Embrace -XTypeInType, add -XStarIsType
[ghc.git] / testsuite / tests / polykinds / T9222.hs
1 {-# LANGUAGE RankNTypes, GADTs, DataKinds, PolyKinds, TypeOperators, TypeFamilies #-}
2 module T9222 where
3
4 import Data.Kind
5 import Data.Proxy
6
7 -- Nov 2014: actually the type of Want is ambiguous if we
8 -- do the full co/contra thing for subtyping,
9 -- which we now do
10 -- So this program is erroneous. (But the original ticket was
11 -- a crash, and that's still fixed!)
12
13 data Want :: (i,j) -> Type where
14 Want :: (a ~ '(b,c) => Proxy b) -> Want a