proposition: Lemma wcountones_zero {sz} : forall w: word sz, wcountones w = 0%nat -> w = wzero _.
proof: Proof. induction w. - reflexivity. - destruct b; simpl; intros; try discriminate. rewrite IHw by assumption. apply wzero_S. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat List Bedrock.Word Coq.ZArith.ZArith Coq.micromega.Psatz NArith NArithRing ZArith ZArithRing Program Coq.micromega.Psatz