diff -r 000000000000 -r 6474c204b198 js/src/tests/js1_8_5/extensions/regress-627984-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/js1_8_5/extensions/regress-627984-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+// Any copyright is dedicated to the Public Domain.
+// http://creativecommons.org/licenses/publicdomain/
+
+// See bug 627984, comment 17, item 1.
+var obj;
+var methods = [];
+for (var i = 0; i < 2; i++) {
+    obj = {m: function () { return this.x; }};
+    obj.watch("m", function (id, oldval, newval) { methods[i] = oldval; });
+    obj.m = 0;
+}
+assertEq(typeof methods[0], "function");
+assertEq(typeof methods[1], "function");
+assertEq(methods[0] !== methods[1], true);
+
+reportCompare(0, 0, 'ok');