diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testInnerTreeMutatingUpvars.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testInnerTreeMutatingUpvars.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+function f() {
+    for (var a = 0; a < 8; ++a) {
+        (function () {
+            var x;
+            for (var b = 0; b < 8; ++b) {
+                x = 0;
+                (function () {
+                    for (var i = 0; i < 1; ++i) {
+                        x = 1;
+                    }
+                })();
+                x++;
+            }
+        })();
+    }
+}
+f();