do not inject global open into the file being globally opened (#6483)

Author: zth

jscomp/core/js_implementation.ml

@@ -64,7 +64,7 @@ let after_parsing_sig ppf outputprefix ast =
     else
       let modulename = module_of_filename outputprefix in
       Lam_compile_env.reset ();
-      let initial_env = Res_compmisc.initial_env () in
+      let initial_env = Res_compmisc.initial_env ~modulename () in
       Env.set_unit_name modulename;
       let tsg = Typemod.transl_signature initial_env ast in
       if !Clflags.dump_typedtree then
@@ -149,7 +149,7 @@ let after_parsing_impl ppf outputprefix (ast : Parsetree.structure) =
     else
       let modulename = Ext_filename.module_name outputprefix in
       Lam_compile_env.reset ();
-      let env = Res_compmisc.initial_env () in
+      let env = Res_compmisc.initial_env ~modulename () in
       Env.set_unit_name modulename;
       let typedtree, coercion, _, _ =
         Typemod.type_implementation_more

jscomp/core/res_compmisc.ml

@@ -41,8 +41,13 @@ let open_implicit_module m env =
   in
   snd (Typemod.type_open_ Override env lid.loc lid)
 
-let initial_env () =
+let initial_env ?(modulename) () =
   Ident.reinit ();
+  let open_modules = (match modulename with 
+  | None -> !Clflags.open_modules 
+  | Some modulename -> 
+    !Clflags.open_modules |> List.filter(fun m -> m <> modulename)
+  ) in
   let initial = Env.initial_safe_string in
   let env =
     if !Clflags.nopervasives then initial
@@ -51,4 +56,4 @@ let initial_env () =
   List.fold_left
     (fun env m -> open_implicit_module m env)
     env
-    (List.rev !Clflags.open_modules)
+    (List.rev open_modules)

jscomp/core/res_compmisc.mli

@@ -24,4 +24,4 @@
 
 val init_path : unit -> unit
 
-val initial_env : unit -> Env.t
+val initial_env : ?modulename : string -> unit -> Env.t