[Haskell-cafe] GADTs and Typeclasses

Will I run into problems using typeclasses with GADTs? I've come up with this to model a fragment of ASN.1. I'd hate to spend a lot of time on this only to find out it's well known that these two features don't mix very well. Thanks, Dominic. data Type :: * -> * where INTEGER :: Type Int BOOLEAN :: Type Bool BITSTRING :: Type BitString NUMERICSTRING :: Type NumericString ReferencedType :: Type () -- for now ConstrainedType :: Type a -> Constraint a -> Type a SizeConstrainedType :: Size a => Type a -> Constraint Int -> Type a FromConstrainedType :: From a => Type a -> Constraint a -> Type a