T13233.hs:14:11: error:
    Cannot use function with levity-polymorphic arguments:
      GHC.Prim.(#,#) :: a -> a -> (# a, a #)
    Levity-polymorphic arguments:
      a :: TYPE rep
      a :: TYPE rep

T13233.hs:22:16: error:
    Cannot use function with levity-polymorphic arguments:
      GHC.Prim.(#,#) :: forall (rep1 :: RuntimeRep) (rep2 :: RuntimeRep)
                               (a :: TYPE rep1) (b :: TYPE rep2).
                        a -> b -> (# a, b #)
    Levity-polymorphic arguments:
      a :: TYPE rep1
      b :: TYPE rep2