Parse arrow functions at proper precedence level

test/mjsunit/harmony/regress/regress-4211.js

Index: test/mjsunit/harmony/regress/regress-4211.js
diff --git a/test/mjsunit/harmony/regress/regress-4211.js b/test/mjsunit/harmony/regress/regress-4211.js
new file mode 100644
index 0000000000000000000000000000000000000000..8affc7344ac7907b333ed52d1b3b697f1ea2b1ed
--- /dev/null
+++ b/test/mjsunit/harmony/regress/regress-4211.js
@@ -0,0 +1,12 @@
+// Copyright 2015 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.
+//
+// Flags: --harmony-arrow-functions --harmony-rest-parameters
+
+assertThrows("()=>{}()", SyntaxError);
+assertThrows("x=>{}()", SyntaxError);
+assertThrows("(...x)=>{}()", SyntaxError);
+assertThrows("(x)=>{}()", SyntaxError);
+assertThrows("(x,y)=>{}()", SyntaxError);
+assertThrows("(x,y,...z)=>{}()", SyntaxError);