jsx/fix: mangle generated type variables from newtypes

Author: glennsl

src/reactjs_jsx_ppx_v3.ml

@@ -234,10 +234,11 @@ let makeExternalDecl fnName loc namedArgListWithKeyAndRef namedTypeList =
   [@@raises Invalid_argument]
 
 let newtypeToVar newtype type_ =
+  let var_desc = Ptyp_var ("type-" ^ newtype) in
   let typ (mapper : Ast_mapper.mapper) typ =
     match typ.ptyp_desc with
     | Ptyp_constr ({txt = Lident name}, _) when name = newtype ->
-      {typ with ptyp_desc = Ptyp_var newtype}
+      {typ with ptyp_desc = var_desc}
     | _ -> Ast_mapper.default_mapper.typ mapper typ
   in
   let mapper = {Ast_mapper.default_mapper with typ} in

tests/ppx/react/expected/newtype.res.txt

@@ -1,14 +1,15 @@
 @obj
 external makeProps: (
-  ~a: 'a,
-  ~b: array<option<[#Foo('a)]>>,
+  ~a: '\"type-a",
+  ~b: array<option<[#Foo('\"type-a")]>>,
+  ~c: 'a,
   ~key: string=?,
   unit,
-) => {"a": 'a, "b": array<option<[#Foo('a)]>>} = ""
-let make = (type a, ~a: a, ~b: array<option<[#Foo(a)]>>, _) =>
+) => {"a": '\"type-a", "b": array<option<[#Foo('\"type-a")]>>, "c": 'a} = ""
+let make = (type a, ~a: a, ~b: array<option<[#Foo(a)]>>, ~c: 'a, _) =>
   ReactDOMRe.createDOMElementVariadic("div", [])
 let make = {
-  let \"Newtype" = (\"Props": {"a": 'a, "b": array<option<[#Foo('a)]>>}) =>
-    make(~b=\"Props"["b"], ~a=\"Props"["a"])
+  let \"Newtype" = (\"Props": {"a": '\"type-a", "b": array<option<[#Foo('\"type-a")]>>, "c": 'a}) =>
+    make(~c=\"Props"["c"], ~b=\"Props"["b"], ~a=\"Props"["a"])
   \"Newtype"
 }

tests/ppx/react/newtype.res

@@ -1,2 +1,2 @@
 @react.component
-let make = (type a, ~a: a, ~b: array<option<[#Foo(a)]>>, _) => <div />
+let make = (type a, ~a: a, ~b: array<option<[#Foo(a)]>>, ~c: 'a, _) => <div />