diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/ion/bug728187.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/ion/bug728187.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,10 @@
+function f(x) {
+    if (x.y()) {};
+}
+f({y: function() {}});
+try {
+    f(10);
+    assertEq(0, 1);
+} catch(e) {
+    assertEq(e instanceof TypeError, true);
+}