%expect-rr: fix the computation of the overall number of conflicts

On a grammar such as

   exp: "num" | "num" | "num"

we currently report only one RR conflict, instead of two.

This bug is present since the origins of Bison

    commit 08089d5d35ece0c7d41659cc1bc09638e2abb151
    Author: David MacKenzie <djm@djmnet.org>
    Date:   Tue Apr 20 05:42:52 1993 +0000

       Initial revision

and was preserved in

    commit 676385e29c4aedfc05d20daf1ef20cd4ccc84856
    Author: Paul Hilfinger <Hilfinger@CS.Berkeley.EDU>
    Date:   Fri Jun 28 02:26:44 2002 +0000

       Initial check-in introducing experimental GLR parsing.  See entry in
       ChangeLog dated 2002-06-27 from Paul Hilfinger for details.

See
https://lists.gnu.org/archive/html/bison-patches/2018-11/msg00011.html

* src/conflicts.h, src/conflicts.c (count_state_rr_conflicts)
(count_rr_conflicts): Use only the correct count of conflicts.
* tests/glr-regression.at: Fix expectations.

1 files changed, 14 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 20127a74..9309de64 100644
--- a/NEWS
+++ b/NEWS
@@ -26,6 +26,20 @@ GNU Bison NEWS
   The use of the %error-verbose directive is deprecated in favor of "%define
   parse.error verbose" since Bison 3.0, but no warning was issued.
 
+** Bug fixes
+
+*** Incorrect number of reduce-reduce conflicts
+
+  On a grammar such as
+
+     exp: "num" | "num" | "num"
+
+  bison used report a single RR conflict, instead of two.  This is now
+  fixed.  This was the oldest (known) bug in Bison: it was there when Bison
+  was entered in the RCS version control system, in December 1987.
+
+  Some grammar files might have to adjust their %expect-rr.
+
 * Noteworthy changes in release 3.2.2 (2018-11-21) [stable]
 
 ** Bug fixes