Disallow 'await' in object literal shorthand position

Also lots of cleanup around the checking for 'await' as an identifier
throughout the parser and preparser.

R=caitp@igalia.com, littledan@chromium.org
BUG=v8:4483,v8:5298

Review-Url: https://codereview.chromium.org/2267493002
Cr-Commit-Position: refs/heads/master@{#38798}

src/parsing/parser.cc

@@ -313,10 +313,6 @@ bool ParserTraits::IsUndefined(const AstRawString* identifier) const {
   return identifier == parser_->ast_value_factory()->undefined_string();
 }
 
-bool ParserTraits::IsAwait(const AstRawString* identifier) const {
-  return identifier == parser_->ast_value_factory()->await_string();
-}
-
 bool ParserTraits::IsPrototype(const AstRawString* identifier) const {
   return identifier == parser_->ast_value_factory()->prototype_string();
 }
@@ -2090,13 +2086,6 @@ Statement* Parser::ParseHoistableDeclaration(
     variable_name = name;
   }
 
-  if (V8_UNLIKELY(is_async_function() && this->IsAwait(name))) {
-    ReportMessageAt(scanner()->location(),
-                    MessageTemplate::kAwaitBindingIdentifier);
-    *ok = false;
-    return nullptr;
-  }
-
   FuncNameInferrer::State fni_state(fni_);
   if (fni_ != NULL) fni_->PushEnclosingName(name);
   FunctionLiteral* fun = ParseFunctionLiteral(
@@ -4401,13 +4390,8 @@ Expression* Parser::ParseAsyncFunctionExpression(bool* ok) {
 
   if (peek_any_identifier()) {
     type = FunctionLiteral::kNamedExpression;
-    name = ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
-    if (this->IsAwait(name)) {
-      ReportMessageAt(scanner()->location(),
-                      MessageTemplate::kAwaitBindingIdentifier);
-      *ok = false;
-      return nullptr;
-    }
+    name = ParseIdentifierOrStrictReservedWord(FunctionKind::kAsyncFunction,
+                                               &is_strict_reserved, CHECK_OK);
   }
   return ParseFunctionLiteral(name, scanner()->location(),
                               is_strict_reserved ? kFunctionNameIsStrictReserved

src/parsing/parser.h

@@ -177,7 +177,6 @@ class ParserTraits {
   bool IsArguments(const AstRawString* identifier) const;
   bool IsEvalOrArguments(const AstRawString* identifier) const;
   bool IsUndefined(const AstRawString* identifier) const;
-  bool IsAwait(const AstRawString* identifier) const;
   V8_INLINE bool IsFutureStrictReserved(const AstRawString* identifier) const;
 
   // Returns true if the expression is of type "this.foo".

src/parsing/preparser.cc

@@ -404,13 +404,6 @@ PreParser::Statement PreParser::ParseHoistableDeclaration(
   Identifier name = ParseIdentifierOrStrictReservedWord(
       &is_strict_reserved, CHECK_OK);
 
-  if (V8_UNLIKELY(is_async_function() && this->IsAwait(name))) {
-    ReportMessageAt(scanner()->location(),
-                    MessageTemplate::kAwaitBindingIdentifier);
-    *ok = false;
-    return Statement::Default();
-  }
-
   ParseFunctionLiteral(name, scanner()->location(),
                        is_strict_reserved ? kFunctionNameIsStrictReserved
                                           : kFunctionNameValidityUnknown,
@@ -1163,13 +1156,8 @@ PreParser::Expression PreParser::ParseAsyncFunctionExpression(bool* ok) {
 
   if (peek_any_identifier()) {
     type = FunctionLiteral::kNamedExpression;
-    name = ParseIdentifierOrStrictReservedWord(&is_strict_reserved, CHECK_OK);
-    if (this->IsAwait(name)) {
-      ReportMessageAt(scanner()->location(),
-                      MessageTemplate::kAwaitBindingIdentifier);
-      *ok = false;
-      return Expression::Default();
-    }
+    name = ParseIdentifierOrStrictReservedWord(FunctionKind::kAsyncFunction,
+                                               &is_strict_reserved, CHECK_OK);
   }
 
   ParseFunctionLiteral(name, scanner()->location(),

src/parsing/token.h

@@ -200,7 +200,7 @@ class Token {
   }
 
   static bool IsIdentifier(Value tok, LanguageMode language_mode,
-                           bool is_generator, bool is_module) {
+                           bool is_generator, bool disallow_await) {
     switch (tok) {
       case IDENTIFIER:
       case ASYNC:
@@ -213,7 +213,7 @@ class Token {
       case YIELD:
         return !is_generator && is_sloppy(language_mode);
       case AWAIT:
-        return !is_module;
+        return !disallow_await;
       default:
         return false;
     }

test/cctest/test-parsing.cc

@@ -7865,6 +7865,8 @@ TEST(AsyncAwaitErrors) {
     "var f = async() => await;",
     "var f = async() => { await; };",
 
+    "async function f() { return {await} }",
+
     "var asyncFn = async function*() {}",
     "async function* f() {}",
     "var O = { *async method() {} };",