Use dedicated syntax for dotdotdot.

Author: cristianoc

jscomp/test/DotDotDot.res

@@ -1,14 +1,14 @@
 type a = {x: int}
 
-type b = {\"...": a, y: string}
+type b = {...a, y: string}
 
-type c = {\"...": b, z: string}
+type c = {...b, z: string}
 
 let v: c = {x: 10, y: "", z: ""}
 
 type vw = {v: float, w: float}
 
-type cvw = {\"...": c, \"...": vw}
+type cvw = {...c, ...vw}
 
 let v2: cvw = {x: 10, y: "", z: "", v: 1.0, w: 2.0}
 
@@ -30,14 +30,14 @@ type anchorProps = {
 type divProps = {\"...": globalProps}
 
 type svgProps = {
-  \"...": globalProps,
+  ...globalProps,
   x?: string,
   y?: string,
 }
 
 module MultipleDotDotDots = {
   type t1 = {x: int}
   type t2 = {y: string}
-  type t = {\"...": t1, \"...": t2}
+  type t = {...t1, ...t2}
   let x: t = {x: 10, y: "abc"}
 }

res_syntax/src/res_core.ml

@@ -146,9 +146,6 @@ module ErrorMessages = struct
     "An inline record type declaration is only allowed in a variant \
      constructor's declaration"
 
-  let sameTypeSpread =
-    "You're using a ... spread without extra fields. This is the same type."
-
   let polyVarIntWithSuffix number =
     "A numeric polymorphic variant cannot be followed by a letter. Did you \
      mean `#" ^ number ^ "`?"
@@ -4094,19 +4091,10 @@ and parseRecordOrObjectType ~attrs p =
         (Diagnostics.message ErrorMessages.forbiddenInlineRecordDeclaration)
     | _ -> ()
   in
-  let startFirstField = p.startPos in
   let fields =
     parseCommaDelimitedRegion ~grammar:Grammar.StringFieldDeclarations
       ~closing:Rbrace ~f:parseStringFieldDeclaration p
   in
-  let () =
-    match fields with
-    | [Parsetree.Oinherit {ptyp_loc}] ->
-      (* {...x}, spread without extra fields *)
-      Parser.err p ~startPos:startFirstField ~endPos:ptyp_loc.loc_end
-        (Diagnostics.message ErrorMessages.sameTypeSpread)
-    | _ -> ()
-  in
   Parser.expect Rbrace p;
   let loc = mkLoc startPos p.prevEndPos in
   Ast_helper.Typ.object_ ~loc ~attrs fields closedFlag
@@ -4566,8 +4554,6 @@ and parseConstrDeclArgs p =
             match p.token with
             | Rbrace ->
               (* {...x}, spread without extra fields *)
-              Parser.err ~startPos:dotdotdotStart ~endPos:dotdotdotEnd p
-                (Diagnostics.message ErrorMessages.sameTypeSpread);
               Parser.next p
             | _ -> Parser.expect Comma p
           in
@@ -4993,8 +4979,6 @@ and parseRecordOrObjectDecl p =
       match p.token with
       | Rbrace ->
         (* {...x}, spread without extra fields *)
-        Parser.err ~startPos:dotdotdotStart ~endPos:dotdotdotEnd p
-          (Diagnostics.message ErrorMessages.sameTypeSpread);
         Parser.next p
       | _ -> Parser.expect Comma p
     in