proposition: Lemma first_char_in_empty (str : String) (H : length str = 0) ls : first_char_in str ls.
proof: Proof. unfold first_char_in. apply for_first_char_nil; assumption. Qed.
imports: Fiat.Common.Coq__8_4__8_5__Compat Coq.ZArith.ZArith Fiat.Parsers.StringLike.Core Fiat.Parsers.StringLike.Properties Fiat.Parsers.StringLike.ForallChars Fiat.Common