proposition: Lemma eutt_ret (r1 r2 : R) : r1 = r2 -> Ret r1 ≈ Ret r2.
proof: Proof. intros. subst. reflexivity. Qed.
imports: Coq(Setoid Morphisms) ITree(Eq.Shallow) ITree.Core.ITreeDefinition ITree.Basics.Basics ITree.Indexed.Sum ITree.Interp.Interp ITree.Interp.Recursion ITree(Eq.Eqit Eq.UpToTaus Interp.InterpFacts Interp.RecursionFacts)