Isaac Jones
I'm using ghc 5.04.2 which the web page warns may not work with hat.
The good news is that we plan to release a new version of Hat "real soon now", which has full support for ghc-5.04.2, including many of the base hierarchical libraries. Thanks for the specific points you mention however - I have checked to ensure that we have either fixed them already, or will do so before the next release.
After having spent some time getting hat to work, I can't use it on my program since hat does not yet support multi parameter type classes, so I thought I'd voice my opinion that supporting these type classes would be great :)
And the next release of Hat will indeed support MPTC and functional dependencies (provided the underlying compiler does, i.e. they will work with ghc but not with nhc98). Regards, Malcolm