diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/array-iterator-changing.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/array-iterator-changing.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+// Array iterators reflect changes to elements of the underlying array.
+
+load(libdir + "asserts.js");
+load(libdir + "iteration.js");
+
+var arr = [0, 1, 2];
+var it = arr[std_iterator]();
+arr[0] = 1000;
+arr[2] = 2000;
+assertIteratorNext(it, 1000);
+assertIteratorNext(it, 1);
+assertIteratorNext(it, 2000);
+assertIteratorDone(it, undefined);
+
+// test that .keys() and .entries() have the same behaviour
+
+arr = [0, 1, 2];
+var ki = arr.keys();
+var ei = arr.entries();
+arr[0] = 1000;
+arr[2] = 2000;
+assertIteratorNext(ki, 0);
+assertIteratorNext(ei, [0, 1000]);
+assertIteratorNext(ki, 1);
+assertIteratorNext(ei, [1, 1]);
+assertIteratorNext(ki, 2);
+assertIteratorNext(ei, [2, 2000]);
+assertIteratorDone(ki, undefined);
+assertIteratorDone(ei, undefined);