diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Regress/regress-252892.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Regress/regress-252892.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,65 @@
+/* -*- 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 = 252892;
+var summary = 'for (var i in o) in heavyweight function f should define i in f\'s activation';
+var actual = '';
+var expect = '';
+
+printBugNumber(BUGNUMBER);
+printStatus (summary);
+
+var status; 
+
+var dodis;
+
+function f1(o){for(var x in o)printStatus(o[x]); return x}
+function f2(o){with(this)for(var x in o)printStatus(o[x]); return x}
+function f2novar(o){with(this)for(x in o)printStatus(o[x]); return x}
+function f3(i,o){for(var x=i in o)printStatus(o[x]); return x}
+function f4(i,o){with(this)for(var x=i in o)printStatus(o[x]); return x}
+
+var t=0;
+function assert(c)
+{
+  ++t;
+
+  status = summary + ' ' + inSection(t);
+  expect = true;
+  actual = c;
+
+  if (!c)
+  {
+    printStatus(t + " FAILED!");
+  }
+  reportCompare(expect, actual, summary);
+}
+
+assert(f1([]) == undefined);
+
+assert(f1(['first']) == 0);
+
+assert(f2([]) == undefined);
+
+assert(f2(['first']) == 0);
+
+assert(f3(42, []) == 42);
+
+assert(f3(42, ['first']) == 0);
+
+assert(f4(42, []) == 42);
+
+assert(f4(42, ['first']) == 0);
+
+this.x = 41;
+
+assert(f2([]) == undefined);
+
+assert(f2novar([]) == 41);
+
+assert(f2(['first']) == undefined);
+
+assert(f2novar(['first']) == 0);