Parse arrow functions at proper precedence level

src/parser.cc

 // 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.
 
 #include "src/parser.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/ast-literal-reindexer.h"
 #include "src/bailout-reason.h"
@@ skipping 3951 matching lines @@
   }
 
   AddFormalParameter(parameters, expr, initializer, is_rest);
 }
 
 
 void ParserTraits::ParseArrowFunctionFormalParameterList(
     ParserFormalParameters* parameters, Expression* expr,
     const Scanner::Location& params_loc,
     Scanner::Location* duplicate_loc, bool* ok) {
+  if (expr->IsEmptyParentheses()) return;
+
   ParseArrowFunctionFormalParameters(parameters, expr, params_loc,
                                      duplicate_loc, ok);
   if (!*ok) return;
 
   for (int i = 0; i < parameters->Arity(); ++i) {
     auto parameter = parameters->at(i);
     ExpressionClassifier classifier;
     DeclareFormalParameter(
         parameters->scope, parameter, parameters->is_simple, &classifier);
     if (!duplicate_loc->IsValid()) {
@@ skipping 2125 matching lines @@
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(
       ast_value_factory()->reflect_construct_string(), NULL, args, pos);
 }
 }  // namespace internal
 }  // namespace v8