Hack for fixing bug #2172 (see explanations in file rewrite-2172.v).

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@13167 85f007b7-540e-0410-9357-904b9bb8a0f7

1 files changed, 21 insertions, 0 deletions

diff --git a/test-suite/output/rewrite-2172.v b/test-suite/output/rewrite-2172.v
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+++ b/test-suite/output/rewrite-2172.v
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+(* This checks an error message as reported in bug #2172 *)
+
+Axiom axiom : forall (E F : nat), E = F.
+Lemma test : forall (E F : nat), E = F.
+Proof.
+  intros.
+(* This used to raise the following non understandable error message:
+
+   Error: Unable to find an instance for the variable x
+
+   The reason this error was that rewrite generated the proof
+
+   "eq_ind ?A ?x ?P ? ?y (axiom ?E ?F)"
+
+   and the equation ?x=?E was solved in the way ?E:=?x leaving ?x
+   unresolved. A stupid hack for solve this consisted in ordering
+   meta=meta equations the other way round (with most recent evars
+   instantiated first - since they are assumed to come first from the
+   user in rewrite/induction/destruct calls).
+*)
+  Fail rewrite <- axiom.