newtype Y e = Y { unY :: (e (Y e)) } deriving(Data,Typeable,Show,Read,Eq) gives E.hs:64: Can't make a derived instance of `Typeable (Y e)' (`Y' is parameterised over arguments of kind other than `*') When deriving instances for type `Y' Is there any way around this limitation other than manually expanding Y everywhere I want to use it (which I really don't want to do)? Is the limitation inherent to the way Typeable works, or is it just that no one has implemented it yet? -- John Meacham - ⑆repetae.net⑆john⑈