diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_5/extensions/bug496985.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_5/extensions/bug496985.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+var a = function() {
+    return function ({x: arguments}) {
+        return arguments;
+    }
+}
+var b = eval(uneval(a));
+
+assertEq(a()({x: 1}), 1);
+assertEq(b()({x: 1}), 1);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);