diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug706808.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug706808.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,5 @@
+
+Object.defineProperty(Object.prototype, "a", {});
+function t2(b) { this.a = b; }
+var x = new t2(3);
+assertEq(x.a, undefined);