{-# LANGUAGE DefaultSignatures #-}
{-# OPTIONS_GHC -O #-}
unit p where
    signature A where
        class C a where
            f :: a -> a
        class D a where
            g :: a
            default g :: a
        class E a where
            h :: a -> String
            default h :: Show a => a -> String
    module B where
        class X a where
            i :: String -> a
            default i :: Read a => String -> a
            i = read
        instance X Int where
unit i where
    module A where
        class C a where
            f :: a -> a
            f x = x
        class D a where
            g :: a
            g = undefined
        class E a where
            h :: a -> String
            default h :: Show a => a -> String
            h = show
unit m where
    dependency p[A=i:A]