# Bison Regressions.                               -*- Autotest -*-

# Copyright (C) 2001-2011 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 Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

AT_BANNER([[Regression tests.]])


## ------------------ ##
## Trivial grammars.  ##
## ------------------ ##

AT_SETUP([Trivial grammars])

AT_DATA_GRAMMAR([input.y],
[[%{
void yyerror (char const *);
int yylex (void);
#define YYSTYPE int *
%}

%error-verbose

%%

program: 'x';
]])

AT_BISON_CHECK([-o input.c input.y])
AT_COMPILE([input.o], [-c input.c])
AT_COMPILE([input.o], [-DYYDEBUG -c input.c])

AT_CLEANUP



## ----------------- ##
## YYSTYPE typedef.  ##
## ----------------- ##

AT_SETUP([YYSTYPE typedef])

AT_DATA_GRAMMAR([input.y],
[[%{
void yyerror (char const *);
int yylex (void);
typedef union { char const *val; } YYSTYPE;
%}

%type <val> program

%%

program: { $$ = ""; };
]])

AT_BISON_CHECK([-o input.c input.y])
AT_COMPILE([input.o], [-c input.c])

AT_CLEANUP



## ------------------------------------- ##
## Early token definitions with --yacc.  ##
## ------------------------------------- ##


AT_SETUP([Early token definitions with --yacc])

# Found in GCJ: they expect the tokens to be defined before the user
# prologue, so that they can use the token definitions in it.

AT_DATA_GRAMMAR([input.y],
[[%{
void yyerror (const char *s);
int yylex (void);
%}

%union
{
  int val;
};
%{
#ifndef MY_TOKEN
# error "MY_TOKEN not defined."
#endif
%}
%token MY_TOKEN
%%
exp: MY_TOKEN;
%%
]])

AT_BISON_CHECK([-y -o input.c input.y])
AT_COMPILE([input.o], [-c input.c])

AT_CLEANUP



## ---------------------------------------- ##
## Early token definitions without --yacc.  ##
## ---------------------------------------- ##


AT_SETUP([Early token definitions without --yacc])

# Found in GCJ: they expect the tokens to be defined before the user
# prologue, so that they can use the token definitions in it.

AT_DATA_GRAMMAR([input.y],
[[%{
#include <stdio.h>
void yyerror (const char *s);
int yylex (void);
void print_my_token (void);
%}

%union
{
  int val;
};
%{
void
print_my_token (void)
{
  enum yytokentype my_token = MY_TOKEN;
  printf ("%d\n", my_token);
}
%}
%token MY_TOKEN
%%
exp: MY_TOKEN;
%%
]])

AT_BISON_CHECK([-o input.c input.y])
AT_COMPILE([input.o], [-c input.c])

AT_CLEANUP



## ---------------- ##
## Braces parsing.  ##
## ---------------- ##


AT_SETUP([Braces parsing])

AT_DATA([input.y],
[[/* Bison used to swallow the character after `}'. */

%%
exp: { tests = {{{{{{{{{{}}}}}}}}}}; };
%%
]])

AT_BISON_CHECK([-v -o input.c input.y])

AT_CHECK([grep 'tests = {{{{{{{{{{}}}}}}}}}};' input.c], 0, [ignore])

AT_CLEANUP


## ------------------ ##
## Duplicate string.  ##
## ------------------ ##


AT_SETUP([Duplicate string])

AT_DATA([input.y],
[[/* `Bison -v' used to dump core when two tokens are defined with the same
   string, as LE and GE below. */

%token NUM
%token LE "<="
%token GE "<="

%%
exp: '(' exp ')' | NUM ;
%%
]])

AT_BISON_CHECK([-v -o input.c input.y], 0, [],
[[input.y:6.8-14: warning: symbol `"<="' used more than once as a literal string
]])

AT_CLEANUP


## ------------------- ##
## Rule Line Numbers.  ##
## ------------------- ##

AT_SETUP([Rule Line Numbers])

AT_KEYWORDS([report])

AT_DATA([input.y],
[[%%
expr:
'a'

{

}

'b'

{

}

|


{


}

'c'

{

};
]])

AT_BISON_CHECK([-o input.c -v input.y])

# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[Grammar

    0 $accept: expr $end

    1 $@1: /* empty */

    2 expr: 'a' $@1 'b'

    3 $@2: /* empty */

    4 expr: $@2 'c'


Terminals, with rules where they appear

$end (0) 0
'a' (97) 2
'b' (98) 2
'c' (99) 4
error (256)


Nonterminals, with rules where they appear

$accept (6)
    on left: 0
expr (7)
    on left: 2 4, on right: 0
$@1 (8)
    on left: 1, on right: 2
$@2 (9)
    on left: 3, on right: 4


state 0

    0 $accept: . expr $end

    'a'  shift, and go to state 1

    $default  reduce using rule 3 ($@2)

    expr  go to state 2
    $@2   go to state 3


state 1

    2 expr: 'a' . $@1 'b'

    $default  reduce using rule 1 ($@1)

    $@1  go to state 4


state 2

    0 $accept: expr . $end

    $end  shift, and go to state 5


state 3

    4 expr: $@2 . 'c'

    'c'  shift, and go to state 6


state 4

    2 expr: 'a' $@1 . 'b'

    'b'  shift, and go to state 7


state 5

    0 $accept: expr $end .

    $default  accept


state 6

    4 expr: $@2 'c' .

    $default  reduce using rule 4 (expr)


state 7

    2 expr: 'a' $@1 'b' .

    $default  reduce using rule 2 (expr)
]])

AT_CLEANUP



## ---------------------- ##
## Mixing %token styles.  ##
## ---------------------- ##


AT_SETUP([Mixing %token styles])

# Taken from the documentation.
AT_DATA([input.y],
[[%token  <operator>  OR      "||"
%token  <operator>  LE 134  "<="
%left  OR  "<="
%%
exp: ;
%%
]])

AT_BISON_CHECK([-v -o input.c input.y])

AT_CLEANUP



## ---------------- ##
## Invalid inputs.  ##
## ---------------- ##


AT_SETUP([Invalid inputs])

AT_DATA([input.y],
[[%%
?
default: 'a' }
%&
%a-does-not-exist
%-
%{
]])

AT_BISON_CHECK([input.y], [1], [],
[[input.y:2.1: invalid character: `?'
input.y:3.14: invalid character: `}'
input.y:4.1: invalid character: `%'
input.y:4.2: invalid character: `&'
input.y:5.1-17: invalid directive: `%a-does-not-exist'
input.y:6.1-2: invalid directive: `%-'
input.y:7.1-8.0: missing `%}' at end of file
input.y:7.1-8.0: syntax error, unexpected %{...%}
]])

AT_CLEANUP


AT_SETUP([Invalid inputs with {}])

AT_DATA([input.y],
[[
%destructor
%initial-action
%lex-param
%parse-param
%printer
%union
]])

AT_BISON_CHECK([input.y], [1], [],
[[input.y:3.1-15: syntax error, unexpected %initial-action, expecting {...}
]])

AT_CLEANUP



## ------------------- ##
## Token definitions.  ##
## ------------------- ##


AT_SETUP([Token definitions])

# Bison managed, when fed with `%token 'f' "f"' to #define 'f'!
AT_DATA_GRAMMAR([input.y],
[%{
#include <stdlib.h>
#include <stdio.h>
void yyerror (const char *s);
int yylex (void);
%}
[%error-verbose
%token MYEOF 0 "end of file"
%token 'a' "a"
%token B_TOKEN "b"
%token C_TOKEN 'c'
%token 'd' D_TOKEN
%token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
%token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
%%
exp: "a" "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!";
%%
void
yyerror (char const *s)
{
  fprintf (stderr, "%s\n", s);
}

int
yylex (void)
{
  static int called;
  if (called++)
    abort ();
  return SPECIAL;
}

int
main (void)
{
  return yyparse ();
}
]])

# Checking the warning message guarantees that the trigraph "??!" isn't
# unnecessarily escaped here even though it would need to be if encoded in a
# C-string literal.  Also notice that unnecessary escaping, such as "\?", from
# the user specification is eliminated.
AT_BISON_CHECK([-o input.c input.y], [[0]], [[]],
[[input.y:22.8-14: warning: symbol SPECIAL redeclared
input.y:22.8-63: warning: symbol `"\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!"' used more than once as a literal string
]])
AT_COMPILE([input])

# Checking the error message here guarantees that yytname, which does contain
# C-string literals, does have the trigraph escaped correctly.  Thus, the
# symbol name reported by the parser is exactly the same as that reported by
# Bison itself.
AT_DATA([experr],
[[syntax error, unexpected "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!", expecting a
]])
AT_PARSER_CHECK([./input], 1, [], [experr])
AT_CLEANUP



## -------------------- ##
## Characters Escapes.  ##
## -------------------- ##


AT_SETUP([Characters Escapes])

AT_DATA_GRAMMAR([input.y],
[%{
void yyerror (const char *s);
int yylex (void);
%}
[%%
exp:
  '\'' "\'"
| '\"' "\""
| '"'  "'"
;
]])
# Pacify font-lock-mode: "

AT_BISON_CHECK([-o input.c input.y])
AT_COMPILE([input.o], [-c input.c])
AT_CLEANUP



## -------------- ##
## Web2c Report.  ##
## -------------- ##

# The generation of the reduction was once wrong in Bison, and made it
# miss some reductions.  In the following test case, the reduction on
# `undef_id_tok' in state 1 was missing.  This is stripped down from
# the actual web2c.y.

AT_SETUP([Web2c Report])

AT_KEYWORDS([report])

AT_DATA([input.y],
[[%token	undef_id_tok const_id_tok

%start CONST_DEC_PART

%%
CONST_DEC_PART:
         CONST_DEC_LIST
        ;

CONST_DEC_LIST:
	  CONST_DEC
        | CONST_DEC_LIST CONST_DEC
        ;

CONST_DEC:
	  { } undef_id_tok '=' const_id_tok ';'
        ;
%%
]])

AT_BISON_CHECK([-v input.y])
AT_CHECK([cat input.output], 0,
[[Grammar

    0 $accept: CONST_DEC_PART $end

    1 CONST_DEC_PART: CONST_DEC_LIST

    2 CONST_DEC_LIST: CONST_DEC
    3               | CONST_DEC_LIST CONST_DEC

    4 $@1: /* empty */

    5 CONST_DEC: $@1 undef_id_tok '=' const_id_tok ';'


Terminals, with rules where they appear

$end (0) 0
';' (59) 5
'=' (61) 5
error (256)
undef_id_tok (258) 5
const_id_tok (259) 5


Nonterminals, with rules where they appear

$accept (7)
    on left: 0
CONST_DEC_PART (8)
    on left: 1, on right: 0
CONST_DEC_LIST (9)
    on left: 2 3, on right: 1 3
CONST_DEC (10)
    on left: 5, on right: 2 3
$@1 (11)
    on left: 4, on right: 5


state 0

    0 $accept: . CONST_DEC_PART $end

    $default  reduce using rule 4 ($@1)

    CONST_DEC_PART  go to state 1
    CONST_DEC_LIST  go to state 2
    CONST_DEC       go to state 3
    $@1             go to state 4


state 1

    0 $accept: CONST_DEC_PART . $end

    $end  shift, and go to state 5


state 2

    1 CONST_DEC_PART: CONST_DEC_LIST .
    3 CONST_DEC_LIST: CONST_DEC_LIST . CONST_DEC

    undef_id_tok  reduce using rule 4 ($@1)
    $default      reduce using rule 1 (CONST_DEC_PART)

    CONST_DEC  go to state 6
    $@1        go to state 4


state 3

    2 CONST_DEC_LIST: CONST_DEC .

    $default  reduce using rule 2 (CONST_DEC_LIST)


state 4

    5 CONST_DEC: $@1 . undef_id_tok '=' const_id_tok ';'

    undef_id_tok  shift, and go to state 7


state 5

    0 $accept: CONST_DEC_PART $end .

    $default  accept


state 6

    3 CONST_DEC_LIST: CONST_DEC_LIST CONST_DEC .

    $default  reduce using rule 3 (CONST_DEC_LIST)


state 7

    5 CONST_DEC: $@1 undef_id_tok . '=' const_id_tok ';'

    '='  shift, and go to state 8


state 8

    5 CONST_DEC: $@1 undef_id_tok '=' . const_id_tok ';'

    const_id_tok  shift, and go to state 9


state 9

    5 CONST_DEC: $@1 undef_id_tok '=' const_id_tok . ';'

    ';'  shift, and go to state 10


state 10

    5 CONST_DEC: $@1 undef_id_tok '=' const_id_tok ';' .

    $default  reduce using rule 5 (CONST_DEC)
]])

AT_CLEANUP


## --------------- ##
## Web2c Actions.  ##
## --------------- ##

# The generation of the mapping `state -> action' was once wrong in
# extremely specific situations.  web2c.y exhibits this situation.
# Below is a stripped version of the grammar.  It looks like one can
# simplify it further, but just don't: it is tuned to exhibit a bug,
# which disapears when applying sane grammar transformations.
#
# It used to be wrong on yydefact only:
#
# static const yytype_uint8 yydefact[] =
#  {
# -       2,     0,     1,     0,     0,     2,     3,     2,     5,     4,
# +       2,     0,     1,     0,     0,     0,     3,     2,     5,     4,
#         0,     0
#  };
#
# but let's check all the tables.


AT_SETUP([Web2c Actions])

AT_KEYWORDS([report])

AT_DATA([input.y],
[[%%
statement:  struct_stat;
struct_stat:  /* empty. */ | if else;
if: "if" "const" "then" statement;
else: "else" statement;
%%
]])

AT_BISON_CHECK([-v -o input.c input.y])

# Check only the tables.
[sed -n 's/  *$//;/^static const.*\[\] =/,/^}/p' input.c >tables.c]

AT_CHECK([[cat tables.c]], 0,
[[static const yytype_uint8 yytranslate[] =
{
       0,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     2,     2,     2,     2,
       2,     2,     2,     2,     2,     2,     1,     2,     3,     4,
       5,     6
};
static const yytype_uint8 yyrline[] =
{
       0,     2,     2,     3,     3,     4,     5
};
static const char *const yytname[] =
{
  "$end", "error", "$undefined", "\"if\"", "\"const\"", "\"then\"",
  "\"else\"", "$accept", "statement", "struct_stat", "if", "else", 0
};
static const yytype_uint16 yytoknum[] =
{
       0,   256,   257,   258,   259,   260,   261
};
static const yytype_int8 yypact[] =
{
      -2,    -1,     4,    -8,     0,     2,    -8,    -2,    -8,    -2,
      -8,    -8
};
static const yytype_uint8 yydefact[] =
{
       3,     0,     0,     2,     0,     0,     1,     3,     4,     3,
       6,     5
};
static const yytype_int8 yypgoto[] =
{
      -8,    -7,    -8,    -8,    -8
};
static const yytype_int8 yydefgoto[] =
{
      -1,     2,     3,     4,     8
};
static const yytype_uint8 yytable[] =
{
      10,     1,    11,     5,     6,     0,     7,     9
};
static const yytype_int8 yycheck[] =
{
       7,     3,     9,     4,     0,    -1,     6,     5
};
static const yytype_uint8 yystos[] =
{
       0,     3,     8,     9,    10,     4,     0,     6,    11,     5,
       8,     8
};
static const yytype_uint8 yyr1[] =
{
       0,     7,     8,     9,     9,    10,    11
};
static const yytype_uint8 yyr2[] =
{
       0,     2,     1,     0,     2,     4,     2
};
]])

AT_CLEANUP


## ------------------------- ##
## yycheck Bound Violation.  ##
## ------------------------- ##


# _AT_DATA_DANCER_Y(BISON-OPTIONS)
# --------------------------------
# The following grammar, taken from Andrew Suffield's GPL'd implementation
# of DGMTP, the Dancer Generic Message Transport Protocol, used to violate
# yycheck's bounds where issuing a verbose error message.  Keep this test
# so that possible bound checking compilers could check all the skeletons.
m4_define([_AT_DATA_DANCER_Y],
[AT_DATA_GRAMMAR([dancer.y],
[%{
static int yylex (AT_LALR1_CC_IF([int *], [void]));
AT_LALR1_CC_IF([#include <cstdlib>],
[#include <stdlib.h>
#include <stdio.h>
static void yyerror (const char *);])
%}
$1
%token ARROW INVALID NUMBER STRING DATA
%defines
%verbose
%error-verbose
/* Grammar follows */
%%
line: header body
   ;

header: '<' from ARROW to '>' type ':'
   | '<' ARROW to '>' type ':'
   | ARROW to type ':'
   | type ':'
   | '<' '>'
   ;

from: DATA
   | STRING
   | INVALID
   ;

to: DATA
   | STRING
   | INVALID
   ;

type: DATA
   | STRING
   | INVALID
   ;

body: /* empty */
   | body member
   ;

member: STRING
   | DATA
   | '+' NUMBER
   | '-' NUMBER
   | NUMBER
   | INVALID
   ;
%%
AT_LALR1_CC_IF(
[/* A C++ error reporting function. */
void
yy::parser::error (const std::string& m)
{
  std::cerr << m << std::endl;
}

int
yyparse ()
{
  yy::parser parser;
#if YYDEBUG
  parser.set_debug_level (YYDEBUG);
#endif
  return parser.parse ();
}
],
[static void
yyerror (const char *s)
{
  fprintf (stderr, "%s\n", s);
}])

static int
yylex (AT_LALR1_CC_IF([int *lval], [void]))
[{
  static int const tokens[] =
    {
      ':', -1
    };
  static size_t toknum;
  ]AT_LALR1_CC_IF([*lval = 0; /* Pacify GCC.  */])[
  if (! (toknum < sizeof tokens / sizeof *tokens))
    abort ();
  return tokens[toknum++];
}]

int
main (void)
{
  return yyparse ();
}
])
])# _AT_DATA_DANCER_Y


# AT_CHECK_DANCER(BISON-OPTIONS)
# ------------------------------
# Generate the grammar, compile it, run it.
m4_define([AT_CHECK_DANCER],
[AT_SETUP([Dancer $1])
AT_BISON_OPTION_PUSHDEFS([$1])
_AT_DATA_DANCER_Y([$1])
AT_BISON_CHECK([-o dancer.c dancer.y])
AT_FULL_COMPILE([dancer])
AT_PARSER_CHECK([./dancer], 1, [],
[syntax error, unexpected ':'
])
AT_BISON_OPTION_POPDEFS
AT_CLEANUP
])

AT_CHECK_DANCER()
AT_CHECK_DANCER([%glr-parser])
AT_CHECK_DANCER([%skeleton "lalr1.cc"])


## ------------------------------------------ ##
## Diagnostic that expects two alternatives.  ##
## ------------------------------------------ ##


# _AT_DATA_EXPECT2_Y(BISON-OPTIONS)
# --------------------------------
m4_define([_AT_DATA_EXPECT2_Y],
[AT_DATA_GRAMMAR([expect2.y],
[%{
static int yylex (AT_LALR1_CC_IF([int *], [void]));
AT_LALR1_CC_IF([#include <cstdlib>],
[#include <stdio.h>
#include <stdlib.h>
static void yyerror (const char *);])
%}
$1
%defines
%error-verbose
%token A 1000
%token B

%%
program: /* empty */
 | program e ';'
 | program error ';';

e: e '+' t | t;
t: A | B;

%%
AT_LALR1_CC_IF(
[/* A C++ error reporting function. */
void
yy::parser::error (const std::string& m)
{
  std::cerr << m << std::endl;
}

int
yyparse ()
{
  yy::parser parser;
  return parser.parse ();
}
],
[static void
yyerror (const char *s)
{
  fprintf (stderr, "%s\n", s);
}])

static int
yylex (AT_LALR1_CC_IF([int *lval], [void]))
[{
  static int const tokens[] =
    {
      1000, '+', '+', -1
    };
  static size_t toknum;
  ]AT_LALR1_CC_IF([*lval = 0; /* Pacify GCC.  */])[
  if (! (toknum < sizeof tokens / sizeof *tokens))
    abort ();
  return tokens[toknum++];
}]

int
main (void)
{
  return yyparse ();
}
])
])# _AT_DATA_EXPECT2_Y


# AT_CHECK_EXPECT2(BISON-OPTIONS)
# ------------------------------
# Generate the grammar, compile it, run it.
m4_define([AT_CHECK_EXPECT2],
[AT_SETUP([Expecting two tokens $1])
AT_BISON_OPTION_PUSHDEFS([$1])
_AT_DATA_EXPECT2_Y([$1])
AT_BISON_CHECK([-o expect2.c expect2.y])
AT_FULL_COMPILE([expect2])
AT_PARSER_CHECK([./expect2], 1, [],
[syntax error, unexpected '+', expecting A or B
])
AT_BISON_OPTION_POPDEFS
AT_CLEANUP
])

AT_CHECK_EXPECT2()
AT_CHECK_EXPECT2([%glr-parser])
AT_CHECK_EXPECT2([%skeleton "lalr1.cc"])



## --------------------------------------------- ##
## Braced code in declaration in rules section.  ##
## --------------------------------------------- ##

AT_SETUP([Braced code in declaration in rules section])

# Bison once mistook braced code in a declaration in the rules section to be a
# rule action.

AT_DATA_GRAMMAR([input.y],
[[%{
#include <stdio.h>
static void yyerror (char const *msg);
static int yylex (void);
%}

%error-verbose

%%

start:
  {
    printf ("Bison would once convert this action to a midrule because of the"
	    " subsequent braced code.\n");
  }
  ;

%destructor { fprintf (stderr, "DESTRUCTOR\n"); } 'a';
%printer { fprintf (yyoutput, "PRINTER"); } 'a';

%%

static void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

static int
yylex (void)
{
  return 'a';
}

int
main (void)
{
  yydebug = 1;
  return !yyparse ();
}
]])

AT_BISON_CHECK([-t -o input.c input.y])
AT_COMPILE([input])
AT_PARSER_CHECK([./input], 0,
[[Bison would once convert this action to a midrule because of the subsequent braced code.
]],
[[Starting parse
Entering state 0
Reducing stack by rule 1 (line 20):
-> $$ = nterm start ()
Stack now 0
Entering state 1
Reading a token: Next token is token 'a' (PRINTER)
syntax error, unexpected 'a', expecting $end
Error: popping nterm start ()
Stack now 0
Cleanup: discarding lookahead token 'a' (PRINTER)
DESTRUCTOR
Stack now 0
]])

AT_CLEANUP



## --------------------------------- ##
## String alias declared after use.  ##
## --------------------------------- ##

AT_SETUP([String alias declared after use])

# Bison once incorrectly asserted that the symbol number for either a token or
# its alias was the highest symbol number so far at the point of the alias
# declaration.  That was true unless the declaration appeared after their first
# uses and other tokens appeared in between.

AT_DATA([input.y],
[[%%
start: 'a' "A" 'b';
%token 'a' "A";
]])

AT_BISON_CHECK([-t -o input.c input.y])

AT_CLEANUP



## -------------------------------- ##
## Extra lookahead sets in report.  ##
## -------------------------------- ##

AT_SETUP([[Extra lookahead sets in report]])

# Bison prints each reduction's lookahead set only next to the associated
# state's one item that (1) is associated with the same rule as the reduction
# and (2) has its dot at the end of its RHS.  Previously, Bison also
# erroneously printed the lookahead set next to all of the state's other items
# associated with the same rule.  This bug affected only the `.output' file and
# not the generated parser source code.

AT_DATA([[input.y]],
[[%%
start: a | 'a' a 'a' ;
a: 'a' ;
]])

AT_BISON_CHECK([[--report=all input.y]])
AT_CHECK([[sed -n '/^state 1$/,/^state 2$/p' input.output]], [[0]],
[[state 1

    2 start: 'a' . a 'a'
    3 a: . 'a'
    3  | 'a' .  [$end]

    'a'  shift, and go to state 4

    $default  reduce using rule 3 (a)

    a  go to state 5


state 2
]])

AT_CLEANUP



## ---------------------------------------- ##
## Token number in precedence declaration.  ##
## ---------------------------------------- ##

AT_SETUP([[Token number in precedence declaration]])

# POSIX says token numbers can be declared in %left, %right, and %nonassoc, but
# we lost this in Bison 1.50.

AT_DATA_GRAMMAR([input.y],
[[%{
  #include <stdio.h>
  void yyerror (char const *);
  int yylex (void);
%}

%error-verbose
%left TK1 1 TK2 2 "tok alias" 3

%%

start: TK1 sr_conflict "tok alias" ;

sr_conflict:
  TK2
  | TK2 "tok alias"
  ;

%%

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

int
yylex (void)
{
  static int const input[] = { 1, 2, 3, 0 };
  static int const *inputp = input;
  return *inputp++;
}

int
main (void)
{
  return yyparse ();
}
]])

AT_BISON_CHECK([[-o input.c input.y]], [[0]],,
[[input.y:24.5-19: warning: rule useless in parser due to conflicts: sr_conflict: TK2 "tok alias"
]])
AT_COMPILE([[input]])
AT_PARSER_CHECK([[./input]])

AT_CLEANUP



## --------------------------- ##
## parse-gram.y: LALR = IELR.  ##
## --------------------------- ##

# If parse-gram.y's LALR and IELR parser tables ever begin to differ, we
# need to fix parse-gram.y or start using IELR.

AT_SETUP([[parse-gram.y: LALR = IELR]])

# Avoid tests/bison's dark magic by processing a local copy of the
# grammar.  Avoid differences in synclines by telling bison that the
# output files have the same name.
[cp $abs_top_srcdir/src/parse-gram.y input.y]
AT_BISON_CHECK([[-o input.c -Dlr.type=lalr input.y]])
[mv input.c lalr.c]
AT_BISON_CHECK([[-o input.c -Dlr.type=ielr input.y]])
[mv input.c ielr.c]
AT_CHECK([[diff -u lalr.c ielr.c]])

AT_CLEANUP



## -------------------------------------------- ##
## parse.error=verbose and YYSTACK_USE_ALLOCA.  ##
## -------------------------------------------- ##

AT_SETUP([[parse.error=verbose and YYSTACK_USE_ALLOCA]])

AT_DATA_GRAMMAR([input.y],
[[%code {
  #include <stdio.h>
  void yyerror (char const *);
  int yylex (void);
  #define YYSTACK_USE_ALLOCA 1
}

%define parse.error verbose

%%

start: check syntax_error syntax_error ;

check:
{
  if (128 < sizeof yymsgbuf)
    {
      fprintf (stderr,
               "The initial size of yymsgbuf in yyparse has increased\n"
               "since this test group was last updated.  As a result,\n"
               "this test group may no longer manage to induce a\n"
               "reallocation of the syntax error message buffer.\n"
               "This test group must be adjusted to produce a longer\n"
               "error message.\n");
      YYABORT;
    }
}
;

// Induce a syntax error message whose total length is more than
// sizeof yymsgbuf in yyparse.  Each token here is 64 bytes.
syntax_error:
  "123456789112345678921234567893123456789412345678951234567896123A"
| "123456789112345678921234567893123456789412345678951234567896123B"
| error 'a' 'b' 'c'
;

%%

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

int
yylex (void)
{
  /* Induce two syntax error messages (which requires full error
     recovery by shifting 3 tokens) in order to detect any loss of the
     reallocated buffer.  */
  static char const *input = "abc";
  return *input++;
}

int
main (void)
{
  return yyparse ();
}
]])

AT_BISON_CHECK([[-o input.c input.y]])
AT_COMPILE([[input]])
AT_PARSER_CHECK([[./input]], [[1]], [],
[[syntax error, unexpected 'a', expecting 123456789112345678921234567893123456789412345678951234567896123A or 123456789112345678921234567893123456789412345678951234567896123B
syntax error, unexpected $end, expecting 123456789112345678921234567893123456789412345678951234567896123A or 123456789112345678921234567893123456789412345678951234567896123B
]])

AT_CLEANUP



## ------------------------------ ##
## parse.error=verbose overflow.  ##
## ------------------------------ ##

# Imagine the case where YYSTACK_ALLOC_MAXIMUM = YYSIZE_MAXIMUM and an
# invocation of yysyntax_error has caused yymsg_alloc to grow to exactly
# YYSTACK_ALLOC_MAXIMUM (perhaps because the normal doubling of size had
# to be clipped to YYSTACK_ALLOC_MAXIMUM).  In an old version of yacc.c,
# a subsequent invocation of yysyntax_error that overflows during its
# size calculation would return YYSIZE_MAXIMUM to yyparse.  Then,
# yyparse would invoke yyerror using the old contents of yymsg.

AT_SETUP([[parse.error=verbose overflow]])

AT_DATA_GRAMMAR([input.y],
[[%code {
  #include <stdio.h>
  void yyerror (char const *);
  int yylex (void);

  /* This prevents this test case from having to induce error messages
     large enough to overflow size_t.  */
  #define YYSIZE_T unsigned char

  /* Bring in malloc and set EXIT_SUCCESS so yacc.c doesn't try to
     provide a malloc prototype using our YYSIZE_T.  */
  #include <stdlib.h>
  #ifndef EXIT_SUCCESS
  # define EXIT_SUCCESS 0
  #endif

  /* Max depth is usually much smaller than YYSTACK_ALLOC_MAXIMUM, and
     we don't want gcc to warn everywhere this constant would be too big
     to make sense for our YYSIZE_T.  */
  #define YYMAXDEPTH 100
}

%define parse.error verbose

%%

start: syntax_error1 check syntax_error2 ;

// Induce a syntax error message whose total length causes yymsg in
// yyparse to be reallocated to size YYSTACK_ALLOC_MAXIMUM, which
// should be 255.  Each token here is 64 bytes.
syntax_error1:
  "123456789112345678921234567893123456789412345678951234567896123A"
| "123456789112345678921234567893123456789412345678951234567896123B"
| "123456789112345678921234567893123456789412345678951234567896123C"
| error 'a' 'b' 'c'
;

check:
{
  if (yymsg_alloc != YYSTACK_ALLOC_MAXIMUM
      || YYSTACK_ALLOC_MAXIMUM != YYSIZE_MAXIMUM
      || YYSIZE_MAXIMUM != 255)
    {
      fprintf (stderr,
               "The assumptions of this test group are no longer\n"
               "valid, so it may no longer catch the error it was\n"
               "designed to catch.  Specifically, the following\n"
               "values should all be 255:\n\n");
      fprintf (stderr, "  yymsg_alloc = %d\n", yymsg_alloc);
      fprintf (stderr, "  YYSTACK_ALLOC_MAXIMUM = %d\n",
               YYSTACK_ALLOC_MAXIMUM);
      fprintf (stderr, "  YYSIZE_MAXIMUM = %d\n", YYSIZE_MAXIMUM);
      YYABORT;
    }
}
;

// Now overflow.
syntax_error2:
  "123456789112345678921234567893123456789412345678951234567896123A"
| "123456789112345678921234567893123456789412345678951234567896123B"
| "123456789112345678921234567893123456789412345678951234567896123C"
| "123456789112345678921234567893123456789412345678951234567896123D"
| "123456789112345678921234567893123456789412345678951234567896123E"
;

%%

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

int
yylex (void)
{
  /* Induce two syntax error messages (which requires full error
     recovery by shifting 3 tokens).  */
  static char const *input = "abc";
  return *input++;
}

int
main (void)
{
  /* Push parsers throw away the message buffer between tokens, so skip
     this test under maintainer-push-check.  */
  if (YYPUSH)
    return 77;
  return yyparse ();
}
]])

AT_BISON_CHECK([[-o input.c input.y]])

# gcc warns about tautologies and fallacies involving comparisons for
# unsigned char.  However, it doesn't produce these same warnings for
# size_t and many other types when the warnings would seem to make just
# as much sense.  We ignore the warnings.
[CFLAGS="$NO_WERROR_CFLAGS"]
AT_COMPILE([[input]])

AT_PARSER_CHECK([[./input]], [[2]], [],
[[syntax error, unexpected 'a', expecting 123456789112345678921234567893123456789412345678951234567896123A or 123456789112345678921234567893123456789412345678951234567896123B or 123456789112345678921234567893123456789412345678951234567896123C
syntax error
memory exhausted
]])

AT_CLEANUP



## ------------------------ ##
## LAC: Exploratory stack.  ##
## ------------------------ ##

AT_SETUP([[LAC: Exploratory stack]])

m4_pushdef([AT_LAC_CHECK], [

AT_BISON_OPTION_PUSHDEFS([$1])

AT_DATA_GRAMMAR([input.y],
[[%code {
  #include <stdio.h>
  void yyerror (char const *);
  int yylex (]AT_PURE_IF([[YYSTYPE *]], [[void]])[);
}

]$1[
%define parse.error verbose
%token 'c'

%%

// default reductions in inconsistent states
// v   v v   v v v v   v v v v v v v
S: A B A A B A A A A B A A A A A A A B C C A A A A A A A A A A A A B ;
//       ^                     ^                               ^
// LAC reallocs

A: 'a' | /*empty*/ { printf ("inconsistent default reduction\n"); } ;
B: 'b' ;
C: /*empty*/ { printf ("consistent default reduction\n"); } ;

%%

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

int
yylex (]AT_PURE_IF([[YYSTYPE *v]], [[void]])[)
{
  static char const *input = "bbbbc";]AT_PURE_IF([[
  *v = 0;]])[
  return *input++;
}

int
main (void)
{
  yydebug = 1;
  return yyparse ();
}
]])

AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity-initial=1 \
                 -Dparse.lac.memory-trace=full \
                 -t -o input.c input.y]], [[0]], [],
[[input.y: conflicts: 21 shift/reduce
]])
AT_COMPILE([[input]])
AT_PARSER_CHECK([[./input > stdout.txt 2> stderr.txt]], [[1]])

# Make sure syntax error doesn't forget that 'a' is expected.  It would
# be forgotten without lookahead correction.
AT_CHECK([[grep 'syntax error,' stderr.txt]], [[0]],
[[syntax error, unexpected 'c', expecting 'a' or 'b'
]])

# Check number of default reductions in inconsistent states to be sure
# syntax error is detected before unnecessary reductions are performed.
AT_CHECK([[perl -0777 -ne 'print s/inconsistent default reduction//g;' \
           < stdout.txt || exit 77]], [[0]], [[14]])

# Check number of default reductions in consistent states to be sure
# it is performed before the syntax error is detected.
AT_CHECK([[perl -0777 -ne 'print s/\bconsistent default reduction//g;' \
           < stdout.txt || exit 77]], [[0]], [[2]])

# Check number of reallocs to be sure reallocated memory isn't somehow
# lost between LAC invocations.
AT_CHECK([[perl -0777 -ne 'print s/\(realloc//g;' < stderr.txt \
           || exit 77]], [[0]], [[3]])

AT_BISON_OPTION_POPDEFS
])

AT_LAC_CHECK([[%define api.push-pull pull]])
AT_LAC_CHECK([[%define api.push-pull pull %define api.pure]])
AT_LAC_CHECK([[%define api.push-pull both]])
AT_LAC_CHECK([[%define api.push-pull both %define api.pure]])

m4_popdef([AT_LAC_CHECK])

AT_CLEANUP



## ------------------------ ##
## LAC: Memory exhaustion.  ##
## ------------------------ ##

AT_SETUP([[LAC: Memory exhaustion]])

m4_pushdef([AT_LAC_CHECK], [

AT_DATA_GRAMMAR([input.y],
[[%code {
  #include <stdio.h>
  void yyerror (char const *);
  int yylex (void);
  #define YYMAXDEPTH 8
}

%error-verbose

%%

S: A A A A A A A A A ;
A: /*empty*/ | 'a' ;

%%

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}

int
yylex (void)
{
  static char const *input = "]$1[";
  return *input++;
}

int
main (void)
{
  yydebug = 1;
  return yyparse ();
}
]])

AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity-initial=1 \
                 -t -o input.c input.y]], [[0]], [],
[[input.y: conflicts: 8 shift/reduce
]])
AT_COMPILE([[input]])

])

# Check for memory exhaustion during parsing.
AT_LAC_CHECK([[]])
AT_PARSER_CHECK([[./input]], [[2]], [[]],
[[Starting parse
Entering state 0
Reading a token: Now at end of input.
LAC: initial context established for $end
LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max size exceeded)
memory exhausted
Cleanup: discarding lookahead token $end ()
Stack now 0
]])

# Induce an immediate syntax error with an undefined token, and check
# for memory exhaustion while building syntax error message.
AT_LAC_CHECK([[z]], [[0]])
AT_PARSER_CHECK([[./input]], [[2]], [[]],
[[Starting parse
Entering state 0
Reading a token: Next token is token $undefined ()
LAC: initial context established for $undefined
LAC: checking lookahead $undefined: Always Err
Constructing syntax error message
LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max size exceeded)
syntax error
memory exhausted
Cleanup: discarding lookahead token $undefined ()
Stack now 0
]])

m4_popdef([AT_LAC_CHECK])

AT_CLEANUP