From 32e18eb2ec0d44e4265f44d2f3f51daa7d67e9c0 Mon Sep 17 00:00:00 2001
From: herbelin
Date: Sat, 18 Jun 2011 20:35:32 +0000
Subject: Relaxed the constraint introduced in r14190 that froze the existing
 evars when rewriting. Use it for autorewrite and subst. Accept evars
 instantiation in multi_rewrite so that rewrite alone remains compatible (it
 is used in contribs, e.g. Godel, in places where it does not seem absurd to
 allow it), but there are no good reason for it. Comments welcome. + addition
 of some tests for rewriting (one being related to commit 14217)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@14222 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 test-suite/bugs/closed/shouldsucceed/1416.v |  7 +++++--
 test-suite/success/autorewrite.v            | 29 +++++++++++++++++++++++++++++
 test-suite/success/autorewritein.v          | 23 -----------------------
 test-suite/success/rewrite.v                | 11 +++++++++++
 4 files changed, 45 insertions(+), 25 deletions(-)
 create mode 100644 test-suite/success/autorewrite.v
 delete mode 100644 test-suite/success/autorewritein.v

(limited to 'test-suite')

diff --git a/test-suite/bugs/closed/shouldsucceed/1416.v b/test-suite/bugs/closed/shouldsucceed/1416.v
index da67d9b04f..ee09200573 100644
--- a/test-suite/bugs/closed/shouldsucceed/1416.v
+++ b/test-suite/bugs/closed/shouldsucceed/1416.v
@@ -1,3 +1,8 @@
+(* In 8.1 autorewrite used to raised an anomaly here *)
+(* After resolution of the bug, autorewrite succeeded *)
+(* From forthcoming 8.4, autorewrite is forbidden to instantiate *)
+(* evars, so the new test just checks it is not an anomaly *)
+
 Set Implicit Arguments.
 
 Record Place (Env A: Type) : Type := {
@@ -22,6 +27,4 @@ Lemma autorewrite_raise_anomaly: forall (Env A:Type) (e: Env) (p:Place Env A),
 Proof.
   intros Env A e p; eapply ex_intro.
   autorewrite with placeeq. (* Here is the bug *)
-  auto.
-Qed.
 
diff --git a/test-suite/success/autorewrite.v b/test-suite/success/autorewrite.v
new file mode 100644
index 0000000000..5e9064f8af
--- /dev/null
+++ b/test-suite/success/autorewrite.v
@@ -0,0 +1,29 @@
+Variable Ack : nat -> nat -> nat.
+
+Axiom Ack0 : forall m : nat, Ack 0 m = S m.
+Axiom Ack1 : forall n : nat, Ack (S n) 0 = Ack n 1.
+Axiom Ack2 : forall n m : nat, Ack (S n) (S m) = Ack n (Ack (S n) m).
+
+Hint Rewrite Ack0 Ack1 Ack2 : base0.
+
+Lemma ResAck0 : (Ack 2 2 = 7 -> False) -> False.
+Proof.
+  intros.
+  autorewrite with base0 in H using try (apply H; reflexivity).
+Qed.
+
+Lemma ResAck1 : forall H:(Ack 2 2 = 7 -> False), True -> False.
+Proof.
+  intros.
+  autorewrite with base0 in *.
+    apply H;reflexivity.
+Qed.
+
+(* Check autorewrite does not solve existing evars *)
+(* See discussion started by A. Chargueraud in Oct 2010 on coqdev *)
+
+Hint Rewrite <- plus_n_O : base1.
+Goal forall y, exists x, y+x = y.
+eexists. autorewrite with base1.
+Fail reflexivity.
+
diff --git a/test-suite/success/autorewritein.v b/test-suite/success/autorewritein.v
deleted file mode 100644
index 68f2f7ce73..0000000000
--- a/test-suite/success/autorewritein.v
+++ /dev/null
@@ -1,23 +0,0 @@
-Variable Ack : nat -> nat -> nat.
-
-Axiom Ack0 : forall m : nat, Ack 0 m = S m.
-Axiom Ack1 : forall n : nat, Ack (S n) 0 = Ack n 1.
-Axiom Ack2 : forall n m : nat, Ack (S n) (S m) = Ack n (Ack (S n) m).
-
-Hint Rewrite Ack0 Ack1 Ack2 : base0.
-
-Lemma ResAck0 : (Ack 2 2 = 7 -> False) -> False.
-Proof.
-  intros.
-  autorewrite with base0 in H using try (apply H; reflexivity).
-Qed.
-
-Lemma ResAck1 : forall H:(Ack 2 2 = 7 -> False), True -> False.
-Proof.
-  intros.
-  autorewrite with base0 in *.
-    apply H;reflexivity.
-Qed.
-
-
-
diff --git a/test-suite/success/rewrite.v b/test-suite/success/rewrite.v
index 3bce52fe78..3d49d3cf93 100644
--- a/test-suite/success/rewrite.v
+++ b/test-suite/success/rewrite.v
@@ -108,3 +108,14 @@ intros.
 rewrite (H _).
 reflexivity.
 Qed.
+
+(* Example of rewriting of a degenerated pattern using the right-most
+   argument of the goal. This is sometimes used in contribs, even if
+   ad hoc. Here, we have the extra requirement that checking types
+   needs delta-conversion *)
+
+Axiom s : forall (A B : Type) (p : A * B), p = (fst p, snd p).
+Definition P := (nat * nat)%type.
+Goal forall x:P, x = x.
+intros. rewrite s.
+
-- 
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