Actually I agree with you. In fact if you look at the 'UnbalancedSet' functor I define the type 'T' to not take any parameters. In the case of 'IntMap' it just

Actually I agree with you. In fact if you look at the 'UnbalancedSet' functor I define the type 'T' to not take any parameters. In the case of 'IntMap' it just happened that I missed that. So thanks for pointing it out. I'll make the necessary updates.