testsuite/tests/typecheck/should_compile/T10423.hs


1
2
3
4
5
6
7
8
9

{-# LANGUAGE FlexibleInstances, TypeFamilies, MultiParamTypeClasses #-}

module T10423 where

class Monad m => Testable m a

newtype Prop m = MkProp (m Int)

instance (Monad m, m ~ n) => Testable n (Prop m)