proposition: Lemma decides_Option_eq_None {B} : forall (s_opt : option B) b, (Ifopt s_opt as _ Then true Else false) = b -> decides (negb b) (s_opt = None).
proof: Proof. intros; destruct s_opt; simpl in *; subst; simpl in *; congruence. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.Bool.Bool Coq.ZArith.ZArith Coq.Lists.List Fiat.Common.DecideableEnsembles Fiat.Common.EnumType Fiat.Common.BoundedLookup Fiat.Common Fiat.Common.ilist Fiat.Common.Tactics.CacheStringConstant Fiat.Common.IterateBoundedIndex Fiat.Computation Bedrock.Word