[es6] early error when Identifier is an escaped reserved word

src/scanner.cc

 // Copyright 2011 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.
 
 // Features shared by parsing and pre-parsing scanners.
 
 #include "src/scanner.h"
 
 #include <stdint.h>
 
@@ skipping 1481 matching lines @@
 void Scanner::CopyTokenDesc(TokenDesc* to, TokenDesc* from) {
   DCHECK_NOT_NULL(to);
   DCHECK_NOT_NULL(from);
   to->token = from->token;
   to->location = from->location;
   to->literal_chars->CopyFrom(from->literal_chars);
   to->raw_literal_chars->CopyFrom(from->raw_literal_chars);
 }
 
 
+bool Scanner::IsNextEscapedReservedWord(LanguageMode language_mode,
+                                        bool is_generator) {
+  if (next_.token == Token::IDENTIFIER && next_.literal_chars->is_one_byte() &&
+      next_literal_contains_escapes()) {
+    Vector<const uint8_t> chars = next_.literal_chars->one_byte_literal();
+    switch (KeywordOrIdentifierToken(chars.start(), chars.length())) {
+      case Token::IDENTIFIER:
+        return false;
+      case Token::LET:
+      case Token::FUTURE_STRICT_RESERVED_WORD:
+        return is_strict(language_mode);
+      case Token::YIELD:
+        return is_generator || is_strict(language_mode);

[caitp (gmail), 2015/11/04 05:03:37]

yield is reserved in strict mode, so the change was needed

+      default:
+        return true;
+    }
+  }
+  return false;
+}
+
+
 int DuplicateFinder::AddOneByteSymbol(Vector<const uint8_t> key, int value) {
   return AddSymbol(key, true, value);
 }
 
 
 int DuplicateFinder::AddTwoByteSymbol(Vector<const uint16_t> key, int value) {
   return AddSymbol(Vector<const uint8_t>::cast(key), false, value);
 }
 
 
@@ skipping 121 matching lines @@
     backing_store_.Add(static_cast<uint8_t>((one_byte_length >> 7) | 0x80u));
   }
   backing_store_.Add(static_cast<uint8_t>(one_byte_length & 0x7f));
 
   backing_store_.AddBlock(bytes);
   return backing_store_.EndSequence().start();
 }
 
 }  // namespace internal
 }  // namespace v8