From 8358090292e21c61a583da542bad9099ad65f355 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 20 Jan 2021 18:30:16 -0800
Subject: [PATCH 01/26] c: port to HP-UX 11.23

Problem reported by Albert Chin in:
https://lists.gnu.org/r/bug-bison/2021-01/msg00029.html
* data/skeletons/c.m4 (b4_c99_int_type_define):
Work around HP-UX bug.
---
 NEWS                |  3 +++
 data/skeletons/c.m4 | 12 ++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/NEWS b/NEWS
index e3633e05..1fd12f9f 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,9 @@ GNU Bison NEWS
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
+** Bug fixes
+
+*** C-language parsers now work around quirks of HP-UX 11.23 (2003).
 
 * Noteworthy changes in release 3.7.4 (2020-11-14) [stable]
 
diff --git a/data/skeletons/c.m4 b/data/skeletons/c.m4
index 07148ef8..14a16a9d 100644
--- a/data/skeletons/c.m4
+++ b/data/skeletons/c.m4
@@ -242,6 +242,18 @@ typedef int_least16_t yytype_int16;
 typedef short yytype_int16;
 #endif
 
+/* Work around bug in HP-UX 11.23, which defines these macros
+   incorrectly for preprocessor constants.  This workaround can likely
+   be removed in 2023, as HPE has promised support for HP-UX 11.23
+   (aka HP-UX 11i v2) only through the end of 2022; see Table 2 of
+   <https://h20195.www2.hpe.com/V2/getpdf.aspx/4AA4-7673ENW.pdf>.  */
+#ifdef __hpux
+# undef UINT_LEAST8_MAX
+# undef UINT_LEAST16_MAX
+# define UINT_LEAST8_MAX 255
+# define UINT_LEAST16_MAX 65535
+#endif
+
 #if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
 typedef __UINT_LEAST8_TYPE__ yytype_uint8;
 #elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \

From 1ac973aa568342700bfd404b41b6f0081d6a2a67 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Tue, 12 Jan 2021 06:28:13 +0100
Subject: [PATCH 02/26] c: adjust _Noreturn to pedantic clang

Reported by Joe Nelson <joe@begriffs.com>.
https://lists.gnu.org/r/help-bison/2021-01/msg00004.html
Fixed by Paul Eggert in gnulib.
https://lists.gnu.org/r/bug-gnulib/2021-01/msg00156.html

* data/skeletons/c.m4 (b4_attribute_define): Adjust _Noreturn to
pedantic clang.
---
 data/skeletons/c.m4 | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/data/skeletons/c.m4 b/data/skeletons/c.m4
index 14a16a9d..8c08b0a5 100644
--- a/data/skeletons/c.m4
+++ b/data/skeletons/c.m4
@@ -378,14 +378,16 @@ dnl use C' _Noreturn in C++, to avoid -Wc11-extensions warnings.
       && ((201103 <= __cplusplus && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \
           || (defined _MSC_VER && 1900 <= _MSC_VER)))
 #  define _Noreturn [[noreturn]]
-# elif (!defined __cplusplus                     \
-        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0)  \
-            || 4 < __GNUC__ + (7 <= __GNUC_MINOR__) \
-            || (defined __apple_build_version__ \
-                ? 6000000 <= __apple_build_version__ \
-                : 3 < __clang_major__ + (5 <= __clang_minor__))))
+# elif ((!defined __cplusplus || defined __clang__) \
+        && (201112 <= (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) \
+            || (!defined __STRICT_ANSI__ \
+                && (__4 < __GNUC__ + (7 <= __GNUC_MINOR__) \
+                    || (defined __apple_build_version__ \
+                        ? 6000000 <= __apple_build_version__ \
+                        : 3 < __clang_major__ + (5 <= __clang_minor__))))))
    /* _Noreturn works as-is.  */
-# elif 2 < __GNUC__ + (8 <= __GNUC_MINOR__) || 0x5110 <= __SUNPRO_C
+# elif (2 < __GNUC__ + (8 <= __GNUC_MINOR__) || defined __clang__ \
+        || 0x5110 <= __SUNPRO_C)
 #  define _Noreturn __attribute__ ((__noreturn__))
 # elif 1200 <= (defined _MSC_VER ? _MSC_VER : 0)
 #  define _Noreturn __declspec (noreturn)

From 4744faf2055d5b3aacfacc10ba8b4bb84693ec24 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 Jan 2021 15:37:19 +0100
Subject: [PATCH 03/26] autoconf: update

---
 submodules/autoconf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/submodules/autoconf b/submodules/autoconf
index babc8660..66fdaea3 160000
--- a/submodules/autoconf
+++ b/submodules/autoconf
@@ -1 +1 @@
-Subproject commit babc8660d5a7561ed7e99e09aeabffaccfe06d6d
+Subproject commit 66fdaea3cfb4e758212c1891913e9a59441d49af

From 1e0b0872448debb5e51c6393d11489a8d8166207 Mon Sep 17 00:00:00 2001
From: Martin Rehak <martin.rehak@oracle.com>
Date: Wed, 18 Nov 2020 09:10:01 +0100
Subject: [PATCH 04/26] examples: avoid "unbound variable" errors

When the shell option `nounset` is set, we may get "unbound variable"
errors.
https://lists.gnu.org/r/bug-bison/2020-11/msg00013.html

* examples/test (diff_opts): Be sure to initialize it.
---
 examples/test | 1 +
 1 file changed, 1 insertion(+)

diff --git a/examples/test b/examples/test
index 81076701..7590e128 100755
--- a/examples/test
+++ b/examples/test
@@ -37,6 +37,7 @@ strip_prompt=false
 # If diff supports --strip-trailing-cr, use it, to avoid EOL issues
 # when testing Java programs on Windows.
 echo "checking for diff --strip-trailing-cr..."
+diff_opts=
 if diff --strip-trailing-cr "$1" "$1"; then
   diff_opts=--strip-trailing-cr
 fi

From 89d2b69c1b926c9dc1da3834ba2a7a924d4e2d4f Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 2 Dec 2020 21:38:43 +0100
Subject: [PATCH 05/26] c++: use noexcept where appropriate

Reported by Don Macpherson.
https://github.com/akimd/bison/issues/63
https://github.com/akimd/bison/issues/64

* data/skeletons/c++.m4, data/skeletons/lalr1.cc: here.
---
 data/skeletons/c++.m4   | 6 +++---
 data/skeletons/lalr1.cc | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/data/skeletons/c++.m4 b/data/skeletons/c++.m4
index 78c66def..5081273f 100644
--- a/data/skeletons/c++.m4
+++ b/data/skeletons/c++.m4
@@ -340,7 +340,7 @@ m4_define([b4_symbol_type_define],
       }
 
       /// Destroy contents, and record that is empty.
-      void clear ()
+      void clear () YY_NOEXCEPT
       {]b4_variant_if([[
         // User destructor.
         symbol_kind_type yykind = this->kind ();
@@ -424,7 +424,7 @@ m4_define([b4_symbol_type_define],
       by_kind (kind_type t);
 
       /// Record that this symbol is empty.
-      void clear ();
+      void clear () YY_NOEXCEPT;
 
       /// Steal the symbol kind from \a that.
       void move (by_kind& that);
@@ -544,7 +544,7 @@ m4_define([b4_public_types_define],
   {}
 
   ]b4_inline([$1])[void
-  ]b4_parser_class[::by_kind::clear ()
+  ]b4_parser_class[::by_kind::clear () YY_NOEXCEPT
   {
     kind_ = ]b4_symbol(-2, kind)[;
   }
diff --git a/data/skeletons/lalr1.cc b/data/skeletons/lalr1.cc
index b95f9aa9..6214f96f 100644
--- a/data/skeletons/lalr1.cc
+++ b/data/skeletons/lalr1.cc
@@ -271,9 +271,9 @@ m4_define([b4_shared_declarations],
     {
     public:
       context (const ]b4_parser_class[& yyparser, const symbol_type& yyla);
-      const symbol_type& lookahead () const { return yyla_; }
-      symbol_kind_type token () const { return yyla_.kind (); }]b4_locations_if([[
-      const location_type& location () const { return yyla_.location; }
+      const symbol_type& lookahead () const YY_NOEXCEPT { return yyla_; }
+      symbol_kind_type token () const YY_NOEXCEPT { return yyla_.kind (); }]b4_locations_if([[
+      const location_type& location () const YY_NOEXCEPT { return yyla_.location; }
 ]])[
       /// Put in YYARG at most YYARGN of the expected tokens, and return the
       /// number of tokens stored in YYARG.  If YYARG is null, return the

From 1d3df34671ad4f0f60fef87558c6eb87b572eb14 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 2 Dec 2020 21:39:26 +0100
Subject: [PATCH 06/26] tables: avoid warnings and save bits

The yydefgoto table uses -1 as an invalid for an impossible case (we
never use yydefgoto[0], since it corresponds to the reduction to
$accept, which never happens).  Since yydefgoto is a table of state
numbers, this -1 forces a signed type uselessly, which (1) might
trigger compiler warnings when storing a value from yydefgoto into a
state number (nonnegative), and (2) wastes bits which might result in
using a int16 where a uint8 suffices.

Reported by Jot Dot <jotdot@shaw.ca>.
https://lists.gnu.org/r/bug-bison/2020-11/msg00027.html

* src/tables.c (default_goto): Use 0 rather than -1 as invalid value.
* tests/regression.at: Adjust.
---
 src/parse-gram.c    | 26 +++++++++++++++++++-------
 src/parse-gram.h    |  2 +-
 src/tables.c        |  9 ++++++++-
 tests/regression.at |  2 +-
 4 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/src/parse-gram.c b/src/parse-gram.c
index cfca03b5..3071f803 100644
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.3.7-d831b.  */
+/* A Bison parser, made by GNU Bison 3.7.4.6-89d2b-dirty.  */
 
 /* Bison implementation for Yacc-like parsers in C
 
@@ -45,11 +45,11 @@
    define necessary library symbols; they are noted "INFRINGES ON
    USER NAME SPACE" below.  */
 
-/* Identify Bison output.  */
-#define YYBISON 30703
+/* Identify Bison output, and Bison version.  */
+#define YYBISON 30704
 
-/* Bison version.  */
-#define YYBISON_VERSION "3.7.3.7-d831b"
+/* Bison version string.  */
+#define YYBISON_VERSION "3.7.4.6-89d2b-dirty"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -365,6 +365,18 @@ typedef int_least16_t yytype_int16;
 typedef short yytype_int16;
 #endif
 
+/* Work around bug in HP-UX 11.23, which defines these macros
+   incorrectly for preprocessor constants.  This workaround can likely
+   be removed in 2023, as HPE has promised support for HP-UX 11.23
+   (aka HP-UX 11i v2) only through the end of 2022; see Table 2 of
+   <https://h20195.www2.hpe.com/V2/getpdf.aspx/4AA4-7673ENW.pdf>.  */
+#ifdef __hpux
+# undef UINT_LEAST8_MAX
+# undef UINT_LEAST16_MAX
+# define UINT_LEAST8_MAX 255
+# define UINT_LEAST16_MAX 65535
+#endif
+
 #if defined __UINT_LEAST8_MAX__ && __UINT_LEAST8_MAX__ <= __INT_MAX__
 typedef __UINT_LEAST8_TYPE__ yytype_uint8;
 #elif (!defined __UINT_LEAST8_MAX__ && defined YY_STDINT_H \
@@ -791,9 +803,9 @@ static const yytype_int16 yypgoto[] =
 };
 
   /* YYDEFGOTO[NTERM-NUM].  */
-static const yytype_int16 yydefgoto[] =
+static const yytype_uint8 yydefgoto[] =
 {
-      -1,     1,     2,    43,    82,   115,    77,    45,    84,    46,
+       0,     1,     2,    43,    82,   115,    77,    45,    84,    46,
       50,    49,    47,   156,   120,   121,   122,    97,    93,    94,
       95,   128,   141,    87,    88,    89,    55,    56,    78,    79,
       80,   135,   144,   145,   113,    63,   106,    57,    81,    58,
diff --git a/src/parse-gram.h b/src/parse-gram.h
index ad4534ff..fcab0ce6 100644
--- a/src/parse-gram.h
+++ b/src/parse-gram.h
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.3.7-d831b.  */
+/* A Bison parser, made by GNU Bison 3.7.4.6-89d2b-dirty.  */
 
 /* Bison interface for Yacc-like parsers in C
 
diff --git a/src/tables.c b/src/tables.c
index 052e96e6..d26a4a97 100644
--- a/src/tables.c
+++ b/src/tables.c
@@ -512,7 +512,14 @@ default_goto (symbol_number sym, size_t state_count[])
 {
   const goto_number begin = goto_map[sym - ntokens];
   const goto_number end = goto_map[sym - ntokens + 1];
-  state_number res = -1;
+
+  /* In the case this symbol is never reduced to ($accept), use state
+     0.  We used to use -1, but as a result the yydefgoto table must
+     be signed, which (1) might trigger compiler warnings when storing
+     a value from yydefgoto into a state number (nonnegative), and (2)
+     wastes bits which might result in using a int16 where a uint8
+     suffices. */
+  state_number res = 0;
 
   if (begin != end)
     {
diff --git a/tests/regression.at b/tests/regression.at
index 099b39a0..20b5f739 100644
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -737,7 +737,7 @@ static const yytype_int8 yypgoto[] =
 };
 static const yytype_int8 yydefgoto[] =
 {
-      -1,     2,     3,     4,     8
+       0,     2,     3,     4,     8
 };
 static const yytype_int8 yytable[] =
 {

From a700a138228ed0d94bbfcf4feeb90093d2fbeca9 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 5 Dec 2020 06:49:48 +0100
Subject: [PATCH 07/26] glr.cc: don't "leak" yyparse

When using glr.cc, the C function yyparse is an internal detail that
should not be exposed.  Users might call it by accident (I did).

* data/skeletons/glr.c (yyparse): When used for glr.cc, rename as yy_parse_impl.
* data/skeletons/glr.cc: Adjust.
---
 data/skeletons/glr.c  | 4 ++--
 data/skeletons/glr.cc | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index a50f1804..1456b4ec 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -215,7 +215,7 @@ b4_copyright([Skeleton implementation for Bison GLR parsers in C],
 #define YYLTYPE ]b4_api_PREFIX[LTYPE]])])[
 ]m4_if(b4_prefix, [yy], [],
 [[/* Substitute the variable and function names.  */
-#define yyparse ]b4_prefix[parse
+#define ]b4_glr_cc_if([yy_parse_impl], [yyparse])[ ]b4_prefix[]b4_glr_cc_if([_parse_impl], [parse])[
 #define yylex   ]b4_prefix[lex
 #define yyerror ]b4_prefix[error
 #define yydebug ]b4_prefix[debug]]b4_pure_if([], [[
@@ -2420,7 +2420,7 @@ yyrecoverSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
 `----------*/
 
 int
-yyparse (]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param)], [void])[)
+]b4_glr_cc_if([yy_parse_impl], [yyparse])[ (]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param)], [void])[)
 {
   int yyresult;
   yyGLRStack yystack;
diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index 8ba34fc2..cf2c4c20 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -144,7 +144,7 @@ m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
   int
   ]b4_parser_class[::parse ()
   {
-    return ::yyparse (*this]b4_user_args[);
+    return ::yy_parse_impl (*this]b4_user_args[);
   }
 
 #if ]b4_api_PREFIX[DEBUG

From 3b03c62e49f2c94bc797a1a81ffb4c32fa7ea986 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sun, 3 Jan 2021 20:08:35 +0100
Subject: [PATCH 08/26] c++: I'm tired of Flex's warnings

* doc/bison.texi: Disable another warning I'm tired to see.
New releases would be most welcome.
---
 doc/bison.texi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/doc/bison.texi b/doc/bison.texi
index d38801db..4e9bb58b 100644
--- a/doc/bison.texi
+++ b/doc/bison.texi
@@ -13555,6 +13555,14 @@ then the parser's to get the set of defined tokens.
 #  pragma GCC diagnostic ignored "-Wsign-conversion"
 # endif
 #endif
+
+// Flex 2.6.4, GCC 9
+// warning: useless cast to type 'int' [-Wuseless-cast]
+// 1361 |   YY_CURRENT_BUFFER_LVALUE->yy_buf_size = (int) (new_size - 2);
+//      |                                                 ^
+#if defined GCC_VERSION && 900 <= GCC_VERSION
+# pragma GCC diagnostic ignored "-Wuseless-cast"
+#endif
 %@}
 @end example
 @end ignore

From 8320691a63ca3bccb21360f780db0e727b6e6567 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 13 Jan 2021 08:01:02 +0100
Subject: [PATCH 09/26] cex: send traces to stderr, not stdout

When comparing traces from different machines, the mixture of
stdout/stderr in the output are making things uselessly difficult.

* src/lssi.c, src/state-item.c: Output debug traces on stderr.
---
 src/lssi.c       | 13 +++++++------
 src/state-item.c | 34 ++++++++++++++++------------------
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/src/lssi.c b/src/lssi.c
index a5ab8a79..8c26ade0 100644
--- a/src/lssi.c
+++ b/src/lssi.c
@@ -102,15 +102,16 @@ append_lssi (lssi *sn, Hash_table *visited, lssi_list queue)
 static void
 lssi_print (lssi *l)
 {
-  print_state_item (&state_items[l->si], stdout);
+  FILE *out = stderr;
+  print_state_item (&state_items[l->si], out);
   if (l->lookahead)
     {
-      printf ("FOLLOWL = { ");
+      fprintf (out, "FOLLOWL = { ");
       bitset_iterator biter;
       symbol_number sin;
       BITSET_FOR_EACH (biter, l->lookahead, sin, 0)
-        printf ("%s, \n", symbols[sin]->tag);
-      puts ("}");
+        fprintf (out, "%s, \n", symbols[sin]->tag);
+      fprintf (out, "}");
     }
 }
 #endif
@@ -252,11 +253,11 @@ shortest_path_from_start (state_item_number target, symbol_number next_sym)
 
   if (trace_flag & trace_cex)
     {
-      puts ("REDUCE ITEM PATH:");
+      fputs ("REDUCE ITEM PATH:", stderr);
       gl_list_iterator_t it = gl_list_iterator (res);
       const void *sip;
       while (gl_list_iterator_next (&it, &sip, NULL))
-        state_item_print ((state_item *) sip, stdout, "");
+        state_item_print ((state_item *) sip, stderr, "");
     }
   return res;
 }
diff --git a/src/state-item.c b/src/state-item.c
index a0c5a31a..5080a4c8 100644
--- a/src/state-item.c
+++ b/src/state-item.c
@@ -486,27 +486,26 @@ state_item_print (const state_item *si, FILE *out, const char *prefix)
  * Report the state_item graph
  */
 static void
-state_items_report (void)
+state_items_report (FILE *out)
 {
-  printf ("# state items: %zu\n", nstate_items);
+  fprintf (out, "# state items: %zu\n", nstate_items);
   for (state_number i = 0; i < nstates; ++i)
     {
-      printf ("State %d:\n", i);
+      fprintf (out, "State %d:\n", i);
       for (state_item_number j = state_item_map[i]; j < state_item_map[i + 1]; ++j)
         {
           state_item *si = &state_items[j];
-          item_print (si->item, NULL, stdout);
+          item_print (si->item, NULL, out);
           if (SI_DISABLED (j))
             {
-              item_print (si->item, NULL, stdout);
-              puts (" DISABLED");
+              item_print (si->item, NULL, out);
+              fputs (" DISABLED", out);
               continue;
             }
-          puts ("");
           if (si->trans >= 0)
             {
-              fputs ("    -> ", stdout);
-              state_item_print (&state_items[si->trans], stdout, "");
+              fputs ("    -> ", out);
+              state_item_print (&state_items[si->trans], out, "");
             }
 
           bitset sets[2] = { si->prods, si->revs };
@@ -520,24 +519,23 @@ state_items_report (void)
                   state_item_number sin;
                   BITSET_FOR_EACH (biter, b, sin, 0)
                     {
-                      fputs (txt[seti], stdout);
-                      state_item_print (&state_items[sin], stdout, "");
+                      fputs (txt[seti], out);
+                      state_item_print (&state_items[sin], out, "");
                     }
                 }
             }
-          puts ("");
         }
     }
-  printf ("FIRSTS\n");
+  fprintf (out, "FIRSTS\n");
   for (symbol_number i = ntokens; i < nsyms; ++i)
     {
-      printf ("  %s firsts\n", symbols[i]->tag);
+      fprintf (out, "  %s firsts\n", symbols[i]->tag);
       bitset_iterator iter;
       symbol_number j;
       BITSET_FOR_EACH (iter, FIRSTS (i), j, 0)
-        printf ("    %s\n", symbols[j]->tag);
+        fprintf (out, "    %s\n", symbols[j]->tag);
     }
-  puts ("\n");
+  fputc ('\n', out);
 }
 
 void
@@ -552,8 +550,8 @@ state_items_init (void)
   prune_disabled_paths ();
   if (trace_flag & trace_cex)
     {
-      printf ("init: %f\n", difftime (time (NULL), start));
-      state_items_report ();
+      fprintf (stderr, "init: %f\n", difftime (time (NULL), start));
+      state_items_report (stderr);
     }
 }
 

From 7a31b6bb7f24d925851be1849dbf1dbbd3b69826 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Thu, 14 Jan 2021 06:32:39 +0100
Subject: [PATCH 10/26] cex: add support for $TIME_LIMIT

* src/counterexample.c (TIME_LIMIT): Replace with...
(time_limit): this.
(counterexample_init): Check $TIME_LIMIT.
* src/scan-gram.l: Reorder includes.
---
 src/counterexample.c | 18 ++++++++++++++++--
 src/scan-gram.l      |  3 +--
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/counterexample.c b/src/counterexample.c
index 8a19aa51..b4caef7d 100644
--- a/src/counterexample.c
+++ b/src/counterexample.c
@@ -23,6 +23,7 @@
 
 #include "system.h"
 
+#include <errno.h>
 #include <gl_linked_list.h>
 #include <gl_rbtreehash_list.h>
 #include <hash.h>
@@ -59,7 +60,7 @@
 #define ASSURANCE_LIMIT 2.0f
 
 /* The time limit before giving up looking for unifying counterexample. */
-#define TIME_LIMIT 5.0f
+static float time_limit = 5.0f;
 
 #define CUMULATIVE_TIME_LIMIT 120.0f
 
@@ -1171,7 +1172,7 @@ unifying_example (state_item_number itm1,
                          stderr);
                   assurance_printed = true;
                 }
-              if (time_passed > TIME_LIMIT)
+              if (time_passed > time_limit)
                 {
                   fprintf (stderr, "time limit exceeded: %f\n", time_passed);
                   goto cex_search_end;
@@ -1208,6 +1209,19 @@ static time_t cumulative_time;
 void
 counterexample_init (void)
 {
+  /* Recognize $TIME_LIMIT.  Not a public feature, just to help
+     debugging.  If we need something public, a %define/-D/-F variable
+     would be more appropriate. */
+  {
+    const char *cp = getenv ("TIME_LIMIT");
+    if (cp)
+      {
+        char *end = NULL;
+        float v = strtof (cp, &end);
+        if (*end == '\0' && errno == 0)
+          time_limit = v;
+      }
+    }
   time (&cumulative_time);
   scp_set = bitset_create (nstates, BITSET_FIXED);
   rpp_set = bitset_create (nstates, BITSET_FIXED);
diff --git a/src/scan-gram.l b/src/scan-gram.l
index e10d68e2..6d33cdf2 100644
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -21,9 +21,8 @@
 %option prefix="gram_" outfile="lex.yy.c"
 
 %{
-#include <errno.h>
-
 #include <c-ctype.h>
+#include <errno.h>
 #include <mbswidth.h>
 #include <quote.h>
 #include <quotearg.h>

From 2f554e62604ff9e5944f5d56842132c74697b70c Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 Jan 2021 14:37:05 +0100
Subject: [PATCH 11/26] cex: fix traces: add missing end-of-lines

In 430ca0fc632f5e8072fe468b8a99c640985f6926, I completely forgot that
`puts` adds a `\n`.

* src/lssi.c, src/state-item.c: Restore missing end-of-lines in the
output.
---
 src/lssi.c       | 4 ++--
 src/state-item.c | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/lssi.c b/src/lssi.c
index 8c26ade0..44dd819b 100644
--- a/src/lssi.c
+++ b/src/lssi.c
@@ -111,7 +111,7 @@ lssi_print (lssi *l)
       symbol_number sin;
       BITSET_FOR_EACH (biter, l->lookahead, sin, 0)
         fprintf (out, "%s, \n", symbols[sin]->tag);
-      fprintf (out, "}");
+      fprintf (out, "}\n");
     }
 }
 #endif
@@ -253,7 +253,7 @@ shortest_path_from_start (state_item_number target, symbol_number next_sym)
 
   if (trace_flag & trace_cex)
     {
-      fputs ("REDUCE ITEM PATH:", stderr);
+      fputs ("REDUCE ITEM PATH:\n", stderr);
       gl_list_iterator_t it = gl_list_iterator (res);
       const void *sip;
       while (gl_list_iterator_next (&it, &sip, NULL))
diff --git a/src/state-item.c b/src/state-item.c
index 5080a4c8..5ca9795a 100644
--- a/src/state-item.c
+++ b/src/state-item.c
@@ -499,9 +499,10 @@ state_items_report (FILE *out)
           if (SI_DISABLED (j))
             {
               item_print (si->item, NULL, out);
-              fputs (" DISABLED", out);
+              fputs (" DISABLED\n", out);
               continue;
             }
+          putc ('\n', out);
           if (si->trans >= 0)
             {
               fputs ("    -> ", out);
@@ -524,6 +525,7 @@ state_items_report (FILE *out)
                     }
                 }
             }
+          putc ('\n', out);
         }
     }
   fprintf (out, "FIRSTS\n");
@@ -535,7 +537,7 @@ state_items_report (FILE *out)
       BITSET_FOR_EACH (iter, FIRSTS (i), j, 0)
         fprintf (out, "    %s\n", symbols[j]->tag);
     }
-  fputc ('\n', out);
+  fputs ("\n\n", out);
 }
 
 void

From 83bc8895367bf27f8ae78fea9ade8a8d94786698 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 Jan 2021 15:05:30 +0100
Subject: [PATCH 12/26] cex: fix traces: fix display of disabled items
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The display of disabled state items is incorrect.  The item is
stuttered, and lacks on end-of-line.

From

    State 7:
        1 exp: exp • "⊕" exp
        ->     1 exp: exp "⊕" • exp
        <-     1 exp: • exp "⊕" exp

        2 exp: exp • "+" exp    2 exp: exp • "+" exp DISABLED
        2 exp: exp "+" exp •
        <-     2 exp: exp "+" • exp

        3 exp: exp • "+" exp    3 exp: exp • "+" exp DISABLED
        3 exp: exp "+" exp •
        <-     3 exp: exp "+" • exp

to

    State 7:
        1 exp: exp • "⊕" exp
        ->     1 exp: exp "⊕" • exp
        <-     1 exp: • exp "⊕" exp

        2 exp: exp • "+" exp  DISABLED

        2 exp: exp "+" exp •
        <-     2 exp: exp "+" • exp

        3 exp: exp • "+" exp  DISABLED

        3 exp: exp "+" exp •
        <-     3 exp: exp "+" • exp

* src/state-item.c (state_items_report): Don't issue disabled items
twice, and issue two '\n' at their end.
* tests/conflicts.at: Check it.
---
 src/state-item.c   |  45 ++++----
 tests/conflicts.at | 280 ++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 301 insertions(+), 24 deletions(-)

diff --git a/src/state-item.c b/src/state-item.c
index 5ca9795a..05cb8075 100644
--- a/src/state-item.c
+++ b/src/state-item.c
@@ -494,34 +494,33 @@ state_items_report (FILE *out)
       fprintf (out, "State %d:\n", i);
       for (state_item_number j = state_item_map[i]; j < state_item_map[i + 1]; ++j)
         {
-          state_item *si = &state_items[j];
+          const state_item *si = &state_items[j];
           item_print (si->item, NULL, out);
           if (SI_DISABLED (j))
+            fputs ("  DISABLED\n", out);
+          else
             {
-              item_print (si->item, NULL, out);
-              fputs (" DISABLED\n", out);
-              continue;
-            }
-          putc ('\n', out);
-          if (si->trans >= 0)
-            {
-              fputs ("    -> ", out);
-              state_item_print (&state_items[si->trans], out, "");
-            }
-
-          bitset sets[2] = { si->prods, si->revs };
-          const char *txt[2] = { "    => ", "    <- " };
-          for (int seti = 0; seti < 2; ++seti)
-            {
-              bitset b = sets[seti];
-              if (b)
+              putc ('\n', out);
+              if (si->trans >= 0)
                 {
-                  bitset_iterator biter;
-                  state_item_number sin;
-                  BITSET_FOR_EACH (biter, b, sin, 0)
+                  fputs ("    -> ", out);
+                  state_item_print (&state_items[si->trans], out, "");
+                }
+
+              bitset sets[2] = { si->prods, si->revs };
+              const char *txt[2] = { "    => ", "    <- " };
+              for (int seti = 0; seti < 2; ++seti)
+                {
+                  bitset b = sets[seti];
+                  if (b)
                     {
-                      fputs (txt[seti], out);
-                      state_item_print (&state_items[sin], out, "");
+                      bitset_iterator biter;
+                      state_item_number sin;
+                      BITSET_FOR_EACH (biter, b, sin, 0)
+                        {
+                          fputs (txt[seti], out);
+                          state_item_print (&state_items[sin], out, "");
+                        }
                     }
                 }
             }
diff --git a/tests/conflicts.at b/tests/conflicts.at
index 2b6f4315..befd017b 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -1956,7 +1956,285 @@ empty_c2: %prec 'c' ;
 empty_c3: %prec 'c' ;
 ]])
 
-AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
+AT_BISON_CHECK([[--trace=cex -fcaret --report=all -o input.c input.y]], 0, [],
+[[init: 0.000000
+# state items: 26
+State 0:
+    0 $accept: . start $end
+    ->     0 $accept: start . $end
+    =>     2 start: . empty_a 'a'
+    =>     4 start: . empty_b 'b'
+    =>     6 start: . empty_c1 'c'
+    =>     7 start: . empty_c2 'c'
+    =>     8 start: . empty_c3 'c'
+
+    1 start: . 'a'  DISABLED
+
+    2 start: . empty_a 'a'
+    ->     2 start: empty_a . 'a'
+    =>     9 empty_a: . %empty
+    <-     0 $accept: . start $end
+
+    3 start: . 'b'  DISABLED
+
+    4 start: . empty_b 'b'
+    ->     4 start: empty_b . 'b'
+    =>    10 empty_b: . %empty
+    <-     0 $accept: . start $end
+
+    5 start: . 'c'  DISABLED
+
+    6 start: . empty_c1 'c'
+    ->     6 start: empty_c1 . 'c'
+    =>    11 empty_c1: . %empty
+    <-     0 $accept: . start $end
+
+    7 start: . empty_c2 'c'
+    ->     7 start: empty_c2 . 'c'
+    =>    12 empty_c2: . %empty
+    <-     0 $accept: . start $end
+
+    8 start: . empty_c3 'c'
+    ->     8 start: empty_c3 . 'c'
+    =>    13 empty_c3: . %empty
+    <-     0 $accept: . start $end
+
+    9 empty_a: . %empty
+    <-     2 start: . empty_a 'a'
+
+   10 empty_b: . %empty
+    <-     4 start: . empty_b 'b'
+
+   11 empty_c1: . %empty
+    <-     6 start: . empty_c1 'c'
+
+   12 empty_c2: . %empty
+    <-     7 start: . empty_c2 'c'
+
+   13 empty_c3: . %empty
+    <-     8 start: . empty_c3 'c'
+
+State 1:
+    0 $accept: start . $end
+    ->     0 $accept: start $end .
+    <-     0 $accept: . start $end
+
+State 2:
+    2 start: empty_a . 'a'
+    ->     2 start: empty_a 'a' .
+    <-     2 start: . empty_a 'a'
+
+State 3:
+    4 start: empty_b . 'b'
+    ->     4 start: empty_b 'b' .
+    <-     4 start: . empty_b 'b'
+
+State 4:
+    6 start: empty_c1 . 'c'
+    ->     6 start: empty_c1 'c' .
+    <-     6 start: . empty_c1 'c'
+
+State 5:
+    7 start: empty_c2 . 'c'
+    ->     7 start: empty_c2 'c' .
+    <-     7 start: . empty_c2 'c'
+
+State 6:
+    8 start: empty_c3 . 'c'
+    ->     8 start: empty_c3 'c' .
+    <-     8 start: . empty_c3 'c'
+
+State 7:
+    0 $accept: start $end .
+    <-     0 $accept: start . $end
+
+State 8:
+    2 start: empty_a 'a' .
+    <-     2 start: empty_a . 'a'
+
+State 9:
+    4 start: empty_b 'b' .
+    <-     4 start: empty_b . 'b'
+
+State 10:
+    6 start: empty_c1 'c' .
+    <-     6 start: empty_c1 . 'c'
+
+State 11:
+    7 start: empty_c2 'c' .
+    <-     7 start: empty_c2 . 'c'
+
+State 12:
+    8 start: empty_c3 'c' .
+    <-     8 start: empty_c3 . 'c'
+
+FIRSTS
+  $accept firsts
+    'a'
+    'b'
+    'c'
+  start firsts
+    'a'
+    'b'
+    'c'
+  empty_a firsts
+  empty_b firsts
+  empty_c1 firsts
+  empty_c2 firsts
+  empty_c3 firsts
+
+
+input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
+input.y:4.5-7: warning: rule useless in parser due to conflicts [-Wother]
+    4 |     'a'
+      |     ^~~
+input.y:6.5-7: warning: rule useless in parser due to conflicts [-Wother]
+    6 |   | 'b'
+      |     ^~~
+input.y:8.5-7: warning: rule useless in parser due to conflicts [-Wother]
+    8 |   | 'c'
+      |     ^~~
+input.y:13.10-18: warning: rule useless in parser due to conflicts [-Wother]
+   13 | empty_a: %prec 'a' ;
+      |          ^~~~~~~~~
+input.y:14.10-18: warning: rule useless in parser due to conflicts [-Wother]
+   14 | empty_b: %prec 'b' ;
+      |          ^~~~~~~~~
+input.y:15.11-19: warning: rule useless in parser due to conflicts [-Wother]
+   15 | empty_c1: %prec 'c' ;
+      |           ^~~~~~~~~
+input.y:16.11-19: warning: rule useless in parser due to conflicts [-Wother]
+   16 | empty_c2: %prec 'c' ;
+      |           ^~~~~~~~~
+input.y:17.11-19: warning: rule useless in parser due to conflicts [-Wother]
+   17 | empty_c3: %prec 'c' ;
+      |           ^~~~~~~~~
+REDUCE ITEM PATH:
+    0 $accept: . start $end
+    7 start: . empty_c2 'c'
+   12 empty_c2: . %empty
+CONFLICT 1 (size 1 depth 0 rc 2)
+   12 empty_c2: . %empty
+   12 empty_c2: . %empty
+
+    .
+
+CONFLICT 2 (size 1 depth 0 rc 2)
+   13 empty_c3: . %empty
+   13 empty_c3: . %empty
+
+    .
+
+
+CONFLICT 1 (size 2 depth -1 rc 4)
+    7 start: . empty_c2 'c'
+    7 start: empty_c2 . 'c'
+
+    empty_c2
+    `-> .
+
+CONFLICT 2 (size 1 depth 0 rc 3)
+   13 empty_c3: . %empty
+   13 empty_c3: . %empty
+
+    .
+
+
+CONFLICT 1 (size 1 depth 0 rc 3)
+   12 empty_c2: . %empty
+   12 empty_c2: . %empty
+
+    .
+
+CONFLICT 2 (size 2 depth -1 rc 2)
+    8 start: . empty_c3 'c'
+    8 start: empty_c3 . 'c'
+
+    empty_c3
+    `-> .
+
+
+CONFLICT 1 (size 2 depth -1 rc 3)
+    7 start: . empty_c2 'c'
+    7 start: empty_c2 . 'c'
+
+    empty_c2
+    `-> .
+
+CONFLICT 2 (size 2 depth -1 rc 2)
+    8 start: . empty_c3 'c'
+    8 start: empty_c3 . 'c'
+
+    empty_c3
+    `-> .
+
+
+CONFLICT 1 (size 3 depth -1 rc 2)
+    7 start: . empty_c2 'c'
+    7 start: empty_c2 'c' .
+
+    empty_c2
+    `-> .
+
+CONFLICT 2 (size 3 depth -1 rc 2)
+    8 start: . empty_c3 'c'
+    8 start: empty_c3 'c' .
+
+    empty_c3
+    `-> .
+
+
+CONFLICT 1 (size 2 depth -1 rc 4)
+    0 $accept: . start $end
+    0 $accept: start . $end
+
+    start
+    `-> empty_c2 'c'
+        `-> .
+
+CONFLICT 2 (size 3 depth -1 rc 3)
+    8 start: . empty_c3 'c'
+    8 start: empty_c3 'c' .
+
+    empty_c3
+    `-> .
+
+
+CONFLICT 1 (size 3 depth -1 rc 3)
+    7 start: . empty_c2 'c'
+    7 start: empty_c2 'c' .
+
+    empty_c2
+    `-> .
+
+CONFLICT 2 (size 2 depth -1 rc 2)
+    0 $accept: . start $end
+    0 $accept: start . $end
+
+    start
+    `-> empty_c3 'c'
+        `-> .
+
+
+CONFLICT 1 (size 2 depth -1 rc 3)
+    0 $accept: . start $end
+    0 $accept: start . $end
+
+    start
+    `-> empty_c2 'c'
+        `-> .
+
+CONFLICT 2 (size 2 depth -1 rc 2)
+    0 $accept: . start $end
+    0 $accept: start . $end
+
+    start
+    `-> empty_c3 'c'
+        `-> .
+
+
+]])
 AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
 [[State 0
 

From 4910c025796684bf2a70341dde766cd68f3c6b2b Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 Jan 2021 18:05:57 +0100
Subject: [PATCH 13/26] package: codespell

* src/parse-gram.y: Fix spelling.
---
 Makefile.am      | 3 ++-
 src/parse-gram.y | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 7db4fe11..f94842c4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -133,9 +133,10 @@ gen-ChangeLog:
 	$(CC) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -o $@ -E $<
 
 .PHONY: codespell
+CODESPELL = codespell
 codespell:
 	$(AM_V_GEN) cd $(srcdir) \
-	&& codespell \
+	&& $(CODESPELL) \
 	     --regex "[\\w\\-'’\`]+\+*" \
 	     --ignore-words-list "ba,circularly,cloneable,copyable,define'd,dout,froms,iff,ifset,od,ois" \
 	     $$(git ls-files data doc lib src tests)
diff --git a/src/parse-gram.y b/src/parse-gram.y
index 7c146ea3..2b24ac17 100644
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -513,7 +513,7 @@ tag:
 // A non empty list of possibly tagged symbols for %nterm.
 //
 // Can easily be defined like symbol_decls but restricted to ID, but
-// using token_decls allows to reudce the number of rules, and also to
+// using token_decls allows to reduce the number of rules, and also to
 // make nicer error messages on "%nterm 'a'" or '%nterm FOO "foo"'.
 nterm_decls:
   token_decls

From 11f6839645fcac9d4ac3470f19e385d312e10b8d Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 23 Jan 2021 09:42:24 +0100
Subject: [PATCH 14/26] style: YYUSE is private, make it YY_USE

This macro is not exposed to users, make start it with 'YY_'.

* data/skeletons/bison.m4, data/skeletons/c.m4, data/skeletons/glr.c,
* data/skeletons/glr.cc, data/skeletons/lalr1.cc,
* src/parse-gram.c, tests/actions.at, tests/c++.at, tests/headers.at,
* tests/local.at (YYUSE): Rename as...
(YY_USE): this.
---
 data/skeletons/bison.m4 |  2 +-
 data/skeletons/c.m4     | 12 ++++++------
 data/skeletons/glr.c    | 14 +++++++-------
 data/skeletons/glr.cc   |  6 +++---
 data/skeletons/lalr1.cc |  4 ++--
 src/parse-gram.c        | 16 ++++++++--------
 src/parse-gram.h        |  2 +-
 tests/actions.at        |  8 ++++----
 tests/c++.at            |  6 +++---
 tests/headers.at        |  2 +-
 tests/local.at          |  6 +++---
 11 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/data/skeletons/bison.m4 b/data/skeletons/bison.m4
index 7ab1cb91..12155123 100644
--- a/data/skeletons/bison.m4
+++ b/data/skeletons/bison.m4
@@ -537,7 +537,7 @@ m4_defn([b4_actions_])[]dnl
         break;
     }dnl
 ],
-[YYUSE (m4_default([$2], [yykind]));])dnl
+[YY_USE (m4_default([$2], [yykind]));])dnl
 m4_popdef([b4_actions_])dnl
 ])
 
diff --git a/data/skeletons/c.m4 b/data/skeletons/c.m4
index 8c08b0a5..8a5c851b 100644
--- a/data/skeletons/c.m4
+++ b/data/skeletons/c.m4
@@ -160,11 +160,11 @@ m4_popdef([$1])dnl
 
 # b4_parse_param_use([VAL], [LOC])
 # --------------------------------
-# 'YYUSE' VAL, LOC if locations are enabled, and all the parse-params.
+# 'YY_USE' VAL, LOC if locations are enabled, and all the parse-params.
 m4_define([b4_parse_param_use],
-[m4_ifvaln([$1], [  YYUSE ([$1]);])dnl
-b4_locations_if([m4_ifvaln([$2], [  YYUSE ([$2]);])])dnl
-b4_parse_param_for([Decl], [Formal], [  YYUSE (Formal);
+[m4_ifvaln([$1], [  YY_USE ([$1]);])dnl
+b4_locations_if([m4_ifvaln([$2], [  YY_USE ([$2]);])])dnl
+b4_parse_param_for([Decl], [Formal], [  YY_USE (Formal);
 ])dnl
 ])
 
@@ -398,9 +398,9 @@ dnl use C' _Noreturn in C++, to avoid -Wc11-extensions warnings.
 
 ]])[/* Suppress unused-variable warnings by "using" E.  */
 #if ! defined lint || defined __GNUC__
-# define YYUSE(E) ((void) (E))
+# define YY_USE(E) ((void) (E))
 #else
-# define YYUSE(E) /* empty */
+# define YY_USE(E) /* empty */
 #endif
 
 #if defined __GNUC__ && ! defined __ICC && 407 <= __GNUC__ * 100 + __GNUC_MINOR__
diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index 1456b4ec..5034b5ef 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -875,7 +875,7 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
   yybool yynormal YY_ATTRIBUTE_UNUSED = yystackp->yysplitPoint == YY_NULLPTR;
   int yylow;
 ]b4_parse_param_use([yyvalp], [yylocp])dnl
-[  YYUSE (yyrhslen);
+[  YY_USE (yyrhslen);
 # undef yyerrok
 # define yyerrok (yystackp->yyerrState = 0)
 # undef YYACCEPT
@@ -939,8 +939,8 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
 static void
 yyuserMerge (int yyn, YYSTYPE* yy0, YYSTYPE* yy1)
 {
-  YYUSE (yy0);
-  YYUSE (yy1);
+  YY_USE (yy0);
+  YY_USE (yy1);
 
   switch (yyn)
     {
@@ -1795,8 +1795,8 @@ static YYRESULTTAG
 yyreportAmbiguity (yySemanticOption* yyx0,
                    yySemanticOption* yyx1]b4_pure_formals[)
 {
-  YYUSE (yyx0);
-  YYUSE (yyx1);
+  YY_USE (yyx0);
+  YY_USE (yyx1);
 
 #if ]b4_api_PREFIX[DEBUG
   YY_FPRINTF ((stderr, "Ambiguity detected.\n"));
@@ -2140,7 +2140,7 @@ yypcontext_token (const yyGLRStack *yystackp) YY_ATTRIBUTE_UNUSED;
 static yysymbol_kind_t
 yypcontext_token (const yyGLRStack *yystackp)
 {
-  YYUSE (yystackp);
+  YY_USE (yystackp);
   yysymbol_kind_t yytoken = yychar == ]b4_symbol(-2, id)[ ? ]b4_symbol(-2, kind)[ : YYTRANSLATE (yychar);
   return yytoken;
 }
@@ -2152,7 +2152,7 @@ yypcontext_location (const yyGLRStack *yystackp) YY_ATTRIBUTE_UNUSED;
 static YYLTYPE *
 yypcontext_location (const yyGLRStack *yystackp)
 {
-  YYUSE (yystackp);
+  YY_USE (yystackp);
   return &yylloc;
 }]])],
          [detailed\|verbose],
diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index cf2c4c20..cfff9773 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -157,11 +157,11 @@ m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
                            const semantic_type* yyvaluep]b4_locations_if([[,
                            const location_type* yylocationp]])[) const
   {]b4_locations_if([[
-    YYUSE (yylocationp);]])[
-    YYUSE (yyvaluep);
+    YY_USE (yylocationp);]])[
+    YY_USE (yyvaluep);
     std::ostream& yyo = debug_stream ();
     std::ostream& yyoutput = yyo;
-    YYUSE (yyoutput);
+    YY_USE (yyoutput);
     ]b4_symbol_actions([printer])[
   }
 
diff --git a/data/skeletons/lalr1.cc b/data/skeletons/lalr1.cc
index 6214f96f..c62c77d2 100644
--- a/data/skeletons/lalr1.cc
+++ b/data/skeletons/lalr1.cc
@@ -597,7 +597,7 @@ m4_if(b4_prefix, [yy], [],
 #else // !]b4_api_PREFIX[DEBUG
 
 # define YYCDEBUG if (false) std::cerr
-# define YY_SYMBOL_PRINT(Title, Symbol)  YYUSE (Symbol)
+# define YY_SYMBOL_PRINT(Title, Symbol)  YY_USE (Symbol)
 # define YY_REDUCE_PRINT(Rule)           static_cast<void> (0)
 # define YY_STACK_PRINT()                static_cast<void> (0)
 
@@ -736,7 +736,7 @@ m4_if(b4_prefix, [yy], [],
   ]b4_parser_class[::yy_print_ (std::ostream& yyo, const basic_symbol<Base>& yysym) const
   {
     std::ostream& yyoutput = yyo;
-    YYUSE (yyoutput);
+    YY_USE (yyoutput);
     if (yysym.empty ())
       yyo << "empty symbol";
     else
diff --git a/src/parse-gram.c b/src/parse-gram.c
index 3071f803..5b1ac0a6 100644
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.4.6-89d2b-dirty.  */
+/* A Bison parser, made by GNU Bison 3.7.4.23-44a69.  */
 
 /* Bison implementation for Yacc-like parsers in C
 
@@ -49,7 +49,7 @@
 #define YYBISON 30704
 
 /* Bison version string.  */
-#define YYBISON_VERSION "3.7.4.6-89d2b-dirty"
+#define YYBISON_VERSION "3.7.4.23-44a69"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -478,9 +478,9 @@ typedef int yy_state_fast_t;
 
 /* Suppress unused-variable warnings by "using" E.  */
 #if ! defined lint || defined __GNUC__
-# define YYUSE(E) ((void) (E))
+# define YY_USE(E) ((void) (E))
 #else
-# define YYUSE(E) /* empty */
+# define YY_USE(E) /* empty */
 #endif
 
 #if defined __GNUC__ && ! defined __ICC && 407 <= __GNUC__ * 100 + __GNUC_MINOR__
@@ -1072,8 +1072,8 @@ yy_symbol_value_print (FILE *yyo,
                        yysymbol_kind_t yykind, YYSTYPE const * const yyvaluep, YYLTYPE const * const yylocationp)
 {
   FILE *yyoutput = yyo;
-  YYUSE (yyoutput);
-  YYUSE (yylocationp);
+  YY_USE (yyoutput);
+  YY_USE (yylocationp);
   if (!yyvaluep)
     return;
 # ifdef YYPRINT
@@ -1701,8 +1701,8 @@ static void
 yydestruct (const char *yymsg,
             yysymbol_kind_t yykind, YYSTYPE *yyvaluep, YYLTYPE *yylocationp)
 {
-  YYUSE (yyvaluep);
-  YYUSE (yylocationp);
+  YY_USE (yyvaluep);
+  YY_USE (yylocationp);
   if (!yymsg)
     yymsg = "Deleting";
   YY_SYMBOL_PRINT (yymsg, yykind, yyvaluep, yylocationp);
diff --git a/src/parse-gram.h b/src/parse-gram.h
index fcab0ce6..7dbd0ffd 100644
--- a/src/parse-gram.h
+++ b/src/parse-gram.h
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.7.4.6-89d2b-dirty.  */
+/* A Bison parser, made by GNU Bison 3.7.4.23-44a69.  */
 
 /* Bison interface for Yacc-like parsers in C
 
diff --git a/tests/actions.at b/tests/actions.at
index d90851de..da11ceb2 100644
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -334,10 +334,10 @@ exp: { ]AT_CXX_IF([[std::cerr << @$ << '\n']],
 
 ]AT_YYLEX_PROTOTYPE[
 {]AT_PURE_IF([
-  YYUSE(lvalp);
-  YYUSE(llocp);], [AT_CXX_IF([
-  YYUSE(lvalp);
-  YYUSE(llocp);])])[
+  YY_USE(lvalp);
+  YY_USE(llocp);], [AT_CXX_IF([
+  YY_USE(lvalp);
+  YY_USE(llocp);])])[
   return 'x';
 }
 
diff --git a/tests/c++.at b/tests/c++.at
index 949bdeb6..b894c0f7 100644
--- a/tests/c++.at
+++ b/tests/c++.at
@@ -1232,10 +1232,10 @@ list:
 
 item:
   'a'     { $$ = $][1; }
-| 'e'     { YYUSE ($$); YYUSE ($][1); error ("syntax error"); }
+| 'e'     { YY_USE ($$); YY_USE ($][1); error ("syntax error"); }
 // Not just 'E', otherwise we reduce when 'E' is the lookahead, and
 // then the stack is emptied, defeating the point of the test.
-| 'E' 'a' { YYUSE ($][1); $$ = $][2; }
+| 'E' 'a' { YY_USE ($][1); $$ = $][2; }
 | 'R'     { ]AT_VARIANT_IF([], [$$ = YY_NULLPTR; delete $][1]; )[YYERROR; }
 | 'p'     { $$ = $][1; }
 | 's'     { $$ = $][1; throw std::runtime_error ("reduction"); }
@@ -1394,7 +1394,7 @@ int yylex (yy::parser::semantic_type *lvalp)
   // Note: this argument is unused, but named on purpose.  There used to be a
   // bug with a macro that erroneously expanded this identifier to
   // yystackp->yyval.
-  YYUSE (lvalp);
+  YY_USE (lvalp);
   return yy::parser::token::ZERO;
 }
 
diff --git a/tests/headers.at b/tests/headers.at
index 73a43454..4e745ccb 100644
--- a/tests/headers.at
+++ b/tests/headers.at
@@ -340,7 +340,7 @@ AT_PERL_CHECK([[-n -0777 -e '
       |YYNTOKENS  # This is actual scoped in a C++ class.
       |YYPUSH_MORE(?:_DEFINED)?
       |S_(YY(ACCEPT|EMPTY|EOF|error|UNDEF))  # These guys are scoped.
-      |YYUSE
+      |YY_USE
       |YY_ATTRIBUTE(?:_PURE|_UNUSED)
       |YY(?:_REINTERPRET)?_CAST
       |YY_CONSTEXPR
diff --git a/tests/local.at b/tests/local.at
index 91e1e734..c697f5a7 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -643,7 +643,7 @@ yyreport_syntax_error (const yypcontext_t *ctx]AT_PARAM_IF([, AT_PARSE_PARAMS])[
 {
   int res = 0;]AT_PARAM_IF([m4_bpatsubst(m4_defn([AT_PARSE_PARAMS]),
               [[^,]+[^A-Za-z_0-9]\([A-Za-z_][A-Za-z_0-9]*\),* *], [
-  YYUSE (\1);])])[]m4_bmatch(m4_defn([AT_PARSE_PARAMS]), [nerrs],[[
+  YY_USE (\1);])])[]m4_bmatch(m4_defn([AT_PARSE_PARAMS]), [nerrs],[[
   ++global_nerrs;
   ++*nerrs;]])[]AT_LOCATION_IF([[
   LOCATION_PRINT (stderr, *yypcontext_location (ctx));
@@ -679,7 +679,7 @@ static
 ]AT_YYERROR_PROTOTYPE[
 {]m4_bpatsubst(m4_defn([AT_PARSE_PARAMS]),
               [[^,]+[^A-Za-z_0-9]\([A-Za-z_][A-Za-z_0-9]*\),* *], [
-  YYUSE (\1);])dnl
+  YY_USE (\1);])dnl
 AT_YYERROR_SEES_LOC_IF([[
   LOCATION_PRINT (stderr, ]AT_LOC[);
   fprintf (stderr, ": ");]])[
@@ -760,7 +760,7 @@ void
 ]AT_NAMESPACE[::parser::report_syntax_error (const context& ctx) const
 {]AT_PARAM_IF([m4_bpatsubst(m4_defn([AT_PARSE_PARAMS]),
               [[^,]+[^A-Za-z_0-9]\([A-Za-z_][A-Za-z_0-9]*\),* *], [
-  YYUSE (\1);])])[]m4_bmatch(m4_defn([AT_PARSE_PARAMS]), [nerrs],[[
+  YY_USE (\1);])])[]m4_bmatch(m4_defn([AT_PARSE_PARAMS]), [nerrs],[[
   ++global_nerrs;
   ++*nerrs;]])[]AT_LOCATION_IF([[
   std::cerr << ctx.location () << ": ";]])[

From c73dcd6958ed73daff240ca46cc8b0f774a28e22 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 23 Jan 2021 10:14:19 +0100
Subject: [PATCH 15/26] skeletons: introduce "slot"s for symbols

Extracted from d9cf99b6a5cb0345e91dfb90fe6d6473024ea97a, in the master
branch.

* data/skeletons/bison.m4 (b4_symbol_slot): New, with safer semantics
than type and type_tag.
---
 data/README.md          |  8 +++++++-
 data/skeletons/bison.m4 | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/data/README.md b/data/README.md
index 50fbe525..59b220b0 100644
--- a/data/README.md
+++ b/data/README.md
@@ -142,11 +142,17 @@ The macro `b4_symbol(NUM, FIELD)` gives access to the following FIELDS:
   When api.value.type=union, the generated name for the union member.
   yytype_INT etc. for symbols that has_id, otherwise yytype_1 etc.
 
-- `type`
+- `type`: string
   If it has a semantic value, its type tag, or, if variant are used,
   its type.
   In the case of api.value.type=union, type is the real type (e.g. int).
 
+- `slot`: string
+  If it has a semantic value, the name of the union member (i.e., bounces to
+  either `type_tag` or `type`).  It would be better to fix our mess and
+  always use `type` for the true type of the member, and `type_tag` for the
+  name of the union member.
+
 - `has_printer`: 0, 1
 - `printer`: string
 - `printer_file`: string
diff --git a/data/skeletons/bison.m4 b/data/skeletons/bison.m4
index 12155123..156b0689 100644
--- a/data/skeletons/bison.m4
+++ b/data/skeletons/bison.m4
@@ -465,6 +465,19 @@ m4_case([$1],
 # but are S_YYEMPTY and symbol_kind::S_YYEMPTY in C++.
 m4_copy([b4_symbol_kind_base], [b4_symbol_kind])
 
+
+# b4_symbol_slot(NUM)
+# -------------------
+# The name of union member that contains the value of these symbols.
+# Currently, we are messy, this should actually be type_tag, but type_tag
+# has several meanings.
+m4_define([b4_symbol_slot],
+[m4_case(b4_percent_define_get([[api.value.type]]),
+         [union],   [b4_symbol([$1], [type_tag])],
+         [variant], [b4_symbol([$1], [type_tag])],
+         [b4_symbol([$1], [type])])])
+
+
 # b4_symbol(NUM, FIELD)
 # ---------------------
 # Fetch FIELD of symbol #NUM (or "orig NUM").  Fail if undefined.
@@ -475,6 +488,7 @@ m4_define([b4_symbol],
          [id],        [b4_symbol_token_kind([$1])],
          [kind_base], [b4_symbol_kind_base([$1])],
          [kind],      [b4_symbol_kind([$1])],
+         [slot],      [b4_symbol_slot([$1])],
          [_b4_symbol($@)])])
 
 

From 0317055bb06d69b74005273955eddaa345cd1eca Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 30 Dec 2020 08:25:39 +0100
Subject: [PATCH 16/26] %merge: clearer tests on diagnostics

* tests/glr-regression.at: Use caret errors.
---
 tests/glr-regression.at | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index f5964756..a6deb9c9 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -1675,11 +1675,19 @@ sym3: %merge<merge> { $$ = 0; } ;
 ]])
 AT_BISON_OPTION_POPDEFS
 
-AT_BISON_CHECK([[-o glr-regr18.c -rall glr-regr18.y]], 1, [],
+AT_BISON_CHECK([[-o glr-regr18.c -rall -fcaret glr-regr18.y]], 1, [],
 [[glr-regr18.y:28.18-24: error: result type clash on merge function 'merge': <type2> != <type1>
+   28 | sym2: sym3 %merge<merge> { $$ = $][1; } ;
+      |                  ^~~~~~~
 glr-regr18.y:27.18-24: note: previous declaration
+   27 | sym1: sym2 %merge<merge> { $$ = $][1; } ;
+      |                  ^~~~~~~
 glr-regr18.y:29.13-19: error: result type clash on merge function 'merge': <type3> != <type2>
+   29 | sym3: %merge<merge> { $$ = 0; } ;
+      |             ^~~~~~~
 glr-regr18.y:28.18-24: note: previous declaration
+   28 | sym2: sym3 %merge<merge> { $$ = $][1; } ;
+      |                  ^~~~~~~
 ]])
 
 AT_CLEANUP

From a26f7cf98fcfe9fa1a3077dafdbff0687c22c039 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 30 Dec 2020 08:27:24 +0100
Subject: [PATCH 17/26] %merge: let mergers record a typing-symbol, rather than
 a type

Symbols are richer than types, and in M4 it is my simpler (and more
common) to deal with symbols rather than types.  So let's associate
mergers to a symbol rather than a type name.

* src/reader.h (merger_list): Replace the 'type' member by a symbol
member.
* src/reader.c (record_merge_function_type): Take a symbol as
argument, rather than a type name.
* src/output.c (merger_output): Adjust.
---
 src/output.c | 14 ++++++--------
 src/reader.c | 29 +++++++++++++++--------------
 src/reader.h |  5 ++++-
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/src/output.c b/src/output.c
index 753b1bd7..19c89cb4 100644
--- a/src/output.c
+++ b/src/output.c
@@ -533,14 +533,12 @@ merger_output (FILE *out)
   int n;
   merger_list* p;
   for (n = 1, p = merge_functions; p != NULL; n += 1, p = p->next)
-    {
-      if (p->type[0] == '\0')
-        fprintf (out, "  case %d: *yy0 = %s (*yy0, *yy1); break;\n",
-                 n, p->name);
-      else
-        fprintf (out, "  case %d: yy0->%s = %s (*yy0, *yy1); break;\n",
-                 n, p->type, p->name);
-    }
+    if (p->sym && p->sym->content->type_name)
+      fprintf (out, "  case %d: yy0->%s = %s (*yy0, *yy1); break;\n",
+               n, p->sym->content->type_name, p->name);
+    else
+      fprintf (out, "  case %d: *yy0 = %s (*yy0, *yy1); break;\n",
+               n, p->name);
   fputs ("]])\n\n", out);
 }
 
diff --git a/src/reader.c b/src/reader.c
index 059e9341..b71dd916 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -41,7 +41,7 @@ static void check_and_convert_grammar (void);
 
 static symbol_list *grammar = NULL;
 static bool start_flag = false;
-merger_list *merge_functions;
+merger_list *merge_functions = NULL;
 
 /* Was %union seen?  */
 bool union_seen = false;
@@ -93,27 +93,27 @@ get_merge_function (uniqstr name)
       syms->next->name = uniqstr_new (name);
       /* After all symbol type declarations have been parsed, packgram invokes
          record_merge_function_type to set the type.  */
-      syms->next->type = NULL;
+      syms->next->sym = NULL;
       syms->next->next = NULL;
       merge_functions = head.next;
     }
   return n;
 }
 
-/*-------------------------------------------------------------------------.
-| For the existing merging function with index MERGER, record the result   |
-| type as TYPE as required by the lhs of the rule whose %merge declaration |
-| is at DECLARATION_LOC.                                                   |
-`-------------------------------------------------------------------------*/
+/*-------------------------------------------------------------------.
+| For the existing merging function with index MERGER, record that   |
+| the result type is that of SYM, as required by the lhs (i.e., SYM) |
+| of the rule whose %merge declaration is at DECLARATION_LOC.        |
+`-------------------------------------------------------------------*/
 
 static void
-record_merge_function_type (int merger, uniqstr type, location declaration_loc)
+record_merge_function_type (int merger, symbol *sym, location declaration_loc)
 {
   if (merger <= 0)
     return;
 
-  if (type == NULL)
-    type = uniqstr_new ("");
+  uniqstr type
+    = sym->content->type_name ? sym->content->type_name : uniqstr_new ("");
 
   merger_list *merge_function;
   int merger_find = 1;
@@ -122,17 +122,18 @@ record_merge_function_type (int merger, uniqstr type, location declaration_loc)
        merge_function = merge_function->next)
     merger_find += 1;
   aver (merge_function != NULL && merger_find == merger);
-  if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
+  if (merge_function->sym && merge_function->sym->content->type_name
+      && !UNIQSTR_EQ (merge_function->sym->content->type_name, type))
     {
       complain (&declaration_loc, complaint,
                 _("result type clash on merge function %s: "
                 "<%s> != <%s>"),
                 quote (merge_function->name), type,
-                merge_function->type);
+                merge_function->sym->content->type_name);
       subcomplain (&merge_function->type_declaration_loc, complaint,
                    _("previous declaration"));
     }
-  merge_function->type = uniqstr_new (type);
+  merge_function->sym = sym;
   merge_function->type_declaration_loc = declaration_loc;
 }
 
@@ -616,7 +617,7 @@ packgram (void)
   for (symbol_list *p = grammar; p; p = p->next)
     {
       symbol_list *lhs = p;
-      record_merge_function_type (lhs->merger, lhs->content.sym->content->type_name,
+      record_merge_function_type (lhs->merger, lhs->content.sym,
                                   lhs->merger_declaration_loc);
       /* If the midrule's $$ is set or its $n is used, remove the '$' from the
          symbol name so that it's a user-defined symbol so that the default
diff --git a/src/reader.h b/src/reader.h
index 6b4f57ff..2fde52c6 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -31,7 +31,10 @@ typedef struct merger_list
 {
   struct merger_list* next;
   uniqstr name;
-  uniqstr type;
+  /* One symbol whose type is the one used by all the symbols on which
+     this merging function is used.  */
+  symbol *sym;
+  /* Where SYM was bound to this merging function.  */
   location type_declaration_loc;
 } merger_list;
 

From 84b00b6bf0e1813f674e16ab3c349e9d7d71904c Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 30 Dec 2020 09:10:05 +0100
Subject: [PATCH 18/26] %merge: delegate the generation of calls to mergers to
 m4

Don't generate C code from bison, leave that to the skeletons.

* src/output.c (merger_output): Emit invocations to b4_call_merger.
* data/skeletons/glr.c (b4_call_merger): New.
---
 data/skeletons/glr.c | 11 ++++++++++-
 src/output.c         |  8 ++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index 5034b5ef..1ef948cd 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -1,4 +1,4 @@
-                                                                    -*- C -*-
+#                                                             -*- C -*-
 
 # GLR skeleton for Bison
 
@@ -145,6 +145,15 @@ m4_define([b4_rhs_location],
 [(b4_rhs_data([$1], [$2]).yyloc)])
 
 
+# b4_call_merger(MERGER-NUM, MERGER-NAME, SYMBOL-SUM)
+# ---------------------------------------------------
+m4_define([b4_call_merger],
+[b4_case([$1],
+         [    b4_symbol_if([$3], [has_type],
+                           [yy0->b4_symbol($3, type) = $2 (*yy0, *yy1);],
+                           [*yy0 = $2 (*yy0, *yy1);])])])
+
+
 ## -------------- ##
 ## Declarations.  ##
 ## -------------- ##
diff --git a/src/output.c b/src/output.c
index 19c89cb4..5c87d5b4 100644
--- a/src/output.c
+++ b/src/output.c
@@ -533,12 +533,8 @@ merger_output (FILE *out)
   int n;
   merger_list* p;
   for (n = 1, p = merge_functions; p != NULL; n += 1, p = p->next)
-    if (p->sym && p->sym->content->type_name)
-      fprintf (out, "  case %d: yy0->%s = %s (*yy0, *yy1); break;\n",
-               n, p->sym->content->type_name, p->name);
-    else
-      fprintf (out, "  case %d: *yy0 = %s (*yy0, *yy1); break;\n",
-               n, p->name);
+    fprintf (out, "]b4_call_merger""([%d], [%s], [%d])[\n",
+             n, p->name, p->sym->content->number);
   fputs ("]])\n\n", out);
 }
 

From 1bac4ecc44f6b7a20b4688b2cb9eeecc91bdb503 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Thu, 31 Dec 2020 07:20:49 +0100
Subject: [PATCH 19/26] %merge: fix compatibility with api.value.type=union

Reported by Jot Dot.
https://lists.gnu.org/r/help-bison/2020-12/msg00014.html

* data/skeletons/glr.c, data/skeletons/glr2.cc (b4_call_merger): Use
the symbol's slot, not its type.
* examples/c/glr/c++-types.y: Use explicit per-symbol typing together
with api.value.type=union.
(yylex): Use yytoken_kind_t.
---
 data/skeletons/glr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index 1ef948cd..b392dd72 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -150,7 +150,7 @@ m4_define([b4_rhs_location],
 m4_define([b4_call_merger],
 [b4_case([$1],
          [    b4_symbol_if([$3], [has_type],
-                           [yy0->b4_symbol($3, type) = $2 (*yy0, *yy1);],
+                           [yy0->b4_symbol($3, slot) = $2 (*yy0, *yy1);],
                            [*yy0 = $2 (*yy0, *yy1);])])])
 
 

From 3abad26a2d0c063719745156dc2d40681c5f969d Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Thu, 31 Dec 2020 07:55:05 +0100
Subject: [PATCH 20/26] %merge: associate it to its first definition, not the
 latest

Currently each time we meet %merge we record this location as the
defining location (and symbol).  Instead, record the first definition.

In the generated code we go from

    yy0->A = merge (*yy0, *yy1);

to

    yy0->S = merge (*yy0, *yy1);

where S was indeed the first symbol, and in the diagnostics we go from

    glr-regr18.y:30.18-24: error: result type clash on merge function 'merge': <type2> != <type1>
       30 | sym2: sym3 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~
    glr-regr18.y:29.18-24: note: previous declaration
       29 | sym1: sym2 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~
    glr-regr18.y:31.13-19: error: result type clash on merge function 'merge': <type3> != <type2>
       31 | sym3: %merge<merge> { $$ = 0; } ;
          |             ^~~~~~~
    glr-regr18.y:30.18-24: note: previous declaration
       30 | sym2: sym3 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~

to

    glr-regr18.y:30.18-24: error: result type clash on merge function 'merge': <type2> != <type1>
       30 | sym2: sym3 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~
    glr-regr18.y:29.18-24: note: previous declaration
       29 | sym1: sym2 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~
    glr-regr18.y:31.13-19: error: result type clash on merge function 'merge': <type3> != <type1>
       31 | sym3: %merge<merge> { $$ = 0; } ;
          |             ^~~~~~~
    glr-regr18.y:29.18-24: note: previous declaration
       29 | sym1: sym2 %merge<merge> { $$ = $1; } ;
          |                  ^~~~~~~

where both duplicates are reported against definition 1, rather than
using definition 1 as a reference when diagnosing about definition 2,
and then 2 as a reference for 3.

* src/reader.c (record_merge_function_type): Keep the first definition.
* tests/glr-regression.at: Adjust.
---
 src/reader.c            | 27 ++++++++++++++++-----------
 tests/glr-regression.at |  6 +++---
 2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/src/reader.c b/src/reader.c
index b71dd916..a43c5e41 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -122,19 +122,24 @@ record_merge_function_type (int merger, symbol *sym, location declaration_loc)
        merge_function = merge_function->next)
     merger_find += 1;
   aver (merge_function != NULL && merger_find == merger);
-  if (merge_function->sym && merge_function->sym->content->type_name
-      && !UNIQSTR_EQ (merge_function->sym->content->type_name, type))
+  if (merge_function->sym && merge_function->sym->content->type_name)
     {
-      complain (&declaration_loc, complaint,
-                _("result type clash on merge function %s: "
-                "<%s> != <%s>"),
-                quote (merge_function->name), type,
-                merge_function->sym->content->type_name);
-      subcomplain (&merge_function->type_declaration_loc, complaint,
-                   _("previous declaration"));
+      if (!UNIQSTR_EQ (merge_function->sym->content->type_name, type))
+        {
+          complain (&declaration_loc, complaint,
+                    _("result type clash on merge function %s: "
+                      "<%s> != <%s>"),
+                    quote (merge_function->name), type,
+                    merge_function->sym->content->type_name);
+          subcomplain (&merge_function->type_declaration_loc, complaint,
+                       _("previous declaration"));
+        }
+    }
+  else
+    {
+      merge_function->sym = sym;
+      merge_function->type_declaration_loc = declaration_loc;
     }
-  merge_function->sym = sym;
-  merge_function->type_declaration_loc = declaration_loc;
 }
 
 /*--------------------------------------.
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index a6deb9c9..51c6ee5e 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -1682,11 +1682,11 @@ AT_BISON_CHECK([[-o glr-regr18.c -rall -fcaret glr-regr18.y]], 1, [],
 glr-regr18.y:27.18-24: note: previous declaration
    27 | sym1: sym2 %merge<merge> { $$ = $][1; } ;
       |                  ^~~~~~~
-glr-regr18.y:29.13-19: error: result type clash on merge function 'merge': <type3> != <type2>
+glr-regr18.y:29.13-19: error: result type clash on merge function 'merge': <type3> != <type1>
    29 | sym3: %merge<merge> { $$ = 0; } ;
       |             ^~~~~~~
-glr-regr18.y:28.18-24: note: previous declaration
-   28 | sym2: sym3 %merge<merge> { $$ = $][1; } ;
+glr-regr18.y:27.18-24: note: previous declaration
+   27 | sym1: sym2 %merge<merge> { $$ = $][1; } ;
       |                  ^~~~~~~
 ]])
 

From 003ca0498d6bc7f1d36d566b26555c4b48f723cf Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 16 Jan 2021 16:00:37 +0100
Subject: [PATCH 21/26] package: bump copyrights to 2021

Run 'make update-copyright'.
---
 AUTHORS                                   |  2 +-
 ChangeLog-2012                            |  2 +-
 Makefile.am                               |  2 +-
 NEWS                                      |  2 +-
 PACKAGING                                 |  2 +-
 README                                    |  2 +-
 README-alpha                              |  2 +-
 README-hacking.md                         |  2 +-
 THANKS                                    |  2 +-
 TODO                                      |  2 +-
 bootstrap.conf                            |  2 +-
 build-aux/Darwin.valgrind                 |  2 +-
 build-aux/Linux.valgrind                  |  2 +-
 build-aux/cross-options.pl                |  2 +-
 build-aux/local.mk                        |  2 +-
 build-aux/update-b4-copyright             |  2 +-
 build-aux/update-package-copyright-year   |  2 +-
 build-aux/update-test                     |  2 +-
 cfg.mk                                    |  2 +-
 configure.ac                              |  4 ++--
 data/README.md                            |  2 +-
 data/bison-default.css                    |  2 +-
 data/local.mk                             |  2 +-
 data/skeletons/bison.m4                   |  2 +-
 data/skeletons/c++-skel.m4                |  2 +-
 data/skeletons/c++.m4                     |  2 +-
 data/skeletons/c-like.m4                  |  2 +-
 data/skeletons/c-skel.m4                  |  2 +-
 data/skeletons/c.m4                       |  2 +-
 data/skeletons/d-skel.m4                  |  2 +-
 data/skeletons/d.m4                       |  2 +-
 data/skeletons/glr.c                      |  6 +++---
 data/skeletons/glr.cc                     |  4 ++--
 data/skeletons/java-skel.m4               |  2 +-
 data/skeletons/java.m4                    |  2 +-
 data/skeletons/lalr1.cc                   |  4 ++--
 data/skeletons/lalr1.d                    |  4 ++--
 data/skeletons/lalr1.java                 |  4 ++--
 data/skeletons/location.cc                |  4 ++--
 data/skeletons/stack.hh                   |  2 +-
 data/skeletons/variant.hh                 |  2 +-
 data/skeletons/yacc.c                     |  4 ++--
 data/xslt/bison.xsl                       |  2 +-
 data/xslt/xml2dot.xsl                     |  2 +-
 data/xslt/xml2text.xsl                    |  2 +-
 data/xslt/xml2xhtml.xsl                   |  2 +-
 doc/bison.texi                            | 20 ++++++++++----------
 doc/local.mk                              |  2 +-
 doc/refcard.tex                           |  2 +-
 etc/README.md                             |  2 +-
 etc/bench.pl.in                           |  2 +-
 etc/local.mk                              |  2 +-
 examples/README.md                        |  2 +-
 examples/c++/README.md                    |  2 +-
 examples/c++/calc++/README.md             |  2 +-
 examples/c++/calc++/calc++.test           |  2 +-
 examples/c++/calc++/local.mk              |  2 +-
 examples/c++/local.mk                     |  2 +-
 examples/c++/variant-11.test              |  2 +-
 examples/c++/variant-11.yy                |  2 +-
 examples/c++/variant.test                 |  2 +-
 examples/c++/variant.yy                   |  2 +-
 examples/c/README.md                      |  2 +-
 examples/c/bistromathic/README.md         |  2 +-
 examples/c/bistromathic/bistromathic.test |  2 +-
 examples/c/bistromathic/local.mk          |  2 +-
 examples/c/bistromathic/parse.y           |  2 +-
 examples/c/calc/README.md                 |  2 +-
 examples/c/calc/calc.test                 |  2 +-
 examples/c/calc/local.mk                  |  2 +-
 examples/c/lexcalc/README.md              |  2 +-
 examples/c/lexcalc/lexcalc.test           |  2 +-
 examples/c/lexcalc/local.mk               |  2 +-
 examples/c/lexcalc/parse.y                |  2 +-
 examples/c/lexcalc/scan.l                 |  2 +-
 examples/c/local.mk                       |  2 +-
 examples/c/mfcalc/local.mk                |  2 +-
 examples/c/mfcalc/mfcalc.test             |  2 +-
 examples/c/pushcalc/README.md             |  2 +-
 examples/c/pushcalc/calc.test             |  2 +-
 examples/c/pushcalc/calc.y                |  2 +-
 examples/c/pushcalc/local.mk              |  2 +-
 examples/c/reccalc/README.md              |  2 +-
 examples/c/reccalc/local.mk               |  2 +-
 examples/c/reccalc/parse.y                |  2 +-
 examples/c/reccalc/reccalc.test           |  2 +-
 examples/c/reccalc/scan.l                 |  2 +-
 examples/c/rpcalc/local.mk                |  2 +-
 examples/c/rpcalc/rpcalc.test             |  2 +-
 examples/d/README.md                      |  2 +-
 examples/d/calc.test                      |  2 +-
 examples/d/calc.y                         |  2 +-
 examples/d/local.mk                       |  2 +-
 examples/extexi                           |  2 +-
 examples/java/README.md                   |  2 +-
 examples/java/calc/Calc.test              |  2 +-
 examples/java/calc/Calc.y                 |  2 +-
 examples/java/calc/local.mk               |  2 +-
 examples/java/local.mk                    |  2 +-
 examples/java/simple/Calc.test            |  2 +-
 examples/java/simple/Calc.y               |  2 +-
 examples/java/simple/local.mk             |  2 +-
 examples/local.mk                         |  2 +-
 examples/test                             |  2 +-
 lib/get-errno.c                           |  2 +-
 lib/get-errno.h                           |  2 +-
 lib/local.mk                              |  2 +-
 lib/main.c                                |  2 +-
 lib/path-join.c                           |  2 +-
 lib/path-join.h                           |  2 +-
 lib/timevar.def                           |  2 +-
 lib/yyerror.c                             |  2 +-
 m4/bison-check-compiler-flag.m4           |  2 +-
 m4/bison-cxx-std.m4                       |  2 +-
 m4/bison-i18n.m4                          |  2 +-
 m4/c-working.m4                           |  2 +-
 m4/cxx.m4                                 |  2 +-
 m4/flex.m4                                |  2 +-
 src/AnnotationList.c                      |  2 +-
 src/AnnotationList.h                      |  2 +-
 src/InadequacyList.c                      |  2 +-
 src/InadequacyList.h                      |  2 +-
 src/Sbitset.c                             |  2 +-
 src/Sbitset.h                             |  2 +-
 src/assoc.c                               |  2 +-
 src/assoc.h                               |  2 +-
 src/closure.c                             |  2 +-
 src/closure.h                             |  2 +-
 src/complain.c                            |  2 +-
 src/complain.h                            |  2 +-
 src/conflicts.c                           |  2 +-
 src/conflicts.h                           |  2 +-
 src/counterexample.c                      |  2 +-
 src/counterexample.h                      |  2 +-
 src/derivation.c                          |  2 +-
 src/derivation.h                          |  2 +-
 src/derives.c                             |  2 +-
 src/derives.h                             |  2 +-
 src/files.c                               |  2 +-
 src/files.h                               |  2 +-
 src/fixits.c                              |  2 +-
 src/fixits.h                              |  2 +-
 src/flex-scanner.h                        |  2 +-
 src/getargs.c                             |  2 +-
 src/getargs.h                             |  2 +-
 src/glyphs.c                              |  2 +-
 src/glyphs.h                              |  2 +-
 src/gram.c                                |  2 +-
 src/gram.h                                |  2 +-
 src/graphviz.c                            |  2 +-
 src/graphviz.h                            |  2 +-
 src/ielr.c                                |  2 +-
 src/ielr.h                                |  2 +-
 src/lalr.c                                |  2 +-
 src/lalr.h                                |  2 +-
 src/local.mk                              |  2 +-
 src/location.c                            |  2 +-
 src/location.h                            |  2 +-
 src/lr0.c                                 |  2 +-
 src/lr0.h                                 |  2 +-
 src/lssi.c                                |  2 +-
 src/lssi.h                                |  2 +-
 src/main.c                                |  2 +-
 src/muscle-tab.c                          |  2 +-
 src/muscle-tab.h                          |  2 +-
 src/named-ref.c                           |  2 +-
 src/named-ref.h                           |  2 +-
 src/nullable.c                            |  2 +-
 src/nullable.h                            |  2 +-
 src/output.c                              |  2 +-
 src/output.h                              |  2 +-
 src/parse-gram.c                          |  2 +-
 src/parse-gram.h                          |  2 +-
 src/parse-gram.y                          |  2 +-
 src/parse-simulation.c                    |  2 +-
 src/parse-simulation.h                    |  2 +-
 src/print-graph.c                         |  2 +-
 src/print-graph.h                         |  2 +-
 src/print-xml.c                           |  2 +-
 src/print-xml.h                           |  2 +-
 src/print.c                               |  2 +-
 src/print.h                               |  2 +-
 src/reader.c                              |  2 +-
 src/reader.h                              |  2 +-
 src/reduce.c                              |  2 +-
 src/reduce.h                              |  2 +-
 src/relation.c                            |  2 +-
 src/relation.h                            |  2 +-
 src/scan-code.h                           |  2 +-
 src/scan-code.l                           |  2 +-
 src/scan-gram.h                           |  2 +-
 src/scan-gram.l                           |  2 +-
 src/scan-skel.h                           |  2 +-
 src/scan-skel.l                           |  2 +-
 src/state-item.c                          |  2 +-
 src/state-item.h                          |  2 +-
 src/state.c                               |  2 +-
 src/state.h                               |  2 +-
 src/strversion.c                          |  2 +-
 src/strversion.h                          |  2 +-
 src/symlist.c                             |  2 +-
 src/symlist.h                             |  2 +-
 src/symtab.c                              |  2 +-
 src/symtab.h                              |  2 +-
 src/system.h                              |  2 +-
 src/tables.c                              |  2 +-
 src/tables.h                              |  2 +-
 src/uniqstr.c                             |  2 +-
 src/uniqstr.h                             |  2 +-
 tests/actions.at                          |  2 +-
 tests/atlocal.in                          |  2 +-
 tests/bison.in                            |  2 +-
 tests/c++.at                              |  2 +-
 tests/calc.at                             |  2 +-
 tests/conflicts.at                        |  2 +-
 tests/counterexample.at                   |  2 +-
 tests/cxx-type.at                         |  2 +-
 tests/diagnostics.at                      |  2 +-
 tests/existing.at                         |  2 +-
 tests/glr-regression.at                   |  2 +-
 tests/headers.at                          |  2 +-
 tests/input.at                            |  2 +-
 tests/java.at                             |  2 +-
 tests/javapush.at                         |  2 +-
 tests/linear                              |  2 +-
 tests/local.at                            |  2 +-
 tests/local.mk                            |  2 +-
 tests/m4.at                               |  2 +-
 tests/named-refs.at                       |  2 +-
 tests/output.at                           |  2 +-
 tests/push.at                             |  2 +-
 tests/reduce.at                           |  2 +-
 tests/regression.at                       |  2 +-
 tests/report.at                           |  2 +-
 tests/scanner.at                          |  2 +-
 tests/sets.at                             |  2 +-
 tests/skeletons.at                        |  2 +-
 tests/synclines.at                        |  2 +-
 tests/testsuite.at                        |  2 +-
 tests/torture.at                          |  2 +-
 tests/types.at                            |  2 +-
 241 files changed, 259 insertions(+), 259 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index e624c51b..5991853d 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -24,7 +24,7 @@ and nasty bugs.
 
 -----
 
-Copyright (C) 1998-2015, 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 1998-2015, 2018-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/ChangeLog-2012 b/ChangeLog-2012
index d56c1267..6ff8f0d7 100644
--- a/ChangeLog-2012
+++ b/ChangeLog-2012
@@ -26733,7 +26733,7 @@
 
 	-----
 
-	Copyright (C) 1987-1988, 1991-2015, 2018-2020 Free Software
+	Copyright (C) 1987-1988, 1991-2015, 2018-2021 Free Software
 	Foundation, Inc.
 
 	Copying and distribution of this file, with or without
diff --git a/Makefile.am b/Makefile.am
index f94842c4..451af962 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
 ## Process this file with automake to produce Makefile.in.
 
-# Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/NEWS b/NEWS
index 1fd12f9f..e9715723 100644
--- a/NEWS
+++ b/NEWS
@@ -4554,7 +4554,7 @@ mode: outline
 fill-column: 76
 End:
 
-Copyright (C) 1995-2015, 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 1995-2015, 2018-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Parser Generator.
 
diff --git a/PACKAGING b/PACKAGING
index d4bf6d84..69bfc96e 100644
--- a/PACKAGING
+++ b/PACKAGING
@@ -36,7 +36,7 @@ to the bison package.
 
 -----
 
-Copyright (C) 2002, 2005, 2009-2015, 2018-2020 Free Software Foundation,
+Copyright (C) 2002, 2005, 2009-2015, 2018-2021 Free Software Foundation,
 Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
diff --git a/README b/README
index 94f8a4f8..e97c65a6 100644
--- a/README
+++ b/README
@@ -120,7 +120,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 1992, 1998-1999, 2003-2005, 2008-2015, 2018-2020 Free
+Copyright (C) 1992, 1998-1999, 2003-2005, 2008-2015, 2018-2021 Free
 Software Foundation, Inc.
 
 This file is part of GNU bison, the GNU Compiler Compiler.
diff --git a/README-alpha b/README-alpha
index dbd0e88e..3dff3b2e 100644
--- a/README-alpha
+++ b/README-alpha
@@ -12,7 +12,7 @@ the problems you encounter.
 
 -----
 
-Copyright (C) 2002, 2004, 2009-2015, 2018-2020 Free Software Foundation,
+Copyright (C) 2002, 2004, 2009-2015, 2018-2021 Free Software Foundation,
 Inc.
 
 This file is part of GNU Bison.
diff --git a/README-hacking.md b/README-hacking.md
index b5245bb9..85bc7376 100644
--- a/README-hacking.md
+++ b/README-hacking.md
@@ -569,7 +569,7 @@ bootstrapped.
 
 <!--
 
-Copyright (C) 2002-2005, 2007-2015, 2018-2020 Free Software Foundation,
+Copyright (C) 2002-2005, 2007-2015, 2018-2021 Free Software Foundation,
 Inc.
 
 This file is part of GNU Bison.
diff --git a/THANKS b/THANKS
index 195153a6..d3b34c75 100644
--- a/THANKS
+++ b/THANKS
@@ -237,7 +237,7 @@ End:
 
 -----
 
-Copyright (C) 2000-2015, 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2000-2015, 2018-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Parser Generator.
 
diff --git a/TODO b/TODO
index e9874678..20893436 100644
--- a/TODO
+++ b/TODO
@@ -877,7 +877,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2001-2004, 2006, 2008-2015, 2018-2020 Free Software
+Copyright (C) 2001-2004, 2006, 2008-2015, 2018-2021 Free Software
 Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
diff --git a/bootstrap.conf b/bootstrap.conf
index 577e30e5..a5180d61 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -1,6 +1,6 @@
 # Bootstrap configuration.
 
-# Copyright (C) 2006-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2006-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/Darwin.valgrind b/build-aux/Darwin.valgrind
index dec3b341..cb8b4973 100644
--- a/build-aux/Darwin.valgrind
+++ b/build-aux/Darwin.valgrind
@@ -1,4 +1,4 @@
-# Copyright (C) 2012-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2012-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/Linux.valgrind b/build-aux/Linux.valgrind
index a7ebd2c7..2e0290f8 100644
--- a/build-aux/Linux.valgrind
+++ b/build-aux/Linux.valgrind
@@ -1,4 +1,4 @@
-# Copyright (C) 2012-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2012-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/cross-options.pl b/build-aux/cross-options.pl
index 31fe8065..754b4ee7 100755
--- a/build-aux/cross-options.pl
+++ b/build-aux/cross-options.pl
@@ -2,7 +2,7 @@
 
 # Generate a release announcement message.
 
-# Copyright (C) 2007-2020 Free Software Foundation, Inc.
+# Copyright (C) 2007-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/local.mk b/build-aux/local.mk
index 8030dec2..d95eaaaf 100644
--- a/build-aux/local.mk
+++ b/build-aux/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2000-2015, 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2000-2015, 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/build-aux/update-b4-copyright b/build-aux/update-b4-copyright
index 85646436..86aa1014 100755
--- a/build-aux/update-b4-copyright
+++ b/build-aux/update-b4-copyright
@@ -3,7 +3,7 @@
 # Update b4_copyright invocations or b4_copyright_years definitions to
 # include the current year.
 
-# Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/update-package-copyright-year b/build-aux/update-package-copyright-year
index ad27b0ce..ba7297a7 100755
--- a/build-aux/update-package-copyright-year
+++ b/build-aux/update-package-copyright-year
@@ -2,7 +2,7 @@
 
 # In configure.ac, update PACKAGE_COPYRIGHT_YEAR to the current year.
 
-# Copyright (C) 2010-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2010-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/build-aux/update-test b/build-aux/update-test
index d63a95e4..dd73e25a 100755
--- a/build-aux/update-test
+++ b/build-aux/update-test
@@ -2,7 +2,7 @@
 
 # Update expectations in an Autotest test suite.
 
-# Copyright (C) 2019-2020 Free Software Foundation, Inc.
+# Copyright (C) 2019-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/cfg.mk b/cfg.mk
index 114aa814..6725a186 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -1,5 +1,5 @@
 ## Customize maint.mk                           -*- makefile -*-
-## Copyright (C) 2008-2015, 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2008-2015, 2018-2021 Free Software Foundation, Inc.
 
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/configure.ac b/configure.ac
index 4993a2c6..b1258fca 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
 # Configure template for GNU Bison.                   -*-Autoconf-*-
 #
-# Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -29,7 +29,7 @@ AC_INIT([GNU Bison],
         [bug-bison@gnu.org],
         [],
         [https://www.gnu.org/software/bison/])
-AC_SUBST([PACKAGE_COPYRIGHT_YEAR], [2020])
+AC_SUBST([PACKAGE_COPYRIGHT_YEAR], [2021])
 AC_DEFINE_UNQUOTED([PACKAGE_COPYRIGHT_YEAR], [$PACKAGE_COPYRIGHT_YEAR],
                    [The copyright year for this package])
 
diff --git a/data/README.md b/data/README.md
index 59b220b0..e6d985da 100644
--- a/data/README.md
+++ b/data/README.md
@@ -193,7 +193,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2002, 2008-2015, 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2002, 2008-2015, 2018-2021 Free Software Foundation, Inc.
 
 This file is part of GNU Bison.
 
diff --git a/data/bison-default.css b/data/bison-default.css
index 21e672d2..aadaba17 100644
--- a/data/bison-default.css
+++ b/data/bison-default.css
@@ -1,5 +1,5 @@
 /* Default styling rules for Bison when doing terminal output.
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/data/local.mk b/data/local.mk
index 21106451..67d25180 100644
--- a/data/local.mk
+++ b/data/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2002, 2005-2015, 2018-2020 Free Software Foundation,
+## Copyright (C) 2002, 2005-2015, 2018-2021 Free Software Foundation,
 ## Inc.
 
 ## This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/bison.m4 b/data/skeletons/bison.m4
index 156b0689..5938bd75 100644
--- a/data/skeletons/bison.m4
+++ b/data/skeletons/bison.m4
@@ -2,7 +2,7 @@
 
 # Language-independent M4 Macros for Bison.
 
-# Copyright (C) 2002, 2004-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2002, 2004-2015, 2018-2021 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/c++-skel.m4 b/data/skeletons/c++-skel.m4
index 6d3becf5..01ee793f 100644
--- a/data/skeletons/c++-skel.m4
+++ b/data/skeletons/c++-skel.m4
@@ -2,7 +2,7 @@
 
 # C++ skeleton dispatching for Bison.
 
-# Copyright (C) 2006-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/c++.m4 b/data/skeletons/c++.m4
index 5081273f..bd1a27bb 100644
--- a/data/skeletons/c++.m4
+++ b/data/skeletons/c++.m4
@@ -2,7 +2,7 @@
 
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/c-like.m4 b/data/skeletons/c-like.m4
index 1e5ab02c..d45b708b 100644
--- a/data/skeletons/c-like.m4
+++ b/data/skeletons/c-like.m4
@@ -2,7 +2,7 @@
 
 # Common code for C-like languages (C, C++, Java, etc.)
 
-# Copyright (C) 2012-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2012-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/c-skel.m4 b/data/skeletons/c-skel.m4
index 68d057cb..4f1e5a83 100644
--- a/data/skeletons/c-skel.m4
+++ b/data/skeletons/c-skel.m4
@@ -2,7 +2,7 @@
 
 # C skeleton dispatching for Bison.
 
-# Copyright (C) 2006-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/c.m4 b/data/skeletons/c.m4
index 8a5c851b..722fa7dc 100644
--- a/data/skeletons/c.m4
+++ b/data/skeletons/c.m4
@@ -2,7 +2,7 @@
 
 # C M4 Macros for Bison.
 
-# Copyright (C) 2002, 2004-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2002, 2004-2015, 2018-2021 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/d-skel.m4 b/data/skeletons/d-skel.m4
index 89cd5114..c3943f78 100644
--- a/data/skeletons/d-skel.m4
+++ b/data/skeletons/d-skel.m4
@@ -2,7 +2,7 @@
 
 # D skeleton dispatching for Bison.
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/d.m4 b/data/skeletons/d.m4
index 0c283519..8633a6b5 100644
--- a/data/skeletons/d.m4
+++ b/data/skeletons/d.m4
@@ -2,7 +2,7 @@
 
 # D language support for Bison
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index b392dd72..e93aa5ac 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -2,7 +2,7 @@
 
 # GLR skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -197,7 +197,7 @@ b4_glr_cc_if([],
 [b4_defines_if(
 [b4_output_begin([b4_spec_header_file])
 b4_copyright([Skeleton interface for Bison GLR parsers in C],
-             [2002-2015, 2018-2020])[
+             [2002-2015, 2018-2021])[
 ]b4_cpp_guard_open([b4_spec_mapped_header_file])[
 ]b4_shared_declarations[
 ]b4_cpp_guard_close([b4_spec_mapped_header_file])[
@@ -211,7 +211,7 @@ b4_copyright([Skeleton interface for Bison GLR parsers in C],
 
 b4_output_begin([b4_parser_file_name])
 b4_copyright([Skeleton implementation for Bison GLR parsers in C],
-             [2002-2015, 2018-2020])[
+             [2002-2015, 2018-2021])[
 /* C GLR parser skeleton written by Paul Hilfinger.  */
 
 ]b4_disclaimer[
diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index cfff9773..40366172 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -1,6 +1,6 @@
 # C++ GLR skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -381,7 +381,7 @@ b4_percent_code_get([[requires]])[
 ]b4_defines_if(
 [b4_output_begin([b4_spec_header_file])
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
-             [2002-2015, 2018-2020])[
+             [2002-2015, 2018-2021])[
 // C++ GLR parser skeleton written by Akim Demaille.
 
 ]b4_disclaimer[
diff --git a/data/skeletons/java-skel.m4 b/data/skeletons/java-skel.m4
index bcc8ebde..0e59220c 100644
--- a/data/skeletons/java-skel.m4
+++ b/data/skeletons/java-skel.m4
@@ -2,7 +2,7 @@
 
 # Java skeleton dispatching for Bison.
 
-# Copyright (C) 2007, 2009-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2007, 2009-2015, 2018-2021 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/data/skeletons/java.m4 b/data/skeletons/java.m4
index 7b4f7b5c..57a69b78 100644
--- a/data/skeletons/java.m4
+++ b/data/skeletons/java.m4
@@ -2,7 +2,7 @@
 
 # Java language support for Bison
 
-# Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/lalr1.cc b/data/skeletons/lalr1.cc
index c62c77d2..1374d107 100644
--- a/data/skeletons/lalr1.cc
+++ b/data/skeletons/lalr1.cc
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -160,7 +160,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))])])
 
 
 m4_pushdef([b4_copyright_years],
-           [2002-2015, 2018-2020])
+           [2002-2015, 2018-2021])
 
 m4_define([b4_parser_class],
           [b4_percent_define_get([[api.parser.class]])])
diff --git a/data/skeletons/lalr1.d b/data/skeletons/lalr1.d
index 761125cb..1a44bef8 100644
--- a/data/skeletons/lalr1.d
+++ b/data/skeletons/lalr1.d
@@ -1,6 +1,6 @@
 # D skeleton for Bison -*- autoconf -*-
 
-# Copyright (C) 2007-2012, 2019-2020 Free Software Foundation, Inc.
+# Copyright (C) 2007-2012, 2019-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -20,7 +20,7 @@ m4_include(b4_skeletonsdir/[d.m4])
 
 b4_output_begin([b4_parser_file_name])
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in D],
-             [2007-2012, 2019-2020])[
+             [2007-2012, 2019-2021])[
 ]b4_disclaimer[
 ]b4_percent_define_ifdef([package], [module b4_percent_define_get([package]);
 ])[
diff --git a/data/skeletons/lalr1.java b/data/skeletons/lalr1.java
index b85c16a0..9e3ef829 100644
--- a/data/skeletons/lalr1.java
+++ b/data/skeletons/lalr1.java
@@ -1,6 +1,6 @@
 # Java skeleton for Bison                           -*- autoconf -*-
 
-# Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -78,7 +78,7 @@ m4_define([b4_define_state],[[
 
 ]b4_output_begin([b4_parser_file_name])[
 ]b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
-              [2007-2015, 2018-2020])[
+              [2007-2015, 2018-2021])[
 ]b4_disclaimer[
 ]b4_percent_define_ifdef([api.package], [package b4_percent_define_get([api.package]);[
 ]])[
diff --git a/data/skeletons/location.cc b/data/skeletons/location.cc
index c96381e9..4ae5531f 100644
--- a/data/skeletons/location.cc
+++ b/data/skeletons/location.cc
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -16,7 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 m4_pushdef([b4_copyright_years],
-           [2002-2015, 2018-2020])
+           [2002-2015, 2018-2021])
 
 
 # b4_position_file
diff --git a/data/skeletons/stack.hh b/data/skeletons/stack.hh
index 38bff8ba..2b85ea93 100644
--- a/data/skeletons/stack.hh
+++ b/data/skeletons/stack.hh
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/variant.hh b/data/skeletons/variant.hh
index 2887ba61..a29b4b81 100644
--- a/data/skeletons/variant.hh
+++ b/data/skeletons/variant.hh
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/skeletons/yacc.c b/data/skeletons/yacc.c
index c695a039..6aa3f524 100644
--- a/data/skeletons/yacc.c
+++ b/data/skeletons/yacc.c
@@ -1,11 +1,11 @@
 #                                                            -*- C -*-
 # Yacc compatible skeleton for Bison
 
-# Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2020 Free Software
+# Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 m4_pushdef([b4_copyright_years],
-           [1984, 1989-1990, 2000-2015, 2018-2020])
+           [1984, 1989-1990, 2000-2015, 2018-2021])
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/data/xslt/bison.xsl b/data/xslt/bison.xsl
index d4936959..2cf8d13b 100644
--- a/data/xslt/bison.xsl
+++ b/data/xslt/bison.xsl
@@ -3,7 +3,7 @@
 <!--
     bison.xsl - common templates for Bison XSLT.
 
-    Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+    Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
     This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/data/xslt/xml2dot.xsl b/data/xslt/xml2dot.xsl
index a8a5edff..2933358f 100644
--- a/data/xslt/xml2dot.xsl
+++ b/data/xslt/xml2dot.xsl
@@ -3,7 +3,7 @@
 <!--
     xml2dot.xsl - transform Bison XML Report into DOT.
 
-    Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+    Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
     This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/data/xslt/xml2text.xsl b/data/xslt/xml2text.xsl
index 6aad1526..a6207480 100644
--- a/data/xslt/xml2text.xsl
+++ b/data/xslt/xml2text.xsl
@@ -3,7 +3,7 @@
 <!--
     xml2text.xsl - transform Bison XML Report into plain text.
 
-    Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+    Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
     This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/data/xslt/xml2xhtml.xsl b/data/xslt/xml2xhtml.xsl
index 5fcfda67..e869c1c3 100644
--- a/data/xslt/xml2xhtml.xsl
+++ b/data/xslt/xml2xhtml.xsl
@@ -3,7 +3,7 @@
 <!--
     xml2html.xsl - transform Bison XML Report into XHTML.
 
-    Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+    Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
     This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/doc/bison.texi b/doc/bison.texi
index 4e9bb58b..0cb75060 100644
--- a/doc/bison.texi
+++ b/doc/bison.texi
@@ -173,7 +173,7 @@
 This manual (@value{UPDATED}) is for GNU Bison (version @value{VERSION}),
 the GNU parser generator.
 
-Copyright @copyright{} 1988--1993, 1995, 1998--2015, 2018--2020 Free
+Copyright @copyright{} 1988--1993, 1995, 1998--2015, 2018--2021 Free
 Software Foundation, Inc.
 
 @quotation
@@ -1663,7 +1663,7 @@ after @samp{//}.
 @example
 /* Parser for rpcalc.   -*- C -*-
 
-   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2020 Free Software
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -2549,7 +2549,7 @@ Here are the C and Bison declarations for the multi-function calculator.
 @example
 /* Parser for mfcalc.   -*- C -*-
 
-   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2020 Free Software
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -2678,7 +2678,7 @@ provides for either functions or variables to be placed in the table.
 @example
 /* Functions for mfcalc.   -*- C -*-
 
-   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2020 Free Software
+   Copyright (C) 1988-1993, 1995, 1998-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -11988,7 +11988,7 @@ generate C++.
 @example
 /* Simple variant-based parser.   -*- C++ -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -13084,7 +13084,7 @@ library components, and the declaration of the parser class.
 @example
 /* Driver for calc++.   -*- C++ -*-
 
-   Copyright (C) 2005--2015, 2018--2020 Free Software Foundation, Inc.
+   Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -13180,7 +13180,7 @@ The implementation of the driver (@file{driver.cc}) is straightforward.
 @example
 /* Driver for calc++.   -*- C++ -*-
 
-   Copyright (C) 2005--2015, 2018--2020 Free Software Foundation, Inc.
+   Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -13247,7 +13247,7 @@ designed the grammar for.
 @example
 /* Parser for calc++.   -*- C++ -*-
 
-   Copyright (C) 2005--2015, 2018--2020 Free Software Foundation, Inc.
+   Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -13459,7 +13459,7 @@ then the parser's to get the set of defined tokens.
 @example
 /* Scanner for calc++.   -*- C++ -*-
 
-   Copyright (C) 2005--2015, 2018--2020 Free Software Foundation, Inc.
+   Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -13714,7 +13714,7 @@ The top level file, @file{calc++.cc}, poses no problem.
 @example
 /* Main for calc++.   -*- C++ -*-
 
-   Copyright (C) 2005--2015, 2018--2020 Free Software Foundation, Inc.
+   Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/doc/local.mk b/doc/local.mk
index f5590015..f78501b6 100644
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2001-2003, 2005-2015, 2018-2020 Free Software
+## Copyright (C) 2001-2003, 2005-2015, 2018-2021 Free Software
 ## Foundation, Inc.
 
 ## This program is free software: you can redistribute it and/or modify
diff --git a/doc/refcard.tex b/doc/refcard.tex
index 23fd9a61..20cdc067 100644
--- a/doc/refcard.tex
+++ b/doc/refcard.tex
@@ -19,7 +19,7 @@
 \def\finalout{\overfullrule=0pt}
 %\finalout
 
-% Copyright (c) 1998, 2001, 2009--2015, 2018--2020 Free Software
+% Copyright (c) 1998, 2001, 2009--2015, 2018--2021 Free Software
 % Foundation, Inc.
 %
 % This file is part of Bison.
diff --git a/etc/README.md b/etc/README.md
index c7c67b4a..996b640d 100644
--- a/etc/README.md
+++ b/etc/README.md
@@ -22,7 +22,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2006, 2009-2015, 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2006, 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/etc/bench.pl.in b/etc/bench.pl.in
index 96a92fb6..22452120 100755
--- a/etc/bench.pl.in
+++ b/etc/bench.pl.in
@@ -1,6 +1,6 @@
 #! /usr/bin/perl -w
 
-# Copyright (C) 2006, 2008-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2006, 2008-2015, 2018-2021 Free Software Foundation,
 # Inc.
 #
 # This file is part of Bison, the GNU Compiler Compiler.
diff --git a/etc/local.mk b/etc/local.mk
index d03db45f..b62416ea 100644
--- a/etc/local.mk
+++ b/etc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2006, 2008-2015, 2018-2020 Free Software Foundation,
+## Copyright (C) 2006, 2008-2015, 2018-2021 Free Software Foundation,
 ## Inc.
 
 ## This program is free software: you can redistribute it and/or modify
diff --git a/examples/README.md b/examples/README.md
index bfd14fad..cc467dc0 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -17,7 +17,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/c++/README.md b/examples/c++/README.md
index cbef0021..93cd09d5 100644
--- a/examples/c++/README.md
+++ b/examples/c++/README.md
@@ -46,7 +46,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/c++/calc++/README.md b/examples/c++/calc++/README.md
index 2c0a8363..6aaebc2a 100644
--- a/examples/c++/calc++/README.md
+++ b/examples/c++/calc++/README.md
@@ -36,7 +36,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/c++/calc++/calc++.test b/examples/c++/calc++/calc++.test
index e00bb466..5e084856 100755
--- a/examples/c++/calc++/calc++.test
+++ b/examples/c++/calc++/calc++.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2005-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c++/calc++/local.mk b/examples/c++/calc++/local.mk
index 00f47a48..6159f553 100644
--- a/examples/c++/calc++/local.mk
+++ b/examples/c++/calc++/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2005-2006, 2008-2015, 2018-2020 Free Software
+## Copyright (C) 2005-2006, 2008-2015, 2018-2021 Free Software
 ## Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
diff --git a/examples/c++/local.mk b/examples/c++/local.mk
index a41613fd..4746c8fb 100644
--- a/examples/c++/local.mk
+++ b/examples/c++/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c++/variant-11.test b/examples/c++/variant-11.test
index aa39315b..c1e13215 100644
--- a/examples/c++/variant-11.test
+++ b/examples/c++/variant-11.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c++/variant-11.yy b/examples/c++/variant-11.yy
index 7d883232..adcd7e30 100644
--- a/examples/c++/variant-11.yy
+++ b/examples/c++/variant-11.yy
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2008-2015, 2018-2020 Free Software Foundation, Inc.
+  Copyright (C) 2008-2015, 2018-2021 Free Software Foundation, Inc.
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
diff --git a/examples/c++/variant.test b/examples/c++/variant.test
index 9f77f832..c21bc426 100644
--- a/examples/c++/variant.test
+++ b/examples/c++/variant.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c++/variant.yy b/examples/c++/variant.yy
index 34527248..a470f83f 100644
--- a/examples/c++/variant.yy
+++ b/examples/c++/variant.yy
@@ -1,5 +1,5 @@
 /*
-  Copyright (C) 2008-2015, 2018-2020 Free Software Foundation, Inc.
+  Copyright (C) 2008-2015, 2018-2021 Free Software Foundation, Inc.
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
diff --git a/examples/c/README.md b/examples/c/README.md
index aa7461f8..8b52099b 100644
--- a/examples/c/README.md
+++ b/examples/c/README.md
@@ -81,7 +81,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 This file is part of GNU bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/bistromathic/README.md b/examples/c/bistromathic/README.md
index 5147cea4..cab5b31b 100644
--- a/examples/c/bistromathic/README.md
+++ b/examples/c/bistromathic/README.md
@@ -32,7 +32,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2020 Free Software Foundation, Inc.
+Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/bistromathic/bistromathic.test b/examples/c/bistromathic/bistromathic.test
index 1a2148da..6aa848ae 100755
--- a/examples/c/bistromathic/bistromathic.test
+++ b/examples/c/bistromathic/bistromathic.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2020 Free Software Foundation, Inc.
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/bistromathic/local.mk b/examples/c/bistromathic/local.mk
index e9801ab2..af3bd63a 100644
--- a/examples/c/bistromathic/local.mk
+++ b/examples/c/bistromathic/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2020 Free Software Foundation, Inc.
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/bistromathic/parse.y b/examples/c/bistromathic/parse.y
index 718ec904..2287004c 100644
--- a/examples/c/bistromathic/parse.y
+++ b/examples/c/bistromathic/parse.y
@@ -1,6 +1,6 @@
 /* Parser and scanner for bistromathic.   -*- C -*-
 
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/calc/README.md b/examples/c/calc/README.md
index e994826f..7cb5282d 100644
--- a/examples/c/calc/README.md
+++ b/examples/c/calc/README.md
@@ -9,7 +9,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2019-2020 Free Software Foundation, Inc.
+Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/calc/calc.test b/examples/c/calc/calc.test
index d778cf75..e4b4a0ce 100644
--- a/examples/c/calc/calc.test
+++ b/examples/c/calc/calc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2019-2020 Free Software Foundation, Inc.
+# Copyright (C) 2019-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/calc/local.mk b/examples/c/calc/local.mk
index 503b034a..b9a67e8c 100644
--- a/examples/c/calc/local.mk
+++ b/examples/c/calc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2019-2020 Free Software Foundation, Inc.
+## Copyright (C) 2019-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/lexcalc/README.md b/examples/c/lexcalc/README.md
index e0eddedf..2636a21d 100644
--- a/examples/c/lexcalc/README.md
+++ b/examples/c/lexcalc/README.md
@@ -11,7 +11,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/lexcalc/lexcalc.test b/examples/c/lexcalc/lexcalc.test
index 48a51575..6ecc4005 100644
--- a/examples/c/lexcalc/lexcalc.test
+++ b/examples/c/lexcalc/lexcalc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/lexcalc/local.mk b/examples/c/lexcalc/local.mk
index 636275c8..af9136ea 100644
--- a/examples/c/lexcalc/local.mk
+++ b/examples/c/lexcalc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/lexcalc/parse.y b/examples/c/lexcalc/parse.y
index d06a2036..7b266799 100644
--- a/examples/c/lexcalc/parse.y
+++ b/examples/c/lexcalc/parse.y
@@ -1,6 +1,6 @@
 /* Parser for lexcalc.   -*- C -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/lexcalc/scan.l b/examples/c/lexcalc/scan.l
index 3d71a381..961cd49c 100644
--- a/examples/c/lexcalc/scan.l
+++ b/examples/c/lexcalc/scan.l
@@ -1,6 +1,6 @@
 /* Scanner for lexcalc.   -*- C -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/local.mk b/examples/c/local.mk
index 860d6994..a7a1edf8 100644
--- a/examples/c/local.mk
+++ b/examples/c/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/mfcalc/local.mk b/examples/c/mfcalc/local.mk
index 69c91f71..639e9237 100644
--- a/examples/c/mfcalc/local.mk
+++ b/examples/c/mfcalc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2005-2006, 2008-2015, 2018-2020 Free Software
+## Copyright (C) 2005-2006, 2008-2015, 2018-2021 Free Software
 ## Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
diff --git a/examples/c/mfcalc/mfcalc.test b/examples/c/mfcalc/mfcalc.test
index 2e759ee5..5f599cb0 100755
--- a/examples/c/mfcalc/mfcalc.test
+++ b/examples/c/mfcalc/mfcalc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2005-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/pushcalc/README.md b/examples/c/pushcalc/README.md
index 4cf6ea7c..8ec1a3a7 100644
--- a/examples/c/pushcalc/README.md
+++ b/examples/c/pushcalc/README.md
@@ -20,7 +20,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2020 Free Software Foundation, Inc.
+Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/c/pushcalc/calc.test b/examples/c/pushcalc/calc.test
index 2241e104..d63761b7 100644
--- a/examples/c/pushcalc/calc.test
+++ b/examples/c/pushcalc/calc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2020 Free Software Foundation, Inc.
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/pushcalc/calc.y b/examples/c/pushcalc/calc.y
index 03ae04c4..08da2841 100644
--- a/examples/c/pushcalc/calc.y
+++ b/examples/c/pushcalc/calc.y
@@ -1,6 +1,6 @@
 /* Parser and scanner for pushcalc.   -*- C -*-
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/pushcalc/local.mk b/examples/c/pushcalc/local.mk
index 7f53a0c1..b02e6dc6 100644
--- a/examples/c/pushcalc/local.mk
+++ b/examples/c/pushcalc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2020 Free Software Foundation, Inc.
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/reccalc/README.md b/examples/c/reccalc/README.md
index 3bfab9e8..b89911af 100644
--- a/examples/c/reccalc/README.md
+++ b/examples/c/reccalc/README.md
@@ -26,7 +26,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/c/reccalc/local.mk b/examples/c/reccalc/local.mk
index 41a12828..03511cb4 100644
--- a/examples/c/reccalc/local.mk
+++ b/examples/c/reccalc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2019-2020 Free Software Foundation, Inc.
+## Copyright (C) 2019-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/c/reccalc/parse.y b/examples/c/reccalc/parse.y
index 3d3fbf4d..dc3e6c49 100644
--- a/examples/c/reccalc/parse.y
+++ b/examples/c/reccalc/parse.y
@@ -1,6 +1,6 @@
 /* Parser for reccalc.   -*- C -*-
 
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/reccalc/reccalc.test b/examples/c/reccalc/reccalc.test
index 124de6bc..ac3bc6d2 100644
--- a/examples/c/reccalc/reccalc.test
+++ b/examples/c/reccalc/reccalc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/c/reccalc/scan.l b/examples/c/reccalc/scan.l
index 1bf9773e..1775c8ff 100644
--- a/examples/c/reccalc/scan.l
+++ b/examples/c/reccalc/scan.l
@@ -1,6 +1,6 @@
 /* Scanner for reccalc.   -*- C -*-
 
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/c/rpcalc/local.mk b/examples/c/rpcalc/local.mk
index 0c3bfd8a..0e36c52e 100644
--- a/examples/c/rpcalc/local.mk
+++ b/examples/c/rpcalc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2005-2006, 2008-2015, 2018-2020 Free Software
+## Copyright (C) 2005-2006, 2008-2015, 2018-2021 Free Software
 ## Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
diff --git a/examples/c/rpcalc/rpcalc.test b/examples/c/rpcalc/rpcalc.test
index ef2fcfcf..f4905c40 100755
--- a/examples/c/rpcalc/rpcalc.test
+++ b/examples/c/rpcalc/rpcalc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2005-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/d/README.md b/examples/d/README.md
index fe05ef27..4c534544 100644
--- a/examples/d/README.md
+++ b/examples/d/README.md
@@ -15,7 +15,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/d/calc.test b/examples/d/calc.test
index cf4f80a8..5eb7fcb4 100644
--- a/examples/d/calc.test
+++ b/examples/d/calc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/d/calc.y b/examples/d/calc.y
index b0dee929..3ca8d193 100644
--- a/examples/d/calc.y
+++ b/examples/d/calc.y
@@ -1,6 +1,6 @@
 /* Parser and scanner for calc in D.   -*- D -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/d/local.mk b/examples/d/local.mk
index 4497e5a3..7d69a199 100644
--- a/examples/d/local.mk
+++ b/examples/d/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/extexi b/examples/extexi
index 948a9234..d9156ea5 100755
--- a/examples/extexi
+++ b/examples/extexi
@@ -3,7 +3,7 @@
 
 # This file is part of GNU Bison
 
-# Copyright (C) 1992, 2000-2001, 2005-2006, 2009-2015, 2018-2020 Free
+# Copyright (C) 1992, 2000-2001, 2005-2006, 2009-2015, 2018-2021 Free
 # Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
diff --git a/examples/java/README.md b/examples/java/README.md
index 25b7f27c..57b4a6ba 100644
--- a/examples/java/README.md
+++ b/examples/java/README.md
@@ -19,7 +19,7 @@ fill-column: 76
 ispell-dictionary: "american"
 End:
 
-Copyright (C) 2018-2020 Free Software Foundation, Inc.
+Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
diff --git a/examples/java/calc/Calc.test b/examples/java/calc/Calc.test
index c4143b29..14bea809 100644
--- a/examples/java/calc/Calc.test
+++ b/examples/java/calc/Calc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/java/calc/Calc.y b/examples/java/calc/Calc.y
index 1caa48b7..ecd47a26 100644
--- a/examples/java/calc/Calc.y
+++ b/examples/java/calc/Calc.y
@@ -1,6 +1,6 @@
 /* Parser and scanner for calc in Java.   -*- Java -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/java/calc/local.mk b/examples/java/calc/local.mk
index ba370ee5..38b60e2d 100644
--- a/examples/java/calc/local.mk
+++ b/examples/java/calc/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/java/local.mk b/examples/java/local.mk
index 447ae528..077498a0 100644
--- a/examples/java/local.mk
+++ b/examples/java/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2020 Free Software Foundation, Inc.
+## Copyright (C) 2020-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/java/simple/Calc.test b/examples/java/simple/Calc.test
index 70494124..3e3bd5b9 100644
--- a/examples/java/simple/Calc.test
+++ b/examples/java/simple/Calc.test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/examples/java/simple/Calc.y b/examples/java/simple/Calc.y
index 958bcd5e..045c66a1 100644
--- a/examples/java/simple/Calc.y
+++ b/examples/java/simple/Calc.y
@@ -1,6 +1,6 @@
 /* Simple parser and scanner in Java.   -*- Java -*-
 
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/examples/java/simple/local.mk b/examples/java/simple/local.mk
index 8a167d8d..76faa836 100644
--- a/examples/java/simple/local.mk
+++ b/examples/java/simple/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/examples/local.mk b/examples/local.mk
index 51c2c5a2..09e1747b 100644
--- a/examples/local.mk
+++ b/examples/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2005, 2008-2015, 2018-2020 Free Software Foundation,
+## Copyright (C) 2005, 2008-2015, 2018-2021 Free Software Foundation,
 ## Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
diff --git a/examples/test b/examples/test
index 7590e128..20f54d07 100755
--- a/examples/test
+++ b/examples/test
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# Copyright (C) 2005-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2005-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/lib/get-errno.c b/lib/get-errno.c
index ef3b71b4..1db3800e 100644
--- a/lib/get-errno.c
+++ b/lib/get-errno.c
@@ -1,6 +1,6 @@
 /* get-errno.c - get and set errno.
 
-   Copyright (C) 2002, 2006, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2006, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/lib/get-errno.h b/lib/get-errno.h
index b6550852..af761764 100644
--- a/lib/get-errno.h
+++ b/lib/get-errno.h
@@ -1,6 +1,6 @@
 /* get-errno.h - get and set errno.
 
-   Copyright (C) 2002, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2002, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/lib/local.mk b/lib/local.mk
index 9e634786..db0b9489 100644
--- a/lib/local.mk
+++ b/lib/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/lib/main.c b/lib/main.c
index 4a3015fe..84f84ca0 100644
--- a/lib/main.c
+++ b/lib/main.c
@@ -1,6 +1,6 @@
 /* Yacc library main function.
 
-   Copyright (C) 2002, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2002, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/lib/path-join.c b/lib/path-join.c
index 411f3316..32e7f002 100644
--- a/lib/path-join.c
+++ b/lib/path-join.c
@@ -1,5 +1,5 @@
 /* Concatenate path components.
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
diff --git a/lib/path-join.h b/lib/path-join.h
index c4444a47..18b6190f 100644
--- a/lib/path-join.h
+++ b/lib/path-join.h
@@ -1,5 +1,5 @@
 /* Concatenate path components.
-   Copyright (C) 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
diff --git a/lib/timevar.def b/lib/timevar.def
index 6e0d6ff0..baf76ecc 100644
--- a/lib/timevar.def
+++ b/lib/timevar.def
@@ -1,7 +1,7 @@
 /* This file contains the definitions for timing variables used to -*- C -*-
    measure run-time performance of the compiler.
 
-   Copyright (C) 2002, 2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    Contributed by Akim Demaille <akim@freefriends.org>.
diff --git a/lib/yyerror.c b/lib/yyerror.c
index 1277ee21..fe25d1fc 100644
--- a/lib/yyerror.c
+++ b/lib/yyerror.c
@@ -1,6 +1,6 @@
 /* Yacc library error-printing function.
 
-   Copyright (C) 2002, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2002, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/m4/bison-check-compiler-flag.m4 b/m4/bison-check-compiler-flag.m4
index d71543ac..fc30a290 100644
--- a/m4/bison-check-compiler-flag.m4
+++ b/m4/bison-check-compiler-flag.m4
@@ -2,7 +2,7 @@
 
 # serial 1
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
diff --git a/m4/bison-cxx-std.m4 b/m4/bison-cxx-std.m4
index 19f52f23..6f6717ae 100644
--- a/m4/bison-cxx-std.m4
+++ b/m4/bison-cxx-std.m4
@@ -1,6 +1,6 @@
 # bison-cxx-std.m4 serial 1
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
diff --git a/m4/bison-i18n.m4 b/m4/bison-i18n.m4
index a531df85..59ab5c47 100644
--- a/m4/bison-i18n.m4
+++ b/m4/bison-i18n.m4
@@ -1,6 +1,6 @@
 # bison-i18n.m4 serial 2
 
-dnl Copyright (C) 2005-2006, 2009-2015, 2018-2020 Free Software
+dnl Copyright (C) 2005-2006, 2009-2015, 2018-2021 Free Software
 dnl Foundation, Inc.
 
 dnl This file is free software; the Free Software Foundation
diff --git a/m4/c-working.m4 b/m4/c-working.m4
index 97f06dcd..81b479a1 100644
--- a/m4/c-working.m4
+++ b/m4/c-working.m4
@@ -1,6 +1,6 @@
 # Sanity test a C compiler.
 
-# Copyright (C) 2006, 2009-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2006, 2009-2015, 2018-2021 Free Software Foundation,
 # Inc.
 #
 # This program is free software: you can redistribute it and/or modify
diff --git a/m4/cxx.m4 b/m4/cxx.m4
index c7dd0f90..d7c046fe 100644
--- a/m4/cxx.m4
+++ b/m4/cxx.m4
@@ -1,7 +1,7 @@
 # -*- Autoconf -*-
 # Sanity-test a C++ compiler.
 #
-# Copyright (C) 2004, 2006, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2004, 2006, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
diff --git a/m4/flex.m4 b/m4/flex.m4
index 911a689e..914989cc 100644
--- a/m4/flex.m4
+++ b/m4/flex.m4
@@ -1,5 +1,5 @@
 # flex.m4 serial 2
-# Copyright (C) 2012-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2012-2015, 2018-2021 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
diff --git a/src/AnnotationList.c b/src/AnnotationList.c
index 92b6690f..ab46551e 100644
--- a/src/AnnotationList.c
+++ b/src/AnnotationList.c
@@ -1,6 +1,6 @@
 /* IELR's inadequacy annotation list.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/AnnotationList.h b/src/AnnotationList.h
index a9f808c5..539e1990 100644
--- a/src/AnnotationList.h
+++ b/src/AnnotationList.h
@@ -1,6 +1,6 @@
 /* IELR's inadequacy annotation list.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/InadequacyList.c b/src/InadequacyList.c
index 6d7f1922..d9ae9a3e 100644
--- a/src/InadequacyList.c
+++ b/src/InadequacyList.c
@@ -1,6 +1,6 @@
 /* IELR's inadequacy list.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/InadequacyList.h b/src/InadequacyList.h
index 317d9d5a..29866198 100644
--- a/src/InadequacyList.h
+++ b/src/InadequacyList.h
@@ -1,6 +1,6 @@
 /* IELR's inadequacy list.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/Sbitset.c b/src/Sbitset.c
index 3b165103..03d74836 100644
--- a/src/Sbitset.c
+++ b/src/Sbitset.c
@@ -1,6 +1,6 @@
 /* A simple, memory-efficient bitset implementation.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/Sbitset.h b/src/Sbitset.h
index c54def4e..6814ba8f 100644
--- a/src/Sbitset.h
+++ b/src/Sbitset.h
@@ -1,6 +1,6 @@
 /* A simple, memory-efficient bitset implementation.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/assoc.c b/src/assoc.c
index 0c3de26f..7337c0a3 100644
--- a/src/assoc.c
+++ b/src/assoc.c
@@ -1,6 +1,6 @@
 /* Associativity information.
 
-   Copyright (C) 2002, 2005-2006, 2008-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2005-2006, 2008-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/assoc.h b/src/assoc.h
index 9fdbb466..1b4b7f31 100644
--- a/src/assoc.h
+++ b/src/assoc.h
@@ -1,6 +1,6 @@
 /* Associativity information.
 
-   Copyright (C) 2002, 2006, 2008-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2006, 2008-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/closure.c b/src/closure.c
index 1ea77ee6..a85d5e44 100644
--- a/src/closure.c
+++ b/src/closure.c
@@ -1,7 +1,7 @@
 /* Closures for Bison
 
    Copyright (C) 1984, 1989, 2000-2002, 2004-2005, 2007, 2009-2015,
-   2018-2020 Free Software Foundation, Inc.
+   2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/closure.h b/src/closure.h
index 8fa1ed60..2d426ae5 100644
--- a/src/closure.h
+++ b/src/closure.h
@@ -1,6 +1,6 @@
 /* Subroutines for bison
 
-   Copyright (C) 1984, 1989, 2000-2002, 2007, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2002, 2007, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/complain.c b/src/complain.c
index b17b8e60..6a0723d4 100644
--- a/src/complain.c
+++ b/src/complain.c
@@ -1,6 +1,6 @@
 /* Declaration for error-reporting function for Bison.
 
-   Copyright (C) 2000-2002, 2004-2006, 2009-2015, 2018-2020 Free
+   Copyright (C) 2000-2002, 2004-2006, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/src/complain.h b/src/complain.h
index 303d0a54..9be0d052 100644
--- a/src/complain.h
+++ b/src/complain.h
@@ -1,6 +1,6 @@
 /* Declaration for error-reporting function for Bison.
 
-   Copyright (C) 2000-2002, 2006, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2000-2002, 2006, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/src/conflicts.c b/src/conflicts.c
index b7280be7..729a5ddd 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -1,6 +1,6 @@
 /* Find and resolve or report lookahead conflicts for bison,
 
-   Copyright (C) 1984, 1989, 1992, 2000-2015, 2018-2020 Free Software
+   Copyright (C) 1984, 1989, 1992, 2000-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/conflicts.h b/src/conflicts.h
index d4e679f0..40b843cc 100644
--- a/src/conflicts.h
+++ b/src/conflicts.h
@@ -1,6 +1,6 @@
 /* Find and resolve or report lookahead conflicts for bison,
 
-   Copyright (C) 2000-2002, 2004, 2007, 2009-2015, 2018-2020 Free
+   Copyright (C) 2000-2002, 2004, 2007, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/counterexample.c b/src/counterexample.c
index b4caef7d..2ad2430f 100644
--- a/src/counterexample.c
+++ b/src/counterexample.c
@@ -1,6 +1,6 @@
 /* Conflict counterexample generation
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/counterexample.h b/src/counterexample.h
index 735828fa..bf8b5573 100644
--- a/src/counterexample.h
+++ b/src/counterexample.h
@@ -1,6 +1,6 @@
 /* Conflict counterexample generation
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/derivation.c b/src/derivation.c
index f1b37639..4ce52fc7 100644
--- a/src/derivation.c
+++ b/src/derivation.c
@@ -1,6 +1,6 @@
 /* Counterexample derivation trees
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/derivation.h b/src/derivation.h
index 4dfba945..4759c4ca 100644
--- a/src/derivation.h
+++ b/src/derivation.h
@@ -1,6 +1,6 @@
 /* Counterexample derivation trees
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/derives.c b/src/derives.c
index f0d334c7..9411f35b 100644
--- a/src/derives.c
+++ b/src/derives.c
@@ -1,6 +1,6 @@
 /* Match rules with nonterminals for bison,
 
-   Copyright (C) 1984, 1989, 2000-2003, 2005, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2003, 2005, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/derives.h b/src/derives.h
index 33430e6f..8df5419d 100644
--- a/src/derives.h
+++ b/src/derives.h
@@ -1,6 +1,6 @@
 /* Match rules with nonterminals for bison,
 
-   Copyright (C) 1984, 1989, 2000-2002, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2002, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/files.c b/src/files.c
index 1f72730d..8e771f5a 100644
--- a/src/files.c
+++ b/src/files.c
@@ -1,6 +1,6 @@
 /* Open and close files for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/files.h b/src/files.h
index 22d1d750..09dd6765 100644
--- a/src/files.h
+++ b/src/files.h
@@ -1,6 +1,6 @@
 /* File names and variables for bison,
 
-   Copyright (C) 1984, 1989, 2000-2002, 2006-2007, 2009-2015, 2018-2020
+   Copyright (C) 1984, 1989, 2000-2002, 2006-2007, 2009-2015, 2018-2021
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/fixits.c b/src/fixits.c
index 701d2ad4..610fcb65 100644
--- a/src/fixits.c
+++ b/src/fixits.c
@@ -1,6 +1,6 @@
 /* Support for fixing grammar files.
 
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/fixits.h b/src/fixits.h
index f79217a3..a4ac44c3 100644
--- a/src/fixits.h
+++ b/src/fixits.h
@@ -1,6 +1,6 @@
 /* Support for fixing grammar files.
 
-   Copyright (C) 2019-2020 Free Software Foundation, Inc.
+   Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
diff --git a/src/flex-scanner.h b/src/flex-scanner.h
index 2acc9146..08e6978e 100644
--- a/src/flex-scanner.h
+++ b/src/flex-scanner.h
@@ -1,6 +1,6 @@
 /* Common parts between scan-code.l, scan-gram.l, and scan-skel.l.
 
-   Copyright (C) 2006, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2006, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/getargs.c b/src/getargs.c
index a15c07b5..2e93a395 100644
--- a/src/getargs.c
+++ b/src/getargs.c
@@ -1,6 +1,6 @@
 /* Parse command line arguments for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/getargs.h b/src/getargs.h
index 53826687..2c21f93f 100644
--- a/src/getargs.h
+++ b/src/getargs.h
@@ -1,6 +1,6 @@
 /* Parse command line arguments for bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/glyphs.c b/src/glyphs.c
index dcd7f0c7..898781af 100644
--- a/src/glyphs.c
+++ b/src/glyphs.c
@@ -1,6 +1,6 @@
 /* Graphical symbols.
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/glyphs.h b/src/glyphs.h
index 0af7e23c..ceee68f1 100644
--- a/src/glyphs.h
+++ b/src/glyphs.h
@@ -1,6 +1,6 @@
 /* Graphical symbols.
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/gram.c b/src/gram.c
index cc5e54b5..f011ec81 100644
--- a/src/gram.c
+++ b/src/gram.c
@@ -1,6 +1,6 @@
 /* Allocate input grammar variables for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 2001-2003, 2005-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 2001-2003, 2005-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/gram.h b/src/gram.h
index c6ce4194..eb5c2904 100644
--- a/src/gram.h
+++ b/src/gram.h
@@ -1,6 +1,6 @@
 /* Data definitions for internal representation of Bison's input.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2001-2007, 2009-2015, 2018-2020
+   Copyright (C) 1984, 1986, 1989, 1992, 2001-2007, 2009-2015, 2018-2021
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/graphviz.c b/src/graphviz.c
index e75bbb19..4c0239c0 100644
--- a/src/graphviz.c
+++ b/src/graphviz.c
@@ -1,6 +1,6 @@
 /* Output Graphviz specification of a state machine generated by Bison.
 
-   Copyright (C) 2006-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/graphviz.h b/src/graphviz.h
index ead22ffd..efad8471 100644
--- a/src/graphviz.h
+++ b/src/graphviz.h
@@ -1,6 +1,6 @@
 /* Output Graphviz specification of a state machine generated by Bison.
 
-   Copyright (C) 2006, 2010-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2006, 2010-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/ielr.c b/src/ielr.c
index 93fe3ac2..76d46a5d 100644
--- a/src/ielr.c
+++ b/src/ielr.c
@@ -1,6 +1,6 @@
 /* IELR main implementation.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/ielr.h b/src/ielr.h
index bb62625a..9b3cf470 100644
--- a/src/ielr.h
+++ b/src/ielr.h
@@ -1,6 +1,6 @@
 /* IELR main implementation.
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/lalr.c b/src/lalr.c
index 0f5d7147..43ea0be5 100644
--- a/src/lalr.c
+++ b/src/lalr.c
@@ -1,6 +1,6 @@
 /* Compute lookahead criteria for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 2000-2015, 2018-2020 Free Software
+   Copyright (C) 1984, 1986, 1989, 2000-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/lalr.h b/src/lalr.h
index f94123a4..1f743d45 100644
--- a/src/lalr.h
+++ b/src/lalr.h
@@ -1,7 +1,7 @@
 /* Compute lookahead criteria for bison,
 
    Copyright (C) 1984, 1986, 1989, 2000, 2002, 2004, 2006-2007,
-   2009-2015, 2018-2020 Free Software Foundation, Inc.
+   2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/local.mk b/src/local.mk
index 08ff62be..11e8d458 100644
--- a/src/local.mk
+++ b/src/local.mk
@@ -1,4 +1,4 @@
-## Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/src/location.c b/src/location.c
index 418a728d..7d96cc86 100644
--- a/src/location.c
+++ b/src/location.c
@@ -1,6 +1,6 @@
 /* Locations for Bison
 
-   Copyright (C) 2002, 2005-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2002, 2005-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/location.h b/src/location.h
index d351cb0e..65c75f00 100644
--- a/src/location.h
+++ b/src/location.h
@@ -1,6 +1,6 @@
 /* Locations for Bison
 
-   Copyright (C) 2002, 2004-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2002, 2004-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/lr0.c b/src/lr0.c
index fc3d0f4d..5d6f8470 100644
--- a/src/lr0.c
+++ b/src/lr0.c
@@ -1,6 +1,6 @@
 /* Generate the LR(0) parser states for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 2000-2002, 2004-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 2000-2002, 2004-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/lr0.h b/src/lr0.h
index 31366dbd..0daf7f71 100644
--- a/src/lr0.h
+++ b/src/lr0.h
@@ -1,6 +1,6 @@
 /* Generate the LR(0) parser states for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 2000-2002, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 2000-2002, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/lssi.c b/src/lssi.c
index 44dd819b..245461a9 100644
--- a/src/lssi.c
+++ b/src/lssi.c
@@ -1,6 +1,6 @@
 /* Lookahead sensitive state item searches for counterexample generation
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/lssi.h b/src/lssi.h
index 6aaf2bc4..cbb53f8d 100644
--- a/src/lssi.h
+++ b/src/lssi.h
@@ -1,6 +1,6 @@
 /* Lookahead sensitive state item searches for counterexample generation
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/main.c b/src/main.c
index 70954d5b..edc129e5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,7 +1,7 @@
 /* Top level entry point of Bison.
 
    Copyright (C) 1984, 1986, 1989, 1992, 1995, 2000-2002, 2004-2015,
-   2018-2020 Free Software Foundation, Inc.
+   2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/muscle-tab.c b/src/muscle-tab.c
index c0c66690..c2ba2ab6 100644
--- a/src/muscle-tab.c
+++ b/src/muscle-tab.c
@@ -1,6 +1,6 @@
 /* Muscle table manager for Bison.
 
-   Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/muscle-tab.h b/src/muscle-tab.h
index a0dd2020..30b50f9f 100644
--- a/src/muscle-tab.h
+++ b/src/muscle-tab.h
@@ -1,6 +1,6 @@
 /* Muscle table manager for Bison,
 
-   Copyright (C) 2001-2003, 2006-2015, 2018-2020 Free Software
+   Copyright (C) 2001-2003, 2006-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/named-ref.c b/src/named-ref.c
index 6e639ac2..7a81456e 100644
--- a/src/named-ref.c
+++ b/src/named-ref.c
@@ -1,6 +1,6 @@
 /* Named symbol references for Bison
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/named-ref.h b/src/named-ref.h
index 250c713f..6a838122 100644
--- a/src/named-ref.h
+++ b/src/named-ref.h
@@ -1,6 +1,6 @@
 /* Named symbol references for Bison
 
-   Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/nullable.c b/src/nullable.c
index d982987f..8661000b 100644
--- a/src/nullable.c
+++ b/src/nullable.c
@@ -1,6 +1,6 @@
 /* Calculate which nonterminals can expand into the null string for Bison.
 
-   Copyright (C) 1984, 1989, 2000-2006, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2006, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/nullable.h b/src/nullable.h
index 236c5054..4d02c759 100644
--- a/src/nullable.h
+++ b/src/nullable.h
@@ -1,6 +1,6 @@
 /* Part of the bison parser generator,
 
-   Copyright (C) 2000, 2002, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2000, 2002, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/output.c b/src/output.c
index 5c87d5b4..b34feb62 100644
--- a/src/output.c
+++ b/src/output.c
@@ -1,6 +1,6 @@
 /* Output the generated parsing program for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2020 Free
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/output.h b/src/output.h
index 64101306..45172f54 100644
--- a/src/output.h
+++ b/src/output.h
@@ -1,6 +1,6 @@
 /* Output the generated parsing program for bison,
 
-   Copyright (C) 2000-2003, 2006-2007, 2009-2015, 2018-2020 Free
+   Copyright (C) 2000-2003, 2006-2007, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/parse-gram.c b/src/parse-gram.c
index 5b1ac0a6..dd568627 100644
--- a/src/parse-gram.c
+++ b/src/parse-gram.c
@@ -2,7 +2,7 @@
 
 /* Bison implementation for Yacc-like parsers in C
 
-   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/src/parse-gram.h b/src/parse-gram.h
index 7dbd0ffd..1cd9c99c 100644
--- a/src/parse-gram.h
+++ b/src/parse-gram.h
@@ -2,7 +2,7 @@
 
 /* Bison interface for Yacc-like parsers in C
 
-   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 1984, 1989-1990, 2000-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/src/parse-gram.y b/src/parse-gram.y
index 2b24ac17..76773ff1 100644
--- a/src/parse-gram.y
+++ b/src/parse-gram.y
@@ -1,6 +1,6 @@
 /* Bison Grammar Parser                             -*- C -*-
 
-   Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/parse-simulation.c b/src/parse-simulation.c
index 70bfb177..93dbc03f 100644
--- a/src/parse-simulation.c
+++ b/src/parse-simulation.c
@@ -1,6 +1,6 @@
 /* Parser simulator for unifying counterexample search
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/parse-simulation.h b/src/parse-simulation.h
index 92eea21c..0331a321 100644
--- a/src/parse-simulation.h
+++ b/src/parse-simulation.h
@@ -1,6 +1,6 @@
 /* Parser simulator for unifying counterexample search
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/print-graph.c b/src/print-graph.c
index 48836f26..379093ad 100644
--- a/src/print-graph.c
+++ b/src/print-graph.c
@@ -1,6 +1,6 @@
 /* Output a graph of the generated parser, for Bison.
 
-   Copyright (C) 2001-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2001-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/print-graph.h b/src/print-graph.h
index c31a5ca2..78f83f15 100644
--- a/src/print-graph.h
+++ b/src/print-graph.h
@@ -1,6 +1,6 @@
 /* Output a graph of the generated parser, for Bison.
 
-   Copyright (C) 2000, 2006, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2000, 2006, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/print-xml.c b/src/print-xml.c
index c509089f..9d6fbd5f 100644
--- a/src/print-xml.c
+++ b/src/print-xml.c
@@ -1,6 +1,6 @@
 /* Print an xml on generated parser, for Bison,
 
-   Copyright (C) 2007, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2007, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/print-xml.h b/src/print-xml.h
index 51d3c15c..3ef0d57a 100644
--- a/src/print-xml.h
+++ b/src/print-xml.h
@@ -1,6 +1,6 @@
 /* Output an xml of the generated parser, for Bison.
 
-   Copyright (C) 2007, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2007, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/print.c b/src/print.c
index 7ef3ba4d..abd956dd 100644
--- a/src/print.c
+++ b/src/print.c
@@ -1,6 +1,6 @@
 /* Print information on generated parser, for bison,
 
-   Copyright (C) 1984, 1986, 1989, 2000-2005, 2007, 2009-2015, 2018-2020
+   Copyright (C) 1984, 1986, 1989, 2000-2005, 2007, 2009-2015, 2018-2021
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/print.h b/src/print.h
index 027abce4..b3c52542 100644
--- a/src/print.h
+++ b/src/print.h
@@ -1,6 +1,6 @@
 /* Print information on generated parser, for bison,
 
-   Copyright (C) 2000, 2009-2015, 2018-2020 Free Software Foundation,
+   Copyright (C) 2000, 2009-2015, 2018-2021 Free Software Foundation,
    Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/reader.c b/src/reader.c
index a43c5e41..2f8f33f5 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,7 +1,7 @@
 /* Input parser for Bison
 
    Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
-   2009-2015, 2018-2020 Free Software Foundation, Inc.
+   2009-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/reader.h b/src/reader.h
index 2fde52c6..72807b02 100644
--- a/src/reader.h
+++ b/src/reader.h
@@ -1,6 +1,6 @@
 /* Input parser for Bison
 
-   Copyright (C) 2000-2003, 2005-2007, 2009-2015, 2018-2020 Free
+   Copyright (C) 2000-2003, 2005-2007, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/reduce.c b/src/reduce.c
index 0061b687..b6130cce 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -1,6 +1,6 @@
 /* Grammar reduction for Bison.
 
-   Copyright (C) 1988-1989, 2000-2003, 2005-2015, 2018-2020 Free
+   Copyright (C) 1988-1989, 2000-2003, 2005-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/reduce.h b/src/reduce.h
index 36110404..80b479c9 100644
--- a/src/reduce.h
+++ b/src/reduce.h
@@ -1,6 +1,6 @@
 /* Grammar reduction for Bison.
 
-   Copyright (C) 2000-2002, 2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2000-2002, 2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/relation.c b/src/relation.c
index e9c50086..23f1c1b7 100644
--- a/src/relation.c
+++ b/src/relation.c
@@ -1,6 +1,6 @@
 /* Binary relations.
 
-   Copyright (C) 2002, 2004-2005, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2004-2005, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/relation.h b/src/relation.h
index 14366393..55f7677d 100644
--- a/src/relation.h
+++ b/src/relation.h
@@ -1,6 +1,6 @@
 /* Binary relations.
 
-   Copyright (C) 2002, 2004, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2004, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/scan-code.h b/src/scan-code.h
index 3859e2b2..da81b1e1 100644
--- a/src/scan-code.h
+++ b/src/scan-code.h
@@ -1,6 +1,6 @@
 /* Bison code properties structure and scanner.
 
-   Copyright (C) 2006-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/scan-code.l b/src/scan-code.l
index 86f87749..bfd0cf04 100644
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -1,6 +1,6 @@
 /* Bison Action Scanner                             -*- C -*-
 
-   Copyright (C) 2006-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2006-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/scan-gram.h b/src/scan-gram.h
index 4483fa81..a6655ab2 100644
--- a/src/scan-gram.h
+++ b/src/scan-gram.h
@@ -1,6 +1,6 @@
 /* Bison Grammar Scanner
 
-   Copyright (C) 2006-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2006-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/scan-gram.l b/src/scan-gram.l
index 6d33cdf2..302000d7 100644
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -1,6 +1,6 @@
 /* Bison Grammar Scanner                             -*- C -*-
 
-   Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/scan-skel.h b/src/scan-skel.h
index 5a6b5f3f..a138da29 100644
--- a/src/scan-skel.h
+++ b/src/scan-skel.h
@@ -1,6 +1,6 @@
 /* Scan Bison Skeletons.
 
-   Copyright (C) 2005-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2005-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/scan-skel.l b/src/scan-skel.l
index 4c524584..ce23d8c8 100644
--- a/src/scan-skel.l
+++ b/src/scan-skel.l
@@ -1,6 +1,6 @@
 /* Scan Bison Skeletons.                                       -*- C -*-
 
-   Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+   Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/state-item.c b/src/state-item.c
index 05cb8075..d8957c8e 100644
--- a/src/state-item.c
+++ b/src/state-item.c
@@ -1,6 +1,6 @@
 /* Counterexample Generation Search Nodes
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/state-item.h b/src/state-item.h
index a0a3d36f..ae046b30 100644
--- a/src/state-item.h
+++ b/src/state-item.h
@@ -1,6 +1,6 @@
 /* Counterexample Generation Search Nodes
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/state.c b/src/state.c
index 4a3d78aa..ed2520ad 100644
--- a/src/state.c
+++ b/src/state.c
@@ -1,6 +1,6 @@
 /* Type definitions for the finite state machine for Bison.
 
-   Copyright (C) 2001-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2001-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/state.h b/src/state.h
index 6a2fd1c3..7f8bda68 100644
--- a/src/state.h
+++ b/src/state.h
@@ -1,6 +1,6 @@
 /* Type definitions for the finite state machine for Bison.
 
-   Copyright (C) 1984, 1989, 2000-2004, 2007, 2009-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2004, 2007, 2009-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/strversion.c b/src/strversion.c
index 27c71d34..4b7d30bd 100644
--- a/src/strversion.c
+++ b/src/strversion.c
@@ -1,6 +1,6 @@
 /* Convert version string to int.
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/strversion.h b/src/strversion.h
index 6d8d6235..1793552e 100644
--- a/src/strversion.h
+++ b/src/strversion.h
@@ -1,6 +1,6 @@
 /* Convert version string to int.
 
-   Copyright (C) 2020 Free Software Foundation, Inc.
+   Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
diff --git a/src/symlist.c b/src/symlist.c
index 55c1fb6b..f72adf20 100644
--- a/src/symlist.c
+++ b/src/symlist.c
@@ -1,6 +1,6 @@
 /* Lists of symbols for Bison
 
-   Copyright (C) 2002, 2005-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2005-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/symlist.h b/src/symlist.h
index 39fdec40..e53bfa17 100644
--- a/src/symlist.h
+++ b/src/symlist.h
@@ -1,6 +1,6 @@
 /* Lists of symbols for Bison
 
-   Copyright (C) 2002, 2005-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2005-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/symtab.c b/src/symtab.c
index b5556715..3810b447 100644
--- a/src/symtab.c
+++ b/src/symtab.c
@@ -1,6 +1,6 @@
 /* Symbol table manager for Bison.
 
-   Copyright (C) 1984, 1989, 2000-2002, 2004-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 2000-2002, 2004-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/symtab.h b/src/symtab.h
index e85e5468..22bf0d39 100644
--- a/src/symtab.h
+++ b/src/symtab.h
@@ -1,6 +1,6 @@
 /* Definitions for symtab.c and callers, part of Bison.
 
-   Copyright (C) 1984, 1989, 1992, 2000-2002, 2004-2015, 2018-2020 Free
+   Copyright (C) 1984, 1989, 1992, 2000-2002, 2004-2015, 2018-2021 Free
    Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/system.h b/src/system.h
index fb65d573..4ebb51ad 100644
--- a/src/system.h
+++ b/src/system.h
@@ -1,6 +1,6 @@
 /* System-dependent definitions for Bison.
 
-   Copyright (C) 2000-2007, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2000-2007, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
diff --git a/src/tables.c b/src/tables.c
index d26a4a97..0c98c327 100644
--- a/src/tables.c
+++ b/src/tables.c
@@ -1,6 +1,6 @@
 /* Output the generated parsing program for Bison.
 
-   Copyright (C) 1984, 1986, 1989, 1992, 2000-2006, 2009-2015, 2018-2020
+   Copyright (C) 1984, 1986, 1989, 1992, 2000-2006, 2009-2015, 2018-2021
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/tables.h b/src/tables.h
index b0d420ad..7ba213b5 100644
--- a/src/tables.h
+++ b/src/tables.h
@@ -1,6 +1,6 @@
 /* Prepare the LALR and GLR parser tables.
 
-   Copyright (C) 2002, 2004, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002, 2004, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/uniqstr.c b/src/uniqstr.c
index a2b66cc6..462d0318 100644
--- a/src/uniqstr.c
+++ b/src/uniqstr.c
@@ -1,6 +1,6 @@
 /* Keep a unique copy of strings.
 
-   Copyright (C) 2002-2005, 2009-2015, 2018-2020 Free Software
+   Copyright (C) 2002-2005, 2009-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/src/uniqstr.h b/src/uniqstr.h
index 8f61ef4b..f9950ded 100644
--- a/src/uniqstr.h
+++ b/src/uniqstr.h
@@ -1,6 +1,6 @@
 /* Keeping a unique copy of strings.
 
-   Copyright (C) 2002-2003, 2008-2015, 2018-2020 Free Software
+   Copyright (C) 2002-2003, 2008-2015, 2018-2021 Free Software
    Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
diff --git a/tests/actions.at b/tests/actions.at
index da11ceb2..9039cc2d 100644
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -1,6 +1,6 @@
 # Executing Actions.                               -*- Autotest -*-
 
-# Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/atlocal.in b/tests/atlocal.in
index 23eb9ae2..2642de9f 100644
--- a/tests/atlocal.in
+++ b/tests/atlocal.in
@@ -1,7 +1,7 @@
 # @configure_input@                                     -*- shell-script -*-
 # Configurable variable values for Bison test suite.
 
-# Copyright (C) 2000-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2000-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/bison.in b/tests/bison.in
index f3b05b5b..e9f761e3 100644
--- a/tests/bison.in
+++ b/tests/bison.in
@@ -2,7 +2,7 @@
 # @configure_input@
 # Wrapper around a non installed bison to make it work as an installed one.
 
-# Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/c++.at b/tests/c++.at
index b894c0f7..c86621bf 100644
--- a/tests/c++.at
+++ b/tests/c++.at
@@ -1,6 +1,6 @@
 # Checking the C++ Features.                    -*- Autotest -*-
 
-# Copyright (C) 2004-2005, 2007-2015, 2018-2020 Free Software
+# Copyright (C) 2004-2005, 2007-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/calc.at b/tests/calc.at
index e24d6c83..cfc9f08f 100644
--- a/tests/calc.at
+++ b/tests/calc.at
@@ -1,6 +1,6 @@
 # Simple calculator.                         -*- Autotest -*-
 
-# Copyright (C) 2000-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2000-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/conflicts.at b/tests/conflicts.at
index befd017b..62f7535a 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -1,6 +1,6 @@
 # Exercising Bison on conflicts.                         -*- Autotest -*-
 
-# Copyright (C) 2002-2005, 2007-2015, 2018-2020 Free Software
+# Copyright (C) 2002-2005, 2007-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/counterexample.at b/tests/counterexample.at
index 4d1709a6..1553e8cb 100644
--- a/tests/counterexample.at
+++ b/tests/counterexample.at
@@ -1,6 +1,6 @@
 # Exercising Bison on counterexamples.                         -*- Autotest -*-
 
-# Copyright (C) 2020 Free Software Foundation, Inc.
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/cxx-type.at b/tests/cxx-type.at
index f1b6b144..5b6db0fa 100644
--- a/tests/cxx-type.at
+++ b/tests/cxx-type.at
@@ -1,6 +1,6 @@
 # Checking GLR Parsing.                         -*- Autotest -*-
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/diagnostics.at b/tests/diagnostics.at
index e8dcb384..5a000c34 100644
--- a/tests/diagnostics.at
+++ b/tests/diagnostics.at
@@ -1,6 +1,6 @@
 # Checking diagnostics.                              -*- Autotest -*-
 
-# Copyright (C) 2019-2020 Free Software Foundation, Inc.
+# Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/existing.at b/tests/existing.at
index 4700f9a8..d306c33d 100644
--- a/tests/existing.at
+++ b/tests/existing.at
@@ -1,6 +1,6 @@
 # Exercising Bison on actual grammars.                   -*- Autotest -*-
 
-# Copyright (C) 1989-1992, 2000-2005, 2007, 2009-2015, 2018-2020 Free
+# Copyright (C) 1989-1992, 2000-2005, 2007, 2009-2015, 2018-2021 Free
 # Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 51c6ee5e..d164e072 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -1,6 +1,6 @@
 # Checking GLR Parsing: Regression Tests           -*- Autotest -*-
 
-# Copyright (C) 2002-2003, 2005-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2002-2003, 2005-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/headers.at b/tests/headers.at
index 4e745ccb..ee5f457e 100644
--- a/tests/headers.at
+++ b/tests/headers.at
@@ -1,6 +1,6 @@
 # Bison Parser Headers.                               -*- Autotest -*-
 
-# Copyright (C) 2001-2002, 2006-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2001-2002, 2006-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/input.at b/tests/input.at
index cfa065ad..0be322ef 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -1,6 +1,6 @@
 # Checking the Bison reader.                    -*- Autotest -*-
 
-# Copyright (C) 2002-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2002-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/java.at b/tests/java.at
index 57472446..54fb50d5 100644
--- a/tests/java.at
+++ b/tests/java.at
@@ -1,6 +1,6 @@
 # Java tests for simple calculator.           -*- Autotest -*-
 
-# Copyright (C) 2007-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2007-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/javapush.at b/tests/javapush.at
index b3027c65..db49fbdc 100644
--- a/tests/javapush.at
+++ b/tests/javapush.at
@@ -1,6 +1,6 @@
 # Checking Java Push Parsing.                            -*- Autotest -*-
 
-# Copyright (C) 2013-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2013-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/linear b/tests/linear
index b12c972d..18a4f90a 100755
--- a/tests/linear
+++ b/tests/linear
@@ -3,7 +3,7 @@
 # Build a grammar whose LALR(1) parser has a given number of states.
 # Useful to test edge cases (e.g., 256 and 257 states, etc.).
 
-# Copyright (C) 2020 Free Software Foundation, Inc.
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/local.at b/tests/local.at
index c697f5a7..d8b003bf 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -2,7 +2,7 @@
 
 # Macros for the GNU Bison Test suite.
 
-# Copyright (C) 2003-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2003-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/local.mk b/tests/local.mk
index a14ba8fb..8c1c0bd7 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -1,6 +1,6 @@
 ## Makefile for Bison testsuite.
 
-## Copyright (C) 2000-2015, 2018-2020 Free Software Foundation, Inc.
+## Copyright (C) 2000-2015, 2018-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
diff --git a/tests/m4.at b/tests/m4.at
index 6a2ff83f..d6cb176d 100644
--- a/tests/m4.at
+++ b/tests/m4.at
@@ -1,6 +1,6 @@
 # Basic m4 macros.                               -*- Autotest -*-
 
-# Copyright (C) 2020 Free Software Foundation, Inc.
+# Copyright (C) 2020-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/named-refs.at b/tests/named-refs.at
index fb901ee5..111436c1 100644
--- a/tests/named-refs.at
+++ b/tests/named-refs.at
@@ -1,6 +1,6 @@
 # Named references test.                           -*- Autotest -*-
 
-# Copyright (C) 2009-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/output.at b/tests/output.at
index 5af1e914..8f405cb9 100644
--- a/tests/output.at
+++ b/tests/output.at
@@ -1,6 +1,6 @@
 # Checking the output filenames.                    -*- Autotest -*-
 
-# Copyright (C) 2000-2002, 2005-2015, 2018-2020 Free Software
+# Copyright (C) 2000-2002, 2005-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/push.at b/tests/push.at
index 16303777..960a4e3b 100644
--- a/tests/push.at
+++ b/tests/push.at
@@ -1,6 +1,6 @@
 # Checking Push Parsing.                            -*- Autotest -*-
 
-# Copyright (C) 2007, 2009-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2007, 2009-2015, 2018-2021 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/reduce.at b/tests/reduce.at
index b561100e..1f3934d1 100644
--- a/tests/reduce.at
+++ b/tests/reduce.at
@@ -1,6 +1,6 @@
 # Exercising Bison Grammar Reduction.                      -*- Autotest -*-
 
-# Copyright (C) 2001-2002, 2007-2015, 2018-2020 Free Software
+# Copyright (C) 2001-2002, 2007-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/regression.at b/tests/regression.at
index 20b5f739..ef7e7e93 100644
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -1,6 +1,6 @@
 # Bison Regressions.                               -*- Autotest -*-
 
-# Copyright (C) 2001-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2001-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/report.at b/tests/report.at
index 9021f6d5..889791b0 100644
--- a/tests/report.at
+++ b/tests/report.at
@@ -1,6 +1,6 @@
 # Bison Reports.                               -*- Autotest -*-
 
-# Copyright (C) 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/scanner.at b/tests/scanner.at
index 9ce13300..b74dbb99 100644
--- a/tests/scanner.at
+++ b/tests/scanner.at
@@ -1,6 +1,6 @@
 # Interface with the scanner.                           -*- Autotest -*-
 
-# Copyright (C) 2019-2020 Free Software Foundation, Inc.
+# Copyright (C) 2019-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/tests/sets.at b/tests/sets.at
index 4b06c111..05bad22a 100644
--- a/tests/sets.at
+++ b/tests/sets.at
@@ -1,6 +1,6 @@
 # Exercising Bison Grammar Sets.                      -*- Autotest -*-
 
-# Copyright (C) 2001-2002, 2005, 2007, 2009-2015, 2018-2020 Free
+# Copyright (C) 2001-2002, 2005, 2007, 2009-2015, 2018-2021 Free
 # Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/skeletons.at b/tests/skeletons.at
index 744e57b5..da81cf5d 100644
--- a/tests/skeletons.at
+++ b/tests/skeletons.at
@@ -1,6 +1,6 @@
 # Checking skeleton support.                     -*- Autotest -*-
 
-# Copyright (C) 2007, 2009-2015, 2018-2020 Free Software Foundation,
+# Copyright (C) 2007, 2009-2015, 2018-2021 Free Software Foundation,
 # Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/synclines.at b/tests/synclines.at
index 431af776..5ffaee3a 100644
--- a/tests/synclines.at
+++ b/tests/synclines.at
@@ -1,6 +1,6 @@
 # Executing Actions.                               -*- Autotest -*-
 
-# Copyright (C) 2002, 2004-2005, 2007, 2009-2015, 2018-2020 Free
+# Copyright (C) 2002, 2004-2005, 2007, 2009-2015, 2018-2021 Free
 # Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/testsuite.at b/tests/testsuite.at
index b09872dc..76ae47a5 100644
--- a/tests/testsuite.at
+++ b/tests/testsuite.at
@@ -1,6 +1,6 @@
 # Test suite for GNU Bison.                             -*- Autotest -*-
 
-# Copyright (C) 2000-2004, 2006-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2000-2004, 2006-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/torture.at b/tests/torture.at
index f41b8487..47fbc539 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -1,6 +1,6 @@
 # Torturing Bison.                                    -*- Autotest -*-
 
-# Copyright (C) 2001-2002, 2004-2007, 2009-2015, 2018-2020 Free Software
+# Copyright (C) 2001-2002, 2004-2007, 2009-2015, 2018-2021 Free Software
 # Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
diff --git a/tests/types.at b/tests/types.at
index d92c4a43..cb7c2327 100644
--- a/tests/types.at
+++ b/tests/types.at
@@ -1,6 +1,6 @@
 # Value type.                                     -*- Autotest -*-
 
-# Copyright (C) 2013-2015, 2018-2020 Free Software Foundation, Inc.
+# Copyright (C) 2013-2015, 2018-2021 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by

From 4109d56aa974627e7088964d5342a0788f6ede78 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 23 Jan 2021 10:06:17 +0100
Subject: [PATCH 22/26] news: update

---
 NEWS | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/NEWS b/NEWS
index e9715723..9ffed274 100644
--- a/NEWS
+++ b/NEWS
@@ -4,8 +4,17 @@ GNU Bison NEWS
 
 ** Bug fixes
 
+*** GLR parsers now support %merge together with api.value.type=union.
+
+*** C++ parsers use noexcept in more places.
+
+*** Generated parsers avoid some warnings about signedness issues.
+
+*** C-language parsers no avoid warnings from pedantic clang.
+
 *** C-language parsers now work around quirks of HP-UX 11.23 (2003).
 
+
 * Noteworthy changes in release 3.7.4 (2020-11-14) [stable]
 
 ** Bug fixes

From 236b85dd28b8873eb8f7e8827e485f3b0c6a12d1 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 23 Jan 2021 15:08:48 +0100
Subject: [PATCH 23/26] package: pacify syntax-check

* cfg.mk: Currently we cannot update gnulib because of portability
issues with ancient versions of clang
(https://lists.gnu.org/r/bug-gnulib/2021-01/msg00241.html).  So skip
the check about copyright date for gnulib.
---
 cfg.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cfg.mk b/cfg.mk
index 6725a186..84756ac5 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -156,6 +156,7 @@ exclude = \
 $(call exclude,                                                                 \
   bindtextdomain=^lib/main.c$$                                                  \
   cast_of_argument_to_free=^src/muscle-tab.c$$                                  \
+  copyright_check=gnulib/lib/version-etc.c$$                                    \
   error_message_uppercase=etc/bench.pl.in$$                                     \
   po_check=^tests|(^po/POTFILES.in|.md)$$                                       \
   preprocessor_indentation=^data/|^lib/|^src/parse-gram.[ch]$$                  \

From 2c294c132528ede23d8ae4959783a67e9ff05ac5 Mon Sep 17 00:00:00 2001
From: Vincent Imbimbo <vmi6@cornell.edu>
Date: Sat, 23 Jan 2021 13:25:18 -0500
Subject: [PATCH 24/26] cex: fix state-item pruning

There were several bugs in pruning that would leave the state-item
graph in an inconsistent state which could cause crashes later on:

- Pruning now happens in one pass instead of two.

- Disabled state-items no longer prune the state-items they transition
  to if that state-item has other states that transition to it.

- State-items that transition to disabled state-items are always
  pruned even if they have productions.

Reported by Michal Bartkowiak <michal.bartkowiak@nokia.com>
https://lists.gnu.org/r/bug-bison/2021-01/msg00000.html
and Zartaj Majeed
https://github.com/akimd/bison/issues/71

* src/state-item.c (prune_forward, prune_backward): Fuse into...
(prune_state_item): this.
Adjust callers.
---
 NEWS             |  4 ++++
 src/state-item.c | 59 ++++++++++++++++++------------------------------
 2 files changed, 26 insertions(+), 37 deletions(-)

diff --git a/NEWS b/NEWS
index 9ffed274..05d72dda 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,10 @@ GNU Bison NEWS
 
 ** Bug fixes
 
+*** Counterexample Generation
+
+  In some cases counterexample generation could crash.  This is fixed.
+
 *** GLR parsers now support %merge together with api.value.type=union.
 
 *** C++ parsers use noexcept in more places.
diff --git a/src/state-item.c b/src/state-item.c
index d8957c8e..a2e0f957 100644
--- a/src/state-item.c
+++ b/src/state-item.c
@@ -384,11 +384,10 @@ disable_state_item (state_item *si)
     bitset_free (si->prods);
 }
 
-/* disable all transitions and productions that can only be
- * reached through this state_item.
- */
+/* Disable all state_item paths that lead to/from SI and nowhere
+   else.  */
 static void
-prune_forward (const state_item *si)
+prune_state_item (const state_item *si)
 {
   state_item_list queue =
     gl_list_create (GL_LINKED_LIST, NULL, NULL, NULL, true, 1,
@@ -398,8 +397,16 @@ prune_forward (const state_item *si)
     {
       state_item *dsi = (state_item *) gl_list_get_at (queue, 0);
       gl_list_remove_at (queue, 0);
-      if (dsi->trans >= 0)
-        gl_list_add_last (queue, &state_items[dsi->trans]);
+      if (SI_DISABLED (dsi - state_items))
+        continue;
+
+      if (dsi->trans >= 0 && !SI_DISABLED (dsi->trans))
+      {
+        const state_item *trans = &state_items[dsi->trans];
+        bitset_reset (trans->revs, dsi - state_items);
+        if (bitset_empty_p (trans->revs))
+          gl_list_add_last (queue, trans);
+      }
 
       if (dsi->prods)
         {
@@ -407,32 +414,15 @@ prune_forward (const state_item *si)
           state_item_number sin;
           BITSET_FOR_EACH (biter, dsi->prods, sin, 0)
             {
+              if (SI_DISABLED (sin))
+                continue;
               const state_item *prod = &state_items[sin];
               bitset_reset (prod->revs, dsi - state_items);
               if (bitset_empty_p (prod->revs))
                 gl_list_add_last (queue, prod);
             }
         }
-      if (dsi != si)
-        disable_state_item (dsi);
-    }
-  gl_list_free (queue);
-}
 
-/* disable all state_item paths that lead to
- * si and nowhere else.
- */
-static void
-prune_backward (const state_item *si)
-{
-  state_item_list queue =
-    gl_list_create (GL_LINKED_LIST, NULL, NULL, NULL, true, 1,
-                    (const void **) &si);
-
-  while (gl_list_size (queue) > 0)
-    {
-      state_item *dsi = (state_item *) gl_list_get_at (queue, 0);
-      gl_list_remove_at (queue, 0);
       bitset_iterator biter;
       state_item_number sin;
       BITSET_FOR_EACH (biter, dsi->revs, sin, 0)
@@ -440,7 +430,9 @@ prune_backward (const state_item *si)
           if (SI_DISABLED (sin))
             continue;
           state_item *rev = &state_items[sin];
-          if (rev->prods)
+          if (&state_items[rev->trans] == dsi)
+            gl_list_add_last (queue, rev);
+          else if (rev->prods)
             {
               bitset_reset (rev->prods, dsi - state_items);
               if (bitset_empty_p (rev->prods))
@@ -449,16 +441,13 @@ prune_backward (const state_item *si)
           else
             gl_list_add_last (queue, rev);
         }
-      if (dsi != si)
-        disable_state_item (dsi);
+      disable_state_item (dsi);
     }
   gl_list_free (queue);
 }
 
-/*
- To make searches more efficient, we can prune away paths that are
- caused by disabled transitions.
- */
+/* To make searches more efficient, prune away paths that are caused
+   by disabled transitions.  */
 static void
 prune_disabled_paths (void)
 {
@@ -466,11 +455,7 @@ prune_disabled_paths (void)
     {
       state_item *si = &state_items[i];
       if (si->trans == -1 && item_number_is_symbol_number (*si->item))
-        {
-          prune_forward (si);
-          prune_backward (si);
-          disable_state_item (si);
-        }
+        prune_state_item (si);
     }
 }
 

From c22902e360e0fbbe9fd5657dcf107e03166da309 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sat, 23 Jan 2021 18:40:15 +0100
Subject: [PATCH 25/26] tables: fix handling for useless tokens
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In some rare conditions, the generated parser can be wrong when there
are useless tokens.

Reported by Balázs Scheidler.
https://github.com/akimd/bison/issues/72

Balázs managed to prove that the bug was introduced in

    commit af1c6f973a60a51c609903713ff8f7fce0887025
    Author: Theophile Ranquet <ranquet@lrde.epita.fr>
    Date:   Tue Nov 13 10:38:49 2012 +0000

    tables: use bitsets for a performance boost

    Suggested by Yuri at
    <http://lists.gnu.org/archive/html/bison-patches/2012-01/msg00000.html>.

    The improvement is marginal for most grammars, but notable for large
    grammars (e.g., PosgreSQL's postgre.y), and very large for the
    sample.y grammar submitted by Yuri in
    http://lists.gnu.org/archive/html/bison-patches/2012-01/msg00012.html.
    Measured with --trace=time -fsyntax-only.

    parser action tables    postgre.y     sample.y
    Before                 0,129 (44%)  37,095 (99%)
    After                  0,117 (42%)   5,046 (93%)

    * src/tables.c (pos): Replace this set of integer coded as an unsorted
    array of integers with...
    (pos_set): this bitset.

which was implemented long ago, but that I installed only recently
(March 2019), first published in v3.3.90.

That patch introduces a bitset to represent a set of integers.  It
managed negative integers by using a (fixed) base (the smallest
integer to represent).  It avoided negative accesses into the bitset
by ignoring integers smaller than the base, under the asumption that
these cases correspond to useless tokens that are ignored anyway.
While it turns out to be true for all the test cases in the test suite
(!), Balázs' use case demonstrates that it is not always the case.

So we need to be able to accept negative integers that are smaller
than the current base.

"Amusingly" enough, the aforementioned patch was visibly unsure about
itself:

    /* Store PLACE into POS_SET.  PLACE might not belong to the set
       of possible values for instance with useless tokens.  It
       would be more satisfying to eliminate the need for this
       'if'.  */

This commit needs several improvements in the future:
- support from bitset for bit assignment and shifts
- amortized resizing of pos_set
- test cases

* src/tables.c (pos_set_base, pos_set_dump, pos_set_set, pos_set_test):
New.
Use them instead of using bitset_set and bitset_test directly.
---
 NEWS         |  7 ++++-
 src/tables.c | 83 +++++++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 79 insertions(+), 11 deletions(-)

diff --git a/NEWS b/NEWS
index 05d72dda..720f2b1d 100644
--- a/NEWS
+++ b/NEWS
@@ -8,13 +8,18 @@ GNU Bison NEWS
 
   In some cases counterexample generation could crash.  This is fixed.
 
+*** Fix Table Generation
+
+  In some very rare conditions, when there are many useless tokens, it was
+  possible to generate incorrect parsers.
+
 *** GLR parsers now support %merge together with api.value.type=union.
 
 *** C++ parsers use noexcept in more places.
 
 *** Generated parsers avoid some warnings about signedness issues.
 
-*** C-language parsers no avoid warnings from pedantic clang.
+*** C-language parsers now avoid warnings from pedantic clang.
 
 *** C-language parsers now work around quirks of HP-UX 11.23 (2003).
 
diff --git a/src/tables.c b/src/tables.c
index 0c98c327..b04a496e 100644
--- a/src/tables.c
+++ b/src/tables.c
@@ -111,9 +111,13 @@ base_number *base = NULL;
    computation equals to BASE_MINIMUM, later mapped to BASE_NINF to
    keep parser tables small.  */
 base_number base_ninf = 0;
+
 /* Bitset representing an integer set in the range
-   -nstates..table_size (as an upper bound) */
+   POS_SET_OFFSET..(POS_SET_OFFSET + SIZE).  POS_SET_OFFSET is
+   nonpositive. */
 static bitset pos_set = NULL;
+/* The integer denoted by bitno 0 in pos_set.  */
+static int pos_set_base = 0;
 
 static int *conflrow;
 int *conflict_table;
@@ -138,6 +142,71 @@ int high;
 state_number *yydefgoto;
 rule_number *yydefact;
 
+
+/*----------.
+| pos_set.  |
+`----------*/
+
+#if 0
+static void
+pos_set_dump (void)
+{
+  fprintf (stderr, "pos_set (%ld, %d) =", bitset_size (pos_set), pos_set_base);
+  bitset_iterator biter;
+  int i;
+  BITSET_FOR_EACH (biter, pos_set, i, 0)
+    fprintf (stderr, " %d", i + pos_set_base);
+  putc ('\n', stderr);
+}
+#endif
+
+
+/* The size and base of POS_SET are not known, we need to be able to
+   move the base farther "on the left", and grow "on the right".
+
+   It would be nice to be able to predict the base accurately, but it
+   seems difficult (-nstates seems to work most of the time, except
+   when there are useless tokens).
+
+   FIXME: The current approach is correct, but with poor performances.
+   Bitsets need to support 'assign' and 'shift'.  And instead of
+   extending POS_SET just for the out-of-range new values, we need
+   something like doubling the size.
+  */
+
+static void
+pos_set_set (int pos)
+{
+  int bitno = pos - pos_set_base;
+  if (bitno < 0)
+    {
+      const int delta = pos_set_base - pos;
+      const int old_size = bitset_size (pos_set);
+      const int new_size = old_size + delta;
+      bitset_resize (pos_set, new_size);
+      // Shift all the bits by DELTA.
+      // FIXME: add bitset_assign, and bitset_shift?
+      for (int i = new_size - 1; delta <= i ; --i)
+        if (bitset_test (pos_set, i))
+          bitset_set (pos_set, i + delta);
+        else
+          bitset_reset (pos_set, i + delta);
+      pos_set_base = pos;
+      bitno = 0;
+    }
+  else if (bitset_size (pos_set) <= bitno)
+    bitset_resize (pos_set, bitno + 1);
+  bitset_set (pos_set, bitno);
+}
+
+static bool
+pos_set_test (int pos)
+{
+  const int bitno = pos - pos_set_base;
+  return bitset_test (pos_set, bitno);
+}
+
+
 /*-------------------------------------------------------------------.
 | If TABLE, CONFLICT_TABLE, and CHECK are too small to be addressed  |
 | at DESIRED, grow them.  TABLE[DESIRED] can be used, so the desired |
@@ -168,8 +237,6 @@ table_grow (int desired)
   check = xnrealloc (check, table_size, sizeof *check);
   for (int i = old_size; i < table_size; ++i)
     check[i] = -1;
-
-  bitset_resize (pos_set, table_size + nstates);
 }
 
 
@@ -672,7 +739,7 @@ pack_vector (vector_number vector)
               ok = false;
           }
 
-        if (ok && bitset_test (pos_set, nstates + res))
+        if (ok && pos_set_test (res))
           ok = false;
       }
 
@@ -732,6 +799,7 @@ pack_table (void)
 {
   base = xnmalloc (nvectors, sizeof *base);
   pos_set = bitset_create (table_size + nstates, BITSET_FRUGAL);
+  pos_set_base = -nstates;
   table = xcalloc (table_size, sizeof *table);
   conflict_table = xcalloc (table_size, sizeof *conflict_table);
   check = xnmalloc (table_size, sizeof *check);
@@ -757,12 +825,7 @@ pack_table (void)
         /* Action of I were already coded for S.  */
         place = base[s];
 
-      /* Store PLACE into POS_SET.  PLACE might not belong to the set
-         of possible values for instance with useless tokens.  It
-         would be more satisfying to eliminate the need for this
-         'if'.  */
-      if (0 <= nstates + place)
-        bitset_set (pos_set, nstates + place);
+      pos_set_set (place);
       base[order[i]] = place;
     }
 

From 2fac23b9ddf13bfc7ad8326ec112a4d138774565 Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sun, 24 Jan 2021 08:30:41 +0100
Subject: [PATCH 26/26] version 3.7.5

* NEWS: Record release date.
---
 NEWS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 720f2b1d..c92ba62a 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,6 @@
 GNU Bison NEWS
 
-* Noteworthy changes in release ?.? (????-??-??) [?]
+* Noteworthy changes in release 3.7.5 (2021-01-24) [stable]
 
 ** Bug fixes