From b8ba5d8a2315fc55837eb389e496ea18d2bc57fb Mon Sep 17 00:00:00 2001
From: Ralf Jung
Date: Thu, 16 Nov 2017 10:25:35 +0100
Subject: [PATCH] factor out solve_proper preparation into a separate tactic

theories/tactics.v  21 ++++++++++++++
1 file changed, 14 insertions(+), 7 deletions()
diff git a/theories/tactics.v b/theories/tactics.v
index bcdc20f..fc019e6 100644
 a/theories/tactics.v
+++ b/theories/tactics.v
@@ 335,11 +335,10 @@ Ltac solve_proper_unfold :=
  ?R (?f _ _) (?f _ _) => unfold f
  ?R (?f _) (?f _) => unfold f
end.

(** The tactic [solve_proper_core tac] solves goals of the form "Proper (R1 ==> R2)", for
any number of relations. The actual work is done by repeatedly applying
[tac]. *)
Ltac solve_proper_core tac :=
+(* [solve_proper_prepare] does some preparation work before the main
+ [solve_proper] loop. Having this as a separate tactic is useful for
+ debugging [solve_proper] failure. *)
+Ltac solve_proper_prepare :=
(* Introduce everything *)
intros;
repeat lazymatch goal with
@@ 348,10 +347,18 @@ Ltac solve_proper_core tac :=
  pointwise_relation _ _ _ _ => intros ?
  ?R ?f _ => try let f' := constr:(λ x, f x) in intros ?
end; simplify_eq;
 (* Now do the job. We try with and without unfolding. We have to backtrack on
+ (* We try with and without unfolding. We have to backtrack on
that because unfolding may succeed, but then the proof may fail. *)
 (solve_proper_unfold + idtac); simpl;
+ (solve_proper_unfold + idtac); simpl.
+(** The tactic [solve_proper_core tac] solves goals of the form "Proper (R1 ==> R2)", for
+any number of relations. The actual work is done by repeatedly applying
+[tac]. *)
+Ltac solve_proper_core tac :=
+ solve_proper_prepare;
+ (* Now do the job. *)
solve [repeat first [eassumption  tac ()] ].
+
+(** Finally, [solve_proper] tries to apply [f_equiv] in a loop. *)
Ltac solve_proper := solve_proper_core ltac:(fun _ => f_equiv).
(** The tactic [intros_revert tac] introduces all foralls/arrows, performs tac,

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