From 4e18be02a03ab478125aa6f08b30e738c3568572 Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Fri, 23 Feb 2018 14:12:12 +0100
Subject: Fixes #6821 (bug in protecting notation printing from infinite
 eta-expansion).

More precisely when matching

   "f t" with "(fun ?x => .. ((fun ?x' => ?y) ?z') ..) ?z"

do not allow expansion of f since otherwise, we recursively have to
match "f t" with the same pattern.
---
 interp/notation_ops.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'interp/notation_ops.ml')

diff --git a/interp/notation_ops.ml b/interp/notation_ops.ml
index c65f4785ef..9bc41a996b 100644
--- a/interp/notation_ops.ml
+++ b/interp/notation_ops.ml
@@ -1132,7 +1132,7 @@ let rec match_ inner u alp metas sigma a1 a2 =
 	else f1,l1, f2, l2 in
       let may_use_eta = does_not_come_from_already_eta_expanded_var f1 in
       List.fold_left2 (match_ may_use_eta u alp metas)
-        (match_in u alp metas sigma f1 f2) l1 l2
+        (match_hd u alp metas sigma f1 f2) l1 l2
   | GLambda (na1,bk1,t1,b1), NLambda (na2,t2,b2) ->
      match_extended_binders false u alp metas na1 na2 bk1 t1 (match_in u alp metas sigma t1 t2) b1 b2
   | GProd (na1,bk1,t1,b1), NProd (na2,t2,b2) ->
-- 
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