T18451.hs:10:58: error:
    • Expected kind ‘k0’, but ‘b’ has kind ‘k’
      Type variable kinds:
        a :: k0
        k :: Const (*) a
    • In the second argument of ‘SameKind’, namely ‘b’
      In the type ‘forall (b :: k). SameKind a b’
      In the type declaration for ‘T’