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{-# LANGUAGE TypeFamilies #-}
module ShouldFail where
class C3 a where
data S3 a :: *
data S3n a :: *
foo3 :: a -> S3 a
foo3n :: a -> S3n a
bar3 :: S3 a -> a
bar3n :: S3n a -> a
instance C3 Int where
data S3 Int = D3Int
newtype S3n Int = D3Intn ()
foo3 _ = D3Int
foo3n _ = D3Intn ()
bar3 D3Int = 1
bar3n (D3Intn _) = 1
instance C3 Char where
data S3 Char = D3Char
foo3 _ = D3Char
bar3 D3Char = 'c'
bar3' :: S3 Char -> Char
bar3' D3Char = 'a'
-- must fail: signature too general
bar3wrong :: S3 a -> a
bar3wrong D3Int = 1
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