When using [iAssert ... with ">[]"], we should not use...

When using [iAssert ... with ">[]"], we should not use [tac_assert_persistent], and eliminate the modality instead.

This patch is still not ideal, because some modalities (e.g., later) preserve persistence.

theories/proofmode/tactics.v

@@ -1247,7 +1247,7 @@ Tactic Notation "iAssertCore" open_constr(Q)
        |tac H]
   | [SGoal (SpecGoal ?m ?lr ?Hs_frame ?Hs)] =>
      let Hs' := eval cbv in (if lr then Hs else Hs_frame ++ Hs) in
-     match p with
+     match eval cbv in (p && negb m) with
      | false =>
        eapply tac_assert with _ _ _ lr Hs' H Q _;
          [match m with

theories/tests/proofmode.v

@@ -124,3 +124,6 @@ Proof. iIntros "H HP HQ". by iApply ("H" with "[HP]"). Qed.
 (* Check coercions *)
 Lemma demo_12 (M : ucmraT) (P : Z → uPred M) : (∀ x, P x) -∗ ∃ x, P x.
 Proof. iIntros "HP". iExists (0:nat). iApply ("HP" $! (0:nat)). Qed.
+
+Lemma demo_13 (M : ucmraT) (P : uPred M) : (|==> False) -∗ |==> P.
+Proof. iIntros. iAssert False%I with ">[-]" as "[]". done. Qed.