proposition: Lemma refine_If_Then_Else_Duplicate {A} : forall i (t e e' : A), If i Then (If i Then t Else e') Else e = If i Then t Else e.
proof: Proof. destruct i; simpl; reflexivity. Qed.
imports: Coq.Strings.String Coq.Sets.Ensembles Coq.Bool.Bool Fiat.Common Fiat.Common.BoolFacts Fiat.Common.LogicFacts Fiat.Computation.Core Fiat.Computation.Monad Fiat.Computation.SetoidMorphisms Fiat.Computation.Refinements.Tactics