From 378422bcb7de688ac201a70668a3e33b88bdae42 Mon Sep 17 00:00:00 2001
From: Cyril Cohen
Date: Mon, 6 Apr 2020 01:03:15 +0200
Subject: Make `all2` better wrt the guard condition

fixes #469
---
 CHANGELOG_UNRELEASED.md  |  3 +++
 mathcomp/ssreflect/seq.v | 10 +++++-----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG_UNRELEASED.md b/CHANGELOG_UNRELEASED.md
index 96ec16c..aa3983e 100644
--- a/CHANGELOG_UNRELEASED.md
+++ b/CHANGELOG_UNRELEASED.md
@@ -143,6 +143,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
     `ssrnat.mc_1_10` module. One may compile proofs compatible with the version
     1.10 in newer versions by using this module.
 
+- The definition of `all2` was slightly altered for a better interaction with
+  the guard condition (#469)
+
 ### Renamed
 
 - `real_lerP` -> `real_leP`
diff --git a/mathcomp/ssreflect/seq.v b/mathcomp/ssreflect/seq.v
index dca4136..aca2b77 100644
--- a/mathcomp/ssreflect/seq.v
+++ b/mathcomp/ssreflect/seq.v
@@ -2634,7 +2634,7 @@ Prenex Implicits mask map pmap foldr foldl scanl pairmap.
 
 Section Zip.
 
-Variables S T : Type.
+Variables (S T : Type) (r : S -> T -> bool).
 
 Fixpoint zip (s : seq S) (t : seq T) {struct t} :=
   match s, t with
@@ -2645,10 +2645,10 @@ Fixpoint zip (s : seq S) (t : seq T) {struct t} :=
 Definition unzip1 := map (@fst S T).
 Definition unzip2 := map (@snd S T).
 
-Fixpoint all2 (r : S -> T -> bool) s t :=
+Fixpoint all2 s t :=
   match s, t with
   | [::], [::] => true
-  | x :: s, y :: t => r x y && all2 r s t
+  | x :: s, y :: t => r x y && all2 s t
   | _, _ => false
   end.
 
@@ -2696,8 +2696,8 @@ move: s t; apply: seq_ind2 => //= x y s t eq_sz IHs.
 by rewrite !rev_cons IHs zip_rcons ?size_rev.
 Qed.
 
-Lemma all2E r s t :
-  all2 r s t = (size s == size t) && all [pred xy | r xy.1 xy.2] (zip s t).
+Lemma all2E s t :
+  all2 s t = (size s == size t) && all [pred xy | r xy.1 xy.2] (zip s t).
 Proof. by elim: s t => [|x s IHs] [|y t] //=; rewrite IHs andbCA. Qed.
 
 End Zip.
-- 
cgit v1.2.3


From b4673a3f6d06a4ff38789fd82f33dd517186eb44 Mon Sep 17 00:00:00 2001
From: Cyril Cohen
Date: Fri, 10 Apr 2020 10:55:30 +0200
Subject: adding guard conditions check to the test_suite

---
 mathcomp/Make.test-suite         | 1 +
 mathcomp/test_suite/test_guard.v | 6 ++++++
 2 files changed, 7 insertions(+)
 create mode 100644 mathcomp/test_suite/test_guard.v

diff --git a/mathcomp/Make.test-suite b/mathcomp/Make.test-suite
index 99d8289..2be741b 100644
--- a/mathcomp/Make.test-suite
+++ b/mathcomp/Make.test-suite
@@ -1,5 +1,6 @@
 test_suite/hierarchy_test.v
 test_suite/test_ssrAC.v
+test_suite/test_guard.v
 
 -I .
 -R . mathcomp
diff --git a/mathcomp/test_suite/test_guard.v b/mathcomp/test_suite/test_guard.v
new file mode 100644
index 0000000..1e93a2c
--- /dev/null
+++ b/mathcomp/test_suite/test_guard.v
@@ -0,0 +1,6 @@
+From mathcomp Require Import all_ssreflect.
+
+Inductive tree := Node { children : seq tree }.
+
+Fixpoint eq_tree (x y : tree) {struct x} : bool :=
+  all2 eq_tree (children x) (children y).
-- 
cgit v1.2.3