setTimeout does not pass additional parameters correctly

[Ventero]

When supplying additional parameters (that is, parameters other than callback and timeout delay) to setTimeout, they are not correctly passed on. Instead, an array of all additional parameters is passed to the callback as first parameter, and a nsITimer instance as second parameter.

Example testcase (direct link to gist):

// ==UserScript==
// @name        Timeout additional parameter test
// @namespace   ventero.de
// @include     *
// @version     1
// ==/UserScript==

setTimeout(function(a, b){alert(a.foo + "//" + typeof b)}, 0, {foo:1}, {});

Steps to reproduce: Refresh any website
Expected output: An alert showing "1//object".
Observed output: An alert showing "undefined//object".