You are probably already aware of this but a declaration such as d1 = [d| id :: a -> a id x = x |] cannot be reified as of yet because the function "trans" in ghc/compiler/hsSyn/Convert.lhs does not contain a clause for the type constructor TForall. The relevent error message is: ghc-5.05: panic! (the `impossible' happened, GHC version 5.05): hsSyn/Convert.lhs:284: Non-exhaustive patterns in function trans Sean