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{-# LANGUAGE
MultiParamTypeClasses,
FunctionalDependencies,
UndecidableInstances,
FlexibleInstances,
EmptyDataDecls #-}
-- Trac #1797
module ShouldCompile where
data True
data False
class TypeEq type1 type2 result | type1 type2 -> result where
typeEq :: type1 -> type2 -> result
instance TypeEq soleType soleType True where
typeEq _ _ = undefined
instance (TypeCast False result) => TypeEq type1 type2 result where
typeEq _ _ = undefined
class TypeCast type1 type2 | type1 -> type2, type2 -> type1
instance TypeCast soleType soleType
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