Record definition spread issues (#6154)

Author: zth

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :bug: Bug Fix
 
 - Fix broken formatting in uncurried mode for functions with _ placeholder args. https://github.com/rescript-lang/rescript-compiler/pull/6148
+- Fix issue where spreading record types with optional labels would not have their labels preserved as optional. https://github.com/rescript-lang/rescript-compiler/pull/6154
 
 # 11.0.0-alpha.3
 

jscomp/ml/typedecl.ml

@@ -439,13 +439,6 @@ let transl_declaration ~typeRecordAsObject env sdecl id =
                 else typ in
               {lbl with  pld_type = typ }) in
           let lbls, lbls' = transl_labels env true lbls in
-          let rep =
-            if unbox then Record_unboxed false
-            else 
-              if optionalLabels <> []
-              then Record_optional_labels optionalLabels
-              else Record_regular
-          in
           let lbls_opt = match lbls, lbls' with
             | {ld_name = {txt = "..."}; ld_type} :: _, _ :: _ ->
               let rec extract t = match t.desc with
@@ -479,7 +472,15 @@ let transl_declaration ~typeRecordAsObject env sdecl id =
           (match lbls_opt with
           | Some (lbls, lbls') ->
             check_duplicates lbls StringSet.empty;
-            Ttype_record lbls, Type_record(lbls', rep), sdecl
+            let optionalLabels =
+              Ext_list.filter_map lbls (fun lbl ->
+                  if has_optional lbl.ld_attributes then Some lbl.ld_name.txt else None)
+            in
+            Ttype_record lbls, Type_record(lbls', if unbox then 
+                Record_unboxed false
+              else if optionalLabels <> [] then 
+                Record_optional_labels optionalLabels
+              else Record_regular), sdecl
           | None ->
              (* Could not find record type decl for ...t: assume t is an object type and this is syntax ambiguity *)
              typeRecordAsObject := true;

jscomp/test/DotDotDot.js

@@ -22,7 +22,13 @@ var v2 = {
   w: 2.0
 };
 
+var x = {
+  name: "test",
+  x: "test"
+};
+
 exports.v = v;
 exports.v2 = v2;
+exports.x = x;
 exports.MultipleDotDotDots = MultipleDotDotDots;
 /* No side effect */

jscomp/test/DotDotDot.res

@@ -35,6 +35,11 @@ type svgProps = {
   y?: string,
 }
 
+let x: svgProps = {x: "test", name: "test"}
+
+// uncomment this to reveal a parser error
+// type copiedSvgProps = {...svgProps}
+
 module MultipleDotDotDots = {
   type t1 = {x: int}
   type t2 = {y: string}