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{-# OPTIONS_GHC -fno-warn-redundant-constraints #-}
{-# LANGUAGE DataKinds, FunctionalDependencies, FlexibleInstances,
UndecidableInstances, PolyKinds, KindSignatures,
ConstraintKinds, FlexibleContexts, GADTs #-}
module T6020a where
class Id (a :: k) (b :: k) | b -> a
instance a ~ b => Id a b
class Test (x :: a) (y :: a)
instance (Id x y, Id y z) => Test x z
test :: Test True True => ()
test = ()
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