diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8/extensions/regress-422269.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8/extensions/regress-422269.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//-----------------------------------------------------------------------------
+var BUGNUMBER = 422269;
+var summary = 'Compile-time let block should not capture runtime references';
+var actual = 'referenced only by stack and closure';
+var expect = 'referenced only by stack and closure';
+
+
+//-----------------------------------------------------------------------------
+test();
+
+//-----------------------------------------------------------------------------
+
+function test()
+{
+  enterFunc ('test');
+  printBugNumber(BUGNUMBER);
+  printStatus (summary);
+
+  function f()
+  {
+    let m = {sin: Math.sin};
+    (function holder() { m.sin(1); })();
+    return m;
+  }
+
+  if (typeof findReferences == 'undefined')
+  {
+    expect = actual = 'Test skipped';
+    print('Test skipped. Requires findReferences function.');
+  }
+  else
+  {
+    var x = f();
+    var refs = findReferences(x);
+
+    // At this point, x should only be referenced from the stack --- the
+    // variable 'x' itself, and any random things the conservative scanner
+    // finds --- and possibly from the 'holder' closure, which could itself
+    // be held alive for random reasons. Remove those from the refs list, and 
+    // then complain if anything is left.
+    for (var edge in refs) {
+      // Remove references from roots, like the stack.
+      if (refs[edge].every(function (r) r === null))
+        delete refs[edge];
+      // Remove references from the closure, which could be held alive for
+      // random reasons.
+      else if (refs[edge].length === 1 &&
+               typeof refs[edge][0] === "function" &&
+               refs[edge][0].name === "holder")
+        delete refs[edge];
+    }
+
+    if (Object.keys(refs).length != 0)
+        actual = "unexpected references to the result of f: " + Object.keys(refs).join(", ");
+  }
+  reportCompare(expect, actual, summary);
+
+  exitFunc ('test');
+}