Ltac wlt_ind :=
  match goal with
  | [ |- forall (n: word ?len), ?P ] =>
    refine (well_founded_ind (@wlt_wf len) (fun n => P) _)
  end.

Lemma ZToWord_Z_of_N: forall sz n, ZToWord sz (Z.of_N n) = NToWord sz n.