diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/testIncElem4.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/testIncElem4.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,10 @@
+
+var counter = 0;
+var x = { toString: function() { counter++; } };
+var y = {};
+
+for (var i = 0; i < 50; i++)
+  ++y[x];
+
+// :FIXME: bug 672076
+//assertEq(counter, 50);