[es6] silence access-check failure for well-known symbol properties

test/cctest/test-api.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 21845 matching lines @@
   timeout_thread.Join();
 }
 
 
 TEST(EstimatedContextSize) {
   v8::Isolate* isolate = CcTest::isolate();
   v8::HandleScope scope(isolate);
   LocalContext env;
   CHECK(50000 < env->EstimatedSize());
 }
+
+
+TEST(AccessCheckedIsConcatSpreadable) {
+  i::FLAG_harmony_concat_spreadable = true;
+  v8::Isolate* isolate = CcTest::isolate();
+  HandleScope scope(isolate);
+  LocalContext env;
+
+  // Object with access check
+  Local<ObjectTemplate> spreadable_template = v8::ObjectTemplate::New(isolate);
+  spreadable_template->SetAccessCheckCallbacks(AccessBlocker, nullptr);
+  spreadable_template->Set(v8::Symbol::GetIsConcatSpreadable(isolate),
+                           v8::Boolean::New(isolate, true));
+  Local<Object> object = spreadable_template->NewInstance();
+
+  allowed_access = true;
+  env->Global()->Set(v8_str("object"), object);
+  object->Set(v8_str("length"), v8_num(2));
+  object->Set(0U, v8_str("a"));
+  object->Set(1U, v8_str("b"));
+
+  // Access check is allowed, and the object is spread
+  CompileRun("var result = [].concat(object)");
+  ExpectTrue("Array.isArray(result)");
+  ExpectString("result[0]", "a");
+  ExpectString("result[1]", "b");
+  ExpectTrue("result.length === 2");
+
+  // If access check fails, the value of @@isConcatSpreadable is ignored
+  allowed_access = false;
+  CompileRun("var result = [].concat(object)");
+  ExpectTrue("Array.isArray(result)");
+  ExpectTrue("result[0] === object");
+  ExpectTrue("result.length === 1");
+}