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

src/parser.h

 // Copyright 2012 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.
 
 #ifndef V8_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // TODO(titzer): remove this include dependency
@@ skipping 799 matching lines @@
   V8_INLINE void AddTemplateSpan(TemplateLiteralState* state, bool tail);
   V8_INLINE void AddTemplateExpression(TemplateLiteralState* state,
                                        Expression* expression);
   V8_INLINE Expression* CloseTemplateLiteral(TemplateLiteralState* state,
                                              int start, Expression* tag);
   V8_INLINE Expression* NoTemplateTag() { return NULL; }
   V8_INLINE static bool IsTaggedTemplate(const Expression* tag) {
     return tag != NULL;
   }
 
+  Expression* SpreadExpression(Expression* node) {
+    return node->AsSpread()->expression();
+  }
+
  private:
   Parser* parser_;
 };
 
 
 class Parser : public ParserBase<ParserTraits> {
  public:
   explicit Parser(ParseInfo* info);
   ~Parser() {
     delete reusable_preparser_;
@@ skipping 298 matching lines @@
 }
 
 
 Expression* ParserTraits::CloseTemplateLiteral(TemplateLiteralState* state,
                                                int start, Expression* tag) {
   return parser_->CloseTemplateLiteral(state, start, tag);
 }
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_