diff --git a/theories/typing/type.v b/theories/typing/type.v
index 401392ae02e3b6a3ce1bd5938e165ecf789a0e56..0e8fdeaefb11fe81db02b3b65cd9894f4ba82e8f 100644
--- a/theories/typing/type.v
+++ b/theories/typing/type.v
@@ -73,6 +73,7 @@ Proof.
     + apply IH, Hαβ. etrans; last done. by apply submseteq_cons.
 Qed.
 
+(* Lift TyWf to lists.  We cannot use `Forall` because that one is restricted to Prop. *)
 Inductive TyWfLst `{typeG Σ} : list type → Type :=
 | tyl_wf_nil : TyWfLst []
 | tyl_wf_cons ty tyl `{!TyWf ty, !TyWfLst tyl} : TyWfLst (ty::tyl).