diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/pic/watch2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/pic/watch2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// assignments to watched properties via ++ must not be cached
+var obj = {x: 0};
+var hits = 0;
+obj.watch("x", function (id, oldval, newval) { hits++; return newval; });
+for (var i = 0; i < 10; i++)
+    obj.x++;
+assertEq(hits, 10);
+