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Diffstat (limited to 'libraries/base/tests/CatPairs.hs')
| -rw-r--r-- | libraries/base/tests/CatPairs.hs | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/libraries/base/tests/CatPairs.hs b/libraries/base/tests/CatPairs.hs index 6efa9cc574..bcc85e4ea7 100644 --- a/libraries/base/tests/CatPairs.hs +++ b/libraries/base/tests/CatPairs.hs @@ -1,7 +1,9 @@ {-# LANGUAGE PolyKinds, DataKinds, KindSignatures #-} {-# LANGUAGE MultiParamTypeClasses, TypeFamilies #-} module CatPairs where + import Prelude hiding (id, (.)) +import Data.Kind (Type) import Control.Monad ((>=>)) import Control.Category @@ -9,8 +11,8 @@ import Control.Category -- Taken from Twan van Laarhoven: -- http://twanvl.nl/blog/haskell/categories-over-pairs-of-types -type family Fst (xy :: (*,*)) :: * -type family Snd (xy :: (*,*)) :: * +type family Fst (xy :: (Type, Type)) :: Type +type family Snd (xy :: (Type, Type)) :: Type type instance Fst '(x,y) = x type instance Snd '(x,y) = y |