proposition: Lemma typing_ty_appI {Gamma P t s s'}: typing Gamma P (poly_abs s) -> t = (subst_poly_type (s' .: poly_var) s) -> typing Gamma (ty_app P s') t.
proof: Proof. move=> + ->. by apply: typing_ty_app. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Autosubst.unscoped Undecidability.SystemF.Util(Facts poly_type_facts term_facts) ssreflect ssrbool ssrfun