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{-# LANGUAGE ConstraintKinds, MultiParamTypeClasses #-}
module T8359 where
class DifferentTypes a b
type DifferentTypes3 a b c = (DifferentTypes a b, DifferentTypes b c, DifferentTypes a c)
class Foo a
class Bar a
-- Buggy instance requires UndecidableInstances to compile
instance (DifferentTypes3 a b c, Bar a, Bar b, Bar c) => Foo (a, b, c)
-- Equivalent instance compiles when manually expanding constraint type
-- instance (DifferentTypes a b, DifferentTypes b c, DifferentTypes a c, Bar a, Bar b, Bar c) => Foo (a, b, c)
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