diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/pic/watch4.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/pic/watch4.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,9 @@
+// adding assignment + watchpoint vs. caching
+var hits = 0;
+var obj = {};
+obj.watch("x", function (id, oldval, newval) { hits++; return newval; });
+for (var i = 0; i < 10; i++) {
+    obj.x = 1;
+    delete obj.x;
+}
+assertEq(hits, 10);