diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-iterator-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-iterator-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+// for-of can be used to iterate over a Map twice.
+
+var map = Map([['a', 0], ['b', 1], ['c', 2]]);
+var log = '';
+
+for (let i = 0; i < 2; i++) {
+    for (let [k, v] of map)
+        log += k + v;
+    log += ';'
+}
+assertEq(log, 'a0b1c2;a0b1c2;');