diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/arguments/testDelArg2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/arguments/testDelArg2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+function f(del) {
+    o = arguments;
+    if (del)
+        delete o[2];
+    for (var i = 0; i < 10; ++i)
+        assertEq(o[2] == undefined, del);
+}
+
+// record without arg deleted
+f(false, 1,2,3,4);
+
+// run with arg deleted
+f(true, 1,2,3,4);