proposition: Lemma decode_string_aligned_ByteString_overflow {sz} : forall {sz'} (b : t (word 8) sz') (cd : CacheDecode), lt sz' sz -> FixStringOpt.decode_string sz (build_aligned_ByteString b) cd = None.
proof: Proof. induction sz; intros. - omega. - simpl. assert (forall A n b, exists a b', b = Vector.cons A a n b') by (clear; intros; pattern n, b; apply caseS; eauto). destruct sz'. + reflexivity. + destruct (H0 _ _ b) as [? [? ?] ]; subst; simpl. unfold AsciiOpt.decode_ascii, DecodeBindOpt2. rewrite BindOpt_assoc; simpl. etransitivity. unfold BindOpt. rewrite AlignedDecodeChar; simpl. rewrite IHsz. higher_order_reflexivity. omega. reflexivity. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Coq.Strings.Ascii Coq.Strings.String Coq.Arith.Mult Coq.Vectors.Vector Fiat.Common.SumType Fiat.Common.BoundedLookup Fiat.Common.ilist Fiat.Common.DecideableEnsembles Fiat.Computation Fiat.Narcissus.Common.Specs Fiat.Narcissus.Common.ComposeOpt Fiat.Narcissus.Formats.FixStringOpt Fiat.Narcissus.Formats.StringOpt Fiat.Narcissus.Formats.EnumOpt Fiat.Narcissus.Formats.FixListOpt Fiat.Narcissus.Formats.SumTypeOpt Fiat.Narcissus.Formats.AsciiOpt Fiat.Narcissus.BinLib.AlignedByteString Fiat.Narcissus.BinLib.AlignWord Fiat.Common.IterateBoundedIndex Fiat.Common.Tactics.CacheStringConstant Bedrock.Word