diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_5/strict/15.4.5.1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_5/strict/15.4.5.1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,84 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ */
+
+var out = {};
+
+function arr() {
+  return Object.defineProperty([1, 2, 3, 4], 2, {configurable: false});
+}
+
+function nonStrict1(out)
+{
+  var a = out.array = arr();
+  a.length = 2;
+}
+
+function strict1(out)
+{
+  "use strict";
+  var a = out.array = arr();
+  a.length = 2;
+  return a;
+}
+
+out.array = null;
+nonStrict1(out);
+assertEq(deepEqual(out.array, [1, 2, 3]), true);
+
+out.array = null;
+try
+{
+  strict1(out);
+  throw "no error";
+}
+catch (e)
+{
+  assertEq(e instanceof TypeError, true, "expected TypeError, got " + e);
+}
+assertEq(deepEqual(out.array, [1, 2, 3]), true);
+
+// Internally, SpiderMonkey has two representations for arrays:
+// fast-but-inflexible, and slow-but-flexible. Adding a non-index property
+// to an array turns it into the latter. We should test on both kinds.
+function addx(obj) {
+  obj.x = 5;
+  return obj;
+}
+
+function nonStrict2(out)
+{
+  var a = out.array = addx(arr());
+  a.length = 2;
+}
+
+function strict2(out)
+{
+  "use strict";
+  var a = out.array = addx(arr());
+  a.length = 2;
+}
+
+out.array = null;
+nonStrict2(out);
+assertEq(deepEqual(out.array, addx([1, 2, 3])), true);
+
+out.array = null;
+try
+{
+  strict2(out);
+  throw "no error";
+}
+catch (e)
+{
+  assertEq(e instanceof TypeError, true, "expected TypeError, got " + e);
+}
+assertEq(deepEqual(out.array, addx([1, 2, 3])), true);
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
+
+print("Tests complete");