-- @shouldFailWith NoInstanceFound module Main where import Prelude import Control.Monad.Eff (Eff) import Control.Monad.Eff.Console (log) newtype MyType a = MyType a instance cannotShowFunctions :: Fail ("Don't want to show " <> TypeString (MyType a) <> " because.") => Show (MyType a) where show _ = "unreachable" infixl 6 type TypeConcat as <> main :: Eff _ _ main = do log $ show (MyType 2)