From 6133a43c30e03656696a897bcedaf0cfb2cec70d Mon Sep 17 00:00:00 2001
From: Matthieu Sozeau
Date: Fri, 20 Jun 2014 16:03:52 +0200
Subject: Allow more relaxed conversion between the types of the two terms of a
 rewrite equation, fix uncaught exception in setoid_rewrite (bug #3336).

---
 tactics/rewrite.ml            | 16 +++++++---------
 test-suite/bugs/closed/3336.v |  9 +++++++++
 test-suite/bugs/opened/3336.v |  6 ------
 3 files changed, 16 insertions(+), 15 deletions(-)
 create mode 100644 test-suite/bugs/closed/3336.v
 delete mode 100644 test-suite/bugs/opened/3336.v

diff --git a/tactics/rewrite.ml b/tactics/rewrite.ml
index d7091b5d03..8794557ef6 100644
--- a/tactics/rewrite.ml
+++ b/tactics/rewrite.ml
@@ -444,7 +444,7 @@ let evd_convertible env evd x y =
   with e when Errors.noncritical e -> false
 
 let convertible env evd x y =
-  Reductionops.is_conv env evd x y
+  Reductionops.is_conv_leq env evd x y
 
 type hypinfo = {
   cl : clausenv;
@@ -634,13 +634,9 @@ let unify_eqn env (sigma, cstrs) hypinfo by t =
 	  let ty1 = Retyping.get_type_of env'.env env'.evd c1
 	  and ty2 = Retyping.get_type_of env'.env env'.evd c2
 	  in
-	    if convertible env env'.evd ty1 ty2 then 
-	      (* (if occur_meta_or_existential prf then *)
-		(hypinfo := refresh_hypinfo env env'.evd !hypinfo;
-		 env'.evd, prf, c1, c2, car, rel)
-	       (* else (\** Evars have been solved, we can go back to the initial evd, *)
-	       (* 		but keep the potential refinement of existing evars. *\) *)
-	       (* 	  env'.evd, prf, c1, c2, car, rel) *)
+	    if convertible env env'.evd ty2 ty1 then 
+	      (hypinfo := refresh_hypinfo env env'.evd !hypinfo;
+	       env'.evd, prf, c1, c2, car, rel)
 	    else raise Reduction.NotConvertible
     in
     let evars = evd', cstrs in
@@ -655,7 +651,9 @@ let unify_eqn env (sigma, cstrs) hypinfo by t =
 	  let evars, rel' = poly_inverse !hypinfo.sort env evars car rel in
 	    evars, (prf, (car, rel', c2, c1))
     in Some (evd, res)
-  with e when Class_tactics.catchable e -> None
+  with 
+  | e when Class_tactics.catchable e -> None
+  | Reduction.NotConvertible -> None
 
 type rewrite_flags = { under_lambdas : bool; on_morphisms : bool }
 
diff --git a/test-suite/bugs/closed/3336.v b/test-suite/bugs/closed/3336.v
new file mode 100644
index 0000000000..dc358c6004
--- /dev/null
+++ b/test-suite/bugs/closed/3336.v
@@ -0,0 +1,9 @@
+Require Import Setoid.
+
+Goal forall x y : Type, x = y -> x = y.
+intros x y H.
+setoid_rewrite H.
+reflexivity.
+Defined.
+(* Toplevel input, characters 0-16:
+Anomaly: Uncaught exception Reduction.NotConvertible(_). Please report. *)
diff --git a/test-suite/bugs/opened/3336.v b/test-suite/bugs/opened/3336.v
deleted file mode 100644
index d469a13a34..0000000000
--- a/test-suite/bugs/opened/3336.v
+++ /dev/null
@@ -1,6 +0,0 @@
-Require Import Setoid.
-Goal forall x y : Type, x = y -> x = y.
-intros x y H.
-Fail setoid_rewrite H.
-(* Toplevel input, characters 0-16:
-Anomaly: Uncaught exception Reduction.NotConvertible(_). Please report. *)
-- 
cgit v1.2.3