gadt13.hs:15:13: error: [GHC-25897] • Could not deduce ‘p ~ (String -> [Char])’ from the context: a ~ Int bound by a pattern with constructor: I :: Int -> Term Int, in an equation for ‘shw’ at gadt13.hs:15:6-8 ‘p’ is a rigid type variable bound by the inferred type of shw :: Term a -> p at gadt13.hs:15:1-30 • In the expression: ("I " ++) . shows t In an equation for ‘shw’: shw (I t) = ("I " ++) . shows t • Relevant bindings include shw :: Term a -> p (bound at gadt13.hs:15:1) Suggested fix: Consider giving ‘shw’ a type signature