diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/for-of/manual-advance.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/for-of/manual-advance.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,15 @@
+// Manually advancing the iterator.
+
+load(libdir + 'iteration.js');
+
+function* g(n) { for (var i=0; i<n; i++) yield i; }
+
+var inner = g(20);
+
+var n = 0;
+for (var x of inner) {
+    assertEq(x, n * 2);
+    assertIteratorNext(inner, n * 2 + 1);
+    n++;
+}
+assertEq(n, 10);