Definition wring (sz : nat) : ring_theory (wzero sz) (wone sz) (@wplus sz) (@wmult sz) (@wminus sz) (@wneg sz) (@eq _) :=
mk_rt _ _ _ _ _ _ _
(@wplus_unit _) (@wplus_comm _) (@wplus_assoc _)
(@wmult_unit _) (@wmult_comm _) (@wmult_assoc _)
(@wmult_plus_distr _) (@wminus_def _) (@wminus_inv _).

Theorem weqb_sound : forall sz (x y : word sz), weqb x y = true -> x = y.
Arguments weqb_sound : clear implicits.