T2688.hs:8:22:
    Could not deduce (s ~ v)
    from the context (VectorSpace v s)
      bound by the class declaration for ‛VectorSpace’
      at T2688.hs:(5,1)-(8,23)
      ‛s’ is a rigid type variable bound by
          the class declaration for ‛VectorSpace’ at T2688.hs:5:21
      ‛v’ is a rigid type variable bound by
          the class declaration for ‛VectorSpace’ at T2688.hs:5:19
    Relevant bindings include
      (^/) :: v -> s -> v (bound at T2688.hs:8:5)
      v :: v (bound at T2688.hs:8:5)
      s :: s (bound at T2688.hs:8:10)
    In the second argument of ‛(/)’, namely ‛s’
    In the second argument of ‛(*^)’, namely ‛(1 / s)’
    In the expression: v *^ (1 / s)