[es6] Fix parsing of 'yield' in function and generator expressions

src/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/bailout-reason.h"
 #include "src/expression-classifier.h"
 #include "src/func-name-inferrer.h"
@@ skipping 646 matching lines @@
 
   // Parses an identifier that is valid for the current scope, in particular it
   // fails on strict mode future reserved keywords in a strict scope. If
   // allow_eval_or_arguments is kAllowEvalOrArguments, we allow "eval" or
   // "arguments" as identifier even in strict mode (this is needed in cases like
   // "var foo = eval;").
   IdentifierT ParseIdentifier(AllowRestrictedIdentifiers, bool* ok);
   IdentifierT ParseAndClassifyIdentifier(ExpressionClassifier* classifier,
                                          bool* ok);
   // Parses an identifier or a strict mode future reserved word, and indicate
-  // whether it is strict mode future reserved.
+  // whether it is strict mode future reserved. Allows passing in is_generator
+  // for the case of parsing the identifier in a function expression, where the
+  // relevant "is_generator" bit is of the function being parsed, not the
+  // containing
+  // function.
+  IdentifierT ParseIdentifierOrStrictReservedWord(bool is_generator,
+                                                  bool* is_strict_reserved,
+                                                  bool* ok);
   IdentifierT ParseIdentifierOrStrictReservedWord(bool* is_strict_reserved,
-                                                  bool* ok);
+                                                  bool* ok) {
+    return ParseIdentifierOrStrictReservedWord(this->is_generator(),
+                                               is_strict_reserved, ok);
+  }
+
   IdentifierT ParseIdentifierName(bool* ok);
   // Parses an identifier and determines whether or not it is 'get' or 'set'.
   IdentifierT ParseIdentifierNameOrGetOrSet(bool* is_get, bool* is_set,
                                             bool* ok);
 
 
   ExpressionT ParseRegExpLiteral(bool seen_equal,
                                  ExpressionClassifier* classifier, bool* ok);
 
   ExpressionT ParsePrimaryExpression(ExpressionClassifier* classifier,
@@ skipping 1459 matching lines @@
     return this->GetSymbol(scanner());
   } else {
     this->ReportUnexpectedToken(next);
     *ok = false;
     return Traits::EmptyIdentifier();
   }
 }
 
 
 template <class Traits>
-typename ParserBase<Traits>::IdentifierT ParserBase<
-    Traits>::ParseIdentifierOrStrictReservedWord(bool* is_strict_reserved,
-                                                 bool* ok) {
+typename ParserBase<Traits>::IdentifierT
+ParserBase<Traits>::ParseIdentifierOrStrictReservedWord(
+    bool is_generator, bool* is_strict_reserved, bool* ok) {
   Token::Value next = Next();
   if (next == Token::IDENTIFIER) {
     *is_strict_reserved = false;
   } else if (next == Token::FUTURE_STRICT_RESERVED_WORD || next == Token::LET ||
-             next == Token::STATIC ||
-             (next == Token::YIELD && !this->is_generator())) {
+             next == Token::STATIC || (next == Token::YIELD && !is_generator)) {
     *is_strict_reserved = true;
   } else {
     ReportUnexpectedToken(next);
     *ok = false;
     return Traits::EmptyIdentifier();
   }
 
   IdentifierT name = this->GetSymbol(scanner());
   if (this->IsArguments(name)) scope_->RecordArgumentsUsage();
   return name;
@@ skipping 1321 matching lines @@
 
     Consume(Token::FUNCTION);
     int function_token_position = position();
     bool is_generator = Check(Token::MUL);
     IdentifierT name = this->EmptyIdentifier();
     bool is_strict_reserved_name = false;
     Scanner::Location function_name_location = Scanner::Location::invalid();
     FunctionLiteral::FunctionType function_type =
         FunctionLiteral::ANONYMOUS_EXPRESSION;
     if (peek_any_identifier()) {
-      name = ParseIdentifierOrStrictReservedWord(&is_strict_reserved_name,
-                                                 CHECK_OK);
+      name = ParseIdentifierOrStrictReservedWord(
+          is_generator, &is_strict_reserved_name, CHECK_OK);
       function_name_location = scanner()->location();
       function_type = FunctionLiteral::NAMED_EXPRESSION;
     }
     result = this->ParseFunctionLiteral(
         name, function_name_location,
         is_strict_reserved_name ? kFunctionNameIsStrictReserved
                                 : kFunctionNameValidityUnknown,
         is_generator ? FunctionKind::kGeneratorFunction
                      : FunctionKind::kNormalFunction,
         function_token_position, function_type, FunctionLiteral::NORMAL_ARITY,
@@ skipping 729 matching lines @@
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PREPARSER_H