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

Lemma Zeqb_true_ZToWord: forall {sz: nat} (x y: Z), (x =? y)%Z = true -> ZToWord sz x = ZToWord sz y.