version 3.6.3

* NEWS: Record release date.

.prev-version

@@ -1 +1 @@
-3.6.1
+3.6.2

NEWS

@@ -1,5 +1,15 @@
 GNU Bison NEWS
 
+* Noteworthy changes in release 3.6.3 (2020-06-03) [stable]
+
+** Bug fixes
+
+  Incorrect comments in the generated parsers.
+
+  Warnings in push parsers (yacc.c).
+
+  Incorrect display of gotos in LAC traces (lalr1.cc).
+
 * Noteworthy changes in release 3.6.2 (2020-05-17) [stable]
 
 ** Bug fixes

THANKS

@@ -162,6 +162,7 @@ Quoc Peyrot               [email protected]
 R Blake                   [email protected]
 Raja R Harinath           [email protected]
 Ralf Wildenhues           [email protected]
+Ryan                      [email protected]
 Rich Wilson               [email protected]
 Richard Stallman          [email protected]
 Rici Lake                 [email protected]

configure.ac

@@ -135,7 +135,9 @@ if test "$enable_gcc_warnings" = yes; then
     -Wpointer-arith -Wshadow
     -Wwrite-strings
     -wr188 -wr2259 -wr3179'
-  warn_c='-Wbad-function-cast -Wstrict-prototypes'
+  warn_c='-Wbad-function-cast
+    -Wmissing-prototypes
+    -Wstrict-prototypes'
   warn_cxx='-Wextra-semi -Wnoexcept -Wold-style-cast -Wundefined-func-template
     -Wweak-vtables'
   # Warnings for the test suite only.

data/local.mk

@@ -34,6 +34,7 @@ dist_skeletons_DATA =                           \
   data/skeletons/lalr1.java                     \
   data/skeletons/location.cc                    \
   data/skeletons/stack.hh                       \
+  data/skeletons/traceon.m4                     \
   data/skeletons/variant.hh                     \
   data/skeletons/yacc.c
 

data/skeletons/bison.m4

@@ -19,6 +19,27 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
+
+# m4_gsub(STRING, RE1, SUBST1, RE2, SUBST2, ...)
+# ----------------------------------------------
+# m4 equivalent of
+#
+#   $_ = STRING;
+#   s/RE1/SUBST1/g;
+#   s/RE2/SUBST2/g;
+#   ...
+#
+# Really similar to m4_bpatsubsts, but behaves properly with quotes.
+# See m4.at's "Generating Comments".  Super inelegant, but so far, I
+# did not find any better solution.
+m4_define([b4_gsub],
+[m4_bpatsubst(m4_bpatsubst(m4_bpatsubst([[[[$1]]]],
+                                        [$2], [$3]),
+                           [$4], [$5]),
+              [$6], [$7])])
+
+
+
 ## ---------------- ##
 ## Identification.  ##
 ## ---------------- ##

data/skeletons/c-like.m4

@@ -17,6 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+
 # _b4_comment(TEXT, OPEN, CONTINUE, END)
 # --------------------------------------
 # Put TEXT in comment.  Avoid trailing spaces: don't indent empty lines.
@@ -27,9 +28,10 @@
 #
 # Prefix all the output lines with PREFIX.
 m4_define([_b4_comment],
-[$2[]m4_bpatsubsts(m4_expand([$1]),
+[$2[]b4_gsub(m4_expand([$1]),
-                   [[*]/], [*\\/],
+            [[*]/], [*\\/],
-                   [/[*]], [/\\*], [
+            [/[*]], [/\\*],
+            [
 \(.\)], [
 $3\1])$4])
 

data/skeletons/lalr1.cc

@@ -1411,7 +1411,7 @@ b4_dollar_popdef])[]dnl
                      : yylac_stack_.back ());
         // Push the resulting state of the reduction.
         state_type state = yy_lr_goto_state_ (top_state, yyr1_[yyrule]);
-        YYCDEBUG << " G" << state;
+        YYCDEBUG << " G" << int (state);
         yylac_stack_.push_back (state);
       }
   }

data/skeletons/traceon.m4

@@ -0,0 +1,2 @@
+dnl GNU M4 treats -dV in a position-independent manner.
+m4_debugmode(V)m4_traceon()dnl

data/skeletons/yacc.c

@@ -1480,7 +1480,7 @@ yypull_parse (yypstate *yyps]b4_user_formals[)
 ]b4_parse_state_variable_macros([b4_pstate_macro_define])[
 
 /* Initialize the parser data structure.  */
-void
+static void
 yypstate_clear (yypstate *yyps)
 {
 ]b4_initialize_parser_state_variables[

doc/bison.texi

@@ -1879,6 +1879,7 @@ Here is the code for the lexical analyzer:
    and tabs, and returns 0 for end-of-input. */
 
 #include <ctype.h>
+#include <stdlib.h>
 @end group
 
 @group
@@ -1895,7 +1896,8 @@ yylex (void)
   if (c == '.' || isdigit (c))
     @{
       ungetc (c, stdin);
-      scanf ("%lf", &yylval);
+      if (scanf ("%lf", &yylval) != 1)
+        abort ();
       return NUM;
     @}
 @end group
@@ -2728,7 +2730,8 @@ yylex (void)
   if (c == '.' || isdigit (c))
     @{
       ungetc (c, stdin);
-      scanf ("%lf", &yylval.NUM);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
       return NUM;
     @}
 @end group
@@ -2755,10 +2758,10 @@ Bison generated a definition of @code{YYSTYPE} with a member named
           if (bufsize <= i)
             @{
               bufsize = 2 * bufsize + 40;
-              symbuf = realloc (symbuf, bufsize);
+              symbuf = realloc (symbuf, (size_t) bufsize);
             @}
           /* Add this character to the buffer. */
-          symbuf[i++] = c;
+          symbuf[i++] = (char) c;
           /* Get another character. */
           c = getchar ();
         @}
@@ -10629,7 +10632,7 @@ when there were errors.  No file was generated (except the reports generated
 by @option{--verbose}, etc.).  In particular, the output files that possibly
 existed were not changed.
 
-@item 63 (mistmatch)
+@item 63 (mismatch)
 when @command{bison} does not meet the version requirements of the grammar
 file. @xref{Require Decl}.  No file was generated or changed.
 @end table
@@ -15269,6 +15272,7 @@ London, Department of Computer Science, TR-00-12 (December 2000).
 @c LocalWords: YYUNDEF SymbolKind yypcontext YYENOMEM TOKENMAX getBundle
 @c LocalWords: ResourceBundle myResources getString getName getToken
 @c LocalWords: getLocation getExpectedTokens reportSyntaxError bistromathic
+@c LocalWords: TokenKind
 
 @c Local Variables:
 @c ispell-dictionary: "american"

examples/c/bistromathic/bistromathic.test

@@ -45,7 +45,7 @@ echo >perfect '> 0
 echo >ok '0'
 echo '0' | prog >effective
 
-echo "checking for readline output"
+echo "checking for readline output..."
 if diff perfect effective; then
     # Alles ist gut.
     strip_prompt=false
@@ -269,8 +269,8 @@ fi
 # On Windows10/MSYS2 the ^G coming from <tab> completion is not
 # emitted the same way
 # (https://lists.gnu.org/r/bug-bison/2020-05/msg00076.html).
-echo "checking for kernel name"
+echo "checking for kernel name... $(uname -s)"
-case `uname -s` in
+case $(uname -s) in
   (MSYS*)
     echo "SKIP: this is Windows/MSYS"
     exit $status

examples/c/bistromathic/local.mk

@@ -31,6 +31,7 @@ if ENABLE_BISTROMATHIC
     -DBISON_LOCALEDIR='"$(localdir)"'		\
     -DLOCALEDIR='"$(localdir)"'			\
     -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  %C%_bistromathic_CFLAGS = $(TEST_CFLAGS)
   %C%_bistromathic_LDADD = -lm $(LIBREADLINE) $(LIBINTL)
 endif
 

examples/c/bistromathic/parse.y

@@ -1,7 +1,6 @@
 %require "3.6"
 
 %code top {
-  #include <assert.h>
   #include <ctype.h>  // isdigit
   #include <locale.h> // LC_ALL
   #include <math.h>   // cos, sin, etc.
@@ -218,7 +217,7 @@ getsym (char const *name)
 }
 
 // How many symbols are registered.
-int
+static int
 symbol_count (void)
 {
   int res = 0;
@@ -312,7 +311,7 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
 `---------*/
 
 
-const char *
+static const char *
 error_format_string (int argc)
 {
   switch (argc)
@@ -407,7 +406,8 @@ xstrndup (const char *string, size_t n)
   const char *end = memchr (string, '\0', n);
   size_t len = end ? (size_t) (end - string) : n;
   char *new = malloc (len + 1);
-  assert (new);
+  if (!new)
+    abort ();
   new[len] = '\0';
   return memcpy (new, string, len);
 }
@@ -418,7 +418,8 @@ xstrndup (const char *string, size_t n)
 `-----------*/
 
 // Parse (and execute) this line.
-int process_line (YYLTYPE *lloc, const char *line)
+static int
+process_line (YYLTYPE *lloc, const char *line)
 {
   yypstate *ps = yypstate_new ();
   int status = 0;
@@ -433,7 +434,8 @@ int process_line (YYLTYPE *lloc, const char *line)
 }
 
 // Get the list of possible tokens after INPUT was read.
-int
+// Returns a nonnegative.
+static int
 expected_tokens (const char *input,
                  int *tokens, int ntokens)
 {
@@ -454,6 +456,8 @@ expected_tokens (const char *input,
 
   // Then query for the accepted tokens at this point.
   int res = yypstate_expected_tokens (ps, tokens, ntokens);
+  if (res < 0)
+    abort ();
   yypstate_delete (ps);
   return res;
 }
@@ -463,7 +467,7 @@ expected_tokens (const char *input,
 // TEXT is the word to complete.  We can use the entire contents of
 // rl_line_buffer in case we want to do some simple parsing.  Return
 // the array of matches, or NULL if there aren't any.
-char **
+static char **
 completion (const char *text, int start, int end)
 {
   YYDPRINTF ((stderr, "completion (\"%.*s[%.*s]%s\")\n",
@@ -473,14 +477,17 @@ completion (const char *text, int start, int end)
 
   // Get list of token numbers.
   int tokens[YYNTOKENS];
-  char *line = xstrndup (rl_line_buffer, start);
+  char *line = xstrndup (rl_line_buffer, (size_t) start);
   int ntokens = expected_tokens (line, tokens, YYNTOKENS);
   free (line);
 
   // Build MATCHES, the list of possible completions.
-  const int len = strlen (text);
+  const size_t len = strlen (text);
   // Need initial prefix and final NULL.
-  char **matches = calloc (ntokens + symbol_count () + 2, sizeof *matches);
+  char **matches
+    = calloc ((size_t) ntokens + (size_t) symbol_count () + 2, sizeof *matches);
+  if (!matches)
+    abort ();
   int match = 1;
   for (int i = 0; i < ntokens; ++i)
     switch (tokens[i])
@@ -510,9 +517,9 @@ completion (const char *text, int start, int end)
     matches[0] = strdup (text);
   else
     {
-      int lcplen = strlen (matches[1]);
+      size_t lcplen = strlen (matches[1]);
       for (int i = 2; i < match && lcplen; ++i)
-        for (int j = 0; j < lcplen; ++j)
+        for (size_t j = 0; j < lcplen; ++j)
           if (matches[1][j] != matches[i][j])
             lcplen = j;
       matches[0] = xstrndup (matches[1], lcplen);
@@ -536,7 +543,8 @@ completion (const char *text, int start, int end)
   return matches;
 }
 
-void init_readline (void)
+static void
+init_readline (void)
 {
   // Allow conditional parsing of the ~/.inputrc file.
   rl_readline_name = "bistromathic";
@@ -555,7 +563,8 @@ void init_readline (void)
 | Main.  |
 `-------*/
 
-int main (int argc, char const* argv[])
+int
+main (int argc, char const* argv[])
 {
 #if defined ENABLE_NLS && ENABLE_NLS
   // Set up internationalization.

examples/c/calc/calc.y

@@ -1,6 +1,7 @@
 %code top {
   #include <ctype.h>  /* isdigit. */
-  #include <stdio.h>  /* For printf, etc. */
+  #include <stdio.h>  /* printf. */
+  #include <stdlib.h> /* abort. */
   #include <string.h> /* strcmp. */
 
   int yylex (void);
@@ -73,7 +74,8 @@ yylex (void)
   if (c == '.' || isdigit (c))
     {
       ungetc (c, stdin);
-      scanf ("%lf", &yylval.NUM);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
       return NUM;
     }
 

examples/c/calc/local.mk

@@ -27,6 +27,7 @@ nodist_%C%_calc_SOURCES = %D%/calc.y
 
 # Don't use gnulib's system headers.
 %C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)
 
 dist_calc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
 CLEANFILES += %D%/calc.[ch] %D%/calc.output %D%/scan.c

examples/c/lexcalc/local.mk

@@ -25,6 +25,8 @@ if FLEX_WORKS
   nodist_%C%_lexcalc_SOURCES = %D%/parse.y %D%/parse.h %D%/scan.l
   # Don't use gnulib's system headers.
   %C%_lexcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_lexcalc_CFLAGS = $(TEST_CFLAGS)
 endif FLEX_WORKS
 
 %D%/parse.c: $(dependencies)

examples/c/lexcalc/scan.l

@@ -4,7 +4,7 @@
 %option nodefault noinput nounput noyywrap
 
 %{
-#include <errno.h> /* errno, ERANGE */
+#include <errno.h>  /* errno, ERANGE */
 #include <limits.h> /* INT_MIN */
 #include <stdlib.h> /* strtol */
 
@@ -12,7 +12,7 @@
 
   // Each time a rule is matched, advance the end cursor/position.
 #define YY_USER_ACTION                          \
-  yylloc->last_column += yyleng;
+  yylloc->last_column += (int) yyleng;
 
   // Move the first position onto the last.
 #define LOCATION_STEP()                         \

examples/c/mfcalc/local.mk

@@ -31,6 +31,7 @@ nodist_%C%_mfcalc_SOURCES = $(mfcalc_sources)
 %D%/mfcalc.c: $(dependencies)
 # Don't use gnulib's system headers.
 %C%_mfcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_mfcalc_CFLAGS = $(TEST_CFLAGS)
 %C%_mfcalc_LDADD = -lm
 
 dist_TESTS += %D%/mfcalc.test

examples/c/pushcalc/calc.y

@@ -1,7 +1,7 @@
 %code top {
   #include <ctype.h>  /* isdigit. */
-  #include <stdbool.h>
+  #include <stdio.h>  /* printf. */
-  #include <stdio.h>  /* For printf, etc. */
+  #include <stdlib.h> /* abort. */
   #include <string.h> /* strcmp. */
 }
 
@@ -81,7 +81,8 @@ yylex (YYSTYPE *yylval)
   if (c == '.' || isdigit (c))
     {
       ungetc (c, stdin);
-      scanf ("%lf", &yylval->NUM);
+      if (scanf ("%lf", &yylval->NUM) != 1)
+        abort ();
       return NUM;
     }
 

examples/c/pushcalc/local.mk

@@ -27,6 +27,7 @@ nodist_%C%_calc_SOURCES = %D%/calc.y
 
 # Don't use gnulib's system headers.
 %C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)
 
 dist_pushcalc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
 CLEANFILES += %D%/calc.[ch] %D%/calc.output

examples/c/reccalc/local.mk

@@ -26,6 +26,8 @@ if FLEX_WORKS
   BUILT_SOURCES += $(nodist_%C%_reccalc_SOURCES)
   # Don't use gnulib's system headers.
   %C%_reccalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_reccalc_CFLAGS = $(TEST_CFLAGS)
 endif FLEX_WORKS
 
 %D%/parse.c: $(dependencies)

examples/c/reccalc/scan.l

@@ -32,9 +32,9 @@
         do                                              \
           capacity = capacity ? 2 * capacity : 128;     \
         while (capacity < size + yyleng + 1);           \
-        str = realloc (str, capacity);                  \
+        str = realloc (str, (size_t) capacity);         \
       }                                                 \
-    memcpy (str + size, yytext, yyleng);                \
+    memcpy (str + size, yytext, (size_t) yyleng);       \
     size += yyleng;                                     \
     assert (size < capacity);                           \
   } while (0)

examples/c/rpcalc/local.mk

@@ -31,6 +31,7 @@ nodist_%C%_rpcalc_SOURCES = $(rpcalc_sources)
 %D%/rpcalc.c: $(dependencies)
 # Don't use gnulib's system headers.
 %C%_rpcalc_CPPFLAGS = -I$(top_builddir)/%D%
+%C%_rpcalc_CFLAGS = $(TEST_CFLAGS)
 %C%_rpcalc_LDADD = -lm
 
 dist_TESTS += %D%/rpcalc.test

examples/local.mk

@@ -35,6 +35,9 @@
 dist_noinst_SCRIPTS = %D%/extexi %D%/test
 TEST_LOG_COMPILER = $(SHELL) $(top_srcdir)/%D%/test
 
+TEST_CFLAGS =						\
+  $(WARN_CFLAGS) $(WARN_CFLAGS_TEST) $(WERROR_CFLAGS)
+
 AM_CXXFLAGS =							\
   $(WARN_CXXFLAGS) $(WARN_CXXFLAGS_TEST) $(WERROR_CXXFLAGS)
 

examples/test

@@ -36,10 +36,11 @@ 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"
+echo "checking for diff --strip-trailing-cr..."
 if diff --strip-trailing-cr "$1" "$1"; then
   diff_opts=--strip-trailing-cr
 fi
+echo "checking for diff --strip-trailing-cr... $diff_opts"
 
 # The exercised program.
 abs_medir=$cwd/examples/$medir

src/getargs.c

@@ -257,7 +257,8 @@ static const argmatch_trace_doc argmatch_trace_docs[] =
   { "sets",       "grammar sets: firsts, nullable etc." },
   { "muscles",    "m4 definitions passed to the skeleton" },
   { "tools",      "m4 invocation" },
-  { "m4",         "m4 traces" },
+  { "m4-early",   "m4 traces starting from the start" },
+  { "m4",         "m4 traces starting from the skeleton evaluation" },
   { "skeleton",   "skeleton postprocessing" },
   { "time",       "time consumption" },
   { "ielr",       "IELR conversion" },
@@ -279,6 +280,7 @@ static const argmatch_trace_arg argmatch_trace_args[] =
   { "sets",      trace_sets },
   { "muscles",   trace_muscles },
   { "tools",     trace_tools },
+  { "m4-early",  trace_m4_early },
   { "m4",        trace_m4 },
   { "skeleton",  trace_skeleton },
   { "time",      trace_time },

src/getargs.h

@@ -100,11 +100,12 @@ enum trace
     trace_grammar   = 1 << 7,  /**< Reading, reducing the grammar. */
     trace_time      = 1 << 8,  /**< Time consumption. */
     trace_skeleton  = 1 << 9,  /**< Skeleton postprocessing. */
-    trace_m4        = 1 << 10, /**< M4 traces. */
+    trace_m4_early  = 1 << 10, /**< M4 early traces. */
-    trace_muscles   = 1 << 11, /**< M4 definitions of the muscles. */
+    trace_m4        = 1 << 11, /**< M4 traces. */
-    trace_ielr      = 1 << 12, /**< IELR conversion. */
+    trace_muscles   = 1 << 12, /**< M4 definitions of the muscles. */
-    trace_closure   = 1 << 13, /**< Input/output of closure(). */
+    trace_ielr      = 1 << 13, /**< IELR conversion. */
-    trace_locations = 1 << 14, /**< Full display of locations. */
+    trace_closure   = 1 << 14, /**< Input/output of closure(). */
+    trace_locations = 1 << 15, /**< Full display of locations. */
     trace_all       = ~0       /**< All of the above.  */
   };
 /** What debug items bison displays during its run.  */

src/output.c

@@ -687,6 +687,7 @@ output_skeleton (void)
   char *skeldir = xpath_join (datadir, "skeletons");
   char *m4sugar = xpath_join (datadir, "m4sugar/m4sugar.m4");
   char *m4bison = xpath_join (skeldir, "bison.m4");
+  char *traceon = xpath_join (skeldir, "traceon.m4");
   char *skel = (IS_PATH_WITH_DIR (skeleton)
                 ? xstrdup (skeleton)
                 : xpath_join (skeldir, skeleton));
@@ -698,21 +699,10 @@ output_skeleton (void)
 
   /* Create an m4 subprocess connected to us via two pipes.  */
 
-  if (trace_flag & trace_tools)
-    fprintf (stderr, "running: %s %s - %s %s\n",
-             m4, m4sugar, m4bison, skel);
-
-  /* Some future version of GNU M4 (most likely 1.6) may treat the -dV in a
-     position-dependent manner.  Keep it as the first argument so that all
-     files are traced.
-
-     See the thread starting at
-     <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
-     for details.  */
   int filter_fd[2];
   pid_t pid;
   {
-    char const *argv[10];
+    char const *argv[11];
     int i = 0;
     argv[i++] = m4;
 
@@ -730,15 +720,29 @@ output_skeleton (void)
 
     argv[i++] = "-I";
     argv[i++] = datadir;
-    if (trace_flag & trace_m4)
+    /* Some future version of GNU M4 (most likely 1.6) may treat the
+       -dV in a position-dependent manner.  See the thread starting at
+       <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
+       for details.  */
+    if (trace_flag & trace_m4_early)
       argv[i++] = "-dV";
     argv[i++] = m4sugar;
     argv[i++] = "-";
     argv[i++] = m4bison;
+    if (trace_flag & trace_m4)
+      argv[i++] = traceon;
     argv[i++] = skel;
     argv[i++] = NULL;
     aver (i <= ARRAY_CARDINALITY (argv));
 
+    if (trace_flag & trace_tools)
+      {
+        fputs ("running:", stderr);
+        for (int j = 0; argv[j]; ++j)
+          fprintf (stderr, " %s", argv[j]);
+        fputc ('\n', stderr);
+      }
+
     /* The ugly cast is because gnulib gets the const-ness wrong.  */
     pid = create_pipe_bidi ("m4", m4, (char **)(void*)argv, false, true,
                             true, filter_fd);
@@ -747,6 +751,7 @@ output_skeleton (void)
   free (skeldir);
   free (m4sugar);
   free (m4bison);
+  free (traceon);
   free (skel);
 
   if (trace_flag & trace_muscles)

tests/m4.at

@@ -29,18 +29,44 @@ AT_DATA([input.m4],
 [[m4@&t@_include(b4_skeletonsdir/[c.m4])
 
 b4_output_begin([output.txt])
+
+b4_gsub([[abcd]],
+  [a], [b])
+b4_gsub([[abcd]],
+  [a], [b],
+  [b], [c],
+  [c], [d])
+
+_b4_comment([["/* () */"]])
+_b4_comment([["/* (  */"]])
+_b4_comment([["/*  ) */"]])
+_b4_comment([["/* [] */"]])
+
 b4_comment([["/* () */"]])
 b4_comment([["/* (  */"]])
 b4_comment([["/*  ) */"]])
+b4_comment([["/* [] */"]])
+
 b4_output_end([output.txt])
 ]])
 
 AT_BISON_CHECK([-S ./input.m4 input.y])
 
 AT_CHECK([cat output.txt], [],
-[/* "/\* () *\/"  */
+[[
+[bbcd]
+[dddd]
+
+"/\* () *\/"
+"/\* (  *\/"
+"/\*  ) *\/"
+"/\* [] *\/"
+
+/* "/\* () *\/"  */
 /* "/\* (  *\/"  */
 /* "/\*  ) *\/"  */
-])
+/* "/\* [] *\/"  */
+
+]])
 
 AT_CLEANUP