diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/inObjectTest.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/inObjectTest.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+function inObjectTest() {
+    var o = {p: 1, q: 2, r: 3, s: 4, t: 5};
+    var r = 0;
+    for (var i in o) {
+        if (!(i in o))
+            break;
+        if ((i + i) in o)
+            break;
+        ++r;
+    }
+    return r;
+}
+assertEq(inObjectTest(), 5);