From 928d186f5dcc649793ea9f3dd8f880d93786dfe7 Mon Sep 17 00:00:00 2001
From: herbelin
Date: Sun, 13 Jun 2010 11:09:51 +0000
Subject: Fixed bug #2314 (inversion using not checking the correctness of its
 arguments enough)

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@13126 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 proofs/clenv.ml                | 6 +++---
 proofs/clenv.mli               | 2 ++
 tactics/leminv.ml              | 5 ++++-
 test-suite/success/Inversion.v | 7 +++++++
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/proofs/clenv.ml b/proofs/clenv.ml
index dade69865c..8b4b41219b 100644
--- a/proofs/clenv.ml
+++ b/proofs/clenv.ml
@@ -440,11 +440,11 @@ let clenv_match_args bl clenv =
 	  clenv_assign_binding clenv k c)
       clenv bl
 
+exception NoSuchBinding
+
 let clenv_constrain_last_binding c clenv =
   let all_mvs = collect_metas clenv.templval.rebus in
-  let k =
-    try list_last all_mvs
-    with Failure _ -> anomaly "clenv_constrain_with_bindings" in
+  let k = try list_last all_mvs with Failure _ -> raise NoSuchBinding in
   clenv_assign_binding clenv k c
 
 let clenv_constrain_dep_args hyps_only bl clenv =
diff --git a/proofs/clenv.mli b/proofs/clenv.mli
index 209024c9c4..9a93adc440 100644
--- a/proofs/clenv.mli
+++ b/proofs/clenv.mli
@@ -85,6 +85,8 @@ type arg_bindings = constr explicit_bindings
 val clenv_independent : clausenv -> metavariable list
 val clenv_missing : clausenv -> metavariable list
 
+(** for the purpose of inversion tactics *)
+exception NoSuchBinding
 val clenv_constrain_last_binding : constr -> clausenv -> clausenv
 
 (** defines metas corresponding to the name of the bindings *)
diff --git a/tactics/leminv.ml b/tactics/leminv.ml
index abb114d917..6795b4817a 100644
--- a/tactics/leminv.ml
+++ b/tactics/leminv.ml
@@ -288,7 +288,10 @@ let lemInv id c gls =
     let clause = clenv_constrain_last_binding (mkVar id) clause in
     Clenvtac.res_pf clause ~allow_K:true gls
   with
-    |  UserError (a,b) ->
+    | NoSuchBinding ->
+	errorlabstrm ""
+	  (hov 0 (pr_constr c ++ spc () ++ str "does not refer to an inversion lemma."))
+    | UserError (a,b) ->
 	 errorlabstrm "LemInv"
 	   (str "Cannot refine current goal with the lemma " ++
 	      pr_lconstr_env (Global.env()) c)
diff --git a/test-suite/success/Inversion.v b/test-suite/success/Inversion.v
index 5091b44c1c..043d949c91 100644
--- a/test-suite/success/Inversion.v
+++ b/test-suite/success/Inversion.v
@@ -129,3 +129,10 @@ Proof.
    an inconsistent state that disturbed "inversion" *)
 intros. inversion H.
 Abort.
+
+(* Bug #2314 (simplified): check that errors do not show as anomalies *)
+
+Goal True -> True.
+intro.
+Fail inversion H using False.
+Fail inversion foo using True_ind.
-- 
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