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

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index 74e11b1d454b3b33a3f6bcadb18f91476a246f37..57c051f9ce89a518ae2ba08b5b67ff05903648c2 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -155,6 +155,13 @@ PreParserExpression PreParserTraits::ParseClassLiteral(
 }
 
 
+#define CHECK_OK  ok);                   \
+  if (!*ok) return Statement::Default(); \
+  ((void)0
+#define DUMMY )  // to make indentation work
+#undef DUMMY
+
+
 // Preparsing checks a JavaScript program and emits preparse-data that helps
 // a later parsing to be faster.
 // See preparser-data.h for the data.
@@ -202,6 +209,9 @@ PreParser::Statement PreParser::ParseStatementListItem(bool* ok) {
         return ParseVariableStatement(kStatementListItem, ok);
       }
       break;
+    case Token::IDENTIFIER:
+      CheckNextEscapedKeyword(CHECK_OK);
+      break;
     default:
       break;
   }
@@ -304,13 +314,6 @@ void PreParser::ParseStatementList(int end_token, bool* ok,
 }
 
 
-#define CHECK_OK  ok);                   \
-  if (!*ok) return Statement::Default();  \
-  ((void)0
-#define DUMMY )  // to make indentation work
-#undef DUMMY
-
-
 PreParser::Statement PreParser::ParseStatement(bool* ok) {
   // Statement ::
   //   EmptyStatement