unit p where
    signature H where
        type T = Int
    module M where
        import H
        f :: T
        f = 2
unit q where
    signature H2 where
        type S = Bool
    module N where
        import H2
        type T = Int
unit badimpl where
    module H2 where
        type S = ()
unit check where
    dependency q[H2=badimpl:H2]
    dependency p[H=q[H2=badimpl:H2]:N]
    -- signature H3 where
    module C where
        import M