Hi, I try to make my way through #7021 [1]. Unfortunately, there is nothing in the ticket about what should be expected from the code given as example. I came with an implementation and I would like feedback from you guys. So, considering this snippet: -- {-# LANGUAGE ConstraintKinds #-} type IOable a = (Show a, Read a) foo :: IOable a => a foo = undefined -- This is what I got now when pretty-printing TH.Info after reify "foo" call: VarI Tuple.foo (ForallT [PlainTV a_1627398594] [TupleP 2 [AppT (ConT GHC.Show.Show) (VarT a_1627398594),AppT (ConT GHC.Read.Read) (VarT a_1627398594)]] (VarT a_1627398594)) Nothing (Fixity 9 InfixL) Does that sound right to you ? Thanks for your time -- Yorick [1] https://ghc.haskell.org/trac/ghc/ticket/7021