diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug830967.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug830967.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,4 @@
+var x = Array.concat(Object.freeze([{}]));
+assertEq(x.length, 1);
+assertEq(0 in x, true);
+assertEq(JSON.stringify(x[0]), "{}");