diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug-508061.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug-508061.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+function loop() {
+    var x;
+    for (var i = 0; i < 9; i++)
+        x = {1.5: 1};
+    return x;
+}
+
+loop(); // record
+Object.prototype.__defineSetter__('1.5', function () { return 'BAD'; });
+var x = loop(); // playback
+assertEq(x["1.5"], 1);
\ No newline at end of file