Make iFrame able to strip a later from a framed hypothesis when framing under a later.

algebra/upred.v

@@ -1472,6 +1472,7 @@ Qed.
 
 Theorem soundness : ¬ (True ⊢ False).
 Proof. exact (adequacy False 0). Qed.
+
 End uPred_logic.
 
 (* Hint DB for the logic *)

proofmode/class_instances.v

@@ -269,10 +269,10 @@ Proof. by rewrite /MakeLater later_True. Qed.
 Global Instance make_later_default P : MakeLater P (▷ P) | 100.
 Proof. done. Qed.
 
-Global Instance frame_later R P Q Q' :
-  Frame R P Q → MakeLater Q Q' → Frame R (▷ P) Q'.
+Global Instance frame_later R R' P Q Q' :
+  Frame R P Q → MakeLater Q Q' → IntoLater R' R → Frame R' (▷ P) Q'.
 Proof.
-  rewrite /Frame /MakeLater=><- <-. by rewrite later_sep -(later_intro R).
+  rewrite /Frame /MakeLater /IntoLater=><- <- ->. by rewrite later_sep.
 Qed.
 
 Class MakeExceptLast (P Q : uPred M) := make_except_last : ◇ P ⊣⊢ Q.