Reland of write scopes of non-simple default arguments

test/mjsunit/regress/regress-616386.js

Index: test/mjsunit/regress/regress-616386.js
diff --git a/test/mjsunit/regress/regress-616386.js b/test/mjsunit/regress/regress-616386.js
new file mode 100644
index 0000000000000000000000000000000000000000..d462ab7509c32724b44a1e5862acd98920d9983a
--- /dev/null
+++ b/test/mjsunit/regress/regress-616386.js
@@ -0,0 +1,10 @@
+// Copyright 2016 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: --no-lazy
+
+assertEquals(0, ((y = (function(a2) { bbbb = a2 }), bbbb = eval('1')) => {y(0); return bbbb})())
+assertEquals(0, (({y = (function(a2) { bbbb = a2 }), bbbb = eval('1')} = {}) => {y(0); return bbbb})())
+assertEquals(0, (function (y = (function(a2) { bbbb = a2 }), bbbb = eval('1')) {y(0); return bbbb})())
+assertEquals(0, (function ({y = (function(a2) { bbbb = a2 }), bbbb = eval('1')} = {}) {y(0); return bbbb})())