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{-# LANGUAGE Haskell2010 #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE StandaloneKindSignatures #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
module T14141_Unsat where
import GHC.TypeError
import Data.Kind
( Constraint, Type )
-- Example 1: from #14141
data D where
MkD :: C => D
type C :: Constraint
type family C where
C = Unsatisfiable ('Text "error")
f :: D -> ()
f MkD = ()
-- Example 2: from #16377
type F :: Type -> Constraint
type family F a :: Constraint
type instance F Int = ()
type instance F Char = Unsatisfiable ('Text "Nope")
data T where
A :: F Int => T
B :: F Char => T
exhaustive :: T -> ()
exhaustive A = ()
exhaustive B = ()
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