[Haskell-cafe] Eq instance for Chan

Hi! Why is there no Eq instance for Chan? There is Eq for MVar so it is quite possible to define also Eq for Chan? What I would like to do is keep track how many consumers I have for each Chan so duplicating them with dupChan as necessary. So I was thinking of storing a list of Chans which already have a consumer and then duplicating it if another (and every additional) consumer would be added. But without Eq it is not possible to check if there is Chan already in a list (and I hope Eq would compare just Chan and not its content). Is there some other way to achieve this? Mitar