diff -r 000000000000 -r 6474c204b198 js/src/tests/ecma_5/strict/primitive-this-no-writeback.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/ecma_5/strict/primitive-this-no-writeback.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+/* -*- 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/
+ */
+
+/* Verify that GETTHISPROP does not update the frame's |this| slot. */
+
+var f = String.prototype.m = function () {
+    "use strict";
+    assertEq(this, "s");
+    // The GETTHISPROP should not cause |this| to become wrapped.
+    return [this.m, this];
+};
+var a = "s".m();
+assertEq(a[0], f);
+assertEq(a[1], "s");
+
+reportCompare(true, true);