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{-# LANGUAGE TypeFamilies #-}
module TH_tf2 where
{-
$( [d| class C a where
data T a
foo :: Bool -> T a |] )
$( [d| instance C Int where
data T Int = TInt Bool
foo b = TInt (b && b) |] )
$( [d| instance C Float where
data T Float = TFloat {flag :: Bool}
foo b = TFloat {flag = b && b} |] )
-}
class D a where
type S a
bar :: S a -> Int
instance D Int where
type S Int = Bool
bar c = if c then 1 else 2
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