unit p where
    signature A where
        infixl 7 `mul`
        mul :: Int -> Bool -> Char
unit q where
    signature A where
        infixl 7 `mul`
        mul :: Int -> Bool -> Char
unit r where
    dependency p[A=<A>]
    dependency q[A=<A>]
    module B where
        import A
        infixl 6 `plu`
        plu :: () -> Char -> String
        plu = undefined
        x = () `plu` 3 `mul` True