perf experiment: dont make frame_fractional an instance

iris/bi/lib/fractional.v

@@ -14,9 +14,10 @@ Global Arguments AsFractional {_} _%I _%I _%Qp.
 
 Global Arguments fractional {_ _ _} _ _.
 
-Global Hint Mode AsFractional - + - - : typeclass_instances.
+Global Hint Mode AsFractional - ! - - : typeclass_instances.
 (* To make [as_fractional_fractional] a useful instance, we have to
-allow [q] to be an evar. *)
+allow [q] to be an evar. The head of [Φ] will always be a λ so ! is
+not a useful mode there. *)
 Global Hint Mode AsFractional - - + - : typeclass_instances.
 
 Section fractional.
@@ -178,7 +179,8 @@ Section fractional.
   Global Existing Instances frame_fractional_hyps_l frame_fractional_hyps_r
     frame_fractional_hyps_half.
 
-  Global Instance frame_fractional p R r Φ P q RES:
+  (* Not an instance because of performance; you can locally add it if you are willing to pay the cost. *)
+  Lemma frame_fractional p R r Φ P q RES:
     AsFractional R Φ r → AsFractional P Φ q →
     FrameFractionalHyps p R Φ RES r q →
     Frame p R P RES. (* No explicit priority, as default prio > [frame_here]'s 1. *)