tcfail080.hs:27:1:
    Could not deduce (Collection c0 a)
    from the context: Collection c a
      bound by the inferred type for ‘q’: Collection c a => a -> Bool
      at tcfail080.hs:27:1-27
    The type variable ‘c0’ is ambiguous
    When checking that ‘q’ has the inferred type
      q :: forall (c :: * -> *) a. Collection c a => a -> Bool
    Probable cause: the inferred type is ambiguous