182") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        496,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      496,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant183" !== "variant183") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        497,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      497,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant184" !== "variant184") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        498,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      498,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant185" !== "variant185") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        499,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      499,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant186" !== "variant186") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        500,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      500,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant187" !== "variant187") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        501,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      501,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant188" !== "variant188") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        502,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      502,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant189" !== "variant189") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        503,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      503,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant190" !== "variant190") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        504,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      504,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant191" !== "variant191") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        505,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      505,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant192" !== "variant192") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        506,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      506,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant193" !== "variant193") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        507,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      507,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant194" !== "variant194") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        508,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      508,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant195" !== "variant195") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        509,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      509,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant196" !== "variant196") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        510,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      510,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant197" !== "variant197") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        511,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      511,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant198" !== "variant198") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        512,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      512,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant199" !== "variant199") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        513,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      513,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant200" !== "variant200") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        514,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      514,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant201" !== "variant201") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        515,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      515,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant202" !== "variant202") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        516,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      516,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant203" !== "variant203") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        517,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      517,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant204" !== "variant204") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        518,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      518,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant205" !== "variant205") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        519,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      519,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant206" !== "variant206") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        520,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      520,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant207" !== "variant207") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        521,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      521,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant208" !== "variant208") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        522,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      522,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant209" !== "variant209") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        523,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      523,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant210" !== "variant210") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        524,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      524,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant211" !== "variant211") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        525,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      525,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant212" !== "variant212") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        526,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      526,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant213" !== "variant213") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        527,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      527,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant214" !== "variant214") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        528,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      528,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant215" !== "variant215") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        529,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      529,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant216" !== "variant216") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        530,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      530,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant217" !== "variant217") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        531,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      531,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant218" !== "variant218") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        532,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      532,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant219" !== "variant219") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        533,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      533,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant220" !== "variant220") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        534,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      534,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant221" !== "variant221") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        535,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      535,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant222" !== "variant222") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        536,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      536,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant223" !== "variant223") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        537,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      537,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant224" !== "variant224") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        538,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      538,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant225" !== "variant225") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        539,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      539,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant226" !== "variant226") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        540,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      540,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant227" !== "variant227") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        541,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      541,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant228" !== "variant228") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        542,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      542,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant229" !== "variant229") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        543,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      543,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant230" !== "variant230") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        544,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      544,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant231" !== "variant231") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        545,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      545,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant232" !== "variant232") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        546,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      546,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant233" !== "variant233") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        547,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      547,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant234" !== "variant234") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        548,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      548,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant235" !== "variant235") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        549,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      549,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant236" !== "variant236") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        550,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      550,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant237" !== "variant237") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        551,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      551,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant238" !== "variant238") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        552,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      552,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant239" !== "variant239") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        553,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      553,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant240" !== "variant240") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        554,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      554,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant241" !== "variant241") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        555,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      555,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant242" !== "variant242") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        556,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      556,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant243" !== "variant243") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        557,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      557,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant244" !== "variant244") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        558,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      558,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant245" !== "variant245") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        559,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      559,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant246" !== "variant246") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        560,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      560,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant247" !== "variant247") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        561,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      561,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant248" !== "variant248") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        562,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      562,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant249" !== "variant249") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        563,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      563,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant250" !== "variant250") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        564,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      564,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant251" !== "variant251") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        565,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      565,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant252" !== "variant252") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        566,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      566,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant253" !== "variant253") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        567,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      567,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant254" !== "variant254") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        568,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      568,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant255" !== "variant255") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        569,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      569,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant256" !== "variant256") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        570,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      570,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant257" !== "variant257") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        571,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      571,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant258" !== "variant258") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        572,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      572,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant259" !== "variant259") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        573,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      573,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant260" !== "variant260") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        574,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      574,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant261" !== "variant261") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        575,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      575,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant262" !== "variant262") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        576,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      576,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant263" !== "variant263") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        577,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      577,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant264" !== "variant264") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        578,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      578,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant265" !== "variant265") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        579,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      579,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant266" !== "variant266") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        580,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      580,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant267" !== "variant267") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        581,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      581,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant268" !== "variant268") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        582,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      582,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant269" !== "variant269") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        583,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      583,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant270" !== "variant270") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        584,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      584,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant271" !== "variant271") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        585,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      585,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant272" !== "variant272") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        586,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      586,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant273" !== "variant273") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        587,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      587,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant274" !== "variant274") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        588,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      588,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant275" !== "variant275") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        589,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      589,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant276" !== "variant276") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        590,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      590,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant277" !== "variant277") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        591,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      591,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant278" !== "variant278") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        592,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      592,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant279" !== "variant279") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        593,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      593,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant280" !== "variant280") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        594,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      594,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant281" !== "variant281") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        595,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      595,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant282" !== "variant282") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        596,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      596,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant283" !== "variant283") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        597,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      597,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant284" !== "variant284") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        598,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      598,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant285" !== "variant285") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        599,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      599,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant286" !== "variant286") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        600,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      600,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant287" !== "variant287") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        601,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      601,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant288" !== "variant288") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        602,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      602,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant289" !== "variant289") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        603,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      603,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant290" !== "variant290") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        604,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      604,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant291" !== "variant291") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        605,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      605,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant292" !== "variant292") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        606,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      606,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant293" !== "variant293") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        607,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      607,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant294" !== "variant294") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        608,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      608,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant295" !== "variant295") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        609,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      609,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant296" !== "variant296") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        610,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      610,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant297" !== "variant297") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        611,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      611,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant298" !== "variant298") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        612,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      612,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if ("variant299" !== "variant299") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        613,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      613,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant0"), "variant0")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        614,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      614,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant1"), "variant1")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        615,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      615,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant2"), "variant2")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        616,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      616,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant3"), "variant3")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        617,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      617,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant4"), "variant4")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        618,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      618,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant5"), "variant5")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        619,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      619,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant6"), "variant6")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        620,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      620,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant7"), "variant7")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        621,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      621,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant8"), "variant8")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        622,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      622,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant9"), "variant9")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        623,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      623,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant10"), "variant10")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        624,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      624,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant11"), "variant11")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        625,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      625,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant12"), "variant12")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        626,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      626,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant13"), "variant13")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        627,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      627,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant14"), "variant14")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        628,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      628,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant15"), "variant15")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        629,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      629,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant16"), "variant16")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        630,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      630,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant17"), "variant17")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        631,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      631,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant18"), "variant18")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        632,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      632,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant19"), "variant19")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        633,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      633,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant20"), "variant20")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        634,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      634,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant21"), "variant21")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        635,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      635,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant22"), "variant22")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        636,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant23"), "variant23")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        637,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant24"), "variant24")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        638,
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-    }
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+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant25"), "variant25")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        639,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant26"), "variant26")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        640,
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+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
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+  };
 }
 
 if (!eq(tFromJs("variant27"), "variant27")) {
-  throw new Error("Assert_failure", {
-    cause: {
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-      _1: [
-        "big_polyvar_test.res",
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+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
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+  };
 }
 
 if (!eq(tFromJs("variant28"), "variant28")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        642,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      642,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant29"), "variant29")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        643,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      643,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant30"), "variant30")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        644,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      644,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant31"), "variant31")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        645,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      645,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant32"), "variant32")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        646,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      646,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant33"), "variant33")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        647,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      647,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant34"), "variant34")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        648,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      648,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant35"), "variant35")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        649,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      649,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant36"), "variant36")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        650,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      650,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant37"), "variant37")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        651,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      651,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant38"), "variant38")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        652,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      652,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant39"), "variant39")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        653,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      653,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant40"), "variant40")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        654,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      654,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant41"), "variant41")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        655,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      655,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant42"), "variant42")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        656,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      656,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant43"), "variant43")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        657,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      657,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant44"), "variant44")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        658,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      658,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant45"), "variant45")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        659,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      659,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant46"), "variant46")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        660,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      660,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant47"), "variant47")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        661,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      661,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant48"), "variant48")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        662,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      662,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant49"), "variant49")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        663,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      663,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant50"), "variant50")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        664,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      664,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant51"), "variant51")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        665,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      665,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant52"), "variant52")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        666,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      666,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant53"), "variant53")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        667,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      667,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant54"), "variant54")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        668,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      668,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant55"), "variant55")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        669,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      669,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant56"), "variant56")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        670,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      670,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant57"), "variant57")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        671,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      671,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant58"), "variant58")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        672,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      672,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant59"), "variant59")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        673,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      673,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant60"), "variant60")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        674,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      674,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant61"), "variant61")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        675,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      675,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant62"), "variant62")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        676,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      676,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant63"), "variant63")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        677,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      677,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant64"), "variant64")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        678,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      678,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant65"), "variant65")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        679,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      679,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant66"), "variant66")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        680,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      680,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant67"), "variant67")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        681,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      681,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant68"), "variant68")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        682,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant69"), "variant69")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        683,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant70"), "variant70")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        684,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
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-      _1: [
-        "big_polyvar_test.res",
-        685,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
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+      0
+    ],
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+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        686,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
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+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
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-      _1: [
-        "big_polyvar_test.res",
-        687,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
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+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        688,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      688,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant75"), "variant75")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        689,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      689,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant76"), "variant76")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        690,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      690,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant77"), "variant77")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        691,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      691,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant78"), "variant78")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        692,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      692,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant79"), "variant79")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        693,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      693,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant80"), "variant80")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        694,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      694,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant81"), "variant81")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        695,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      695,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant82"), "variant82")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        696,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      696,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant83"), "variant83")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        697,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      697,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant84"), "variant84")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        698,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      698,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant85"), "variant85")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        699,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      699,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant86"), "variant86")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        700,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      700,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant87"), "variant87")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        701,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      701,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant88"), "variant88")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        702,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      702,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant89"), "variant89")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        703,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      703,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant90"), "variant90")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        704,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      704,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant91"), "variant91")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        705,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      705,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant92"), "variant92")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        706,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      706,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant93"), "variant93")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        707,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      707,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant94"), "variant94")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        708,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      708,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant95"), "variant95")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        709,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      709,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant96"), "variant96")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        710,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      710,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant97"), "variant97")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        711,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      711,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant98"), "variant98")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        712,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      712,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant99"), "variant99")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        713,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      713,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant100"), "variant100")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        714,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      714,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant101"), "variant101")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        715,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      715,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant102"), "variant102")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        716,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      716,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant103"), "variant103")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        717,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      717,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant104"), "variant104")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        718,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      718,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant105"), "variant105")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        719,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      719,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant106"), "variant106")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        720,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      720,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant107"), "variant107")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        721,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      721,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant108"), "variant108")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        722,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      722,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant109"), "variant109")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        723,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      723,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant110"), "variant110")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        724,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      724,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant111"), "variant111")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        725,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      725,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant112"), "variant112")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        726,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      726,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant113"), "variant113")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        727,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      727,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant114"), "variant114")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        728,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      728,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant115"), "variant115")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        729,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      729,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant116"), "variant116")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        730,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      730,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant117"), "variant117")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        731,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      731,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant118"), "variant118")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        732,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      732,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant119"), "variant119")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        733,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      733,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant120"), "variant120")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        734,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      734,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant121"), "variant121")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        735,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      735,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant122"), "variant122")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        736,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      736,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant123"), "variant123")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        737,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      737,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant124"), "variant124")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        738,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      738,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant125"), "variant125")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        739,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      739,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant126"), "variant126")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        740,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      740,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant127"), "variant127")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        741,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      741,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant128"), "variant128")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        742,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      742,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant129"), "variant129")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        743,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      743,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant130"), "variant130")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        744,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      744,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant131"), "variant131")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        745,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      745,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant132"), "variant132")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        746,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      746,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant133"), "variant133")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        747,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      747,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant134"), "variant134")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        748,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      748,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant135"), "variant135")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        749,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      749,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant136"), "variant136")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        750,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      750,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant137"), "variant137")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        751,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      751,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant138"), "variant138")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        752,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      752,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant139"), "variant139")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        753,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      753,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant140"), "variant140")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        754,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      754,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant141"), "variant141")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        755,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      755,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant142"), "variant142")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        756,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      756,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant143"), "variant143")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        757,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      757,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant144"), "variant144")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        758,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      758,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant145"), "variant145")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        759,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      759,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant146"), "variant146")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        760,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      760,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant147"), "variant147")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        761,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      761,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant148"), "variant148")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        762,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      762,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant149"), "variant149")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        763,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      763,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant150"), "variant150")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        764,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      764,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant151"), "variant151")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        765,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      765,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant152"), "variant152")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        766,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      766,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant153"), "variant153")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        767,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      767,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant154"), "variant154")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        768,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      768,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant155"), "variant155")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        769,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      769,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant156"), "variant156")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        770,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      770,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant157"), "variant157")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        771,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      771,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant158"), "variant158")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        772,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      772,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant159"), "variant159")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        773,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      773,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant160"), "variant160")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        774,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      774,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant161"), "variant161")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        775,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      775,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant162"), "variant162")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        776,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      776,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant163"), "variant163")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        777,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      777,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant164"), "variant164")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        778,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      778,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant165"), "variant165")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        779,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      779,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant166"), "variant166")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        780,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      780,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant167"), "variant167")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        781,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      781,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant168"), "variant168")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        782,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      782,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant169"), "variant169")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        783,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      783,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant170"), "variant170")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        784,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      784,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant171"), "variant171")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        785,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      785,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant172"), "variant172")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        786,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      786,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant173"), "variant173")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        787,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      787,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant174"), "variant174")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        788,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      788,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant175"), "variant175")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        789,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      789,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant176"), "variant176")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        790,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      790,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant177"), "variant177")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        791,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      791,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant178"), "variant178")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        792,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      792,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant179"), "variant179")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        793,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      793,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant180"), "variant180")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        794,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      794,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant181"), "variant181")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        795,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      795,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant182"), "variant182")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        796,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      796,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant183"), "variant183")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        797,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      797,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant184"), "variant184")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        798,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      798,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant185"), "variant185")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        799,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      799,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant186"), "variant186")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        800,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      800,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant187"), "variant187")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        801,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      801,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant188"), "variant188")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        802,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      802,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant189"), "variant189")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        803,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      803,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant190"), "variant190")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        804,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      804,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant191"), "variant191")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        805,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      805,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant192"), "variant192")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        806,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      806,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant193"), "variant193")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        807,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      807,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant194"), "variant194")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        808,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      808,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant195"), "variant195")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        809,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      809,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant196"), "variant196")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        810,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      810,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant197"), "variant197")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        811,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      811,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant198"), "variant198")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        812,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      812,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant199"), "variant199")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        813,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      813,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant200"), "variant200")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        814,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      814,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant201"), "variant201")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        815,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      815,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant202"), "variant202")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        816,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      816,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant203"), "variant203")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        817,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      817,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant204"), "variant204")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        818,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      818,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant205"), "variant205")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        819,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      819,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant206"), "variant206")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        820,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      820,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant207"), "variant207")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        821,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      821,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant208"), "variant208")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        822,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      822,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant209"), "variant209")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        823,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      823,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant210"), "variant210")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        824,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      824,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant211"), "variant211")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        825,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      825,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant212"), "variant212")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        826,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      826,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant213"), "variant213")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        827,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      827,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant214"), "variant214")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        828,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      828,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant215"), "variant215")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        829,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      829,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant216"), "variant216")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        830,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      830,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant217"), "variant217")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        831,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      831,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant218"), "variant218")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        832,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      832,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant219"), "variant219")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        833,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      833,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant220"), "variant220")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        834,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      834,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant221"), "variant221")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        835,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      835,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant222"), "variant222")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        836,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      836,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant223"), "variant223")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        837,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      837,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant224"), "variant224")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        838,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      838,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant225"), "variant225")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        839,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      839,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant226"), "variant226")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        840,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      840,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant227"), "variant227")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        841,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      841,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant228"), "variant228")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        842,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      842,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant229"), "variant229")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        843,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      843,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant230"), "variant230")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        844,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      844,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant231"), "variant231")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        845,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      845,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant232"), "variant232")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        846,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      846,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant233"), "variant233")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        847,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      847,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant234"), "variant234")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        848,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      848,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant235"), "variant235")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        849,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      849,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant236"), "variant236")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        850,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      850,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant237"), "variant237")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        851,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      851,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant238"), "variant238")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        852,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      852,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant239"), "variant239")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        853,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      853,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant240"), "variant240")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        854,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      854,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant241"), "variant241")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        855,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      855,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant242"), "variant242")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        856,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      856,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant243"), "variant243")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        857,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      857,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant244"), "variant244")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        858,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      858,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant245"), "variant245")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        859,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      859,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant246"), "variant246")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        860,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      860,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant247"), "variant247")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        861,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      861,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant248"), "variant248")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        862,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      862,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant249"), "variant249")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        863,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant250"), "variant250")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        864,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      864,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        865,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      865,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        866,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        867,
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-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
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+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        868,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
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-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        869,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
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+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant256"), "variant256")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        870,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      870,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant257"), "variant257")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        871,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      871,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant258"), "variant258")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        872,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      872,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant259"), "variant259")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        873,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      873,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant260"), "variant260")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        874,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      874,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant261"), "variant261")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        875,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      875,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant262"), "variant262")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        876,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      876,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant263"), "variant263")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        877,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      877,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant264"), "variant264")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        878,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      878,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant265"), "variant265")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        879,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      879,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant266"), "variant266")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        880,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      880,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant267"), "variant267")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        881,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      881,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant268"), "variant268")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        882,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      882,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant269"), "variant269")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        883,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      883,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant270"), "variant270")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        884,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      884,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant271"), "variant271")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        885,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      885,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant272"), "variant272")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        886,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      886,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant273"), "variant273")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        887,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      887,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant274"), "variant274")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        888,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      888,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant275"), "variant275")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        889,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      889,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant276"), "variant276")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        890,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      890,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant277"), "variant277")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        891,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      891,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant278"), "variant278")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        892,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      892,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant279"), "variant279")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        893,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      893,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant280"), "variant280")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        894,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      894,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant281"), "variant281")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        895,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      895,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant282"), "variant282")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        896,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      896,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant283"), "variant283")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        897,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      897,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant284"), "variant284")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        898,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      898,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant285"), "variant285")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        899,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      899,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant286"), "variant286")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        900,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      900,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant287"), "variant287")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        901,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      901,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant288"), "variant288")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        902,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      902,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant289"), "variant289")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        903,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      903,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant290"), "variant290")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        904,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      904,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant291"), "variant291")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        905,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      905,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant292"), "variant292")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        906,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      906,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant293"), "variant293")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        907,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      907,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant294"), "variant294")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        908,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      908,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant295"), "variant295")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        909,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      909,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant296"), "variant296")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        910,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      910,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant297"), "variant297")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        911,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      911,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant298"), "variant298")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        912,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      912,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("variant299"), "variant299")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        913,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      913,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (!eq(tFromJs("xx"), undefined)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "big_polyvar_test.res",
-        914,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "big_polyvar_test.res",
+      914,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 exports.tToJs = tToJs;
diff --git a/jscomp/test/bs_array_test.js b/jscomp/test/bs_array_test.js
index 610ef1fa8b..e27e892f58 100644
--- a/jscomp/test/bs_array_test.js
+++ b/jscomp/test/bs_array_test.js
@@ -122,16 +122,15 @@ let v$1 = [
 ];
 
 if (!Belt_Array.set(v$1, 0, 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_array_test.res",
-        51,
-        6
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_array_test.res",
+      51,
+      6
+    ],
+    Error: new Error()
+  };
 }
 
 b("File \"bs_array_test.res\", line 48, characters 4-11", Belt_Array.getExn(v$1, 0) === 0);
@@ -142,16 +141,15 @@ let v$2 = [
 ];
 
 if (!Belt_Array.set(v$2, 1, 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_array_test.res",
-        59,
-        6
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_array_test.res",
+      59,
+      6
+    ],
+    Error: new Error()
+  };
 }
 
 b("File \"bs_array_test.res\", line 56, characters 4-11", Belt_Array.getExn(v$2, 1) === 0);
@@ -254,16 +252,15 @@ function addone(x) {
 
 function makeMatrixExn(sx, sy, init) {
   if (!(sx >= 0 && sy >= 0)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_array_test.res",
-          116,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_array_test.res",
+        116,
+        2
+      ],
+      Error: new Error()
+    };
   }
   let res = new Array(sx);
   for (let x = 0; x < sx; ++x) {
diff --git a/jscomp/test/bs_queue_test.js b/jscomp/test/bs_queue_test.js
index 23b344361b..203429cc14 100644
--- a/jscomp/test/bs_queue_test.js
+++ b/jscomp/test/bs_queue_test.js
@@ -43,45 +43,42 @@ let q = {
 };
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), []) && q.length === 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        25,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      25,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 1), q)), [1]) && q.length === 1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        26,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      26,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 2), q)), [
     1,
     2
   ]) && q.length === 2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        27,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      27,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 3), q)), [
@@ -89,16 +86,15 @@ if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 3), q))
     2,
     3
   ]) && q.length === 3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        28,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      28,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 4), q)), [
@@ -107,29 +103,27 @@ if (!(Caml_obj.equal(Belt_MutableQueue.toArray((Belt_MutableQueue.add(q, 4), q))
     3,
     4
   ]) && q.length === 4)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        29,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      29,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        30,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      30,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), [
@@ -137,110 +131,102 @@ if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), [
     3,
     4
   ]) && q.length === 3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        31,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      31,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        32,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      32,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), [
     3,
     4
   ]) && q.length === 2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        33,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      33,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        34,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      34,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), [4]) && q.length === 1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        35,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      35,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q) !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        36,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      36,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(Belt_MutableQueue.toArray(q), []) && q.length === 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        37,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      37,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.popExn, q)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        38,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      38,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$1 = {
@@ -250,68 +236,63 @@ let q$1 = {
 };
 
 if (Belt_MutableQueue.popExn((Belt_MutableQueue.add(q$1, 1), q$1)) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        43,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      43,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.popExn, q$1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        44,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      44,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn((Belt_MutableQueue.add(q$1, 2), q$1)) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        45,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      45,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.popExn, q$1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        46,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      46,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        47,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      47,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$2 = {
@@ -321,146 +302,135 @@ let q$2 = {
 };
 
 if (Belt_MutableQueue.peekExn((Belt_MutableQueue.add(q$2, 1), q$2)) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        52,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      52,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.peekExn((Belt_MutableQueue.add(q$2, 2), q$2)) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        53,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      53,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.peekExn((Belt_MutableQueue.add(q$2, 3), q$2)) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        54,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      54,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.peekExn(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        55,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      55,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        56,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      56,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.peekExn(q$2) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        57,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      57,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q$2) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        58,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      58,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.peekExn(q$2) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        59,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      59,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.popExn(q$2) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        60,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      60,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.peekExn, q$2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        61,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      61,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.peekExn, q$2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        62,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      62,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$3 = {
@@ -476,29 +446,27 @@ for (let i = 1; i <= 10; ++i) {
 Belt_MutableQueue.clear(q$3);
 
 if (q$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        71,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      71,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Belt_MutableQueue.popExn, q$3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        72,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      72,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(q$3, {
@@ -506,31 +474,29 @@ if (!Caml_obj.equal(q$3, {
     first: undefined,
     last: undefined
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        73,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      73,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Belt_MutableQueue.add(q$3, 42);
 
 if (Belt_MutableQueue.popExn(q$3) !== 42) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        75,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      75,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1 = {
@@ -557,16 +523,15 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1), [
     9,
     10
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        84,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      84,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2), [
@@ -581,72 +546,67 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2), [
     9,
     10
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        85,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      85,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q1.length !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        86,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      86,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2.length !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        87,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      87,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 for (let i$2 = 1; i$2 <= 10; ++i$2) {
   if (Belt_MutableQueue.popExn(q1) !== i$2) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          89,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        89,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
 
 for (let i$3 = 1; i$3 <= 10; ++i$3) {
   if (Belt_MutableQueue.popExn(q2) !== i$3) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          92,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        92,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
@@ -658,99 +618,92 @@ let q$4 = {
 };
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        98,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      98,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 for (let i$4 = 1; i$4 <= 10; ++i$4) {
   Belt_MutableQueue.add(q$4, i$4);
   if (q$4.length !== i$4) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          101,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        101,
+        4
+      ],
+      Error: new Error()
+    };
   }
   if (q$4.length === 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          102,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        102,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
 
 for (let i$5 = 10; i$5 >= 1; --i$5) {
   if (q$4.length !== i$5) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          105,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        105,
+        4
+      ],
+      Error: new Error()
+    };
   }
   if (q$4.length === 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          106,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        106,
+        4
+      ],
+      Error: new Error()
+    };
   }
   Belt_MutableQueue.popExn(q$4);
 }
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        109,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      109,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        110,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      110,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$5 = {
@@ -769,16 +722,15 @@ let i$7 = {
 
 Belt_MutableQueue.forEach(q$5, j => {
   if (i$7.contents !== j) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "bs_queue_test.res",
-          120,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "bs_queue_test.res",
+        120,
+        4
+      ],
+      Error: new Error()
+    };
   }
   i$7.contents = i$7.contents + 1 | 0;
 });
@@ -796,109 +748,101 @@ let q2$1 = {
 };
 
 if (q1$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        127,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      127,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$1), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        128,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      128,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        129,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      129,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$1), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        130,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      130,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Belt_MutableQueue.transfer(q1$1, q2$1);
 
 if (q1$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        132,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      132,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$1), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        133,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      133,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        134,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      134,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$1), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        135,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      135,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$2 = {
@@ -918,16 +862,15 @@ for (let i$8 = 1; i$8 <= 4; ++i$8) {
 }
 
 if (q1$2.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        143,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      143,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$2), [
@@ -936,83 +879,77 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$2), [
     3,
     4
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        144,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      144,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$2.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        145,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      145,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$2), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        146,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      146,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Belt_MutableQueue.transfer(q1$2, q2$2);
 
 if (q1$2.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        148,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      148,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$2), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        149,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      149,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$2.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        150,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      150,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$2), [
@@ -1021,16 +958,15 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$2), [
     3,
     4
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        151,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      151,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$3 = {
@@ -1050,42 +986,39 @@ for (let i$9 = 5; i$9 <= 8; ++i$9) {
 }
 
 if (q1$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        159,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      159,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$3), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        160,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      160,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$3.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        161,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      161,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$3), [
@@ -1094,57 +1027,53 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$3), [
     7,
     8
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        162,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      162,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Belt_MutableQueue.transfer(q1$3, q2$3);
 
 if (q1$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        164,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      164,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$3), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        165,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      165,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$3.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        166,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      166,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$3), [
@@ -1153,16 +1082,15 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$3), [
     7,
     8
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        167,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      167,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$4 = {
@@ -1186,16 +1114,15 @@ for (let i$11 = 5; i$11 <= 8; ++i$11) {
 }
 
 if (q1$4.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        178,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      178,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$4), [
@@ -1204,29 +1131,27 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$4), [
     3,
     4
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        179,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      179,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$4.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        180,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      180,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$4), [
@@ -1235,44 +1160,41 @@ if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$4), [
     7,
     8
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        181,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      181,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Belt_MutableQueue.transfer(q1$4, q2$4);
 
 if (q1$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        183,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      183,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q1$4), [])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        184,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      184,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let v = [
@@ -1287,42 +1209,39 @@ let v = [
 ];
 
 if (q2$4.length !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        186,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      186,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Belt_MutableQueue.toArray(q2$4), v)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        187,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      187,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Belt_MutableQueue.reduce(q2$4, 0, (x, y) => x - y | 0) !== Belt_Array.reduce(v, 0, (x, y) => x - y | 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "bs_queue_test.res",
-        189,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "bs_queue_test.res",
+      189,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 console.log("OK");
diff --git a/jscomp/test/chn_test.js b/jscomp/test/chn_test.js
index 17e05c04c4..cbd83e9c6e 100644
--- a/jscomp/test/chn_test.js
+++ b/jscomp/test/chn_test.js
@@ -38,16 +38,15 @@ function convert(s) {
     if (x$1 !== undefined) {
       return x$1;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "chn_test.res",
-          18,
-          16
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "chn_test.res",
+        18,
+        16
+      ],
+      Error: new Error()
+    };
   }));
 }
 
diff --git a/jscomp/test/const_defs_test.js b/jscomp/test/const_defs_test.js
index 2e2bb57544..a1b5eba93b 100644
--- a/jscomp/test/const_defs_test.js
+++ b/jscomp/test/const_defs_test.js
@@ -5,12 +5,11 @@
 let u = 3;
 
 function f() {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "hi"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "hi",
+    Error: new Error()
+  };
 }
 
 exports.u = u;
diff --git a/jscomp/test/custom_error_test.js b/jscomp/test/custom_error_test.js
index 0e19bcac08..882aa937a0 100644
--- a/jscomp/test/custom_error_test.js
+++ b/jscomp/test/custom_error_test.js
@@ -14,9 +14,7 @@ function test_js_error() {
       console.log(err._1.stack);
       return;
     }
-    throw new Error(err.RE_EXN_ID, {
-      cause: err
-    });
+    throw err;
   }
   return e;
 }
@@ -28,13 +26,9 @@ function test_js_error2() {
     let e = Caml_js_exceptions.internalToOCamlException(raw_e);
     if (e.RE_EXN_ID === Js_exn.$$Error) {
       console.log(e._1.stack);
-      throw new Error(e.RE_EXN_ID, {
-        cause: e
-      });
+      throw e;
     }
-    throw new Error(e.RE_EXN_ID, {
-      cause: e
-    });
+    throw e;
   }
 }
 
@@ -48,9 +42,7 @@ function example1() {
       console.log(err._1.stack);
       return;
     }
-    throw new Error(err.RE_EXN_ID, {
-      cause: err
-    });
+    throw err;
   }
   return v;
 }
@@ -63,9 +55,7 @@ function example2() {
     if (exn.RE_EXN_ID === Js_exn.$$Error) {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/defunctor_make_test.js b/jscomp/test/defunctor_make_test.js
index 1e0ac446ce..efc2f442f8 100644
--- a/jscomp/test/defunctor_make_test.js
+++ b/jscomp/test/defunctor_make_test.js
@@ -44,12 +44,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r._4;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l._3;
     let ld = l._2;
@@ -61,12 +60,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr._0), lr._1, lr._2, create(lr._3, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -79,12 +77,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r._3;
   let rd = r._2;
@@ -96,12 +93,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl._0), rl._1, rl._2, create(rl._3, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, compare, x_) {
diff --git a/jscomp/test/demo_int_map.js b/jscomp/test/demo_int_map.js
index 50052476dc..71b93d86cc 100644
--- a/jscomp/test/demo_int_map.js
+++ b/jscomp/test/demo_int_map.js
@@ -30,12 +30,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -47,12 +46,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -65,12 +63,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -82,12 +79,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, param) {
@@ -140,11 +136,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = x - param.v | 0;
     if (c === 0) {
diff --git a/jscomp/test/earger_curry_test.js b/jscomp/test/earger_curry_test.js
index c5cc837bc7..fb598eacf0 100644
--- a/jscomp/test/earger_curry_test.js
+++ b/jscomp/test/earger_curry_test.js
@@ -24,12 +24,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f$1(0));
   for (let i = 1; i < l; ++i) {
diff --git a/jscomp/test/equal_exception_test.js b/jscomp/test/equal_exception_test.js
index 263778a862..04bff576e3 100644
--- a/jscomp/test/equal_exception_test.js
+++ b/jscomp/test/equal_exception_test.js
@@ -13,73 +13,66 @@ let v = "gso";
 
 function is_equal() {
   if (Caml_bytes.get(Bytes.make(3, /* 'a' */97), 0) !== /* 'a' */97) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "equal_exception_test.res",
-          4,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "equal_exception_test.res",
+        4,
+        2
+      ],
+      Error: new Error()
+    };
   }
   if (Bytes.make(3, /* 'a' */97)[0] !== /* 'a' */97) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "equal_exception_test.res",
-          5,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "equal_exception_test.res",
+        5,
+        2
+      ],
+      Error: new Error()
+    };
   }
   let u = Bytes.make(3, /* 'a' */97);
   u[0] = /* 'b' */98;
   if (u[0] !== /* 'b' */98) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "equal_exception_test.res",
-          8,
-          2
-        ]
-      }
-    });
-  }
-  if (Caml_string.get(v, 0) === /* 'g' */103) {
-    return;
-  }
-  throw new Error("Assert_failure", {
-    cause: {
+    throw {
       RE_EXN_ID: "Assert_failure",
       _1: [
         "equal_exception_test.res",
-        9,
+        8,
         2
-      ]
-    }
-  });
+      ],
+      Error: new Error()
+    };
+  }
+  if (Caml_string.get(v, 0) === /* 'g' */103) {
+    return;
+  }
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "equal_exception_test.res",
+      9,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function is_exception() {
   try {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   } catch (raw_exn) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Not_found") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -90,33 +83,26 @@ function is_normal_exception(_x) {
     _1: 3
   };
   try {
-    throw new Error(v.RE_EXN_ID, {
-      cause: v
-    });
+    throw v;
   } catch (raw_exn) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === A) {
       if (exn._1 === 3) {
         return;
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
 function is_arbitrary_exception() {
   let A = /* @__PURE__ */Caml_exceptions.create("A");
   try {
-    throw new Error(A, {
-      cause: {
-        RE_EXN_ID: A
-      }
-    });
+    throw {
+      RE_EXN_ID: A,
+      Error: new Error()
+    };
   } catch (exn) {
     return;
   }
@@ -165,29 +151,27 @@ let Not_found = /* @__PURE__ */Caml_exceptions.create("Equal_exception_test.Not_
 if (Caml_obj.equal(e, {
     RE_EXN_ID: Not_found
   }) !== false) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "equal_exception_test.res",
-        50,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "equal_exception_test.res",
+      50,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (Not_found === "Not_found" !== false) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "equal_exception_test.res",
-        51,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "equal_exception_test.res",
+      51,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 Mt.from_suites("exception", suites);
diff --git a/jscomp/test/exception_raise_test.js b/jscomp/test/exception_raise_test.js
index e847b09f39..d39772e1ca 100644
--- a/jscomp/test/exception_raise_test.js
+++ b/jscomp/test/exception_raise_test.js
@@ -94,16 +94,15 @@ try {
   if (x$3.RE_EXN_ID === A || x$3.RE_EXN_ID === Js_exn.$$Error) {
     a0 = x$3._1;
   } else {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "exception_raise_test.res",
-          104,
-          7
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "exception_raise_test.res",
+        104,
+        7
+      ],
+      Error: new Error()
+    };
   }
 }
 
@@ -154,16 +153,15 @@ let suites = {
               _1: 2
             };
           }
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "exception_raise_test.res",
-                127,
-                15
-              ]
-            }
-          });
+          throw {
+            RE_EXN_ID: "Assert_failure",
+            _1: [
+              "exception_raise_test.res",
+              127,
+              15
+            ],
+            Error: new Error()
+          };
         }
       ],
       tl: /* [] */0
@@ -187,11 +185,10 @@ try {
 }
 
 try {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 } catch (raw_e$3) {
   let e$1 = Caml_js_exceptions.internalToOCamlException(raw_e$3);
   eq("File \"exception_raise_test.res\", line 141, characters 10-17", Caml_js_exceptions.as_js_exn(e$1) !== undefined, false);
diff --git a/jscomp/test/exception_rebound_err_test.js b/jscomp/test/exception_rebound_err_test.js
index e795fde624..4fe7c956c2 100644
--- a/jscomp/test/exception_rebound_err_test.js
+++ b/jscomp/test/exception_rebound_err_test.js
@@ -70,9 +70,7 @@ function f(g) {
     if (exn.RE_EXN_ID === "Not_found") {
       return 1;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/exception_value_test.js b/jscomp/test/exception_value_test.js
index dee7400ffb..8be5392bda 100644
--- a/jscomp/test/exception_value_test.js
+++ b/jscomp/test/exception_value_test.js
@@ -6,35 +6,32 @@ let Caml_exceptions = require("../../lib/js/caml_exceptions.js");
 let Caml_js_exceptions = require("../../lib/js/caml_js_exceptions.js");
 
 function f() {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function assert_f(x) {
   if (x <= 3) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "exception_value_test.res",
-          4,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "exception_value_test.res",
+        4,
+        11
+      ],
+      Error: new Error()
+    };
   }
   return 3;
 }
 
 function hh() {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let A = /* @__PURE__ */Caml_exceptions.create("Exception_value_test.A");
@@ -56,9 +53,7 @@ function test_not_found(f, param) {
     if (exn.RE_EXN_ID === "Not_found") {
       return 2;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -69,13 +64,9 @@ function test_js_error2() {
     let e = Caml_js_exceptions.internalToOCamlException(raw_e);
     if (e.RE_EXN_ID === Js_exn.$$Error) {
       console.log(e._1.stack);
-      throw new Error(e.RE_EXN_ID, {
-        cause: e
-      });
+      throw e;
     }
-    throw new Error(e.RE_EXN_ID, {
-      cause: e
-    });
+    throw e;
   }
 }
 
diff --git a/jscomp/test/ext_array_test.js b/jscomp/test/ext_array_test.js
index 7c824a62e7..db46f8d66a 100644
--- a/jscomp/test/ext_array_test.js
+++ b/jscomp/test/ext_array_test.js
@@ -105,12 +105,11 @@ function filter_map(f, a) {
 
 function range(from, to_) {
   if (from > to_) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_array_test.range"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_array_test.range",
+      Error: new Error()
+    };
   }
   return $$Array.init((to_ - from | 0) + 1 | 0, i => i + from | 0);
 }
@@ -118,12 +117,11 @@ function range(from, to_) {
 function map2i(f, a, b) {
   let len = a.length;
   if (len !== b.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_array_test.map2i"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_array_test.map2i",
+      Error: new Error()
+    };
   }
   return $$Array.mapi((i, a) => f(i, a, b[i]), a);
 }
diff --git a/jscomp/test/ext_bytes_test.js b/jscomp/test/ext_bytes_test.js
index 3a7ad98c91..768eb67bc4 100644
--- a/jscomp/test/ext_bytes_test.js
+++ b/jscomp/test/ext_bytes_test.js
@@ -134,11 +134,10 @@ function starts_with(xs, prefix, p) {
   try {
     for (let i = 0; i < len2; ++i) {
       if (!p(Caml_bytes.get(xs, i), Caml_bytes.get(prefix, i))) {
-        throw new Error(H, {
-          cause: {
-            RE_EXN_ID: H
-          }
-        });
+        throw {
+          RE_EXN_ID: H,
+          Error: new Error()
+        };
       }
       
     }
@@ -148,9 +147,7 @@ function starts_with(xs, prefix, p) {
     if (exn.RE_EXN_ID === H) {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/ext_filename_test.js b/jscomp/test/ext_filename_test.js
index 7628c95abe..40c76532e1 100644
--- a/jscomp/test/ext_filename_test.js
+++ b/jscomp/test/ext_filename_test.js
@@ -61,16 +61,13 @@ function chop_extension(locOpt, name) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === "Invalid_argument") {
       let s = "Filename.chop_extension ( " + loc + " : " + name + " )";
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: s
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: s,
+        Error: new Error()
+      };
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -82,9 +79,7 @@ function chop_extension_if_any(fname) {
     if (exn.RE_EXN_ID === "Invalid_argument") {
       return fname;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -142,12 +137,11 @@ function node_relative_path(node_modules_shorten, file1, dep_file) {
       let i = _i;
       if (i >= len) {
         let s = "invalid path: " + file2;
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: s
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: s,
+          Error: new Error()
+        };
       }
       let curr_char = file2.codePointAt(i);
       if (!(curr_char === os_path_separator_char || curr_char === /* '.' */46)) {
@@ -172,12 +166,11 @@ function find_root_filename(_cwd, filename) {
       continue;
     }
     let s = filename + " not found from " + cwd;
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: s
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: s,
+      Error: new Error()
+    };
   };
 }
 
@@ -344,12 +337,11 @@ if (Sys.unix) {
   simple_convert_node_path_to_os_path = Ext_string_test.replace_slash_backward;
 } else {
   let s = "Unknown OS : " + Sys.os_type;
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 let $slash$slash = Filename.concat;
diff --git a/jscomp/test/ext_list_test.js b/jscomp/test/ext_list_test.js
index 5c17bb62a0..0293bd0bb7 100644
--- a/jscomp/test/ext_list_test.js
+++ b/jscomp/test/ext_list_test.js
@@ -203,22 +203,20 @@ function filter_map2(f, _xs, _ys) {
         _xs = us;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.filter_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.filter_map2",
+        Error: new Error()
+      };
     }
     if (!ys) {
       return /* [] */0;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_list_test.filter_map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_list_test.filter_map2",
+      Error: new Error()
+    };
   };
 }
 
@@ -244,22 +242,20 @@ function filter_map2i(f, xs, ys) {
           _i = i + 1 | 0;
           continue;
         }
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Ext_list_test.filter_map2i"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Ext_list_test.filter_map2i",
+          Error: new Error()
+        };
       }
       if (!ys) {
         return /* [] */0;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.filter_map2i"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.filter_map2i",
+        Error: new Error()
+      };
     };
   };
   return aux(0, xs, ys);
@@ -296,20 +292,18 @@ function flat_map2(f, lx, ly) {
         _acc = List.rev_append(f(lx$1.hd, ly$1.hd), acc);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.flat_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.flat_map2",
+        Error: new Error()
+      };
     }
     if (ly$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.flat_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.flat_map2",
+        Error: new Error()
+      };
     }
     return List.rev(acc);
   };
@@ -350,12 +344,11 @@ function map2_last(f, l1, l2) {
         }
         
       } else {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "List.map2_last"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "List.map2_last",
+          Error: new Error()
+        };
       }
     }
     if (l2) {
@@ -365,22 +358,20 @@ function map2_last(f, l1, l2) {
         tl: map2_last(f, l1$1, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2_last"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2_last",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2_last"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2_last",
+    Error: new Error()
+  };
 }
 
 function map_last(f, l1) {
@@ -413,31 +404,28 @@ function fold_right2_last(f, l1, l2, accu) {
         }
         
       } else {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "List.fold_right2"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "List.fold_right2",
+          Error: new Error()
+        };
       }
     }
     if (l2) {
       return f(false, last1, l2.hd, fold_right2_last(f, l1$1, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -450,12 +438,11 @@ function take(n, l) {
   let arr = $$Array.of_list(l);
   let arr_length = arr.length;
   if (arr_length < n) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_list_test.take"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_list_test.take",
+      Error: new Error()
+    };
   }
   return [
     $$Array.to_list($$Array.sub(arr, 0, n)),
@@ -539,12 +526,11 @@ function exclude_tail(x) {
       };
       continue;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_list_test.exclude_tail"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_list_test.exclude_tail",
+      Error: new Error()
+    };
   };
 }
 
@@ -593,23 +579,21 @@ function drop(_n, _h) {
     let h = _h;
     let n = _n;
     if (n < 0) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.drop"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.drop",
+        Error: new Error()
+      };
     }
     if (n === 0) {
       return h;
     }
     if (h === /* [] */0) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Ext_list_test.drop"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Ext_list_test.drop",
+        Error: new Error()
+      };
     }
     _h = List.tl(h);
     _n = n - 1 | 0;
@@ -774,24 +758,22 @@ function reduce_from_right(fn, lst) {
   if (match) {
     return List.fold_left((x, y) => fn(y, x), match.hd, match.tl);
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Ext_list_test.reduce"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Ext_list_test.reduce",
+    Error: new Error()
+  };
 }
 
 function reduce_from_left(fn, lst) {
   if (lst) {
     return List.fold_left(fn, lst.hd, lst.tl);
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Ext_list_test.reduce_from_left"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Ext_list_test.reduce_from_left",
+    Error: new Error()
+  };
 }
 
 function create_ref_empty() {
@@ -805,12 +787,11 @@ function ref_top(x) {
   if (match) {
     return match.hd;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Ext_list_test.ref_top"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Ext_list_test.ref_top",
+    Error: new Error()
+  };
 }
 
 function ref_empty(x) {
@@ -835,12 +816,11 @@ function ref_pop(refs) {
     refs.contents = match.tl;
     return match.hd;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Ext_list_test.ref_pop"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Ext_list_test.ref_pop",
+    Error: new Error()
+  };
 }
 
 function rev_except_last(xs) {
@@ -865,12 +845,11 @@ function rev_except_last(xs) {
       };
       continue;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_list_test.rev_except_last"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_list_test.rev_except_last",
+      Error: new Error()
+    };
   };
 }
 
@@ -891,12 +870,11 @@ function last(_xs) {
       _xs = tl;
       continue;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_list_test.last"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_list_test.last",
+      Error: new Error()
+    };
   };
 }
 
@@ -914,16 +892,15 @@ function assoc_by_string(def, k, _lst) {
     if (def !== undefined) {
       return Caml_option.valFromOption(def);
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "ext_list_test.res",
-          472,
-          14
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "ext_list_test.res",
+        472,
+        14
+      ],
+      Error: new Error()
+    };
   };
 }
 
@@ -941,16 +918,15 @@ function assoc_by_int(def, k, _lst) {
     if (def !== undefined) {
       return Caml_option.valFromOption(def);
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "ext_list_test.res",
-          487,
-          14
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "ext_list_test.res",
+        487,
+        14
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/jscomp/test/ext_pervasives_test.js b/jscomp/test/ext_pervasives_test.js
index 5527fdf735..d32b817ff6 100644
--- a/jscomp/test/ext_pervasives_test.js
+++ b/jscomp/test/ext_pervasives_test.js
@@ -11,9 +11,7 @@ function $$finally(v, action, f) {
     e = f(v);
   } catch (e$1) {
     action(v);
-    throw new Error(e$1.RE_EXN_ID, {
-      cause: e$1
-    });
+    throw e$1;
   }
   action(v);
   return e;
@@ -38,20 +36,17 @@ function is_pos_pow(n) {
         _c = c + 1 | 0;
         continue;
       }
-      throw new Error(E, {
-        cause: {
-          RE_EXN_ID: E
-        }
-      });
+      throw {
+        RE_EXN_ID: E,
+        Error: new Error()
+      };
     };
   } catch (raw_exn) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === E) {
       return -1;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -74,20 +69,17 @@ function is_pos_pow_2(n) {
         _c = c + 1 | 0;
         continue;
       }
-      throw new Error(E, {
-        cause: {
-          RE_EXN_ID: E
-        }
-      });
+      throw {
+        RE_EXN_ID: E,
+        Error: new Error()
+      };
     };
   } catch (raw_exn) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID === E) {
       return -1;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/ext_string_test.js b/jscomp/test/ext_string_test.js
index 69409ccddf..75b2da3878 100644
--- a/jscomp/test/ext_string_test.js
+++ b/jscomp/test/ext_string_test.js
@@ -213,12 +213,11 @@ function unsafe_for_all_range(s, _start, finish, p) {
 function for_all_range(s, start, finish, p) {
   let len = s.length;
   if (start < 0 || finish >= len) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_string_test.for_all_range"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_string_test.for_all_range",
+      Error: new Error()
+    };
   }
   return unsafe_for_all_range(s, start, finish, p);
 }
@@ -269,11 +268,10 @@ function find(startOpt, sub, s) {
   try {
     while ((i + n | 0) <= s_len) {
       if (unsafe_is_sub(sub, 0, s, i, n)) {
-        throw new Error(Local_exit, {
-          cause: {
-            RE_EXN_ID: Local_exit
-          }
-        });
+        throw {
+          RE_EXN_ID: Local_exit,
+          Error: new Error()
+        };
       }
       i = i + 1 | 0;
     };
@@ -283,9 +281,7 @@ function find(startOpt, sub, s) {
     if (exn.RE_EXN_ID === Local_exit) {
       return i;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -296,12 +292,11 @@ function contain_substring(s, sub) {
 function non_overlap_count(sub, s) {
   let sub_len = sub.length;
   if (sub.length === 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_string_test.non_overlap_count"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_string_test.non_overlap_count",
+      Error: new Error()
+    };
   }
   let _acc = 0;
   let _off = 0;
@@ -324,11 +319,10 @@ function rfind(sub, s) {
   try {
     while (i >= 0) {
       if (unsafe_is_sub(sub, 0, s, i, n)) {
-        throw new Error(Local_exit, {
-          cause: {
-            RE_EXN_ID: Local_exit
-          }
-        });
+        throw {
+          RE_EXN_ID: Local_exit,
+          Error: new Error()
+        };
       }
       i = i - 1 | 0;
     };
@@ -338,9 +332,7 @@ function rfind(sub, s) {
     if (exn.RE_EXN_ID === Local_exit) {
       return i;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -350,12 +342,11 @@ function tail_from(s, x) {
     return $$String.sub(s, x, len - x | 0);
   }
   let s$1 = "Ext_string_test.tail_from " + (s + (" : " + String(x)));
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s$1
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s$1,
+    Error: new Error()
+  };
 }
 
 function digits_of_str(s, offset, x) {
@@ -548,12 +539,11 @@ function unsafe_no_char_idx(x, ch, _i, last_idx) {
 function no_char(x, ch, i, len) {
   let str_len = x.length;
   if (i < 0 || i >= str_len || len >= str_len) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Ext_string_test.no_char"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Ext_string_test.no_char",
+      Error: new Error()
+    };
   }
   return unsafe_no_char(x, ch, i, len);
 }
diff --git a/jscomp/test/extensible_variant_test.js b/jscomp/test/extensible_variant_test.js
index cfadcd2dde..c80e4eac79 100644
--- a/jscomp/test/extensible_variant_test.js
+++ b/jscomp/test/extensible_variant_test.js
@@ -24,16 +24,15 @@ function to_int(x) {
   if (x.RE_EXN_ID === Int$1) {
     return x._2;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "extensible_variant_test.res",
-        16,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "extensible_variant_test.res",
+      16,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 let suites_0 = [
diff --git a/jscomp/test/flexible_array_test.js b/jscomp/test/flexible_array_test.js
index 7e932c4ae9..0a99587305 100644
--- a/jscomp/test/flexible_array_test.js
+++ b/jscomp/test/flexible_array_test.js
@@ -10,11 +10,10 @@ function sub(_tr, _k) {
     let k = _k;
     let tr = _tr;
     if (typeof tr !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (k === 1) {
       return tr._0;
@@ -40,11 +39,10 @@ function update(tr, k, w) {
         _2: "Lf"
       };
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let r = tr._2;
   let l = tr._1;
@@ -76,11 +74,10 @@ function update(tr, k, w) {
 
 function $$delete(tr, n) {
   if (typeof tr !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   if (n === 1) {
     return "Lf";
@@ -125,11 +122,10 @@ function loext(tr, w) {
 
 function lorem(tr) {
   if (typeof tr !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let l = tr._1;
   if (typeof l === "object") {
@@ -144,16 +140,15 @@ function lorem(tr) {
   if (typeof tmp !== "object") {
     return "Lf";
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "flexible_array_test.res",
-        80,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "flexible_array_test.res",
+      80,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 let empty = [
@@ -169,12 +164,11 @@ function get(param, i) {
   if (i >= 0 && i < param[1]) {
     return sub(param[0], i + 1 | 0);
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.get"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Array.get",
+    Error: new Error()
+  };
 }
 
 function set(param, i, v) {
@@ -185,12 +179,11 @@ function set(param, i, v) {
       k
     ];
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.set"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Array.set",
+    Error: new Error()
+  };
 }
 
 function push_front(param, v) {
@@ -208,12 +201,11 @@ function pop_front(param) {
       k - 1 | 0
     ];
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.pop_front"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Array.pop_front",
+    Error: new Error()
+  };
 }
 
 function push_back(param, v) {
@@ -232,12 +224,11 @@ function pop_back(param) {
       k - 1 | 0
     ];
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Array.pop_back"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Array.pop_back",
+    Error: new Error()
+  };
 }
 
 function filter_from(i, p, s) {
@@ -319,16 +310,15 @@ if (!$eq$tilde(sort(u), [
     5,
     6
   ])) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "flexible_array_test.res",
-        184,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "flexible_array_test.res",
+      184,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let v = $$Array.init(500, i => 500 - i | 0);
diff --git a/jscomp/test/format_regression.js b/jscomp/test/format_regression.js
index c89043c8cd..4f2a36aadf 100644
--- a/jscomp/test/format_regression.js
+++ b/jscomp/test/format_regression.js
@@ -3,55 +3,51 @@
 
 
 function peek_queue(param) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "format_regression.res",
-        10,
-        22
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "format_regression.res",
+      10,
+      22
+    ],
+    Error: new Error()
+  };
 }
 
 function int_of_size(param) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "format_regression.res",
-        11,
-        23
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "format_regression.res",
+      11,
+      23
+    ],
+    Error: new Error()
+  };
 }
 
 function take_queue(param) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "format_regression.res",
-        12,
-        22
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "format_regression.res",
+      12,
+      22
+    ],
+    Error: new Error()
+  };
 }
 
 function format_pp_token(param, param$1, param$2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "format_regression.res",
-        13,
-        35
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "format_regression.res",
+      13,
+      35
+    ],
+    Error: new Error()
+  };
 }
 
 function advance_loop(state) {
diff --git a/jscomp/test/fun_pattern_match.js b/jscomp/test/fun_pattern_match.js
index e2cab8232f..9b3880f260 100644
--- a/jscomp/test/fun_pattern_match.js
+++ b/jscomp/test/fun_pattern_match.js
@@ -22,16 +22,15 @@ function f3(param, param$1) {
     }
     rhs === "Uninitialized";
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "fun_pattern_match.res",
-        33,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "fun_pattern_match.res",
+      33,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function f4(param, param$1) {
@@ -45,16 +44,15 @@ function f4(param, param$1) {
     }
     rhs === "Uninitialized";
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "fun_pattern_match.res",
-        39,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "fun_pattern_match.res",
+      39,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 let x = {
diff --git a/jscomp/test/genlex_test.js b/jscomp/test/genlex_test.js
index 7aa4e74b15..00a8e97383 100644
--- a/jscomp/test/genlex_test.js
+++ b/jscomp/test/genlex_test.js
@@ -45,9 +45,7 @@ function to_list(s) {
       if (exn.RE_EXN_ID === Stream.Failure) {
         return List.rev(acc);
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     _acc = {
       hd: v,
diff --git a/jscomp/test/gpr_1150.js b/jscomp/test/gpr_1150.js
index d8286103da..b5cc9c15ab 100644
--- a/jscomp/test/gpr_1150.js
+++ b/jscomp/test/gpr_1150.js
@@ -215,16 +215,15 @@ function f(children) {
     ];
   }
   if (children$15.tl) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "gpr_1150.res",
-          100,
-          62
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "gpr_1150.res",
+        100,
+        62
+      ],
+      Error: new Error()
+    };
   }
   return [
     a0,
diff --git a/jscomp/test/gpr_1245_test.js b/jscomp/test/gpr_1245_test.js
index e1e0e9044b..3ed9c70903 100644
--- a/jscomp/test/gpr_1245_test.js
+++ b/jscomp/test/gpr_1245_test.js
@@ -46,9 +46,7 @@ function a1(f) {
     if (exn.RE_EXN_ID === E) {
       return 1;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/gpr_1698_test.js b/jscomp/test/gpr_1698_test.js
index 70186a2079..a85cfeee77 100644
--- a/jscomp/test/gpr_1698_test.js
+++ b/jscomp/test/gpr_1698_test.js
@@ -48,16 +48,15 @@ function compare(context, state, _a, _b) {
             exit$2 = 4;
             break;
           case "Frac" :
-            throw new Error("Assert_failure", {
-              cause: {
-                RE_EXN_ID: "Assert_failure",
-                _1: [
-                  "gpr_1698_test.res",
-                  41,
-                  9
-                ]
-              }
-            });
+            throw {
+              RE_EXN_ID: "Assert_failure",
+              _1: [
+                "gpr_1698_test.res",
+                41,
+                9
+              ],
+              Error: new Error()
+            };
           case "Pow" :
           case "Gcd" :
             exit = 1;
@@ -74,16 +73,15 @@ function compare(context, state, _a, _b) {
       case "Frac" :
         switch (b.TAG) {
           case "Val" :
-            throw new Error("Assert_failure", {
-              cause: {
-                RE_EXN_ID: "Assert_failure",
-                _1: [
-                  "gpr_1698_test.res",
-                  41,
-                  9
-                ]
-              }
-            });
+            throw {
+              RE_EXN_ID: "Assert_failure",
+              _1: [
+                "gpr_1698_test.res",
+                41,
+                9
+              ],
+              Error: new Error()
+            };
           case "Neg" :
             exit$3 = 5;
             break;
diff --git a/jscomp/test/gpr_1701_test.js b/jscomp/test/gpr_1701_test.js
index dbf9f7c67a..b55d0aa9b7 100644
--- a/jscomp/test/gpr_1701_test.js
+++ b/jscomp/test/gpr_1701_test.js
@@ -9,11 +9,10 @@ let Foo = /* @__PURE__ */Caml_exceptions.create("Gpr_1701_test.Foo");
 
 function test(n) {
   if (n === 0) {
-    throw new Error(Foo, {
-      cause: {
-        RE_EXN_ID: Foo
-      }
-    });
+    throw {
+      RE_EXN_ID: Foo,
+      Error: new Error()
+    };
   }
   try {
     return test(n - 1 | 0);
@@ -22,9 +21,7 @@ function test(n) {
     if (exn.RE_EXN_ID === Foo) {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -42,9 +39,7 @@ function read_lines(inc) {
       if (exn.RE_EXN_ID === "End_of_file") {
         l = undefined;
       } else {
-        throw new Error(exn.RE_EXN_ID, {
-          cause: exn
-        });
+        throw exn;
       }
     }
     if (l === undefined) {
@@ -70,9 +65,7 @@ function read_lines2(inc) {
       if (exn.RE_EXN_ID === "End_of_file") {
         return List.rev(acc);
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     _acc = {
       hd: l,
@@ -95,9 +88,7 @@ function read_lines3(inc) {
       if (exn.RE_EXN_ID === "End_of_file") {
         return List.rev(acc);
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   return loop(/* [] */0);
diff --git a/jscomp/test/gpr_2316_test.js b/jscomp/test/gpr_2316_test.js
index aa33122ecb..f9c22395bd 100644
--- a/jscomp/test/gpr_2316_test.js
+++ b/jscomp/test/gpr_2316_test.js
@@ -30,20 +30,17 @@ function eq(loc, x, y) {
 let y;
 
 try {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "boo"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "boo",
+    Error: new Error()
+  };
 } catch (raw_msg) {
   let msg = Caml_js_exceptions.internalToOCamlException(raw_msg);
   if (msg.RE_EXN_ID === "Failure") {
     y = msg._1;
   } else {
-    throw new Error(msg.RE_EXN_ID, {
-      cause: msg
-    });
+    throw msg;
   }
 }
 
@@ -52,20 +49,17 @@ let x;
 let exit = 0;
 
 try {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "boo"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "boo",
+    Error: new Error()
+  };
 } catch (raw_msg$1) {
   let msg$1 = Caml_js_exceptions.internalToOCamlException(raw_msg$1);
   if (msg$1.RE_EXN_ID === "Failure") {
     x = msg$1._1;
   } else {
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
diff --git a/jscomp/test/gpr_2682_test.js b/jscomp/test/gpr_2682_test.js
index 4b85655c95..1c07be7aca 100644
--- a/jscomp/test/gpr_2682_test.js
+++ b/jscomp/test/gpr_2682_test.js
@@ -46,16 +46,15 @@ let f3 = (()=>true);
 let bbbb = f3();
 
 if (!bbbb) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_2682_test.res",
-        52,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_2682_test.res",
+      52,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 exports.sum = sum;
diff --git a/jscomp/test/gpr_3877_test.js b/jscomp/test/gpr_3877_test.js
index 2e8759406b..27c66d7aef 100644
--- a/jscomp/test/gpr_3877_test.js
+++ b/jscomp/test/gpr_3877_test.js
@@ -21,29 +21,27 @@ let a = "good response";
 let b = "bad response";
 
 if (a !== "good response") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_3877_test.res",
-        26,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_3877_test.res",
+      26,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 if (b !== "bad response") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_3877_test.res",
-        27,
-        0
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_3877_test.res",
+      27,
+      0
+    ],
+    Error: new Error()
+  };
 }
 
 exports.test = test;
diff --git a/jscomp/test/gpr_3980_test.js b/jscomp/test/gpr_3980_test.js
index 3509224e47..3dc94cb04b 100644
--- a/jscomp/test/gpr_3980_test.js
+++ b/jscomp/test/gpr_3980_test.js
@@ -7,45 +7,42 @@ let match = 1;
 
 if (match !== undefined) {
   if (match !== 1) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "gpr_3980_test.res",
-          15,
-          7
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "gpr_3980_test.res",
+        15,
+        7
+      ],
+      Error: new Error()
+    };
   }
   let match$1 = 1;
   if (match$1 !== 1) {
     if (match$1 !== 2) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "gpr_3980_test.res",
-            13,
-            9
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "gpr_3980_test.res",
+          13,
+          9
+        ],
+        Error: new Error()
+      };
     }
     Js_math.floor(1);
   }
   
 } else {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_3980_test.res",
-        15,
-        7
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_3980_test.res",
+      15,
+      7
+    ],
+    Error: new Error()
+  };
 }
 
 /*  Not a pure module */
diff --git a/jscomp/test/gpr_405_test.js b/jscomp/test/gpr_405_test.js
index 3c406084b4..07aa61fba2 100644
--- a/jscomp/test/gpr_405_test.js
+++ b/jscomp/test/gpr_405_test.js
@@ -19,9 +19,7 @@ function Make(funarg) {
       if (exn.RE_EXN_ID === "Not_found") {
         return false;
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   let min_cutset = (gr, first_node) => {
@@ -37,28 +35,26 @@ function Make(funarg) {
     };
     let step2 = (top, rest_of_stack) => {
       if (find_default(already_processed, top)) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "gpr_405_test.res",
-              40,
-              6
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "gpr_405_test.res",
+            40,
+            6
+          ],
+          Error: new Error()
+        };
       }
       if (find_default(on_the_stack, top)) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "gpr_405_test.res",
-              41,
-              6
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "gpr_405_test.res",
+            41,
+            6
+          ],
+          Error: new Error()
+        };
       }
       H.add(on_the_stack, top, true);
       H.add(n_labels, top, counter.contents);
@@ -96,12 +92,11 @@ function Make(funarg) {
           H.add(l_labels, top$1, 0);
         }
         if (H.find(l_labels, top$1) > H.find(n_labels, top$1)) {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Graph.Mincut: graph not reducible"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Graph.Mincut: graph not reducible",
+            Error: new Error()
+          };
         }
         if (!rest_of_stack$1) {
           return cut_set.contents;
diff --git a/jscomp/test/gpr_4632.js b/jscomp/test/gpr_4632.js
index ec0408651d..fa3f84ae3c 100644
--- a/jscomp/test/gpr_4632.js
+++ b/jscomp/test/gpr_4632.js
@@ -21,16 +21,15 @@ let T0 = {
   tail: T0_tail
 };
 
-throw new Error("Match_failure", {
-  cause: {
-    RE_EXN_ID: "Match_failure",
-    _1: [
-      "gpr_4632.res",
-      12,
-      6
-    ]
-  }
-});
+throw {
+  RE_EXN_ID: "Match_failure",
+  _1: [
+    "gpr_4632.res",
+    12,
+    6
+  ],
+  Error: new Error()
+};
 
 exports.T0 = T0;
 exports.T1 = T1;
diff --git a/jscomp/test/gpr_5557.js b/jscomp/test/gpr_5557.js
index 0ca3201b67..54715699d9 100644
--- a/jscomp/test/gpr_5557.js
+++ b/jscomp/test/gpr_5557.js
@@ -6,16 +6,15 @@ function isA(c) {
   if (c === 97) {
     return true;
   }
-  throw new Error("Match_failure", {
-    cause: {
-      RE_EXN_ID: "Match_failure",
-      _1: [
-        "gpr_5557.res",
-        5,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Match_failure",
+    _1: [
+      "gpr_5557.res",
+      5,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let h = /* 'a' */97;
diff --git a/jscomp/test/gpr_858_unit2_test.js b/jscomp/test/gpr_858_unit2_test.js
index 8485cff5a8..4ca3b4244e 100644
--- a/jscomp/test/gpr_858_unit2_test.js
+++ b/jscomp/test/gpr_858_unit2_test.js
@@ -19,16 +19,15 @@ for (let i = 1; i <= 2; ++i) {
     if (i === n) {
       return;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "gpr_858_unit2_test.res",
-          6,
-          13
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "gpr_858_unit2_test.res",
+        6,
+        13
+      ],
+      Error: new Error()
+    };
   };
   f(0, i);
 }
diff --git a/jscomp/test/gpr_974_test.js b/jscomp/test/gpr_974_test.js
index 0c7ede290d..97b799e72a 100644
--- a/jscomp/test/gpr_974_test.js
+++ b/jscomp/test/gpr_974_test.js
@@ -5,42 +5,39 @@ let Caml_obj = require("../../lib/js/caml_obj.js");
 let Caml_option = require("../../lib/js/caml_option.js");
 
 if (!Caml_obj.equal(Caml_option.nullable_to_opt(""), "")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_974_test.res",
-        2,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_974_test.res",
+      2,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Caml_option.undefined_to_opt(""), "")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_974_test.res",
-        3,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_974_test.res",
+      3,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(Caml_option.null_to_opt(""), "")) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "gpr_974_test.res",
-        4,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "gpr_974_test.res",
+      4,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 /*  Not a pure module */
diff --git a/jscomp/test/inline_map2_test.js b/jscomp/test/inline_map2_test.js
index f9d8d4da7c..663e15c663 100644
--- a/jscomp/test/inline_map2_test.js
+++ b/jscomp/test/inline_map2_test.js
@@ -41,12 +41,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r._4;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let lr = l._3;
       let ld = l._2;
@@ -58,12 +57,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, ld, lr._0), lr._1, lr._2, create(lr._3, x, d, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -76,12 +74,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let rr = r._3;
     let rd = r._2;
@@ -93,12 +90,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, x, d, rl._0), rl._1, rl._2, create(rl._3, rv, rd, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   };
   let is_empty = x => {
     if (typeof x !== "object") {
@@ -142,11 +138,10 @@ function Make(Ord) {
     while (true) {
       let x_ = _x_;
       if (typeof x_ !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = Ord.compare(x, x_._1);
       if (c === 0) {
@@ -174,11 +169,10 @@ function Make(Ord) {
     while (true) {
       let x = _x;
       if (typeof x !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = x._0;
       if (typeof l !== "object") {
@@ -195,11 +189,10 @@ function Make(Ord) {
     while (true) {
       let x = _x;
       if (typeof x !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = x._3;
       if (typeof r !== "object") {
@@ -214,12 +207,11 @@ function Make(Ord) {
   };
   let remove_min_binding = x => {
     if (typeof x !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = x._0;
     if (typeof l !== "object") {
@@ -439,16 +431,15 @@ function Make(Ord) {
       
     }
     if (typeof s2 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "inline_map2_test.res",
-            359,
-            11
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "inline_map2_test.res",
+          359,
+          11
+        ],
+        Error: new Error()
+      };
     }
     let v2 = s2._1;
     let match$1 = split(v2, s1);
@@ -675,12 +666,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r._4;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l._3;
     let ld = l._2;
@@ -692,12 +682,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr._0), lr._1, lr._2, create(lr._3, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -710,12 +699,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r._3;
   let rd = r._2;
@@ -727,12 +715,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl._0), rl._1, rl._2, create(rl._3, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty(x) {
@@ -779,11 +766,10 @@ function find(x, _x_) {
   while (true) {
     let x_ = _x_;
     if (typeof x_ !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, x_._1);
     if (c === 0) {
@@ -813,11 +799,10 @@ function min_binding(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = x._0;
     if (typeof l !== "object") {
@@ -835,11 +820,10 @@ function max_binding(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = x._3;
     if (typeof r !== "object") {
@@ -855,12 +839,11 @@ function max_binding(_x) {
 
 function remove_min_binding(x) {
   if (typeof x !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = x._0;
   if (typeof l !== "object") {
@@ -1094,16 +1077,15 @@ function merge(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "inline_map2_test.res",
-          359,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "inline_map2_test.res",
+        359,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2._1;
   let match$1 = split(v2, s1);
@@ -1366,12 +1348,11 @@ function bal$1(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r._4;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l._3;
     let ld = l._2;
@@ -1383,12 +1364,11 @@ function bal$1(l, x, d, r) {
     if (typeof lr === "object") {
       return create$1(create$1(ll, lv, ld, lr._0), lr._1, lr._2, create$1(lr._3, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -1401,12 +1381,11 @@ function bal$1(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r._3;
   let rd = r._2;
@@ -1418,12 +1397,11 @@ function bal$1(l, x, d, r) {
   if (typeof rl === "object") {
     return create$1(create$1(l, x, d, rl._0), rl._1, rl._2, create$1(rl._3, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty$1(x) {
@@ -1470,11 +1448,10 @@ function find$1(x, _x_) {
   while (true) {
     let x_ = _x_;
     if (typeof x_ !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.string_compare(x, x_._1);
     if (c === 0) {
@@ -1504,11 +1481,10 @@ function min_binding$1(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = x._0;
     if (typeof l !== "object") {
@@ -1526,11 +1502,10 @@ function max_binding$1(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = x._3;
     if (typeof r !== "object") {
@@ -1546,12 +1521,11 @@ function max_binding$1(_x) {
 
 function remove_min_binding$1(x) {
   if (typeof x !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = x._0;
   if (typeof l !== "object") {
@@ -1785,16 +1759,15 @@ function merge$1(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "inline_map2_test.res",
-          359,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "inline_map2_test.res",
+        359,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2._1;
   let match$1 = split$1(v2, s1);
diff --git a/jscomp/test/inline_map_demo.js b/jscomp/test/inline_map_demo.js
index 10ebfd5494..cfdd7e8fff 100644
--- a/jscomp/test/inline_map_demo.js
+++ b/jscomp/test/inline_map_demo.js
@@ -33,16 +33,15 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r._4;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "inline_map_demo.res",
-            41,
-            15
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "inline_map_demo.res",
+          41,
+          15
+        ],
+        Error: new Error()
+      };
     }
     let lr = l._3;
     let ld = l._2;
@@ -54,16 +53,15 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr._0), lr._1, lr._2, create(lr._3, x, d, r));
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "inline_map_demo.res",
-          47,
-          19
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "inline_map_demo.res",
+        47,
+        19
+      ],
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -76,16 +74,15 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "inline_map_demo.res",
-          55,
-          15
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "inline_map_demo.res",
+        55,
+        15
+      ],
+      Error: new Error()
+    };
   }
   let rr = r._3;
   let rd = r._2;
@@ -97,16 +94,15 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl._0), rl._1, rl._2, create(rl._3, rv, rd, rr));
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "inline_map_demo.res",
-        61,
-        19
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "inline_map_demo.res",
+      61,
+      19
+    ],
+    Error: new Error()
+  };
 }
 
 function add(x, data, tree) {
@@ -171,11 +167,10 @@ function find(px, _x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(px, x._1);
     if (c === 0) {
diff --git a/jscomp/test/inline_map_test.js b/jscomp/test/inline_map_test.js
index 343b9ec72f..2685f057f3 100644
--- a/jscomp/test/inline_map_test.js
+++ b/jscomp/test/inline_map_test.js
@@ -33,12 +33,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r._4;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l._3;
     let ld = l._2;
@@ -50,12 +49,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr._0), lr._1, lr._2, create(lr._3, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -68,12 +66,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r._3;
   let rd = r._2;
@@ -85,12 +82,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl._0), rl._1, rl._2, create(rl._3, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, x_) {
@@ -129,11 +125,10 @@ function find(x, _x_) {
   while (true) {
     let x_ = _x_;
     if (typeof x_ !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, x_._1);
     if (c === 0) {
diff --git a/jscomp/test/inline_record_test.js b/jscomp/test/inline_record_test.js
index b6e71324b1..9346f7a9f7 100644
--- a/jscomp/test/inline_record_test.js
+++ b/jscomp/test/inline_record_test.js
@@ -63,16 +63,15 @@ let tmp;
 if (A0 === A0) {
   tmp = 3;
 } else {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "inline_record_test.res",
-        47,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "inline_record_test.res",
+      47,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 eq("File \"inline_record_test.res\", line 44, characters 2-9", tmp, 3);
@@ -107,16 +106,15 @@ let tmp$1;
 if (v4.TAG === "A0") {
   tmp$1 = v4.x;
 } else {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "inline_record_test.res",
-        74,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "inline_record_test.res",
+      74,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 eq("File \"inline_record_test.res\", line 71, characters 2-9", tmp$1, 11);
@@ -124,16 +122,15 @@ eq("File \"inline_record_test.res\", line 71, characters 2-9", tmp$1, 11);
 let tmp$2;
 
 if (v5.TAG === "A0") {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "inline_record_test.res",
-        83,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "inline_record_test.res",
+      83,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 tmp$2 = v5.z;
@@ -167,16 +164,15 @@ let tmp$3;
 if (v6.RE_EXN_ID === A4) {
   tmp$3 = v6.x;
 } else {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "inline_record_test.res",
-        108,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "inline_record_test.res",
+      108,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 eq("File \"inline_record_test.res\", line 105, characters 2-9", tmp$3, 11);
diff --git a/jscomp/test/int64_string_test.js b/jscomp/test/int64_string_test.js
index c1ce0329b6..306f2c2b00 100644
--- a/jscomp/test/int64_string_test.js
+++ b/jscomp/test/int64_string_test.js
@@ -1307,30 +1307,28 @@ let random_data = {
 Belt_List.forEach(random_data, u => {
   if (u) {
     if (u.tl) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "int64_string_test.res",
-            191,
-            9
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "int64_string_test.res",
+          191,
+          9
+        ],
+        Error: new Error()
+      };
     }
     let match = u.hd;
     return eq("File \"int64_string_test.res\", line 190, characters 25-32", Caml_int64.to_string(match[0]), match[1]);
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "int64_string_test.res",
-        191,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "int64_string_test.res",
+      191,
+      9
+    ],
+    Error: new Error()
+  };
 });
 
 eq("File \"int64_string_test.res\", line 195, characters 3-10", Caml_int64.to_string([
diff --git a/jscomp/test/int_map.js b/jscomp/test/int_map.js
index 25b7da89be..23f88f7c66 100644
--- a/jscomp/test/int_map.js
+++ b/jscomp/test/int_map.js
@@ -43,12 +43,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -60,12 +59,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -78,12 +76,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -95,12 +92,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty(param) {
@@ -161,11 +157,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -180,11 +175,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -258,11 +252,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -366,11 +359,10 @@ function min_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -406,11 +398,10 @@ function max_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -444,12 +435,11 @@ function max_binding_opt(_param) {
 
 function remove_min_binding(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -753,16 +743,15 @@ function merge$1(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "map.res",
-          552,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "map.res",
+        552,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2.v;
   let match$1 = split(v2, s1);
diff --git a/jscomp/test/internal_unused_test.js b/jscomp/test/internal_unused_test.js
index 006038bf8a..222fa625c9 100644
--- a/jscomp/test/internal_unused_test.js
+++ b/jscomp/test/internal_unused_test.js
@@ -8,11 +8,10 @@ console.log(3);
 let A = /* @__PURE__ */Caml_exceptions.create("Internal_unused_test.P1.A");
 
 function f() {
-  throw new Error(A, {
-    cause: {
-      RE_EXN_ID: A
-    }
-  });
+  throw {
+    RE_EXN_ID: A,
+    Error: new Error()
+  };
 }
 
 let c = 5;
diff --git a/jscomp/test/js_exception_catch_test.js b/jscomp/test/js_exception_catch_test.js
index f4580b614a..7bdbb1b6b4 100644
--- a/jscomp/test/js_exception_catch_test.js
+++ b/jscomp/test/js_exception_catch_test.js
@@ -63,9 +63,7 @@ try {
       _0: true
     }));
   } else {
-    throw new Error(x.RE_EXN_ID, {
-      cause: x
-    });
+    throw x;
   }
 }
 
@@ -121,90 +119,79 @@ function test(f) {
 eq("File \"js_exception_catch_test.res\", line 44, characters 5-12", test(() => {}), "No_error");
 
 eq("File \"js_exception_catch_test.res\", line 45, characters 5-12", test(() => {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }), "Not_found");
 
 eq("File \"js_exception_catch_test.res\", line 46, characters 5-12", test(() => {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "x"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "x",
+    Error: new Error()
+  };
 }), "Invalid_argument");
 
 eq("File \"js_exception_catch_test.res\", line 47, characters 5-12", test(() => {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: ""
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "",
+    Error: new Error()
+  };
 }), "Invalid_any");
 
 eq("File \"js_exception_catch_test.res\", line 48, characters 5-12", test(() => {
-  throw new Error(A, {
-    cause: {
-      RE_EXN_ID: A,
-      _1: 2
-    }
-  });
+  throw {
+    RE_EXN_ID: A,
+    _1: 2,
+    Error: new Error()
+  };
 }), "A2");
 
 eq("File \"js_exception_catch_test.res\", line 49, characters 5-12", test(() => {
-  throw new Error(A, {
-    cause: {
-      RE_EXN_ID: A,
-      _1: 3
-    }
-  });
+  throw {
+    RE_EXN_ID: A,
+    _1: 3,
+    Error: new Error()
+  };
 }), "A_any");
 
 eq("File \"js_exception_catch_test.res\", line 50, characters 5-12", test(() => {
-  throw new Error(B, {
-    cause: {
-      RE_EXN_ID: B
-    }
-  });
+  throw {
+    RE_EXN_ID: B,
+    Error: new Error()
+  };
 }), "B");
 
 eq("File \"js_exception_catch_test.res\", line 51, characters 5-12", test(() => {
-  throw new Error(C, {
-    cause: {
-      RE_EXN_ID: C,
-      _1: 1,
-      _2: 2
-    }
-  });
+  throw {
+    RE_EXN_ID: C,
+    _1: 1,
+    _2: 2,
+    Error: new Error()
+  };
 }), "C");
 
 eq("File \"js_exception_catch_test.res\", line 52, characters 5-12", test(() => {
-  throw new Error(C, {
-    cause: {
-      RE_EXN_ID: C,
-      _1: 0,
-      _2: 2
-    }
-  });
+  throw {
+    RE_EXN_ID: C,
+    _1: 0,
+    _2: 2,
+    Error: new Error()
+  };
 }), "C_any");
 
 eq("File \"js_exception_catch_test.res\", line 53, characters 5-12", test(() => {
-  throw new Error(new Error("x").RE_EXN_ID, {
-    cause: new Error("x")
-  });
+  throw new Error("x");
 }), "Js_error");
 
 eq("File \"js_exception_catch_test.res\", line 54, characters 5-12", test(() => {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "x"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "x",
+    Error: new Error()
+  };
 }), "Any");
 
 Mt.from_pair_suites("Js_exception_catch_test", suites.contents);
diff --git a/jscomp/test/js_json_test.js b/jscomp/test/js_json_test.js
index e0959fb9ca..54f2384053 100644
--- a/jscomp/test/js_json_test.js
+++ b/jscomp/test/js_json_test.js
@@ -91,30 +91,28 @@ add_test("File \"js_json_test.res\", line 22, characters 11-18", () => {
   ty2._0.forEach(x => {
     let ty3 = Js_json.classify(x);
     if (typeof ty3 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "js_json_test.res",
-            38,
-            21
-          ]
-        }
-      });
-    }
-    if (ty3.TAG === "JSONNumber") {
-      return;
-    }
-    throw new Error("Assert_failure", {
-      cause: {
+      throw {
         RE_EXN_ID: "Assert_failure",
         _1: [
           "js_json_test.res",
           38,
           21
-        ]
-      }
-    });
+        ],
+        Error: new Error()
+      };
+    }
+    if (ty3.TAG === "JSONNumber") {
+      return;
+    }
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "js_json_test.res",
+        38,
+        21
+      ],
+      Error: new Error()
+    };
   });
   return {
     TAG: "Ok",
@@ -235,16 +233,15 @@ function option_get(x) {
   if (x !== undefined) {
     return Caml_option.valFromOption(x);
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "js_json_test.res",
-        113,
-        12
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "js_json_test.res",
+      113,
+      12
+    ],
+    Error: new Error()
+  };
 }
 
 let dict = {};
diff --git a/jscomp/test/lazy_test.js b/jscomp/test/lazy_test.js
index 12d3c2aa67..4a346c49b4 100644
--- a/jscomp/test/lazy_test.js
+++ b/jscomp/test/lazy_test.js
@@ -50,20 +50,18 @@ let f005 = CamlinternalLazy.from_fun(() => 6);
 let f006 = CamlinternalLazy.from_fun(() => (() => 3));
 
 let f007 = CamlinternalLazy.from_fun(() => {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 });
 
 function f$1() {
   console.log("hi");
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let f008 = CamlinternalLazy.from_fun(() => f$1());
@@ -183,11 +181,10 @@ Mt.from_pair_suites("Lazy_test", {
                         () => ({
                           TAG: "Ok",
                           _0: !Lazy.is_val(CamlinternalLazy.from_fun(() => {
-                            throw new Error("Not_found", {
-                              cause: {
-                                RE_EXN_ID: "Not_found"
-                              }
-                            });
+                            throw {
+                              RE_EXN_ID: "Not_found",
+                              Error: new Error()
+                            };
                           }))
                         })
                       ],
diff --git a/jscomp/test/libqueue_test.js b/jscomp/test/libqueue_test.js
index 693731383c..11819ab771 100644
--- a/jscomp/test/libqueue_test.js
+++ b/jscomp/test/libqueue_test.js
@@ -41,9 +41,7 @@ function does_raise(f, q) {
     if (exn.RE_EXN_ID === Queue.Empty) {
       return true;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -54,16 +52,15 @@ let q = {
 };
 
 if (!(to_list(q) === /* [] */0 && q.length === 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        30,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      30,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(1, q);
@@ -72,16 +69,15 @@ if (!(Caml_obj.equal(to_list(q), {
     hd: 1,
     tl: /* [] */0
   }) && q.length === 1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        32,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      32,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(2, q);
@@ -93,16 +89,15 @@ if (!(Caml_obj.equal(to_list(q), {
       tl: /* [] */0
     }
   }) && q.length === 2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        34,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      34,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(3, q);
@@ -117,16 +112,15 @@ if (!(Caml_obj.equal(to_list(q), {
       }
     }
   }) && q.length === 3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        36,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      36,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(4, q);
@@ -144,29 +138,27 @@ if (!(Caml_obj.equal(to_list(q), {
       }
     }
   }) && q.length === 4)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        38,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      38,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        39,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      39,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(to_list(q), {
@@ -179,29 +171,27 @@ if (!(Caml_obj.equal(to_list(q), {
       }
     }
   }) && q.length === 3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        40,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      40,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        41,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      41,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(to_list(q), {
@@ -211,84 +201,78 @@ if (!(Caml_obj.equal(to_list(q), {
       tl: /* [] */0
     }
   }) && q.length === 2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        42,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      42,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        43,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      43,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(Caml_obj.equal(to_list(q), {
     hd: 4,
     tl: /* [] */0
   }) && q.length === 1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        44,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      44,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q) !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        45,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      45,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!(to_list(q) === /* [] */0 && q.length === 0)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        46,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      46,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.take, q)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        47,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      47,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$1 = {
@@ -300,70 +284,65 @@ let q$1 = {
 Queue.add(1, q$1);
 
 if (Queue.take(q$1) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        53,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      53,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.take, q$1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        54,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      54,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(2, q$1);
 
 if (Queue.take(q$1) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        56,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      56,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.take, q$1)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        57,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      57,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        58,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      58,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$2 = {
@@ -375,150 +354,139 @@ let q$2 = {
 Queue.add(1, q$2);
 
 if (Queue.peek(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        64,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      64,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(2, q$2);
 
 if (Queue.peek(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        66,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      66,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(3, q$2);
 
 if (Queue.peek(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        68,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      68,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.peek(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        69,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      69,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q$2) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        70,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      70,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.peek(q$2) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        71,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      71,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q$2) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        72,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      72,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.peek(q$2) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        73,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      73,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (Queue.take(q$2) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        74,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      74,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.peek, q$2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        75,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      75,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.peek, q$2)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        76,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      76,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$3 = {
@@ -534,29 +502,27 @@ for (let i = 1; i <= 10; ++i) {
 Queue.clear(q$3);
 
 if (q$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        85,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      85,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!does_raise(Queue.take, q$3)) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        86,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      86,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(q$3, {
@@ -564,31 +530,29 @@ if (!Caml_obj.equal(q$3, {
     first: "Nil",
     last: "Nil"
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        87,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      87,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.add(42, q$3);
 
 if (Queue.take(q$3) !== 42) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        89,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      89,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1 = {
@@ -634,16 +598,15 @@ if (!Caml_obj.equal(to_list(q1), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        98,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      98,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2), {
@@ -677,72 +640,67 @@ if (!Caml_obj.equal(to_list(q2), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        99,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      99,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q1.length !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        100,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      100,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2.length !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        101,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      101,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 for (let i$2 = 1; i$2 <= 10; ++i$2) {
   if (Queue.take(q1) !== i$2) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          103,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        103,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
 
 for (let i$3 = 1; i$3 <= 10; ++i$3) {
   if (Queue.take(q2) !== i$3) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          106,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        106,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
@@ -754,99 +712,92 @@ let q$4 = {
 };
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        112,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      112,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 for (let i$4 = 1; i$4 <= 10; ++i$4) {
   Queue.add(i$4, q$4);
   if (q$4.length !== i$4) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          115,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        115,
+        4
+      ],
+      Error: new Error()
+    };
   }
   if (q$4.length === 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          116,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        116,
+        4
+      ],
+      Error: new Error()
+    };
   }
   
 }
 
 for (let i$5 = 10; i$5 >= 1; --i$5) {
   if (q$4.length !== i$5) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          119,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        119,
+        4
+      ],
+      Error: new Error()
+    };
   }
   if (q$4.length === 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          120,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        120,
+        4
+      ],
+      Error: new Error()
+    };
   }
   Queue.take(q$4);
 }
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        123,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      123,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        124,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      124,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q$5 = {
@@ -865,16 +816,15 @@ let i$7 = {
 
 Queue.iter(j => {
   if (i$7.contents !== j) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "libqueue_test.res",
-          134,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "libqueue_test.res",
+        134,
+        4
+      ],
+      Error: new Error()
+    };
   }
   i$7.contents = i$7.contents + 1 | 0;
 }, q$5);
@@ -892,109 +842,101 @@ let q2$1 = {
 };
 
 if (q1$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        141,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      141,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$1) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        142,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      142,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        143,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      143,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q2$1) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        144,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      144,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.transfer(q1$1, q2$1);
 
 if (q1$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        146,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      146,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$1) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        147,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      147,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$1.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        148,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      148,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q2$1) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        149,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      149,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$2 = {
@@ -1014,16 +956,15 @@ for (let i$8 = 1; i$8 <= 4; ++i$8) {
 }
 
 if (q1$2.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        157,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      157,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q1$2), {
@@ -1039,83 +980,77 @@ if (!Caml_obj.equal(to_list(q1$2), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        158,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      158,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$2.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        159,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      159,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q2$2) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        160,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      160,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.transfer(q1$2, q2$2);
 
 if (q1$2.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        162,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      162,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$2) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        163,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      163,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$2.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        164,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      164,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2$2), {
@@ -1131,16 +1066,15 @@ if (!Caml_obj.equal(to_list(q2$2), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        165,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      165,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$3 = {
@@ -1160,42 +1094,39 @@ for (let i$9 = 5; i$9 <= 8; ++i$9) {
 }
 
 if (q1$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        173,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      173,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$3) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        174,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      174,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$3.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        175,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      175,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2$3), {
@@ -1211,57 +1142,53 @@ if (!Caml_obj.equal(to_list(q2$3), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        176,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      176,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.transfer(q1$3, q2$3);
 
 if (q1$3.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        178,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      178,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$3) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        179,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      179,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$3.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        180,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      180,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2$3), {
@@ -1277,16 +1204,15 @@ if (!Caml_obj.equal(to_list(q2$3), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        181,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      181,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let q1$4 = {
@@ -1310,16 +1236,15 @@ for (let i$11 = 5; i$11 <= 8; ++i$11) {
 }
 
 if (q1$4.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        192,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      192,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q1$4), {
@@ -1335,29 +1260,27 @@ if (!Caml_obj.equal(to_list(q1$4), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        193,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      193,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$4.length !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        194,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      194,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2$4), {
@@ -1373,57 +1296,53 @@ if (!Caml_obj.equal(to_list(q2$4), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        195,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      195,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 Queue.transfer(q1$4, q2$4);
 
 if (q1$4.length !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        197,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      197,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (to_list(q1$4) !== /* [] */0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        198,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      198,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (q2$4.length !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        199,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      199,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(to_list(q2$4), {
@@ -1451,16 +1370,15 @@ if (!Caml_obj.equal(to_list(q2$4), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "libqueue_test.res",
-        200,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "libqueue_test.res",
+      200,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 console.log("OK");
diff --git a/jscomp/test/map_find_test.js b/jscomp/test/map_find_test.js
index fd645f38c2..584e25c7e1 100644
--- a/jscomp/test/map_find_test.js
+++ b/jscomp/test/map_find_test.js
@@ -33,12 +33,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -50,12 +49,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -68,12 +66,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -85,12 +82,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, param) {
@@ -143,11 +139,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -212,12 +207,11 @@ function bal$1(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -229,12 +223,11 @@ function bal$1(l, x, d, r) {
     if (typeof lr === "object") {
       return create$1(create$1(ll, lv, ld, lr.l), lr.v, lr.d, create$1(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -247,12 +240,11 @@ function bal$1(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -264,12 +256,11 @@ function bal$1(l, x, d, r) {
   if (typeof rl === "object") {
     return create$1(create$1(l, x, d, rl.l), rl.v, rl.d, create$1(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add$1(x, data, param) {
@@ -322,11 +313,10 @@ function find$1(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.string_compare(x, param.v);
     if (c === 0) {
diff --git a/jscomp/test/map_test.js b/jscomp/test/map_test.js
index bd37173302..72a78eeacc 100644
--- a/jscomp/test/map_test.js
+++ b/jscomp/test/map_test.js
@@ -51,12 +51,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -68,12 +67,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -86,12 +84,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -103,12 +100,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty(param) {
@@ -169,11 +165,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -188,11 +183,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -266,11 +260,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -374,11 +367,10 @@ function min_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -414,11 +406,10 @@ function max_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -452,12 +443,11 @@ function max_binding_opt(_param) {
 
 function remove_min_binding(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -761,16 +751,15 @@ function merge$1(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "map.res",
-          552,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "map.res",
+        552,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2.v;
   let match$1 = split(v2, s1);
@@ -1045,12 +1034,11 @@ function bal$1(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -1062,12 +1050,11 @@ function bal$1(l, x, d, r) {
     if (typeof lr === "object") {
       return create$1(create$1(ll, lv, ld, lr.l), lr.v, lr.d, create$1(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -1080,12 +1067,11 @@ function bal$1(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -1097,12 +1083,11 @@ function bal$1(l, x, d, r) {
   if (typeof rl === "object") {
     return create$1(create$1(l, x, d, rl.l), rl.v, rl.d, create$1(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty$1(param) {
@@ -1163,11 +1148,10 @@ function find$1(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.string_compare(x, param.v);
     if (c === 0) {
@@ -1182,11 +1166,10 @@ function find_first$1(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -1260,11 +1243,10 @@ function find_last$1(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -1368,11 +1350,10 @@ function min_binding$1(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -1408,11 +1389,10 @@ function max_binding$1(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -1446,12 +1426,11 @@ function max_binding_opt$1(_param) {
 
 function remove_min_binding$1(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -1755,16 +1734,15 @@ function merge$3(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "map.res",
-          552,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "map.res",
+        552,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2.v;
   let match$1 = split$1(v2, s1);
diff --git a/jscomp/test/mario_game.js b/jscomp/test/mario_game.js
index f1dc0788a9..778211b4a8 100644
--- a/jscomp/test/mario_game.js
+++ b/jscomp/test/mario_game.js
@@ -1484,12 +1484,11 @@ function game_win(ctx) {
   ctx.fillStyle = "white";
   ctx.font = "20px 'Press Start 2P'";
   ctx.fillText("You win!", 180, 128);
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "Game over."
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "Game over.",
+    Error: new Error()
+  };
 }
 
 function game_loss(ctx) {
@@ -1499,12 +1498,11 @@ function game_loss(ctx) {
   ctx.fillStyle = "white";
   ctx.font = "20px 'Press Start 2P'";
   ctx.fillText("GAME OVER. You lose!", 60, 128);
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "Game over."
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "Game over.",
+    Error: new Error()
+  };
 }
 
 let Draw = {
@@ -2464,12 +2462,11 @@ function choose_enemy_typ(typ) {
     case 2 :
       return "Goomba";
     default:
-      throw new Error("Failure", {
-        cause: {
-          RE_EXN_ID: "Failure",
-          _1: "Shouldn't reach here"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Failure",
+        _1: "Shouldn't reach here",
+        Error: new Error()
+      };
   }
 }
 
@@ -2489,12 +2486,11 @@ function choose_sblock_typ(typ) {
     case 4 :
       return "Ground";
     default:
-      throw new Error("Failure", {
-        cause: {
-          RE_EXN_ID: "Failure",
-          _1: "Shouldn't reach here"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Failure",
+        _1: "Shouldn't reach here",
+        Error: new Error()
+      };
   }
 }
 
@@ -3005,12 +3001,11 @@ function choose_block_pattern(blockw, blockh, cbx, cby, prob) {
         tl: /* [] */0
       };
     default:
-      throw new Error("Failure", {
-        cause: {
-          RE_EXN_ID: "Failure",
-          _1: "Shouldn't reach here"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Failure",
+        _1: "Shouldn't reach here",
+        Error: new Error()
+      };
   }
 }
 
@@ -3279,12 +3274,11 @@ function load(param) {
     canvas = el;
   } else {
     console.log("cant find canvas " + canvas_id);
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "fail"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "fail",
+      Error: new Error()
+    };
   }
   let context = canvas.getContext("2d");
   document.addEventListener("keydown", keydown, true);
diff --git a/jscomp/test/noassert.js b/jscomp/test/noassert.js
index 249a4ce2fb..9626fa7296 100644
--- a/jscomp/test/noassert.js
+++ b/jscomp/test/noassert.js
@@ -3,16 +3,15 @@
 
 
 function f() {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "noassert.res",
-        1,
-        14
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "noassert.res",
+      1,
+      14
+    ],
+    Error: new Error()
+  };
 }
 
 function h() {
diff --git a/jscomp/test/ocaml_re_test.js b/jscomp/test/ocaml_re_test.js
index 2b1ff3c81c..1493e8b236 100644
--- a/jscomp/test/ocaml_re_test.js
+++ b/jscomp/test/ocaml_re_test.js
@@ -318,12 +318,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -335,12 +334,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -353,12 +351,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -370,12 +367,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, param) {
@@ -519,12 +515,11 @@ function bal$1(l, v, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let lv = l.v;
@@ -535,12 +530,11 @@ function bal$1(l, v, r) {
     if (typeof lr === "object") {
       return create$1(create$1(ll, lv, lr.l), lr.v, create$1(lr.r, v, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -552,12 +546,11 @@ function bal$1(l, v, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rv = r.v;
@@ -568,12 +561,11 @@ function bal$1(l, v, r) {
   if (typeof rl === "object") {
     return create$1(create$1(l, v, rl.l), rl.v, create$1(rl.r, rv, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Set.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Set.bal",
+    Error: new Error()
+  };
 }
 
 function add$1(x, param) {
@@ -1072,16 +1064,15 @@ function split_at_match_rec(_l$p, _x) {
           ];
       }
     } else {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "ocaml_re_test.res",
-            815,
-            16
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "ocaml_re_test.res",
+          815,
+          16
+        ],
+        Error: new Error()
+      };
     }
   };
 }
@@ -1512,9 +1503,7 @@ function find_state(re, desc) {
       Re_automata_State.Table.add(re.states, desc, st);
       return st;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -1594,9 +1583,7 @@ function final(info, st, cat) {
       };
       return res;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -1616,9 +1603,7 @@ function find_initial_state(re, cat) {
       };
       return st;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -1721,11 +1706,10 @@ function trans_set(cache, cm, s) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = compare(v, param.v);
       if (c === 0) {
@@ -1741,9 +1725,7 @@ function trans_set(cache, cm, s) {
       cache.contents = add(v, l, cache.contents);
       return l;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -1882,16 +1864,15 @@ function colorize(c, regexp) {
             _regexp = regexp._1;
             continue;
           default:
-            throw new Error("Assert_failure", {
-              cause: {
-                RE_EXN_ID: "Assert_failure",
-                _1: [
-                  "ocaml_re_test.res",
-                  2168,
-                  8
-                ]
-              }
-            });
+            throw {
+              RE_EXN_ID: "Assert_failure",
+              _1: [
+                "ocaml_re_test.res",
+                2168,
+                8
+              ],
+              Error: new Error()
+            };
         }
       }
     };
@@ -2492,16 +2473,15 @@ function translate(ids, kind, _ign_group, ign_case, _greedy, pos, cache, c, _x)
             match$5[1]
           ];
         default:
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "ocaml_re_test.res",
-                2402,
-                80
-              ]
-            }
-          });
+          throw {
+            RE_EXN_ID: "Assert_failure",
+            _1: [
+              "ocaml_re_test.res",
+              2402,
+              80
+            ],
+            Error: new Error()
+          };
       }
     }
   };
@@ -2535,30 +2515,28 @@ function case_insens(s) {
 
 function as_set(x) {
   if (typeof x !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "ocaml_re_test.res",
-          2437,
-          11
-        ]
-      }
-    });
-  }
-  if (x.TAG === "Set") {
-    return x._0;
-  }
-  throw new Error("Assert_failure", {
-    cause: {
+    throw {
       RE_EXN_ID: "Assert_failure",
       _1: [
         "ocaml_re_test.res",
         2437,
         11
-      ]
-    }
-  });
+      ],
+      Error: new Error()
+    };
+  }
+  if (x.TAG === "Set") {
+    return x._0;
+  }
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "ocaml_re_test.res",
+      2437,
+      11
+    ],
+    Error: new Error()
+  };
 }
 
 function handle_case(_ign_case, _x) {
@@ -2756,20 +2734,18 @@ let epsilon = {
 
 function repn(r, i, j) {
   if (i < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Re.repn"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Re.repn",
+      Error: new Error()
+    };
   }
   if (j !== undefined && j < i) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Re.repn"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Re.repn",
+      Error: new Error()
+    };
   }
   return {
     TAG: "Repeat",
@@ -2798,12 +2774,11 @@ function compl(l) {
   if (is_charset(r)) {
     return r;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Re.compl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Re.compl",
+    Error: new Error()
+  };
 }
 
 let any = {
@@ -3153,12 +3128,11 @@ function exec_internal(name, posOpt, lenOpt, groups, re, s) {
   let pos = posOpt !== undefined ? posOpt : 0;
   let len = lenOpt !== undefined ? lenOpt : -1;
   if (pos < 0 || len < -1 || (pos + len | 0) > s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: name
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: name,
+      Error: new Error()
+    };
   }
   let partial = false;
   let slen = s.length;
@@ -3224,19 +3198,17 @@ function exec_internal(name, posOpt, lenOpt, groups, re, s) {
 
 function offset$1(t, i) {
   if (((i << 1) + 1 | 0) >= t.marks.length) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let m1 = Caml_array.get(t.marks, (i << 1));
   if (m1 === -1) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let p1 = Caml_array.get(t.gpos, m1) - 1 | 0;
   let p2 = Caml_array.get(t.gpos, Caml_array.get(t.marks, (i << 1) + 1 | 0)) - 1 | 0;
@@ -3286,12 +3258,11 @@ function posix_class_of_string(x) {
       return xdigit;
     default:
       let s = "Invalid pcre class: " + x;
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: s
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: s,
+        Error: new Error()
+      };
   }
 }
 
@@ -3320,19 +3291,17 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
       for (let j = 0; j < len; ++j) {
         try {
           if (Caml_string.get(s$p, j) !== Caml_string.get(s, i.contents + j | 0)) {
-            throw new Error(Pervasives.Exit, {
-              cause: {
-                RE_EXN_ID: Pervasives.Exit
-              }
-            });
+            throw {
+              RE_EXN_ID: Pervasives.Exit,
+              Error: new Error()
+            };
           }
           
         } catch (exn) {
-          throw new Error(Pervasives.Exit, {
-            cause: {
-              RE_EXN_ID: Pervasives.Exit
-            }
-          });
+          throw {
+            RE_EXN_ID: Pervasives.Exit,
+            Error: new Error()
+          };
         }
       }
       i.contents = i.contents + len | 0;
@@ -3342,9 +3311,7 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
       if (exn$1.RE_EXN_ID === Pervasives.Exit) {
         return false;
       }
-      throw new Error(exn$1.RE_EXN_ID, {
-        cause: exn$1
-      });
+      throw exn$1;
     }
   };
   let get = () => {
@@ -3411,30 +3378,27 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         if (accept(/* ':' */58)) {
           let r = regexp$p(branch());
           if (!accept(/* ')' */41)) {
-            throw new Error(Parse_error, {
-              cause: {
-                RE_EXN_ID: Parse_error
-              }
-            });
+            throw {
+              RE_EXN_ID: Parse_error,
+              Error: new Error()
+            };
           }
           return r;
         }
         if (accept(/* '#' */35)) {
           return comment();
         }
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       let r$1 = regexp$p(branch());
       if (!accept(/* ')' */41)) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       return {
         TAG: "Group",
@@ -3466,11 +3430,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
     }
     if (accept(/* '\\' */92)) {
       if (i.contents === l) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       let c = get();
       switch (c) {
@@ -3484,11 +3447,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         case 55 :
         case 56 :
         case 57 :
-          throw new Error(Not_supported, {
-            cause: {
-              RE_EXN_ID: Not_supported
-            }
-          });
+          throw {
+            RE_EXN_ID: Not_supported,
+            Error: new Error()
+          };
         case 65 :
           return "Beg_of_str";
         case 66 :
@@ -3593,11 +3555,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         case 118 :
         case 120 :
         case 121 :
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         case 122 :
           return "End_of_str";
         default:
@@ -3608,11 +3569,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
       }
     } else {
       if (i.contents === l) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       let c$1 = get();
       if (c$1 >= 64) {
@@ -3623,25 +3583,22 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
               _0: single(c$1)
             };
           }
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         }
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       if (c$1 >= 44) {
         if (c$1 >= 63) {
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         }
         return {
           TAG: "Set",
@@ -3649,11 +3606,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         };
       }
       if (c$1 >= 42) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       return {
         TAG: "Set",
@@ -3683,11 +3639,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         }
         let i$p = Math.imul(10, i$1) + (d$1 - /* '0' */48 | 0) | 0;
         if (i$p < i$1) {
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         }
         _i = i$p;
         continue;
@@ -3712,18 +3667,16 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
     if (i$1 !== undefined) {
       let j = accept(/* ',' */44) ? integer() : i$1;
       if (!accept(/* '}' */125)) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       if (j !== undefined && j < i$1) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       return greedy_mod(repn(r, i$1, j));
     }
@@ -3732,20 +3685,18 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
   };
   let char = () => {
     if (i.contents === l) {
-      throw new Error(Parse_error, {
-        cause: {
-          RE_EXN_ID: Parse_error
-        }
-      });
+      throw {
+        RE_EXN_ID: Parse_error,
+        Error: new Error()
+      };
     }
     let c = get();
     if (c === /* '[' */91) {
       if (accept(/* '=' */61)) {
-        throw new Error(Not_supported, {
-          cause: {
-            RE_EXN_ID: Not_supported
-          }
-        });
+        throw {
+          RE_EXN_ID: Not_supported,
+          Error: new Error()
+        };
       }
       if (accept(/* ':' */58)) {
         let compl$1 = accept(/* '^' */94);
@@ -3794,22 +3745,18 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         } catch (raw_exn) {
           let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
           if (exn.RE_EXN_ID === "Not_found") {
-            throw new Error(Parse_error, {
-              cause: {
-                RE_EXN_ID: Parse_error
-              }
-            });
+            throw {
+              RE_EXN_ID: Parse_error,
+              Error: new Error()
+            };
           }
-          throw new Error(exn.RE_EXN_ID, {
-            cause: exn
-          });
+          throw exn;
         }
         if (!accept_s(":]")) {
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         }
         let posix_class = posix_class_of_string(cls);
         let re = compl$1 ? compl({
@@ -3828,26 +3775,23 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         };
       }
       if (i.contents === l) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       let c$1 = get();
       if (!accept(/* '.' */46)) {
-        throw new Error(Not_supported, {
-          cause: {
-            RE_EXN_ID: Not_supported
-          }
-        });
+        throw {
+          RE_EXN_ID: Not_supported,
+          Error: new Error()
+        };
       }
       if (!accept(/* ']' */93)) {
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          Error: new Error()
+        };
       }
       return {
         NAME: "Char",
@@ -4014,19 +3958,17 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
         case 120 :
         case 121 :
         case 122 :
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
       }
     } else {
       if (c$2 >= 48) {
-        throw new Error(Not_supported, {
-          cause: {
-            RE_EXN_ID: Not_supported
-          }
-        });
+        throw {
+          RE_EXN_ID: Not_supported,
+          Error: new Error()
+        };
       }
       return {
         NAME: "Char",
@@ -4127,11 +4069,10 @@ function parse(multiline, dollar_endonly, dotall, ungreedy, s) {
   };
   let res = regexp$p(branch());
   if (i.contents !== l) {
-    throw new Error(Parse_error, {
-      cause: {
-        RE_EXN_ID: Parse_error
-      }
-    });
+    throw {
+      RE_EXN_ID: Parse_error,
+      Error: new Error()
+    };
   }
   return res;
 }
@@ -4174,17 +4115,15 @@ function exec(rex, pos, s) {
     return substr._0;
   }
   if (substr === "Failed") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let s = "a".repeat(1048575) + "b";
diff --git a/jscomp/test/offset.js b/jscomp/test/offset.js
index 478ed2bf19..457a8bbe5b 100644
--- a/jscomp/test/offset.js
+++ b/jscomp/test/offset.js
@@ -35,12 +35,11 @@ function bal(l, v, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let lv = l.v;
@@ -51,12 +50,11 @@ function bal(l, v, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -68,12 +66,11 @@ function bal(l, v, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rv = r.v;
@@ -84,12 +81,11 @@ function bal(l, v, r) {
   if (typeof rl === "object") {
     return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Set.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Set.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, param) {
@@ -173,11 +169,10 @@ function min_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -207,11 +202,10 @@ function max_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -239,12 +233,11 @@ function max_elt_opt(_param) {
 
 function remove_min_elt(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -658,11 +651,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     let c = Caml.string_compare(x, v);
@@ -678,11 +670,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -744,11 +735,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -955,16 +945,15 @@ function of_list(l) {
             match$4[1]
           ];
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "set.res",
-              691,
-              20
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "set.res",
+            691,
+            20
+          ],
+          Error: new Error()
+        };
       };
       return sub(List.length(l$1), l$1)[0];
     } else {
diff --git a/jscomp/test/pq_test.js b/jscomp/test/pq_test.js
index 55344e6523..ef55e96787 100644
--- a/jscomp/test/pq_test.js
+++ b/jscomp/test/pq_test.js
@@ -40,11 +40,10 @@ let Queue_is_empty = /* @__PURE__ */Caml_exceptions.create("Pq_test.PrioQueue.Qu
 
 function remove_top(x) {
   if (typeof x !== "object") {
-    throw new Error(Queue_is_empty, {
-      cause: {
-        RE_EXN_ID: Queue_is_empty
-      }
-    });
+    throw {
+      RE_EXN_ID: Queue_is_empty,
+      Error: new Error()
+    };
   }
   let left = x._2;
   let tmp = x._3;
@@ -84,11 +83,10 @@ function extract(x) {
       remove_top(x)
     ];
   }
-  throw new Error(Queue_is_empty, {
-    cause: {
-      RE_EXN_ID: Queue_is_empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Queue_is_empty,
+    Error: new Error()
+  };
 }
 
 let PrioQueue = {
diff --git a/jscomp/test/queue_402.js b/jscomp/test/queue_402.js
index c40c62a0f9..edbac77196 100644
--- a/jscomp/test/queue_402.js
+++ b/jscomp/test/queue_402.js
@@ -40,22 +40,20 @@ function add(x, q) {
 
 function peek(q) {
   if (q.length === 0) {
-    throw new Error(Empty, {
-      cause: {
-        RE_EXN_ID: Empty
-      }
-    });
+    throw {
+      RE_EXN_ID: Empty,
+      Error: new Error()
+    };
   }
   return q.tail.next.content;
 }
 
 function take(q) {
   if (q.length === 0) {
-    throw new Error(Empty, {
-      cause: {
-        RE_EXN_ID: Empty
-      }
-    });
+    throw {
+      RE_EXN_ID: Empty,
+      Error: new Error()
+    };
   }
   q.length = q.length - 1 | 0;
   let tail = q.tail;
diff --git a/jscomp/test/raw_hash_tbl_bench.js b/jscomp/test/raw_hash_tbl_bench.js
index 0e1650354a..f8de383cdf 100644
--- a/jscomp/test/raw_hash_tbl_bench.js
+++ b/jscomp/test/raw_hash_tbl_bench.js
@@ -10,16 +10,15 @@ function bench() {
   }
   for (let i$1 = 0; i$1 <= 1000000; ++i$1) {
     if (!Hashtbl.mem(table, i$1)) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "raw_hash_tbl_bench.res",
-            8,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "raw_hash_tbl_bench.res",
+          8,
+          4
+        ],
+        Error: new Error()
+      };
     }
     
   }
diff --git a/jscomp/test/rbset.js b/jscomp/test/rbset.js
index 559c1cfe84..ceb920a14c 100644
--- a/jscomp/test/rbset.js
+++ b/jscomp/test/rbset.js
@@ -265,16 +265,15 @@ function unbalanced_left(x) {
       
     }
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "rbset.res",
-        64,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "rbset.res",
+      64,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function unbalanced_right(x) {
@@ -335,16 +334,15 @@ function unbalanced_right(x) {
       
     }
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "rbset.res",
-        75,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "rbset.res",
+      75,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function lbalance(x1, x2, x3) {
@@ -560,16 +558,15 @@ function add(x, s) {
 
 function remove_min(x) {
   if (typeof x !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "rbset.res",
-          138,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "rbset.res",
+        138,
+        4
+      ],
+      Error: new Error()
+    };
   }
   let c = x._0;
   if (c === "Black") {
@@ -597,16 +594,15 @@ function remove_min(x) {
           false
         ];
       }
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "rbset.res",
-            138,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "rbset.res",
+          138,
+          4
+        ],
+        Error: new Error()
+      };
     }
     
   } else {
diff --git a/jscomp/test/reactDOMRe.js b/jscomp/test/reactDOMRe.js
index e438f9ee76..dee8919f57 100644
--- a/jscomp/test/reactDOMRe.js
+++ b/jscomp/test/reactDOMRe.js
@@ -69,12 +69,11 @@ function hydrateToElementWithClassName(reactElement, className) {
 function hydrateToElementWithId(reactElement, id) {
   let element = document.getElementById(id);
   if (element == null) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "ReactDOMRe.hydrateToElementWithId : no element of id " + (id + " found in the HTML.")
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "ReactDOMRe.hydrateToElementWithId : no element of id " + (id + " found in the HTML."),
+      Error: new Error()
+    };
   }
   ReactDom.hydrate(reactElement, element);
 }
diff --git a/jscomp/test/rec_module_test.js b/jscomp/test/rec_module_test.js
index eeeeb1eb4c..93c8ff239d 100644
--- a/jscomp/test/rec_module_test.js
+++ b/jscomp/test/rec_module_test.js
@@ -214,12 +214,11 @@ function bal(l, v, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let lv = l.v;
@@ -230,12 +229,11 @@ function bal(l, v, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -247,12 +245,11 @@ function bal(l, v, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rv = r.v;
@@ -263,12 +260,11 @@ function bal(l, v, r) {
   if (typeof rl === "object") {
     return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Set.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Set.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, param) {
@@ -352,11 +348,10 @@ function min_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -386,11 +381,10 @@ function max_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -418,12 +412,11 @@ function max_elt_opt(_param) {
 
 function remove_min_elt(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -837,11 +830,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     let c = AAA.compare(x, v);
@@ -857,11 +849,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -923,11 +914,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -1134,16 +1124,15 @@ function of_list(l) {
             match$4[1]
           ];
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "set.res",
-              691,
-              20
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "set.res",
+            691,
+            20
+          ],
+          Error: new Error()
+        };
       };
       return sub(List.length(l$1), l$1)[0];
     } else {
diff --git a/jscomp/test/recmodule.js b/jscomp/test/recmodule.js
index c940c8ea14..f500c27bd8 100644
--- a/jscomp/test/recmodule.js
+++ b/jscomp/test/recmodule.js
@@ -34,16 +34,15 @@ let Adapter = {
 
 function MakeLayer$2(Deps) {
   let presentJson = (json, status) => {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "recmodule.res",
-          60,
-          41
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "recmodule.res",
+        60,
+        41
+      ],
+      Error: new Error()
+    };
   };
   let routes = () => [[
       "/lights",
@@ -108,16 +107,15 @@ let U = Caml_module.init_mod([
 });
 
 function presentJson(json, status) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "recmodule.res",
-        60,
-        41
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "recmodule.res",
+      60,
+      41
+    ],
+    Error: new Error()
+  };
 }
 
 function routes() {
diff --git a/jscomp/test/record_extension_test.js b/jscomp/test/record_extension_test.js
index dedeabf26c..9a01bc12ee 100644
--- a/jscomp/test/record_extension_test.js
+++ b/jscomp/test/record_extension_test.js
@@ -97,32 +97,29 @@ function u(f) {
 }
 
 eq("File \"record_extension_test.res\", line 59, characters 3-10", u(() => {
-  throw new Error(A, {
-    cause: {
-      RE_EXN_ID: A,
-      name: 1,
-      x: 1
-    }
-  });
+  throw {
+    RE_EXN_ID: A,
+    name: 1,
+    x: 1,
+    Error: new Error()
+  };
 }), 2);
 
 eq("File \"record_extension_test.res\", line 60, characters 3-10", u(() => {
-  throw new Error(B, {
-    cause: {
-      RE_EXN_ID: B,
-      _1: 1,
-      _2: 2
-    }
-  });
+  throw {
+    RE_EXN_ID: B,
+    _1: 1,
+    _2: 2,
+    Error: new Error()
+  };
 }), 3);
 
 eq("File \"record_extension_test.res\", line 61, characters 3-10", u(() => {
-  throw new Error(C, {
-    cause: {
-      RE_EXN_ID: C,
-      name: 4
-    }
-  });
+  throw {
+    RE_EXN_ID: C,
+    name: 4,
+    Error: new Error()
+  };
 }), 4);
 
 Mt.from_pair_suites("File \"record_extension_test.res\", line 63, characters 29-36", suites.contents);
diff --git a/jscomp/test/recursive_module.js b/jscomp/test/recursive_module.js
index 70ee5b42ee..25f412c863 100644
--- a/jscomp/test/recursive_module.js
+++ b/jscomp/test/recursive_module.js
@@ -100,9 +100,7 @@ try {
   if (exn.RE_EXN_ID === Lazy.Undefined) {
     tmp = -1;
   } else {
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -173,9 +171,7 @@ try {
   if (exn$1.RE_EXN_ID === "Undefined_recursive_module") {
     tmp$1 = 4;
   } else {
-    throw new Error(exn$1.RE_EXN_ID, {
-      cause: exn$1
-    });
+    throw exn$1;
   }
 }
 
diff --git a/jscomp/test/recursive_records_test.js b/jscomp/test/recursive_records_test.js
index 61816cb5d4..20b542d691 100644
--- a/jscomp/test/recursive_records_test.js
+++ b/jscomp/test/recursive_records_test.js
@@ -68,16 +68,15 @@ function tl_exn(x) {
   if (typeof x === "object") {
     return x.next;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "recursive_records_test.res",
-        49,
-        11
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "recursive_records_test.res",
+      49,
+      11
+    ],
+    Error: new Error()
+  };
 }
 
 eq("File \"recursive_records_test.res\", line 54, characters 5-12", (hd(rec_cell2) + hd(tl_exn(rec_cell2)) | 0) + hd(tl_exn(tl_exn(rec_cell2))) | 0, 9);
diff --git a/jscomp/test/return_check.js b/jscomp/test/return_check.js
index ab7805940a..b4992c4363 100644
--- a/jscomp/test/return_check.js
+++ b/jscomp/test/return_check.js
@@ -18,16 +18,15 @@ function f_undefined(xs, i) {
   if (k !== undefined) {
     return k;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "return_check.res",
-        23,
-        12
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "return_check.res",
+      23,
+      12
+    ],
+    Error: new Error()
+  };
 }
 
 function f_escaped_not(xs, i) {
@@ -60,16 +59,15 @@ function f_null(xs, i) {
   if (k !== null) {
     return k;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "return_check.res",
-        51,
-        12
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "return_check.res",
+      51,
+      12
+    ],
+    Error: new Error()
+  };
 }
 
 function f_null_undefined(xs, i) {
@@ -77,16 +75,15 @@ function f_null_undefined(xs, i) {
   if (!(k == null)) {
     return k;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "return_check.res",
-        59,
-        12
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "return_check.res",
+      59,
+      12
+    ],
+    Error: new Error()
+  };
 }
 
 exports.test = test;
diff --git a/jscomp/test/set_gen.js b/jscomp/test/set_gen.js
index d5e26c887a..26eb922993 100644
--- a/jscomp/test/set_gen.js
+++ b/jscomp/test/set_gen.js
@@ -35,11 +35,10 @@ function min_elt(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = x._0;
     if (typeof l !== "object") {
@@ -54,11 +53,10 @@ function max_elt(_x) {
   while (true) {
     let x = _x;
     if (typeof x !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = x._2;
     if (typeof r !== "object") {
@@ -208,19 +206,17 @@ function check_height_and_diff(x) {
   let hl = check_height_and_diff(x._0);
   let hr = check_height_and_diff(x._2);
   if (h !== (max_int_2(hl, hr) + 1 | 0)) {
-    throw new Error(Height_invariant_broken, {
-      cause: {
-        RE_EXN_ID: Height_invariant_broken
-      }
-    });
+    throw {
+      RE_EXN_ID: Height_invariant_broken,
+      Error: new Error()
+    };
   }
   let diff = Pervasives.abs(hl - hr | 0);
   if (diff > 2) {
-    throw new Error(Height_diff_borken, {
-      cause: {
-        RE_EXN_ID: Height_diff_borken
-      }
-    });
+    throw {
+      RE_EXN_ID: Height_diff_borken,
+      Error: new Error()
+    };
   }
   return h;
 }
@@ -250,16 +246,15 @@ function internal_bal(l, v, r) {
   hr = typeof r !== "object" ? 0 : r._3;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "set_gen.res",
-            278,
-            15
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "set_gen.res",
+          278,
+          15
+        ],
+        Error: new Error()
+      };
     }
     let lr = l._2;
     let lv = l._1;
@@ -270,16 +265,15 @@ function internal_bal(l, v, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, lr._0), lr._1, create(lr._2, v, r));
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "set_gen.res",
-          288,
-          19
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "set_gen.res",
+        288,
+        19
+      ],
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -291,16 +285,15 @@ function internal_bal(l, v, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "set_gen.res",
-          300,
-          15
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "set_gen.res",
+        300,
+        15
+      ],
+      Error: new Error()
+    };
   }
   let rr = r._2;
   let rv = r._1;
@@ -311,26 +304,24 @@ function internal_bal(l, v, r) {
   if (typeof rl === "object") {
     return create(create(l, v, rl._0), rl._1, create(rl._2, rv, rr));
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "set_gen.res",
-        306,
-        19
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "set_gen.res",
+      306,
+      19
+    ],
+    Error: new Error()
+  };
 }
 
 function remove_min_elt(x) {
   if (typeof x !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = x._0;
   if (typeof l !== "object") {
@@ -538,16 +529,15 @@ function of_sorted_list(l) {
         match$4[1]
       ];
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "set_gen.res",
-          447,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "set_gen.res",
+        447,
+        18
+      ],
+      Error: new Error()
+    };
   };
   return sub(List.length(l), l)[0];
 }
diff --git a/jscomp/test/sexp.js b/jscomp/test/sexp.js
index 3ad3c16eae..92adfe4154 100644
--- a/jscomp/test/sexp.js
+++ b/jscomp/test/sexp.js
@@ -477,12 +477,11 @@ function get_exn(e) {
   if (e !== undefined) {
     return Caml_option.valFromOption(e);
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "CCSexp.Traverse.get_exn"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "CCSexp.Traverse.get_exn",
+    Error: new Error()
+  };
 }
 
 let of_unit = {
diff --git a/jscomp/test/sexpm.js b/jscomp/test/sexpm.js
index ee81d710c7..23f147a379 100644
--- a/jscomp/test/sexpm.js
+++ b/jscomp/test/sexpm.js
@@ -22,18 +22,16 @@ function _must_escape(s) {
           if (c !== 92) {
             exit = 1;
           } else {
-            throw new Error(Pervasives.Exit, {
-              cause: {
-                RE_EXN_ID: Pervasives.Exit
-              }
-            });
+            throw {
+              RE_EXN_ID: Pervasives.Exit,
+              Error: new Error()
+            };
           }
         } else {
-          throw new Error(Pervasives.Exit, {
-            cause: {
-              RE_EXN_ID: Pervasives.Exit
-            }
-          });
+          throw {
+            RE_EXN_ID: Pervasives.Exit,
+            Error: new Error()
+          };
         }
       } else if (c >= 11) {
         if (c >= 32) {
@@ -50,31 +48,28 @@ function _must_escape(s) {
             case 34 :
             case 40 :
             case 41 :
-              throw new Error(Pervasives.Exit, {
-                cause: {
-                  RE_EXN_ID: Pervasives.Exit
-                }
-              });
+              throw {
+                RE_EXN_ID: Pervasives.Exit,
+                Error: new Error()
+              };
           }
         } else {
           exit = 1;
         }
       } else {
         if (c >= 9) {
-          throw new Error(Pervasives.Exit, {
-            cause: {
-              RE_EXN_ID: Pervasives.Exit
-            }
-          });
+          throw {
+            RE_EXN_ID: Pervasives.Exit,
+            Error: new Error()
+          };
         }
         exit = 1;
       }
       if (exit === 1 && c > 127) {
-        throw new Error(Pervasives.Exit, {
-          cause: {
-            RE_EXN_ID: Pervasives.Exit
-          }
-        });
+        throw {
+          RE_EXN_ID: Pervasives.Exit,
+          Error: new Error()
+        };
       }
       
     }
@@ -84,9 +79,7 @@ function _must_escape(s) {
     if (exn.RE_EXN_ID === Pervasives.Exit) {
       return true;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -161,16 +154,15 @@ function _refill(t, k_succ, k_fail) {
 
 function _get(t) {
   if (t.i >= t.len) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "sexpm.res",
-          111,
-          4
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "sexpm.res",
+        111,
+        4
+      ],
+      Error: new Error()
+    };
   }
   let c = Caml_bytes.get(t.buf, t.i);
   t.i = t.i + 1 | 0;
@@ -232,16 +224,15 @@ function expr_starting_with(c, k, t) {
     if (c >= 32) {
       switch (c) {
         case 32 :
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "sexpm.res",
-                152,
-                27
-              ]
-            }
-          });
+          throw {
+            RE_EXN_ID: "Assert_failure",
+            _1: [
+              "sexpm.res",
+              152,
+              27
+            ],
+            Error: new Error()
+          };
         case 34 :
           return quoted(k, t);
         case 33 :
@@ -259,16 +250,15 @@ function expr_starting_with(c, k, t) {
     }
     
   } else if (c >= 9) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "sexpm.res",
-          152,
-          27
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "sexpm.res",
+        152,
+        27
+      ],
+      Error: new Error()
+    };
   }
   Buffer.add_char(t.atom, c);
   return atom(k, t);
diff --git a/jscomp/test/stack_comp_test.js b/jscomp/test/stack_comp_test.js
index e48789bbee..7a41fdc6ec 100644
--- a/jscomp/test/stack_comp_test.js
+++ b/jscomp/test/stack_comp_test.js
@@ -64,9 +64,7 @@ function does_raise(f, s) {
     if (exn.RE_EXN_ID === Stack.Empty) {
       return true;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/stream_parser_test.js b/jscomp/test/stream_parser_test.js
index 2c52c45039..21d927d1a4 100644
--- a/jscomp/test/stream_parser_test.js
+++ b/jscomp/test/stream_parser_test.js
@@ -40,37 +40,33 @@ function parse(token) {
             if (match._0 === ")") {
               return v;
             }
-            throw new Error(Parse_error, {
-              cause: {
-                RE_EXN_ID: Parse_error,
-                _1: "Unbalanced parens"
-              }
-            });
-          }
-          throw new Error(Parse_error, {
-            cause: {
+            throw {
               RE_EXN_ID: Parse_error,
-              _1: "Unbalanced parens"
-            }
-          });
+              _1: "Unbalanced parens",
+              Error: new Error()
+            };
+          }
+          throw {
+            RE_EXN_ID: Parse_error,
+            _1: "Unbalanced parens",
+            Error: new Error()
+          };
         }
         Queue.push(n, look_ahead);
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error,
-            _1: "unexpected token"
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          _1: "unexpected token",
+          Error: new Error()
+        };
       case "Int" :
         return n._0;
       default:
         Queue.push(n, look_ahead);
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error,
-            _1: "unexpected token"
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          _1: "unexpected token",
+          Error: new Error()
+        };
     }
   };
   let parse_term = () => parse_term_aux(parse_atom());
@@ -173,35 +169,31 @@ function l_parse(token) {
             if (t._0 === ")") {
               return v;
             }
-            throw new Error(Parse_error, {
-              cause: {
-                RE_EXN_ID: Parse_error,
-                _1: "Unbalanced )"
-              }
-            });
-          }
-          throw new Error(Parse_error, {
-            cause: {
+            throw {
               RE_EXN_ID: Parse_error,
-              _1: "Unbalanced )"
-            }
-          });
-        }
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error,
-            _1: "Unexpected token"
+              _1: "Unbalanced )",
+              Error: new Error()
+            };
           }
-        });
+          throw {
+            RE_EXN_ID: Parse_error,
+            _1: "Unbalanced )",
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: Parse_error,
+          _1: "Unexpected token",
+          Error: new Error()
+        };
       case "Int" :
         return i._0;
       default:
-        throw new Error(Parse_error, {
-          cause: {
-            RE_EXN_ID: Parse_error,
-            _1: "Unexpected token"
-          }
-        });
+        throw {
+          RE_EXN_ID: Parse_error,
+          _1: "Unexpected token",
+          Error: new Error()
+        };
     }
   };
   let parse_f_aux = _a => {
diff --git a/jscomp/test/string_set.js b/jscomp/test/string_set.js
index 75578cd7f2..13db6739ce 100644
--- a/jscomp/test/string_set.js
+++ b/jscomp/test/string_set.js
@@ -223,11 +223,10 @@ function find(x, _tree) {
   while (true) {
     let tree = _tree;
     if (typeof tree !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = tree._1;
     let c = Caml.string_compare(x, v);
diff --git a/jscomp/test/string_test.js b/jscomp/test/string_test.js
index ecfd814856..5922bf6be3 100644
--- a/jscomp/test/string_test.js
+++ b/jscomp/test/string_test.js
@@ -72,9 +72,7 @@ function rev_split_by_char(c, s) {
           tl: l
         };
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   return loop(0, /* [] */0);
@@ -102,9 +100,7 @@ function xsplit(delim, s) {
             tl: l
           };
         }
-        throw new Error(exn.RE_EXN_ID, {
-          cause: exn
-        });
+        throw exn;
       }
       let l_0 = $$String.sub(s, i$p + 1 | 0, (x - i$p | 0) - 1 | 0);
       let l$1 = {
diff --git a/jscomp/test/stringmatch_test.js b/jscomp/test/stringmatch_test.js
index e9632da06a..f517fd954e 100644
--- a/jscomp/test/stringmatch_test.js
+++ b/jscomp/test/stringmatch_test.js
@@ -11,42 +11,39 @@ function tst01(s) {
 }
 
 if (tst01("") !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        22,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      22,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst01("\x00\x00\x00\x03") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        23,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      23,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst01("\x00\x00\x00\x00\x00\x00\x00\x07") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        24,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      24,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function tst02(s) {
@@ -55,28 +52,26 @@ function tst02(s) {
     if (len >= 0) {
       return 1;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "stringmatch_test.res",
-          33,
-          21
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "stringmatch_test.res",
+        33,
+        21
+      ],
+      Error: new Error()
+    };
   }
   if (len === 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "stringmatch_test.res",
-          35,
-          21
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "stringmatch_test.res",
+        35,
+        21
+      ],
+      Error: new Error()
+    };
   }
   if (s === "A") {
     return 2;
@@ -86,68 +81,63 @@ function tst02(s) {
 }
 
 if (tst02("") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        42,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      42,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst02("A") !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        43,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      43,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst02("B") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        44,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      44,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst02("\x00\x00\x00\x00\x00\x00\x00\x07") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        45,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      45,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst02("\x00\x00\x00\x03") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        46,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      46,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function tst03(s) {
@@ -206,627 +196,579 @@ function tst03(s) {
 }
 
 if (tst03("get_const") !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        131,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      131,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("set_congt") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        132,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      132,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("get_var") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        133,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      133,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("gat_ver") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        134,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      134,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("get_env") !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        135,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      135,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("get_env") !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        136,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      136,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("get_meth") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        137,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      137,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("met_geth") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        138,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      138,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("set_var") !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        139,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      139,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("sev_tar") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        140,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      140,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const") !== 5) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        141,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      141,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("ppa_const") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        142,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      142,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_var") !== 6) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        143,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      143,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_var") !== 6) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        144,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      144,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_env") !== 7) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        145,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      145,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("epp_anv") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        146,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      146,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_meth") !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        147,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      147,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("atp_meph") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        148,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      148,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const_const") !== 9) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        149,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      149,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const_const") !== 9) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        150,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      150,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const_var") !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        151,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      151,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("atp_consp_var") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        152,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      152,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const_env") !== 11) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        153,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      153,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_constne_v") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        154,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      154,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_const_meth") !== 12) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        155,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      155,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("spp_conat_meth") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        156,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      156,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_var_const") !== 13) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        157,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      157,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_va_rconst") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        158,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      158,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_env_const") !== 14) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        159,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      159,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_env_const") !== 14) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        160,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      160,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_meth_const") !== 15) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        161,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      161,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("app_teth_consm") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        162,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      162,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_app_const") !== 16) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        163,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      163,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("math_epp_const") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        164,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      164,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_app_var") !== 17) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        165,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      165,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_app_var") !== 17) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        166,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      166,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_app_env") !== 18) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        167,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      167,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("eeth_app_mnv") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        168,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      168,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_app_meth") !== 19) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        169,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      169,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("meth_apt_meph") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        170,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      170,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("send_const") !== 20) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        171,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      171,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("tend_conss") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        172,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      172,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("send_var") !== 21) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        173,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      173,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("serd_van") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        174,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      174,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("send_env") !== 22) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        175,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      175,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("sen_denv") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        176,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      176,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("send_meth") !== 23) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        177,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      177,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst03("tend_mesh") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        178,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      178,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function tst04(s) {
@@ -861,250 +803,231 @@ function tst04(s) {
 }
 
 if (tst04("AAAAAAAA") !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        215,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      215,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAAAAAAAAAAA") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        216,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      216,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAAAAAAAAAAAAAAAAAAA") !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        217,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      217,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        218,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      218,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("BBBBBBBB") !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        219,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      219,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("BBBBBBBBBBBBBBBB") !== 5) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        220,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      220,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("BBBBBBBBBBBBBBBBBBBBBBBB") !== 6) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        221,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      221,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB") !== 7) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        222,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      222,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("CCCCCCCC") !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        223,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      223,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("CCCCCCCCCCCCCCCC") !== 9) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        224,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      224,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("CCCCCCCCCCCCCCCCCCCCCCCC") !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        225,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      225,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC") !== 11) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        226,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      226,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        227,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      227,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("DDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        228,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      228,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("DDDDDDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        229,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      229,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAADDDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        230,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      230,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAADDDDDDDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        231,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      231,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAADDDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        232,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      232,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst04("AAAAAAAAAAAAAAADDDD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        233,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      233,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function tst05(s) {
@@ -1141,289 +1064,267 @@ function tst05(s) {
 }
 
 if (tst05("AAA") !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        272,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      272,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAA") !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        273,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      273,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAA") !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        274,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      274,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAA") !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        275,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      275,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAA") !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        276,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      276,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAAAAAAA") !== 5) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        277,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      277,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAAAAAAAAAAA") !== 6) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        278,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      278,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAAAAAAAAAAAAAAA") !== 7) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        279,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      279,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBB") !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        280,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      280,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBB") !== 9) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        281,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      281,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBBB") !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        282,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      282,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBBBB") !== 11) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        283,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      283,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBBBBB") !== 12) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        284,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      284,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        285,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      285,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        286,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      286,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        287,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      287,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        288,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      288,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("AAAAAAAD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        289,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      289,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        290,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      290,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        291,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      291,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBBBBD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        292,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      292,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst05("BBBBBBBD") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        293,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      293,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let s00 = "and";
@@ -1986,2408 +1887,2223 @@ function tst06(s) {
 }
 
 if (tst06(s00) !== 0) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        582,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      582,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t00) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        583,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      583,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s01) !== 1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        584,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      584,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t01) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        585,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      585,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s02) !== 2) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        586,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      586,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t02) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        587,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      587,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s03) !== 3) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        588,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      588,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t03) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        589,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      589,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s04) !== 4) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        590,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      590,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t04) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        591,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      591,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s05) !== 5) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        592,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      592,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t05) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        593,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      593,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s06) !== 6) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        594,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      594,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t06) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        595,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      595,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s07) !== 7) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        596,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      596,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t07) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        597,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      597,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s08) !== 8) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        598,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      598,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t08) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        599,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      599,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s09) !== 9) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        600,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      600,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t09) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        601,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      601,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s10) !== 10) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        602,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      602,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t10) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        603,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      603,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s11) !== 11) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        604,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      604,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t11) !== 11) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        605,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      605,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s12) !== 12) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        606,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      606,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t12) !== 12) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        607,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      607,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s13) !== 13) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        608,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      608,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t13) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        609,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      609,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s14) !== 14) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        610,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      610,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t14) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        611,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      611,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s15) !== 15) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        612,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      612,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t15) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        613,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      613,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s16) !== 16) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        614,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      614,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t16) !== 16) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        615,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      615,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s17) !== 17) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        616,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      616,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t17) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        617,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      617,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s18) !== 18) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        618,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      618,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t18) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        619,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      619,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s19) !== 19) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        620,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      620,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t19) !== 19) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        621,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      621,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s20) !== 20) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        622,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      622,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t20) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        623,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      623,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s21) !== 21) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        624,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      624,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t21) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        625,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      625,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s22) !== 22) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        626,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      626,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t22) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        627,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      627,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s23) !== 23) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        628,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      628,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t23) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        629,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      629,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s24) !== 24) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        630,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      630,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t24) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        631,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      631,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s25) !== 25) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        632,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      632,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t25) !== 25) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        633,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      633,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s26) !== 26) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        634,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      634,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t26) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        635,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      635,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s27) !== 27) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        636,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      636,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t27) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        637,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      637,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s28) !== 28) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        638,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      638,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t28) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        639,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      639,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s29) !== 29) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        640,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      640,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t29) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        641,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      641,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s30) !== 30) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        642,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      642,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t30) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        643,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      643,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s31) !== 31) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        644,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      644,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t31) !== 31) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        645,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      645,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s32) !== 32) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        646,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      646,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t32) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        647,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      647,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s33) !== 33) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        648,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      648,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t33) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        649,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      649,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s34) !== 34) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        650,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      650,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t34) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        651,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      651,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s35) !== 35) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        652,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      652,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t35) !== 35) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        653,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      653,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s36) !== 36) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        654,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      654,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t36) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        655,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      655,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s37) !== 37) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        656,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      656,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t37) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        657,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      657,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s38) !== 38) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        658,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      658,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t38) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        659,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      659,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s39) !== 39) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        660,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      660,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t39) !== 39) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        661,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      661,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s40) !== 40) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        662,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      662,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t40) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        663,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      663,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s41) !== 41) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        664,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      664,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t41) !== 41) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        665,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      665,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s42) !== 42) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        666,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      666,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t42) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        667,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      667,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s43) !== 43) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        668,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      668,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t43) !== 43) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        669,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      669,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s44) !== 44) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        670,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      670,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t44) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        671,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      671,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s45) !== 45) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        672,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      672,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t45) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        673,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      673,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s46) !== 46) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        674,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      674,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t46) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        675,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      675,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s47) !== 47) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        676,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      676,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t47) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        677,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      677,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s48) !== 48) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        678,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      678,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t48) !== 48) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        679,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      679,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s49) !== 49) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        680,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      680,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t49) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        681,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      681,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s50) !== 50) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        682,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      682,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t50) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        683,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      683,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s51) !== 51) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        684,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      684,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t51) !== 51) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        685,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      685,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s52) !== 52) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        686,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      686,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t52) !== 52) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        687,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      687,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s53) !== 53) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        688,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      688,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t53) !== 53) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        689,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      689,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s54) !== 54) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        690,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      690,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t54) !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        691,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      691,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s55) !== 55) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        692,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      692,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t55) !== 55) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        693,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      693,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s56) !== 56) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        694,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      694,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t56) !== 56) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        695,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      695,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s57) !== 57) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        696,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      696,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t57) !== 57) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        697,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      697,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s58) !== 58) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        698,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      698,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t58) !== 58) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        699,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      699,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s59) !== 59) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        700,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      700,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t59) !== 59) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        701,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      701,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s60) !== 60) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        702,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      702,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t60) !== 60) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        703,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      703,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s61) !== 61) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        704,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      704,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t61) !== 61) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        705,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      705,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s62) !== 62) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        706,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      706,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t62) !== 62) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        707,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      707,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s63) !== 63) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        708,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      708,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t63) !== 63) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        709,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      709,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s64) !== 64) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        710,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      710,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t64) !== 64) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        711,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      711,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s65) !== 65) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        712,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      712,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t65) !== 65) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        713,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      713,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s66) !== 66) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        714,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      714,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t66) !== 66) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        715,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      715,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s67) !== 67) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        716,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      716,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t67) !== 67) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        717,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      717,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s68) !== 68) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        718,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      718,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t68) !== 68) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        719,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      719,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s69) !== 69) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        720,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      720,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t69) !== 69) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        721,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      721,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s70) !== 70) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        722,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      722,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t70) !== 70) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        723,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      723,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s71) !== 71) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        724,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      724,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t71) !== 71) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        725,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      725,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s72) !== 72) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        726,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      726,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t72) !== 72) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        727,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      727,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s73) !== 73) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        728,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      728,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t73) !== 73) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        729,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      729,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s74) !== 74) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        730,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      730,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t74) !== 74) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        731,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      731,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s75) !== 75) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        732,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      732,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t75) !== 75) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        733,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      733,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s76) !== 76) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        734,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      734,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t76) !== 76) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        735,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      735,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s77) !== 77) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        736,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      736,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t77) !== 77) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        737,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      737,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s78) !== 78) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        738,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      738,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t78) !== 78) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        739,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      739,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s79) !== 79) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        740,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      740,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t79) !== 79) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        741,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      741,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s80) !== 80) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        742,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      742,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t80) !== 80) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        743,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      743,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s81) !== 81) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        744,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      744,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t81) !== 81) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        745,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      745,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s82) !== 82) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        746,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      746,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t82) !== 82) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        747,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      747,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s83) !== 83) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        748,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      748,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t83) !== 83) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        749,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      749,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s84) !== 84) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        750,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      750,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t84) !== 84) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        751,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      751,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s85) !== 85) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        752,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      752,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t85) !== 85) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        753,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      753,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s86) !== 86) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        754,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      754,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t86) !== 86) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        755,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      755,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s87) !== 87) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        756,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      756,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t87) !== 87) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        757,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      757,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s88) !== 88) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        758,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      758,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t88) !== 88) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        759,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      759,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s89) !== 89) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        760,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      760,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t89) !== 89) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        761,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      761,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s90) !== 90) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        762,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      762,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t90) !== 90) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        763,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      763,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(s91) !== 91) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        764,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      764,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06(t91) !== 91) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        765,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      765,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (tst06("") !== -1) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "stringmatch_test.res",
-        766,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "stringmatch_test.res",
+      766,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 exports.tst01 = tst01;
diff --git a/jscomp/test/test_array_primitive.js b/jscomp/test/test_array_primitive.js
index 3ac46e92e8..a840816333 100644
--- a/jscomp/test/test_array_primitive.js
+++ b/jscomp/test/test_array_primitive.js
@@ -13,24 +13,22 @@ function caml_array_sub(x, offset, len) {
 
 function caml_array_set(xs, index, newval) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   Caml_array.set(xs, index, newval);
 }
 
 function caml_array_get(xs, index) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return Caml_array.get(xs, index);
 }
diff --git a/jscomp/test/test_bool_equal.js b/jscomp/test/test_bool_equal.js
index d4a80430d8..549f7c36a7 100644
--- a/jscomp/test/test_bool_equal.js
+++ b/jscomp/test/test_bool_equal.js
@@ -18,52 +18,48 @@ function bool_equal(x, y) {
 
 function assertions() {
   if (!bool_equal(true, true)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "test_bool_equal.res",
-          16,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "test_bool_equal.res",
+        16,
+        2
+      ],
+      Error: new Error()
+    };
   }
   if (!bool_equal(false, false)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "test_bool_equal.res",
-          17,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "test_bool_equal.res",
+        17,
+        2
+      ],
+      Error: new Error()
+    };
   }
   if (bool_equal(true, false)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "test_bool_equal.res",
-          18,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "test_bool_equal.res",
+        18,
+        2
+      ],
+      Error: new Error()
+    };
   }
   if (bool_equal(false, true)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "test_bool_equal.res",
-          19,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "test_bool_equal.res",
+        19,
+        2
+      ],
+      Error: new Error()
+    };
   }
   
 }
diff --git a/jscomp/test/test_closure.js b/jscomp/test/test_closure.js
index 50cf48ad0a..2ab72395e4 100644
--- a/jscomp/test/test_closure.js
+++ b/jscomp/test/test_closure.js
@@ -23,16 +23,15 @@ let u = f();
 $$Array.iter(x => x(), u);
 
 if (v.contents !== 45) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "test_closure.res",
-        52,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "test_closure.res",
+      52,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 exports.v = v;
diff --git a/jscomp/test/test_exception.js b/jscomp/test/test_exception.js
index d8fd225654..c987a027fc 100644
--- a/jscomp/test/test_exception.js
+++ b/jscomp/test/test_exception.js
@@ -7,46 +7,41 @@ let Caml_exceptions = require("../../lib/js/caml_exceptions.js");
 let Local = /* @__PURE__ */Caml_exceptions.create("Test_exception.Local");
 
 function f() {
-  throw new Error(Local, {
-    cause: {
-      RE_EXN_ID: Local,
-      _1: 3
-    }
-  });
+  throw {
+    RE_EXN_ID: Local,
+    _1: 3,
+    Error: new Error()
+  };
 }
 
 function g() {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function h() {
-  throw new Error(Test_common.U, {
-    cause: {
-      RE_EXN_ID: Test_common.U,
-      _1: 3
-    }
-  });
+  throw {
+    RE_EXN_ID: Test_common.U,
+    _1: 3,
+    Error: new Error()
+  };
 }
 
 function x() {
-  throw new Error(Test_common.H, {
-    cause: {
-      RE_EXN_ID: Test_common.H
-    }
-  });
+  throw {
+    RE_EXN_ID: Test_common.H,
+    Error: new Error()
+  };
 }
 
 function xx() {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "x"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "x",
+    Error: new Error()
+  };
 }
 
 let Nullary = /* @__PURE__ */Caml_exceptions.create("Test_exception.Nullary");
diff --git a/jscomp/test/test_exception_escape.js b/jscomp/test/test_exception_escape.js
index 418fec2b66..b1fee39246 100644
--- a/jscomp/test/test_exception_escape.js
+++ b/jscomp/test/test_exception_escape.js
@@ -8,12 +8,11 @@ let A = /* @__PURE__ */Caml_exceptions.create("Test_exception_escape.N.A");
 let f;
 
 try {
-  throw new Error(A, {
-    cause: {
-      RE_EXN_ID: A,
-      _1: 3
-    }
-  });
+  throw {
+    RE_EXN_ID: A,
+    _1: 3,
+    Error: new Error()
+  };
 } catch (exn) {
   f = 3;
 }
diff --git a/jscomp/test/test_for_map.js b/jscomp/test/test_for_map.js
index d5400a46d9..58761a235a 100644
--- a/jscomp/test/test_for_map.js
+++ b/jscomp/test/test_for_map.js
@@ -43,12 +43,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -60,12 +59,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -78,12 +76,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -95,12 +92,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty(param) {
@@ -161,11 +157,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.int_compare(x, param.v);
     if (c === 0) {
@@ -180,11 +175,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -258,11 +252,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -366,11 +359,10 @@ function min_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -406,11 +398,10 @@ function max_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -444,12 +435,11 @@ function max_binding_opt(_param) {
 
 function remove_min_binding(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -753,16 +743,15 @@ function merge$1(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "map.res",
-          552,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "map.res",
+        552,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2.v;
   let match$1 = split(v2, s1);
diff --git a/jscomp/test/test_incomplete.js b/jscomp/test/test_incomplete.js
index bfcf01440e..22740d944e 100644
--- a/jscomp/test/test_incomplete.js
+++ b/jscomp/test/test_incomplete.js
@@ -6,16 +6,15 @@ function f(x) {
   if (!(x > 3 || x < 1)) {
     return /* 'a' */97;
   }
-  throw new Error("Match_failure", {
-    cause: {
-      RE_EXN_ID: "Match_failure",
-      _1: [
-        "test_incomplete.res",
-        3,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Match_failure",
+    _1: [
+      "test_incomplete.res",
+      3,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function f2(x) {
diff --git a/jscomp/test/test_int_map_find.js b/jscomp/test/test_int_map_find.js
index 8accca8abe..98227ccb29 100644
--- a/jscomp/test/test_int_map_find.js
+++ b/jscomp/test/test_int_map_find.js
@@ -32,12 +32,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -49,12 +48,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -67,12 +65,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -84,12 +81,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, param) {
diff --git a/jscomp/test/test_list.js b/jscomp/test/test_list.js
index c40fc0b557..fb1b9ac5d4 100644
--- a/jscomp/test/test_list.js
+++ b/jscomp/test/test_list.js
@@ -26,34 +26,31 @@ function hd(x) {
   if (x) {
     return x.hd;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "hd"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "hd",
+    Error: new Error()
+  };
 }
 
 function tl(x) {
   if (x) {
     return x.tl;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "tl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "tl",
+    Error: new Error()
+  };
 }
 
 function nth(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -68,12 +65,11 @@ function nth(l, n) {
       _l = l$1.tl;
       continue;
     }
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "nth",
+      Error: new Error()
+    };
   };
 }
 
@@ -207,22 +203,20 @@ function map2(f, l1, l2) {
         tl: map2(f, l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2",
+    Error: new Error()
+  };
 }
 
 function rev_map2(f, l1, l2) {
@@ -243,20 +237,18 @@ function rev_map2(f, l1, l2) {
         };
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     if (l2$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -273,22 +265,20 @@ function iter2(f, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.iter2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.iter2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.iter2",
+      Error: new Error()
+    };
   };
 }
 
@@ -304,20 +294,18 @@ function fold_left2(f, _accu, _l1, _l2) {
         _accu = f(accu, l1.hd, l2.hd);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     if (l2) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -328,20 +316,18 @@ function fold_right2(f, l1, l2, accu) {
     if (l2) {
       return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -387,22 +373,20 @@ function for_all2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.for_all2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.for_all2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return true;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.for_all2",
+      Error: new Error()
+    };
   };
 }
 
@@ -419,22 +403,20 @@ function exists2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.exists2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.exists2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return false;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.exists2",
+      Error: new Error()
+    };
   };
 }
 
@@ -477,11 +459,10 @@ function assoc(x, _x_) {
       _x_ = x_.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -496,11 +477,10 @@ function assq(x, _x_) {
       _x_ = x_.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -575,11 +555,10 @@ function find(p, _x) {
       _x = x.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -674,22 +653,20 @@ function combine(l1, l2) {
         tl: combine(l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.combine"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.combine",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.combine",
+    Error: new Error()
+  };
 }
 
 function merge(cmp, l1, l2) {
@@ -726,16 +703,15 @@ function chop(_k, _l) {
       _k = k - 1 | 0;
       continue;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "test_list.res",
-          343,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "test_list.res",
+        343,
+        11
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/jscomp/test/test_match_exception.js b/jscomp/test/test_match_exception.js
index 6fe415efa7..ee79886634 100644
--- a/jscomp/test/test_match_exception.js
+++ b/jscomp/test/test_match_exception.js
@@ -11,9 +11,7 @@ function f(g, x) {
     if (exn.RE_EXN_ID === "Not_found") {
       return 3;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/jscomp/test/test_per.js b/jscomp/test/test_per.js
index eea5830322..2932670776 100644
--- a/jscomp/test/test_per.js
+++ b/jscomp/test/test_per.js
@@ -7,21 +7,19 @@ let Caml_int64 = require("../../lib/js/caml_int64.js");
 let Caml_exceptions = require("../../lib/js/caml_exceptions.js");
 
 function failwith(s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function invalid_arg(s) {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 let Exit = /* @__PURE__ */Caml_exceptions.create("Test_per.Exit");
@@ -97,12 +95,11 @@ function $caret(s1, s2) {
 
 function char_of_int(n) {
   if (n < 0 || n > 255) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "char_of_int"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "char_of_int",
+      Error: new Error()
+    };
   }
   return n;
 }
diff --git a/jscomp/test/test_seq.js b/jscomp/test/test_seq.js
index 10c3093667..f3358b1402 100644
--- a/jscomp/test/test_seq.js
+++ b/jscomp/test/test_seq.js
@@ -23,24 +23,22 @@ function assoc3(x, _l) {
       _l = l.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
 function help_action() {
-  throw new Error(Stop, {
-    cause: {
-      RE_EXN_ID: Stop,
-      _1: {
-        TAG: "Unknown",
-        _0: "-help"
-      }
-    }
-  });
+  throw {
+    RE_EXN_ID: Stop,
+    _1: {
+      TAG: "Unknown",
+      _0: "-help"
+    },
+    Error: new Error()
+  };
 }
 
 function v(speclist) {
@@ -72,9 +70,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
   let add2;
@@ -96,9 +92,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn$1.RE_EXN_ID, {
-        cause: exn$1
-      });
+      throw exn$1;
     }
   }
   return Pervasives.$at(speclist, Pervasives.$at(add1, add2));
diff --git a/jscomp/test/test_set.js b/jscomp/test/test_set.js
index ff3dca7cfa..aea136d5da 100644
--- a/jscomp/test/test_set.js
+++ b/jscomp/test/test_set.js
@@ -31,12 +31,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r._3;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let lr = l._2;
       let lv = l._1;
@@ -47,12 +46,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, lr._0), lr._1, create(lr._2, v, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -64,12 +62,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let rr = r._2;
     let rv = r._1;
@@ -80,12 +77,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, v, rl._0), rl._1, create(rl._2, rv, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   };
   let add = (x, x_) => {
     if (typeof x_ !== "object") {
@@ -151,11 +147,10 @@ function Make(Ord) {
     while (true) {
       let x = _x;
       if (typeof x !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = x._0;
       if (typeof l !== "object") {
@@ -169,11 +164,10 @@ function Make(Ord) {
     while (true) {
       let x = _x;
       if (typeof x !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = x._2;
       if (typeof r !== "object") {
@@ -185,12 +179,11 @@ function Make(Ord) {
   };
   let remove_min_elt = x => {
     if (typeof x !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = x._0;
     if (typeof l !== "object") {
@@ -564,11 +557,10 @@ function Make(Ord) {
     while (true) {
       let x_ = _x_;
       if (typeof x_ !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = x_._1;
       let c = Ord.compare(x, v);
@@ -670,16 +662,15 @@ function Make(Ord) {
           match$4[1]
         ];
       }
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "test_set.res",
-            497,
-            20
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "test_set.res",
+          497,
+          20
+        ],
+        Error: new Error()
+      };
     };
     return sub(List.length(l), l)[0];
   };
diff --git a/jscomp/test/test_static_catch_ident.js b/jscomp/test/test_static_catch_ident.js
index 0f07ea108a..71f35bcd64 100644
--- a/jscomp/test/test_static_catch_ident.js
+++ b/jscomp/test/test_static_catch_ident.js
@@ -10,9 +10,7 @@ function scanf_bad_input(ib, x) {
   if (x.RE_EXN_ID === Scan_failure || x.RE_EXN_ID === "Failure") {
     s = x._1;
   } else {
-    throw new Error(x.RE_EXN_ID, {
-      cause: x
-    });
+    throw x;
   }
   for (let i = 0; i <= 100; ++i) {
     console.log(s);
diff --git a/jscomp/test/test_string.js b/jscomp/test/test_string.js
index 6cda6ae83e..22ba5db87b 100644
--- a/jscomp/test/test_string.js
+++ b/jscomp/test/test_string.js
@@ -11,16 +11,15 @@ function f(x) {
     case "bbbb" :
       return 1;
     default:
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "test_string.res",
-            5,
-            17
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "test_string.res",
+          5,
+          17
+        ],
+        Error: new Error()
+      };
   }
 }
 
diff --git a/jscomp/test/test_string_case.js b/jscomp/test/test_string_case.js
index 867814c4a6..dcd3cb6352 100644
--- a/jscomp/test/test_string_case.js
+++ b/jscomp/test/test_string_case.js
@@ -9,16 +9,15 @@ function f(x) {
     case "bcde" :
       return 1;
     default:
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "test_string_case.res",
-            5,
-            9
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "test_string_case.res",
+          5,
+          9
+        ],
+        Error: new Error()
+      };
   }
 }
 
diff --git a/jscomp/test/test_string_const.js b/jscomp/test/test_string_const.js
index cadb0599f9..67c811f372 100644
--- a/jscomp/test/test_string_const.js
+++ b/jscomp/test/test_string_const.js
@@ -16,9 +16,7 @@ try {
     console.log(e._1);
     hh = /* 'a' */97;
   } else {
-    throw new Error(e.RE_EXN_ID, {
-      cause: e
-    });
+    throw e;
   }
 }
 
diff --git a/jscomp/test/test_string_map.js b/jscomp/test/test_string_map.js
index 21d8f1df73..fa07819203 100644
--- a/jscomp/test/test_string_map.js
+++ b/jscomp/test/test_string_map.js
@@ -31,12 +31,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -48,12 +47,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -66,12 +64,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -83,12 +80,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, data, param) {
@@ -141,11 +137,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml.string_compare(x, param.v);
     if (c === 0) {
diff --git a/jscomp/test/test_trywith.js b/jscomp/test/test_trywith.js
index f327c553a7..bd5cd7321f 100644
--- a/jscomp/test/test_trywith.js
+++ b/jscomp/test/test_trywith.js
@@ -18,9 +18,7 @@ function ff(g, x) {
   } catch (raw_exn) {
     let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
     if (exn.RE_EXN_ID !== "Not_found") {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     
   }
@@ -29,9 +27,7 @@ function ff(g, x) {
   } catch (raw_exn$1) {
     let exn$1 = Caml_js_exceptions.internalToOCamlException(raw_exn$1);
     if (exn$1.RE_EXN_ID !== Out_of_memory) {
-      throw new Error(exn$1.RE_EXN_ID, {
-        cause: exn$1
-      });
+      throw exn$1;
     }
     
   }
@@ -40,9 +36,7 @@ function ff(g, x) {
   } catch (raw_exn$2) {
     let exn$2 = Caml_js_exceptions.internalToOCamlException(raw_exn$2);
     if (exn$2.RE_EXN_ID !== Sys_error) {
-      throw new Error(exn$2.RE_EXN_ID, {
-        cause: exn$2
-      });
+      throw exn$2;
     }
     
   }
@@ -51,9 +45,7 @@ function ff(g, x) {
   } catch (raw_exn$3) {
     let exn$3 = Caml_js_exceptions.internalToOCamlException(raw_exn$3);
     if (exn$3.RE_EXN_ID !== "Invalid_argument") {
-      throw new Error(exn$3.RE_EXN_ID, {
-        cause: exn$3
-      });
+      throw exn$3;
     }
     
   }
@@ -62,9 +54,7 @@ function ff(g, x) {
   } catch (raw_exn$4) {
     let exn$4 = Caml_js_exceptions.internalToOCamlException(raw_exn$4);
     if (exn$4.RE_EXN_ID !== "End_of_file") {
-      throw new Error(exn$4.RE_EXN_ID, {
-        cause: exn$4
-      });
+      throw exn$4;
     }
     
   }
@@ -73,9 +63,7 @@ function ff(g, x) {
   } catch (raw_exn$5) {
     let exn$5 = Caml_js_exceptions.internalToOCamlException(raw_exn$5);
     if (exn$5.RE_EXN_ID !== "Match_failure") {
-      throw new Error(exn$5.RE_EXN_ID, {
-        cause: exn$5
-      });
+      throw exn$5;
     }
     
   }
@@ -84,9 +72,7 @@ function ff(g, x) {
   } catch (raw_exn$6) {
     let exn$6 = Caml_js_exceptions.internalToOCamlException(raw_exn$6);
     if (exn$6.RE_EXN_ID !== Stack_overflow) {
-      throw new Error(exn$6.RE_EXN_ID, {
-        cause: exn$6
-      });
+      throw exn$6;
     }
     
   }
@@ -95,9 +81,7 @@ function ff(g, x) {
   } catch (raw_exn$7) {
     let exn$7 = Caml_js_exceptions.internalToOCamlException(raw_exn$7);
     if (exn$7.RE_EXN_ID !== Sys_blocked_io) {
-      throw new Error(exn$7.RE_EXN_ID, {
-        cause: exn$7
-      });
+      throw exn$7;
     }
     
   }
@@ -106,9 +90,7 @@ function ff(g, x) {
   } catch (raw_exn$8) {
     let exn$8 = Caml_js_exceptions.internalToOCamlException(raw_exn$8);
     if (exn$8.RE_EXN_ID !== "Assert_failure") {
-      throw new Error(exn$8.RE_EXN_ID, {
-        cause: exn$8
-      });
+      throw exn$8;
     }
     
   }
@@ -119,18 +101,15 @@ function ff(g, x) {
     if (exn$9.RE_EXN_ID === "Undefined_recursive_module") {
       return;
     }
-    throw new Error(exn$9.RE_EXN_ID, {
-      cause: exn$9
-    });
+    throw exn$9;
   }
 }
 
 function u() {
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function f(x) {
@@ -140,16 +119,15 @@ function f(x) {
   if (x.TAG === "D") {
     return 1;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "test_trywith.res",
-        59,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "test_trywith.res",
+      59,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 let u1 = "bad character decimal encoding \\";
diff --git a/jscomp/test/test_while_closure.js b/jscomp/test/test_while_closure.js
index 7235c903b0..c225a30bbb 100644
--- a/jscomp/test/test_while_closure.js
+++ b/jscomp/test/test_while_closure.js
@@ -28,16 +28,15 @@ $$Array.iter(x => x(), arr);
 console.log(String(v.contents));
 
 if (v.contents !== 45) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "test_while_closure.res",
-        55,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "test_while_closure.res",
+      55,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let count = 10;
diff --git a/jscomp/test/ticker.js b/jscomp/test/ticker.js
index 8f8c2e3a23..35dd8d70b9 100644
--- a/jscomp/test/ticker.js
+++ b/jscomp/test/ticker.js
@@ -32,9 +32,7 @@ function split(delim, s) {
             tl: l
           };
         }
-        throw new Error(exn.RE_EXN_ID, {
-          cause: exn
-        });
+        throw exn;
       }
       let l_0 = $$String.sub(s, i$p + 1 | 0, (x - i$p | 0) - 1 | 0);
       let l$1 = {
@@ -132,12 +130,11 @@ function bal(l, x, d, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let ld = l.d;
@@ -149,12 +146,11 @@ function bal(l, x, d, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -167,12 +163,11 @@ function bal(l, x, d, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rd = r.d;
@@ -184,12 +179,11 @@ function bal(l, x, d, r) {
   if (typeof rl === "object") {
     return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Map.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Map.bal",
+    Error: new Error()
+  };
 }
 
 function is_empty(param) {
@@ -250,11 +244,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let c = Caml_obj.compare(x, param.v);
     if (c === 0) {
@@ -269,11 +262,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -347,11 +339,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -455,11 +446,10 @@ function min_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -495,11 +485,10 @@ function max_binding(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -533,12 +522,11 @@ function max_binding_opt(_param) {
 
 function remove_min_binding(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -842,16 +830,15 @@ function merge$1(f, s1, s2) {
     
   }
   if (typeof s2 !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "map.res",
-          552,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "map.res",
+        552,
+        11
+      ],
+      Error: new Error()
+    };
   }
   let v2 = s2.v;
   let match$1 = split$1(v2, s1);
@@ -1159,38 +1146,34 @@ function compute_update_sequences(all_tickers) {
       let x = lhs.rank;
       if (typeof x !== "object") {
         if (x === "Uninitialized") {
-          throw new Error("Failure", {
-            cause: {
-              RE_EXN_ID: "Failure",
-              _1: "All nodes should be ranked"
-            }
-          });
-        }
-        throw new Error("Failure", {
-          cause: {
+          throw {
             RE_EXN_ID: "Failure",
-            _1: "All nodes should be ranked"
-          }
-        });
+            _1: "All nodes should be ranked",
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "All nodes should be ranked",
+          Error: new Error()
+        };
       } else {
         let y = rhs.rank;
         if (typeof y === "object") {
           return Caml.int_compare(x._0, y._0);
         }
         if (y === "Uninitialized") {
-          throw new Error("Failure", {
-            cause: {
-              RE_EXN_ID: "Failure",
-              _1: "All nodes should be ranked"
-            }
-          });
-        }
-        throw new Error("Failure", {
-          cause: {
+          throw {
             RE_EXN_ID: "Failure",
-            _1: "All nodes should be ranked"
-          }
-        });
+            _1: "All nodes should be ranked",
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "All nodes should be ranked",
+          Error: new Error()
+        };
       }
     }, l);
     return add(k, l$1, map);
@@ -1206,12 +1189,11 @@ function process_quote(ticker_map, new_ticker, new_value) {
         ticker.value = new_value;
         return;
       }
-      throw new Error("Failure", {
-        cause: {
-          RE_EXN_ID: "Failure",
-          _1: "Only single Market ticker should be udpated upon a new quote"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Failure",
+        _1: "Only single Market ticker should be udpated upon a new quote",
+        Error: new Error()
+      };
     }
     let match$1 = match._0;
     let match$2 = match$1.lhs.value;
@@ -1250,12 +1232,11 @@ function process_input_line(ticker_map, all_tickers, line) {
           let match$1 = match.tl;
           if (match$1) {
             if (match$1.tl) {
-              throw new Error("Failure", {
-                cause: {
-                  RE_EXN_ID: "Failure",
-                  _1: "Invalid input line"
-                }
-              });
+              throw {
+                RE_EXN_ID: "Failure",
+                _1: "Invalid input line",
+                Error: new Error()
+              };
             }
             let ticker_map$1 = ticker_map !== undefined ? Caml_option.valFromOption(ticker_map) : compute_update_sequences(all_tickers);
             let value = Caml_format.float_of_string(match$1.hd);
@@ -1265,19 +1246,17 @@ function process_input_line(ticker_map, all_tickers, line) {
               Caml_option.some(ticker_map$1)
             ];
           }
-          throw new Error("Failure", {
-            cause: {
-              RE_EXN_ID: "Failure",
-              _1: "Invalid input line"
-            }
-          });
-        }
-        throw new Error("Failure", {
-          cause: {
+          throw {
             RE_EXN_ID: "Failure",
-            _1: "Invalid input line"
-          }
-        });
+            _1: "Invalid input line",
+            Error: new Error()
+          };
+        }
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "Invalid input line",
+          Error: new Error()
+        };
       case "R" :
         let match$2 = tokens.tl;
         if (match$2) {
@@ -1291,12 +1270,11 @@ function process_input_line(ticker_map, all_tickers, line) {
                   let match$5 = match$4.tl;
                   if (match$5) {
                     if (match$5.tl) {
-                      throw new Error("Failure", {
-                        cause: {
-                          RE_EXN_ID: "Failure",
-                          _1: "Invalid input line"
-                        }
-                      });
+                      throw {
+                        RE_EXN_ID: "Failure",
+                        _1: "Invalid input line",
+                        Error: new Error()
+                      };
                     }
                     return [
                       {
@@ -1306,31 +1284,28 @@ function process_input_line(ticker_map, all_tickers, line) {
                       ticker_map
                     ];
                   }
-                  throw new Error("Failure", {
-                    cause: {
-                      RE_EXN_ID: "Failure",
-                      _1: "Invalid input line"
-                    }
-                  });
-                }
-                throw new Error("Failure", {
-                  cause: {
+                  throw {
                     RE_EXN_ID: "Failure",
-                    _1: "Invalid input line"
-                  }
-                });
+                    _1: "Invalid input line",
+                    Error: new Error()
+                  };
+                }
+                throw {
+                  RE_EXN_ID: "Failure",
+                  _1: "Invalid input line",
+                  Error: new Error()
+                };
               case "-" :
                 let match$6 = match$3.tl;
                 if (match$6) {
                   let match$7 = match$6.tl;
                   if (match$7) {
                     if (match$7.tl) {
-                      throw new Error("Failure", {
-                        cause: {
-                          RE_EXN_ID: "Failure",
-                          _1: "Invalid input line"
-                        }
-                      });
+                      throw {
+                        RE_EXN_ID: "Failure",
+                        _1: "Invalid input line",
+                        Error: new Error()
+                      };
                     }
                     return [
                       {
@@ -1340,27 +1315,24 @@ function process_input_line(ticker_map, all_tickers, line) {
                       ticker_map
                     ];
                   }
-                  throw new Error("Failure", {
-                    cause: {
-                      RE_EXN_ID: "Failure",
-                      _1: "Invalid input line"
-                    }
-                  });
-                }
-                throw new Error("Failure", {
-                  cause: {
+                  throw {
                     RE_EXN_ID: "Failure",
-                    _1: "Invalid input line"
-                  }
-                });
+                    _1: "Invalid input line",
+                    Error: new Error()
+                  };
+                }
+                throw {
+                  RE_EXN_ID: "Failure",
+                  _1: "Invalid input line",
+                  Error: new Error()
+                };
               case "S" :
                 if (match$3.tl) {
-                  throw new Error("Failure", {
-                    cause: {
-                      RE_EXN_ID: "Failure",
-                      _1: "Invalid input line"
-                    }
-                  });
+                  throw {
+                    RE_EXN_ID: "Failure",
+                    _1: "Invalid input line",
+                    Error: new Error()
+                  };
                 }
                 return [
                   {
@@ -1375,44 +1347,39 @@ function process_input_line(ticker_map, all_tickers, line) {
                   ticker_map
                 ];
               default:
-                throw new Error("Failure", {
-                  cause: {
-                    RE_EXN_ID: "Failure",
-                    _1: "Invalid input line"
-                  }
-                });
+                throw {
+                  RE_EXN_ID: "Failure",
+                  _1: "Invalid input line",
+                  Error: new Error()
+                };
             }
           } else {
-            throw new Error("Failure", {
-              cause: {
-                RE_EXN_ID: "Failure",
-                _1: "Invalid input line"
-              }
-            });
+            throw {
+              RE_EXN_ID: "Failure",
+              _1: "Invalid input line",
+              Error: new Error()
+            };
           }
         } else {
-          throw new Error("Failure", {
-            cause: {
-              RE_EXN_ID: "Failure",
-              _1: "Invalid input line"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Failure",
+            _1: "Invalid input line",
+            Error: new Error()
+          };
         }
       default:
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "Invalid input line"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "Invalid input line",
+          Error: new Error()
+        };
     }
   } else {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "Invalid input line"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "Invalid input line",
+      Error: new Error()
+    };
   }
 }
 
diff --git a/jscomp/test/topsort_test.js b/jscomp/test/topsort_test.js
index 286b48e805..9288827d8b 100644
--- a/jscomp/test/topsort_test.js
+++ b/jscomp/test/topsort_test.js
@@ -121,16 +121,15 @@ if (!Caml_obj.equal(dfs1({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        35,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      35,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 console.log("");
@@ -160,16 +159,15 @@ if (!Caml_obj.equal(dfs1({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        38,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      38,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function dfs2(nodes, graph, visited) {
@@ -222,16 +220,15 @@ if (!Caml_obj.equal(dfs2({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        57,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      57,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(dfs2({
@@ -259,16 +256,15 @@ if (!Caml_obj.equal(dfs2({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        58,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      58,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 function dfs3(nodes, graph) {
@@ -314,16 +310,15 @@ if (!Caml_obj.equal(dfs3({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        74,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      74,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 if (!Caml_obj.equal(dfs3({
@@ -351,16 +346,15 @@ if (!Caml_obj.equal(dfs3({
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        75,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      75,
+      2
+    ],
+    Error: new Error()
+  };
 }
 
 let grwork = {
@@ -439,16 +433,15 @@ if (!Caml_obj.equal(unsafe_topsort(grwork), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        112,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      112,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function height(param) {
@@ -480,12 +473,11 @@ function bal(l, v, r) {
   hr = typeof r !== "object" ? 0 : r.h;
   if (hl > (hr + 2 | 0)) {
     if (typeof l !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let lr = l.r;
     let lv = l.v;
@@ -496,12 +488,11 @@ function bal(l, v, r) {
     if (typeof lr === "object") {
       return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   if (hr <= (hl + 2 | 0)) {
     return {
@@ -513,12 +504,11 @@ function bal(l, v, r) {
     };
   }
   if (typeof r !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   }
   let rr = r.r;
   let rv = r.v;
@@ -529,12 +519,11 @@ function bal(l, v, r) {
   if (typeof rl === "object") {
     return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Set.bal"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Set.bal",
+    Error: new Error()
+  };
 }
 
 function add(x, param) {
@@ -618,11 +607,10 @@ function min_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -652,11 +640,10 @@ function max_elt(_param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let r = param.r;
     if (typeof r !== "object") {
@@ -684,12 +671,11 @@ function max_elt_opt(_param) {
 
 function remove_min_elt(param) {
   if (typeof param !== "object") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.remove_min_elt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.remove_min_elt",
+      Error: new Error()
+    };
   }
   let l = param.l;
   if (typeof l !== "object") {
@@ -1103,11 +1089,10 @@ function find(x, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     let c = Caml.string_compare(x, v);
@@ -1123,11 +1108,10 @@ function find_first(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -1189,11 +1173,10 @@ function find_last(f, _param) {
   while (true) {
     let param = _param;
     if (typeof param !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let v = param.v;
     if (f(v)) {
@@ -1400,16 +1383,15 @@ function of_list(l) {
             match$4[1]
           ];
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "set.res",
-              691,
-              20
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "set.res",
+            691,
+            20
+          ],
+          Error: new Error()
+        };
       };
       return sub(List.length(l$1), l$1)[0];
     } else {
@@ -1472,15 +1454,14 @@ function pathsort(graph) {
     let stack = param[1];
     let set = param[0];
     if (mem(node, set)) {
-      throw new Error(Cycle, {
-        cause: {
-          RE_EXN_ID: Cycle,
-          _1: {
-            hd: node,
-            tl: stack
-          }
-        }
-      });
+      throw {
+        RE_EXN_ID: Cycle,
+        _1: {
+          hd: node,
+          tl: stack
+        },
+        Error: new Error()
+      };
     }
     return [
       add(node, set),
@@ -1525,16 +1506,15 @@ if (!Caml_obj.equal(pathsort(grwork), {
       }
     }
   })) {
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        144,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      144,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 try {
@@ -1545,16 +1525,15 @@ try {
     ],
     tl: grwork
   });
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "topsort_test.res",
-        148,
-        2
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "topsort_test.res",
+      148,
+      2
+    ],
+    Error: new Error()
+  };
 } catch (raw_exn) {
   let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
   let exit = 0;
@@ -1583,16 +1562,15 @@ try {
     exit = 1;
   }
   if (exit === 1) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "topsort_test.res",
-          151,
-          7
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "topsort_test.res",
+        151,
+        7
+      ],
+      Error: new Error()
+    };
   }
   
 }
diff --git a/jscomp/test/uncurried_cast.js b/jscomp/test/uncurried_cast.js
index 5ed7b4c208..92c87bf44b 100644
--- a/jscomp/test/uncurried_cast.js
+++ b/jscomp/test/uncurried_cast.js
@@ -5,9 +5,7 @@ let Belt_List = require("../../lib/js/belt_List.js");
 let Caml_exceptions = require("../../lib/js/caml_exceptions.js");
 
 function raise(e) {
-  throw new Error(e.RE_EXN_ID, {
-    cause: e
-  });
+  throw e;
 }
 
 let map = Belt_List.map;
@@ -24,11 +22,10 @@ let Uncurried = {
 let E = /* @__PURE__ */Caml_exceptions.create("Uncurried_cast.E");
 
 function testRaise() {
-  throw new Error(E, {
-    cause: {
-      RE_EXN_ID: E
-    }
-  });
+  throw {
+    RE_EXN_ID: E,
+    Error: new Error()
+  };
 }
 
 let l = Belt_List.map({
@@ -66,11 +63,10 @@ let StandardNotation = {
 };
 
 function testRaise$1() {
-  throw new Error(E, {
-    cause: {
-      RE_EXN_ID: E
-    }
-  });
+  throw {
+    RE_EXN_ID: E,
+    Error: new Error()
+  };
 }
 
 let l$1 = Belt_List.map({
diff --git a/jscomp/test/variant.js b/jscomp/test/variant.js
index d184ff6061..0ee7797d01 100644
--- a/jscomp/test/variant.js
+++ b/jscomp/test/variant.js
@@ -91,9 +91,7 @@ function rollback_path(subst, p) {
           return "Pident | Papply";
       }
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
 }
@@ -129,9 +127,7 @@ function fooExn(f) {
       let match = n._1;
       return match[0] + match[1] | 0;
     }
-    throw new Error(n.RE_EXN_ID, {
-      cause: n
-    });
+    throw n;
   }
 }
 
diff --git a/lib/es6/arg.js b/lib/es6/arg.js
index 865ef5a72a..a02eb4814e 100644
--- a/lib/es6/arg.js
+++ b/lib/es6/arg.js
@@ -31,11 +31,10 @@ function assoc3(x, _l) {
       _l = l.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -57,15 +56,14 @@ function make_symlist(prefix, sep, suffix, l) {
 }
 
 function help_action() {
-  throw new Error(Stop, {
-    cause: {
-      RE_EXN_ID: Stop,
-      _1: {
-        TAG: "Unknown",
-        _0: "-help"
-      }
-    }
-  });
+  throw {
+    RE_EXN_ID: Stop,
+    _1: {
+      TAG: "Unknown",
+      _0: "-help"
+    },
+    Error: new Error()
+  };
 }
 
 function add_help(speclist) {
@@ -88,9 +86,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
   let add2;
@@ -112,9 +108,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn$1.RE_EXN_ID, {
-        cause: exn$1
-      });
+      throw exn$1;
     }
   }
   return Pervasives.$at(speclist, Pervasives.$at(add1, add2));
@@ -159,9 +153,7 @@ function bool_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Invalid_argument") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -173,9 +165,7 @@ function int_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -187,9 +177,7 @@ function float_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -261,24 +249,19 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
             } catch (raw_exn$1) {
               let exn$1 = Caml_js_exceptions.internalToOCamlException(raw_exn$1);
               if (exn$1.RE_EXN_ID === "Not_found") {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Unknown",
-                      _0: s
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Unknown",
+                    _0: s
+                  },
+                  Error: new Error()
+                };
               }
-              throw new Error(exn$1.RE_EXN_ID, {
-                cause: exn$1
-              });
+              throw exn$1;
             }
           } else {
-            throw new Error(exn.RE_EXN_ID, {
-              cause: exn
-            });
+            throw exn;
           }
         }
         let follow = match[1];
@@ -286,17 +269,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
           if (follow === undefined) {
             return;
           }
-          throw new Error(Stop, {
-            cause: {
-              RE_EXN_ID: Stop,
-              _1: {
-                TAG: "Wrong",
-                _0: s,
-                _1: follow,
-                _2: "no argument"
-              }
-            }
-          });
+          throw {
+            RE_EXN_ID: Stop,
+            _1: {
+              TAG: "Wrong",
+              _0: s,
+              _1: follow,
+              _2: "no argument"
+            },
+            Error: new Error()
+          };
         };
         let get_arg = () => {
           if (follow !== undefined) {
@@ -305,15 +287,14 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
           if ((current.contents + 1 | 0) < argv.contents.length) {
             return Caml_array.get(argv.contents, current.contents + 1 | 0);
           }
-          throw new Error(Stop, {
-            cause: {
-              RE_EXN_ID: Stop,
-              _1: {
-                TAG: "Missing",
-                _0: s
-              }
-            }
-          });
+          throw {
+            RE_EXN_ID: Stop,
+            _1: {
+              TAG: "Missing",
+              _0: s
+            },
+            Error: new Error()
+          };
         };
         let consume_arg = () => {
           if (follow !== undefined) {
@@ -333,17 +314,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (s$1 !== undefined) {
                 f._0(s$1);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg,
-                      _2: "a boolean"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg,
+                    _2: "a boolean"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set" :
@@ -367,17 +347,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x !== undefined) {
                 f._0(x);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$2,
-                      _2: "an integer"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$2,
+                    _2: "an integer"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set_int" :
@@ -386,17 +365,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$1 !== undefined) {
                 f._0.contents = x$1;
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$3,
-                      _2: "an integer"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$3,
+                    _2: "an integer"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Float" :
@@ -405,17 +383,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$2 !== undefined) {
                 f._0(x$2);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$4,
-                      _2: "a float"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$4,
+                    _2: "a float"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set_float" :
@@ -424,17 +401,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$3 !== undefined) {
                 f._0.contents = x$3;
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$5,
-                      _2: "a float"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$5,
+                    _2: "a float"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Tuple" :
@@ -446,17 +422,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                 f._1(arg$6);
                 return consume_arg();
               }
-              throw new Error(Stop, {
-                cause: {
-                  RE_EXN_ID: Stop,
-                  _1: {
-                    TAG: "Wrong",
-                    _0: s,
-                    _1: arg$6,
-                    _2: "one of: " + make_symlist("", " ", "", symb)
-                  }
-                }
-              });
+              throw {
+                RE_EXN_ID: Stop,
+                _1: {
+                  TAG: "Wrong",
+                  _0: s,
+                  _1: arg$6,
+                  _2: "one of: " + make_symlist("", " ", "", symb)
+                },
+                Error: new Error()
+              };
             case "Rest" :
               let f$1 = f._0;
               while (current.contents < (argv.contents.length - 1 | 0)) {
@@ -466,12 +441,11 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               return;
             case "Expand" :
               if (!allow_expand) {
-                throw new Error("Invalid_argument", {
-                  cause: {
-                    RE_EXN_ID: "Invalid_argument",
-                    _1: "Arg.Expand is is only allowed with Arg.parse_and_expand_argv_dynamic"
-                  }
-                });
+                throw {
+                  RE_EXN_ID: "Invalid_argument",
+                  _1: "Arg.Expand is is only allowed with Arg.parse_and_expand_argv_dynamic",
+                  Error: new Error()
+                };
               }
               let arg$7 = get_arg();
               let newarg = f._0(arg$7);
@@ -498,24 +472,15 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
     } catch (raw_m) {
       let m = Caml_js_exceptions.internalToOCamlException(raw_m);
       if (m.RE_EXN_ID === Bad) {
-        throw new Error(convert_error({
+        throw convert_error({
           TAG: "Message",
           _0: m._1
-        }).RE_EXN_ID, {
-          cause: convert_error({
-            TAG: "Message",
-            _0: m._1
-          })
         });
       }
       if (m.RE_EXN_ID === Stop) {
-        throw new Error(convert_error(m._1).RE_EXN_ID, {
-          cause: convert_error(m._1)
-        });
+        throw convert_error(m._1);
       }
-      throw new Error(m.RE_EXN_ID, {
-        cause: m
-      });
+      throw m;
     }
     current.contents = current.contents + 1 | 0;
   };
@@ -552,9 +517,7 @@ function parse(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -571,9 +534,7 @@ function parse_dynamic(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -599,9 +560,7 @@ function parse_expand(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -636,18 +595,14 @@ function second_word(s) {
         if (exn$1.RE_EXN_ID === "Not_found") {
           return len;
         }
-        throw new Error(exn$1.RE_EXN_ID, {
-          cause: exn$1
-        });
+        throw exn$1;
       }
       if (exit === 2) {
         return loop(n$1 + 1 | 0);
       }
       
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
   return loop(n + 1 | 0);
diff --git a/lib/es6/array.js b/lib/es6/array.js
index e53c2c06d2..ff3b8d976d 100644
--- a/lib/es6/array.js
+++ b/lib/es6/array.js
@@ -14,12 +14,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f(0));
   for (let i = 1; i < l; ++i) {
@@ -58,24 +57,22 @@ function append(a1, a2) {
 
 function sub(a, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.sub",
+      Error: new Error()
+    };
   }
   return Caml_array.sub(a, ofs, len);
 }
 
 function fill(a, ofs, len, v) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.fill",
+      Error: new Error()
+    };
   }
   for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
     a[i] = v;
@@ -84,12 +81,11 @@ function fill(a, ofs, len, v) {
 
 function blit(a1, ofs1, a2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.blit",
+      Error: new Error()
+    };
   }
   Caml_array.blit(a1, ofs1, a2, ofs2, len);
 }
@@ -102,12 +98,11 @@ function iter(f, a) {
 
 function iter2(f, a, b) {
   if (a.length !== b.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.iter2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.iter2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
     f(a[i], b[i]);
@@ -130,12 +125,11 @@ function map2(f, a, b) {
   let la = a.length;
   let lb = b.length;
   if (la !== lb) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.map2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.map2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   if (la === 0) {
     return [];
@@ -317,12 +311,11 @@ function sort(cmp, a) {
     if (i31 < l) {
       return i31;
     }
-    throw new Error(Bottom, {
-      cause: {
-        RE_EXN_ID: Bottom,
-        _1: i
-      }
-    });
+    throw {
+      RE_EXN_ID: Bottom,
+      _1: i,
+      Error: new Error()
+    };
   };
   let trickle = (l, i, e) => {
     try {
@@ -342,9 +335,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return Caml_array.set(a, i$2._1, e);
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let bubble = (l, i) => {
@@ -362,9 +353,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return i$2._1;
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let trickleup = (_i, e) => {
@@ -372,16 +361,15 @@ function sort(cmp, a) {
       let i = _i;
       let father = (i - 1 | 0) / 3 | 0;
       if (i === father) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "array.res",
-              321,
-              4
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "array.res",
+            321,
+            4
+          ],
+          Error: new Error()
+        };
       }
       if (cmp(Caml_array.get(a, father), e) >= 0) {
         return Caml_array.set(a, i, e);
diff --git a/lib/es6/arrayLabels.js b/lib/es6/arrayLabels.js
index 4952c602c5..8832f68edb 100644
--- a/lib/es6/arrayLabels.js
+++ b/lib/es6/arrayLabels.js
@@ -14,12 +14,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f(0));
   for (let i = 1; i < l; ++i) {
@@ -58,24 +57,22 @@ function append(a1, a2) {
 
 function sub(a, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.sub",
+      Error: new Error()
+    };
   }
   return Caml_array.sub(a, ofs, len);
 }
 
 function fill(a, ofs, len, v) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.fill",
+      Error: new Error()
+    };
   }
   for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
     a[i] = v;
@@ -84,12 +81,11 @@ function fill(a, ofs, len, v) {
 
 function blit(a1, ofs1, a2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.blit",
+      Error: new Error()
+    };
   }
   Caml_array.blit(a1, ofs1, a2, ofs2, len);
 }
@@ -102,12 +98,11 @@ function iter(f, a) {
 
 function iter2(f, a, b) {
   if (a.length !== b.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.iter2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.iter2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
     f(a[i], b[i]);
@@ -130,12 +125,11 @@ function map2(f, a, b) {
   let la = a.length;
   let lb = b.length;
   if (la !== lb) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.map2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.map2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   if (la === 0) {
     return [];
@@ -317,12 +311,11 @@ function sort(cmp, a) {
     if (i31 < l) {
       return i31;
     }
-    throw new Error(Bottom, {
-      cause: {
-        RE_EXN_ID: Bottom,
-        _1: i
-      }
-    });
+    throw {
+      RE_EXN_ID: Bottom,
+      _1: i,
+      Error: new Error()
+    };
   };
   let trickle = (l, i, e) => {
     try {
@@ -342,9 +335,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return Caml_array.set(a, i$2._1, e);
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let bubble = (l, i) => {
@@ -362,9 +353,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return i$2._1;
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let trickleup = (_i, e) => {
@@ -372,16 +361,15 @@ function sort(cmp, a) {
       let i = _i;
       let father = (i - 1 | 0) / 3 | 0;
       if (i === father) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "arrayLabels.res",
-              321,
-              4
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "arrayLabels.res",
+            321,
+            4
+          ],
+          Error: new Error()
+        };
       }
       if (cmp(Caml_array.get(a, father), e) >= 0) {
         return Caml_array.set(a, i, e);
diff --git a/lib/es6/belt_Array.js b/lib/es6/belt_Array.js
index c3d940cbf5..52df9f4a28 100644
--- a/lib/es6/belt_Array.js
+++ b/lib/es6/belt_Array.js
@@ -12,16 +12,15 @@ function get(arr, i) {
 
 function getExn(arr, i) {
   if (!(i >= 0 && i < arr.length)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "belt_Array.res",
-          36,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "belt_Array.res",
+        36,
+        2
+      ],
+      Error: new Error()
+    };
   }
   return arr[i];
 }
@@ -37,16 +36,15 @@ function set(arr, i, v) {
 
 function setExn(arr, i, v) {
   if (!(i >= 0 && i < arr.length)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "belt_Array.res",
-          49,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "belt_Array.res",
+        49,
+        2
+      ],
+      Error: new Error()
+    };
   }
   arr[i] = v;
 }
diff --git a/lib/es6/belt_List.js b/lib/es6/belt_List.js
index a4c8e13787..219db44fc9 100644
--- a/lib/es6/belt_List.js
+++ b/lib/es6/belt_List.js
@@ -15,11 +15,10 @@ function headExn(x) {
   if (x) {
     return x.hd;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function tail(x) {
@@ -33,11 +32,10 @@ function tailExn(x) {
   if (x) {
     return x.tl;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function add(xs, x) {
@@ -71,11 +69,10 @@ function get(x, n) {
 
 function getExn(x, n) {
   if (n < 0) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let _x = x;
   let _n = n;
@@ -90,11 +87,10 @@ function getExn(x, n) {
       _x = x$1.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_MutableQueue.js b/lib/es6/belt_MutableQueue.js
index 40a4a0cc97..04f7171036 100644
--- a/lib/es6/belt_MutableQueue.js
+++ b/lib/es6/belt_MutableQueue.js
@@ -54,11 +54,10 @@ function peekExn(q) {
   if (v !== undefined) {
     return v.content;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function pop(q) {
@@ -90,11 +89,10 @@ function popExn(q) {
       return x.content;
     }
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function popUndefined(q) {
diff --git a/lib/es6/belt_Option.js b/lib/es6/belt_Option.js
index 12cb715f94..318e5e749e 100644
--- a/lib/es6/belt_Option.js
+++ b/lib/es6/belt_Option.js
@@ -20,11 +20,10 @@ function getExn(x) {
   if (x !== undefined) {
     return Caml_option.valFromOption(x);
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function mapWithDefault(opt, $$default, f) {
diff --git a/lib/es6/belt_Result.js b/lib/es6/belt_Result.js
index 90f1370d0e..54b73dcfa8 100644
--- a/lib/es6/belt_Result.js
+++ b/lib/es6/belt_Result.js
@@ -5,11 +5,10 @@ function getExn(x) {
   if (x.TAG === "Ok") {
     return x._0;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function mapWithDefault(opt, $$default, f) {
diff --git a/lib/es6/belt_internalAVLset.js b/lib/es6/belt_internalAVLset.js
index 3e680658a9..1306dda6c3 100644
--- a/lib/es6/belt_internalAVLset.js
+++ b/lib/es6/belt_internalAVLset.js
@@ -349,16 +349,15 @@ function checkInvariantInternal(_v) {
       r !== undefined ? r.h : 0
     ) | 0;
     if (!(diff <= 2 && diff >= -2)) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "belt_internalAVLset.res",
-            310,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "belt_internalAVLset.res",
+          310,
+          4
+        ],
+        Error: new Error()
+      };
     }
     checkInvariantInternal(l);
     _v = r;
@@ -700,11 +699,10 @@ function getExn(_n, x, cmp) {
       _n = c < 0 ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_internalAVLtree.js b/lib/es6/belt_internalAVLtree.js
index dcbd04e32e..37ee7a6a2f 100644
--- a/lib/es6/belt_internalAVLtree.js
+++ b/lib/es6/belt_internalAVLtree.js
@@ -546,16 +546,15 @@ function checkInvariantInternal(_v) {
     let r = v.r;
     let diff = treeHeight(l) - treeHeight(r) | 0;
     if (!(diff <= 2 && diff >= -2)) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "belt_internalAVLtree.res",
-            439,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "belt_internalAVLtree.res",
+          439,
+          4
+        ],
+        Error: new Error()
+      };
     }
     checkInvariantInternal(l);
     _v = r;
@@ -849,11 +848,10 @@ function getExn(_n, x, cmp) {
       _n = c < 0 ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_internalMapInt.js b/lib/es6/belt_internalMapInt.js
index 7f54f84751..4c3042dabb 100644
--- a/lib/es6/belt_internalMapInt.js
+++ b/lib/es6/belt_internalMapInt.js
@@ -62,11 +62,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_internalMapString.js b/lib/es6/belt_internalMapString.js
index d048bcc96f..3b98f118ff 100644
--- a/lib/es6/belt_internalMapString.js
+++ b/lib/es6/belt_internalMapString.js
@@ -62,11 +62,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_internalSetInt.js b/lib/es6/belt_internalSetInt.js
index 25243c2d97..1e5a5bb2c2 100644
--- a/lib/es6/belt_internalSetInt.js
+++ b/lib/es6/belt_internalSetInt.js
@@ -141,11 +141,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/belt_internalSetString.js b/lib/es6/belt_internalSetString.js
index cf752d348b..8de7f3eaff 100644
--- a/lib/es6/belt_internalSetString.js
+++ b/lib/es6/belt_internalSetString.js
@@ -141,11 +141,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/buffer.js b/lib/es6/buffer.js
index 13da86c768..09ba8d632d 100644
--- a/lib/es6/buffer.js
+++ b/lib/es6/buffer.js
@@ -26,36 +26,33 @@ function to_bytes(b) {
 
 function sub(b, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (b.position - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.sub",
+      Error: new Error()
+    };
   }
   return Bytes.sub_string(b.buffer, ofs, len);
 }
 
 function blit(src, srcoff, dst, dstoff, len) {
   if (len < 0 || srcoff < 0 || srcoff > (src.position - len | 0) || dstoff < 0 || dstoff > (dst.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.blit",
+      Error: new Error()
+    };
   }
   Bytes.blit(src.buffer, srcoff, dst, dstoff, len);
 }
 
 function nth(b, ofs) {
   if (ofs < 0 || ofs >= b.position) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.nth",
+      Error: new Error()
+    };
   }
   return b.buffer[ofs];
 }
@@ -98,16 +95,15 @@ function add_char(b, c) {
 function add_utf_8_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          98,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        98,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 127) {
     return add_char(b, u$1);
@@ -145,31 +141,29 @@ function add_utf_8_uchar(b, u) {
     b.position = pos$2 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        127,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      127,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_utf_16be_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          132,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        132,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 65535) {
     let pos = b.position;
@@ -196,31 +190,29 @@ function add_utf_16be_uchar(b, u) {
     b.position = pos$1 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        154,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      154,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_utf_16le_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          159,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        159,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 65535) {
     let pos = b.position;
@@ -247,26 +239,24 @@ function add_utf_16le_uchar(b, u) {
     b.position = pos$1 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        181,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      181,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_substring(b, s, offset, len) {
   if (offset < 0 || len < 0 || offset > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.add_substring/add_subbytes"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.add_substring/add_subbytes",
+      Error: new Error()
+    };
   }
   let new_position = b.position + len | 0;
   if (new_position > b.length) {
@@ -305,16 +295,15 @@ function closing(param) {
   if (param === 123) {
     return /* '}' */125;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        216,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      216,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function advance_to_closing(opening, closing, k, s, start) {
@@ -325,11 +314,10 @@ function advance_to_closing(opening, closing, k, s, start) {
     let i = _i;
     let k$1 = _k;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (Caml_string.get(s, i) === opening) {
       _i = i + 1 | 0;
@@ -383,11 +371,10 @@ function advance_to_non_alpha(s, start) {
 
 function find_ident(s, start, lim) {
   if (start >= lim) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let c = Caml_string.get(s, start);
   if (c !== 40 && c !== 123) {
@@ -455,12 +442,11 @@ function add_substitute(b, f, s) {
 
 function truncate(b, len) {
   if (len < 0 || len > b.position) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.truncate"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.truncate",
+      Error: new Error()
+    };
   }
   b.position = len;
 }
diff --git a/lib/es6/bytes.js b/lib/es6/bytes.js
index ef34d50b27..518ae3c793 100644
--- a/lib/es6/bytes.js
+++ b/lib/es6/bytes.js
@@ -110,12 +110,11 @@ function of_string(s) {
 
 function sub(s, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.sub / Bytes.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.sub / Bytes.sub",
+      Error: new Error()
+    };
   }
   let r = Caml_bytes.create(len);
   unsafe_blit(s, ofs, r, 0, len);
@@ -138,23 +137,21 @@ function $plus$plus(a, b) {
     if (match$2) {
       return c;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   if (match$1) {
     return c;
   }
   if (match$2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   return c;
 }
@@ -180,36 +177,33 @@ function extend(s, left, right) {
 
 function fill(s, ofs, len, c) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.fill / Bytes.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.fill / Bytes.fill",
+      Error: new Error()
+    };
   }
   unsafe_fill(s, ofs, len, c);
 }
 
 function blit(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.blit",
+      Error: new Error()
+    };
   }
   unsafe_blit(s1, ofs1, s2, ofs2, len);
 }
 
 function blit_string(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.blit / Bytes.blit_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.blit / Bytes.blit_string",
+      Error: new Error()
+    };
   }
   if (len <= 0) {
     return;
@@ -245,12 +239,11 @@ function ensure_ge(x, y) {
   if (x >= y) {
     return x;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Bytes.concat"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Bytes.concat",
+    Error: new Error()
+  };
 }
 
 function sum_lengths(_acc, seplen, _param) {
@@ -489,11 +482,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -528,12 +520,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -541,12 +532,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -555,11 +545,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -575,12 +564,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -605,12 +593,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -618,12 +605,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -633,9 +619,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -645,12 +629,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -660,9 +643,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/bytesLabels.js b/lib/es6/bytesLabels.js
index ef34d50b27..518ae3c793 100644
--- a/lib/es6/bytesLabels.js
+++ b/lib/es6/bytesLabels.js
@@ -110,12 +110,11 @@ function of_string(s) {
 
 function sub(s, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.sub / Bytes.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.sub / Bytes.sub",
+      Error: new Error()
+    };
   }
   let r = Caml_bytes.create(len);
   unsafe_blit(s, ofs, r, 0, len);
@@ -138,23 +137,21 @@ function $plus$plus(a, b) {
     if (match$2) {
       return c;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   if (match$1) {
     return c;
   }
   if (match$2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   return c;
 }
@@ -180,36 +177,33 @@ function extend(s, left, right) {
 
 function fill(s, ofs, len, c) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.fill / Bytes.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.fill / Bytes.fill",
+      Error: new Error()
+    };
   }
   unsafe_fill(s, ofs, len, c);
 }
 
 function blit(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.blit",
+      Error: new Error()
+    };
   }
   unsafe_blit(s1, ofs1, s2, ofs2, len);
 }
 
 function blit_string(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.blit / Bytes.blit_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.blit / Bytes.blit_string",
+      Error: new Error()
+    };
   }
   if (len <= 0) {
     return;
@@ -245,12 +239,11 @@ function ensure_ge(x, y) {
   if (x >= y) {
     return x;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Bytes.concat"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Bytes.concat",
+    Error: new Error()
+  };
 }
 
 function sum_lengths(_acc, seplen, _param) {
@@ -489,11 +482,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -528,12 +520,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -541,12 +532,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -555,11 +545,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -575,12 +564,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -605,12 +593,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -618,12 +605,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -633,9 +619,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -645,12 +629,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -660,9 +643,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/caml_array.js b/lib/es6/caml_array.js
index 692a92b75e..c9d8e3c8b0 100644
--- a/lib/es6/caml_array.js
+++ b/lib/es6/caml_array.js
@@ -57,24 +57,22 @@ function concat(l) {
 
 function set(xs, index, newval) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   xs[index] = newval;
 }
 
 function get(xs, index) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return xs[index];
 }
diff --git a/lib/es6/caml_bigint.js b/lib/es6/caml_bigint.js
index bdac616c54..098bf20b67 100644
--- a/lib/es6/caml_bigint.js
+++ b/lib/es6/caml_bigint.js
@@ -3,22 +3,20 @@
 
 function div(x, y) {
   if (y === 0n) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x / y;
 }
 
 function mod_(x, y) {
   if (y === 0n) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x % y;
 }
diff --git a/lib/es6/caml_bytes.js b/lib/es6/caml_bytes.js
index 72ae5a5032..86d784b8cf 100644
--- a/lib/es6/caml_bytes.js
+++ b/lib/es6/caml_bytes.js
@@ -3,36 +3,33 @@
 
 function set(s, i, ch) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   s[i] = ch;
 }
 
 function get(s, i) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return s[i];
 }
 
 function create(len) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.create"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.create",
+      Error: new Error()
+    };
   }
   let result = new Array(len);
   for (let i = 0; i < len; ++i) {
diff --git a/lib/es6/caml_format.js b/lib/es6/caml_format.js
index e0441baf86..4a806955d6 100644
--- a/lib/es6/caml_format.js
+++ b/lib/es6/caml_format.js
@@ -129,12 +129,11 @@ function int_of_string(s) {
   let c = i < len ? s.codePointAt(i) : /* '\000' */0;
   let d = parse_digit(c);
   if (d < 0 || d >= base) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int_of_string",
+      Error: new Error()
+    };
   }
   let aux = (_acc, _k) => {
     while (true) {
@@ -150,21 +149,19 @@ function int_of_string(s) {
       }
       let v = parse_digit(a);
       if (v < 0 || v >= base) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int_of_string",
+          Error: new Error()
+        };
       }
       let acc$1 = base * acc + v;
       if (acc$1 > threshold) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int_of_string",
+          Error: new Error()
+        };
       }
       _k = k + 1 | 0;
       _acc = acc$1;
@@ -174,12 +171,11 @@ function int_of_string(s) {
   let res = match[1] * aux(d, i + 1 | 0);
   let or_res = res | 0;
   if (base === 10 && res !== or_res) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int_of_string",
+      Error: new Error()
+    };
   }
   return or_res;
 }
@@ -218,12 +214,11 @@ function int64_of_string(s) {
   let c = i < len ? s.codePointAt(i) : /* '\000' */0;
   let d = Caml_int64.of_int32(parse_digit(c));
   if (Caml.i64_lt(d, Caml_int64.zero) || Caml.i64_ge(d, base)) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int64_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int64_of_string",
+      Error: new Error()
+    };
   }
   let aux = (_acc, _k) => {
     while (true) {
@@ -239,12 +234,11 @@ function int64_of_string(s) {
       }
       let v = Caml_int64.of_int32(parse_digit(a));
       if (Caml.i64_lt(v, Caml_int64.zero) || Caml.i64_ge(v, base) || Caml.i64_gt(acc, threshold)) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int64_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int64_of_string",
+          Error: new Error()
+        };
       }
       let acc$1 = Caml_int64.add(Caml_int64.mul(base, acc), v);
       _k = k + 1 | 0;
@@ -258,12 +252,11 @@ function int64_of_string(s) {
       0,
       10
     ]) && Caml.i64_neq(res, or_res)) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int64_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int64_of_string",
+      Error: new Error()
+    };
   }
   return or_res;
 }
@@ -290,12 +283,11 @@ function lowercase(c) {
 function parse_format(fmt) {
   let len = fmt.length;
   if (len > 31) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "format_int: format too long"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "format_int: format too long",
+      Error: new Error()
+    };
   }
   let f = {
     justify: "+",
@@ -773,7 +765,7 @@ let float_of_string = (function(s,exn){
         return Infinity;
     if (/^-inf(inity)?$/i.test(s))
         return -Infinity;
-    throw new Error(exn.RE_EXN_ID, { cause: exn });;
+    throw exn;
 });
 
 function float_of_string$1(s) {
diff --git a/lib/es6/caml_int32.js b/lib/es6/caml_int32.js
index b5cd97b472..adc5a19e40 100644
--- a/lib/es6/caml_int32.js
+++ b/lib/es6/caml_int32.js
@@ -3,22 +3,20 @@
 
 function div(x, y) {
   if (y === 0) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x / y | 0;
 }
 
 function mod_(x, y) {
   if (y === 0) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x % y;
 }
diff --git a/lib/es6/caml_int64.js b/lib/es6/caml_int64.js
index 7e0be85c45..2ad58e6cf4 100644
--- a/lib/es6/caml_int64.js
+++ b/lib/es6/caml_int64.js
@@ -383,11 +383,10 @@ function div(_self, _other) {
     if (other[0] !== 0 || other[1] !== 0) {
       exit$1 = 2;
     } else {
-      throw new Error("Division_by_zero", {
-        cause: {
-          RE_EXN_ID: "Division_by_zero"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Division_by_zero",
+        Error: new Error()
+      };
     }
     if (exit$1 === 2) {
       if (self_hi !== -2147483648) {
diff --git a/lib/es6/caml_js_exceptions.js b/lib/es6/caml_js_exceptions.js
index dccd3a3a10..8c89bc2438 100644
--- a/lib/es6/caml_js_exceptions.js
+++ b/lib/es6/caml_js_exceptions.js
@@ -6,8 +6,8 @@ import * as Caml_exceptions from "./caml_exceptions.js";
 let $$Error = "JsError";
 
 function internalToOCamlException(e) {
-  if (Caml_exceptions.is_extension(e.cause)) {
-    return e.cause;
+  if (Caml_exceptions.is_extension(e)) {
+    return e;
   } else {
     return {
       RE_EXN_ID: "JsError",
diff --git a/lib/es6/caml_lexer.js b/lib/es6/caml_lexer.js
index b50a5a45f6..a1ad028fd3 100644
--- a/lib/es6/caml_lexer.js
+++ b/lib/es6/caml_lexer.js
@@ -87,7 +87,7 @@ let caml_lex_engine_aux = (function (tbl, start_state, lexbuf, exn){
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn })
+                throw exn
             else
                 return lexbuf.lex_last_action;
         }
@@ -222,7 +222,7 @@ let caml_new_lex_engine_aux = (function (tbl, start_state, lexbuf, exn) {
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn });
+                throw exn;
             else
                 return lexbuf.lex_last_action;
         }
diff --git a/lib/es6/caml_module.js b/lib/es6/caml_module.js
index 51988ea254..09f354ec2e 100644
--- a/lib/es6/caml_module.js
+++ b/lib/es6/caml_module.js
@@ -4,12 +4,11 @@ import * as Caml_obj from "./caml_obj.js";
 
 function init_mod(loc, shape) {
   let undef_module = param => {
-    throw new Error("Undefined_recursive_module", {
-      cause: {
-        RE_EXN_ID: "Undefined_recursive_module",
-        _1: loc
-      }
-    });
+    throw {
+      RE_EXN_ID: "Undefined_recursive_module",
+      _1: loc,
+      Error: new Error()
+    };
   };
   let loop = (shape, struct_, idx) => {
     if (typeof shape !== "object") {
@@ -74,16 +73,15 @@ function update_mod(shape, o, n) {
     }
   };
   if (typeof shape !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "caml_module.res",
-          109,
-          9
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "caml_module.res",
+        109,
+        9
+      ],
+      Error: new Error()
+    };
   }
   if (shape.TAG === "Module") {
     let comps = shape._0;
@@ -94,16 +92,15 @@ function update_mod(shape, o, n) {
     }
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "caml_module.res",
-        109,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "caml_module.res",
+      109,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 export {
diff --git a/lib/es6/caml_obj.js b/lib/es6/caml_obj.js
index 9d025bf517..cf871f8a91 100644
--- a/lib/es6/caml_obj.js
+++ b/lib/es6/caml_obj.js
@@ -55,12 +55,11 @@ function compare(a, b) {
       break;
     case "function" :
       if (b_type === "function") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "compare: functional value"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "compare: functional value",
+          Error: new Error()
+        };
       }
       break;
     case "number" :
@@ -136,12 +135,11 @@ function compare(a, b) {
         return Caml.int_compare(a[1], b[1]);
       }
       if (tag_a === 251) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "equal: abstract value"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "equal: abstract value",
+          Error: new Error()
+        };
       }
       if (tag_a !== tag_b) {
         if (tag_a < tag_b) {
@@ -262,12 +260,11 @@ function equal(a, b) {
   }
   let b_type = typeof b;
   if (a_type === "function" || b_type === "function") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "equal: functional value"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "equal: functional value",
+      Error: new Error()
+    };
   }
   if (b_type === "number" || b_type === "bigint" || b_type === "undefined" || b === null) {
     return false;
@@ -278,12 +275,11 @@ function equal(a, b) {
     return a[1] === b[1];
   }
   if (tag_a === 251) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "equal: abstract value"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "equal: abstract value",
+      Error: new Error()
+    };
   }
   if (tag_a !== tag_b) {
     return false;
diff --git a/lib/es6/caml_string.js b/lib/es6/caml_string.js
index 8fe93ba893..741ccb6ddf 100644
--- a/lib/es6/caml_string.js
+++ b/lib/es6/caml_string.js
@@ -3,12 +3,11 @@
 
 function get(s, i) {
   if (i >= s.length || i < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return s.codePointAt(i);
 }
diff --git a/lib/es6/caml_sys.js b/lib/es6/caml_sys.js
index c1b42a6668..864a14fabf 100644
--- a/lib/es6/caml_sys.js
+++ b/lib/es6/caml_sys.js
@@ -3,21 +3,19 @@
 
 function sys_getenv(s) {
   if (typeof process === "undefined" || process.env === undefined) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let x = process.env[s];
   if (x !== undefined) {
     return x;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let os_type = (function(_){
@@ -73,21 +71,19 @@ function sys_exit(exit_code) {
 }
 
 function sys_is_directory(_s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "sys_is_directory not implemented"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "sys_is_directory not implemented",
+    Error: new Error()
+  };
 }
 
 function sys_file_exists(_s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "sys_file_exists not implemented"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "sys_file_exists not implemented",
+    Error: new Error()
+  };
 }
 
 export {
diff --git a/lib/es6/camlinternalLazy.js b/lib/es6/camlinternalLazy.js
index 59fa0b914d..c6dbdc0c20 100644
--- a/lib/es6/camlinternalLazy.js
+++ b/lib/es6/camlinternalLazy.js
@@ -16,11 +16,10 @@ function forward_with_closure(blk, closure) {
 }
 
 function raise_undefined() {
-  throw new Error(Undefined, {
-    cause: {
-      RE_EXN_ID: Undefined
-    }
-  });
+  throw {
+    RE_EXN_ID: Undefined,
+    Error: new Error()
+  };
 }
 
 function force(lzv) {
@@ -33,13 +32,9 @@ function force(lzv) {
       return forward_with_closure(lzv, closure);
     } catch (e) {
       lzv.VAL = () => {
-        throw new Error(e.RE_EXN_ID, {
-          cause: e
-        });
+        throw e;
       };
-      throw new Error(e.RE_EXN_ID, {
-        cause: e
-      });
+      throw e;
     }
   }
 }
diff --git a/lib/es6/char.js b/lib/es6/char.js
index f9da73cd4f..79cec11931 100644
--- a/lib/es6/char.js
+++ b/lib/es6/char.js
@@ -4,12 +4,11 @@ import * as Bytes from "./bytes.js";
 
 function chr(n) {
   if (n < 0 || n > 255) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Char.chr"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Char.chr",
+      Error: new Error()
+    };
   }
   return n;
 }
diff --git a/lib/es6/digest.js b/lib/es6/digest.js
index 1eded13e8a..3226f12277 100644
--- a/lib/es6/digest.js
+++ b/lib/es6/digest.js
@@ -17,12 +17,11 @@ function bytes(b) {
 
 function substring(str, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (str.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.substring"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.substring",
+      Error: new Error()
+    };
   }
   return Caml_md5.md5_string(str, ofs, len);
 }
@@ -39,12 +38,11 @@ function char_hex(n) {
 
 function to_hex(d) {
   if (d.length !== 16) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.to_hex"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.to_hex",
+      Error: new Error()
+    };
   }
   let result = Caml_bytes.create(32);
   for (let i = 0; i <= 15; ++i) {
@@ -57,43 +55,39 @@ function to_hex(d) {
 
 function from_hex(s) {
   if (s.length !== 32) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.from_hex"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.from_hex",
+      Error: new Error()
+    };
   }
   let digit = c => {
     if (c >= 65) {
       if (c >= 97) {
         if (c >= 103) {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Digest.from_hex"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Digest.from_hex",
+            Error: new Error()
+          };
         }
         return (c - /* 'a' */97 | 0) + 10 | 0;
       }
       if (c >= 71) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Digest.from_hex"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Digest.from_hex",
+          Error: new Error()
+        };
       }
       return (c - /* 'A' */65 | 0) + 10 | 0;
     }
     if (c > 57 || c < 48) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Digest.from_hex"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Digest.from_hex",
+        Error: new Error()
+      };
     }
     return c - /* '0' */48 | 0;
   };
diff --git a/lib/es6/filename.js b/lib/es6/filename.js
index 38a8258878..c186255abe 100644
--- a/lib/es6/filename.js
+++ b/lib/es6/filename.js
@@ -123,9 +123,7 @@ try {
   if (exn.RE_EXN_ID === "Not_found") {
     temp_dir_name = "/tmp";
   } else {
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -205,9 +203,7 @@ try {
   if (exn$1.RE_EXN_ID === "Not_found") {
     temp_dir_name$1 = ".";
   } else {
-    throw new Error(exn$1.RE_EXN_ID, {
-      cause: exn$1
-    });
+    throw exn$1;
   }
 }
 
@@ -382,12 +378,11 @@ function concat(dirname, filename) {
 function chop_suffix(name, suff) {
   let n = name.length - suff.length | 0;
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Filename.chop_suffix"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Filename.chop_suffix",
+      Error: new Error()
+    };
   }
   return $$String.sub(name, 0, n);
 }
@@ -430,12 +425,11 @@ function extension(name) {
 function chop_extension(name) {
   let l = extension_len(name);
   if (l === 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Filename.chop_extension"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Filename.chop_extension",
+      Error: new Error()
+    };
   }
   return $$String.sub(name, 0, name.length - l | 0);
 }
diff --git a/lib/es6/genlex.js b/lib/es6/genlex.js
index d3d551a979..72c88899ec 100644
--- a/lib/es6/genlex.js
+++ b/lib/es6/genlex.js
@@ -58,9 +58,7 @@ function make_lexer(keywords) {
           _0: id
         };
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   let keyword_or_error = c => {
@@ -70,16 +68,13 @@ function make_lexer(keywords) {
     } catch (raw_exn) {
       let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
       if (exn.RE_EXN_ID === "Not_found") {
-        throw new Error(Stream.$$Error, {
-          cause: {
-            RE_EXN_ID: Stream.$$Error,
-            _1: "Illegal character " + s
-          }
-        });
+        throw {
+          RE_EXN_ID: Stream.$$Error,
+          _1: "Illegal character " + s,
+          Error: new Error()
+        };
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   let next_token = strm__ => {
@@ -118,26 +113,22 @@ function make_lexer(keywords) {
                 } catch (raw_exn) {
                   let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
                   if (exn.RE_EXN_ID === Stream.Failure) {
-                    throw new Error(Stream.$$Error, {
-                      cause: {
-                        RE_EXN_ID: Stream.$$Error,
-                        _1: ""
-                      }
-                    });
+                    throw {
+                      RE_EXN_ID: Stream.$$Error,
+                      _1: "",
+                      Error: new Error()
+                    };
                   }
-                  throw new Error(exn.RE_EXN_ID, {
-                    cause: exn
-                  });
+                  throw exn;
                 }
                 let match = Stream.peek(strm__);
                 if (match !== undefined) {
                   if (match !== 39) {
-                    throw new Error(Stream.$$Error, {
-                      cause: {
-                        RE_EXN_ID: Stream.$$Error,
-                        _1: ""
-                      }
-                    });
+                    throw {
+                      RE_EXN_ID: Stream.$$Error,
+                      _1: "",
+                      Error: new Error()
+                    };
                   }
                   Stream.junk(strm__);
                   return {
@@ -145,12 +136,11 @@ function make_lexer(keywords) {
                     _0: c$1
                   };
                 }
-                throw new Error(Stream.$$Error, {
-                  cause: {
-                    RE_EXN_ID: Stream.$$Error,
-                    _1: ""
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stream.$$Error,
+                  _1: "",
+                  Error: new Error()
+                };
               case 40 :
                 Stream.junk(strm__);
                 let match$1 = Stream.peek(strm__);
@@ -473,16 +463,13 @@ function make_lexer(keywords) {
           } catch (raw_exn) {
             let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
             if (exn.RE_EXN_ID === Stream.Failure) {
-              throw new Error(Stream.$$Error, {
-                cause: {
-                  RE_EXN_ID: Stream.$$Error,
-                  _1: ""
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.$$Error,
+                _1: "",
+                Error: new Error()
+              };
             }
-            throw new Error(exn.RE_EXN_ID, {
-              cause: exn
-            });
+            throw exn;
           }
           store(c$1);
           continue;
@@ -490,11 +477,10 @@ function make_lexer(keywords) {
         Stream.junk(strm__);
         return get_string();
       }
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     };
   };
   let char = strm__ => {
@@ -510,23 +496,19 @@ function make_lexer(keywords) {
       } catch (raw_exn) {
         let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
         if (exn.RE_EXN_ID === Stream.Failure) {
-          throw new Error(Stream.$$Error, {
-            cause: {
-              RE_EXN_ID: Stream.$$Error,
-              _1: ""
-            }
-          });
+          throw {
+            RE_EXN_ID: Stream.$$Error,
+            _1: "",
+            Error: new Error()
+          };
         }
-        throw new Error(exn.RE_EXN_ID, {
-          cause: exn
-        });
+        throw exn;
       }
     } else {
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     }
   };
   let escape = strm__ => {
@@ -553,50 +535,45 @@ function make_lexer(keywords) {
           let c2 = Stream.peek(strm__);
           if (c2 !== undefined) {
             if (c2 > 57 || c2 < 48) {
-              throw new Error(Stream.$$Error, {
-                cause: {
-                  RE_EXN_ID: Stream.$$Error,
-                  _1: ""
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.$$Error,
+                _1: "",
+                Error: new Error()
+              };
             }
             Stream.junk(strm__);
             let c3 = Stream.peek(strm__);
             if (c3 !== undefined) {
               if (c3 > 57 || c3 < 48) {
-                throw new Error(Stream.$$Error, {
-                  cause: {
-                    RE_EXN_ID: Stream.$$Error,
-                    _1: ""
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stream.$$Error,
+                  _1: "",
+                  Error: new Error()
+                };
               }
               Stream.junk(strm__);
               return Char.chr((Math.imul(c1 - 48 | 0, 100) + Math.imul(c2 - 48 | 0, 10) | 0) + (c3 - 48 | 0) | 0);
             }
-            throw new Error(Stream.$$Error, {
-              cause: {
-                RE_EXN_ID: Stream.$$Error,
-                _1: ""
-              }
-            });
-          }
-          throw new Error(Stream.$$Error, {
-            cause: {
+            throw {
               RE_EXN_ID: Stream.$$Error,
-              _1: ""
-            }
-          });
+              _1: "",
+              Error: new Error()
+            };
+          }
+          throw {
+            RE_EXN_ID: Stream.$$Error,
+            _1: "",
+            Error: new Error()
+          };
         }
         Stream.junk(strm__);
         return c1;
       }
     } else {
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     }
   };
   let comment = strm__ => {
@@ -617,11 +594,10 @@ function make_lexer(keywords) {
                 return comment(strm__);
               }
             }
-            throw new Error(Stream.Failure, {
-              cause: {
-                RE_EXN_ID: Stream.Failure
-              }
-            });
+            throw {
+              RE_EXN_ID: Stream.Failure,
+              Error: new Error()
+            };
           case 42 :
             Stream.junk(strm__);
             while (true) {
@@ -638,22 +614,20 @@ function make_lexer(keywords) {
                 Stream.junk(strm__);
                 return;
               }
-              throw new Error(Stream.Failure, {
-                cause: {
-                  RE_EXN_ID: Stream.Failure
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.Failure,
+                Error: new Error()
+              };
             };
           default:
             Stream.junk(strm__);
             continue;
         }
       } else {
-        throw new Error(Stream.Failure, {
-          cause: {
-            RE_EXN_ID: Stream.Failure
-          }
-        });
+        throw {
+          RE_EXN_ID: Stream.Failure,
+          Error: new Error()
+        };
       }
     };
   };
diff --git a/lib/es6/hashtbl.js b/lib/es6/hashtbl.js
index 4337892b11..f7b49ab4a7 100644
--- a/lib/es6/hashtbl.js
+++ b/lib/es6/hashtbl.js
@@ -109,16 +109,15 @@ function copy_bucketlist(param) {
         next: next
       };
       if (typeof prec !== "object") {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "hashtbl.res",
-              110,
-              19
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "hashtbl.res",
+            110,
+            19
+          ],
+          Error: new Error()
+        };
       }
       prec.next = r;
       _param = next;
@@ -252,11 +251,10 @@ function remove(h, key) {
 function find(h, key) {
   let match = Caml_array.get(h.data, key_index(h, key));
   if (typeof match !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k1 = match.key;
   let d1 = match.data;
@@ -265,11 +263,10 @@ function find(h, key) {
     return d1;
   }
   if (typeof next1 !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k2 = next1.key;
   let d2 = next1.data;
@@ -278,11 +275,10 @@ function find(h, key) {
     return d2;
   }
   if (typeof next2 !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k3 = next2.key;
   let d3 = next2.data;
@@ -294,11 +290,10 @@ function find(h, key) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let k = param.key;
       let data = param.data;
@@ -468,14 +463,10 @@ function iter(f, h) {
     }
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -525,14 +516,10 @@ function filter_map_inplace(f, h) {
     return;
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -568,14 +555,10 @@ function fold(f, h, init) {
     return accu;
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -654,11 +637,10 @@ function MakeSeeded(H) {
   let find = (h, key) => {
     let match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k1 = match.key;
     let d1 = match.data;
@@ -667,11 +649,10 @@ function MakeSeeded(H) {
       return d1;
     }
     if (typeof next1 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k2 = next1.key;
     let d2 = next1.data;
@@ -680,11 +661,10 @@ function MakeSeeded(H) {
       return d2;
     }
     if (typeof next2 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k3 = next2.key;
     let d3 = next2.data;
@@ -696,11 +676,10 @@ function MakeSeeded(H) {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let k = param.key;
         let data = param.data;
@@ -900,11 +879,10 @@ function Make(H) {
   let find = (h, key) => {
     let match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k1 = match.key;
     let d1 = match.data;
@@ -913,11 +891,10 @@ function Make(H) {
       return d1;
     }
     if (typeof next1 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k2 = next1.key;
     let d2 = next1.data;
@@ -926,11 +903,10 @@ function Make(H) {
       return d2;
     }
     if (typeof next2 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k3 = next2.key;
     let d3 = next2.data;
@@ -942,11 +918,10 @@ function Make(H) {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let k = param.key;
         let data = param.data;
diff --git a/lib/es6/int32.js b/lib/es6/int32.js
index 044b7687ef..dff650c3e9 100644
--- a/lib/es6/int32.js
+++ b/lib/es6/int32.js
@@ -36,9 +36,7 @@ function of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/int64.js b/lib/es6/int64.js
index 1c102d7b2f..37fd9241c7 100644
--- a/lib/es6/int64.js
+++ b/lib/es6/int64.js
@@ -29,9 +29,7 @@ function of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/js_exn.js b/lib/es6/js_exn.js
index 5d9a1f8fa9..74add0dd3a 100644
--- a/lib/es6/js_exn.js
+++ b/lib/es6/js_exn.js
@@ -2,45 +2,31 @@
 
 
 function raiseError(str) {
-  throw new Error(new Error(str).RE_EXN_ID, {
-    cause: new Error(str)
-  });
+  throw new Error(str);
 }
 
 function raiseEvalError(str) {
-  throw new Error(new EvalError(str).RE_EXN_ID, {
-    cause: new EvalError(str)
-  });
+  throw new EvalError(str);
 }
 
 function raiseRangeError(str) {
-  throw new Error(new RangeError(str).RE_EXN_ID, {
-    cause: new RangeError(str)
-  });
+  throw new RangeError(str);
 }
 
 function raiseReferenceError(str) {
-  throw new Error(new ReferenceError(str).RE_EXN_ID, {
-    cause: new ReferenceError(str)
-  });
+  throw new ReferenceError(str);
 }
 
 function raiseSyntaxError(str) {
-  throw new Error(new SyntaxError(str).RE_EXN_ID, {
-    cause: new SyntaxError(str)
-  });
+  throw new SyntaxError(str);
 }
 
 function raiseTypeError(str) {
-  throw new Error(new TypeError(str).RE_EXN_ID, {
-    cause: new TypeError(str)
-  });
+  throw new TypeError(str);
 }
 
 function raiseUriError(str) {
-  throw new Error(new URIError(str).RE_EXN_ID, {
-    cause: new URIError(str)
-  });
+  throw new URIError(str);
 }
 
 let $$Error$1 = "JsError";
diff --git a/lib/es6/js_null.js b/lib/es6/js_null.js
index 4a30b70360..9ac6a94514 100644
--- a/lib/es6/js_null.js
+++ b/lib/es6/js_null.js
@@ -10,9 +10,7 @@ function getExn(f) {
   if (f !== null) {
     return f;
   }
-  throw new Error(new Error("Js.Null.getExn").RE_EXN_ID, {
-    cause: new Error("Js.Null.getExn")
-  });
+  throw new Error("Js.Null.getExn");
 }
 
 function bind(x, f) {
diff --git a/lib/es6/js_option.js b/lib/es6/js_option.js
index b24505acab..0667fcd74d 100644
--- a/lib/es6/js_option.js
+++ b/lib/es6/js_option.js
@@ -26,9 +26,7 @@ function getExn(x) {
   if (x !== undefined) {
     return Caml_option.valFromOption(x);
   }
-  throw new Error(new Error("getExn").RE_EXN_ID, {
-    cause: new Error("getExn")
-  });
+  throw new Error("getExn");
 }
 
 function equal(eq, a, b) {
diff --git a/lib/es6/js_undefined.js b/lib/es6/js_undefined.js
index 762283d3da..8d5125bc03 100644
--- a/lib/es6/js_undefined.js
+++ b/lib/es6/js_undefined.js
@@ -14,9 +14,7 @@ function getExn(f) {
   if (f !== undefined) {
     return f;
   }
-  throw new Error(new Error("Js.Undefined.getExn").RE_EXN_ID, {
-    cause: new Error("Js.Undefined.getExn")
-  });
+  throw new Error("Js.Undefined.getExn");
 }
 
 function bind(x, f) {
diff --git a/lib/es6/lexing.js b/lib/es6/lexing.js
index cb6ad1c864..33175bdb02 100644
--- a/lib/es6/lexing.js
+++ b/lib/es6/lexing.js
@@ -54,12 +54,11 @@ function from_function(f) {
         } else {
           let newlen = (x.lex_buffer.length << 1);
           if (((x.lex_buffer_len - x.lex_start_pos | 0) + n | 0) > newlen) {
-            throw new Error("Failure", {
-              cause: {
-                RE_EXN_ID: "Failure",
-                _1: "Lexing.lex_refill: cannot grow buffer"
-              }
-            });
+            throw {
+              RE_EXN_ID: "Failure",
+              _1: "Lexing.lex_refill: cannot grow buffer",
+              Error: new Error()
+            };
           }
           let newbuf = Caml_bytes.create(newlen);
           Bytes.blit(x.lex_buffer, x.lex_start_pos, newbuf, 0, x.lex_buffer_len - x.lex_start_pos | 0);
diff --git a/lib/es6/list.js b/lib/es6/list.js
index 09ebf99bde..0143699d17 100644
--- a/lib/es6/list.js
+++ b/lib/es6/list.js
@@ -30,34 +30,31 @@ function hd(param) {
   if (param) {
     return param.hd;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "hd"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "hd",
+    Error: new Error()
+  };
 }
 
 function tl(param) {
   if (param) {
     return param.tl;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "tl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "tl",
+    Error: new Error()
+  };
 }
 
 function nth(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -72,23 +69,21 @@ function nth(l, n) {
       _l = l$1.tl;
       continue;
     }
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "nth",
+      Error: new Error()
+    };
   };
 }
 
 function nth_opt(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -156,12 +151,11 @@ function init_aux(i, n, f) {
 
 function init(len, f) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.init",
+      Error: new Error()
+    };
   }
   if (len > 10000) {
     return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
@@ -280,22 +274,20 @@ function map2(f, l1, l2) {
         tl: map2(f, l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2",
+    Error: new Error()
+  };
 }
 
 function rev_map2(f, l1, l2) {
@@ -316,20 +308,18 @@ function rev_map2(f, l1, l2) {
         };
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     if (l2$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -346,22 +336,20 @@ function iter2(f, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.iter2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.iter2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.iter2",
+      Error: new Error()
+    };
   };
 }
 
@@ -377,20 +365,18 @@ function fold_left2(f, _accu, _l1, _l2) {
         _accu = f(accu, l1.hd, l2.hd);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     if (l2) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -401,20 +387,18 @@ function fold_right2(f, l1, l2, accu) {
     if (l2) {
       return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -460,22 +444,20 @@ function for_all2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.for_all2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.for_all2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return true;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.for_all2",
+      Error: new Error()
+    };
   };
 }
 
@@ -492,22 +474,20 @@ function exists2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.exists2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.exists2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return false;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.exists2",
+      Error: new Error()
+    };
   };
 }
 
@@ -550,11 +530,10 @@ function assoc(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -584,11 +563,10 @@ function assq(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -678,11 +656,10 @@ function find(p, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -790,22 +767,20 @@ function combine(l1, l2) {
         tl: combine(l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.combine"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.combine",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.combine",
+    Error: new Error()
+  };
 }
 
 function merge(cmp, l1, l2) {
@@ -842,16 +817,15 @@ function chop(_k, _l) {
       _k = k - 1 | 0;
       continue;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "list.res",
-          420,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "list.res",
+        420,
+        11
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/listLabels.js b/lib/es6/listLabels.js
index b614cbfc27..e85c6163f4 100644
--- a/lib/es6/listLabels.js
+++ b/lib/es6/listLabels.js
@@ -30,34 +30,31 @@ function hd(param) {
   if (param) {
     return param.hd;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "hd"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "hd",
+    Error: new Error()
+  };
 }
 
 function tl(param) {
   if (param) {
     return param.tl;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "tl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "tl",
+    Error: new Error()
+  };
 }
 
 function nth(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -72,23 +69,21 @@ function nth(l, n) {
       _l = l$1.tl;
       continue;
     }
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "nth",
+      Error: new Error()
+    };
   };
 }
 
 function nth_opt(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -156,12 +151,11 @@ function init_aux(i, n, f) {
 
 function init(len, f) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.init",
+      Error: new Error()
+    };
   }
   if (len > 10000) {
     return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
@@ -280,22 +274,20 @@ function map2(f, l1, l2) {
         tl: map2(f, l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2",
+    Error: new Error()
+  };
 }
 
 function rev_map2(f, l1, l2) {
@@ -316,20 +308,18 @@ function rev_map2(f, l1, l2) {
         };
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     if (l2$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -346,22 +336,20 @@ function iter2(f, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.iter2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.iter2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.iter2",
+      Error: new Error()
+    };
   };
 }
 
@@ -377,20 +365,18 @@ function fold_left2(f, _accu, _l1, _l2) {
         _accu = f(accu, l1.hd, l2.hd);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     if (l2) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -401,20 +387,18 @@ function fold_right2(f, l1, l2, accu) {
     if (l2) {
       return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -460,22 +444,20 @@ function for_all2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.for_all2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.for_all2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return true;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.for_all2",
+      Error: new Error()
+    };
   };
 }
 
@@ -492,22 +474,20 @@ function exists2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.exists2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.exists2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return false;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.exists2",
+      Error: new Error()
+    };
   };
 }
 
@@ -550,11 +530,10 @@ function assoc(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -584,11 +563,10 @@ function assq(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -678,11 +656,10 @@ function find(p, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -790,22 +767,20 @@ function combine(l1, l2) {
         tl: combine(l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.combine"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.combine",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.combine",
+    Error: new Error()
+  };
 }
 
 function merge(cmp, l1, l2) {
@@ -842,16 +817,15 @@ function chop(_k, _l) {
       _k = k - 1 | 0;
       continue;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "listLabels.res",
-          420,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "listLabels.res",
+        420,
+        11
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/es6/map.js b/lib/es6/map.js
index 2052415d99..6829c40962 100644
--- a/lib/es6/map.js
+++ b/lib/es6/map.js
@@ -37,12 +37,11 @@ function Make(funarg) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let ld = l.d;
@@ -54,12 +53,11 @@ function Make(funarg) {
       if (typeof lr === "object") {
         return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -72,12 +70,11 @@ function Make(funarg) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rd = r.d;
@@ -89,12 +86,11 @@ function Make(funarg) {
     if (typeof rl === "object") {
       return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   };
   let is_empty = param => {
     if (typeof param !== "object") {
@@ -152,11 +148,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = funarg.compare(x, param.v);
       if (c === 0) {
@@ -170,11 +165,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -246,11 +240,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -350,11 +343,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -388,11 +380,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -424,12 +415,11 @@ function Make(funarg) {
   };
   let remove_min_binding = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -717,16 +707,15 @@ function Make(funarg) {
       
     }
     if (typeof s2 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "map.res",
-            552,
-            11
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "map.res",
+          552,
+          11
+        ],
+        Error: new Error()
+      };
     }
     let v2 = s2.v;
     let match$1 = split(v2, s1);
diff --git a/lib/es6/mapLabels.js b/lib/es6/mapLabels.js
index c791c85f85..713328179b 100644
--- a/lib/es6/mapLabels.js
+++ b/lib/es6/mapLabels.js
@@ -37,12 +37,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let ld = l.d;
@@ -54,12 +53,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -72,12 +70,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rd = r.d;
@@ -89,12 +86,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   };
   let is_empty = param => {
     if (typeof param !== "object") {
@@ -152,11 +148,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = Ord.compare(x, param.v);
       if (c === 0) {
@@ -192,11 +187,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -268,11 +262,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -350,11 +343,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -388,11 +380,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -424,12 +415,11 @@ function Make(Ord) {
   };
   let remove_min_binding = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -717,16 +707,15 @@ function Make(Ord) {
       
     }
     if (typeof s2 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "mapLabels.res",
-            552,
-            11
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "mapLabels.res",
+          552,
+          11
+        ],
+        Error: new Error()
+      };
     }
     let v2 = s2.v;
     let match$1 = split(v2, s1);
diff --git a/lib/es6/moreLabels.js b/lib/es6/moreLabels.js
index 5ab48c2721..e42e900b6e 100644
--- a/lib/es6/moreLabels.js
+++ b/lib/es6/moreLabels.js
@@ -67,12 +67,11 @@ let $$Map = {
       hr = typeof r !== "object" ? 0 : r.h;
       if (hl > (hr + 2 | 0)) {
         if (typeof l !== "object") {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Map.bal"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Map.bal",
+            Error: new Error()
+          };
         }
         let lr = l.r;
         let ld = l.d;
@@ -84,12 +83,11 @@ let $$Map = {
         if (typeof lr === "object") {
           return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
         }
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       if (hr <= (hl + 2 | 0)) {
         return {
@@ -102,12 +100,11 @@ let $$Map = {
         };
       }
       if (typeof r !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let rr = r.r;
       let rd = r.d;
@@ -119,12 +116,11 @@ let $$Map = {
       if (typeof rl === "object") {
         return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     };
     let is_empty = param => {
       if (typeof param !== "object") {
@@ -182,11 +178,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let c = funarg.compare(x, param.v);
         if (c === 0) {
@@ -222,11 +217,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -298,11 +292,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -380,11 +373,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let l = param.l;
         if (typeof l !== "object") {
@@ -418,11 +410,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let r = param.r;
         if (typeof r !== "object") {
@@ -454,12 +445,11 @@ let $$Map = {
     };
     let remove_min_binding = param => {
       if (typeof param !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.remove_min_elt"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.remove_min_elt",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -747,16 +737,15 @@ let $$Map = {
         
       }
       if (typeof s2 !== "object") {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "mapLabels.res",
-              552,
-              11
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "mapLabels.res",
+            552,
+            11
+          ],
+          Error: new Error()
+        };
       }
       let v2 = s2.v;
       let match$1 = split(v2, s1);
@@ -1011,12 +1000,11 @@ let $$Set = {
       hr = typeof r !== "object" ? 0 : r.h;
       if (hl > (hr + 2 | 0)) {
         if (typeof l !== "object") {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Set.bal"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Set.bal",
+            Error: new Error()
+          };
         }
         let lr = l.r;
         let lv = l.v;
@@ -1027,12 +1015,11 @@ let $$Set = {
         if (typeof lr === "object") {
           return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
         }
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       if (hr <= (hl + 2 | 0)) {
         return {
@@ -1044,12 +1031,11 @@ let $$Set = {
         };
       }
       if (typeof r !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let rr = r.r;
       let rv = r.v;
@@ -1060,12 +1046,11 @@ let $$Set = {
       if (typeof rl === "object") {
         return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     };
     let add = (x, param) => {
       if (typeof param !== "object") {
@@ -1141,11 +1126,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let l = param.l;
         if (typeof l !== "object") {
@@ -1173,11 +1157,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let r = param.r;
         if (typeof r !== "object") {
@@ -1203,12 +1186,11 @@ let $$Set = {
     };
     let remove_min_elt = param => {
       if (typeof param !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.remove_min_elt"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.remove_min_elt",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -1598,11 +1580,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         let c = funarg.compare(x, v);
@@ -1634,11 +1615,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -1700,11 +1680,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -1874,16 +1853,15 @@ let $$Set = {
             match$4[1]
           ];
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "setLabels.res",
-              691,
-              20
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "setLabels.res",
+            691,
+            20
+          ],
+          Error: new Error()
+        };
       };
       return sub(List.length(l), l)[0];
     };
diff --git a/lib/es6/parsing.js b/lib/es6/parsing.js
index c2eb456f4f..e882967d42 100644
--- a/lib/es6/parsing.js
+++ b/lib/es6/parsing.js
@@ -85,11 +85,10 @@ function yyparse(tables, start, lexer, lexbuf) {
           _cmd = "Token_read";
           continue;
         case "Raise_parse_error" :
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         case "Grow_stacks_1" :
           grow_stacks();
           _arg = undefined;
@@ -115,9 +114,7 @@ function yyparse(tables, start, lexer, lexbuf) {
                 undefined
               ];
             } else {
-              throw new Error(exn.RE_EXN_ID, {
-                cause: exn
-              });
+              throw exn;
             }
           }
           _arg = match$1[1];
@@ -150,9 +147,7 @@ function yyparse(tables, start, lexer, lexbuf) {
         return Caml_array.get(tables.transl_const, tok) === curr_char;
       }
     };
-    throw new Error(exn$1.RE_EXN_ID, {
-      cause: exn$1
-    });
+    throw exn$1;
   }
 }
 
diff --git a/lib/es6/pervasives.js b/lib/es6/pervasives.js
index e066b6e51c..ef8e3d41a5 100644
--- a/lib/es6/pervasives.js
+++ b/lib/es6/pervasives.js
@@ -7,21 +7,19 @@ import * as Caml_exceptions from "./caml_exceptions.js";
 import * as Caml_js_exceptions from "./caml_js_exceptions.js";
 
 function failwith(s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function invalid_arg(s) {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 let Exit = /* @__PURE__ */Caml_exceptions.create("Pervasives.Exit");
@@ -58,12 +56,11 @@ function classify_float(x) {
 
 function char_of_int(n) {
   if (n < 0 || n > 255) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "char_of_int"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "char_of_int",
+      Error: new Error()
+    };
   }
   return n;
 }
@@ -83,12 +80,11 @@ function bool_of_string(param) {
     case "true" :
       return true;
     default:
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "bool_of_string"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "bool_of_string",
+        Error: new Error()
+      };
   }
 }
 
@@ -111,9 +107,7 @@ function int_of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -153,9 +147,7 @@ function float_of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/queue.js b/lib/es6/queue.js
index 72b301fa5f..060df8ec7e 100644
--- a/lib/es6/queue.js
+++ b/lib/es6/queue.js
@@ -41,21 +41,19 @@ function peek(q) {
   if (typeof match === "object") {
     return match.content;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function take(q) {
   let match = q.first;
   if (typeof match !== "object") {
-    throw new Error(Empty, {
-      cause: {
-        RE_EXN_ID: Empty
-      }
-    });
+    throw {
+      RE_EXN_ID: Empty,
+      Error: new Error()
+    };
   }
   let content = match.content;
   let next = match.next;
diff --git a/lib/es6/random.js b/lib/es6/random.js
index eecb439f2f..e73c109347 100644
--- a/lib/es6/random.js
+++ b/lib/es6/random.js
@@ -71,12 +71,11 @@ function bits(s) {
 
 function int(s, bound) {
   if (bound > 1073741823 || bound <= 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int",
+      Error: new Error()
+    };
   }
   while (true) {
     let r = bits(s);
@@ -90,12 +89,11 @@ function int(s, bound) {
 
 function int32(s, bound) {
   if (bound <= 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int32"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int32",
+      Error: new Error()
+    };
   }
   while (true) {
     let b1 = bits(s);
@@ -111,12 +109,11 @@ function int32(s, bound) {
 
 function int64(s, bound) {
   if (Caml.i64_le(bound, Caml_int64.zero)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int64"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int64",
+      Error: new Error()
+    };
   }
   while (true) {
     let b1 = Caml_int64.of_int32(bits(s));
diff --git a/lib/es6/runtime_deriving.js b/lib/es6/runtime_deriving.js
index 36b9eb01d8..a5299e3648 100644
--- a/lib/es6/runtime_deriving.js
+++ b/lib/es6/runtime_deriving.js
@@ -3,11 +3,10 @@
 
 function raiseWhenNotFound(x) {
   if (x == null) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   return x;
 }
diff --git a/lib/es6/set.js b/lib/es6/set.js
index 214de70318..dbebe6a6a9 100644
--- a/lib/es6/set.js
+++ b/lib/es6/set.js
@@ -31,12 +31,11 @@ function Make(funarg) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let lv = l.v;
@@ -47,12 +46,11 @@ function Make(funarg) {
       if (typeof lr === "object") {
         return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -64,12 +62,11 @@ function Make(funarg) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rv = r.v;
@@ -80,12 +77,11 @@ function Make(funarg) {
     if (typeof rl === "object") {
       return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   };
   let add = (x, param) => {
     if (typeof param !== "object") {
@@ -161,11 +157,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -193,11 +188,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -223,12 +217,11 @@ function Make(funarg) {
   };
   let remove_min_elt = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -616,11 +609,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       let c = funarg.compare(x, v);
@@ -635,11 +627,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -699,11 +690,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -906,16 +896,15 @@ function Make(funarg) {
               match$4[1]
             ];
           }
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "set.res",
-                691,
-                20
-              ]
-            }
-          });
+          throw {
+            RE_EXN_ID: "Assert_failure",
+            _1: [
+              "set.res",
+              691,
+              20
+            ],
+            Error: new Error()
+          };
         };
         return sub(List.length(l$1), l$1)[0];
       } else {
diff --git a/lib/es6/setLabels.js b/lib/es6/setLabels.js
index 604cad1ec7..f803387202 100644
--- a/lib/es6/setLabels.js
+++ b/lib/es6/setLabels.js
@@ -31,12 +31,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let lv = l.v;
@@ -47,12 +46,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -64,12 +62,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rv = r.v;
@@ -80,12 +77,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   };
   let add = (x, param) => {
     if (typeof param !== "object") {
@@ -161,11 +157,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -193,11 +188,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -223,12 +217,11 @@ function Make(Ord) {
   };
   let remove_min_elt = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -618,11 +611,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       let c = Ord.compare(x, v);
@@ -654,11 +646,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -720,11 +711,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -894,16 +884,15 @@ function Make(Ord) {
           match$4[1]
         ];
       }
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "setLabels.res",
-            691,
-            20
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "setLabels.res",
+          691,
+          20
+        ],
+        Error: new Error()
+      };
     };
     return sub(List.length(l), l)[0];
   };
diff --git a/lib/es6/sort.js b/lib/es6/sort.js
index 98d609d6e5..cc9d550760 100644
--- a/lib/es6/sort.js
+++ b/lib/es6/sort.js
@@ -114,12 +114,11 @@ function array(cmp, arr) {
       let i = lo + 1 | 0;
       let j = hi - 1 | 0;
       if (!cmp(pivot, arr[hi]) || !cmp(arr[lo], pivot)) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Sort.array"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Sort.array",
+          Error: new Error()
+        };
       }
       while (i < j) {
         while (!cmp(pivot, arr[i])) {
diff --git a/lib/es6/stack.js b/lib/es6/stack.js
index 147171622d..2ae12c6064 100644
--- a/lib/es6/stack.js
+++ b/lib/es6/stack.js
@@ -39,11 +39,10 @@ function pop(s) {
     s.len = s.len - 1 | 0;
     return match.hd;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function top(s) {
@@ -51,11 +50,10 @@ function top(s) {
   if (match) {
     return match.hd;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function is_empty(s) {
diff --git a/lib/es6/stream.js b/lib/es6/stream.js
index 2ed7fbfc14..6e0c953032 100644
--- a/lib/es6/stream.js
+++ b/lib/es6/stream.js
@@ -54,16 +54,15 @@ function get_data(count, _d) {
             }
           };
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "stream.res",
-              53,
-              13
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "stream.res",
+            53,
+            13
+          ],
+          Error: new Error()
+        };
       case "Slazy" :
         _d = CamlinternalLazy.force(d._0);
         continue;
@@ -116,16 +115,15 @@ function peek_data(s) {
           s.data = d;
           return Caml_option.some(d._0);
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "stream.res",
-              83,
-              13
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "stream.res",
+            83,
+            13
+          ],
+          Error: new Error()
+        };
       case "Slazy" :
         s.data = CamlinternalLazy.force(f._0);
         continue;
@@ -234,11 +232,10 @@ function next(s) {
     junk(s);
     return Caml_option.valFromOption(a);
   }
-  throw new Error(Failure, {
-    cause: {
-      RE_EXN_ID: Failure
-    }
-  });
+  throw {
+    RE_EXN_ID: Failure,
+    Error: new Error()
+  };
 }
 
 function empty(s) {
@@ -246,11 +243,10 @@ function empty(s) {
   if (match === undefined) {
     return;
   }
-  throw new Error(Failure, {
-    cause: {
-      RE_EXN_ID: Failure
-    }
-  });
+  throw {
+    RE_EXN_ID: Failure,
+    Error: new Error()
+  };
 }
 
 function iter(f, strm) {
diff --git a/lib/es6/string.js b/lib/es6/string.js
index 85e4d17c82..55e9b890cc 100644
--- a/lib/es6/string.js
+++ b/lib/es6/string.js
@@ -90,11 +90,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -129,12 +128,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -142,12 +140,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -156,11 +153,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -176,12 +172,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -206,12 +201,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -219,12 +213,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -234,9 +227,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -246,12 +237,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -261,9 +251,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/stringLabels.js b/lib/es6/stringLabels.js
index 72980fb1bb..789a8ff622 100644
--- a/lib/es6/stringLabels.js
+++ b/lib/es6/stringLabels.js
@@ -92,11 +92,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -131,12 +130,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -144,12 +142,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -158,11 +155,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -178,12 +174,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -208,12 +203,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -221,12 +215,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -236,9 +229,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -248,12 +239,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -263,9 +253,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/es6/uchar.js b/lib/es6/uchar.js
index c75c5caada..8ffb9e2054 100644
--- a/lib/es6/uchar.js
+++ b/lib/es6/uchar.js
@@ -16,12 +16,11 @@ function succ(u) {
     return 57344;
   }
   if (u === 1114111) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "U+10FFFF has no successor"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "U+10FFFF has no successor",
+      Error: new Error()
+    };
   }
   return u + 1 | 0;
 }
@@ -31,12 +30,11 @@ function pred(u) {
     return 55295;
   }
   if (u === 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "U+0000 has no predecessor"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "U+0000 has no predecessor",
+      Error: new Error()
+    };
   }
   return u - 1 | 0;
 }
@@ -56,12 +54,11 @@ function of_int(i) {
     return i;
   }
   let s = err_not_sv(i);
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function is_char(u) {
@@ -77,12 +74,11 @@ function to_char(u) {
     return u;
   }
   let s = err_not_latin1(u);
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function unsafe_to_char(prim) {
diff --git a/lib/js/arg.js b/lib/js/arg.js
index 89c4a76246..f606de0d6b 100644
--- a/lib/js/arg.js
+++ b/lib/js/arg.js
@@ -31,11 +31,10 @@ function assoc3(x, _l) {
       _l = l.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -57,15 +56,14 @@ function make_symlist(prefix, sep, suffix, l) {
 }
 
 function help_action() {
-  throw new Error(Stop, {
-    cause: {
-      RE_EXN_ID: Stop,
-      _1: {
-        TAG: "Unknown",
-        _0: "-help"
-      }
-    }
-  });
+  throw {
+    RE_EXN_ID: Stop,
+    _1: {
+      TAG: "Unknown",
+      _0: "-help"
+    },
+    Error: new Error()
+  };
 }
 
 function add_help(speclist) {
@@ -88,9 +86,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
   let add2;
@@ -112,9 +108,7 @@ function add_help(speclist) {
         tl: /* [] */0
       };
     } else {
-      throw new Error(exn$1.RE_EXN_ID, {
-        cause: exn$1
-      });
+      throw exn$1;
     }
   }
   return Pervasives.$at(speclist, Pervasives.$at(add1, add2));
@@ -159,9 +153,7 @@ function bool_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Invalid_argument") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -173,9 +165,7 @@ function int_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -187,9 +177,7 @@ function float_of_string_opt(x) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -261,24 +249,19 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
             } catch (raw_exn$1) {
               let exn$1 = Caml_js_exceptions.internalToOCamlException(raw_exn$1);
               if (exn$1.RE_EXN_ID === "Not_found") {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Unknown",
-                      _0: s
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Unknown",
+                    _0: s
+                  },
+                  Error: new Error()
+                };
               }
-              throw new Error(exn$1.RE_EXN_ID, {
-                cause: exn$1
-              });
+              throw exn$1;
             }
           } else {
-            throw new Error(exn.RE_EXN_ID, {
-              cause: exn
-            });
+            throw exn;
           }
         }
         let follow = match[1];
@@ -286,17 +269,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
           if (follow === undefined) {
             return;
           }
-          throw new Error(Stop, {
-            cause: {
-              RE_EXN_ID: Stop,
-              _1: {
-                TAG: "Wrong",
-                _0: s,
-                _1: follow,
-                _2: "no argument"
-              }
-            }
-          });
+          throw {
+            RE_EXN_ID: Stop,
+            _1: {
+              TAG: "Wrong",
+              _0: s,
+              _1: follow,
+              _2: "no argument"
+            },
+            Error: new Error()
+          };
         };
         let get_arg = () => {
           if (follow !== undefined) {
@@ -305,15 +287,14 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
           if ((current.contents + 1 | 0) < argv.contents.length) {
             return Caml_array.get(argv.contents, current.contents + 1 | 0);
           }
-          throw new Error(Stop, {
-            cause: {
-              RE_EXN_ID: Stop,
-              _1: {
-                TAG: "Missing",
-                _0: s
-              }
-            }
-          });
+          throw {
+            RE_EXN_ID: Stop,
+            _1: {
+              TAG: "Missing",
+              _0: s
+            },
+            Error: new Error()
+          };
         };
         let consume_arg = () => {
           if (follow !== undefined) {
@@ -333,17 +314,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (s$1 !== undefined) {
                 f._0(s$1);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg,
-                      _2: "a boolean"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg,
+                    _2: "a boolean"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set" :
@@ -367,17 +347,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x !== undefined) {
                 f._0(x);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$2,
-                      _2: "an integer"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$2,
+                    _2: "an integer"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set_int" :
@@ -386,17 +365,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$1 !== undefined) {
                 f._0.contents = x$1;
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$3,
-                      _2: "an integer"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$3,
+                    _2: "an integer"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Float" :
@@ -405,17 +383,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$2 !== undefined) {
                 f._0(x$2);
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$4,
-                      _2: "a float"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$4,
+                    _2: "a float"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Set_float" :
@@ -424,17 +401,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               if (x$3 !== undefined) {
                 f._0.contents = x$3;
               } else {
-                throw new Error(Stop, {
-                  cause: {
-                    RE_EXN_ID: Stop,
-                    _1: {
-                      TAG: "Wrong",
-                      _0: s,
-                      _1: arg$5,
-                      _2: "a float"
-                    }
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stop,
+                  _1: {
+                    TAG: "Wrong",
+                    _0: s,
+                    _1: arg$5,
+                    _2: "a float"
+                  },
+                  Error: new Error()
+                };
               }
               return consume_arg();
             case "Tuple" :
@@ -446,17 +422,16 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
                 f._1(arg$6);
                 return consume_arg();
               }
-              throw new Error(Stop, {
-                cause: {
-                  RE_EXN_ID: Stop,
-                  _1: {
-                    TAG: "Wrong",
-                    _0: s,
-                    _1: arg$6,
-                    _2: "one of: " + make_symlist("", " ", "", symb)
-                  }
-                }
-              });
+              throw {
+                RE_EXN_ID: Stop,
+                _1: {
+                  TAG: "Wrong",
+                  _0: s,
+                  _1: arg$6,
+                  _2: "one of: " + make_symlist("", " ", "", symb)
+                },
+                Error: new Error()
+              };
             case "Rest" :
               let f$1 = f._0;
               while (current.contents < (argv.contents.length - 1 | 0)) {
@@ -466,12 +441,11 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
               return;
             case "Expand" :
               if (!allow_expand) {
-                throw new Error("Invalid_argument", {
-                  cause: {
-                    RE_EXN_ID: "Invalid_argument",
-                    _1: "Arg.Expand is is only allowed with Arg.parse_and_expand_argv_dynamic"
-                  }
-                });
+                throw {
+                  RE_EXN_ID: "Invalid_argument",
+                  _1: "Arg.Expand is is only allowed with Arg.parse_and_expand_argv_dynamic",
+                  Error: new Error()
+                };
               }
               let arg$7 = get_arg();
               let newarg = f._0(arg$7);
@@ -498,24 +472,15 @@ function parse_and_expand_argv_dynamic_aux(allow_expand, current, argv, speclist
     } catch (raw_m) {
       let m = Caml_js_exceptions.internalToOCamlException(raw_m);
       if (m.RE_EXN_ID === Bad) {
-        throw new Error(convert_error({
+        throw convert_error({
           TAG: "Message",
           _0: m._1
-        }).RE_EXN_ID, {
-          cause: convert_error({
-            TAG: "Message",
-            _0: m._1
-          })
         });
       }
       if (m.RE_EXN_ID === Stop) {
-        throw new Error(convert_error(m._1).RE_EXN_ID, {
-          cause: convert_error(m._1)
-        });
+        throw convert_error(m._1);
       }
-      throw new Error(m.RE_EXN_ID, {
-        cause: m
-      });
+      throw m;
     }
     current.contents = current.contents + 1 | 0;
   };
@@ -552,9 +517,7 @@ function parse(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -571,9 +534,7 @@ function parse_dynamic(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -599,9 +560,7 @@ function parse_expand(l, f, msg) {
       console.log(msg$1._1);
       return Pervasives.exit(0);
     }
-    throw new Error(msg$1.RE_EXN_ID, {
-      cause: msg$1
-    });
+    throw msg$1;
   }
 }
 
@@ -636,18 +595,14 @@ function second_word(s) {
         if (exn$1.RE_EXN_ID === "Not_found") {
           return len;
         }
-        throw new Error(exn$1.RE_EXN_ID, {
-          cause: exn$1
-        });
+        throw exn$1;
       }
       if (exit === 2) {
         return loop(n$1 + 1 | 0);
       }
       
     } else {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   }
   return loop(n + 1 | 0);
diff --git a/lib/js/array.js b/lib/js/array.js
index 8bdf08b552..b262d5b67b 100644
--- a/lib/js/array.js
+++ b/lib/js/array.js
@@ -14,12 +14,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f(0));
   for (let i = 1; i < l; ++i) {
@@ -58,24 +57,22 @@ function append(a1, a2) {
 
 function sub(a, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.sub",
+      Error: new Error()
+    };
   }
   return Caml_array.sub(a, ofs, len);
 }
 
 function fill(a, ofs, len, v) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.fill",
+      Error: new Error()
+    };
   }
   for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
     a[i] = v;
@@ -84,12 +81,11 @@ function fill(a, ofs, len, v) {
 
 function blit(a1, ofs1, a2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.blit",
+      Error: new Error()
+    };
   }
   Caml_array.blit(a1, ofs1, a2, ofs2, len);
 }
@@ -102,12 +98,11 @@ function iter(f, a) {
 
 function iter2(f, a, b) {
   if (a.length !== b.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.iter2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.iter2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
     f(a[i], b[i]);
@@ -130,12 +125,11 @@ function map2(f, a, b) {
   let la = a.length;
   let lb = b.length;
   if (la !== lb) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.map2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.map2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   if (la === 0) {
     return [];
@@ -317,12 +311,11 @@ function sort(cmp, a) {
     if (i31 < l) {
       return i31;
     }
-    throw new Error(Bottom, {
-      cause: {
-        RE_EXN_ID: Bottom,
-        _1: i
-      }
-    });
+    throw {
+      RE_EXN_ID: Bottom,
+      _1: i,
+      Error: new Error()
+    };
   };
   let trickle = (l, i, e) => {
     try {
@@ -342,9 +335,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return Caml_array.set(a, i$2._1, e);
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let bubble = (l, i) => {
@@ -362,9 +353,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return i$2._1;
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let trickleup = (_i, e) => {
@@ -372,16 +361,15 @@ function sort(cmp, a) {
       let i = _i;
       let father = (i - 1 | 0) / 3 | 0;
       if (i === father) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "array.res",
-              321,
-              4
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "array.res",
+            321,
+            4
+          ],
+          Error: new Error()
+        };
       }
       if (cmp(Caml_array.get(a, father), e) >= 0) {
         return Caml_array.set(a, i, e);
diff --git a/lib/js/arrayLabels.js b/lib/js/arrayLabels.js
index cc4be0533e..bec5ae1c21 100644
--- a/lib/js/arrayLabels.js
+++ b/lib/js/arrayLabels.js
@@ -14,12 +14,11 @@ function init(l, f) {
     return [];
   }
   if (l < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.init",
+      Error: new Error()
+    };
   }
   let res = Caml_array.make(l, f(0));
   for (let i = 1; i < l; ++i) {
@@ -58,24 +57,22 @@ function append(a1, a2) {
 
 function sub(a, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.sub",
+      Error: new Error()
+    };
   }
   return Caml_array.sub(a, ofs, len);
 }
 
 function fill(a, ofs, len, v) {
   if (ofs < 0 || len < 0 || ofs > (a.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.fill",
+      Error: new Error()
+    };
   }
   for (let i = ofs, i_finish = ofs + len | 0; i < i_finish; ++i) {
     a[i] = v;
@@ -84,12 +81,11 @@ function fill(a, ofs, len, v) {
 
 function blit(a1, ofs1, a2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (a1.length - len | 0) || ofs2 < 0 || ofs2 > (a2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.blit",
+      Error: new Error()
+    };
   }
   Caml_array.blit(a1, ofs1, a2, ofs2, len);
 }
@@ -102,12 +98,11 @@ function iter(f, a) {
 
 function iter2(f, a, b) {
   if (a.length !== b.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.iter2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.iter2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   for (let i = 0, i_finish = a.length; i < i_finish; ++i) {
     f(a[i], b[i]);
@@ -130,12 +125,11 @@ function map2(f, a, b) {
   let la = a.length;
   let lb = b.length;
   if (la !== lb) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Array.map2: arrays must have the same length"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Array.map2: arrays must have the same length",
+      Error: new Error()
+    };
   }
   if (la === 0) {
     return [];
@@ -317,12 +311,11 @@ function sort(cmp, a) {
     if (i31 < l) {
       return i31;
     }
-    throw new Error(Bottom, {
-      cause: {
-        RE_EXN_ID: Bottom,
-        _1: i
-      }
-    });
+    throw {
+      RE_EXN_ID: Bottom,
+      _1: i,
+      Error: new Error()
+    };
   };
   let trickle = (l, i, e) => {
     try {
@@ -342,9 +335,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return Caml_array.set(a, i$2._1, e);
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let bubble = (l, i) => {
@@ -362,9 +353,7 @@ function sort(cmp, a) {
       if (i$2.RE_EXN_ID === Bottom) {
         return i$2._1;
       }
-      throw new Error(i$2.RE_EXN_ID, {
-        cause: i$2
-      });
+      throw i$2;
     }
   };
   let trickleup = (_i, e) => {
@@ -372,16 +361,15 @@ function sort(cmp, a) {
       let i = _i;
       let father = (i - 1 | 0) / 3 | 0;
       if (i === father) {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "arrayLabels.res",
-              321,
-              4
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "arrayLabels.res",
+            321,
+            4
+          ],
+          Error: new Error()
+        };
       }
       if (cmp(Caml_array.get(a, father), e) >= 0) {
         return Caml_array.set(a, i, e);
diff --git a/lib/js/belt_Array.js b/lib/js/belt_Array.js
index db7b6440a2..16962fb170 100644
--- a/lib/js/belt_Array.js
+++ b/lib/js/belt_Array.js
@@ -12,16 +12,15 @@ function get(arr, i) {
 
 function getExn(arr, i) {
   if (!(i >= 0 && i < arr.length)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "belt_Array.res",
-          36,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "belt_Array.res",
+        36,
+        2
+      ],
+      Error: new Error()
+    };
   }
   return arr[i];
 }
@@ -37,16 +36,15 @@ function set(arr, i, v) {
 
 function setExn(arr, i, v) {
   if (!(i >= 0 && i < arr.length)) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "belt_Array.res",
-          49,
-          2
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "belt_Array.res",
+        49,
+        2
+      ],
+      Error: new Error()
+    };
   }
   arr[i] = v;
 }
diff --git a/lib/js/belt_List.js b/lib/js/belt_List.js
index 0cbe6919bc..05e7f60db8 100644
--- a/lib/js/belt_List.js
+++ b/lib/js/belt_List.js
@@ -15,11 +15,10 @@ function headExn(x) {
   if (x) {
     return x.hd;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function tail(x) {
@@ -33,11 +32,10 @@ function tailExn(x) {
   if (x) {
     return x.tl;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function add(xs, x) {
@@ -71,11 +69,10 @@ function get(x, n) {
 
 function getExn(x, n) {
   if (n < 0) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let _x = x;
   let _n = n;
@@ -90,11 +87,10 @@ function getExn(x, n) {
       _x = x$1.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_MutableQueue.js b/lib/js/belt_MutableQueue.js
index 99bec2dd73..45ce2b1b62 100644
--- a/lib/js/belt_MutableQueue.js
+++ b/lib/js/belt_MutableQueue.js
@@ -54,11 +54,10 @@ function peekExn(q) {
   if (v !== undefined) {
     return v.content;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function pop(q) {
@@ -90,11 +89,10 @@ function popExn(q) {
       return x.content;
     }
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function popUndefined(q) {
diff --git a/lib/js/belt_Option.js b/lib/js/belt_Option.js
index cc15d6aeeb..c4f301c2b5 100644
--- a/lib/js/belt_Option.js
+++ b/lib/js/belt_Option.js
@@ -20,11 +20,10 @@ function getExn(x) {
   if (x !== undefined) {
     return Caml_option.valFromOption(x);
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function mapWithDefault(opt, $$default, f) {
diff --git a/lib/js/belt_Result.js b/lib/js/belt_Result.js
index accb607746..e221ef9d71 100644
--- a/lib/js/belt_Result.js
+++ b/lib/js/belt_Result.js
@@ -5,11 +5,10 @@ function getExn(x) {
   if (x.TAG === "Ok") {
     return x._0;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 function mapWithDefault(opt, $$default, f) {
diff --git a/lib/js/belt_internalAVLset.js b/lib/js/belt_internalAVLset.js
index bd0e013f01..3580ec8f6c 100644
--- a/lib/js/belt_internalAVLset.js
+++ b/lib/js/belt_internalAVLset.js
@@ -349,16 +349,15 @@ function checkInvariantInternal(_v) {
       r !== undefined ? r.h : 0
     ) | 0;
     if (!(diff <= 2 && diff >= -2)) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "belt_internalAVLset.res",
-            310,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "belt_internalAVLset.res",
+          310,
+          4
+        ],
+        Error: new Error()
+      };
     }
     checkInvariantInternal(l);
     _v = r;
@@ -700,11 +699,10 @@ function getExn(_n, x, cmp) {
       _n = c < 0 ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_internalAVLtree.js b/lib/js/belt_internalAVLtree.js
index 825157acc4..9fd0ebe1bf 100644
--- a/lib/js/belt_internalAVLtree.js
+++ b/lib/js/belt_internalAVLtree.js
@@ -546,16 +546,15 @@ function checkInvariantInternal(_v) {
     let r = v.r;
     let diff = treeHeight(l) - treeHeight(r) | 0;
     if (!(diff <= 2 && diff >= -2)) {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "belt_internalAVLtree.res",
-            439,
-            4
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "belt_internalAVLtree.res",
+          439,
+          4
+        ],
+        Error: new Error()
+      };
     }
     checkInvariantInternal(l);
     _v = r;
@@ -849,11 +848,10 @@ function getExn(_n, x, cmp) {
       _n = c < 0 ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_internalMapInt.js b/lib/js/belt_internalMapInt.js
index 033567d0f4..969acf741e 100644
--- a/lib/js/belt_internalMapInt.js
+++ b/lib/js/belt_internalMapInt.js
@@ -62,11 +62,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_internalMapString.js b/lib/js/belt_internalMapString.js
index 0db017ec4e..a371514a69 100644
--- a/lib/js/belt_internalMapString.js
+++ b/lib/js/belt_internalMapString.js
@@ -62,11 +62,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_internalSetInt.js b/lib/js/belt_internalSetInt.js
index d319345d87..211b1cd049 100644
--- a/lib/js/belt_internalSetInt.js
+++ b/lib/js/belt_internalSetInt.js
@@ -141,11 +141,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/belt_internalSetString.js b/lib/js/belt_internalSetString.js
index de811887c7..d591e8b41e 100644
--- a/lib/js/belt_internalSetString.js
+++ b/lib/js/belt_internalSetString.js
@@ -141,11 +141,10 @@ function getExn(_n, x) {
       _n = x < v ? n.l : n.r;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/buffer.js b/lib/js/buffer.js
index c59f4ffe76..6eedc8ab79 100644
--- a/lib/js/buffer.js
+++ b/lib/js/buffer.js
@@ -26,36 +26,33 @@ function to_bytes(b) {
 
 function sub(b, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (b.position - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.sub",
+      Error: new Error()
+    };
   }
   return Bytes.sub_string(b.buffer, ofs, len);
 }
 
 function blit(src, srcoff, dst, dstoff, len) {
   if (len < 0 || srcoff < 0 || srcoff > (src.position - len | 0) || dstoff < 0 || dstoff > (dst.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.blit",
+      Error: new Error()
+    };
   }
   Bytes.blit(src.buffer, srcoff, dst, dstoff, len);
 }
 
 function nth(b, ofs) {
   if (ofs < 0 || ofs >= b.position) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.nth",
+      Error: new Error()
+    };
   }
   return b.buffer[ofs];
 }
@@ -98,16 +95,15 @@ function add_char(b, c) {
 function add_utf_8_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          98,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        98,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 127) {
     return add_char(b, u$1);
@@ -145,31 +141,29 @@ function add_utf_8_uchar(b, u) {
     b.position = pos$2 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        127,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      127,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_utf_16be_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          132,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        132,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 65535) {
     let pos = b.position;
@@ -196,31 +190,29 @@ function add_utf_16be_uchar(b, u) {
     b.position = pos$1 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        154,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      154,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_utf_16le_uchar(b, u) {
   let u$1 = u;
   if (u$1 < 0) {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "buffer.res",
-          159,
-          18
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "buffer.res",
+        159,
+        18
+      ],
+      Error: new Error()
+    };
   }
   if (u$1 <= 65535) {
     let pos = b.position;
@@ -247,26 +239,24 @@ function add_utf_16le_uchar(b, u) {
     b.position = pos$1 + 4 | 0;
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        181,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      181,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function add_substring(b, s, offset, len) {
   if (offset < 0 || len < 0 || offset > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.add_substring/add_subbytes"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.add_substring/add_subbytes",
+      Error: new Error()
+    };
   }
   let new_position = b.position + len | 0;
   if (new_position > b.length) {
@@ -305,16 +295,15 @@ function closing(param) {
   if (param === 123) {
     return /* '}' */125;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "buffer.res",
-        216,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "buffer.res",
+      216,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 function advance_to_closing(opening, closing, k, s, start) {
@@ -325,11 +314,10 @@ function advance_to_closing(opening, closing, k, s, start) {
     let i = _i;
     let k$1 = _k;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (Caml_string.get(s, i) === opening) {
       _i = i + 1 | 0;
@@ -383,11 +371,10 @@ function advance_to_non_alpha(s, start) {
 
 function find_ident(s, start, lim) {
   if (start >= lim) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let c = Caml_string.get(s, start);
   if (c !== 40 && c !== 123) {
@@ -455,12 +442,11 @@ function add_substitute(b, f, s) {
 
 function truncate(b, len) {
   if (len < 0 || len > b.position) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Buffer.truncate"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Buffer.truncate",
+      Error: new Error()
+    };
   }
   b.position = len;
 }
diff --git a/lib/js/bytes.js b/lib/js/bytes.js
index b404268df9..13d10fe842 100644
--- a/lib/js/bytes.js
+++ b/lib/js/bytes.js
@@ -110,12 +110,11 @@ function of_string(s) {
 
 function sub(s, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.sub / Bytes.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.sub / Bytes.sub",
+      Error: new Error()
+    };
   }
   let r = Caml_bytes.create(len);
   unsafe_blit(s, ofs, r, 0, len);
@@ -138,23 +137,21 @@ function $plus$plus(a, b) {
     if (match$2) {
       return c;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   if (match$1) {
     return c;
   }
   if (match$2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   return c;
 }
@@ -180,36 +177,33 @@ function extend(s, left, right) {
 
 function fill(s, ofs, len, c) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.fill / Bytes.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.fill / Bytes.fill",
+      Error: new Error()
+    };
   }
   unsafe_fill(s, ofs, len, c);
 }
 
 function blit(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.blit",
+      Error: new Error()
+    };
   }
   unsafe_blit(s1, ofs1, s2, ofs2, len);
 }
 
 function blit_string(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.blit / Bytes.blit_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.blit / Bytes.blit_string",
+      Error: new Error()
+    };
   }
   if (len <= 0) {
     return;
@@ -245,12 +239,11 @@ function ensure_ge(x, y) {
   if (x >= y) {
     return x;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Bytes.concat"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Bytes.concat",
+    Error: new Error()
+  };
 }
 
 function sum_lengths(_acc, seplen, _param) {
@@ -489,11 +482,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -528,12 +520,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -541,12 +532,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -555,11 +545,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -575,12 +564,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -605,12 +593,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -618,12 +605,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -633,9 +619,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -645,12 +629,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -660,9 +643,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/bytesLabels.js b/lib/js/bytesLabels.js
index b404268df9..13d10fe842 100644
--- a/lib/js/bytesLabels.js
+++ b/lib/js/bytesLabels.js
@@ -110,12 +110,11 @@ function of_string(s) {
 
 function sub(s, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.sub / Bytes.sub"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.sub / Bytes.sub",
+      Error: new Error()
+    };
   }
   let r = Caml_bytes.create(len);
   unsafe_blit(s, ofs, r, 0, len);
@@ -138,23 +137,21 @@ function $plus$plus(a, b) {
     if (match$2) {
       return c;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   if (match$1) {
     return c;
   }
   if (match$2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.extend"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.extend",
+      Error: new Error()
+    };
   }
   return c;
 }
@@ -180,36 +177,33 @@ function extend(s, left, right) {
 
 function fill(s, ofs, len, c) {
   if (ofs < 0 || len < 0 || ofs > (s.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.fill / Bytes.fill"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.fill / Bytes.fill",
+      Error: new Error()
+    };
   }
   unsafe_fill(s, ofs, len, c);
 }
 
 function blit(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Bytes.blit"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Bytes.blit",
+      Error: new Error()
+    };
   }
   unsafe_blit(s1, ofs1, s2, ofs2, len);
 }
 
 function blit_string(s1, ofs1, s2, ofs2, len) {
   if (len < 0 || ofs1 < 0 || ofs1 > (s1.length - len | 0) || ofs2 < 0 || ofs2 > (s2.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.blit / Bytes.blit_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.blit / Bytes.blit_string",
+      Error: new Error()
+    };
   }
   if (len <= 0) {
     return;
@@ -245,12 +239,11 @@ function ensure_ge(x, y) {
   if (x >= y) {
     return x;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "Bytes.concat"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "Bytes.concat",
+    Error: new Error()
+  };
 }
 
 function sum_lengths(_acc, seplen, _param) {
@@ -489,11 +482,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -528,12 +520,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -541,12 +532,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -555,11 +545,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s[i] === c) {
       return i;
@@ -575,12 +564,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -605,12 +593,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -618,12 +605,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -633,9 +619,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -645,12 +629,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -660,9 +643,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/caml_array.js b/lib/js/caml_array.js
index 64193ae514..b04e555508 100644
--- a/lib/js/caml_array.js
+++ b/lib/js/caml_array.js
@@ -57,24 +57,22 @@ function concat(l) {
 
 function set(xs, index, newval) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   xs[index] = newval;
 }
 
 function get(xs, index) {
   if (index < 0 || index >= xs.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return xs[index];
 }
diff --git a/lib/js/caml_bigint.js b/lib/js/caml_bigint.js
index 30cda2d9ce..b6031d5ed0 100644
--- a/lib/js/caml_bigint.js
+++ b/lib/js/caml_bigint.js
@@ -3,22 +3,20 @@
 
 function div(x, y) {
   if (y === 0n) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x / y;
 }
 
 function mod_(x, y) {
   if (y === 0n) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x % y;
 }
diff --git a/lib/js/caml_bytes.js b/lib/js/caml_bytes.js
index b7909d1b9d..cc6553105a 100644
--- a/lib/js/caml_bytes.js
+++ b/lib/js/caml_bytes.js
@@ -3,36 +3,33 @@
 
 function set(s, i, ch) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   s[i] = ch;
 }
 
 function get(s, i) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return s[i];
 }
 
 function create(len) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.create"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.create",
+      Error: new Error()
+    };
   }
   let result = new Array(len);
   for (let i = 0; i < len; ++i) {
diff --git a/lib/js/caml_format.js b/lib/js/caml_format.js
index 7ec916dc57..e663e5d2fd 100644
--- a/lib/js/caml_format.js
+++ b/lib/js/caml_format.js
@@ -129,12 +129,11 @@ function int_of_string(s) {
   let c = i < len ? s.codePointAt(i) : /* '\000' */0;
   let d = parse_digit(c);
   if (d < 0 || d >= base) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int_of_string",
+      Error: new Error()
+    };
   }
   let aux = (_acc, _k) => {
     while (true) {
@@ -150,21 +149,19 @@ function int_of_string(s) {
       }
       let v = parse_digit(a);
       if (v < 0 || v >= base) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int_of_string",
+          Error: new Error()
+        };
       }
       let acc$1 = base * acc + v;
       if (acc$1 > threshold) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int_of_string",
+          Error: new Error()
+        };
       }
       _k = k + 1 | 0;
       _acc = acc$1;
@@ -174,12 +171,11 @@ function int_of_string(s) {
   let res = match[1] * aux(d, i + 1 | 0);
   let or_res = res | 0;
   if (base === 10 && res !== or_res) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int_of_string",
+      Error: new Error()
+    };
   }
   return or_res;
 }
@@ -218,12 +214,11 @@ function int64_of_string(s) {
   let c = i < len ? s.codePointAt(i) : /* '\000' */0;
   let d = Caml_int64.of_int32(parse_digit(c));
   if (Caml.i64_lt(d, Caml_int64.zero) || Caml.i64_ge(d, base)) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int64_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int64_of_string",
+      Error: new Error()
+    };
   }
   let aux = (_acc, _k) => {
     while (true) {
@@ -239,12 +234,11 @@ function int64_of_string(s) {
       }
       let v = Caml_int64.of_int32(parse_digit(a));
       if (Caml.i64_lt(v, Caml_int64.zero) || Caml.i64_ge(v, base) || Caml.i64_gt(acc, threshold)) {
-        throw new Error("Failure", {
-          cause: {
-            RE_EXN_ID: "Failure",
-            _1: "int64_of_string"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Failure",
+          _1: "int64_of_string",
+          Error: new Error()
+        };
       }
       let acc$1 = Caml_int64.add(Caml_int64.mul(base, acc), v);
       _k = k + 1 | 0;
@@ -258,12 +252,11 @@ function int64_of_string(s) {
       0,
       10
     ]) && Caml.i64_neq(res, or_res)) {
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "int64_of_string"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "int64_of_string",
+      Error: new Error()
+    };
   }
   return or_res;
 }
@@ -290,12 +283,11 @@ function lowercase(c) {
 function parse_format(fmt) {
   let len = fmt.length;
   if (len > 31) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "format_int: format too long"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "format_int: format too long",
+      Error: new Error()
+    };
   }
   let f = {
     justify: "+",
@@ -773,7 +765,7 @@ let float_of_string = (function(s,exn){
         return Infinity;
     if (/^-inf(inity)?$/i.test(s))
         return -Infinity;
-    throw new Error(exn.RE_EXN_ID, { cause: exn });;
+    throw exn;
 });
 
 function float_of_string$1(s) {
diff --git a/lib/js/caml_int32.js b/lib/js/caml_int32.js
index 8bb64e9cba..348de87617 100644
--- a/lib/js/caml_int32.js
+++ b/lib/js/caml_int32.js
@@ -3,22 +3,20 @@
 
 function div(x, y) {
   if (y === 0) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x / y | 0;
 }
 
 function mod_(x, y) {
   if (y === 0) {
-    throw new Error("Division_by_zero", {
-      cause: {
-        RE_EXN_ID: "Division_by_zero"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Division_by_zero",
+      Error: new Error()
+    };
   }
   return x % y;
 }
diff --git a/lib/js/caml_int64.js b/lib/js/caml_int64.js
index dcb3f8e08c..e83b0b310d 100644
--- a/lib/js/caml_int64.js
+++ b/lib/js/caml_int64.js
@@ -383,11 +383,10 @@ function div(_self, _other) {
     if (other[0] !== 0 || other[1] !== 0) {
       exit$1 = 2;
     } else {
-      throw new Error("Division_by_zero", {
-        cause: {
-          RE_EXN_ID: "Division_by_zero"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Division_by_zero",
+        Error: new Error()
+      };
     }
     if (exit$1 === 2) {
       if (self_hi !== -2147483648) {
diff --git a/lib/js/caml_js_exceptions.js b/lib/js/caml_js_exceptions.js
index 9fe06d0ffa..6d49e5228a 100644
--- a/lib/js/caml_js_exceptions.js
+++ b/lib/js/caml_js_exceptions.js
@@ -6,8 +6,8 @@ let Caml_exceptions = require("./caml_exceptions.js");
 let $$Error = "JsError";
 
 function internalToOCamlException(e) {
-  if (Caml_exceptions.is_extension(e.cause)) {
-    return e.cause;
+  if (Caml_exceptions.is_extension(e)) {
+    return e;
   } else {
     return {
       RE_EXN_ID: "JsError",
diff --git a/lib/js/caml_lexer.js b/lib/js/caml_lexer.js
index dfaf1adaca..1a5be6d097 100644
--- a/lib/js/caml_lexer.js
+++ b/lib/js/caml_lexer.js
@@ -87,7 +87,7 @@ let caml_lex_engine_aux = (function (tbl, start_state, lexbuf, exn){
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn })
+                throw exn
             else
                 return lexbuf.lex_last_action;
         }
@@ -222,7 +222,7 @@ let caml_new_lex_engine_aux = (function (tbl, start_state, lexbuf, exn) {
         if (state < 0) {
             lexbuf.lex_curr_pos = lexbuf.lex_last_pos;
             if (lexbuf.lex_last_action == -1)
-                throw new Error(exn.RE_EXN_ID, { cause: exn });
+                throw exn;
             else
                 return lexbuf.lex_last_action;
         }
diff --git a/lib/js/caml_module.js b/lib/js/caml_module.js
index b601cf66dd..f7caf02d8f 100644
--- a/lib/js/caml_module.js
+++ b/lib/js/caml_module.js
@@ -4,12 +4,11 @@ let Caml_obj = require("./caml_obj.js");
 
 function init_mod(loc, shape) {
   let undef_module = param => {
-    throw new Error("Undefined_recursive_module", {
-      cause: {
-        RE_EXN_ID: "Undefined_recursive_module",
-        _1: loc
-      }
-    });
+    throw {
+      RE_EXN_ID: "Undefined_recursive_module",
+      _1: loc,
+      Error: new Error()
+    };
   };
   let loop = (shape, struct_, idx) => {
     if (typeof shape !== "object") {
@@ -74,16 +73,15 @@ function update_mod(shape, o, n) {
     }
   };
   if (typeof shape !== "object") {
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "caml_module.res",
-          109,
-          9
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "caml_module.res",
+        109,
+        9
+      ],
+      Error: new Error()
+    };
   }
   if (shape.TAG === "Module") {
     let comps = shape._0;
@@ -94,16 +92,15 @@ function update_mod(shape, o, n) {
     }
     return;
   }
-  throw new Error("Assert_failure", {
-    cause: {
-      RE_EXN_ID: "Assert_failure",
-      _1: [
-        "caml_module.res",
-        109,
-        9
-      ]
-    }
-  });
+  throw {
+    RE_EXN_ID: "Assert_failure",
+    _1: [
+      "caml_module.res",
+      109,
+      9
+    ],
+    Error: new Error()
+  };
 }
 
 exports.init_mod = init_mod;
diff --git a/lib/js/caml_obj.js b/lib/js/caml_obj.js
index 0b3f182a11..edfcef1be3 100644
--- a/lib/js/caml_obj.js
+++ b/lib/js/caml_obj.js
@@ -55,12 +55,11 @@ function compare(a, b) {
       break;
     case "function" :
       if (b_type === "function") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "compare: functional value"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "compare: functional value",
+          Error: new Error()
+        };
       }
       break;
     case "number" :
@@ -136,12 +135,11 @@ function compare(a, b) {
         return Caml.int_compare(a[1], b[1]);
       }
       if (tag_a === 251) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "equal: abstract value"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "equal: abstract value",
+          Error: new Error()
+        };
       }
       if (tag_a !== tag_b) {
         if (tag_a < tag_b) {
@@ -262,12 +260,11 @@ function equal(a, b) {
   }
   let b_type = typeof b;
   if (a_type === "function" || b_type === "function") {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "equal: functional value"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "equal: functional value",
+      Error: new Error()
+    };
   }
   if (b_type === "number" || b_type === "bigint" || b_type === "undefined" || b === null) {
     return false;
@@ -278,12 +275,11 @@ function equal(a, b) {
     return a[1] === b[1];
   }
   if (tag_a === 251) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "equal: abstract value"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "equal: abstract value",
+      Error: new Error()
+    };
   }
   if (tag_a !== tag_b) {
     return false;
diff --git a/lib/js/caml_string.js b/lib/js/caml_string.js
index 252ba1b3fd..4ddd60890b 100644
--- a/lib/js/caml_string.js
+++ b/lib/js/caml_string.js
@@ -3,12 +3,11 @@
 
 function get(s, i) {
   if (i >= s.length || i < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "index out of bounds"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "index out of bounds",
+      Error: new Error()
+    };
   }
   return s.codePointAt(i);
 }
diff --git a/lib/js/caml_sys.js b/lib/js/caml_sys.js
index dae731f2ab..d2b6072de6 100644
--- a/lib/js/caml_sys.js
+++ b/lib/js/caml_sys.js
@@ -3,21 +3,19 @@
 
 function sys_getenv(s) {
   if (typeof process === "undefined" || process.env === undefined) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let x = process.env[s];
   if (x !== undefined) {
     return x;
   }
-  throw new Error("Not_found", {
-    cause: {
-      RE_EXN_ID: "Not_found"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Not_found",
+    Error: new Error()
+  };
 }
 
 let os_type = (function(_){
@@ -73,21 +71,19 @@ function sys_exit(exit_code) {
 }
 
 function sys_is_directory(_s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "sys_is_directory not implemented"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "sys_is_directory not implemented",
+    Error: new Error()
+  };
 }
 
 function sys_file_exists(_s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "sys_file_exists not implemented"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "sys_file_exists not implemented",
+    Error: new Error()
+  };
 }
 
 exports.sys_getenv = sys_getenv;
diff --git a/lib/js/camlinternalLazy.js b/lib/js/camlinternalLazy.js
index b92f4ac145..bf09987627 100644
--- a/lib/js/camlinternalLazy.js
+++ b/lib/js/camlinternalLazy.js
@@ -16,11 +16,10 @@ function forward_with_closure(blk, closure) {
 }
 
 function raise_undefined() {
-  throw new Error(Undefined, {
-    cause: {
-      RE_EXN_ID: Undefined
-    }
-  });
+  throw {
+    RE_EXN_ID: Undefined,
+    Error: new Error()
+  };
 }
 
 function force(lzv) {
@@ -33,13 +32,9 @@ function force(lzv) {
       return forward_with_closure(lzv, closure);
     } catch (e) {
       lzv.VAL = () => {
-        throw new Error(e.RE_EXN_ID, {
-          cause: e
-        });
+        throw e;
       };
-      throw new Error(e.RE_EXN_ID, {
-        cause: e
-      });
+      throw e;
     }
   }
 }
diff --git a/lib/js/char.js b/lib/js/char.js
index 319b877a5b..7a4984f70b 100644
--- a/lib/js/char.js
+++ b/lib/js/char.js
@@ -4,12 +4,11 @@ let Bytes = require("./bytes.js");
 
 function chr(n) {
   if (n < 0 || n > 255) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Char.chr"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Char.chr",
+      Error: new Error()
+    };
   }
   return n;
 }
diff --git a/lib/js/digest.js b/lib/js/digest.js
index 1630c5a8a8..5bd173cfda 100644
--- a/lib/js/digest.js
+++ b/lib/js/digest.js
@@ -17,12 +17,11 @@ function bytes(b) {
 
 function substring(str, ofs, len) {
   if (ofs < 0 || len < 0 || ofs > (str.length - len | 0)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.substring"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.substring",
+      Error: new Error()
+    };
   }
   return Caml_md5.md5_string(str, ofs, len);
 }
@@ -39,12 +38,11 @@ function char_hex(n) {
 
 function to_hex(d) {
   if (d.length !== 16) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.to_hex"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.to_hex",
+      Error: new Error()
+    };
   }
   let result = Caml_bytes.create(32);
   for (let i = 0; i <= 15; ++i) {
@@ -57,43 +55,39 @@ function to_hex(d) {
 
 function from_hex(s) {
   if (s.length !== 32) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Digest.from_hex"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Digest.from_hex",
+      Error: new Error()
+    };
   }
   let digit = c => {
     if (c >= 65) {
       if (c >= 97) {
         if (c >= 103) {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Digest.from_hex"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Digest.from_hex",
+            Error: new Error()
+          };
         }
         return (c - /* 'a' */97 | 0) + 10 | 0;
       }
       if (c >= 71) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Digest.from_hex"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Digest.from_hex",
+          Error: new Error()
+        };
       }
       return (c - /* 'A' */65 | 0) + 10 | 0;
     }
     if (c > 57 || c < 48) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Digest.from_hex"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Digest.from_hex",
+        Error: new Error()
+      };
     }
     return c - /* '0' */48 | 0;
   };
diff --git a/lib/js/filename.js b/lib/js/filename.js
index 293fb0b731..468cfb2c0f 100644
--- a/lib/js/filename.js
+++ b/lib/js/filename.js
@@ -123,9 +123,7 @@ try {
   if (exn.RE_EXN_ID === "Not_found") {
     temp_dir_name = "/tmp";
   } else {
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -205,9 +203,7 @@ try {
   if (exn$1.RE_EXN_ID === "Not_found") {
     temp_dir_name$1 = ".";
   } else {
-    throw new Error(exn$1.RE_EXN_ID, {
-      cause: exn$1
-    });
+    throw exn$1;
   }
 }
 
@@ -382,12 +378,11 @@ function concat(dirname, filename) {
 function chop_suffix(name, suff) {
   let n = name.length - suff.length | 0;
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Filename.chop_suffix"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Filename.chop_suffix",
+      Error: new Error()
+    };
   }
   return $$String.sub(name, 0, n);
 }
@@ -430,12 +425,11 @@ function extension(name) {
 function chop_extension(name) {
   let l = extension_len(name);
   if (l === 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Filename.chop_extension"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Filename.chop_extension",
+      Error: new Error()
+    };
   }
   return $$String.sub(name, 0, name.length - l | 0);
 }
diff --git a/lib/js/genlex.js b/lib/js/genlex.js
index 0b989249f2..658e6da2a3 100644
--- a/lib/js/genlex.js
+++ b/lib/js/genlex.js
@@ -58,9 +58,7 @@ function make_lexer(keywords) {
           _0: id
         };
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   let keyword_or_error = c => {
@@ -70,16 +68,13 @@ function make_lexer(keywords) {
     } catch (raw_exn) {
       let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
       if (exn.RE_EXN_ID === "Not_found") {
-        throw new Error(Stream.$$Error, {
-          cause: {
-            RE_EXN_ID: Stream.$$Error,
-            _1: "Illegal character " + s
-          }
-        });
+        throw {
+          RE_EXN_ID: Stream.$$Error,
+          _1: "Illegal character " + s,
+          Error: new Error()
+        };
       }
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
   };
   let next_token = strm__ => {
@@ -118,26 +113,22 @@ function make_lexer(keywords) {
                 } catch (raw_exn) {
                   let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
                   if (exn.RE_EXN_ID === Stream.Failure) {
-                    throw new Error(Stream.$$Error, {
-                      cause: {
-                        RE_EXN_ID: Stream.$$Error,
-                        _1: ""
-                      }
-                    });
+                    throw {
+                      RE_EXN_ID: Stream.$$Error,
+                      _1: "",
+                      Error: new Error()
+                    };
                   }
-                  throw new Error(exn.RE_EXN_ID, {
-                    cause: exn
-                  });
+                  throw exn;
                 }
                 let match = Stream.peek(strm__);
                 if (match !== undefined) {
                   if (match !== 39) {
-                    throw new Error(Stream.$$Error, {
-                      cause: {
-                        RE_EXN_ID: Stream.$$Error,
-                        _1: ""
-                      }
-                    });
+                    throw {
+                      RE_EXN_ID: Stream.$$Error,
+                      _1: "",
+                      Error: new Error()
+                    };
                   }
                   Stream.junk(strm__);
                   return {
@@ -145,12 +136,11 @@ function make_lexer(keywords) {
                     _0: c$1
                   };
                 }
-                throw new Error(Stream.$$Error, {
-                  cause: {
-                    RE_EXN_ID: Stream.$$Error,
-                    _1: ""
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stream.$$Error,
+                  _1: "",
+                  Error: new Error()
+                };
               case 40 :
                 Stream.junk(strm__);
                 let match$1 = Stream.peek(strm__);
@@ -473,16 +463,13 @@ function make_lexer(keywords) {
           } catch (raw_exn) {
             let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
             if (exn.RE_EXN_ID === Stream.Failure) {
-              throw new Error(Stream.$$Error, {
-                cause: {
-                  RE_EXN_ID: Stream.$$Error,
-                  _1: ""
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.$$Error,
+                _1: "",
+                Error: new Error()
+              };
             }
-            throw new Error(exn.RE_EXN_ID, {
-              cause: exn
-            });
+            throw exn;
           }
           store(c$1);
           continue;
@@ -490,11 +477,10 @@ function make_lexer(keywords) {
         Stream.junk(strm__);
         return get_string();
       }
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     };
   };
   let char = strm__ => {
@@ -510,23 +496,19 @@ function make_lexer(keywords) {
       } catch (raw_exn) {
         let exn = Caml_js_exceptions.internalToOCamlException(raw_exn);
         if (exn.RE_EXN_ID === Stream.Failure) {
-          throw new Error(Stream.$$Error, {
-            cause: {
-              RE_EXN_ID: Stream.$$Error,
-              _1: ""
-            }
-          });
+          throw {
+            RE_EXN_ID: Stream.$$Error,
+            _1: "",
+            Error: new Error()
+          };
         }
-        throw new Error(exn.RE_EXN_ID, {
-          cause: exn
-        });
+        throw exn;
       }
     } else {
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     }
   };
   let escape = strm__ => {
@@ -553,50 +535,45 @@ function make_lexer(keywords) {
           let c2 = Stream.peek(strm__);
           if (c2 !== undefined) {
             if (c2 > 57 || c2 < 48) {
-              throw new Error(Stream.$$Error, {
-                cause: {
-                  RE_EXN_ID: Stream.$$Error,
-                  _1: ""
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.$$Error,
+                _1: "",
+                Error: new Error()
+              };
             }
             Stream.junk(strm__);
             let c3 = Stream.peek(strm__);
             if (c3 !== undefined) {
               if (c3 > 57 || c3 < 48) {
-                throw new Error(Stream.$$Error, {
-                  cause: {
-                    RE_EXN_ID: Stream.$$Error,
-                    _1: ""
-                  }
-                });
+                throw {
+                  RE_EXN_ID: Stream.$$Error,
+                  _1: "",
+                  Error: new Error()
+                };
               }
               Stream.junk(strm__);
               return Char.chr((Math.imul(c1 - 48 | 0, 100) + Math.imul(c2 - 48 | 0, 10) | 0) + (c3 - 48 | 0) | 0);
             }
-            throw new Error(Stream.$$Error, {
-              cause: {
-                RE_EXN_ID: Stream.$$Error,
-                _1: ""
-              }
-            });
-          }
-          throw new Error(Stream.$$Error, {
-            cause: {
+            throw {
               RE_EXN_ID: Stream.$$Error,
-              _1: ""
-            }
-          });
+              _1: "",
+              Error: new Error()
+            };
+          }
+          throw {
+            RE_EXN_ID: Stream.$$Error,
+            _1: "",
+            Error: new Error()
+          };
         }
         Stream.junk(strm__);
         return c1;
       }
     } else {
-      throw new Error(Stream.Failure, {
-        cause: {
-          RE_EXN_ID: Stream.Failure
-        }
-      });
+      throw {
+        RE_EXN_ID: Stream.Failure,
+        Error: new Error()
+      };
     }
   };
   let comment = strm__ => {
@@ -617,11 +594,10 @@ function make_lexer(keywords) {
                 return comment(strm__);
               }
             }
-            throw new Error(Stream.Failure, {
-              cause: {
-                RE_EXN_ID: Stream.Failure
-              }
-            });
+            throw {
+              RE_EXN_ID: Stream.Failure,
+              Error: new Error()
+            };
           case 42 :
             Stream.junk(strm__);
             while (true) {
@@ -638,22 +614,20 @@ function make_lexer(keywords) {
                 Stream.junk(strm__);
                 return;
               }
-              throw new Error(Stream.Failure, {
-                cause: {
-                  RE_EXN_ID: Stream.Failure
-                }
-              });
+              throw {
+                RE_EXN_ID: Stream.Failure,
+                Error: new Error()
+              };
             };
           default:
             Stream.junk(strm__);
             continue;
         }
       } else {
-        throw new Error(Stream.Failure, {
-          cause: {
-            RE_EXN_ID: Stream.Failure
-          }
-        });
+        throw {
+          RE_EXN_ID: Stream.Failure,
+          Error: new Error()
+        };
       }
     };
   };
diff --git a/lib/js/hashtbl.js b/lib/js/hashtbl.js
index b22fa9064a..2d2fe16921 100644
--- a/lib/js/hashtbl.js
+++ b/lib/js/hashtbl.js
@@ -109,16 +109,15 @@ function copy_bucketlist(param) {
         next: next
       };
       if (typeof prec !== "object") {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "hashtbl.res",
-              110,
-              19
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "hashtbl.res",
+            110,
+            19
+          ],
+          Error: new Error()
+        };
       }
       prec.next = r;
       _param = next;
@@ -252,11 +251,10 @@ function remove(h, key) {
 function find(h, key) {
   let match = Caml_array.get(h.data, key_index(h, key));
   if (typeof match !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k1 = match.key;
   let d1 = match.data;
@@ -265,11 +263,10 @@ function find(h, key) {
     return d1;
   }
   if (typeof next1 !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k2 = next1.key;
   let d2 = next1.data;
@@ -278,11 +275,10 @@ function find(h, key) {
     return d2;
   }
   if (typeof next2 !== "object") {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   let k3 = next2.key;
   let d3 = next2.data;
@@ -294,11 +290,10 @@ function find(h, key) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let k = param.key;
       let data = param.data;
@@ -468,14 +463,10 @@ function iter(f, h) {
     }
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -525,14 +516,10 @@ function filter_map_inplace(f, h) {
     return;
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -568,14 +555,10 @@ function fold(f, h, init) {
     return accu;
   } catch (exn) {
     if (old_trav) {
-      throw new Error(exn.RE_EXN_ID, {
-        cause: exn
-      });
+      throw exn;
     }
     flip_ongoing_traversal(h);
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -654,11 +637,10 @@ function MakeSeeded(H) {
   let find = (h, key) => {
     let match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k1 = match.key;
     let d1 = match.data;
@@ -667,11 +649,10 @@ function MakeSeeded(H) {
       return d1;
     }
     if (typeof next1 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k2 = next1.key;
     let d2 = next1.data;
@@ -680,11 +661,10 @@ function MakeSeeded(H) {
       return d2;
     }
     if (typeof next2 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k3 = next2.key;
     let d3 = next2.data;
@@ -696,11 +676,10 @@ function MakeSeeded(H) {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let k = param.key;
         let data = param.data;
@@ -900,11 +879,10 @@ function Make(H) {
   let find = (h, key) => {
     let match = Caml_array.get(h.data, key_index(h, key));
     if (typeof match !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k1 = match.key;
     let d1 = match.data;
@@ -913,11 +891,10 @@ function Make(H) {
       return d1;
     }
     if (typeof next1 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k2 = next1.key;
     let d2 = next1.data;
@@ -926,11 +903,10 @@ function Make(H) {
       return d2;
     }
     if (typeof next2 !== "object") {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     let k3 = next2.key;
     let d3 = next2.data;
@@ -942,11 +918,10 @@ function Make(H) {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let k = param.key;
         let data = param.data;
diff --git a/lib/js/int32.js b/lib/js/int32.js
index 00883d1909..2493b20d95 100644
--- a/lib/js/int32.js
+++ b/lib/js/int32.js
@@ -36,9 +36,7 @@ function of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/int64.js b/lib/js/int64.js
index b46cab5118..c6423d62e4 100644
--- a/lib/js/int64.js
+++ b/lib/js/int64.js
@@ -29,9 +29,7 @@ function of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/js_exn.js b/lib/js/js_exn.js
index 706c4b6181..34b90db044 100644
--- a/lib/js/js_exn.js
+++ b/lib/js/js_exn.js
@@ -2,45 +2,31 @@
 
 
 function raiseError(str) {
-  throw new Error(new Error(str).RE_EXN_ID, {
-    cause: new Error(str)
-  });
+  throw new Error(str);
 }
 
 function raiseEvalError(str) {
-  throw new Error(new EvalError(str).RE_EXN_ID, {
-    cause: new EvalError(str)
-  });
+  throw new EvalError(str);
 }
 
 function raiseRangeError(str) {
-  throw new Error(new RangeError(str).RE_EXN_ID, {
-    cause: new RangeError(str)
-  });
+  throw new RangeError(str);
 }
 
 function raiseReferenceError(str) {
-  throw new Error(new ReferenceError(str).RE_EXN_ID, {
-    cause: new ReferenceError(str)
-  });
+  throw new ReferenceError(str);
 }
 
 function raiseSyntaxError(str) {
-  throw new Error(new SyntaxError(str).RE_EXN_ID, {
-    cause: new SyntaxError(str)
-  });
+  throw new SyntaxError(str);
 }
 
 function raiseTypeError(str) {
-  throw new Error(new TypeError(str).RE_EXN_ID, {
-    cause: new TypeError(str)
-  });
+  throw new TypeError(str);
 }
 
 function raiseUriError(str) {
-  throw new Error(new URIError(str).RE_EXN_ID, {
-    cause: new URIError(str)
-  });
+  throw new URIError(str);
 }
 
 let $$Error$1 = "JsError";
diff --git a/lib/js/js_null.js b/lib/js/js_null.js
index 7d8ddcb6e1..682a2a31a5 100644
--- a/lib/js/js_null.js
+++ b/lib/js/js_null.js
@@ -10,9 +10,7 @@ function getExn(f) {
   if (f !== null) {
     return f;
   }
-  throw new Error(new Error("Js.Null.getExn").RE_EXN_ID, {
-    cause: new Error("Js.Null.getExn")
-  });
+  throw new Error("Js.Null.getExn");
 }
 
 function bind(x, f) {
diff --git a/lib/js/js_option.js b/lib/js/js_option.js
index 0b876c2b9a..5a513afd29 100644
--- a/lib/js/js_option.js
+++ b/lib/js/js_option.js
@@ -26,9 +26,7 @@ function getExn(x) {
   if (x !== undefined) {
     return Caml_option.valFromOption(x);
   }
-  throw new Error(new Error("getExn").RE_EXN_ID, {
-    cause: new Error("getExn")
-  });
+  throw new Error("getExn");
 }
 
 function equal(eq, a, b) {
diff --git a/lib/js/js_undefined.js b/lib/js/js_undefined.js
index 567ce8fec5..f67e1ec960 100644
--- a/lib/js/js_undefined.js
+++ b/lib/js/js_undefined.js
@@ -14,9 +14,7 @@ function getExn(f) {
   if (f !== undefined) {
     return f;
   }
-  throw new Error(new Error("Js.Undefined.getExn").RE_EXN_ID, {
-    cause: new Error("Js.Undefined.getExn")
-  });
+  throw new Error("Js.Undefined.getExn");
 }
 
 function bind(x, f) {
diff --git a/lib/js/lexing.js b/lib/js/lexing.js
index 8b7d2f0f20..01083fc59f 100644
--- a/lib/js/lexing.js
+++ b/lib/js/lexing.js
@@ -54,12 +54,11 @@ function from_function(f) {
         } else {
           let newlen = (x.lex_buffer.length << 1);
           if (((x.lex_buffer_len - x.lex_start_pos | 0) + n | 0) > newlen) {
-            throw new Error("Failure", {
-              cause: {
-                RE_EXN_ID: "Failure",
-                _1: "Lexing.lex_refill: cannot grow buffer"
-              }
-            });
+            throw {
+              RE_EXN_ID: "Failure",
+              _1: "Lexing.lex_refill: cannot grow buffer",
+              Error: new Error()
+            };
           }
           let newbuf = Caml_bytes.create(newlen);
           Bytes.blit(x.lex_buffer, x.lex_start_pos, newbuf, 0, x.lex_buffer_len - x.lex_start_pos | 0);
diff --git a/lib/js/list.js b/lib/js/list.js
index cebd113d2d..967d6dbb66 100644
--- a/lib/js/list.js
+++ b/lib/js/list.js
@@ -30,34 +30,31 @@ function hd(param) {
   if (param) {
     return param.hd;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "hd"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "hd",
+    Error: new Error()
+  };
 }
 
 function tl(param) {
   if (param) {
     return param.tl;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "tl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "tl",
+    Error: new Error()
+  };
 }
 
 function nth(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -72,23 +69,21 @@ function nth(l, n) {
       _l = l$1.tl;
       continue;
     }
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "nth",
+      Error: new Error()
+    };
   };
 }
 
 function nth_opt(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -156,12 +151,11 @@ function init_aux(i, n, f) {
 
 function init(len, f) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.init",
+      Error: new Error()
+    };
   }
   if (len > 10000) {
     return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
@@ -280,22 +274,20 @@ function map2(f, l1, l2) {
         tl: map2(f, l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2",
+    Error: new Error()
+  };
 }
 
 function rev_map2(f, l1, l2) {
@@ -316,20 +308,18 @@ function rev_map2(f, l1, l2) {
         };
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     if (l2$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -346,22 +336,20 @@ function iter2(f, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.iter2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.iter2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.iter2",
+      Error: new Error()
+    };
   };
 }
 
@@ -377,20 +365,18 @@ function fold_left2(f, _accu, _l1, _l2) {
         _accu = f(accu, l1.hd, l2.hd);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     if (l2) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -401,20 +387,18 @@ function fold_right2(f, l1, l2, accu) {
     if (l2) {
       return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -460,22 +444,20 @@ function for_all2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.for_all2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.for_all2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return true;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.for_all2",
+      Error: new Error()
+    };
   };
 }
 
@@ -492,22 +474,20 @@ function exists2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.exists2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.exists2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return false;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.exists2",
+      Error: new Error()
+    };
   };
 }
 
@@ -550,11 +530,10 @@ function assoc(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -584,11 +563,10 @@ function assq(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -678,11 +656,10 @@ function find(p, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -790,22 +767,20 @@ function combine(l1, l2) {
         tl: combine(l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.combine"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.combine",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.combine",
+    Error: new Error()
+  };
 }
 
 function merge(cmp, l1, l2) {
@@ -842,16 +817,15 @@ function chop(_k, _l) {
       _k = k - 1 | 0;
       continue;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "list.res",
-          420,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "list.res",
+        420,
+        11
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/listLabels.js b/lib/js/listLabels.js
index b026ab1ad4..efb24d4ab4 100644
--- a/lib/js/listLabels.js
+++ b/lib/js/listLabels.js
@@ -30,34 +30,31 @@ function hd(param) {
   if (param) {
     return param.hd;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "hd"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "hd",
+    Error: new Error()
+  };
 }
 
 function tl(param) {
   if (param) {
     return param.tl;
   }
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: "tl"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: "tl",
+    Error: new Error()
+  };
 }
 
 function nth(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -72,23 +69,21 @@ function nth(l, n) {
       _l = l$1.tl;
       continue;
     }
-    throw new Error("Failure", {
-      cause: {
-        RE_EXN_ID: "Failure",
-        _1: "nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Failure",
+      _1: "nth",
+      Error: new Error()
+    };
   };
 }
 
 function nth_opt(l, n) {
   if (n < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.nth"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.nth",
+      Error: new Error()
+    };
   }
   let _l = l;
   let _n = n;
@@ -156,12 +151,11 @@ function init_aux(i, n, f) {
 
 function init(len, f) {
   if (len < 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.init"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.init",
+      Error: new Error()
+    };
   }
   if (len > 10000) {
     return rev_append(init_tailrec_aux(/* [] */0, 0, len, f), /* [] */0);
@@ -280,22 +274,20 @@ function map2(f, l1, l2) {
         tl: map2(f, l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.map2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.map2",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.map2"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.map2",
+    Error: new Error()
+  };
 }
 
 function rev_map2(f, l1, l2) {
@@ -316,20 +308,18 @@ function rev_map2(f, l1, l2) {
         };
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     if (l2$1) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.rev_map2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.rev_map2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -346,22 +336,20 @@ function iter2(f, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.iter2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.iter2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.iter2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.iter2",
+      Error: new Error()
+    };
   };
 }
 
@@ -377,20 +365,18 @@ function fold_left2(f, _accu, _l1, _l2) {
         _accu = f(accu, l1.hd, l2.hd);
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     if (l2) {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.fold_left2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.fold_left2",
+        Error: new Error()
+      };
     }
     return accu;
   };
@@ -401,20 +387,18 @@ function fold_right2(f, l1, l2, accu) {
     if (l2) {
       return f(l1.hd, l2.hd, fold_right2(f, l1.tl, l2.tl, accu));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   if (l2) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.fold_right2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.fold_right2",
+      Error: new Error()
+    };
   }
   return accu;
 }
@@ -460,22 +444,20 @@ function for_all2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.for_all2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.for_all2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return true;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.for_all2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.for_all2",
+      Error: new Error()
+    };
   };
 }
 
@@ -492,22 +474,20 @@ function exists2(p, _l1, _l2) {
         _l1 = l1.tl;
         continue;
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "List.exists2"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "List.exists2",
+        Error: new Error()
+      };
     }
     if (!l2) {
       return false;
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.exists2"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.exists2",
+      Error: new Error()
+    };
   };
 }
 
@@ -550,11 +530,10 @@ function assoc(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -584,11 +563,10 @@ function assq(x, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -678,11 +656,10 @@ function find(p, _param) {
       _param = param.tl;
       continue;
     }
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   };
 }
 
@@ -790,22 +767,20 @@ function combine(l1, l2) {
         tl: combine(l1.tl, l2.tl)
       };
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "List.combine"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "List.combine",
+      Error: new Error()
+    };
   }
   if (!l2) {
     return /* [] */0;
   }
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: "List.combine"
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: "List.combine",
+    Error: new Error()
+  };
 }
 
 function merge(cmp, l1, l2) {
@@ -842,16 +817,15 @@ function chop(_k, _l) {
       _k = k - 1 | 0;
       continue;
     }
-    throw new Error("Assert_failure", {
-      cause: {
-        RE_EXN_ID: "Assert_failure",
-        _1: [
-          "listLabels.res",
-          420,
-          11
-        ]
-      }
-    });
+    throw {
+      RE_EXN_ID: "Assert_failure",
+      _1: [
+        "listLabels.res",
+        420,
+        11
+      ],
+      Error: new Error()
+    };
   };
 }
 
diff --git a/lib/js/map.js b/lib/js/map.js
index 3588ee0024..33fa37ef6e 100644
--- a/lib/js/map.js
+++ b/lib/js/map.js
@@ -37,12 +37,11 @@ function Make(funarg) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let ld = l.d;
@@ -54,12 +53,11 @@ function Make(funarg) {
       if (typeof lr === "object") {
         return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -72,12 +70,11 @@ function Make(funarg) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rd = r.d;
@@ -89,12 +86,11 @@ function Make(funarg) {
     if (typeof rl === "object") {
       return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   };
   let is_empty = param => {
     if (typeof param !== "object") {
@@ -152,11 +148,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = funarg.compare(x, param.v);
       if (c === 0) {
@@ -170,11 +165,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -246,11 +240,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -350,11 +343,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -388,11 +380,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -424,12 +415,11 @@ function Make(funarg) {
   };
   let remove_min_binding = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -717,16 +707,15 @@ function Make(funarg) {
       
     }
     if (typeof s2 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "map.res",
-            552,
-            11
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "map.res",
+          552,
+          11
+        ],
+        Error: new Error()
+      };
     }
     let v2 = s2.v;
     let match$1 = split(v2, s1);
diff --git a/lib/js/mapLabels.js b/lib/js/mapLabels.js
index 4094b6e60e..8b5b3c56fd 100644
--- a/lib/js/mapLabels.js
+++ b/lib/js/mapLabels.js
@@ -37,12 +37,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let ld = l.d;
@@ -54,12 +53,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -72,12 +70,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rd = r.d;
@@ -89,12 +86,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Map.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Map.bal",
+      Error: new Error()
+    };
   };
   let is_empty = param => {
     if (typeof param !== "object") {
@@ -152,11 +148,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let c = Ord.compare(x, param.v);
       if (c === 0) {
@@ -192,11 +187,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -268,11 +262,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -350,11 +343,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -388,11 +380,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -424,12 +415,11 @@ function Make(Ord) {
   };
   let remove_min_binding = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -717,16 +707,15 @@ function Make(Ord) {
       
     }
     if (typeof s2 !== "object") {
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "mapLabels.res",
-            552,
-            11
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "mapLabels.res",
+          552,
+          11
+        ],
+        Error: new Error()
+      };
     }
     let v2 = s2.v;
     let match$1 = split(v2, s1);
diff --git a/lib/js/moreLabels.js b/lib/js/moreLabels.js
index fdbe98c04b..1afa76adb7 100644
--- a/lib/js/moreLabels.js
+++ b/lib/js/moreLabels.js
@@ -67,12 +67,11 @@ let $$Map = {
       hr = typeof r !== "object" ? 0 : r.h;
       if (hl > (hr + 2 | 0)) {
         if (typeof l !== "object") {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Map.bal"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Map.bal",
+            Error: new Error()
+          };
         }
         let lr = l.r;
         let ld = l.d;
@@ -84,12 +83,11 @@ let $$Map = {
         if (typeof lr === "object") {
           return create(create(ll, lv, ld, lr.l), lr.v, lr.d, create(lr.r, x, d, r));
         }
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       if (hr <= (hl + 2 | 0)) {
         return {
@@ -102,12 +100,11 @@ let $$Map = {
         };
       }
       if (typeof r !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.bal",
+          Error: new Error()
+        };
       }
       let rr = r.r;
       let rd = r.d;
@@ -119,12 +116,11 @@ let $$Map = {
       if (typeof rl === "object") {
         return create(create(l, x, d, rl.l), rl.v, rl.d, create(rl.r, rv, rd, rr));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Map.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Map.bal",
+        Error: new Error()
+      };
     };
     let is_empty = param => {
       if (typeof param !== "object") {
@@ -182,11 +178,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let c = funarg.compare(x, param.v);
         if (c === 0) {
@@ -222,11 +217,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -298,11 +292,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -380,11 +373,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let l = param.l;
         if (typeof l !== "object") {
@@ -418,11 +410,10 @@ let $$Map = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let r = param.r;
         if (typeof r !== "object") {
@@ -454,12 +445,11 @@ let $$Map = {
     };
     let remove_min_binding = param => {
       if (typeof param !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Map.remove_min_elt"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Map.remove_min_elt",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -747,16 +737,15 @@ let $$Map = {
         
       }
       if (typeof s2 !== "object") {
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "mapLabels.res",
-              552,
-              11
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "mapLabels.res",
+            552,
+            11
+          ],
+          Error: new Error()
+        };
       }
       let v2 = s2.v;
       let match$1 = split(v2, s1);
@@ -1011,12 +1000,11 @@ let $$Set = {
       hr = typeof r !== "object" ? 0 : r.h;
       if (hl > (hr + 2 | 0)) {
         if (typeof l !== "object") {
-          throw new Error("Invalid_argument", {
-            cause: {
-              RE_EXN_ID: "Invalid_argument",
-              _1: "Set.bal"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Invalid_argument",
+            _1: "Set.bal",
+            Error: new Error()
+          };
         }
         let lr = l.r;
         let lv = l.v;
@@ -1027,12 +1015,11 @@ let $$Set = {
         if (typeof lr === "object") {
           return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
         }
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       if (hr <= (hl + 2 | 0)) {
         return {
@@ -1044,12 +1031,11 @@ let $$Set = {
         };
       }
       if (typeof r !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let rr = r.r;
       let rv = r.v;
@@ -1060,12 +1046,11 @@ let $$Set = {
       if (typeof rl === "object") {
         return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     };
     let add = (x, param) => {
       if (typeof param !== "object") {
@@ -1141,11 +1126,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let l = param.l;
         if (typeof l !== "object") {
@@ -1173,11 +1157,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let r = param.r;
         if (typeof r !== "object") {
@@ -1203,12 +1186,11 @@ let $$Set = {
     };
     let remove_min_elt = param => {
       if (typeof param !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.remove_min_elt"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.remove_min_elt",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -1598,11 +1580,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         let c = funarg.compare(x, v);
@@ -1634,11 +1615,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -1700,11 +1680,10 @@ let $$Set = {
       while (true) {
         let param = _param;
         if (typeof param !== "object") {
-          throw new Error("Not_found", {
-            cause: {
-              RE_EXN_ID: "Not_found"
-            }
-          });
+          throw {
+            RE_EXN_ID: "Not_found",
+            Error: new Error()
+          };
         }
         let v = param.v;
         if (f(v)) {
@@ -1874,16 +1853,15 @@ let $$Set = {
             match$4[1]
           ];
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "setLabels.res",
-              691,
-              20
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "setLabels.res",
+            691,
+            20
+          ],
+          Error: new Error()
+        };
       };
       return sub(List.length(l), l)[0];
     };
diff --git a/lib/js/parsing.js b/lib/js/parsing.js
index b4a3eef011..060a22154d 100644
--- a/lib/js/parsing.js
+++ b/lib/js/parsing.js
@@ -85,11 +85,10 @@ function yyparse(tables, start, lexer, lexbuf) {
           _cmd = "Token_read";
           continue;
         case "Raise_parse_error" :
-          throw new Error(Parse_error, {
-            cause: {
-              RE_EXN_ID: Parse_error
-            }
-          });
+          throw {
+            RE_EXN_ID: Parse_error,
+            Error: new Error()
+          };
         case "Grow_stacks_1" :
           grow_stacks();
           _arg = undefined;
@@ -115,9 +114,7 @@ function yyparse(tables, start, lexer, lexbuf) {
                 undefined
               ];
             } else {
-              throw new Error(exn.RE_EXN_ID, {
-                cause: exn
-              });
+              throw exn;
             }
           }
           _arg = match$1[1];
@@ -150,9 +147,7 @@ function yyparse(tables, start, lexer, lexbuf) {
         return Caml_array.get(tables.transl_const, tok) === curr_char;
       }
     };
-    throw new Error(exn$1.RE_EXN_ID, {
-      cause: exn$1
-    });
+    throw exn$1;
   }
 }
 
diff --git a/lib/js/pervasives.js b/lib/js/pervasives.js
index 445c238f4b..e565627692 100644
--- a/lib/js/pervasives.js
+++ b/lib/js/pervasives.js
@@ -7,21 +7,19 @@ let Caml_exceptions = require("./caml_exceptions.js");
 let Caml_js_exceptions = require("./caml_js_exceptions.js");
 
 function failwith(s) {
-  throw new Error("Failure", {
-    cause: {
-      RE_EXN_ID: "Failure",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Failure",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function invalid_arg(s) {
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 let Exit = /* @__PURE__ */Caml_exceptions.create("Pervasives.Exit");
@@ -58,12 +56,11 @@ function classify_float(x) {
 
 function char_of_int(n) {
   if (n < 0 || n > 255) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "char_of_int"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "char_of_int",
+      Error: new Error()
+    };
   }
   return n;
 }
@@ -83,12 +80,11 @@ function bool_of_string(param) {
     case "true" :
       return true;
     default:
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "bool_of_string"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "bool_of_string",
+        Error: new Error()
+      };
   }
 }
 
@@ -111,9 +107,7 @@ function int_of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -153,9 +147,7 @@ function float_of_string_opt(s) {
     if (exn.RE_EXN_ID === "Failure") {
       return;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/queue.js b/lib/js/queue.js
index eaf58a010c..a6a5df8fa2 100644
--- a/lib/js/queue.js
+++ b/lib/js/queue.js
@@ -41,21 +41,19 @@ function peek(q) {
   if (typeof match === "object") {
     return match.content;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function take(q) {
   let match = q.first;
   if (typeof match !== "object") {
-    throw new Error(Empty, {
-      cause: {
-        RE_EXN_ID: Empty
-      }
-    });
+    throw {
+      RE_EXN_ID: Empty,
+      Error: new Error()
+    };
   }
   let content = match.content;
   let next = match.next;
diff --git a/lib/js/random.js b/lib/js/random.js
index 0b844d4e69..5202c9f031 100644
--- a/lib/js/random.js
+++ b/lib/js/random.js
@@ -71,12 +71,11 @@ function bits(s) {
 
 function int(s, bound) {
   if (bound > 1073741823 || bound <= 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int",
+      Error: new Error()
+    };
   }
   while (true) {
     let r = bits(s);
@@ -90,12 +89,11 @@ function int(s, bound) {
 
 function int32(s, bound) {
   if (bound <= 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int32"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int32",
+      Error: new Error()
+    };
   }
   while (true) {
     let b1 = bits(s);
@@ -111,12 +109,11 @@ function int32(s, bound) {
 
 function int64(s, bound) {
   if (Caml.i64_le(bound, Caml_int64.zero)) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Random.int64"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Random.int64",
+      Error: new Error()
+    };
   }
   while (true) {
     let b1 = Caml_int64.of_int32(bits(s));
diff --git a/lib/js/runtime_deriving.js b/lib/js/runtime_deriving.js
index 5b1bc5652f..0f0f4175e3 100644
--- a/lib/js/runtime_deriving.js
+++ b/lib/js/runtime_deriving.js
@@ -3,11 +3,10 @@
 
 function raiseWhenNotFound(x) {
   if (x == null) {
-    throw new Error("Not_found", {
-      cause: {
-        RE_EXN_ID: "Not_found"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Not_found",
+      Error: new Error()
+    };
   }
   return x;
 }
diff --git a/lib/js/set.js b/lib/js/set.js
index 3b5ca118c9..38b2616ce9 100644
--- a/lib/js/set.js
+++ b/lib/js/set.js
@@ -31,12 +31,11 @@ function Make(funarg) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let lv = l.v;
@@ -47,12 +46,11 @@ function Make(funarg) {
       if (typeof lr === "object") {
         return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -64,12 +62,11 @@ function Make(funarg) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rv = r.v;
@@ -80,12 +77,11 @@ function Make(funarg) {
     if (typeof rl === "object") {
       return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   };
   let add = (x, param) => {
     if (typeof param !== "object") {
@@ -161,11 +157,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -193,11 +188,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -223,12 +217,11 @@ function Make(funarg) {
   };
   let remove_min_elt = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -616,11 +609,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       let c = funarg.compare(x, v);
@@ -635,11 +627,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -699,11 +690,10 @@ function Make(funarg) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -906,16 +896,15 @@ function Make(funarg) {
               match$4[1]
             ];
           }
-          throw new Error("Assert_failure", {
-            cause: {
-              RE_EXN_ID: "Assert_failure",
-              _1: [
-                "set.res",
-                691,
-                20
-              ]
-            }
-          });
+          throw {
+            RE_EXN_ID: "Assert_failure",
+            _1: [
+              "set.res",
+              691,
+              20
+            ],
+            Error: new Error()
+          };
         };
         return sub(List.length(l$1), l$1)[0];
       } else {
diff --git a/lib/js/setLabels.js b/lib/js/setLabels.js
index 85c913e920..2b2af67dce 100644
--- a/lib/js/setLabels.js
+++ b/lib/js/setLabels.js
@@ -31,12 +31,11 @@ function Make(Ord) {
     hr = typeof r !== "object" ? 0 : r.h;
     if (hl > (hr + 2 | 0)) {
       if (typeof l !== "object") {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Set.bal"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Set.bal",
+          Error: new Error()
+        };
       }
       let lr = l.r;
       let lv = l.v;
@@ -47,12 +46,11 @@ function Make(Ord) {
       if (typeof lr === "object") {
         return create(create(ll, lv, lr.l), lr.v, create(lr.r, v, r));
       }
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     if (hr <= (hl + 2 | 0)) {
       return {
@@ -64,12 +62,11 @@ function Make(Ord) {
       };
     }
     if (typeof r !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.bal"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.bal",
+        Error: new Error()
+      };
     }
     let rr = r.r;
     let rv = r.v;
@@ -80,12 +77,11 @@ function Make(Ord) {
     if (typeof rl === "object") {
       return create(create(l, v, rl.l), rl.v, create(rl.r, rv, rr));
     }
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "Set.bal"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "Set.bal",
+      Error: new Error()
+    };
   };
   let add = (x, param) => {
     if (typeof param !== "object") {
@@ -161,11 +157,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let l = param.l;
       if (typeof l !== "object") {
@@ -193,11 +188,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let r = param.r;
       if (typeof r !== "object") {
@@ -223,12 +217,11 @@ function Make(Ord) {
   };
   let remove_min_elt = param => {
     if (typeof param !== "object") {
-      throw new Error("Invalid_argument", {
-        cause: {
-          RE_EXN_ID: "Invalid_argument",
-          _1: "Set.remove_min_elt"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Invalid_argument",
+        _1: "Set.remove_min_elt",
+        Error: new Error()
+      };
     }
     let l = param.l;
     if (typeof l !== "object") {
@@ -618,11 +611,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       let c = Ord.compare(x, v);
@@ -654,11 +646,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -720,11 +711,10 @@ function Make(Ord) {
     while (true) {
       let param = _param;
       if (typeof param !== "object") {
-        throw new Error("Not_found", {
-          cause: {
-            RE_EXN_ID: "Not_found"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Not_found",
+          Error: new Error()
+        };
       }
       let v = param.v;
       if (f(v)) {
@@ -894,16 +884,15 @@ function Make(Ord) {
           match$4[1]
         ];
       }
-      throw new Error("Assert_failure", {
-        cause: {
-          RE_EXN_ID: "Assert_failure",
-          _1: [
-            "setLabels.res",
-            691,
-            20
-          ]
-        }
-      });
+      throw {
+        RE_EXN_ID: "Assert_failure",
+        _1: [
+          "setLabels.res",
+          691,
+          20
+        ],
+        Error: new Error()
+      };
     };
     return sub(List.length(l), l)[0];
   };
diff --git a/lib/js/sort.js b/lib/js/sort.js
index d4556f5ccd..f065720f4d 100644
--- a/lib/js/sort.js
+++ b/lib/js/sort.js
@@ -114,12 +114,11 @@ function array(cmp, arr) {
       let i = lo + 1 | 0;
       let j = hi - 1 | 0;
       if (!cmp(pivot, arr[hi]) || !cmp(arr[lo], pivot)) {
-        throw new Error("Invalid_argument", {
-          cause: {
-            RE_EXN_ID: "Invalid_argument",
-            _1: "Sort.array"
-          }
-        });
+        throw {
+          RE_EXN_ID: "Invalid_argument",
+          _1: "Sort.array",
+          Error: new Error()
+        };
       }
       while (i < j) {
         while (!cmp(pivot, arr[i])) {
diff --git a/lib/js/stack.js b/lib/js/stack.js
index e90720d44c..8e9b67f45e 100644
--- a/lib/js/stack.js
+++ b/lib/js/stack.js
@@ -39,11 +39,10 @@ function pop(s) {
     s.len = s.len - 1 | 0;
     return match.hd;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function top(s) {
@@ -51,11 +50,10 @@ function top(s) {
   if (match) {
     return match.hd;
   }
-  throw new Error(Empty, {
-    cause: {
-      RE_EXN_ID: Empty
-    }
-  });
+  throw {
+    RE_EXN_ID: Empty,
+    Error: new Error()
+  };
 }
 
 function is_empty(s) {
diff --git a/lib/js/stream.js b/lib/js/stream.js
index ac7705230d..d4c089ee7b 100644
--- a/lib/js/stream.js
+++ b/lib/js/stream.js
@@ -54,16 +54,15 @@ function get_data(count, _d) {
             }
           };
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "stream.res",
-              53,
-              13
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "stream.res",
+            53,
+            13
+          ],
+          Error: new Error()
+        };
       case "Slazy" :
         _d = CamlinternalLazy.force(d._0);
         continue;
@@ -116,16 +115,15 @@ function peek_data(s) {
           s.data = d;
           return Caml_option.some(d._0);
         }
-        throw new Error("Assert_failure", {
-          cause: {
-            RE_EXN_ID: "Assert_failure",
-            _1: [
-              "stream.res",
-              83,
-              13
-            ]
-          }
-        });
+        throw {
+          RE_EXN_ID: "Assert_failure",
+          _1: [
+            "stream.res",
+            83,
+            13
+          ],
+          Error: new Error()
+        };
       case "Slazy" :
         s.data = CamlinternalLazy.force(f._0);
         continue;
@@ -234,11 +232,10 @@ function next(s) {
     junk(s);
     return Caml_option.valFromOption(a);
   }
-  throw new Error(Failure, {
-    cause: {
-      RE_EXN_ID: Failure
-    }
-  });
+  throw {
+    RE_EXN_ID: Failure,
+    Error: new Error()
+  };
 }
 
 function empty(s) {
@@ -246,11 +243,10 @@ function empty(s) {
   if (match === undefined) {
     return;
   }
-  throw new Error(Failure, {
-    cause: {
-      RE_EXN_ID: Failure
-    }
-  });
+  throw {
+    RE_EXN_ID: Failure,
+    Error: new Error()
+  };
 }
 
 function iter(f, strm) {
diff --git a/lib/js/string.js b/lib/js/string.js
index 7a0052196d..4da913526c 100644
--- a/lib/js/string.js
+++ b/lib/js/string.js
@@ -90,11 +90,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -129,12 +128,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -142,12 +140,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -156,11 +153,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -176,12 +172,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -206,12 +201,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -219,12 +213,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -234,9 +227,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -246,12 +237,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -261,9 +251,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/stringLabels.js b/lib/js/stringLabels.js
index 40f76f7f90..9e9861db12 100644
--- a/lib/js/stringLabels.js
+++ b/lib/js/stringLabels.js
@@ -92,11 +92,10 @@ function index_rec(s, lim, _i, c) {
   while (true) {
     let i = _i;
     if (i >= lim) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -131,12 +130,11 @@ function index_opt(s, c) {
 function index_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from / Bytes.index_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from / Bytes.index_from",
+      Error: new Error()
+    };
   }
   return index_rec(s, l, i, c);
 }
@@ -144,12 +142,11 @@ function index_from(s, i, c) {
 function index_from_opt(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.index_from_opt / Bytes.index_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.index_from_opt / Bytes.index_from_opt",
+      Error: new Error()
+    };
   }
   return index_rec_opt(s, l, i, c);
 }
@@ -158,11 +155,10 @@ function rindex_rec(s, _i, c) {
   while (true) {
     let i = _i;
     if (i < 0) {
-      throw new Error("Not_found", {
-        cause: {
-          RE_EXN_ID: "Not_found"
-        }
-      });
+      throw {
+        RE_EXN_ID: "Not_found",
+        Error: new Error()
+      };
     }
     if (s.codePointAt(i) === c) {
       return i;
@@ -178,12 +174,11 @@ function rindex(s, c) {
 
 function rindex_from(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from / Bytes.rindex_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from / Bytes.rindex_from",
+      Error: new Error()
+    };
   }
   return rindex_rec(s, i, c);
 }
@@ -208,12 +203,11 @@ function rindex_opt(s, c) {
 
 function rindex_from_opt(s, i, c) {
   if (i < -1 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rindex_from_opt / Bytes.rindex_from_opt"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rindex_from_opt / Bytes.rindex_from_opt",
+      Error: new Error()
+    };
   }
   return rindex_rec_opt(s, i, c);
 }
@@ -221,12 +215,11 @@ function rindex_from_opt(s, i, c) {
 function contains_from(s, i, c) {
   let l = s.length;
   if (i < 0 || i > l) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.contains_from / Bytes.contains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.contains_from / Bytes.contains_from",
+      Error: new Error()
+    };
   }
   try {
     index_rec(s, l, i, c);
@@ -236,9 +229,7 @@ function contains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
@@ -248,12 +239,11 @@ function contains(s, c) {
 
 function rcontains_from(s, i, c) {
   if (i < 0 || i >= s.length) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "String.rcontains_from / Bytes.rcontains_from"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "String.rcontains_from / Bytes.rcontains_from",
+      Error: new Error()
+    };
   }
   try {
     rindex_rec(s, i, c);
@@ -263,9 +253,7 @@ function rcontains_from(s, i, c) {
     if (exn.RE_EXN_ID === "Not_found") {
       return false;
     }
-    throw new Error(exn.RE_EXN_ID, {
-      cause: exn
-    });
+    throw exn;
   }
 }
 
diff --git a/lib/js/uchar.js b/lib/js/uchar.js
index 43a6f0349e..afb17c438f 100644
--- a/lib/js/uchar.js
+++ b/lib/js/uchar.js
@@ -16,12 +16,11 @@ function succ(u) {
     return 57344;
   }
   if (u === 1114111) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "U+10FFFF has no successor"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "U+10FFFF has no successor",
+      Error: new Error()
+    };
   }
   return u + 1 | 0;
 }
@@ -31,12 +30,11 @@ function pred(u) {
     return 55295;
   }
   if (u === 0) {
-    throw new Error("Invalid_argument", {
-      cause: {
-        RE_EXN_ID: "Invalid_argument",
-        _1: "U+0000 has no predecessor"
-      }
-    });
+    throw {
+      RE_EXN_ID: "Invalid_argument",
+      _1: "U+0000 has no predecessor",
+      Error: new Error()
+    };
   }
   return u - 1 | 0;
 }
@@ -56,12 +54,11 @@ function of_int(i) {
     return i;
   }
   let s = err_not_sv(i);
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function is_char(u) {
@@ -77,12 +74,11 @@ function to_char(u) {
     return u;
   }
   let s = err_not_latin1(u);
-  throw new Error("Invalid_argument", {
-    cause: {
-      RE_EXN_ID: "Invalid_argument",
-      _1: s
-    }
-  });
+  throw {
+    RE_EXN_ID: "Invalid_argument",
+    _1: s,
+    Error: new Error()
+  };
 }
 
 function unsafe_to_char(prim) {