Disallow 'yield' in async arrow parameter lists inside generators

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 7667 matching lines @@
     "var asyncFn = async x => await x + 'test';",
     "async function asyncFn() { await 1; }",
     "var O = { async method() { await 1; } }",
     "var O = { async ['meth' + 'od']() { await 1; } }",
     "var O = { async 'method'() { await 1; } }",
     "var O = { async 0() { await 1; } }",
     "async function await() {}",
 
     "var asyncFn = async({ foo = 1 }) => foo;",
     "var asyncFn = async({ foo = 1 } = {}) => foo;",
+
+    "function* g() { var f = async(yield); }",
+    "function* g() { var f = async(x = yield); }",
     NULL
   };
   // clang-format on
 
   static const ParserFlag always_flags[] = {kAllowHarmonyAsyncAwait};
   RunParserSyncTest(context_data, data, kSuccess, NULL, 0, always_flags,
                     arraysize(always_flags));
 
   // clang-format off
   const char* async_body_context_data[][2] = {
@@ skipping 87 matching lines @@
     "var O = { async *method() {} };",
     "var O = { async method*() {} };",
 
     "var asyncFn = async function(x = await 1) { return x; }",
     "async function f(x = await 1) { return x; }",
     "var f = async(x = await 1) => x;",
     "var O = { async method(x = await 1) { return x; } };",
 
     "var f = async(x = await) => 1;",
 
+    "function* g() { var f = async yield => 1; }",
+    "function* g() { var f = async(yield) => 1; }",
+    "function* g() { var f = async(x = yield) => 1; }",
+    "function* g() { var f = async({x = yield}) => 1; }",
+
     "class C { async constructor() {} }",
     "class C {}; class C2 extends C { async constructor() {} }",
     "class C { static async prototype() {} }",
     "class C {}; class C2 extends C { static async prototype() {} }",
 
     "var f = async() => ((async(x = await 1) => x)();",
 
     // Henrique Ferreiro's bug (tm)
     "(async function foo1() { } foo2 => 1)",
     "(async function foo3() { } () => 1)",
@@ skipping 338 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));
 }