[es6] support rest parameters in arrow functions (alternative)

src/preparser.cc

Index: src/preparser.cc
diff --git a/src/preparser.cc b/src/preparser.cc
index e7fff33d3bf7f6d47b96a9debbe5ac7a52c0957f..14e9e4a169e3ebccddd536060a28b9b0a112def2 100644
--- a/src/preparser.cc
+++ b/src/preparser.cc
@@ -988,7 +988,8 @@ PreParserExpression PreParser::ParseClassLiteral(
 
   bool has_extends = Check(Token::EXTENDS);
   if (has_extends) {
-    ParseLeftHandSideExpression(CHECK_OK);
+    const bool maybeArrow = false;
+    ParseLeftHandSideExpression(maybeArrow, CHECK_OK);
   }
 
   ClassLiteralChecker checker(this);