[esnext] implement frontend changes for async/await proposal

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 1490 matching lines @@
   data.Dispose();
   return i::MessageTemplate::FormatMessage(isolate, message, arg_object);
 }
 
 enum ParserFlag {
   kAllowLazy,
   kAllowNatives,
   kAllowHarmonyNewTarget,
   kAllowHarmonyFunctionSent,
   kAllowHarmonyRestrictiveDeclarations,
-  kAllowHarmonyExponentiationOperator
+  kAllowHarmonyExponentiationOperator,
+  kAllowHarmonyAsyncAwait
 };
 
 enum ParserSyncTestResult {
   kSuccessOrError,
   kSuccess,
   kError
 };
 
 template <typename Traits>
 void SetParserFlags(i::ParserBase<Traits>* parser,
                     i::EnumSet<ParserFlag> flags) {
   parser->set_allow_lazy(flags.Contains(kAllowLazy));
   parser->set_allow_natives(flags.Contains(kAllowNatives));
   parser->set_allow_harmony_function_sent(
       flags.Contains(kAllowHarmonyFunctionSent));
   parser->set_allow_harmony_restrictive_declarations(
       flags.Contains(kAllowHarmonyRestrictiveDeclarations));
   parser->set_allow_harmony_exponentiation_operator(
       flags.Contains(kAllowHarmonyExponentiationOperator));
+  parser->set_allow_harmony_async_await(
+      flags.Contains(kAllowHarmonyAsyncAwait));
 }
 
 
 void TestParserSyncWithFlags(i::Handle<i::String> source,
                              i::EnumSet<ParserFlag> flags,
                              ParserSyncTestResult result,
                              bool is_module = false) {
   i::Isolate* isolate = CcTest::i_isolate();
   i::Factory* factory = isolate->factory();
 
@@ skipping 5682 matching lines @@
     // "Array() **= 10",
     NULL
   };
   // clang-format on
 
   static const ParserFlag always_flags[] = {
       kAllowHarmonyExponentiationOperator};
   RunParserSyncTest(context_data, error_data, kError, NULL, 0, always_flags,
                     arraysize(always_flags));
 }
+
+
+TEST(AsyncAwait) {
+  // clang-format off
+  const char* context_data[][2] = {
+    { "'use strict';", "" },
+    { "", "" },
+    { NULL, NULL }
+  };
+
+  const char* data[] = {
+    "var asyncFn = async function() {};",
+    "var asyncFn = async function withName() {};",
+    "var asyncFn = async () => 'test';",
+    "var asyncFn = async x => x + 'test';",
+    "async function asyncFn() {}",
+    "var O = { async method() {} }",
+    "var O = { async ['meth' + 'od']() {} }",
+    "var O = { async 'method'() {} }",
+    "var O = { async 0() {} }",
+    "var async\nfunction await() {}",
+    NULL
+  };
+  // clang-format on
+
+  static const ParserFlag always_flags[] = { kAllowHarmonyAsyncAwait };
+  RunParserSyncTest(context_data, data, kSuccess, NULL, 0, always_flags,
+                    arraysize(always_flags));
+}
+
+
+TEST(AsyncAwaitErrors) {
+  // clang-format off
+  const char* context_data[][2] = {
+    { "'use strict';", "" },
+    { "", "" },
+    { NULL, NULL }
+  };
+
+  const char* strict_context_data[][2] = {
+    { "'use strict';", "" },
+    { NULL, NULL }
+  };
+
+  const char* error_data[] = {
+    "var asyncFn = async function() { var await = 1; };",
+    "var asyncFn = async function() { var { await } = 1; };",
+    "var asyncFn = async function() { var [ await ] = 1; };",
+    "var asyncFn = async function await() {};",
+    "var asyncFn = async () => var await = 'test';",
+    "var asyncFn = async await => await + 'test';",
+    "var asyncFn = async function(await) {};",
+    "var asyncFn = async function() { return async (await) => {}; }",
+    "var asyncFn = async (await) => 'test';",
+    "var asyncFn = async x => { var await = 1; }",
+    "var asyncFn = async x => { var { await } = 1; }",
+    "var asyncFn = async x => { var [ await ] = 1; }",
+    "async function f(await) {}",
+    "async function f() { var await = 1; }",
+    "async function f() { var { await } = 1; }",
+    "async function f() { var [ await ] = 1; }",
+
+    "var O = { async method(a, a) {} }",
+    "var O = { async ['meth' + 'od'](a, a) {} }",
+    "var O = { async 'method'(a, a) {} }",
+    "var O = { async 0(a, a) {} }",
+
+    "async function f() { var O = { async [await](a, a) {} } }",
+    NULL
+  };
+
+  const char* strict_error_data[] = {
+    "var O = { async method(eval) {} }",
+    "var O = { async ['meth' + 'od'](eval) {} }",
+    "var O = { async 'method'(eval) {} }",
+    "var O = { async 0(eval) {} }",
+
+    "var O = { async method(arguments) {} }",
+    "var O = { async ['meth' + 'od'](arguments) {} }",
+    "var O = { async 'method'(arguments) {} }",
+    "var O = { async 0(arguments) {} }",
+    NULL
+  };
+  // clang-format on
+
+  static const ParserFlag always_flags[] = { kAllowHarmonyAsyncAwait };
+  RunParserSyncTest(context_data, error_data, kError, NULL, 0, always_flags,
+                    arraysize(always_flags));
+  RunParserSyncTest(strict_context_data, strict_error_data, kError, NULL, 0,
+                    always_flags, arraysize(always_flags));
+}