diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-iterator-pairs-3.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-iterator-pairs-3.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+// Modifying an array returned by mapiter.next() does not modify the Map.
+
+load(libdir + "iteration.js");
+
+var map = Map([['a', 1]]);
+var res = map[std_iterator]().next();
+assertIteratorResult(res, ['a', 1], false);
+res.value[0] = 'b';
+res.value[1] = 2;
+assertIteratorResult(res, ['b', 2], false);
+assertEq(map.get('a'), 1);
+assertEq(map.has('b'), false);
+assertEq(map.size, 1);