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

src/scanner.cc

Index: src/scanner.cc
diff --git a/src/scanner.cc b/src/scanner.cc
index 04712e9f32a8ea529cc3b02ff6210e4e0d2b6e91..4392951c690ca91c01225bc6c3551ada6007e96a 100644
--- a/src/scanner.cc
+++ b/src/scanner.cc
@@ -1499,6 +1499,27 @@ void Scanner::CopyTokenDesc(TokenDesc* to, TokenDesc* from) {
 }
 
 
+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);
 }