# Library stdpp.tactics

This file collects general purpose tactics that are used throughout
the development.

From Coq Require Export Lia.

From stdpp Require Export decidable.

From stdpp Require Import options.

Lemma f_equal_dep {A B} (f g : ∀ x : A, B x) x : f = g → f x = g x.

Proof. intros ->; reflexivity. Qed.

Lemma f_equal_help {A B} (f g : A → B) x y : f = g → x = y → f x = g y.

Proof. intros → ->; reflexivity. Qed.

Ltac f_equal :=

let rec go :=

match goal with

| _ ⇒ reflexivity

| _ ⇒ apply f_equal_help; [go|try reflexivity]

| |- ?f ?x = ?g ?x ⇒ apply (f_equal_dep f g); go

end in

try go.

From stdpp Require Export decidable.

From stdpp Require Import options.

Lemma f_equal_dep {A B} (f g : ∀ x : A, B x) x : f = g → f x = g x.

Proof. intros ->; reflexivity. Qed.

Lemma f_equal_help {A B} (f g : A → B) x y : f = g → x = y → f x = g y.

Proof. intros → ->; reflexivity. Qed.

Ltac f_equal :=

let rec go :=

match goal with

| _ ⇒ reflexivity

| _ ⇒ apply f_equal_help; [go|try reflexivity]

| |- ?f ?x = ?g ?x ⇒ apply (f_equal_dep f g); go

end in

try go.

We declare hint databases f_equal, congruence and lia and containing
solely the tactic corresponding to its name. These hint database are useful in
to be combined in combination with other hint database.

Global Hint Extern 998 (_ = _) ⇒ f_equal : f_equal.

Global Hint Extern 999 ⇒ congruence : congruence.

Global Hint Extern 1000 ⇒ lia : lia.

Global Hint Extern 1001 ⇒ progress subst : subst.

Global Hint Extern 999 ⇒ congruence : congruence.

Global Hint Extern 1000 ⇒ lia : lia.

Global Hint Extern 1001 ⇒ progress subst : subst.

backtracking on this one will
be very bad, so use with care!
The tactic intuition expands to intuition auto with × by default. This
is rather efficient when having big hint databases, or expensive Hint Extern
declarations as the ones above.

Tactic Notation "intuition" := intuition auto.

done can get slow as it calls "trivial". fast_done can solve way less
goals, but it will also always finish quickly. We do 'reflexivity' last because
for goals of the form ?x = y, if we have x = y in the context, we will typically
want to use the assumption and not reflexivity

Ltac fast_done :=

solve

[ eassumption

| symmetry; eassumption

| apply not_symmetry; eassumption

| reflexivity ].

Tactic Notation "fast_by" tactic(tac) :=

tac; fast_done.

Class TCFastDone (P : Prop) : Prop := tc_fast_done : P.

Global Hint Extern 1 (TCFastDone ?P) ⇒ (change P; fast_done) : typeclass_instances.

solve

[ eassumption

| symmetry; eassumption

| apply not_symmetry; eassumption

| reflexivity ].

Tactic Notation "fast_by" tactic(tac) :=

tac; fast_done.

Class TCFastDone (P : Prop) : Prop := tc_fast_done : P.

Global Hint Extern 1 (TCFastDone ?P) ⇒ (change P; fast_done) : typeclass_instances.

A slightly modified version of Ssreflect's finishing tactic done. It
also performs reflexivity and uses symmetry of negated equalities. Compared
to Ssreflect's done, it does not compute the goal's hnf so as to avoid
unfolding setoid equalities. Note that this tactic performs much better than
Coq's easy tactic as it does not perform inversion.

Ltac done :=

solve

[ repeat first

[ fast_done

| solve [trivial]

| progress intros

| solve [symmetry; trivial]

| solve [apply not_symmetry; trivial]

| discriminate

| contradiction

| split

| match goal with H : ¬_ |- _ ⇒ case H; clear H; fast_done end ]

].

Tactic Notation "by" tactic(tac) :=

tac; done.

Ltac done_if b :=

match b with

| true ⇒ done

| false ⇒ idtac

end.

solve

[ repeat first

[ fast_done

| solve [trivial]

| progress intros

| solve [symmetry; trivial]

| solve [apply not_symmetry; trivial]

| discriminate

| contradiction

| split

| match goal with H : ¬_ |- _ ⇒ case H; clear H; fast_done end ]

].

Tactic Notation "by" tactic(tac) :=

tac; done.

Ltac done_if b :=

match b with

| true ⇒ done

| false ⇒ idtac

end.

Aliases for transitivity and etransitivity that are easier to type

Tactic Notation "trans" constr(A) := transitivity A.

Tactic Notation "etrans" := etransitivity.

Tactic Notation "etrans" := etransitivity.

Tactics for splitting conjunctions:
Note that split_and differs from split by only splitting conjunctions. The
split tactic splits any inductive with one constructor.

- split_and : split the goal if is syntactically of the shape _ ∧ _
- split_and? : split the goal repeatedly (perhaps zero times) while it is of the shape _ ∧ _.
- split_and! : works similarly, but at least one split should succeed. In order to do so, it will head normalize the goal first to possibly expose a conjunction.

- destruct_and? H : destruct assumption H repeatedly (perhaps zero times) while it is of the shape _ ∧ _.
- destruct_and! H : works similarly, but at least one destruct should succeed. In order to do so, it will head normalize the goal first to possibly expose a conjunction.
- destruct_and? iterates destruct_or? H on every matching assumption H.
- destruct_and! works similarly, but at least one destruct should succeed.

Tactic Notation "split_and" :=

match goal with

| |- _ ∧ _ ⇒ split

| |- Is_true (_ && _) ⇒ apply andb_True; split

end.

Tactic Notation "split_and" "?" := repeat split_and.

Tactic Notation "split_and" "!" := hnf; split_and; split_and?.

Ltac destruct_and_go H :=

try lazymatch type of H with

| True ⇒ clear H

| _ ∧ _ ⇒

let H1 := fresh in

let H2 := fresh in

destruct H as [ H1 H2 ];

destruct_and_go H1; destruct_and_go H2

| Is_true (bool_decide _) ⇒

apply (bool_decide_unpack _) in H;

destruct_and_go H

| Is_true (_ && _) ⇒

apply andb_True in H;

destruct_and_go H

end.

Tactic Notation "destruct_and" "?" ident(H) :=

destruct_and_go H.

Tactic Notation "destruct_and" "!" ident(H) :=

hnf in H; progress (destruct_and? H).

Tactic Notation "destruct_and" "?" :=

repeat match goal with H : _ |- _ ⇒ progress (destruct_and? H) end.

Tactic Notation "destruct_and" "!" :=

progress destruct_and?.

match goal with

| |- _ ∧ _ ⇒ split

| |- Is_true (_ && _) ⇒ apply andb_True; split

end.

Tactic Notation "split_and" "?" := repeat split_and.

Tactic Notation "split_and" "!" := hnf; split_and; split_and?.

Ltac destruct_and_go H :=

try lazymatch type of H with

| True ⇒ clear H

| _ ∧ _ ⇒

let H1 := fresh in

let H2 := fresh in

destruct H as [ H1 H2 ];

destruct_and_go H1; destruct_and_go H2

| Is_true (bool_decide _) ⇒

apply (bool_decide_unpack _) in H;

destruct_and_go H

| Is_true (_ && _) ⇒

apply andb_True in H;

destruct_and_go H

end.

Tactic Notation "destruct_and" "?" ident(H) :=

destruct_and_go H.

Tactic Notation "destruct_and" "!" ident(H) :=

hnf in H; progress (destruct_and? H).

Tactic Notation "destruct_and" "?" :=

repeat match goal with H : _ |- _ ⇒ progress (destruct_and? H) end.

Tactic Notation "destruct_and" "!" :=

progress destruct_and?.

Tactics for splitting disjunctions in an assumption:

- destruct_or? H : destruct the assumption H repeatedly (perhaps zero times) while it is of the shape _ ∨ _.
- destruct_or! H : works similarly, but at least one destruct should succeed. In order to do so, it will head normalize the goal first to possibly expose a disjunction.
- destruct_or? iterates destruct_or? H on every matching assumption H.
- destruct_or! works similarly, but at least one destruct should succeed.

Tactic Notation "destruct_or" "?" ident(H) :=

repeat match type of H with

| False ⇒ destruct H

| _ ∨ _ ⇒ destruct H as [H|H]

| Is_true (bool_decide _) ⇒ apply (bool_decide_unpack _) in H

| Is_true (_ || _) ⇒ apply orb_True in H; destruct H as [H|H]

end.

Tactic Notation "destruct_or" "!" ident(H) := hnf in H; progress (destruct_or? H).

Tactic Notation "destruct_or" "?" :=

repeat match goal with H : _ |- _ ⇒ progress (destruct_or? H) end.

Tactic Notation "destruct_or" "!" :=

progress destruct_or?.

repeat match type of H with

| False ⇒ destruct H

| _ ∨ _ ⇒ destruct H as [H|H]

| Is_true (bool_decide _) ⇒ apply (bool_decide_unpack _) in H

| Is_true (_ || _) ⇒ apply orb_True in H; destruct H as [H|H]

end.

Tactic Notation "destruct_or" "!" ident(H) := hnf in H; progress (destruct_or? H).

Tactic Notation "destruct_or" "?" :=

repeat match goal with H : _ |- _ ⇒ progress (destruct_or? H) end.

Tactic Notation "destruct_or" "!" :=

progress destruct_or?.

The tactic case_match destructs an arbitrary match in the conclusion or
assumptions, and generates a corresponding equality. This tactic is best used
together with the repeat tactical.

Ltac case_match :=

match goal with

| H : context [ match ?x with _ ⇒ _ end ] |- _ ⇒ destruct x eqn:?

| |- context [ match ?x with _ ⇒ _ end ] ⇒ destruct x eqn:?

end.

match goal with

| H : context [ match ?x with _ ⇒ _ end ] |- _ ⇒ destruct x eqn:?

| |- context [ match ?x with _ ⇒ _ end ] ⇒ destruct x eqn:?

end.

The tactic unless T by tac_fail succeeds if T is not provable by
the tactic tac_fail.

Tactic Notation "unless" constr(T) "by" tactic3(tac_fail) :=

first [assert T by tac_fail; fail 1 | idtac].

first [assert T by tac_fail; fail 1 | idtac].

The tactic repeat_on_hyps tac repeatedly applies tac in unspecified
order on all hypotheses until it cannot be applied to any hypothesis anymore.

Tactic Notation "repeat_on_hyps" tactic3(tac) :=

repeat match goal with H : _ |- _ ⇒ progress tac H end.

repeat match goal with H : _ |- _ ⇒ progress tac H end.

The tactic clear dependent H1 ... Hn clears the hypotheses Hi and
their dependencies.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) :=

clear dependent H1; clear dependent H2.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) :=

clear dependent H1 H2; clear dependent H3.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) :=

clear dependent H1 H2 H3; clear dependent H4.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4)

hyp(H5) := clear dependent H1 H2 H3 H4; clear dependent H5.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) := clear dependent H1 H2 H3 H4 H5; clear dependent H6.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) := clear dependent H1 H2 H3 H4 H5 H6; clear dependent H7.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) :=

clear dependent H1 H2 H3 H4 H5 H6 H7; clear dependent H8.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) hyp(H9) :=

clear dependent H1 H2 H3 H4 H5 H6 H7 H8; clear dependent H9.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) hyp(H9) hyp(H10) :=

clear dependent H1 H2 H3 H4 H5 H6 H7 H8 H9; clear dependent H10.

clear dependent H1; clear dependent H2.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) :=

clear dependent H1 H2; clear dependent H3.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) :=

clear dependent H1 H2 H3; clear dependent H4.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4)

hyp(H5) := clear dependent H1 H2 H3 H4; clear dependent H5.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) := clear dependent H1 H2 H3 H4 H5; clear dependent H6.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) := clear dependent H1 H2 H3 H4 H5 H6; clear dependent H7.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) :=

clear dependent H1 H2 H3 H4 H5 H6 H7; clear dependent H8.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) hyp(H9) :=

clear dependent H1 H2 H3 H4 H5 H6 H7 H8; clear dependent H9.

Tactic Notation "clear" "dependent" hyp(H1) hyp(H2) hyp(H3) hyp(H4) hyp(H5)

hyp (H6) hyp(H7) hyp(H8) hyp(H9) hyp(H10) :=

clear dependent H1 H2 H3 H4 H5 H6 H7 H8 H9; clear dependent H10.

The tactic is_non_dependent H determines whether the goal's conclusion or
hypotheses depend on H.

Tactic Notation "is_non_dependent" constr(H) :=

match goal with

| _ : context [ H ] |- _ ⇒ fail 1

| |- context [ H ] ⇒ fail 1

| _ ⇒ idtac

end.

match goal with

| _ : context [ H ] |- _ ⇒ fail 1

| |- context [ H ] ⇒ fail 1

| _ ⇒ idtac

end.

The tactic var_eq x y fails if x and y are unequal, and var_neq
does the converse.

Ltac var_eq x1 x2 := match x1 with x2 ⇒ idtac | _ ⇒ fail 1 end.

Ltac var_neq x1 x2 := match x1 with x2 ⇒ fail 1 | _ ⇒ idtac end.

Ltac var_neq x1 x2 := match x1 with x2 ⇒ fail 1 | _ ⇒ idtac end.

The tactic mk_evar T returns a new evar of type T, without affecting the
current context.
This is usually a more useful behavior than Coq's evar, which is a
side-effecting tactic (not returning anything) that introduces a local
definition into the context that holds the evar.
Note that the obvious alternative open_constr (_:T) has subtly different
behavior, see std++ issue 115.
Usually, Ltacs cannot return a value and have a side-effect, but we use the
trick described at
<https://stackoverflow.com/questions/45949064/check-for-evars-in-a-tactic-that-returns-a-value/4617888446178884>
to work around that: wrap the side-effect in a [match goal].

Ltac mk_evar T :=

let T := constr:(T : Type) in

let e := fresh in

let _ := match goal with _ ⇒ evar (e:T) end in

let e' := eval unfold e in e in

let _ := match goal with _ ⇒ clear e end in

e'.

let T := constr:(T : Type) in

let e := fresh in

let _ := match goal with _ ⇒ evar (e:T) end in

let e' := eval unfold e in e in

let _ := match goal with _ ⇒ clear e end in

e'.

The tactic get_head t returns the head function f when t is of the
shape f a1 ... aN. This is purely syntactic, no unification is performed.

Ltac get_head e :=

lazymatch e with

| ?h _ ⇒ get_head h

| _ ⇒ e

end.

lazymatch e with

| ?h _ ⇒ get_head h

| _ ⇒ e

end.

The tactic eunify x y succeeds if x and y can be unified, and fails
otherwise. If it succeeds, it will instantiate necessary evars in x and y.
Contrary to Coq's standard unify tactic, which uses constr for the arguments
x and y, eunify uses open_constr so that one can use holes (i.e., _s).
For example, it allows one to write eunify x (S _), which will test if x
unifies a successor.

Tactic Notation "eunify" open_constr(x) open_constr(y) :=

unify x y.

unify x y.

Operational type class projections in recursive calls are not folded back
appropriately by simpl. The tactic csimpl uses the fold_classes tactics
to refold recursive calls of fmap, mbind, omap and alter. A
self-contained example explaining the problem can be found in the following
Coq-club message:
https://sympa.inria.fr/sympa/arc/coq-club/2012-10/msg00147.html

Ltac fold_classes :=

repeat match goal with

| |- context [ ?F ] ⇒

progress match type of F with

| FMap _ ⇒

change F with (@fmap _ F);

repeat change (@fmap _ (@fmap _ F)) with (@fmap _ F)

| MBind _ ⇒

change F with (@mbind _ F);

repeat change (@mbind _ (@mbind _ F)) with (@mbind _ F)

| OMap _ ⇒

change F with (@omap _ F);

repeat change (@omap _ (@omap _ F)) with (@omap _ F)

| Alter _ _ _ ⇒

change F with (@alter _ _ _ F);

repeat change (@alter _ _ _ (@alter _ _ _ F)) with (@alter _ _ _ F)

end

end.

Ltac fold_classes_hyps H :=

repeat match type of H with

| context [ ?F ] ⇒

progress match type of F with

| FMap _ ⇒

change F with (@fmap _ F) in H;

repeat change (@fmap _ (@fmap _ F)) with (@fmap _ F) in H

| MBind _ ⇒

change F with (@mbind _ F) in H;

repeat change (@mbind _ (@mbind _ F)) with (@mbind _ F) in H

| OMap _ ⇒

change F with (@omap _ F) in H;

repeat change (@omap _ (@omap _ F)) with (@omap _ F) in H

| Alter _ _ _ ⇒

change F with (@alter _ _ _ F) in H;

repeat change (@alter _ _ _ (@alter _ _ _ F)) with (@alter _ _ _ F) in H

end

end.

Tactic Notation "csimpl" "in" hyp(H) :=

try (progress simpl in H; fold_classes_hyps H).

Tactic Notation "csimpl" := try (progress simpl; fold_classes).

Tactic Notation "csimpl" "in" "*" :=

repeat_on_hyps (fun H ⇒ csimpl in H); csimpl.

repeat match goal with

| |- context [ ?F ] ⇒

progress match type of F with

| FMap _ ⇒

change F with (@fmap _ F);

repeat change (@fmap _ (@fmap _ F)) with (@fmap _ F)

| MBind _ ⇒

change F with (@mbind _ F);

repeat change (@mbind _ (@mbind _ F)) with (@mbind _ F)

| OMap _ ⇒

change F with (@omap _ F);

repeat change (@omap _ (@omap _ F)) with (@omap _ F)

| Alter _ _ _ ⇒

change F with (@alter _ _ _ F);

repeat change (@alter _ _ _ (@alter _ _ _ F)) with (@alter _ _ _ F)

end

end.

Ltac fold_classes_hyps H :=

repeat match type of H with

| context [ ?F ] ⇒

progress match type of F with

| FMap _ ⇒

change F with (@fmap _ F) in H;

repeat change (@fmap _ (@fmap _ F)) with (@fmap _ F) in H

| MBind _ ⇒

change F with (@mbind _ F) in H;

repeat change (@mbind _ (@mbind _ F)) with (@mbind _ F) in H

| OMap _ ⇒

change F with (@omap _ F) in H;

repeat change (@omap _ (@omap _ F)) with (@omap _ F) in H

| Alter _ _ _ ⇒

change F with (@alter _ _ _ F) in H;

repeat change (@alter _ _ _ (@alter _ _ _ F)) with (@alter _ _ _ F) in H

end

end.

Tactic Notation "csimpl" "in" hyp(H) :=

try (progress simpl in H; fold_classes_hyps H).

Tactic Notation "csimpl" := try (progress simpl; fold_classes).

Tactic Notation "csimpl" "in" "*" :=

repeat_on_hyps (fun H ⇒ csimpl in H); csimpl.

The tactic simplify_eq repeatedly substitutes, discriminates,
and injects equalities, and tries to contradict impossible inequalities.

Tactic Notation "simplify_eq" := repeat

match goal with

| H : _ ≠ _ |- _ ⇒ by case H; try clear H

| H : _ = _ → False |- _ ⇒ by case H; try clear H

| H : ?x = _ |- _ ⇒ subst x

| H : _ = ?x |- _ ⇒ subst x

| H : _ = _ |- _ ⇒ discriminate H

| H : _ ≡ _ |- _ ⇒ apply leibniz_equiv in H

| H : ?f _ = ?f _ |- _ ⇒ apply (inj f) in H

| H : ?f _ _ = ?f _ _ |- _ ⇒ apply (inj2 f) in H; destruct H

| H : ?f _ = ?f _ |- _ ⇒ progress injection H as H

| H : ?f _ _ = ?f _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ = ?f _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ = ?f _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ _ = ?f _ _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ _ _ = ?f _ _ _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?x = ?x |- _ ⇒ clear H

| H1 : ?o = Some ?x, H2 : ?o = Some ?y |- _ ⇒

assert (y = x) by congruence; clear H2

| H1 : ?o = Some ?x, H2 : ?o = None |- _ ⇒ congruence

| H : @existT ?A _ _ _ = existT _ _ |- _ ⇒

apply (Eqdep_dec.inj_pair2_eq_dec _ (decide_rel (=@{A}))) in H

end.

Tactic Notation "simplify_eq" "/=" :=

repeat (progress csimpl in × || simplify_eq).

Tactic Notation "f_equal" "/=" := csimpl in *; f_equal.

Ltac setoid_subst_aux R x :=

match goal with

| H : R x ?y |- _ ⇒

is_var x;

try match y with x _ ⇒ fail 2 end;

repeat match goal with

| |- context [ x ] ⇒ setoid_rewrite H

| H' : context [ x ] |- _ ⇒

try match H' with H ⇒ fail 2 end;

setoid_rewrite H in H'

end;

clear x H

end.

Ltac setoid_subst :=

repeat match goal with

| _ ⇒ progress simplify_eq/=

| H : @equiv ?A ?e ?x _ |- _ ⇒ setoid_subst_aux (@equiv A e) x

| H : @equiv ?A ?e _ ?x |- _ ⇒ symmetry in H; setoid_subst_aux (@equiv A e) x

end.

match goal with

| H : _ ≠ _ |- _ ⇒ by case H; try clear H

| H : _ = _ → False |- _ ⇒ by case H; try clear H

| H : ?x = _ |- _ ⇒ subst x

| H : _ = ?x |- _ ⇒ subst x

| H : _ = _ |- _ ⇒ discriminate H

| H : _ ≡ _ |- _ ⇒ apply leibniz_equiv in H

| H : ?f _ = ?f _ |- _ ⇒ apply (inj f) in H

| H : ?f _ _ = ?f _ _ |- _ ⇒ apply (inj2 f) in H; destruct H

| H : ?f _ = ?f _ |- _ ⇒ progress injection H as H

| H : ?f _ _ = ?f _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ = ?f _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ = ?f _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ _ = ?f _ _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?f _ _ _ _ _ _ = ?f _ _ _ _ _ _ |- _ ⇒ progress injection H as H

| H : ?x = ?x |- _ ⇒ clear H

| H1 : ?o = Some ?x, H2 : ?o = Some ?y |- _ ⇒

assert (y = x) by congruence; clear H2

| H1 : ?o = Some ?x, H2 : ?o = None |- _ ⇒ congruence

| H : @existT ?A _ _ _ = existT _ _ |- _ ⇒

apply (Eqdep_dec.inj_pair2_eq_dec _ (decide_rel (=@{A}))) in H

end.

Tactic Notation "simplify_eq" "/=" :=

repeat (progress csimpl in × || simplify_eq).

Tactic Notation "f_equal" "/=" := csimpl in *; f_equal.

Ltac setoid_subst_aux R x :=

match goal with

| H : R x ?y |- _ ⇒

is_var x;

try match y with x _ ⇒ fail 2 end;

repeat match goal with

| |- context [ x ] ⇒ setoid_rewrite H

| H' : context [ x ] |- _ ⇒

try match H' with H ⇒ fail 2 end;

setoid_rewrite H in H'

end;

clear x H

end.

Ltac setoid_subst :=

repeat match goal with

| _ ⇒ progress simplify_eq/=

| H : @equiv ?A ?e ?x _ |- _ ⇒ setoid_subst_aux (@equiv A e) x

| H : @equiv ?A ?e _ ?x |- _ ⇒ symmetry in H; setoid_subst_aux (@equiv A e) x

end.

f_equiv works on goals of the form f _ = f _, for any relation and any
number of arguments. It looks for an appropriate Proper instance, and applies
it. The tactic is somewhat limited, since it cannot be used to backtrack on
the Proper instances that has been found. To that end, we try to avoid the
trivial instance in which the resulting goals have an eq. More generally,
we try to "maintain" the relation of the current goal. For example,
when having Proper (equiv ==> dist) f and Proper (dist ==> dist) f, it will
favor the second because the relation (dist) stays the same.

Ltac f_equiv :=

match goal with

| |- pointwise_relation _ _ _ _ ⇒ intros ?

| |- ?R (match ?x with _ ⇒ _ end) (match ?x with _ ⇒ _ end) ⇒

destruct x

| H : ?R ?x ?y |- ?R2 (match ?x with _ ⇒ _ end) (match ?y with _ ⇒ _ end) ⇒

destruct H

| |- ?R (?f _) (?f _) ⇒ simple apply (_ : Proper (R ==> R) f)

| |- ?R (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R) f)

| |- ?R (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R) f)

| |- ?R (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R ==> R) f)

| |- ?R (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R ==> R ==> R) f)

| |- (?R _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ ==> R _) f)

| |- (?R _ _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| H : _ ?f ?g |- ?R (?f ?x) (?g ?x) ⇒ solve [simple apply H]

| H : _ ?f ?g |- ?R (?f ?x ?y) (?g ?x ?y) ⇒ solve [simple apply H]

| |- ?R (?f _) _ ⇒ simple apply (_ : Proper (_ ==> R) f)

| |- ?R (?f _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> R) f)

| |- ?R (?f _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> R) f)

| |- ?R (?f _ _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> _ ==> R) f)

| |- ?R (?f _ _ _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> _ ==> _ ==> R) f)

end;

try match goal with |- _ ?x ?x ⇒ simple apply reflexivity end.

Tactic Notation "f_equiv" "/=" := csimpl in *; f_equiv.

match goal with

| |- pointwise_relation _ _ _ _ ⇒ intros ?

| |- ?R (match ?x with _ ⇒ _ end) (match ?x with _ ⇒ _ end) ⇒

destruct x

| H : ?R ?x ?y |- ?R2 (match ?x with _ ⇒ _ end) (match ?y with _ ⇒ _ end) ⇒

destruct H

| |- ?R (?f _) (?f _) ⇒ simple apply (_ : Proper (R ==> R) f)

| |- ?R (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R) f)

| |- ?R (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R) f)

| |- ?R (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R ==> R) f)

| |- ?R (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R ==> R ==> R ==> R ==> R ==> R) f)

| |- (?R _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ ==> R _) f)

| |- (?R _ _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _) (?f _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _) (?f _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _) (?f _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _ _) (?f _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| |- (?R _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ ==> R _ ==> R _ ==> R _ ==> R _ ==> R _) f)

| |- (?R _ _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _ ==> R _ _) f)

| |- (?R _ _ _) (?f _ _ _ _ _) (?f _ _ _ _ _) ⇒ simple apply (_ : Proper (R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _ ==> R _ _ _) f)

| H : _ ?f ?g |- ?R (?f ?x) (?g ?x) ⇒ solve [simple apply H]

| H : _ ?f ?g |- ?R (?f ?x ?y) (?g ?x ?y) ⇒ solve [simple apply H]

| |- ?R (?f _) _ ⇒ simple apply (_ : Proper (_ ==> R) f)

| |- ?R (?f _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> R) f)

| |- ?R (?f _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> R) f)

| |- ?R (?f _ _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> _ ==> R) f)

| |- ?R (?f _ _ _ _ _) _ ⇒ simple apply (_ : Proper (_ ==> _ ==> _ ==> _ ==> _ ==> R) f)

end;

try match goal with |- _ ?x ?x ⇒ simple apply reflexivity end.

Tactic Notation "f_equiv" "/=" := csimpl in *; f_equiv.

The tactic solve_proper_unfold unfolds the first head symbol, so that
we proceed by repeatedly using f_equiv.

Ltac solve_proper_unfold :=

try lazymatch goal with

| |- ?R ?t1 ?t2 ⇒

let h1 := get_head t1 in

let h2 := get_head t2 in

unify h1 h2;

unfold h1

end.

try lazymatch goal with

| |- ?R ?t1 ?t2 ⇒

let h1 := get_head t1 in

let h2 := get_head t2 in

unify h1 h2;

unfold h1

end.

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 :=

intros;

repeat lazymatch goal with

| |- Proper _ _ ⇒ intros ???

| |- (_ ==> _)%signature _ _ ⇒ intros ???

| |- pointwise_relation _ _ _ _ ⇒ intros ?

| |- ?R ?f _ ⇒

let f' := constr:(λ x, f x) in

intros ?; intros

end; simplify_eq;

(solve_proper_unfold + idtac); simpl.

intros;

repeat lazymatch goal with

| |- Proper _ _ ⇒ intros ???

| |- (_ ==> _)%signature _ _ ⇒ intros ???

| |- pointwise_relation _ _ _ _ ⇒ intros ?

| |- ?R ?f _ ⇒

let f' := constr:(λ x, f x) in

intros ?; intros

end; simplify_eq;

(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;

solve [repeat first [eassumption | tac ()] ].

solve_proper_prepare;

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,
and then reverts them.

Ltac intros_revert tac :=

lazymatch goal with

| |- ∀ _, _ ⇒ let H := fresh in intro H; intros_revert tac; revert H

| |- _ ⇒ tac

end.

lazymatch goal with

| |- ∀ _, _ ⇒ let H := fresh in intro H; intros_revert tac; revert H

| |- _ ⇒ tac

end.

The tactic iter tac l runs tac x for each element x ∈ l until tac x
succeeds. If it does not suceed for any element of the generated list, the whole
tactic wil fail.

Tactic Notation "iter" tactic(tac) tactic(l) :=

let rec go l :=

match l with ?x :: ?l ⇒ tac x || go l end in go l.

let rec go l :=

match l with ?x :: ?l ⇒ tac x || go l end in go l.

Given H : A_1 → ... → A_n → B (where each A_i is non-dependent), the
tactic feed tac H tac_by creates a subgoal for each A_i and calls tac p
with the generated proof p of B.

Tactic Notation "feed" tactic(tac) constr(H) :=

let rec go H :=

let T := type of H in

lazymatch eval hnf in T with

| ?T1 → ?T2 ⇒

let HT1 := fresh "feed" in assert T1 as HT1;

[| go (H HT1); clear HT1 ]

| ?T1 ⇒ tac H

end in go H.

let rec go H :=

let T := type of H in

lazymatch eval hnf in T with

| ?T1 → ?T2 ⇒

let HT1 := fresh "feed" in assert T1 as HT1;

[| go (H HT1); clear HT1 ]

| ?T1 ⇒ tac H

end in go H.

The tactic efeed tac H is similar to feed, but it also instantiates
dependent premises of H with evars.

Tactic Notation "efeed" constr(H) "using" tactic3(tac) "by" tactic3 (bytac) :=

let rec go H :=

let T := type of H in

lazymatch eval hnf in T with

| ?T1 → ?T2 ⇒

let HT1 := fresh "feed" in assert T1 as HT1;

[bytac | go (H HT1); clear HT1 ]

| ?T1 → _ ⇒

let e := mk_evar T1 in

go (H e)

| ?T1 ⇒ tac H

end in go H.

Tactic Notation "efeed" constr(H) "using" tactic3(tac) :=

efeed H using tac by idtac.

let rec go H :=

let T := type of H in

lazymatch eval hnf in T with

| ?T1 → ?T2 ⇒

let HT1 := fresh "feed" in assert T1 as HT1;

[bytac | go (H HT1); clear HT1 ]

| ?T1 → _ ⇒

let e := mk_evar T1 in

go (H e)

| ?T1 ⇒ tac H

end in go H.

Tactic Notation "efeed" constr(H) "using" tactic3(tac) :=

efeed H using tac by idtac.

The following variants of pose proof, specialize, inversion, and
destruct, use the feed tactic before invoking the actual tactic.

Tactic Notation "feed" "pose" "proof" constr(H) "as" ident(H') :=

feed (fun p ⇒ pose proof p as H') H.

Tactic Notation "feed" "pose" "proof" constr(H) :=

feed (fun p ⇒ pose proof p) H.

Tactic Notation "efeed" "pose" "proof" constr(H) "as" ident(H') :=

efeed H using (fun p ⇒ pose proof p as H').

Tactic Notation "efeed" "pose" "proof" constr(H) :=

efeed H using (fun p ⇒ pose proof p).

Tactic Notation "feed" "specialize" hyp(H) :=

feed (fun p ⇒ specialize p) H.

Tactic Notation "efeed" "specialize" hyp(H) :=

efeed H using (fun p ⇒ specialize p).

Tactic Notation "feed" "inversion" constr(H) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; inversion H') H.

Tactic Notation "feed" "inversion" constr(H) "as" simple_intropattern(IP) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; inversion H' as IP) H.

Tactic Notation "feed" "destruct" constr(H) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; destruct H') H.

Tactic Notation "feed" "destruct" constr(H) "as" simple_intropattern(IP) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; destruct H' as IP) H.

feed (fun p ⇒ pose proof p as H') H.

Tactic Notation "feed" "pose" "proof" constr(H) :=

feed (fun p ⇒ pose proof p) H.

Tactic Notation "efeed" "pose" "proof" constr(H) "as" ident(H') :=

efeed H using (fun p ⇒ pose proof p as H').

Tactic Notation "efeed" "pose" "proof" constr(H) :=

efeed H using (fun p ⇒ pose proof p).

Tactic Notation "feed" "specialize" hyp(H) :=

feed (fun p ⇒ specialize p) H.

Tactic Notation "efeed" "specialize" hyp(H) :=

efeed H using (fun p ⇒ specialize p).

Tactic Notation "feed" "inversion" constr(H) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; inversion H') H.

Tactic Notation "feed" "inversion" constr(H) "as" simple_intropattern(IP) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; inversion H' as IP) H.

Tactic Notation "feed" "destruct" constr(H) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; destruct H') H.

Tactic Notation "feed" "destruct" constr(H) "as" simple_intropattern(IP) :=

feed (fun p ⇒ let H':=fresh in pose proof p as H'; destruct H' as IP) H.

The block definitions are taken from Coq.Program.Equality and can be used
by tactics to separate their goal from hypotheses they generalize over.

Definition block {A : Type} (a : A) := a.

Ltac block_goal := match goal with [ |- ?T ] ⇒ change (block T) end.

Ltac unblock_goal := unfold block in ×.

Ltac block_goal := match goal with [ |- ?T ] ⇒ change (block T) end.

Ltac unblock_goal := unfold block in ×.

learn_hyp p as H and learn_hyp p, where p is a proof of P,
add P to the context and fail if P already exists in the context.
This is a simple form of the learning pattern. These tactics are
inspired by Program.Tactics.add_hypothesis.

Tactic Notation "learn_hyp" constr(p) "as" ident(H') :=

let P := type of p in

match goal with

| H : P |- _ ⇒ fail 1

| _ ⇒ pose proof p as H'

end.

Tactic Notation "learn_hyp" constr(p) :=

let H := fresh in learn_hyp p as H.

let P := type of p in

match goal with

| H : P |- _ ⇒ fail 1

| _ ⇒ pose proof p as H'

end.

Tactic Notation "learn_hyp" constr(p) :=

let H := fresh in learn_hyp p as H.

The tactic select pat tac finds the last (i.e., bottommost) hypothesis
matching pat and passes it to the continuation tac. Its main advantage over
using match goal with directly is that it is shorter. If pat matches
multiple hypotheses and tac fails, then select tac will not backtrack on
subsequent matching hypotheses.
The tactic select is written in CPS and does not return the name of the
hypothesis due to limitations in the Ltac1 tactic runtime (see
https://gitter.im/coq/coq?at=5e96c82f85b01628f04bbb89).

Tactic Notation "select" open_constr(pat) tactic3(tac) :=

lazymatch goal with

lazymatch goal with

Before running tac on the hypothesis H we must first unify the
pattern pat with the term it matched against. This forces every evar
coming from pat (and in particular from the holes _ it contains and
from the implicit arguments it uses) to be instantiated. If we do not do
so then shelved goals are produced for every such evar.

| H : pat |- _ ⇒ let T := (type of H) in unify T pat; tac H

end.

end.

select_revert reverts the first hypothesis matching pat.

Tactic Notation "revert" "select" open_constr(pat) := select pat (fun H ⇒ revert H).

Tactic Notation "rename" "select" open_constr(pat) "into" ident(name) :=

select pat (fun H ⇒ rename H into name).

Tactic Notation "rename" "select" open_constr(pat) "into" ident(name) :=

select pat (fun H ⇒ rename H into name).

Coq's firstorder tactic fails or loops on rather small goals already. In
particular, on those generated by the tactic unfold_elem_ofs which is used
to solve propositions on sets. The naive_solver tactic implements an
ad-hoc and incomplete firstorder-like solver using Ltac's backtracking
mechanism. The tactic suffers from the following limitations:
We use a counter to make the search breath first. Breath first search ensures
that a minimal number of hypotheses is instantiated, and thus reduced the
posibility that an evar remains unresolved.
Despite these limitations, it works much better than Coq's firstorder tactic
for the purposes of this development. This tactic either fails or proves the
goal.

- It might leave unresolved evars as Ltac provides no way to detect that.
- To avoid the tactic becoming too slow, we allow a universally quantified hypothesis to be instantiated only once during each search path.
- It does not perform backtracking on instantiation of universally quantified assumptions.

Lemma forall_and_distr (A : Type) (P Q : A → Prop) :

(∀ x, P x ∧ Q x) ↔ (∀ x, P x) ∧ (∀ x, Q x).

Proof. firstorder. Qed.

(∀ x, P x ∧ Q x) ↔ (∀ x, P x) ∧ (∀ x, Q x).

Proof. firstorder. Qed.

The tactic no_new_unsolved_evars tac executes tac and fails if it
creates any new evars. This trick is by Jonathan Leivent, see:
https://coq.inria.fr/bugs/show_bug.cgi?id=3872

Ltac no_new_unsolved_evars tac := exact ltac:(tac).

Tactic Notation "naive_solver" tactic(tac) :=

unfold iff, not in *;

repeat match goal with

| H : context [∀ _, _ ∧ _ ] |- _ ⇒

repeat setoid_rewrite forall_and_distr in H; revert H

end;

let rec go n :=

repeat match goal with

| |- _ ⇒ fast_done

| |- ∀ _, _ ⇒ intro

| H : False |- _ ⇒ destruct H

| H : _ ∧ _ |- _ ⇒

let H1 := fresh in let H2 := fresh in

destruct H as [H1 H2]; try clear H

| H : ∃ _, _ |- _ ⇒

let x := fresh in let Hx := fresh in

destruct H as [x Hx]; try clear H

| H : ?P → ?Q, H2 : ?P |- _ ⇒ specialize (H H2)

| H : Is_true (bool_decide _) |- _ ⇒ apply (bool_decide_unpack _) in H

| H : Is_true (_ && _) |- _ ⇒ apply andb_True in H; destruct H

| |- _ ⇒ progress simplify_eq/=

| |- _ ∧ _ ⇒ split

| |- Is_true (bool_decide _) ⇒ apply (bool_decide_pack _)

| |- Is_true (_ && _) ⇒ apply andb_True; split

| H : _ ∨ _ |- _ ⇒

let H1 := fresh in destruct H as [H1|H1]; try clear H

| H : Is_true (_ || _) |- _ ⇒

apply orb_True in H; let H1 := fresh in destruct H as [H1|H1]; try clear H

| |- _ ⇒ solve [tac]

end;

match goal with

| |- ∃ x, _ ⇒ no_new_unsolved_evars ltac:(eexists; go n)

| |- _ ∨ _ ⇒ first [left; go n | right; go n]

| |- Is_true (_ || _) ⇒ apply orb_True; first [left; go n | right; go n]

| _ ⇒

lazymatch n with

| S ?n' ⇒

match goal with

| H : _ → _ |- _ ⇒

is_non_dependent H;

no_new_unsolved_evars

ltac:(first [eapply H | efeed pose proof H]; clear H; go n')

end

end

end

in iter (fun n' ⇒ go n') (eval compute in (seq 1 6)).

Tactic Notation "naive_solver" := naive_solver eauto.