diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug683140.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug683140.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,13 @@
+
+var g = newGlobal("same-compartment");
+g.eval("this.f = function(a) {" +
+       "assertEq(a instanceof Array, false);" +
+       "a = Array.prototype.slice.call(a);" +
+       "assertEq(a instanceof Array, true); }");
+g.f([1, 2, 3]);
+
+var g2 = newGlobal();
+g2.a = g2.Array(10);
+assertEq(g2.a instanceof Array, false);
+g2.a = Array.prototype.slice(g2.a);
+assertEq(g2.a instanceof Array, true);