diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_5/Regress/regress-170193.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_5/Regress/regress-170193.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,77 @@
+/* -*- 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/. */
+
+/*
+ *
+ * Date:    22 Sep 2002
+ * SUMMARY: adding prop after middle-delete of function w duplicate formal args
+ * See http://bugzilla.mozilla.org/show_bug.cgi?id=170193
+ *
+ */
+//-----------------------------------------------------------------------------
+var UBound = 0;
+var BUGNUMBER = 170193;
+var summary = 'adding property after middle-delete of function w duplicate formal args';
+var status = '';
+var statusitems = [];
+var actual = '';
+var actualvalues = [];
+var expect= '';
+var expectedvalues = [];
+
+/*
+ * This sequence of steps used to cause the SpiderMonkey shell to hang -
+ */
+function f(a,a,b){}
+f.c=42;
+f.d=43;
+delete f.c;  // "middle delete"
+f.e=44;
+
+status = inSection(1);
+actual = f.c;
+expect = undefined;
+addThis();
+
+status = inSection(2);
+actual = f.d;
+expect = 43;
+addThis();
+
+status = inSection(3);
+actual = f.e;
+expect = 44;
+addThis();
+
+
+
+//-----------------------------------------------------------------------------
+test();
+//-----------------------------------------------------------------------------
+
+
+
+function addThis()
+{
+  statusitems[UBound] = status;
+  actualvalues[UBound] = actual;
+  expectedvalues[UBound] = expect;
+  UBound++;
+}
+
+
+function test()
+{
+  enterFunc('test');
+  printBugNumber(BUGNUMBER);
+  printStatus(summary);
+
+  for (var i=0; i<UBound; i++)
+  {
+    reportCompare(expectedvalues[i], actualvalues[i], statusitems[i]);
+  }
+
+  exitFunc ('test');
+}