diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arguments/defaults-with-arguments.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arguments/defaults-with-arguments.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,10 @@
+function f(a=1, b=2, c=3) { return arguments; }
+var args = f();
+assertEq(args.length, 0);
+assertEq("0" in args, false);
+args = f(5, 6);
+assertEq(args.length, 2);
+assertEq(args[1], 6);
+args = f(9, 8, 7, 6, 5);
+assertEq(args.length, 5);
+assertEq(args[4], 5);