version 3.3.2

* NEWS: Record release date.

.prev-version

@@ -1 +1 @@
-3.2.90
+3.3.1

.travis.yml

@@ -8,7 +8,8 @@ language: cpp
 env:
   global:
     # ICC serial number.
-    secure: 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
+    # See https://github.com/nemequ/icc-travis.
+    secure: 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
 
 matrix:
   include:

NEWS

@@ -1,6 +1,72 @@
 GNU Bison NEWS
 
-* Noteworthy changes in release 3.2.91 (2019-01-19) [beta]
+* Noteworthy changes in release 3.3.2 (2019-02-03) [stable]
+
+** Bug fixes
+
+  Bison 3.3 failed to generate parsers for grammars with unused nonterminal
+  symbols.
+
+* Noteworthy changes in release 3.3.1 (2019-01-27) [stable]
+
+** Changes
+
+  The option -y/--yacc used to imply -Werror=yacc, which turns uses of Bison
+  extensions into errors.  It now makes them simple warnings (-Wyacc).
+
+* Noteworthy changes in release 3.3 (2019-01-26) [stable]
+
+  A new mailing list was created, Bison Announce.  It is low traffic, and is
+  only about announcing new releases and important messages (e.g., polls
+  about major decisions to make).
+
+  https://lists.gnu.org/mailman/listinfo/bison-announce
+
+** Backward incompatible changes
+
+  Support for DJGPP, which has been unmaintained and untested for years, is
+  removed.
+
+** Deprecated features
+
+  A new feature, --update (see below) helps adjusting existing grammars to
+  deprecations.
+
+*** Deprecated directives
+
+  The %error-verbose directive is deprecated in favor of '%define
+  parse.error verbose' since Bison 3.0, but no warning was issued.
+
+  The '%name-prefix "xx"' directive is deprecated in favor of '%define
+  api.prefix {xx}' since Bison 3.0, but no warning was issued.  These
+  directives are slightly different, you might need to adjust your code.
+  %name-prefix renames only symbols with external linkage, while api.prefix
+  also renames types and macros, including YYDEBUG, YYTOKENTYPE,
+  yytokentype, YYSTYPE, YYLTYPE, etc.
+
+  Users of Flex that move from '%name-prefix "xx"' to '%define api.prefix
+  {xx}' will typically have to update YY_DECL from
+
+    #define YY_DECL int xxlex (YYSTYPE *yylval, YYLTYPE *yylloc)
+
+  to
+
+    #define YY_DECL int xxlex (XXSTYPE *yylval, XXLTYPE *yylloc)
+
+*** Deprecated %define variable names
+
+  The following variables, mostly related to parsers in Java, have been
+  renamed for consistency.  Backward compatibility is ensured, but upgrading
+  is recommended.
+
+    abstract           -> api.parser.abstract
+    annotations        -> api.parser.annotations
+    extends            -> api.parser.extends
+    final              -> api.parser.final
+    implements         -> api.parser.implements
+    parser_class_name  -> api.parser.class
+    public             -> api.parser.public
+    strictfp           -> api.parser.strictfp
 
 ** New features
 
@@ -56,62 +122,14 @@ GNU Bison NEWS
     %%
     exp:;
 
-* Noteworthy changes in release 3.2.90 (2019-01-12) [beta]
-
-** Backward incompatible changes
-
-  Support for DJGPP, which has been unmaintained and untested for years, is
-  removed.
-
-** Deprecated features
-
-*** Deprecated directives
-
-  The %error-verbose directive is deprecated in favor of '%define
-  parse.error verbose' since Bison 3.0, but no warning was issued.
-
-  The '%name-prefix "xx"' directive is deprecated in favor of '%define
-  api.prefix {xx}' since Bison 3.0, but no warning was issued.  These
-  directives are slightly different, you might need to adjust your code.
-  %name-prefix renames only symbols with external linkage, while api.prefix
-  also renames types and macros, including @code{YYDEBUG},
-  @code{YYTOKENTYPE}, @code{yytokentype}, @code{YYSTYPE}, @code{YYLTYPE},
-  etc.
-
-  Users of Flex that move from '%name-prefix "xx"' to '%define api.prefix
-  {xx}' will typically have to update YY_DECL from
-
-    #define YY_DECL int xxlex (YYSTYPE *yylval, YYLTYPE *yylloc)
-
-  to
-
-    #define YY_DECL int xxlex (XXSTYPE *yylval, XXLTYPE *yylloc)
-
-*** Deprecated %define variable names
-
-  The following variables, mostly related to parsers in Java, have been
-  renamed for consistency.  Backward compatibility is ensured, but upgrading
-  is recommended.
-
-    abstract           -> api.parser.abstract
-    annotations        -> api.parser.annotations
-    extends            -> api.parser.extends
-    final              -> api.parser.final
-    implements         -> api.parser.implements
-    parser_class_name  -> api.parser.class
-    public             -> api.parser.public
-    strictfp           -> api.parser.strictfp
-
-** New features
-
 *** Bison is now relocatable
 
   If you pass '--enable-relocatable' to 'configure', Bison is relocatable.
 
   A relocatable program can be moved or copied to a different location on
   the file system.  It can also be used through mount points for network
-  sharing.  It is possible to make symlinks to the installed and moved
-  programs, and invoke them through the symlink.
+  sharing.  It is possible to make symbolic links to the installed and moved
+  programs, and invoke them through the symbolic link.
 
 *** %expect and %expect-rr modifiers on individual rules
 
@@ -190,7 +208,7 @@ GNU Bison NEWS
 *** C++: Actual token constructors
 
   When variants and token constructors are enabled, in addition to the
-  type-safe named token constructors (make_ID, amke_INT, etc.), we now
+  type-safe named token constructors (make_ID, make_INT, etc.), we now
   generate genuine constructors for symbol_type.
 
   For instance with these declarations
@@ -205,17 +223,18 @@ GNU Bison NEWS
     symbol_type (int token, const int&);
     symbol_type (int token);
 
-  which should be used in a Flex-scanner as follows.
-
-    %%
-    [a-z]+   return yy::parser::symbol_type (ID, yytext);
-    [0-9]+   return yy::parser::symbol_type (INT, text_to_int (yytext);
-    ":"      return yy::parser::symbol_type (’:’);
-    <<EOF>>  return yy::parser::symbol_type (0);
-
   Correct matching between token types and value types is checked via
-  'assert'.  For instance, 'symbol_type (ID, 42)' would abort (while
-  'make_ID (42)' would not even compile).
+  'assert'; for instance, 'symbol_type (ID, 42)' would abort.  Named
+  constructors are preferable, as they offer better type safety (for
+  instance 'make_ID (42)' would not even compile), but symbol_type
+  constructors may help when token types are discovered at run-time, e.g.,
+
+     [a-z]+   {
+                if (auto i = lookup_keyword (yytext))
+                  return yy::parser::symbol_type (i);
+                else
+                  return yy::parser::make_ID (yytext);
+              }
 
 *** C++: Variadic emplace
 
@@ -307,7 +326,7 @@ GNU Bison NEWS
   where TAG denotes a type tag such as ‘<ival>’, ID denotes an identifier
   such as ‘NUM’, NUMBER a decimal or hexadecimal integer such as ‘300’ or
   ‘0x12d’, CHAR a character literal such as ‘'+'’, and STRING a string
-  literal such as ‘"number"’.  The postfix quantifiers are ‘?’ (zero or
+  literal such as ‘"number"’.  The post-fix quantifiers are ‘?’ (zero or
   one), ‘*’ (zero or more) and ‘+’ (one or more).
 
 * Noteworthy changes in release 3.2.4 (2018-12-24) [stable]
@@ -3464,10 +3483,14 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  LocalWords:  pragmas noreturn untyped Rozenman unexpanded Wojciech Polak
  LocalWords:  Alexandre MERCHANTABILITY yytype emplace ptr automove lvalues
  LocalWords:  nonterminal yy args Pragma dereference yyformat rhs docdir
- LocalWords:  Redeclarations rpcalc Autoconf YFLAGS Makefiles PROG
- LocalWords:  Heimbigner AST src ast Makefile srcdir MinGW
+ LocalWords:  Redeclarations rpcalc Autoconf YFLAGS Makefiles PROG DECL num
+ LocalWords:  Heimbigner AST src ast Makefile srcdir MinGW xxlex XXSTYPE
+ LocalWords:  XXLTYPE strictfp IDEs ffixit fdiagnostics parseable fixits
+ LocalWords:  Wdeprecated yytext Variadic variadic yyrhs yyphrs RCS README
+ LocalWords:  noexcept constexpr ispell american deprecations
 
 Local Variables:
+ispell-dictionary: "american"
 mode: outline
 fill-column: 76
 End:

THANKS

@@ -18,6 +18,7 @@ Antonio Silva Correia     [email protected]
 Arnold Robbins            [email protected]
 Art Haas                  [email protected]
 Askar Safin               [email protected]
+Balázs Scheidler          [email protected]
 Baron Schwartz            [email protected]
 Ben Pfaff                 [email protected]
 Benoit Perrot             [email protected]

TODO

@@ -1,5 +1,7 @@
 * Bison 3.4
 ** injection rules
+** glr.cc
+move glr.c into the yy namespace
 ** improve syntax errors (UTF-8, internationalization)
 Bison depends on the current locale.  For instance:
 

configure.ac

@@ -100,7 +100,7 @@ if test "$enable_gcc_warnings" = yes; then
     -Wpointer-arith -Wshadow
     -Wwrite-strings'
   warn_c='-Wbad-function-cast -Wstrict-prototypes'
-  warn_cxx='-Wextra-semi -Wnoexcept -Wundefined-func-template'
+  warn_cxx='-Wextra-semi -Wnoexcept -Wundefined-func-template -Wweak-vtables'
   # Warnings for the test suite only.
   #
   # -fno-color-diagnostics: Clang's use of colors in the error

data/README

@@ -75,48 +75,75 @@ skeletons.
 
 ## Symbols
 
+### `b4_symbol(NUM, FIELD)`
 In order to unify the handling of the various aspects of symbols (tag, type
 name, whether terminal, etc.), bison.exe defines one macro per (token,
 field), where field can `has_id`, `id`, etc.: see
-src/output.c:prepare_symbols_definitions().
+`prepare_symbols_definitions()` in `src/output.c`.
 
-The various FIELDS are:
+The macro `b4_symbol(NUM, FIELD)` gives access to the following FIELDS:
+
+- `has_id`: 0 or 1.
 
-- has_id: 0 or 1.
   Whether the symbol has an id.
-- id: string
-  If has_id, the id.  Guaranteed to be usable as a C identifier.
-  Prefixed by api.token.prefix if defined.
-- tag: string.
+
+- `id`: string
+  If has_id, the id (prefixed by api.token.prefix if defined), otherwise
+  defined as empty.  Guaranteed to be usable as a C identifier.
+
+- `tag`: string.
   A representation of the symbol.  Can be 'foo', 'foo.id', '"foo"' etc.
-- user_number: integer
+
+- `user_number`: integer
   The external number as used by yylex.  Can be ASCII code when a character,
   some number chosen by bison, or some user number in the case of
   %token FOO <NUM>.  Corresponds to yychar in yacc.c.
-- is_token: 0 or 1
+
+- `is_token`: 0 or 1
   Whether this is a terminal symbol.
-- number: integer
+
+- `number`: integer
   The internal number (computed from the external number by yytranslate).
   Corresponds to yytoken in yacc.c.  This is the same number that serves as
   key in b4_symbol(NUM, FIELD).
-- has_type: 0, 1
+
+  In bison, symbols are first assigned increasing numbers in order of
+  appearance (but tokens first, then nterms).  After grammar reduction,
+  unused nterms are then renumbered to appear last (i.e., first tokens, then
+  used nterms and finally unused nterms).  This final number NUM is the one
+  contained in this field, and it is the one used as key in `b4_symbol(NUM,
+  FIELD)`.
+
+  The code of the rule actions, however, is emitted before we know what
+  symbols are unused, so they use the original numbers.  To avoid confusion,
+  they actually use "orig NUM" instead of just "NUM".  bison also emits
+  definitions for `b4_symbol(orig NUM, number)` that map from original
+  numbers to the new ones.  `b4_symbol` actually resolves `orig NUM` in the
+  other case, i.e., `b4_symbol(orig 42, tag)` would return the tag of the
+  symbols whose original number was 42.
+
+- `has_type`: 0, 1
   Whether has a semantic value.
-- type_tag: string
+
+- `type_tag`: string
   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`
   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).
-- has_printer: 0, 1
-- printer: string
-- printer_file: string
-- printer_line: integer
+
+- `has_printer`: 0, 1
+- `printer`: string
+- `printer_file`: string
+- `printer_line`: integer
   If the symbol has a printer, everything about it.
-- has_destructor, destructor, destructor_file, destructor_line
+
+- `has_destructor`, `destructor`, `destructor_file`, `destructor_line`
   Likewise.
 
-### b4_symbol_value(VAL, [SYMBOL-NUM], [TYPE-TAG])
+### `b4_symbol_value(VAL, [SYMBOL-NUM], [TYPE-TAG])`
 Expansion of $$, $1, $<TYPE-TAG>3, etc.
 
 The semantic value from a given VAL.
@@ -127,14 +154,14 @@ The semantic value from a given VAL.
 The result can be used safely, it is put in parens to avoid nasty precedence
 issues.
 
-### b4_lhs_value(SYMBOL-NUM, [TYPE])
+### `b4_lhs_value(SYMBOL-NUM, [TYPE])`
 Expansion of `$$` or `$<TYPE>$`, for symbol `SYMBOL-NUM`.
 
-### b4_rhs_data(RULE-LENGTH, POS)
+### `b4_rhs_data(RULE-LENGTH, POS)`
 The data corresponding to the symbol `#POS`, where the current rule has
 `RULE-LENGTH` symbols on RHS.
 
-### b4_rhs_value(RULE-LENGTH, POS, SYMBOL-NUM, [TYPE])
+### `b4_rhs_value(RULE-LENGTH, POS, SYMBOL-NUM, [TYPE])`
 Expansion of `$<TYPE>POS`, where the current rule has `RULE-LENGTH` symbols
 on RHS.
 

data/skeletons/bison.m4

@@ -389,17 +389,28 @@ m4_define([b4_glr_cc_if],
 #
 # The following macros provide access to symbol related values.
 
-# _b4_symbol(NUM, FIELD)
-# ----------------------
+# __b4_symbol(NUM, FIELD)
+# -----------------------
 # Recover a FIELD about symbol #NUM.  Thanks to m4_indir, fails if
 # undefined.
-m4_define([_b4_symbol],
+m4_define([__b4_symbol],
 [m4_indir([b4_symbol($1, $2)])])
 
 
+# _b4_symbol(NUM, FIELD)
+# ----------------------
+# Recover a FIELD about symbol #NUM (or "orig NUM").  Fails if
+# undefined.
+m4_define([_b4_symbol],
+[m4_ifdef([b4_symbol($1, number)],
+          [__b4_symbol(m4_indir([b4_symbol($1, number)]), $2)],
+          [__b4_symbol([$1], [$2])])])
+
+
+
 # b4_symbol(NUM, FIELD)
 # ---------------------
-# Recover a FIELD about symbol #NUM.  Thanks to m4_indir, fails if
+# Recover a FIELD about symbol #NUM (or "orig NUM").  Fails if
 # undefined.  If FIELD = id, prepend the token prefix.
 m4_define([b4_symbol],
 [m4_case([$2],
@@ -480,7 +491,9 @@ m4_popdef([b4_actions_])dnl
 
 # _b4_symbol_case(SYMBOL-NUM)
 # ---------------------------
-# Issue a "case NUM" for SYMBOL-NUM.
+# Issue a "case NUM" for SYMBOL-NUM.  Ends with its EOL to make it
+# easier to use with m4_map, but then, use []dnl to suppress the last
+# one.
 m4_define([_b4_symbol_case],
 [case b4_symbol([$1], [number]): b4_symbol_tag_comment([$1])])
 ])

data/skeletons/c++.m4

@@ -77,11 +77,13 @@ m4_define([b4_cxx_portability],
 // Support noexcept when possible.
 #if 201103L <= YY_CPLUSPLUS
 # define YY_NOEXCEPT noexcept
+# define YY_NOTHROW
 #else
 # define YY_NOEXCEPT
-#endif[]dnl
+# define YY_NOTHROW throw ()
+#endif
 
-// Support noexcept when possible.
+// Support constexpr when possible.
 #if 201703 <= YY_CPLUSPLUS
 # define YY_CONSTEXPR constexpr
 #else
@@ -217,7 +219,14 @@ m4_define([b4_public_types_declare],
       syntax_error (]b4_locations_if([const location_type& l, ])[const std::string& m)
         : std::runtime_error (m)]b4_locations_if([
         , location (l)])[
-      {}]b4_locations_if([
+      {}
+
+      syntax_error (const syntax_error& s)
+        : std::runtime_error (s.what ())]b4_locations_if([
+        , location (s.location)])[
+      {}
+
+      ~syntax_error () YY_NOEXCEPT YY_NOTHROW;]b4_locations_if([
 
       location_type location;])[
     };
@@ -507,7 +516,7 @@ m4_define([b4_public_types_define],
 ])
 
 
-# b4_tolen_constructor_define
+# b4_token_constructor_define
 # ----------------------------
 # Define symbol constructors for all the value types.
 # Use at class-level.  Redefined in variant.hh.

data/skeletons/glr.cc

@@ -160,6 +160,9 @@ m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
   ]b4_parser_class::~b4_parser_class[ ()
   {}
 
+  ]b4_parser_class[::syntax_error::~syntax_error () YY_NOEXCEPT YY_NOTHROW
+  {}
+
   int
   ]b4_parser_class[::operator() ()
   {
@@ -246,9 +249,12 @@ b4_percent_code_get([[requires]])[
 #include <stdexcept>
 #include <string>
 
-]m4_ifdef([b4_location_file],
+]b4_cxx_portability[
+]m4_ifdef([b4_location_include],
           [[# include ]b4_location_include])[
+]b4_variant_if([b4_variant_includes])[
 
+]b4_attribute_define[
 ]b4_null_define[
 
 // Whether we are compiled with exception support.
@@ -263,6 +269,7 @@ b4_percent_code_get([[requires]])[
 ]b4_YYDEBUG_define[
 
 ]b4_namespace_open[
+
 ]b4_bison_locations_if([m4_ifndef([b4_location_file],
                                   [b4_location_define])])[
 

data/skeletons/lalr1.cc

@@ -110,7 +110,7 @@ b4_dollar_pushdef([yysym.value],
                   [$1],
                   [],
                   [yysym.location])dnl
-      _b4_symbol_case([$1])
+      _b4_symbol_case([$1])[]dnl
 b4_syncline([b4_symbol([$1], [$2_line])], [b4_symbol([$1], [$2_file])])
         b4_symbol([$1], [$2])
 b4_syncline([@oline@], [@ofile@])
@@ -562,6 +562,8 @@ m4_if(b4_prefix, [yy], [],
   ]b4_parser_class::~b4_parser_class[ ()
   {}
 
+  ]b4_parser_class[::syntax_error::~syntax_error () YY_NOEXCEPT YY_NOTHROW
+  {}
 
   /*---------------.
   | Symbol types.  |
@@ -662,10 +664,12 @@ m4_if(b4_prefix, [yy], [],
     std::ostream& yyoutput = yyo;
     YYUSE (yyoutput);
     symbol_number_type yytype = yysym.type_get ();
+#if defined __GNUC__ && ! defined __clang__ && ! defined __ICC && __GNUC__ * 100 + __GNUC_MINOR__ <= 408
     // Avoid a (spurious) G++ 4.8 warning about "array subscript is
     // below array bounds".
     if (yysym.empty ())
       std::abort ();
+#endif
     yyo << (yytype < yyntokens_ ? "token" : "nterm")
         << ' ' << yytname_[yytype] << " ("]b4_locations_if([
         << yysym.location << ": "])[;

doc/bison.texi

@@ -10272,8 +10272,8 @@ Print the name of the directory containing skeletons and XSLT.
 @item -u
 @item --update
 Update the grammar file (remove duplicates, update deprecated directives,
-etc.).  Leaves a backup of the original file with a @code{~} appended.  For
-instance:
+etc.) and exit (i.e., do not generate any of the output files).  Leaves a
+backup of the original file with a @code{~} appended.  For instance:
 
 @example
 @group
@@ -10308,26 +10308,26 @@ See the documentation of @option{--feature=fixit} below for more details.
 
 @item -y
 @itemx --yacc
-Act more like the traditional Yacc command.  This can cause different
-diagnostics to be generated, and may change behavior in other minor
-ways.  Most importantly, imitate Yacc's output file name conventions,
-so that the parser implementation file is called @file{y.tab.c}, and
-the other outputs are called @file{y.output} and @file{y.tab.h}.
-Also, if generating a deterministic parser in C, generate
-@code{#define} statements in addition to an @code{enum} to associate
-token numbers with token names.  Thus, the following shell script can
-substitute for Yacc, and the Bison distribution contains such a script
-for compatibility with POSIX:
+Act more like the traditional @command{yacc} command.  This can cause
+different diagnostics to be generated (it implies @option{-Wyacc}), and may
+change behavior in other minor ways.  Most importantly, imitate Yacc's
+output file name conventions, so that the parser implementation file is
+called @file{y.tab.c}, and the other outputs are called @file{y.output} and
+@file{y.tab.h}.  Also, if generating a deterministic parser in C, generate
+@code{#define} statements in addition to an @code{enum} to associate token
+numbers with token names.  Thus, the following shell script can substitute
+for Yacc, and the Bison distribution contains such a script for
+compatibility with POSIX:
 
 @example
 #! /bin/sh
 bison -y "$@@"
 @end example
 
-The @option{-y}/@option{--yacc} option is intended for use with
-traditional Yacc grammars.  If your grammar uses a Bison extension
-like @samp{%glr-parser}, Bison might not be Yacc-compatible even if
-this option is specified.
+The @option{-y}/@option{--yacc} option is intended for use with traditional
+Yacc grammars.  If your grammar uses Bison extensions like
+@samp{%glr-parser}, Bison might not be Yacc-compatible even if this option
+is specified.
 
 @item -W [@var{category}]
 @itemx --warnings[=@var{category}]

examples/test

@@ -15,6 +15,9 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+SHELL=/bin/sh
+export SHELL
+
 me=$(basename "$1" .test)
 medir=$(dirname "$1" | sed -e 's,.*examples/,,')
 

src/complain.c

@@ -279,15 +279,18 @@ error_message (const location *loc, warnings flags, const char *prefix,
         *indent_ptr = pos;
       else if (*indent_ptr > pos)
         fprintf (stderr, "%*s", *indent_ptr - pos, "");
-      indent_ptr = 0;
+      indent_ptr = NULL;
     }
 
   if (prefix)
     fprintf (stderr, "%s: ", prefix);
 
   vfprintf (stderr, message, args);
-  if (! (flags & silent))
+  /* Print the type of warning, only if this is not a sub message
+     (in which case the prefix is null).  */
+  if (! (flags & silent) && prefix)
     warnings_print_categories (flags, stderr);
+
   {
     size_t l = strlen (message);
     if (l < 2 || message[l - 2] != ':' || message[l - 1] != ' ')
@@ -418,8 +421,10 @@ duplicate_rule_directive (char const *directive,
                           location first, location second)
 {
   unsigned i = 0;
-  complain_indent (&second, complaint, &i, _("only one %s allowed per rule"), directive);
+  complain_indent (&second, complaint, &i,
+                   _("only one %s allowed per rule"), directive);
   i += SUB_INDENT;
-  complain_indent (&first, complaint, &i, _("previous declaration"));
+  complain_indent (&first, complaint, &i,
+                   _("previous declaration"));
   fixits_register (&second, "");
 }

src/getargs.c

@@ -287,7 +287,7 @@ Operation modes:\n\
                              and exit\n\
       --print-datadir        output directory containing skeletons and XSLT\n\
                              and exit\n\
-  -u, --update               apply fixes to the source grammar file\n\
+  -u, --update               apply fixes to the source grammar file and exit\n\
   -y, --yacc                 emulate POSIX Yacc\n\
   -W, --warnings[=CATEGORY]  report the warnings falling in CATEGORY\n\
   -f, --feature[=FEATURE]    activate miscellaneous features\n\
@@ -708,7 +708,7 @@ getargs (int argc, char *argv[])
         break;
 
       case 'y':
-        warning_argmatch ("error=yacc", 0, 6);
+        warning_argmatch ("yacc", 0, 0);
         yacc_loc = command_line_location ();
         break;
 

src/lalr.c

@@ -329,7 +329,7 @@ state_lookahead_tokens_count (state *s, bool default_reduction_only_for_accept)
           && default_reduction_only_for_accept))
     n_lookahead_tokens += rp->num;
   else
-    s->consistent = 1;
+    s->consistent = true;
 
   return n_lookahead_tokens;
 }

src/main.c

@@ -155,31 +155,34 @@ main (int argc, char *argv[])
 
   print_precedence_warnings ();
 
-  /* Output file names. */
-  compute_output_file_names ();
-
-  /* Output the detailed report on the grammar.  */
-  if (report_flag)
+  if (!update_flag)
     {
-      timevar_push (tv_report);
-      print_results ();
-      timevar_pop (tv_report);
-    }
+      /* Output file names. */
+      compute_output_file_names ();
 
-  /* Output the graph.  */
-  if (graph_flag)
-    {
-      timevar_push (tv_graph);
-      print_graph ();
-      timevar_pop (tv_graph);
-    }
+      /* Output the detailed report on the grammar.  */
+      if (report_flag)
+        {
+          timevar_push (tv_report);
+          print_results ();
+          timevar_pop (tv_report);
+        }
 
-  /* Output xml.  */
-  if (xml_flag)
-    {
-      timevar_push (tv_xml);
-      print_xml ();
-      timevar_pop (tv_xml);
+      /* Output the graph.  */
+      if (graph_flag)
+        {
+          timevar_push (tv_graph);
+          print_graph ();
+          timevar_pop (tv_graph);
+        }
+
+      /* Output xml.  */
+      if (xml_flag)
+        {
+          timevar_push (tv_xml);
+          print_xml ();
+          timevar_pop (tv_xml);
+        }
     }
 
   /* Stop if there were errors, to avoid trashing previous output
@@ -193,9 +196,12 @@ main (int argc, char *argv[])
   timevar_pop (tv_free);
 
   /* Output the tables and the parser to ftable.  In file output.  */
-  timevar_push (tv_parser);
-  output ();
-  timevar_pop (tv_parser);
+  if (!update_flag)
+    {
+      timevar_push (tv_parser);
+      output ();
+      timevar_pop (tv_parser);
+    }
 
   timevar_push (tv_free);
   nullable_free ();

src/muscle-tab.c

@@ -520,21 +520,27 @@ muscle_percent_define_insert (char const *var, location variable_loc,
 
   /* Command-line options are processed before the grammar file.  */
   bool warned = false;
-  if (how == MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE
-      && muscle_find_const (name))
+  if (how == MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE)
     {
-      muscle_percent_define_how how_old = atoi (muscle_find_const (how_name));
-      if (how_old == MUSCLE_PERCENT_DEFINE_F)
-        goto end;
-      unsigned i = 0;
-      complain_indent (&variable_loc, complaint, &i,
-                       _("%%define variable %s redefined"),
-                       quote (variable));
-      i += SUB_INDENT;
-      location loc = muscle_percent_define_get_loc (variable);
-      complain_indent (&loc, complaint, &i, _("previous definition"));
-      fixits_register (&variable_loc, "");
-      warned = true;
+      char const *current_value = muscle_find_const (name);
+      if (current_value)
+        {
+          muscle_percent_define_how how_old
+            = atoi (muscle_find_const (how_name));
+          if (how_old == MUSCLE_PERCENT_DEFINE_F)
+            goto end;
+          unsigned i = 0;
+          /* If assigning the same value, make it a warning.  */
+          warnings warn = STREQ (value, current_value) ? Wother : complaint;
+          complain_indent (&variable_loc, warn, &i,
+                           _("%%define variable %s redefined"),
+                           quote (variable));
+          i += SUB_INDENT;
+          location loc = muscle_percent_define_get_loc (variable);
+          complain_indent (&loc, warn, &i, _("previous definition"));
+          fixits_register (&variable_loc, "");
+          warned = true;
+        }
     }
 
   if (!warned && old && upd)

src/output.c

@@ -38,6 +38,7 @@
 #include "muscle-tab.h"
 #include "output.h"
 #include "reader.h"
+#include "reduce.h"
 #include "scan-code.h"    /* max_left_semantic_context */
 #include "scan-skel.h"
 #include "symtab.h"
@@ -414,6 +415,14 @@ merger_output (FILE *out)
 static void
 prepare_symbol_definitions (void)
 {
+  /* Map "orig NUM" to new numbers.  See data/README.  */
+  for (symbol_number i = ntokens; i < nsyms + nuseless_nonterminals; ++i)
+    {
+      obstack_printf (&format_obstack, "symbol(orig %d, number)", i);
+      const char *key = obstack_finish0 (&format_obstack);
+      MUSCLE_INSERT_INT (key, nterm_map ? nterm_map[i - ntokens] : i);
+    }
+
   for (int i = 0; i < nsyms; ++i)
     {
       symbol *sym = symbols[i];

src/reduce.c

@@ -259,22 +259,23 @@ reduce_grammar_tables (void)
 | Remove useless nonterminals.  |
 `------------------------------*/
 
+symbol_number *nterm_map = NULL;
+
 static void
 nonterminals_reduce (void)
 {
+  nterm_map = xnmalloc (nvars, sizeof *nterm_map);
   /* Map the nonterminals to their new index: useful first, useless
      afterwards.  Kept for later report.  */
-
-  symbol_number *nontermmap = xnmalloc (nvars, sizeof *nontermmap);
   {
     symbol_number n = ntokens;
     for (symbol_number i = ntokens; i < nsyms; ++i)
       if (bitset_test (V, i))
-        nontermmap[i - ntokens] = n++;
+        nterm_map[i - ntokens] = n++;
     for (symbol_number i = ntokens; i < nsyms; ++i)
       if (!bitset_test (V, i))
         {
-          nontermmap[i - ntokens] = n++;
+          nterm_map[i - ntokens] = n++;
           if (symbols[i]->content->status != used)
             complain (&symbols[i]->location, Wother,
                       _("nonterminal useless in grammar: %s"),
@@ -282,32 +283,30 @@ nonterminals_reduce (void)
         }
   }
 
-
   /* Shuffle elements of tables indexed by symbol number.  */
   {
     symbol **symbols_sorted = xnmalloc (nvars, sizeof *symbols_sorted);
     for (symbol_number i = ntokens; i < nsyms; ++i)
-      symbols[i]->content->number = nontermmap[i - ntokens];
+      symbols[i]->content->number = nterm_map[i - ntokens];
     for (symbol_number i = ntokens; i < nsyms; ++i)
-      symbols_sorted[nontermmap[i - ntokens] - ntokens] = symbols[i];
+      symbols_sorted[nterm_map[i - ntokens] - ntokens] = symbols[i];
     for (symbol_number i = ntokens; i < nsyms; ++i)
       symbols[i] = symbols_sorted[i - ntokens];
     free (symbols_sorted);
   }
 
+  /* Update nonterminal numbers in the RHS of the rules.  LHS are
+     pointers to the symbol structure, they don't need renumbering. */
   {
     for (rule_number r = 0; r < nrules; ++r)
       for (item_number *rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
         if (ISVAR (*rhsp))
-          *rhsp =  symbol_number_as_item_number (nontermmap[*rhsp
-                                                            - ntokens]);
-    accept->content->number = nontermmap[accept->content->number - ntokens];
+          *rhsp = symbol_number_as_item_number (nterm_map[*rhsp - ntokens]);
+    accept->content->number = nterm_map[accept->content->number - ntokens];
   }
 
   nsyms -= nuseless_nonterminals;
   nvars -= nuseless_nonterminals;
-
-  free (nontermmap);
 }
 
 
@@ -433,4 +432,6 @@ reduce_free (void)
   bitset_free (V);
   bitset_free (V1);
   bitset_free (P);
+  free (nterm_map);
+  nterm_map = NULL;
 }

src/reduce.h

@@ -32,6 +32,11 @@ bool reduce_nonterminal_useless_in_grammar (const sym_content *sym);
 
 void reduce_free (void);
 
+/** Map initial nterm numbers to the new ones.  Built by
+ * reduce_grammar.  Size nvars + nuseless_nonterminals.  */
+extern symbol_number *nterm_map;
+
 extern unsigned nuseless_nonterminals;
 extern unsigned nuseless_productions;
+
 #endif /* !REDUCE_H_ */

src/scan-code.l

@@ -648,7 +648,7 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
               untyped_var_seen = true;
           }
 
-        obstack_printf (&obstack_for_string, "]b4_lhs_value(%d, ",
+        obstack_printf (&obstack_for_string, "]b4_lhs_value(orig %d, ",
                         sym->content.sym->content->number);
         obstack_quote (&obstack_for_string, type_name);
         obstack_sgrow (&obstack_for_string, ")[");
@@ -677,7 +677,9 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
                         "]b4_rhs_value(%d, %d, ",
                         effective_rule_length, n);
         if (sym)
-          obstack_printf (&obstack_for_string, "%d, ", sym->content.sym->content->number);
+          obstack_printf (&obstack_for_string, "%s%d, ",
+                          sym->content.sym->content->class == nterm_sym ? "orig " : "",
+                          sym->content.sym->content->number);
         else
           obstack_sgrow (&obstack_for_string, "[], ");
 

src/state.c

@@ -143,7 +143,7 @@ state_new (symbol_number accessing_symbol,
   res->reductions = NULL;
   res->errs = NULL;
   res->state_list = NULL;
-  res->consistent = 0;
+  res->consistent = false;
   res->solved_conflicts = NULL;
   res->solved_conflicts_xml = NULL;
 

src/state.h

@@ -81,6 +81,8 @@
 #ifndef STATE_H_
 # define STATE_H_
 
+# include <stdbool.h>
+
 # include <bitset.h>
 
 # include "gram.h"
@@ -208,9 +210,9 @@ struct state
      store in this member a reference to the node containing each state.  */
   struct state_list *state_list;
 
-  /* If non-zero, then no lookahead sets on reduce actions are needed to
-     decide what to do in state S.  */
-  char consistent;
+  /* Whether no lookahead sets on reduce actions are needed to decide
+     what to do in state S.  */
+  bool consistent;
 
   /* If some conflicts were solved thanks to precedence/associativity,
      a human readable description of the resolution.  */

tests/actions.at

@@ -543,7 +543,7 @@ AT_DATA_GRAMMAR([[input.y]],
 
 #define YYINITDEPTH 10
 #define YYMAXDEPTH 10
-#define RANGE(Location) ]AT_LALR1_CC_IF([(Location).begin.line, (Location).end.line],
+#define RANGE(Location) ]AT_CXX_IF([(Location).begin.line, (Location).end.line],
       [(Location).first_line, (Location).last_line])[
 
 #define USE(SYM)
@@ -572,8 +572,8 @@ AT_LALR1_CC_IF([typedef yy::location YYLTYPE;])[
 /* FIXME: This %printer isn't actually tested.  */
 %printer
   {
-    ]AT_LALR1_CC_IF([yyo << $$;],
-                    [fprintf (yyo, "%d", $$)])[;
+    ]AT_CXX_IF([yyo << $$;],
+               [fprintf (yyo, "%d", $$)])[;
   }
   '(' 'x' 'y' ')' ';' thing line input '!' raise check-spontaneous-errors END
 
@@ -734,9 +734,8 @@ static
   fprintf (stderr, " (%d@%d-%d)\n", c, RANGE (]AT_LOC[));
   return source[c];
 }
-]AT_LALR1_CC_IF(
-[static bool yydebug;
-int
+]AT_LALR1_CC_IF([static bool yydebug;])[
+]AT_CXX_IF([int
 yyparse ()
 {
   yy::parser parser;
@@ -999,11 +998,14 @@ AT_CLEANUP
 AT_CHECK_PRINTER_AND_DESTRUCTOR([])
 AT_CHECK_PRINTER_AND_DESTRUCTOR([], [ with union])
 
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [ with union])
+
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"])
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], [ with union])
 
-AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser])
-AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [ with union])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr.cc"])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr.cc"], [ with union])
 
 
 

tests/headers.at

@@ -330,6 +330,7 @@ AT_CHECK([[$PERL -n -0777 -e '
       |YY_MOVE_OR_COPY
       |YY_MOVE_REF
       |YY_NOEXCEPT
+      |YY_NOTHROW
       |YY_NULLPTR
       |YY_RVREF
       |YY_\w+_INCLUDED

tests/input.at

@@ -1402,15 +1402,15 @@ without_period: "WITHOUT.PERIOD";
 AT_BISON_OPTION_POPDEFS
 
 # POSIX Yacc accept periods, but not dashes.
-AT_BISON_CHECK([--yacc input.y], [1], [],
-[[input.y:1.1-5: error: POSIX Yacc does not support %code [-Werror=yacc]
-input.y:9.8-16: error: POSIX Yacc forbids dashes in symbol names: WITH-DASH [-Werror=yacc]
-input.y:10.21-34: error: POSIX Yacc does not support string literals [-Werror=yacc]
-input.y:12.23-38: error: POSIX Yacc does not support string literals [-Werror=yacc]
-input.y:13.1-5: error: POSIX Yacc does not support %code [-Werror=yacc]
-input.y:20.8-16: error: POSIX Yacc forbids dashes in symbol names: with-dash [-Werror=yacc]
-input.y:22.15-28: error: POSIX Yacc does not support string literals [-Werror=yacc]
-input.y:24.17-32: error: POSIX Yacc does not support string literals [-Werror=yacc]
+AT_BISON_CHECK([--yacc input.y], [], [],
+[[input.y:1.1-5: warning: POSIX Yacc does not support %code [-Wyacc]
+input.y:9.8-16: warning: POSIX Yacc forbids dashes in symbol names: WITH-DASH [-Wyacc]
+input.y:10.21-34: warning: POSIX Yacc does not support string literals [-Wyacc]
+input.y:12.23-38: warning: POSIX Yacc does not support string literals [-Wyacc]
+input.y:13.1-5: warning: POSIX Yacc does not support %code [-Wyacc]
+input.y:20.8-16: warning: POSIX Yacc forbids dashes in symbol names: with-dash [-Wyacc]
+input.y:22.15-28: warning: POSIX Yacc does not support string literals [-Wyacc]
+input.y:24.17-32: warning: POSIX Yacc does not support string literals [-Wyacc]
 ]])
 
 # Dashes are fine for GNU Bison.
@@ -1740,7 +1740,7 @@ start: %empty;
 ]])
 
 AT_BISON_CHECK([[input-redefined.y]], [[1]], [],
-[[input-redefined.y:2.1-20: error: %define variable 'var' redefined
+[[input-redefined.y:2.1-20: warning: %define variable 'var' redefined [-Wother]
 input-redefined.y:1.1-20:     previous definition
 input-redefined.y:3.2-21: error: %define variable 'var' redefined
 input-redefined.y:2.1-20:     previous definition
@@ -1992,7 +1992,6 @@ AT_DATA([[input.y]],
 [[%define api.push_pull both
 %define lr.keep_unreachable_states maybe
 %define namespace "foo"
-%define api.namespace {foo}
 %define variant
 %define parser_class_name {parser}
 %%
@@ -2008,18 +2007,15 @@ input.y:2.1-40: warning: deprecated directive, use '%define lr.keep-unreachable-
 input.y:3.1-23: warning: deprecated directive, use '%define api.namespace {foo}' [-Wdeprecated]
  %define namespace "foo"
  ^~~~~~~~~~~~~~~~~~~~~~~
-input.y:4.1-27: error: %define variable 'api.namespace' redefined
- %define api.namespace {foo}
- ^~~~~~~~~~~~~~~~~~~~~~~~~~~
-input.y:3.1-23:     previous definition
- %define namespace "foo"
- ^~~~~~~~~~~~~~~~~~~~~~~
-input.y:5.1-15: warning: deprecated directive, use '%define api.value.type variant' [-Wdeprecated]
+input.y:4.1-15: warning: deprecated directive, use '%define api.value.type variant' [-Wdeprecated]
  %define variant
  ^~~~~~~~~~~~~~~
-input.y:6.1-34: warning: deprecated directive, use '%define api.parser.class {parser}' [-Wdeprecated]
+input.y:5.1-34: warning: deprecated directive, use '%define api.parser.class {parser}' [-Wdeprecated]
  %define parser_class_name {parser}
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+input.y:2.1-40: error: invalid value for %define Boolean variable 'lr.keep-unreachable-state'
+ %define lr.keep_unreachable_states maybe
+ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
@@ -2337,8 +2333,8 @@ AT_CLEANUP
 
 AT_SETUP([[Redefined %union name]])
 
-# AT_TEST(DIRECTIVES, ERROR)
-# --------------------------
+# AT_TEST(DIRECTIVES, EXIT-STATUS, ERROR)
+# ---------------------------------------
 m4_pushdef([AT_TEST],
 [AT_DATA([[input.y]],
 [$1
@@ -2346,27 +2342,28 @@ m4_pushdef([AT_TEST],
 exp: %empty;
 ])
 
-AT_BISON_CHECK([[input.y]], [[1]], [[]],
-[$2])
+AT_BISON_CHECK([[input.y]], [$2], [[]],
+[$3])
 ])
 
 AT_TEST([[%union foo {};
 %union {};
 %union foo {};
 %define api.value.union.name foo]],
-[[input.y:3.8-10: error: %define variable 'api.value.union.name' redefined
+[0],
+[[input.y:3.8-10: warning: %define variable 'api.value.union.name' redefined [-Wother]
 input.y:1.8-10:     previous definition
-input.y:4.1-32: error: %define variable 'api.value.union.name' redefined
+input.y:4.1-32: warning: %define variable 'api.value.union.name' redefined [-Wother]
 input.y:3.8-10:     previous definition
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
-AT_TEST([[%define api.value.union.name {foo}]],
+AT_TEST([[%define api.value.union.name {foo}]], [1],
 [[input.y:1.1-34: error: %define variable 'api.value.union.name' requires keyword values
 input.y:1.1-34: error: %define variable 'api.value.union.name' is not used
 ]])
 
-AT_TEST([[%define api.value.union.name "foo"]],
+AT_TEST([[%define api.value.union.name "foo"]], [1],
 [[input.y:1.1-34: error: %define variable 'api.value.union.name' requires keyword values
 input.y:1.1-34: error: %define variable 'api.value.union.name' is not used
 ]])
@@ -2503,7 +2500,7 @@ AT_DATA_GRAMMAR([[input.y]],
 %no-default_prec
 %no_default-prec
 %no_lines
-%output = "foo"
+%output = "output.c"
 %pure_parser
 %token_table
 %error-verbose
@@ -2523,15 +2520,15 @@ fix-it:"input.y":{12:1-12:11}:"%expect-rr"
 input.y:13.1-14: warning: deprecated directive: '%file-prefix =', use '%file-prefix' [-Wdeprecated]
 fix-it:"input.y":{13:1-13:15}:"%file-prefix"
 input.y:14.1-16.5: warning: duplicate directive: '%file-prefix\n =' [-Wother]
-input.y:13.1-20:       previous declaration [-Wother]
+input.y:13.1-20:       previous declaration
 fix-it:"input.y":{14:1-16:6}:""
 input.y:17.1-19: warning: deprecated directive: '%fixed-output_files', use '%fixed-output-files' [-Wdeprecated]
 fix-it:"input.y":{17:1-17:20}:"%fixed-output-files"
 input.y:18.1-19: warning: duplicate directive: '%fixed_output-files' [-Wother]
-input.y:17.1-19:     previous declaration [-Wother]
+input.y:17.1-19:     previous declaration
 fix-it:"input.y":{18:1-18:20}:""
 input.y:19.1-19: warning: duplicate directive: '%fixed-output-files' [-Wother]
-input.y:17.1-19:     previous declaration [-Wother]
+input.y:17.1-19:     previous declaration
 fix-it:"input.y":{19:1-19:20}:""
 input.y:20.1-19: warning: deprecated directive: '%name-prefix= "foo"', use '%define api.prefix {foo}' [-Wdeprecated]
 fix-it:"input.y":{20:1-20:20}:"%define api.prefix {foo}"
@@ -2547,30 +2544,35 @@ input.y:25.1-12: warning: deprecated directive: '%pure_parser', use '%pure-parse
 fix-it:"input.y":{25:1-25:13}:"%pure-parser"
 input.y:26.1-12: warning: deprecated directive: '%token_table', use '%token-table' [-Wdeprecated]
 fix-it:"input.y":{26:1-26:13}:"%token-table"
-input.y:27.1-14: error: %define variable 'parse.error' redefined
+input.y:27.1-14: warning: %define variable 'parse.error' redefined [-Wother]
 input.y:11.1-14:     previous definition
 fix-it:"input.y":{27:1-27:15}:""
 input.y:29.1-18: warning: duplicate directive: '%name-prefix "bar"' [-Wother]
-input.y:13.1-20:     previous declaration [-Wother]
+input.y:13.1-20:     previous declaration
 fix-it:"input.y":{29:1-29:19}:""
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
 AT_CHECK([cp errors-all experr])
-AT_BISON_CHECK([[-ffixit input.y]], [[1]], [[]], [experr])
+AT_BISON_CHECK([[-ffixit input.y]], [], [], [experr])
 
 AT_CHECK([[sed -e '/^fix-it:/d' errors-all >experr]])
-AT_BISON_CHECK([[input.y]], [[1]], [[]], [experr])
+AT_BISON_CHECK([[input.y]], [], [], [experr])
 
-# Update the input file.
+
+# Update the input file.  Make sure we generated nothing.
+AT_CHECK([rm -f output.c])
 AT_CHECK([cp input.y input.y.orig])
 AT_CHECK([sed -e '/fix-it/d' <errors-all >experr])
 AT_CHECK([echo "bison: file 'input.y' was updated (backup: 'input.y~')" >>experr])
-AT_BISON_CHECK([[--update input.y]], [[1]], [[]], [experr])
+AT_BISON_CHECK([[--update input.y]], [], [[]], [experr])
 
 # Check the backup.
 AT_CHECK([diff input.y.orig input.y~])
 
+# Check we did not generate any file.
+AT_CHECK([test ! -f output.c])
+
 # Check the update.
 AT_CHECK([cat input.y], [],
 [[%code top {
@@ -2591,7 +2593,7 @@ AT_CHECK([cat input.y], [],
 %no-default-prec
 %no-default-prec
 %no-lines
-%output "foo"
+%output "output.c"
 %pure-parser
 %token-table
 %glr-parser
@@ -2632,10 +2634,11 @@ AT_BISON_CHECK([[input.y]], [[1]], [[]],
 input.y:11.15-24: warning: deprecated directive: '%expect_rr', use '%expect-rr' [-Wdeprecated]
 input.y:12.15-24: warning: deprecated directive: '%expect_rr', use '%expect-rr' [-Wdeprecated]
 input.y:13.1-14: warning: deprecated directive: '%error_verbose', use '%define parse.error verbose' [-Wdeprecated]
-input.y:13.16-29: error: %define variable 'parse.error' redefined
+input.y:13.16-29: warning: %define variable 'parse.error' redefined [-Wother]
 input.y:13.1-14:      previous definition
-input.y:14.16-29: error: %define variable 'parse.error' redefined
+input.y:14.16-29: warning: %define variable 'parse.error' redefined [-Wother]
 input.y:13.16-29:     previous definition
+input.y: error: reduce/reduce conflicts: 0 found, 42 expected
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
@@ -2669,7 +2672,7 @@ AT_DATA_GRAMMAR([[input.y]],
 
 AT_BISON_CHECK([[input.y]], [[0]], [[]],
 [[input.y:14.1-15.5: warning: duplicate directive: '%file-prefix' [-Wother]
-input.y:13.1-18:       previous declaration [-Wother]
+input.y:13.1-18:       previous declaration
 input.y: warning: %expect-rr applies only to GLR parsers [-Wother]
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])

tests/reduce.at

@@ -199,6 +199,88 @@ AT_CLEANUP
 
 
 
+## --------------- ##
+## Useless Parts.  ##
+## --------------- ##
+
+AT_SETUP([Useless Parts])
+
+# We used to emit code that used symbol numbers before the useless
+# symbol elimination, hence before the renumbering of the useful
+# symbols.  As a result, the evaluation of the skeleton failed because
+# it used non existing symbol numbers.  Which is the happy scenario:
+# we could use numbers of other existing symbols...
+# http://lists.gnu.org/archive/html/bug-bison/2019-01/msg00044.html
+
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA([[input.y]],
+[[%code {
+  ]AT_YYERROR_DECLARE_EXTERN[
+  ]AT_YYLEX_DECLARE_EXTERN[
+}
+%union { void* ptr; }
+%type <ptr> used1
+%type <ptr> used2
+
+%%
+start
+ : used1
+ ;
+
+used1
+ : used2 { $$ = $1; }
+ ;
+
+unused
+ : used2
+ ;
+
+used2
+ : { $$ = YY_NULLPTR; }
+ ;
+]])
+
+AT_BISON_CHECK([[-fcaret -rall -o input.c input.y]], 0, [],
+[[input.y: warning: 1 nonterminal useless in grammar [-Wother]
+input.y: warning: 1 rule useless in grammar [-Wother]
+input.y:18.1-6: warning: nonterminal useless in grammar: unused [-Wother]
+ unused
+ ^~~~~~
+]])
+
+
+AT_CHECK([[sed -n '/^State 0/q;/^$/!p' input.output]], 0,
+[[Nonterminals useless in grammar
+   unused
+Rules useless in grammar
+    4 unused: used2
+Grammar
+    0 $accept: start $end
+    1 start: used1
+    2 used1: used2
+    3 used2: %empty
+Terminals, with rules where they appear
+$end (0) 0
+error (256)
+Nonterminals, with rules where they appear
+$accept (3)
+    on left: 0
+start (4)
+    on left: 1, on right: 0
+used1 <ptr> (5)
+    on left: 2, on right: 1
+used2 <ptr> (6)
+    on left: 3, on right: 2
+]])
+
+# Make sure the generated parser is correct.
+AT_COMPILE([input.o])
+
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP
+
+
+
 ## ------------------- ##
 ## Reduced Automaton.  ##
 ## ------------------- ##