Fix classifier related bug

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index 65c15727724b0d480e44e967ef175fff9c3837fc..2cf04fa568a73fadcdc0cef3c4c8a1f8a105140e 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -1676,11 +1676,14 @@ typename ParserBase<Traits>::ExpressionT ParserBase<Traits>::ParseExpression(
   //   AssignmentExpression
   //   Expression ',' AssignmentExpression
 
-  ExpressionClassifier binding_classifier(this);
-  ExpressionT result =
-      this->ParseAssignmentExpression(accept_IN, &binding_classifier, CHECK_OK);
-  classifier->Accumulate(&binding_classifier,
-                         ExpressionClassifier::AllProductions);
+  ExpressionT result = this->EmptyExpression();
+  {
+    ExpressionClassifier binding_classifier(this);
+    result = this->ParseAssignmentExpression(accept_IN, &binding_classifier,
+                                             CHECK_OK);
+    classifier->Accumulate(&binding_classifier,
+                           ExpressionClassifier::AllProductions);
+  }
   bool is_simple_parameter_list = this->IsIdentifier(result);
   bool seen_rest = false;
   while (peek() == Token::COMMA) {
@@ -3343,7 +3346,6 @@ ParserBase<Traits>::ParseArrowFunctionLiteral(
     } else {
       // Single-expression body
       int pos = position();
-      ExpressionClassifier classifier(this);
       DCHECK(ReturnExprContext::kInsideValidBlock ==
              function_state_->return_expr_context());
       ReturnExprScope allow_tail_calls(
@@ -3351,6 +3353,7 @@ ParserBase<Traits>::ParseArrowFunctionLiteral(
       body = this->NewStatementList(1, zone());
       this->AddParameterInitializationBlock(formal_parameters, body, is_async,
                                             CHECK_OK);
+      ExpressionClassifier classifier(this);

[nickie, 2016/06/21 08:13:24]

(Copying commend from previous PS.)  This change was irrelevant to the bug.  The
classifier is used for parsing in 3358 and 3363.  It is not necessary if 3354
fails at CHECK_OK.

       if (is_async) {
         this->ParseAsyncArrowSingleExpressionBody(body, accept_IN, &classifier,
                                                   pos, CHECK_OK);