Use value from as attribute if available

Author: shulhi

jscomp/core/lam_constant_convert.ml

@@ -50,6 +50,9 @@ let rec convert_constant (const : Lambda.structured_constant) : Lam_constant.t =
           Const_int { i = Int32.of_int i; comment = Pt_assertfalse }
       | Pt_constructor { name; const; non_const; attrs } ->
           let tag_type = Ast_untagged_variants.process_tag_type attrs in
+          let i = match tag_type with
+            | Some(Ast_untagged_variants.Int(v)) -> v
+            | _ -> i in
           Const_int
             {
               i = Int32.of_int i;