diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug722028.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug722028.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+
+gczeal(4);
+var BUGNUMBER = 668024;
+var summary =
+print(BUGNUMBER + ": " + summary);
+var arr = [0, 1, 2, 3, 4, 5, , 7];
+var seen = [];
+for (var p in arr) {
+    if (seen.indexOf(unescape) >= 0) {}
+    arr.splice(2, 3);
+  seen.push(p);
+}
+