proposition: Lemma iipc2I {Gamma P t} : typing Gamma P t -> iipc2 Gamma t.
proof: Proof. move=> ?. eexists. by eassumption. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Util(Facts poly_type_facts typing_facts) ssreflect ssrbool ssrfun