unit sig where
    signature A where
        x :: Int
        y :: Int

unit blub where
    dependency signature sig[A=<A>]
    signature A (x) where
        x :: Int
    module M (y) where
        import A
        y = x

unit impl where
    module A where
        x :: Int
        x = 2

unit all where
    dependency blub[A=impl:A]