Let `wp_bind` only `simpl` locally.

theories/heap_lang/proofmode.v

@@ -61,15 +61,16 @@ Tactic Notation "wp_proj" := wp_pure (Fst _) || wp_pure (Snd _).
 Tactic Notation "wp_case" := wp_pure (Case _ _ _).
 Tactic Notation "wp_match" := wp_case; wp_let.
 
-Lemma tac_wp_bind `{heapG Σ} K Δ E Φ e :
-  envs_entails Δ (WP e @ E {{ v, WP fill K (of_val v) @ E {{ Φ }} }})%I →
+Lemma tac_wp_bind `{heapG Σ} K Δ E Φ e f :
+  f = (λ e, fill K e) → (* as an eta expanded hypothesis so that we can `simpl` it *)
+  envs_entails Δ (WP e @ E {{ v, WP f (of_val v) @ E {{ Φ }} }})%I →
   envs_entails Δ (WP fill K e @ E {{ Φ }}).
-Proof. rewrite /envs_entails=> ->. by apply: wp_bind. Qed.
+Proof. rewrite /envs_entails=> -> ->. by apply: wp_bind. Qed.
 
 Ltac wp_bind_core K :=
   lazymatch eval hnf in K with
   | [] => idtac
-  | _ => apply (tac_wp_bind K); simpl
+  | _ => eapply (tac_wp_bind K); [simpl; reflexivity|lazy beta]
   end.
 
 Tactic Notation "wp_bind" open_constr(efoc) :=