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

src/scanner.h

 // 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.
 
 #ifndef V8_SCANNER_H_
 #define V8_SCANNER_H_
 
 #include "src/allocation.h"
@@ skipping 355 matching lines @@
   Location location() const { return current_.location; }
 
   // Similar functions for the upcoming token.
 
   // One token look-ahead (past the token returned by Next()).
   Token::Value peek() const { return next_.token; }
 
   Location peek_location() const { return next_.location; }
 
   bool literal_contains_escapes() const {
-    Location location = current_.location;
-    int source_length = (location.end_pos - location.beg_pos);
-    if (current_.token == Token::STRING) {
-      // Subtract delimiters.
-      source_length -= 2;
-    }
-    return current_.literal_chars->length() != source_length;
+    return LiteralContainsEscapes(current_);
+  }
+  bool next_literal_contains_escapes() const {
+    return LiteralContainsEscapes(next_);
   }
   bool is_literal_contextual_keyword(Vector<const char> keyword) {
     DCHECK_NOT_NULL(current_.literal_chars);
     return current_.literal_chars->is_contextual_keyword(keyword);
   }
   bool is_next_contextual_keyword(Vector<const char> keyword) {
     DCHECK_NOT_NULL(next_.literal_chars);
     return next_.literal_chars->is_contextual_keyword(keyword);
   }
 
@@ skipping 265 matching lines @@
   Token::Value SkipSingleLineComment();
   Token::Value SkipSourceURLComment();
   void TryToParseSourceURLComment();
   Token::Value SkipMultiLineComment();
   // Scans a possible HTML comment -- begins with '<!'.
   Token::Value ScanHtmlComment();
 
   void ScanDecimalDigits();
   Token::Value ScanNumber(bool seen_period);
   Token::Value ScanIdentifierOrKeyword();
-  Token::Value ScanIdentifierSuffix(LiteralScope* literal);
+  Token::Value ScanIdentifierSuffix(LiteralScope* literal, bool escaped);
 
   Token::Value ScanString();
 
   // Scans an escape-sequence which is part of a string and adds the
   // decoded character to the current literal. Returns true if a pattern
   // is scanned.
   template <bool capture_raw, bool in_template_literal>
   bool ScanEscape();
 
   // Decodes a Unicode escape-sequence which is part of an identifier.
   // If the escape sequence cannot be decoded the result is kBadChar.
   uc32 ScanIdentifierUnicodeEscape();
   // Helper for the above functions.
   template <bool capture_raw>
   uc32 ScanUnicodeEscape();
 
   Token::Value ScanTemplateSpan();
 
   // Return the current source position.
   int source_pos() {
     return static_cast<int>(source_->pos()) - kCharacterLookaheadBufferSize;
   }
 
+  static bool LiteralContainsEscapes(const TokenDesc& token) {
+    Location location = token.location;
+    int source_length = (location.end_pos - location.beg_pos);
+    if (token.token == Token::STRING) {
+      // Subtract delimiters.
+      source_length -= 2;
+    }
+    return token.literal_chars->length() != source_length;
+  }
+
   UnicodeCache* unicode_cache_;
 
   // Buffers collecting literal strings, numbers, etc.
   LiteralBuffer literal_buffer0_;
   LiteralBuffer literal_buffer1_;
   LiteralBuffer literal_buffer2_;
 
   // Values parsed from magic comments.
   LiteralBuffer source_url_;
   LiteralBuffer source_mapping_url_;
@@ skipping 54 matching lines @@
   bool has_line_terminator_before_next_;
   // Whether there is a multi-line comment that contains a
   // line-terminator after the current token, and before the next.
   bool has_multiline_comment_before_next_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_SCANNER_H_