diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/iterator-2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/iterator-2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,12 @@
+// for-of on an empty collection does not execute the loop body or modify the loop variable.
+
+function test(empty) {
+    var x = 'unchanged';
+    for (x of empty)
+        throw fit;
+    assertEq(x, 'unchanged');
+}
+
+test([]);
+test(new Map);
+test(new Set);
\ No newline at end of file