Introduce ModuleScope subclass of DeclarationScope

test/cctest/test-parsing.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5964 matching lines @@
       "export {foob};";
   i::Handle<i::String> source = factory->NewStringFromAsciiChecked(kSource);
   i::Handle<i::Script> script = factory->NewScript(source);
   i::Zone zone(CcTest::i_isolate()->allocator());
   i::ParseInfo info(&zone, script);
   i::Parser parser(&info);
   info.set_module();
   CHECK(parser.Parse(&info));
   CHECK(i::Compiler::Analyze(&info));
   i::FunctionLiteral* func = info.literal();
-  i::DeclarationScope* module_scope = func->scope();
+  i::ModuleScope* module_scope = func->scope()->AsModuleScope();
   i::Scope* outer_scope = module_scope->outer_scope();
   CHECK(outer_scope->is_script_scope());
   CHECK_NULL(outer_scope->outer_scope());
   CHECK(module_scope->is_module_scope());
   i::ZoneList<i::Declaration*>* declarations = module_scope->declarations();
   CHECK_EQ(13, declarations->length());
 
   CHECK(declarations->at(0)->proxy()->raw_name()->IsOneByteEqualTo("x"));
   CHECK(declarations->at(0)->proxy()->var()->mode() == i::LET);
   CHECK(declarations->at(0)->proxy()->var()->binding_needs_init());
@@ skipping 2145 matching lines @@
     "(a,);",
     "(a,b,c,);",
     NULL
   };
   // clang-format on
 
   static const ParserFlag always_flags[] = {kAllowHarmonyTrailingCommas};
   RunParserSyncTest(context_data, data, kError, NULL, 0, always_flags,
                     arraysize(always_flags));
 }