diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/generators-2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/generators-2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+// Generator-iterators are consumed the first time they are iterated.
+
+function range(n) {
+    for (var i = 0; i < n; i++)
+        yield i;
+}
+
+var r = range(10);
+var i = 0;
+for (var x in r)
+    assertEq(x, i++);
+assertEq(i, 10);
+for (var y in r)
+    throw "FAIL";
+assertEq(y, undefined);