Improve error messages around kind mismatches.
[ghc.git] / testsuite / tests / typecheck / should_fail / T3950.hs
1 {-# LANGUAGE GADTs #-}
2
3 module T3950 where
4
5 -- Id :: (* -> * -> *) -> * -> * -> *
6 data Id p x y = Id (p x y)
7
8 -- Sealed :: (* -> *) -> *
9 data Sealed p where
10 Sealed :: p x -> Sealed p
11
12 -- w :: (* -> * -> *) -> *
13 -- Id p :: * -> * -> *
14 rp :: Bool -> Maybe (w (Id p))
15 rp _ = Just rp'
16 where rp' :: Sealed (Id p x)
17 rp' = undefined