arian/mootools-core — comment on commit 9293d6120a1f7f2d1febeebd3ef7d5efc085e506
File:  line 0
By arian:

Exactly. The only places where this was really necessary was `if (isType) object.implement(prototype);` (which uses the for-in in overloadSetter) and in `Elements.implement(Array.prototype);`. Besides that everything seems to work (specs pass in IE6, IE8 and Chrome).