Commit c6f4eac5 authored by Robbert Krebbers's avatar Robbert Krebbers
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Avoid exponential proof search due to Plain → Persistent instance.

parent 0722547a
......@@ -960,7 +960,8 @@ Global Instance limit_preserving_Plain {A:ofeT} `{Cofe A} (Φ : A → uPred M) :
NonExpansive Φ LimitPreserving (λ x, Plain (Φ x)).
Proof. intros. apply limit_preserving_entails; solve_proper. Qed.
Global Instance Plain_Persistent P : Plain P Persistent P.
(* Not an instance, see the bottom of this file *)
Lemma plain_persistent P : Plain P Persistent P.
Proof. rewrite /Plain /Persistent=> HP. by rewrite {1}HP plainly_elim'. Qed.
Lemma plainly_plainly P `{!Plain P} : P P.
......@@ -1061,6 +1062,8 @@ Proof.
rewrite /Persistent -impl_wand pure_impl_forall persistently_forall.
auto using forall_mono.
Global Instance plainly_persistent P : Persistent ( P).
Proof. by rewrite /Persistent persistently_plainly. Qed.
Global Instance persistently_persistent P : Persistent ( P).
Proof. by intros; apply persistently_intro'. Qed.
Global Instance and_persistent P Q :
......@@ -1165,3 +1168,12 @@ Global Instance uPred_ownM_sep_homomorphism :
Proof. split; [split; try apply _|]. apply ownM_op. apply ownM_unit'. Qed.
End derived.
End uPred.
(* When declared as an actual instance, [plain_persistent] will give cause
failing proof searches to take exponential time, as Coq will try to apply it
the instance at any node in the proof search tree.
To avoid that, we declare it using a [Hint Immediate], so that it will only be
used at the leaves of the proof search tree, i.e. when the premise of the hint
can be derived from just the current context. *)
Hint Immediate uPred.plain_persistent : typeclass_instances.
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