diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d1196006f..4132fef41e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,8 @@
 - Use latest compiler for tests. https://github.com/rescript-lang/rescript/pull/7186
 - Added infra to modernise AST: theres' Parsetree, Parsetree0 (legacy), and conversion functions to keep compatibility with PPX. https://github.com/rescript-lang/rescript/pull/7185
 - Ast cleanup: remove exp object and exp unreachable. https://github.com/rescript-lang/rescript/pull/7189
+- Ast cleanup: explicit representation for optional record fields in types. https://github.com/rescript-lang/rescript/pull/7190 https://github.com/rescript-lang/rescript/pull/7191
+
 
 # 12.0.0-alpha.5
 
diff --git a/analysis/src/CreateInterface.ml b/analysis/src/CreateInterface.ml
index a3c19666c1..ebb936867f 100644
--- a/analysis/src/CreateInterface.ml
+++ b/analysis/src/CreateInterface.ml
@@ -145,12 +145,7 @@ let printSignature ~extractor ~signature =
   let rec processSignature ~indent (signature : Types.signature) : unit =
     match signature with
     | Sig_type
-        ( propsId,
-          {
-            type_params;
-            type_kind = Type_record (labelDecls, recordRepresentation);
-          },
-          _ )
+        (propsId, {type_params; type_kind = Type_record (labelDecls, _)}, _)
       :: Sig_value (makeId (* make *), makeValueDesc)
       :: rest
       when Ident.name propsId = "props"
@@ -175,12 +170,7 @@ let printSignature ~extractor ~signature =
             in
             let lblName = labelDecl.ld_id |> Ident.name in
             let lbl =
-              let optLbls =
-                match recordRepresentation with
-                | Record_optional_labels optLbls -> optLbls
-                | _ -> []
-              in
-              if List.mem lblName optLbls then Asttypes.Optional lblName
+              if labelDecl.ld_optional then Asttypes.Optional lblName
               else Labelled lblName
             in
             {retType with desc = Tarrow (lbl, propType, mkFunType rest, Cok)}
diff --git a/compiler/core/js_dump.ml b/compiler/core/js_dump.ml
index 792a4d3c86..d0ccc08f12 100644
--- a/compiler/core/js_dump.ml
+++ b/compiler/core/js_dump.ml
@@ -759,24 +759,19 @@ and expression_desc cxt ~(level : int) f x : cxt =
            Ext_list.map_combine fields el (fun x ->
                Js_op.Lit (Ext_ident.convert x)) ))
   (*name convention of Record is slight different from modules*)
-  | Caml_block (el, mutable_flag, _, Blk_record {fields; record_repr}) -> (
+  | Caml_block (el, mutable_flag, _, Blk_record {fields}) ->
     if
       Array.length fields <> 0
-      && Ext_array.for_alli fields (fun i v -> string_of_int i = v)
+      && Ext_array.for_alli fields (fun i (v, _) -> string_of_int i = v)
     then expression_desc cxt ~level f (Array (el, mutable_flag))
     else
-      match record_repr with
-      | Record_regular ->
-        expression_desc cxt ~level f
-          (Object (None, Ext_list.combine_array fields el (fun i -> Js_op.Lit i)))
-      | Record_optional ->
-        let fields =
-          Ext_list.array_list_filter_map fields el (fun f x ->
-              match x.expression_desc with
-              | Undefined _ -> None
-              | _ -> Some (Js_op.Lit f, x))
-        in
-        expression_desc cxt ~level f (Object (None, fields)))
+      let fields =
+        Ext_list.array_list_filter_map fields el (fun (f, opt) x ->
+            match x.expression_desc with
+            | Undefined _ when opt -> None
+            | _ -> Some (Js_op.Lit f, x))
+      in
+      expression_desc cxt ~level f (Object (None, fields))
   | Caml_block (el, _, _, Blk_poly_var _) -> (
     match el with
     | [tag; value] ->
@@ -794,14 +789,7 @@ and expression_desc cxt ~(level : int) f x : cxt =
     let untagged = Ast_untagged_variants.process_untagged p.attrs in
     let objs =
       let tails =
-        Ext_list.combine_array_append p.fields el
-          (if !Js_config.debug then [(name_symbol, E.str p.name)] else [])
-          (fun i -> Js_op.Lit i)
-      in
-      let is_optional (pname : Js_op.property_name) =
-        match pname with
-        | Lit n -> Ext_list.mem_string p.optional_labels n
-        | Symbol_name -> false
+        Ext_list.combine_array p.fields el (fun (i, opt) -> (Js_op.Lit i, opt))
       in
       let tag_name =
         match Ast_untagged_variants.process_tag_name p.attrs with
@@ -809,13 +797,10 @@ and expression_desc cxt ~(level : int) f x : cxt =
         | Some s -> s
       in
       let tails =
-        match p.optional_labels with
-        | [] -> tails
-        | _ ->
-          Ext_list.filter_map tails (fun (f, x) ->
-              match x.expression_desc with
-              | Undefined _ when is_optional f -> None
-              | _ -> Some (f, x))
+        Ext_list.filter_map tails (fun ((f, optional), x) ->
+            match x.expression_desc with
+            | Undefined _ when optional -> None
+            | _ -> Some (f, x))
       in
       if untagged then tails
       else
diff --git a/compiler/core/js_pass_flatten_and_mark_dead.ml b/compiler/core/js_pass_flatten_and_mark_dead.ml
index 23c34f23eb..830f0ddde3 100644
--- a/compiler/core/js_pass_flatten_and_mark_dead.ml
+++ b/compiler/core/js_pass_flatten_and_mark_dead.ml
@@ -207,9 +207,8 @@ let subst_map (substitution : J.expression Hash_ident.t) =
                         match Ext_list.nth_opt fields i with
                         | None -> Printf.sprintf "%d" i
                         | Some x -> x)
-                      | Blk_record {fields} ->
-                        Ext_array.get_or fields i (fun _ ->
-                            Printf.sprintf "%d" i)
+                      | Blk_record {fields} -> (
+                        try fst fields.(i) with _ -> Printf.sprintf "%d" i)
                       | _ -> Printf.sprintf "%d" i)
                   in
                   (i + 1, E.var match_id :: e, (match_id, v') :: acc))
diff --git a/compiler/core/lam_compile.ml b/compiler/core/lam_compile.ml
index 22b3ffa2b8..4db63e7711 100644
--- a/compiler/core/lam_compile.ml
+++ b/compiler/core/lam_compile.ml
@@ -425,9 +425,9 @@ let compile output_prefix =
                  S.exp
                    (Js_of_lam_block.set_field
                       (match tag_info with
-                      | Blk_record {fields = xs} -> Fld_record_set xs.(i)
+                      | Blk_record {fields = xs} -> Fld_record_set (fst xs.(i))
                       | Blk_record_inlined xs ->
-                        Fld_record_inline_set xs.fields.(i)
+                        Fld_record_inline_set (fst xs.fields.(i))
                       | Blk_constructor p -> (
                         let is_cons = p.name = Literals.cons in
                         match (is_cons, i) with
diff --git a/compiler/core/lam_convert.ml b/compiler/core/lam_convert.ml
index 74131236ab..7c877cefb1 100644
--- a/compiler/core/lam_convert.ml
+++ b/compiler/core/lam_convert.ml
@@ -34,9 +34,8 @@ let lam_extension_id loc (head : Lam.t) =
 let lazy_block_info : Lam_tag_info.t =
   Blk_record
     {
-      fields = [|Literals.lazy_done; Literals.lazy_val|];
+      fields = [|(Literals.lazy_done, false); (Literals.lazy_val, false)|];
       mutable_flag = Mutable;
-      record_repr = Record_regular;
     }
 
 (** A conservative approach to avoid packing exceptions
diff --git a/compiler/core/lam_util.ml b/compiler/core/lam_util.ml
index 44cd7c029d..7ea859f6be 100644
--- a/compiler/core/lam_util.ml
+++ b/compiler/core/lam_util.ml
@@ -198,7 +198,7 @@ let field_flatten_get
       | Fld_record {name} ->
         let found = ref None in
         for i = 0 to Array.length fields - 1 do
-          if fields.(i) = name then found := Ext_list.nth_opt ls i done;
+          if fst(fields.(i)) = name then found := Ext_list.nth_opt ls i done;
         (match !found with
         | Some c -> Lam.const c
         | None  -> lam())
diff --git a/compiler/gentype/TranslateSignatureFromTypes.ml b/compiler/gentype/TranslateSignatureFromTypes.ml
index 1b0e4625be..2a12d6e350 100644
--- a/compiler/gentype/TranslateSignatureFromTypes.ml
+++ b/compiler/gentype/TranslateSignatureFromTypes.ml
@@ -12,9 +12,8 @@ let translate_type_declaration_from_types ~config ~output_file_relative
     Log_.item "Translate Types.type_declaration %s\n" type_name;
   let declaration_kind =
     match type_kind with
-    | Type_record (label_declarations, record_representation) ->
-      TranslateTypeDeclarations.RecordDeclarationFromTypes
-        (label_declarations, record_representation)
+    | Type_record (label_declarations, _) ->
+      TranslateTypeDeclarations.RecordDeclarationFromTypes label_declarations
     | Type_variant constructor_declarations
       when not
              (TranslateTypeDeclarations.has_some_gadt_leaf
diff --git a/compiler/gentype/TranslateTypeDeclarations.ml b/compiler/gentype/TranslateTypeDeclarations.ml
index 08b8075603..2768bdf343 100644
--- a/compiler/gentype/TranslateTypeDeclarations.ml
+++ b/compiler/gentype/TranslateTypeDeclarations.ml
@@ -1,8 +1,7 @@
 open GenTypeCommon
 
 type declaration_kind =
-  | RecordDeclarationFromTypes of
-      Types.label_declaration list * Types.record_representation
+  | RecordDeclarationFromTypes of Types.label_declaration list
   | GeneralDeclaration of Typedtree.core_type option
   | GeneralDeclarationFromTypes of Types.type_expr option
       (** As the above, but from Types not Typedtree *)
@@ -86,16 +85,12 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
     in
     {CodeItem.import_types; export_from_type_declaration}
   in
-  let translate_label_declarations ?(inline = false) ~record_representation
-      label_declarations =
-    let is_optional l =
-      match record_representation with
-      | Types.Record_optional_labels lbls -> List.mem l lbls
-      | _ -> false
-    in
+  let translate_label_declarations ?(inline = false) label_declarations =
     let field_translations =
       label_declarations
-      |> List.map (fun {Types.ld_id; ld_mutable; ld_type; ld_attributes} ->
+      |> List.map
+           (fun
+             {Types.ld_id; ld_mutable; ld_optional; ld_type; ld_attributes} ->
              let name =
                rename_record_field ~attributes:ld_attributes
                  ~name:(ld_id |> Ident.name)
@@ -107,6 +102,7 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
              in
              ( name,
                mutability,
+               ld_optional,
                ld_type
                |> TranslateTypeExprFromTypes.translate_type_expr_from_types
                     ~config ~type_env,
@@ -114,7 +110,8 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
     in
     let dependencies =
       field_translations
-      |> List.map (fun (_, _, {TranslateTypeExprFromTypes.dependencies}, _) ->
+      |> List.map
+           (fun (_, _, _, {TranslateTypeExprFromTypes.dependencies}, _) ->
              dependencies)
       |> List.concat
     in
@@ -122,10 +119,15 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
       field_translations
       |> List.map
            (fun
-             (name, mutable_, {TranslateTypeExprFromTypes.type_}, doc_string) ->
+             ( name,
+               mutable_,
+               optional_,
+               {TranslateTypeExprFromTypes.type_},
+               doc_string )
+           ->
              let optional, type1 =
                match type_ with
-               | Option type1 when is_optional name -> (Optional, type1)
+               | Option type1 when optional_ -> (Optional, type1)
                | _ -> (Mandatory, type_)
              in
              {mutable_; name_js = name; optional; type_ = type1; doc_string})
@@ -216,10 +218,9 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
     in
     {translation with type_} |> handle_general_declaration
     |> return_type_declaration
-  | RecordDeclarationFromTypes (label_declarations, record_representation), None
-    ->
+  | RecordDeclarationFromTypes label_declarations, None ->
     let {TranslateTypeExprFromTypes.dependencies; type_} =
-      label_declarations |> translate_label_declarations ~record_representation
+      label_declarations |> translate_label_declarations
     in
     let import_types =
       dependencies
@@ -250,8 +251,7 @@ let traslate_declaration_kind ~config ~loc ~output_file_relative ~resolver
                | Cstr_record label_declarations ->
                  [
                    label_declarations
-                   |> translate_label_declarations ~inline:true
-                        ~record_representation:Types.Record_regular;
+                   |> translate_label_declarations ~inline:true;
                  ]
              in
              let arg_types =
@@ -334,8 +334,8 @@ let translate_type_declaration ~config ~output_file_relative ~resolver ~type_env
   in
   let declaration_kind =
     match typ_type.type_kind with
-    | Type_record (label_declarations, record_representation) ->
-      RecordDeclarationFromTypes (label_declarations, record_representation)
+    | Type_record (label_declarations, _) ->
+      RecordDeclarationFromTypes label_declarations
     | Type_variant constructor_declarations ->
       VariantDeclarationFromTypes constructor_declarations
     | Type_abstract -> GeneralDeclaration typ_manifest
diff --git a/compiler/ml/ctype.ml b/compiler/ml/ctype.ml
index ec3d3f96e0..14ae92491b 100644
--- a/compiler/ml/ctype.ml
+++ b/compiler/ml/ctype.ml
@@ -2046,6 +2046,7 @@ and mcomp_record_description type_pairs env =
       if
         Ident.name l1.ld_id = Ident.name l2.ld_id
         && l1.ld_mutable = l2.ld_mutable
+        && l1.ld_optional = l2.ld_optional
       then iter xs ys
       else raise (Unify [])
     | [], [] -> ()
@@ -3721,8 +3722,7 @@ let rec subtype_rec env trace t1 t2 cstrs =
             (_, _, {type_kind = Type_record (fields2, repr2)}) ) ->
           let same_repr =
             match (repr1, repr2) with
-            | ( (Record_regular | Record_optional_labels _),
-                (Record_regular | Record_optional_labels _) ) ->
+            | Record_regular, Record_regular ->
               true (* handled in the fields checks *)
             | Record_unboxed b1, Record_unboxed b2 -> b1 = b2
             | Record_inlined _, Record_inlined _ -> repr1 = repr2
@@ -3731,7 +3731,7 @@ let rec subtype_rec env trace t1 t2 cstrs =
           in
           if same_repr then
             let violation, tl1, tl2 =
-              Record_coercion.check_record_fields ~repr1 ~repr2 fields1 fields2
+              Record_coercion.check_record_fields fields1 fields2
             in
             if violation then (trace, t1, t2, !univar_pairs) :: cstrs
             else subtype_list env trace tl1 tl2 cstrs
diff --git a/compiler/ml/datarepr.ml b/compiler/ml/datarepr.ml
index 1153a82bdb..9e37269deb 100644
--- a/compiler/ml/datarepr.ml
+++ b/compiler/ml/datarepr.ml
@@ -128,13 +128,6 @@ let constructor_descrs ty_path decl cstrs =
             describe_constructors idx_const (idx_nonconst + 1) rem )
       in
       let cstr_name = Ident.name cd_id in
-      let optional_labels =
-        match cd_args with
-        | Cstr_tuple _ -> []
-        | Cstr_record lbls ->
-          Ext_list.filter_map lbls (fun {ld_id; ld_optional} ->
-              if ld_optional then Some ld_id.name else None)
-      in
       let existentials, cstr_args, cstr_inlined =
         let representation =
           if decl.type_unboxed.unboxed then Record_unboxed true
@@ -144,7 +137,6 @@ let constructor_descrs ty_path decl cstrs =
                 tag = idx_nonconst;
                 name = cstr_name;
                 num_nonconsts = !num_nonconsts;
-                optional_labels;
                 attrs = cd_attributes;
               }
         in
@@ -232,6 +224,7 @@ let dummy_label =
     lbl_res = none;
     lbl_arg = none;
     lbl_mut = Immutable;
+    lbl_optional = false;
     lbl_pos = -1;
     lbl_all = [||];
     lbl_repres = Record_regular;
@@ -251,6 +244,7 @@ let label_descrs ty_res lbls repres priv =
           lbl_res = ty_res;
           lbl_arg = l.ld_type;
           lbl_mut = l.ld_mutable;
+          lbl_optional = l.ld_optional;
           lbl_pos = num;
           lbl_all = all_labels;
           lbl_repres = repres;
diff --git a/compiler/ml/includecore.ml b/compiler/ml/includecore.ml
index 0703e06ddc..b1db9e5f16 100644
--- a/compiler/ml/includecore.ml
+++ b/compiler/ml/includecore.ml
@@ -147,6 +147,7 @@ type type_mismatch =
   | Variance
   | Field_type of Ident.t
   | Field_mutable of Ident.t
+  | Field_optional of Ident.t
   | Field_arity of Ident.t
   | Field_names of int * string * string
   | Field_missing of bool * Ident.t
@@ -168,6 +169,8 @@ let report_type_mismatch0 first second decl ppf err =
   | Field_type s -> pr "The types for field %s are not equal" (Ident.name s)
   | Field_mutable s ->
     pr "The mutability of field %s is different" (Ident.name s)
+  | Field_optional s ->
+    pr "The optional attribute of field %s is different" (Ident.name s)
   | Field_arity s -> pr "The arities for field %s differ" (Ident.name s)
   | Field_names (n, name1, name2) ->
     pr "Fields number %i have different names, %s and %s" n name1 name2
@@ -175,21 +178,8 @@ let report_type_mismatch0 first second decl ppf err =
     pr "The field %s is only present in %s %s" (Ident.name s)
       (if b then second else first)
       decl
-  | Record_representation (rep1, rep2) -> (
-    let default () = pr "Their internal representations differ" in
-    match (rep1, rep2) with
-    | Record_optional_labels lbls1, Record_optional_labels lbls2 -> (
-      let only_in_lhs =
-        Ext_list.find_first lbls1 (fun l -> not (Ext_list.mem_string lbls2 l))
-      in
-      let only_in_rhs =
-        Ext_list.find_first lbls2 (fun l -> not (Ext_list.mem_string lbls1 l))
-      in
-      match (only_in_lhs, only_in_rhs) with
-      | Some l, _ -> pr "@optional label %s only in %s" l second
-      | _, Some l -> pr "@optional label %s only in %s" l first
-      | None, None -> default ())
-    | _ -> default ())
+  | Record_representation (_rep1, _rep2) ->
+    pr "Their internal representations differ"
   | Unboxed_representation b ->
     pr "Their internal representations differ:@ %s %s %s"
       (if b then second else first)
@@ -280,6 +270,7 @@ and compare_records ~loc env params1_ params2_ n_
       if Ident.name ld1.ld_id <> Ident.name ld2.ld_id then
         [Field_names (n, ld1.ld_id.name, ld2.ld_id.name)]
       else if ld1.ld_mutable <> ld2.ld_mutable then [Field_mutable ld1.ld_id]
+      else if ld1.ld_optional <> ld2.ld_optional then [Field_optional ld1.ld_id]
       else (
         Builtin_attributes.check_deprecated_mutable_inclusion ~def:ld1.ld_loc
           ~use:ld2.ld_loc loc ld1.ld_attributes ld2.ld_attributes
diff --git a/compiler/ml/includecore.mli b/compiler/ml/includecore.mli
index 20ed150639..aec316d449 100644
--- a/compiler/ml/includecore.mli
+++ b/compiler/ml/includecore.mli
@@ -29,6 +29,7 @@ type type_mismatch =
   | Variance
   | Field_type of Ident.t
   | Field_mutable of Ident.t
+  | Field_optional of Ident.t
   | Field_arity of Ident.t
   | Field_names of int * string * string
   | Field_missing of bool * Ident.t
diff --git a/compiler/ml/lambda.ml b/compiler/ml/lambda.ml
index fcd1dc86ca..63c5880ef1 100644
--- a/compiler/ml/lambda.ml
+++ b/compiler/ml/lambda.ml
@@ -15,8 +15,6 @@
 
 type loc_kind = Loc_FILE | Loc_LINE | Loc_MODULE | Loc_LOC | Loc_POS
 
-type record_repr = Record_regular | Record_optional
-
 type tag_info =
   | Blk_constructor of {
       name: string;
@@ -28,17 +26,15 @@ type tag_info =
       name: string;
       num_nonconst: int;
       tag: int;
-      optional_labels: string list;
-      fields: string array;
+      fields: (string * bool (* optional *)) array;
       mutable_flag: Asttypes.mutable_flag;
       attrs: Parsetree.attributes;
     }
   | Blk_tuple
   | Blk_poly_var of string
   | Blk_record of {
-      fields: string array;
+      fields: (string * bool (* optional *)) array;
       mutable_flag: Asttypes.mutable_flag;
-      record_repr: record_repr;
     }
   | Blk_module of string list
   | Blk_module_export of Ident.t list
@@ -88,12 +84,13 @@ let find_name (attr : Parsetree.attribute) =
     Some s
   | _ -> None
 
-let blk_record (fields : (label * _) array) mut record_repr =
+let blk_record (fields : (label * _) array) mut =
   let all_labels_info =
     Ext_array.map fields (fun (lbl, _) ->
-        Ext_list.find_def lbl.lbl_attributes find_name lbl.lbl_name)
+        ( Ext_list.find_def lbl.lbl_attributes find_name lbl.lbl_name,
+          lbl.lbl_optional ))
   in
-  Blk_record {fields = all_labels_info; mutable_flag = mut; record_repr}
+  Blk_record {fields = all_labels_info; mutable_flag = mut}
 
 let blk_record_ext fields mutable_flag =
   let all_labels_info =
@@ -104,24 +101,18 @@ let blk_record_ext fields mutable_flag =
   in
   Blk_record_ext {fields = all_labels_info; mutable_flag}
 
-let blk_record_inlined fields name num_nonconst optional_labels ~tag ~attrs
-    mutable_flag =
+let blk_record_inlined fields name num_nonconst ~tag ~attrs mutable_flag =
   let fields =
     Array.map
       (fun ((lbl : label), _) ->
-        Ext_list.find_def lbl.lbl_attributes find_name lbl.lbl_name)
+        ( Ext_list.find_def lbl.lbl_attributes find_name lbl.lbl_name,
+          lbl.lbl_optional ))
       fields
   in
-  Blk_record_inlined
-    {fields; name; num_nonconst; tag; mutable_flag; optional_labels; attrs}
+  Blk_record_inlined {fields; name; num_nonconst; tag; mutable_flag; attrs}
 
 let ref_tag_info : tag_info =
-  Blk_record
-    {
-      fields = [|"contents"|];
-      mutable_flag = Mutable;
-      record_repr = Record_regular;
-    }
+  Blk_record {fields = [|("contents", false)|]; mutable_flag = Mutable}
 
 type field_dbg_info =
   | Fld_record of {name: string; mutable_flag: Asttypes.mutable_flag}
diff --git a/compiler/ml/lambda.mli b/compiler/ml/lambda.mli
index 7f506ac62d..cd0c26537f 100644
--- a/compiler/ml/lambda.mli
+++ b/compiler/ml/lambda.mli
@@ -19,8 +19,6 @@ open Asttypes
 
 type loc_kind = Loc_FILE | Loc_LINE | Loc_MODULE | Loc_LOC | Loc_POS
 
-type record_repr = Record_regular | Record_optional
-
 type tag_info =
   | Blk_constructor of {
       name: string;
@@ -32,17 +30,15 @@ type tag_info =
       name: string;
       num_nonconst: int;
       tag: int;
-      optional_labels: string list;
-      fields: string array;
+      fields: (string * bool (* optional *)) array;
       mutable_flag: mutable_flag;
       attrs: Parsetree.attributes;
     }
   | Blk_tuple
   | Blk_poly_var of string
   | Blk_record of {
-      fields: string array;
+      fields: (string * bool (* optional *)) array;
       mutable_flag: mutable_flag;
-      record_repr: record_repr;
     }
   | Blk_module of string list
   | Blk_module_export of Ident.t list
@@ -69,7 +65,6 @@ val mutable_flag_of_tag_info : tag_info -> mutable_flag
 val blk_record :
   (Types.label_description * Typedtree.record_label_definition) array ->
   mutable_flag ->
-  record_repr ->
   tag_info
 
 val blk_record_ext :
@@ -81,7 +76,6 @@ val blk_record_inlined :
   (Types.label_description * Typedtree.record_label_definition) array ->
   string ->
   int ->
-  string list ->
   tag:int ->
   attrs:Parsetree.attributes ->
   mutable_flag ->
diff --git a/compiler/ml/matching.ml b/compiler/ml/matching.ml
index 0b6b6f1f3e..8ff391dbbf 100644
--- a/compiler/ml/matching.ml
+++ b/compiler/ml/matching.ml
@@ -1530,7 +1530,7 @@ let make_record_matching loc all_labels def = function
         let access =
           match lbl.lbl_repres with
           | Record_float_unused -> assert false
-          | Record_regular | Record_optional_labels _ ->
+          | Record_regular ->
             Lprim (Pfield (lbl.lbl_pos, Lambda.fld_record lbl), [arg], loc)
           | Record_inlined _ ->
             Lprim
diff --git a/compiler/ml/parmatch.ml b/compiler/ml/parmatch.ml
index 64fcb67787..ad1c5b2d2a 100644
--- a/compiler/ml/parmatch.ml
+++ b/compiler/ml/parmatch.ml
@@ -528,8 +528,8 @@ let all_record_args lbls =
       (fun ((id, lbl, pat) as x) ->
         let lbl_is_optional () =
           match lbl.lbl_repres with
-          | Record_optional_labels labels -> List.mem lbl.lbl_name labels
-          | _ -> false
+          | Record_inlined _ -> false
+          | _ -> lbl.lbl_optional
         in
         let x =
           match pat.pat_desc with
diff --git a/compiler/ml/predef.ml b/compiler/ml/predef.ml
index 7cc92ddd58..d9a5deae72 100644
--- a/compiler/ml/predef.ml
+++ b/compiler/ml/predef.ml
@@ -316,7 +316,7 @@ let common_initial_env add_type add_extension empty_env =
                 ld_type = newgenty (Tconstr (path_option, [tvar], ref Mnil));
               };
             ],
-            Record_optional_labels [Ident.name ident_dict_magic_field_name] );
+            Record_regular );
     }
   and decl_uncurried =
     let tvar1, tvar2 = (newgenvar (), newgenvar ()) in
diff --git a/compiler/ml/printlambda.ml b/compiler/ml/printlambda.ml
index 4512355c34..6d4d0cebfe 100644
--- a/compiler/ml/printlambda.ml
+++ b/compiler/ml/printlambda.ml
@@ -97,14 +97,14 @@ let print_taginfo ppf = function
     fprintf ppf "%s/%i" name num_nonconst
   | Blk_poly_var name -> fprintf ppf "`%s" name
   | Blk_record {fields = ss} ->
-    fprintf ppf "[%s]" (String.concat ";" (Array.to_list ss))
+    fprintf ppf "[%s]" (String.concat ";" (List.map fst (Array.to_list ss)))
   | Blk_module ss -> fprintf ppf "[%s]" (String.concat ";" ss)
   | Blk_some -> fprintf ppf "some"
   | Blk_some_not_nested -> fprintf ppf "some_not_nested"
   | Blk_lazy_general -> fprintf ppf "lazy_general"
   | Blk_module_export _ -> fprintf ppf "module/exports"
   | Blk_record_inlined {fields = ss} ->
-    fprintf ppf "[%s]" (String.concat ";" (Array.to_list ss))
+    fprintf ppf "[%s]" (String.concat ";" (List.map fst (Array.to_list ss)))
 
 let primitive ppf = function
   | Pidentity -> fprintf ppf "id"
diff --git a/compiler/ml/printtyped.ml b/compiler/ml/printtyped.ml
index cc5df3479a..874f390ec0 100644
--- a/compiler/ml/printtyped.ml
+++ b/compiler/ml/printtyped.ml
@@ -130,8 +130,6 @@ let record_representation i ppf =
   function
   | Record_regular -> line i ppf "Record_regular\n"
   | Record_float_unused -> assert false
-  | Record_optional_labels lbls ->
-    line i ppf "Record_optional_labels %s\n" (lbls |> String.concat ", ")
   | Record_unboxed b -> line i ppf "Record_unboxed %b\n" b
   | Record_inlined {tag = i} -> line i ppf "Record_inlined %d\n" i
   | Record_extension -> line i ppf "Record_extension\n"
diff --git a/compiler/ml/rec_check.ml b/compiler/ml/rec_check.ml
index 9296ad086b..889056073e 100644
--- a/compiler/ml/rec_check.ml
+++ b/compiler/ml/rec_check.ml
@@ -261,9 +261,7 @@ let rec expression : Env.env -> Typedtree.expression -> Use.t =
       match rep with
       | Record_unboxed _ -> fun x -> x
       | Record_float_unused -> assert false
-      | Record_optional_labels _ | Record_regular | Record_inlined _
-      | Record_extension ->
-        Use.guard
+      | Record_regular | Record_inlined _ | Record_extension -> Use.guard
     in
     let field env = function
       | _, Kept _ -> Use.empty
diff --git a/compiler/ml/record_coercion.ml b/compiler/ml/record_coercion.ml
index 9a0c4eb747..0f2fbc96d6 100644
--- a/compiler/ml/record_coercion.ml
+++ b/compiler/ml/record_coercion.ml
@@ -1,18 +1,13 @@
-let check_record_fields ?repr1 ?repr2 (fields1 : Types.label_declaration list)
+let check_record_fields (fields1 : Types.label_declaration list)
     (fields2 : Types.label_declaration list) =
-  let field_is_optional id repr =
-    match repr with
-    | Some (Types.Record_optional_labels lbls) -> List.mem (Ident.name id) lbls
-    | _ -> false
-  in
   let violation = ref false in
   let label_decl_sub (acc1, acc2) (ld2 : Types.label_declaration) =
     match
       Ext_list.find_first fields1 (fun ld1 -> ld1.ld_id.name = ld2.ld_id.name)
     with
     | Some ld1 ->
-      if field_is_optional ld1.ld_id repr1 <> field_is_optional ld2.ld_id repr2
-      then (* optional field can't be modified *)
+      if ld1.ld_optional <> ld2.ld_optional then
+        (* optional field can't be modified *)
         violation := true;
       let get_as (({txt}, payload) : Parsetree.attribute) =
         if txt = "as" then Ast_payload.is_single_string payload else None
diff --git a/compiler/ml/translcore.ml b/compiler/ml/translcore.ml
index 27b8152d44..f84d38f92e 100644
--- a/compiler/ml/translcore.ml
+++ b/compiler/ml/translcore.ml
@@ -923,7 +923,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
     let targ = transl_exp arg in
     match lbl.lbl_repres with
     | Record_float_unused -> assert false
-    | Record_regular | Record_optional_labels _ ->
+    | Record_regular ->
       Lprim (Pfield (lbl.lbl_pos, Lambda.fld_record lbl), [targ], e.exp_loc)
     | Record_inlined _ ->
       Lprim
@@ -938,8 +938,7 @@ and transl_exp0 (e : Typedtree.expression) : Lambda.lambda =
     let access =
       match lbl.lbl_repres with
       | Record_float_unused -> assert false
-      | Record_regular | Record_optional_labels _ ->
-        Psetfield (lbl.lbl_pos, Lambda.fld_record_set lbl)
+      | Record_regular -> Psetfield (lbl.lbl_pos, Lambda.fld_record_set lbl)
       | Record_inlined _ ->
         Psetfield (lbl.lbl_pos, Lambda.fld_record_inline_set lbl)
       | Record_unboxed _ -> assert false
@@ -1159,6 +1158,7 @@ and transl_record loc env fields repres opt_init_expr =
     else lambda
   | _ -> (
     let size = Array.length fields in
+    let optional = Ext_array.exists fields (fun (ld, _) -> ld.lbl_optional) in
     (* Determine if there are "enough" fields (only relevant if this is a
        functional-style record update *)
     let no_init =
@@ -1167,12 +1167,7 @@ and transl_record loc env fields repres opt_init_expr =
       | _ -> false
     in
     if
-      no_init
-      || size < 20
-         &&
-         match repres with
-         | Record_optional_labels _ -> false
-         | _ -> true
+      no_init || (size < 20 && not optional)
       (* TODO: More strategies
          3 + 2 * List.length lbl_expr_list >= size (density)
       *)
@@ -1188,8 +1183,7 @@ and transl_record loc env fields repres opt_init_expr =
               let access =
                 match repres with
                 | Record_float_unused -> assert false
-                | Record_regular | Record_optional_labels _ ->
-                  Pfield (i, Lambda.fld_record lbl)
+                | Record_regular -> Pfield (i, Lambda.fld_record lbl)
                 | Record_inlined _ -> Pfield (i, Lambda.fld_record_inline lbl)
                 | Record_unboxed _ -> assert false
                 | Record_extension ->
@@ -1212,16 +1206,12 @@ and transl_record loc env fields repres opt_init_expr =
           match repres with
           | Record_float_unused -> assert false
           | Record_regular ->
-            Lconst
-              (Const_block (Lambda.blk_record fields mut Record_regular, cl))
-          | Record_optional_labels _ ->
-            Lconst
-              (Const_block (Lambda.blk_record fields mut Record_optional, cl))
-          | Record_inlined {tag; name; num_nonconsts; optional_labels; attrs} ->
+            Lconst (Const_block (Lambda.blk_record fields mut, cl))
+          | Record_inlined {tag; name; num_nonconsts; attrs} ->
             Lconst
               (Const_block
-                 ( Lambda.blk_record_inlined fields name num_nonconsts
-                     optional_labels ~tag ~attrs mut,
+                 ( Lambda.blk_record_inlined fields name num_nonconsts ~tag
+                     ~attrs mut,
                    cl ))
           | Record_unboxed _ ->
             Lconst
@@ -1232,19 +1222,13 @@ and transl_record loc env fields repres opt_init_expr =
         with Not_constant -> (
           match repres with
           | Record_regular ->
-            Lprim
-              (Pmakeblock (Lambda.blk_record fields mut Record_regular), ll, loc)
-          | Record_optional_labels _ ->
-            Lprim
-              ( Pmakeblock (Lambda.blk_record fields mut Record_optional),
-                ll,
-                loc )
+            Lprim (Pmakeblock (Lambda.blk_record fields mut), ll, loc)
           | Record_float_unused -> assert false
-          | Record_inlined {tag; name; num_nonconsts; optional_labels; attrs} ->
+          | Record_inlined {tag; name; num_nonconsts; attrs} ->
             Lprim
               ( Pmakeblock
-                  (Lambda.blk_record_inlined fields name num_nonconsts
-                     optional_labels ~tag ~attrs mut),
+                  (Lambda.blk_record_inlined fields name num_nonconsts ~tag
+                     ~attrs mut),
                 ll,
                 loc )
           | Record_unboxed _ -> (
@@ -1277,7 +1261,7 @@ and transl_record loc env fields repres opt_init_expr =
           let upd =
             match repres with
             | Record_float_unused -> assert false
-            | Record_regular | Record_optional_labels _ ->
+            | Record_regular ->
               Psetfield (lbl.lbl_pos, Lambda.fld_record_set lbl)
             | Record_inlined _ ->
               Psetfield (lbl.lbl_pos, Lambda.fld_record_inline_set lbl)
diff --git a/compiler/ml/typecore.ml b/compiler/ml/typecore.ml
index c5d1a7f8f7..b8481997a2 100644
--- a/compiler/ml/typecore.ml
+++ b/compiler/ml/typecore.ml
@@ -297,18 +297,7 @@ let extract_concrete_variant env ty =
   | p0, p, {type_kind = Type_open} -> (p0, p, [])
   | _ -> raise Not_found
 
-let has_optional_labels ld =
-  match ld.lbl_repres with
-  | Record_optional_labels _ -> true
-  | Record_inlined {optional_labels} -> optional_labels <> []
-  | _ -> false
-
-let label_is_optional ld =
-  match ld.lbl_repres with
-  | Record_optional_labels lbls -> Ext_list.mem_string lbls ld.lbl_name
-  | Record_inlined {optional_labels} ->
-    Ext_list.mem_string optional_labels ld.lbl_name
-  | _ -> false
+let label_is_optional ld = ld.lbl_optional
 
 let check_optional_attr env ld attrs loc =
   let check_redundant () =
@@ -960,7 +949,7 @@ module Label = NameChoice (struct
         lbl with
         lbl_name = name;
         lbl_pos = Array.length lbl.lbl_all;
-        lbl_repres = Record_optional_labels [name];
+        lbl_repres = Record_regular;
       }
     in
     let lbl_all_list = Array.to_list lbl.lbl_all @ [l] in
@@ -981,7 +970,8 @@ let disambiguate_label_by_ids closed ids labels =
   in
   let mandatory_labels_are_present num_ids lbl =
     (* check that all mandatory labels are present *)
-    if has_optional_labels lbl then (
+    let has_optional_labels = Ext_array.exists lbl.lbl_all label_is_optional in
+    if has_optional_labels then (
       let mandatory_lbls = ref 0 in
       Ext_array.iter lbl.lbl_all (fun l ->
           if not (label_is_optional l) then incr mandatory_lbls);
@@ -2645,15 +2635,8 @@ and type_expect_ ?type_clash_context ?in_function ?(recarg = Rejected) env sexp
           _ ) ->
         (label_descriptions, representation)
       | [], Some representation when lid_sexp_list = [] ->
-        let optional_labels =
-          match representation with
-          | Record_optional_labels optional_labels -> optional_labels
-          | Record_inlined {optional_labels} -> optional_labels
-          | _ -> []
-        in
         let filter_missing (ld : Types.label_declaration) =
-          let name = Ident.name ld.ld_id in
-          if List.mem name optional_labels then None else Some name
+          if ld.ld_optional then None else Some (Ident.name ld.ld_id)
         in
         let labels_missing = fields |> List.filter_map filter_missing in
         if labels_missing <> [] then
@@ -2668,7 +2651,7 @@ and type_expect_ ?type_clash_context ?in_function ?(recarg = Rejected) env sexp
                    } ));
         ([||], representation)
       | [], _ ->
-        if fields = [] && repr_opt <> None then ([||], Record_optional_labels [])
+        if fields = [] && repr_opt <> None then ([||], Record_regular)
         else raise (Error (loc, env, Empty_record_literal))
     in
     let labels_missing = ref [] in
diff --git a/compiler/ml/typedecl.ml b/compiler/ml/typedecl.ml
index 070968b337..25af79d146 100644
--- a/compiler/ml/typedecl.ml
+++ b/compiler/ml/typedecl.ml
@@ -630,16 +630,12 @@ let transl_declaration ~type_record_as_object env sdecl id =
       match lbls_opt with
       | Some (lbls, lbls') ->
         check_duplicates sdecl.ptype_loc lbls StringSet.empty;
-        let optional_labels =
-          Ext_list.filter_map lbls (fun lbl ->
-              if lbl.ld_optional then Some lbl.ld_name.txt else None)
-        in
+        let optional = Ext_list.exists lbls (fun lbl -> lbl.ld_optional) in
         ( Ttype_record lbls,
           Type_record
             ( lbls',
               if unbox then Record_unboxed false
-              else if optional_labels <> [] then
-                Record_optional_labels optional_labels
+              else if optional then Record_regular
               else Record_regular ),
           sdecl )
       | None ->
diff --git a/compiler/ml/types.ml b/compiler/ml/types.ml
index e31bdab72f..5b14935bc3 100644
--- a/compiler/ml/types.ml
+++ b/compiler/ml/types.ml
@@ -153,11 +153,9 @@ and record_representation =
       tag: int;
       name: string;
       num_nonconsts: int;
-      optional_labels: string list;
       attrs: Parsetree.attributes;
     }
   | Record_extension (* Inlined record under extension *)
-  | Record_optional_labels of string list (* List of optional labels *)
 
 and label_declaration = {
   ld_id: Ident.t;
@@ -298,6 +296,7 @@ type label_description = {
   lbl_res: type_expr; (* Type of the result *)
   lbl_arg: type_expr; (* Type of the argument *)
   lbl_mut: mutable_flag; (* Is this a mutable field? *)
+  lbl_optional: bool; (* Is this an optional field? *)
   lbl_pos: int; (* Position in block *)
   mutable lbl_all: label_description array;
       (* All the labels in this type. This is mutable only because of a specific feature related to dicts, and should not be mutated elsewhere. *)
@@ -310,16 +309,10 @@ let same_record_representation x y =
   match x with
   | Record_regular -> y = Record_regular
   | Record_float_unused -> y = Record_float_unused
-  | Record_optional_labels lbls -> (
-    match y with
-    | Record_optional_labels lbls2 -> lbls = lbls2
-    | _ -> false)
-  | Record_inlined {tag; name; num_nonconsts; optional_labels} -> (
+  | Record_inlined {tag; name; num_nonconsts} -> (
     match y with
     | Record_inlined y ->
-      tag = y.tag && name = y.name
-      && num_nonconsts = y.num_nonconsts
-      && optional_labels = y.optional_labels
+      tag = y.tag && name = y.name && num_nonconsts = y.num_nonconsts
     | _ -> false)
   | Record_extension -> y = Record_extension
   | Record_unboxed x -> (
diff --git a/compiler/ml/types.mli b/compiler/ml/types.mli
index f8d7addcdb..9f3ac3397a 100644
--- a/compiler/ml/types.mli
+++ b/compiler/ml/types.mli
@@ -281,11 +281,9 @@ and record_representation =
       tag: int;
       name: string;
       num_nonconsts: int;
-      optional_labels: string list;
       attrs: Parsetree.attributes;
     }
   | Record_extension (* Inlined record under extension *)
-  | Record_optional_labels of string list (* List of optional labels *)
 
 and label_declaration = {
   ld_id: Ident.t;
@@ -423,6 +421,7 @@ type label_description = {
   lbl_res: type_expr; (* Type of the result *)
   lbl_arg: type_expr; (* Type of the argument *)
   lbl_mut: mutable_flag; (* Is this a mutable field? *)
+  lbl_optional: bool; (* Is this an optional field? *)
   lbl_pos: int; (* Position in block *)
   mutable lbl_all: label_description array;
   (* All the labels in this type. This is mutable only because of a specific feature related to dicts, and should not be mutated elsewhere. *)
diff --git a/tests/build_tests/super_errors/expected/OptionalImplIntf.res.expected b/tests/build_tests/super_errors/expected/OptionalImplIntf.res.expected
new file mode 100644
index 0000000000..550812989f
--- /dev/null
+++ b/tests/build_tests/super_errors/expected/OptionalImplIntf.res.expected
@@ -0,0 +1,29 @@
+
+  We've found a bug for you!
+  /.../fixtures/OptionalImplIntf.res:3:5-5:1
+
+  1 │ module M: {
+  2 │   type t = {x?: int}
+  3 │ } = {
+  4 │   type t = {x: int}
+  5 │ }
+  6 │ 
+
+  Signature mismatch:
+  Modules do not match:
+    {
+  type t = {x: int}
+}
+  is not included in
+    {
+  type t = {x?: int}
+}
+  Type declarations do not match:
+    type t = {x: int}
+  is not included in
+    type t = {x?: int}
+  /.../fixtures/OptionalImplIntf.res:2:3-20:
+    Expected declaration
+  /.../fixtures/OptionalImplIntf.res:4:3-19:
+    Actual declaration
+  The optional attribute of field x is different.
\ No newline at end of file
diff --git a/tests/build_tests/super_errors/expected/OptionalInlineImplIntf.res.expected b/tests/build_tests/super_errors/expected/OptionalInlineImplIntf.res.expected
new file mode 100644
index 0000000000..32e03447c6
--- /dev/null
+++ b/tests/build_tests/super_errors/expected/OptionalInlineImplIntf.res.expected
@@ -0,0 +1,29 @@
+
+  We've found a bug for you!
+  /.../fixtures/OptionalInlineImplIntf.res:3:5-5:1
+
+  1 │ module M: {
+  2 │   type t = A({x?: int})
+  3 │ } = {
+  4 │   type t = A({x: int})
+  5 │ }
+  6 │ 
+
+  Signature mismatch:
+  Modules do not match:
+    {
+  type t = A({x: int})
+}
+  is not included in
+    {
+  type t = A({x?: int})
+}
+  Type declarations do not match:
+    type t = A({x: int})
+  is not included in
+    type t = A({x?: int})
+  /.../fixtures/OptionalInlineImplIntf.res:2:3-23:
+    Expected declaration
+  /.../fixtures/OptionalInlineImplIntf.res:4:3-22:
+    Actual declaration
+  The optional attribute of field x is different.
\ No newline at end of file
diff --git a/tests/build_tests/super_errors/fixtures/OptionalImplIntf.res b/tests/build_tests/super_errors/fixtures/OptionalImplIntf.res
new file mode 100644
index 0000000000..ed5206a555
--- /dev/null
+++ b/tests/build_tests/super_errors/fixtures/OptionalImplIntf.res
@@ -0,0 +1,5 @@
+module M: {
+  type t = {x?: int}
+} = {
+  type t = {x: int}
+}
diff --git a/tests/build_tests/super_errors/fixtures/OptionalInlineImplIntf.res b/tests/build_tests/super_errors/fixtures/OptionalInlineImplIntf.res
new file mode 100644
index 0000000000..b2927829aa
--- /dev/null
+++ b/tests/build_tests/super_errors/fixtures/OptionalInlineImplIntf.res
@@ -0,0 +1,5 @@
+module M: {
+  type t = A({x?: int})
+} = {
+  type t = A({x: int})
+}
diff --git a/tests/tests/src/record_regression.mjs b/tests/tests/src/record_regression.mjs
index f936ef2908..e939411629 100644
--- a/tests/tests/src/record_regression.mjs
+++ b/tests/tests/src/record_regression.mjs
@@ -55,7 +55,8 @@ newrecord$4.aa = undefined;
 
 function setAA(ao) {
   return {
-    aa: ao
+    aa: ao,
+    bb: undefined
   };
 }