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{-# LANGUAGE DeriveGeneric, ScopedTypeVariables, TemplateHaskell #-}
module Main where
import GHC.Generics (Generic)
import Test.QuickCheck
import Test.QuickCheck.Function
data D a = C1 a | C2 deriving (Eq, Show, Read, Generic)
instance Arbitrary a => Arbitrary (D a) where arbitrary = error "not implemented"
instance CoArbitrary a => CoArbitrary (D a)
instance (Show a, Read a) => Function (D a) where
function = functionShow
prop_coarbitrary (Fun _ f) =
expectFailure $
withMaxSuccess 1000 $
f (C1 (2::Int)) `elem` [0, 1 :: Int]
return []
main = do True <- $quickCheckAll; return ()
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