[esnext] implement frontend changes for async/await proposal

test/cctest/test-parsing.cc

Index: test/cctest/test-parsing.cc
diff --git a/test/cctest/test-parsing.cc b/test/cctest/test-parsing.cc
index 1b0ced08edc3d895d20c7570a3d466de3e3ae048..57535897ca28fd8763b49e729684d4c4318fdc92 100644
--- a/test/cctest/test-parsing.cc
+++ b/test/cctest/test-parsing.cc
@@ -1508,7 +1508,8 @@ enum ParserFlag {
   kAllowHarmonyNewTarget,
   kAllowHarmonyFunctionSent,
   kAllowHarmonyRestrictiveDeclarations,
-  kAllowHarmonyExponentiationOperator
+  kAllowHarmonyExponentiationOperator,
+  kAllowHarmonyAsyncAwait
 };
 
 enum ParserSyncTestResult {
@@ -1528,6 +1529,8 @@ void SetParserFlags(i::ParserBase<Traits>* parser,
       flags.Contains(kAllowHarmonyRestrictiveDeclarations));
   parser->set_allow_harmony_exponentiation_operator(
       flags.Contains(kAllowHarmonyExponentiationOperator));
+  parser->set_allow_harmony_async_await(
+      flags.Contains(kAllowHarmonyAsyncAwait));
 }
 
 
@@ -7230,3 +7233,94 @@ TEST(ExponentiationOperatorErrors) {
   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));
+}