As I understand it the GHC team are heading towards a release including TH in the not too distant future. I think it would be good if the biggest outstanding issues could be fixed before then (and indeed, just fixed ASAP). The one that causes me the most hoop jumping is the type parameters to some of the TH datastructures. For example, I have some code like this: class ToDec a where to_dec :: a -> Dec instance ToDec Dec where to_dec = id class ToExp a where to_exp :: a -> Exp instance ToExp Exp where to_exp = id instance (ToExp e, ToDec d) => Foo (Match p e d) where foo (Mat p (Normal e) ds) = bar (Normal (Let (map to_dec ds) (to_exp e))) Which I'd much rather be able to write as instance Foo Match where foo (Mat p (Normal e) ds) = bar (Normal (Let (map to_dec ds) (to_exp e))) Previous discussions about this have all petered out before reaching a conclusion, but I haven't seen anyone actually stand up and defend the parameterised types, and it's hard to see how they could be useful without everything being parameterised anyway. Can we get rid of them? Please? Or at least have an explanation of why not... Hmmm, or maybe I should be asking for them to be extended to cover all the types to make it easier to have a type of reification that annotates the tree with type and strictness information. I'd still have the problem above, but at least more things would be possible. Anyway, I'm confused, but sitting in the middle is just driving me mad! Thanks Ian