{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE AllowAmbiguousTypes #-}  -- 'bar' is ambiguous

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