glr.cc, yacc.c: initialize yylloc properly

[bison.git] / tests / conflicts.at

diff --git a/tests/conflicts.at b/tests/conflicts.at
index e436311fde1a1913c76c3ff4d0df92e18f6bc190..a46acc5ad74d1722de91e6c3ba225c4230bff272 100644 (file)
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -1,20 +1,20 @@
 # Exercising Bison on conflicts.                         -*- Autotest -*-
 # Exercising Bison on conflicts.                         -*- Autotest -*-

-# Copyright (C) 2002 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 2, or (at your option)
-# any later version.
+# Copyright (C) 2002-2005, 2007, 2009-2012 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.
 # 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
 # You should have received a copy of the GNU General Public License

-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-# 02111-1307, USA.
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

 
 AT_BANNER([[Conflicts.]])
 
 
 AT_BANNER([[Conflicts.]])
 


@@ -37,47 +37,39 @@ exp: e 'e';
 e: 'e' | /* Nothing. */;
 ]])
 
 e: 'e' | /* Nothing. */;
 ]])
 

-AT_CHECK([bison input.y -o input.c])
+AT_BISON_CHECK([-o input.c input.y], 0, [],
+[[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
+]])

 
 AT_CLEANUP
 
 
 AT_CLEANUP
 

+

 ## ------------------- ##
 ## %nonassoc and eof.  ##
 ## ------------------- ##
 
 AT_SETUP([%nonassoc and eof])
 
 ## ------------------- ##
 ## %nonassoc and eof.  ##
 ## ------------------- ##
 
 AT_SETUP([%nonassoc and eof])
 

-AT_DATA([input.y],
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA_GRAMMAR([input.y],

 [[
 %{
 [[
 %{

-#include <config.h>
-/* We don't need a perfect malloc for these tests. */
-#undef malloc

 #include <stdio.h>
 #include <stdio.h>

-
-#if STDC_HEADERS
-# include <stdlib.h>
-#endif
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>

 
 #define YYERROR_VERBOSE 1
 
 #define YYERROR_VERBOSE 1

-static void
-yyerror (const char *msg)
-{
-  fprintf (stderr, "%s\n", msg);
-  exit (1);
-}
-
+]AT_YYERROR_DEFINE[

 /* The current argument. */
 /* The current argument. */

-static const char *input = NULL;
+static const char *input;

 
 static int
 yylex (void)
 {
 
 static int
 yylex (void)
 {

-  /* No token stands for end of file. */
-  if (input && *input)
-    return *input++;
-  else
-    return 0;
+  static size_t toknum;
+  assert (toknum <= strlen (input));
+  return input[toknum++];

 }
 
 %}
 }
 
 %}


@@ -93,69 +85,488 @@ expr: expr '<' expr
 int
 main (int argc, const char *argv[])
 {
 int
 main (int argc, const char *argv[])
 {

-  if (argc > 1)
-    input = argv[1];
+  input = argc <= 1 ? "" : argv[1];

   return yyparse ();
 }
 ]])
   return yyparse ();
 }
 ]])

+AT_BISON_OPTION_POPDEFS

 
 

-# Specify the output files to avoid problems on different file systems.
-AT_CHECK([bison input.y -o input.c])
-AT_CHECK([$CC $CFLAGS $CPPFLAGS input.c -o input], 0, [], [ignore])
+m4_pushdef([AT_NONASSOC_AND_EOF_CHECK],
+[AT_BISON_CHECK([$1[ -o input.c input.y]])
+AT_COMPILE([input])

 
 

-AT_CHECK([./input '0<0'])
-# FIXME: This is an actual bug, but a new one, in the sense that
-# no one has ever spotted it!  The messages are *wrong*: there should
-# be nothing there, it should be expected eof.
-AT_CHECK([./input '0<0<0'], [1], [],
-         [parse error, unexpected '<', expecting '<' or '>'
+m4_pushdef([AT_EXPECTING], [m4_if($2, [correct], [[, expecting $end]])])
+
+AT_PARSER_CHECK([./input '0<0'])
+AT_PARSER_CHECK([./input '0<0<0'], [1], [],
+         [syntax error, unexpected '<'AT_EXPECTING
+])
+
+AT_PARSER_CHECK([./input '0>0'])
+AT_PARSER_CHECK([./input '0>0>0'], [1], [],
+         [syntax error, unexpected '>'AT_EXPECTING

 ])
 
 ])
 

-AT_CHECK([./input '0>0'])
-AT_CHECK([./input '0>0>0'], [1], [],
-         [parse error, unexpected '>', expecting '<' or '>'
+AT_PARSER_CHECK([./input '0<0>0'], [1], [],
+         [syntax error, unexpected '>'AT_EXPECTING

 ])
 
 ])
 

-AT_CHECK([./input '0<0>0'], [1], [],
-         [parse error, unexpected '>', expecting '<' or '>'
+m4_popdef([AT_EXPECTING])])
+
+# Expected token list is missing.
+AT_NONASSOC_AND_EOF_CHECK([], [[incorrect]])
+
+# We must disable default reductions in inconsistent states in order to
+# have an explicit list of all expected tokens.
+AT_NONASSOC_AND_EOF_CHECK([[-Dlr.default-reductions=consistent]],
+                          [[correct]])
+
+# lr.default-reductions=consistent happens to work for this test case.
+# However, for other grammars, lookahead sets can be merged for
+# different left contexts, so it is still possible to have an incorrect
+# expected list.  Canonical LR is almost a general solution (that is, it
+# can fail only when %nonassoc is used), so make sure it gives the same
+# result as above.
+AT_NONASSOC_AND_EOF_CHECK([[-Dlr.type=canonical-lr]], [[correct]])
+
+# parse.lac=full is a completely general solution that does not require
+# any of the above sacrifices.  Of course, it does not extend the
+# language-recognition power of LALR to (IE)LR, but it does ensure that
+# the reported list of expected tokens matches what the given parser
+# would have accepted in place of the unexpected token.
+AT_NONASSOC_AND_EOF_CHECK([[-Dparse.lac=full]], [[correct]])
+
+m4_popdef([AT_NONASSOC_AND_EOF_CHECK])
+
+AT_CLEANUP
+
+
+
+## -------------------------------------- ##
+## %error-verbose and consistent errors.  ##
+## -------------------------------------- ##
+
+AT_SETUP([[%error-verbose and consistent errors]])
+
+m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
+
+AT_BISON_OPTION_PUSHDEFS([$1])
+
+m4_pushdef([AT_YYLEX_PROTOTYPE],
+[AT_SKEL_CC_IF([[int yylex (yy::parser::semantic_type *lvalp)]],
+               [[int yylex (YYSTYPE *lvalp)]])])
+
+AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y],
+[AT_SKEL_JAVA_IF([[
+
+%code imports {
+  import java.io.IOException;
+}]], [[
+
+%code {]AT_SKEL_CC_IF([[
+  #include <cassert>
+  #include <string>]], [[
+  #include <assert.h>
+  #include <stdio.h>
+  ]AT_YYERROR_DECLARE])[
+  ]AT_YYLEX_PROTOTYPE[;
+  #define USE(Var)
+}
+
+]AT_SKEL_CC_IF([[%defines]], [[%define api.pure]])])[
+
+]$1[
+
+%error-verbose
+
+%%
+
+]$2[
+
+]AT_SKEL_JAVA_IF([[%code lexer {]], [[%%]])[
+
+/*--------.
+| yylex.  |
+`--------*/]AT_SKEL_JAVA_IF([[
+
+public String input = "]$3[";
+public int index = 0;
+public int yylex ()
+{
+  if (index < input.length ())
+    return input.charAt (index++);
+  else
+    return 0;
+}
+public Object getLVal ()
+{
+  return new Integer(1);
+}]], [[
+
+]AT_YYLEX_PROTOTYPE[
+{
+  static char const *input = "]$3[";
+  *lvalp = 1;
+  return *input++;
+}]])[
+]AT_YYERROR_DEFINE[
+]AT_SKEL_JAVA_IF([[
+};
+
+%%]])[
+
+/*-------.
+| main.  |
+`-------*/]AT_SKEL_JAVA_IF([[
+
+class input
+{
+  public static void main (String args[]) throws IOException
+  {
+    YYParser p = new YYParser ();
+    p.parse ();
+  }
+}]], [AT_SKEL_CC_IF([[
+
+int
+main (void)
+{
+  yy::parser parser;
+  return parser.parse ();
+}]], [[
+
+int
+main (void)
+{
+  return yyparse ();
+}]])])[
+]])
+
+AT_FULL_COMPILE([[input]])
+
+m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']],
+                                  $5, [a],  [[, expecting 'a']],
+                                  $5, [b],  [[, expecting 'b']])])
+
+AT_SKEL_JAVA_IF([AT_JAVA_PARSER_CHECK([[input]], [[0]]],
+                [AT_PARSER_CHECK([[./input]], [[1]]]),
+[[]],
+[[syntax error, unexpected ]$4[]AT_EXPECTING[
+]])
+
+m4_popdef([AT_EXPECTING])
+m4_popdef([AT_YYLEX_PROTOTYPE])
+AT_BISON_OPTION_POPDEFS
+

 ])
 
 ])
 

+m4_pushdef([AT_PREVIOUS_STATE_GRAMMAR],
+[[%nonassoc 'a';
+
+start: consistent-error-on-a-a 'a' ;
+
+consistent-error-on-a-a:
+    'a' default-reduction
+  | 'a' default-reduction 'a'
+  | 'a' shift
+  ;
+
+default-reduction: /*empty*/ ;
+shift: 'b' ;
+
+// Provide another context in which all rules are useful so that this
+// test case looks a little more realistic.
+start: 'b' consistent-error-on-a-a 'c' ;
+]])
+
+m4_pushdef([AT_PREVIOUS_STATE_INPUT], [[a]])
+
+# Unfortunately, no expected tokens are reported even though 'b' can be
+# accepted.  Nevertheless, the main point of this test is to make sure
+# that at least the unexpected token is reported.  In a previous version
+# of Bison, it wasn't reported because the error is detected in a
+# consistent state with an error action, and that case always triggered
+# the simple "syntax error" message.
+#
+# The point isn't to test IELR here, but state merging happens to
+# complicate this example.
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %glr-parser]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %language "c++"]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %language "java"]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[end of input]], [[none]])
+
+# Even canonical LR doesn't foresee the error for 'a'!
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %define lr.default-reductions consistent]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[ab]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %define lr.default-reductions accepting]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[ab]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[ab]])
+
+# Only LAC gets it right.
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr
+                             %define parse.lac full]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[b]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %define parse.lac full]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[b]])
+
+m4_popdef([AT_PREVIOUS_STATE_GRAMMAR])
+m4_popdef([AT_PREVIOUS_STATE_INPUT])
+
+m4_pushdef([AT_USER_ACTION_GRAMMAR],
+[[%nonassoc 'a';
+
+// If $$ = 0 here, then we know that the 'a' destructor is being invoked
+// incorrectly for the 'b' set in the semantic action below.  All 'a'
+// tokens are returned by yylex, which sets $$ = 1.
+%destructor {
+  if (!$$)
+    fprintf (stderr, "Wrong destructor.\n");
+} 'a';
+
+// Rather than depend on an inconsistent state to induce reading a
+// lookahead as in the previous grammar, just assign the lookahead in a
+// semantic action.  That lookahead isn't needed before either error
+// action is encountered.  In a previous version of Bison, this was a
+// problem as it meant yychar was not translated into yytoken before
+// either error action.  The second error action thus invoked a
+// destructor that it selected according to the incorrect yytoken.  The
+// first error action would have reported an incorrect unexpected token
+// except that, due to the bug described in the previous grammar, the
+// unexpected token was not reported at all.
+start: error-reduce consistent-error 'a' { USE ($][3); } ;
+
+error-reduce:
+  'a' 'a' consistent-reduction consistent-error 'a'
+  { USE (($][1, $][2, $][5)); }
+| 'a' error
+  { USE ($][1); }
+;
+
+consistent-reduction: /*empty*/ {
+  assert (yychar == ]AT_SKEL_CC_IF([[yyempty_]], [[YYEMPTY]])[);
+  yylval = 0;
+  yychar = 'b';
+} ;
+
+consistent-error:
+  'a' { USE ($][1); }
+| /*empty*/ %prec 'a'
+;
+
+// Provide another context in which all rules are useful so that this
+// test case looks a little more realistic.
+start: 'b' consistent-error 'b' ;
+]])
+m4_pushdef([AT_USER_ACTION_INPUT], [[aa]])
+
+AT_CONSISTENT_ERRORS_CHECK([[]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%glr-parser]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%language "c++"]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+# No Java test because yychar cannot be manipulated by users.
+
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions consistent]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+
+# Canonical LR doesn't foresee the error for 'a'!
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions accepting]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [[$end]], [[a]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [[$end]], [[a]])
+
+AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full
+                             %define lr.default-reductions accepting]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [[$end]], [[none]])
+
+m4_popdef([AT_USER_ACTION_GRAMMAR])
+m4_popdef([AT_USER_ACTION_INPUT])
+
+m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
+

 AT_CLEANUP
 
 
 
 AT_CLEANUP
 
 
 

+## ------------------------------------------------------- ##
+## LAC: %nonassoc requires splitting canonical LR states.  ##
+## ------------------------------------------------------- ##
+
+# This test case demonstrates that, when %nonassoc is used, canonical
+# LR(1) parser table construction followed by conflict resolution
+# without further state splitting is not always sufficient to produce a
+# parser that can detect all syntax errors as soon as possible on one
+# token of lookahead.  However, LAC solves the problem completely even
+# with minimal LR parser tables.
+
+AT_SETUP([[LAC: %nonassoc requires splitting canonical LR states]])
+AT_BISON_OPTION_PUSHDEFS
+AT_DATA_GRAMMAR([[input.y]],
+[[%code {
+  #include <stdio.h>
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
+}
+
+%error-verbose
+%nonassoc 'a'
+
+%%
+
+start:
+  'a' problem 'a' // First context.
+| 'b' problem 'b' // Second context.
+| 'c' reduce-nonassoc // Just makes reduce-nonassoc useful.
+;
+
+problem:
+  look reduce-nonassoc
+| look 'a'
+| look 'b'
+;
+
+// For the state reached after shifting the 'a' in these productions,
+// lookahead sets are the same in both the first and second contexts.
+// Thus, canonical LR reuses the same state for both contexts.  However,
+// the lookahead 'a' for the reduction "look: 'a'" later becomes an
+// error action only in the first context.  In order to immediately
+// detect the syntax error on 'a' here for only the first context, this
+// canonical LR state would have to be split into two states, and the
+// 'a' lookahead would have to be removed from only one of the states.
+look:
+  'a' // Reduction lookahead set is always ['a', 'b'].
+| 'a' 'b'
+| 'a' 'c' // 'c' is forgotten as an expected token.
+;
+
+reduce-nonassoc: %prec 'a';
+
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE(["aaa"])[
+
+int
+main (void)
+{
+  return yyparse ();
+}
+]])
+AT_BISON_OPTION_POPDEFS
+
+# Show canonical LR's failure.
+AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
+               [[0]], [[]],
+[[input.y: conflicts: 2 shift/reduce
+]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[1]], [[]],
+[[syntax error, unexpected 'a', expecting 'b'
+]])
+
+# It's corrected by LAC.
+AT_BISON_CHECK([[-Dlr.type=canonical-lr -Dparse.lac=full \
+                 -o input.c input.y]], [[0]], [[]],
+[[input.y: conflicts: 2 shift/reduce
+]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[1]], [[]],
+[[syntax error, unexpected 'a', expecting 'b' or 'c'
+]])
+
+# IELR is sufficient when LAC is used.
+AT_BISON_CHECK([[-Dlr.type=ielr -Dparse.lac=full -o input.c input.y]],
+               [[0]], [[]],
+[[input.y: conflicts: 2 shift/reduce
+]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[1]], [[]],
+[[syntax error, unexpected 'a', expecting 'b' or 'c'
+]])
+
+AT_CLEANUP
+

 ## ------------------------- ##
 ## Unresolved SR Conflicts.  ##
 ## ------------------------- ##
 
 AT_SETUP([Unresolved SR Conflicts])
 
 ## ------------------------- ##
 ## Unresolved SR Conflicts.  ##
 ## ------------------------- ##
 
 AT_SETUP([Unresolved SR Conflicts])
 

+AT_KEYWORDS([report])
+

 AT_DATA([input.y],
 [[%token NUM OP
 %%
 exp: exp OP exp | NUM;
 ]])
 
 AT_DATA([input.y],
 [[%token NUM OP
 %%
 exp: exp OP exp | NUM;
 ]])
 

-AT_CHECK([bison input.y -o input.c -v], 0, [],
-[input.y contains 1 shift/reduce conflict.
+AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
+[input.y: conflicts: 1 shift/reduce

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

-[[State 5 contains 1 shift/reduce conflict.
+[[State 5 conflicts: 1 shift/reduce

 
 
 Grammar
 
 
 
 Grammar
 

-  Number, Line, Rule
-    0   3 $axiom -> exp $
-    1   3 exp -> exp OP exp
-    2   3 exp -> NUM
+    0 $accept: exp $end
+
+    1 exp: exp OP exp
+    2    | NUM

 
 
 Terminals, with rules where they appear
 
 
 
 Terminals, with rules where they appear
 

-$ (0) 0
+$end (0) 0

 error (256)
 NUM (258) 2
 OP (259) 1
 error (256)
 NUM (258) 2
 OP (259) 1


@@ -163,7 +574,7 @@ OP (259) 1
 
 Nonterminals, with rules where they appear
 
 
 Nonterminals, with rules where they appear
 

-$axiom (5)
+$accept (5)

     on left: 0
 exp (6)
     on left: 1 2, on right: 0 1
     on left: 0
 exp (6)
     on left: 1 2, on right: 0 1


@@ -171,97 +582,94 @@ exp (6)
 
 state 0
 
 
 state 0
 

-    $axiom  ->  . exp $   (rule 0)
-
-    NUM        shift, and go to state 1
+    0 $accept: . exp $end
+    1 exp: . exp OP exp
+    2    | . NUM

 
 

-    exp        go to state 2
+    NUM  shift, and go to state 1

 
 

+    exp  go to state 2

 
 
 state 1
 
 
 
 state 1
 

-    exp  ->  NUM .   (rule 2)
-
-    $default   reduce using rule 2 (exp)
+    2 exp: NUM .

 
 

+    $default  reduce using rule 2 (exp)

 
 
 state 2
 
 
 
 state 2
 

-    $axiom  ->  exp . $   (rule 0)
-    exp  ->  exp . OP exp   (rule 1)
-
-    $          shift, and go to state 3
-    OP         shift, and go to state 4
+    0 $accept: exp . $end
+    1 exp: exp . OP exp

 
 

+    $end  shift, and go to state 3
+    OP    shift, and go to state 4

 
 
 state 3
 
 
 
 state 3
 

-    $axiom  ->  exp $ .   (rule 0)
+    0 $accept: exp $end .

 
 

-    $default   accept
+    $default  accept

 
 
 state 4
 
 
 
 state 4
 

-    exp  ->  exp OP . exp   (rule 1)
-
-    NUM        shift, and go to state 1
+    1 exp: . exp OP exp
+    1    | exp OP . exp
+    2    | . NUM

 
 

-    exp        go to state 5
+    NUM  shift, and go to state 1

 
 

+    exp  go to state 5

 
 
 state 5
 
 
 
 state 5
 

-    exp  ->  exp . OP exp   (rule 1)
-    exp  ->  exp OP exp .   (rule 1)
-
-    OP         shift, and go to state 4
-
-    OP         [reduce using rule 1 (exp)]
-    $default   reduce using rule 1 (exp)
-
+    1 exp: exp . OP exp
+    1    | exp OP exp .  [$end, OP]

 
 

+    OP  shift, and go to state 4

 
 

+    OP        [reduce using rule 1 (exp)]
+    $default  reduce using rule 1 (exp)

 ]])
 
 AT_CLEANUP
 
 
 ]])
 
 AT_CLEANUP
 
 

-## --------------------- ##
-## Solved SR Conflicts.  ##
-## --------------------- ##

 
 

-AT_SETUP([Solved SR Conflicts])
+## ----------------------- ##
+## Resolved SR Conflicts.  ##
+## ----------------------- ##
+
+AT_SETUP([Resolved SR Conflicts])
+
+AT_KEYWORDS([report])

 
 AT_DATA([input.y],
 [[%token NUM OP
 
 AT_DATA([input.y],
 [[%token NUM OP

-%right OP
+%left OP

 %%
 exp: exp OP exp | NUM;
 ]])
 
 %%
 exp: exp OP exp | NUM;
 ]])
 

-AT_CHECK([bison input.y -o input.c -v], 0, [], [])
+AT_BISON_CHECK([-o input.c --report=all input.y])

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

-[[Conflict in state 5 between rule 2 and token OP resolved as shift.
-
+[[Grammar

 
 

-Grammar
+    0 $accept: exp $end

 
 

-  Number, Line, Rule
-    0   4 $axiom -> exp $
-    1   4 exp -> exp OP exp
-    2   4 exp -> NUM
+    1 exp: exp OP exp
+    2    | NUM

 
 
 Terminals, with rules where they appear
 
 
 
 Terminals, with rules where they appear
 

-$ (0) 0
+$end (0) 0

 error (256)
 NUM (258) 2
 OP (259) 1
 error (256)
 NUM (258) 2
 OP (259) 1


@@ -269,7 +677,7 @@ OP (259) 1
 
 Nonterminals, with rules where they appear
 
 
 Nonterminals, with rules where they appear
 

-$axiom (5)
+$accept (5)

     on left: 0
 exp (6)
     on left: 1 2, on right: 0 1
     on left: 0
 exp (6)
     on left: 1 2, on right: 0 1


@@ -277,60 +685,195 @@ exp (6)
 
 state 0
 
 
 state 0
 

-    $axiom  ->  . exp $   (rule 0)
+    0 $accept: . exp $end
+    1 exp: . exp OP exp
+    2    | . NUM

 
 

-    NUM        shift, and go to state 1
-
-    exp        go to state 2
+    NUM  shift, and go to state 1

 
 

+    exp  go to state 2

 
 
 state 1
 
 
 
 state 1
 

-    exp  ->  NUM .   (rule 2)
-
-    $default   reduce using rule 2 (exp)
+    2 exp: NUM .

 
 

+    $default  reduce using rule 2 (exp)

 
 
 state 2
 
 
 
 state 2
 

-    $axiom  ->  exp . $   (rule 0)
-    exp  ->  exp . OP exp   (rule 1)
-
-    $          shift, and go to state 3
-    OP         shift, and go to state 4
+    0 $accept: exp . $end
+    1 exp: exp . OP exp

 
 

+    $end  shift, and go to state 3
+    OP    shift, and go to state 4

 
 
 state 3
 
 
 
 state 3
 

-    $axiom  ->  exp $ .   (rule 0)
+    0 $accept: exp $end .

 
 

-    $default   accept
+    $default  accept

 
 
 state 4
 
 
 
 state 4
 

-    exp  ->  exp OP . exp   (rule 1)
+    1 exp: . exp OP exp
+    1    | exp OP . exp
+    2    | . NUM

 
 

-    NUM        shift, and go to state 1
-
-    exp        go to state 5
+    NUM  shift, and go to state 1

 
 

+    exp  go to state 5

 
 
 state 5
 
 
 
 state 5
 

-    exp  ->  exp . OP exp   (rule 1)
-    exp  ->  exp OP exp .   (rule 1)
+    1 exp: exp . OP exp
+    1    | exp OP exp .  [$end, OP]
+
+    $default  reduce using rule 1 (exp)
+
+    Conflict between rule 1 and token OP resolved as reduce (%left OP).
+]])

 
 

-    OP         shift, and go to state 4
+AT_CLEANUP

 
 

-    $default   reduce using rule 1 (exp)

 
 

+## -------------------------------- ##
+## Defaulted Conflicted Reduction.  ##
+## -------------------------------- ##
+
+# When there are RR conflicts, some rules are disabled.  Usually it is
+# simply displayed as:
+#
+#    $end           reduce using rule 3 (num)
+#    $end           [reduce using rule 4 (id)]
+#
+# But when `reduce 3' is the default action, we'd produce:
+#
+#    $end           [reduce using rule 4 (id)]
+#    $default    reduce using rule 3 (num)
+#
+# In this precise case (a reduction is masked by the default
+# reduction), we make the `reduce 3' explicit:
+#
+#    $end           reduce using rule 3 (num)
+#    $end           [reduce using rule 4 (id)]
+#    $default    reduce using rule 3 (num)
+#
+# Maybe that's not the best display, but then, please propose something
+# else.
+
+AT_SETUP([Defaulted Conflicted Reduction])
+AT_KEYWORDS([report])

 
 

+AT_DATA([input.y],
+[[%%
+exp: num | id;
+num: '0';
+id : '0';
+%%
+]])

 
 

+AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
+[[input.y: conflicts: 1 reduce/reduce
+input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
+]])
+
+# Check the contents of the report.
+AT_CHECK([cat input.output], [],
+[[Rules useless in parser due to conflicts
+
+    4 id: '0'
+
+
+State 1 conflicts: 1 reduce/reduce
+
+
+Grammar
+
+    0 $accept: exp $end
+
+    1 exp: num
+    2    | id
+
+    3 num: '0'
+
+    4 id: '0'
+
+
+Terminals, with rules where they appear
+
+$end (0) 0
+'0' (48) 3 4
+error (256)
+
+
+Nonterminals, with rules where they appear
+
+$accept (4)
+    on left: 0
+exp (5)
+    on left: 1 2, on right: 0
+num (6)
+    on left: 3, on right: 1
+id (7)
+    on left: 4, on right: 2
+
+
+state 0
+
+    0 $accept: . exp $end
+    1 exp: . num
+    2    | . id
+    3 num: . '0'
+    4 id: . '0'
+
+    '0'  shift, and go to state 1
+
+    exp  go to state 2
+    num  go to state 3
+    id   go to state 4
+
+
+state 1
+
+    3 num: '0' .  [$end]
+    4 id: '0' .  [$end]
+
+    $end      reduce using rule 3 (num)
+    $end      [reduce using rule 4 (id)]
+    $default  reduce using rule 3 (num)
+
+
+state 2
+
+    0 $accept: exp . $end
+
+    $end  shift, and go to state 5
+
+
+state 3
+
+    1 exp: num .
+
+    $default  reduce using rule 1 (exp)
+
+
+state 4
+
+    2 exp: id .
+
+    $default  reduce using rule 2 (exp)
+
+
+state 5
+
+    0 $accept: exp $end .
+
+    $default  accept

 ]])
 
 AT_CLEANUP
 ]])
 
 AT_CLEANUP


@@ -351,9 +894,9 @@ AT_DATA([input.y],
 exp: exp OP exp | NUM;
 ]])
 
 exp: exp OP exp | NUM;
 ]])
 

-AT_CHECK([bison input.y -o input.c], 1, [],
-[input.y contains 1 shift/reduce conflict.
-expected 0 shift/reduce conflicts
+AT_BISON_CHECK([-o input.c input.y], 1, [],
+[input.y: conflicts: 1 shift/reduce
+input.y: expected 0 shift/reduce conflicts

 ])
 AT_CLEANUP
 
 ])
 AT_CLEANUP
 


@@ -371,7 +914,7 @@ AT_DATA([input.y],
 exp: exp OP exp | NUM;
 ]])
 
 exp: exp OP exp | NUM;
 ]])
 

-AT_CHECK([bison input.y -o input.c], 0)
+AT_BISON_CHECK([-o input.c input.y])

 AT_CLEANUP
 
 
 AT_CLEANUP
 
 


@@ -388,8 +931,580 @@ AT_DATA([input.y],
 exp: exp OP exp | NUM;
 ]])
 
 exp: exp OP exp | NUM;
 ]])
 

-AT_CHECK([bison input.y -o input.c], 1, [],
-[input.y contains 1 shift/reduce conflict.
-expected 2 shift/reduce conflicts
+AT_BISON_CHECK([-o input.c input.y], 1, [],
+[input.y: conflicts: 1 shift/reduce
+input.y: expected 2 shift/reduce conflicts

 ])
 AT_CLEANUP
 ])
 AT_CLEANUP

+
+
+## ------------------------------- ##
+## %expect with reduce conflicts.  ##
+## ------------------------------- ##
+
+AT_SETUP([%expect with reduce conflicts])
+
+AT_DATA([input.y],
+[[%expect 0
+%%
+program: a 'a' | a a;
+a: 'a';
+]])
+
+AT_BISON_CHECK([-o input.c input.y], 1, [],
+[input.y: conflicts: 1 reduce/reduce
+input.y: expected 0 reduce/reduce conflicts
+])
+AT_CLEANUP
+
+
+## ------------------------- ##
+## %prec with user strings.  ##
+## ------------------------- ##
+
+AT_SETUP([%prec with user string])
+
+AT_DATA([[input.y]],
+[[%%
+exp:
+  "foo" %prec "foo"
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+AT_CLEANUP
+
+
+## -------------------------------- ##
+## %no-default-prec without %prec.  ##
+## -------------------------------- ##
+
+AT_SETUP([%no-default-prec without %prec])
+
+AT_DATA([[input.y]],
+[[%left '+'
+%left '*'
+
+%%
+
+%no-default-prec;
+
+e:   e '+' e
+   | e '*' e
+   | '0'
+   ;
+]])
+
+AT_BISON_CHECK([-o input.c input.y], 0, [],
+[[input.y: conflicts: 4 shift/reduce
+]])
+AT_CLEANUP
+
+
+## ----------------------------- ##
+## %no-default-prec with %prec.  ##
+## ----------------------------- ##
+
+AT_SETUP([%no-default-prec with %prec])
+
+AT_DATA([[input.y]],
+[[%left '+'
+%left '*'
+
+%%
+
+%no-default-prec;
+
+e:   e '+' e %prec '+'
+   | e '*' e %prec '*'
+   | '0'
+   ;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+AT_CLEANUP
+
+
+## --------------- ##
+## %default-prec.  ##
+## --------------- ##
+
+AT_SETUP([%default-prec])
+
+AT_DATA([[input.y]],
+[[%left '+'
+%left '*'
+
+%%
+
+%default-prec;
+
+e:   e '+' e
+   | e '*' e
+   | '0'
+   ;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+AT_CLEANUP
+
+
+## ---------------------------------------------- ##
+## Unreachable States After Conflict Resolution.  ##
+## ---------------------------------------------- ##
+
+AT_SETUP([[Unreachable States After Conflict Resolution]])
+
+# If conflict resolution makes states unreachable, remove those states, report
+# rules that are then unused, and don't report conflicts in those states.  Test
+# what happens when a nonterminal becomes useless as a result of state removal
+# since that causes lalr.o's goto map to be rewritten.
+
+AT_DATA([[input.y]],
+[[%output "input.c"
+%left 'a'
+
+%%
+
+start: resolved_conflict 'a' reported_conflicts 'a' ;
+
+/* S/R conflict resolved as reduce, so the state with item
+ * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
+ * unreachable, and the associated production is useless.  */
+resolved_conflict:
+    'a' unreachable1
+  | %prec 'a'
+  ;
+
+/* S/R conflict that need not be reported since it is unreachable because of
+ * the previous conflict resolution.  Nonterminal unreachable1 and all its
+ * productions are useless.  */
+unreachable1:
+    'a' unreachable2
+  |
+  ;
+
+/* Likewise for a R/R conflict and nonterminal unreachable2.  */
+unreachable2: | ;
+
+/* Make sure remaining S/R and R/R conflicts are still reported correctly even
+ * when their states are renumbered due to state removal.  */
+reported_conflicts:
+    'a'
+  | 'a'
+  |
+  ;
+
+]])
+
+AT_BISON_CHECK([[--report=all input.y]], 0, [],
+[[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
+input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
+input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
+input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
+input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
+input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
+]])
+
+AT_CHECK([[cat input.output]], 0,
+[[Rules useless in parser due to conflicts
+
+    2 resolved_conflict: 'a' unreachable1
+
+    4 unreachable1: 'a' unreachable2
+    5             | /* empty */
+
+    6 unreachable2: /* empty */
+    7             | /* empty */
+
+    9 reported_conflicts: 'a'
+   10                   | /* empty */
+
+
+State 4 conflicts: 1 shift/reduce
+State 5 conflicts: 1 reduce/reduce
+
+
+Grammar
+
+    0 $accept: start $end
+
+    1 start: resolved_conflict 'a' reported_conflicts 'a'
+
+    2 resolved_conflict: 'a' unreachable1
+    3                  | /* empty */
+
+    4 unreachable1: 'a' unreachable2
+    5             | /* empty */
+
+    6 unreachable2: /* empty */
+    7             | /* empty */
+
+    8 reported_conflicts: 'a'
+    9                   | 'a'
+   10                   | /* empty */
+
+
+Terminals, with rules where they appear
+
+$end (0) 0
+'a' (97) 1 2 4 8 9
+error (256)
+
+
+Nonterminals, with rules where they appear
+
+$accept (4)
+    on left: 0
+start (5)
+    on left: 1, on right: 0
+resolved_conflict (6)
+    on left: 2 3, on right: 1
+unreachable1 (7)
+    on left: 4 5, on right: 2
+unreachable2 (8)
+    on left: 6 7, on right: 4
+reported_conflicts (9)
+    on left: 8 9 10, on right: 1
+
+
+state 0
+
+    0 $accept: . start $end
+    1 start: . resolved_conflict 'a' reported_conflicts 'a'
+    2 resolved_conflict: . 'a' unreachable1
+    3                  | .  ['a']
+
+    $default  reduce using rule 3 (resolved_conflict)
+
+    start              go to state 1
+    resolved_conflict  go to state 2
+
+    Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
+
+
+state 1
+
+    0 $accept: start . $end
+
+    $end  shift, and go to state 3
+
+
+state 2
+
+    1 start: resolved_conflict . 'a' reported_conflicts 'a'
+
+    'a'  shift, and go to state 4
+
+
+state 3
+
+    0 $accept: start $end .
+
+    $default  accept
+
+
+state 4
+
+    1 start: resolved_conflict 'a' . reported_conflicts 'a'
+    8 reported_conflicts: . 'a'
+    9                   | . 'a'
+   10                   | .  ['a']
+
+    'a'  shift, and go to state 5
+
+    'a'  [reduce using rule 10 (reported_conflicts)]
+
+    reported_conflicts  go to state 6
+
+
+state 5
+
+    8 reported_conflicts: 'a' .  ['a']
+    9                   | 'a' .  ['a']
+
+    'a'       reduce using rule 8 (reported_conflicts)
+    'a'       [reduce using rule 9 (reported_conflicts)]
+    $default  reduce using rule 8 (reported_conflicts)
+
+
+state 6
+
+    1 start: resolved_conflict 'a' reported_conflicts . 'a'
+
+    'a'  shift, and go to state 7
+
+
+state 7
+
+    1 start: resolved_conflict 'a' reported_conflicts 'a' .
+
+    $default  reduce using rule 1 (start)
+]])
+
+AT_DATA([[input-keep.y]],
+[[%define lr.keep-unreachable-states
+]])
+AT_CHECK([[cat input.y >> input-keep.y]])
+
+AT_BISON_CHECK([[input-keep.y]], 0, [],
+[[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
+input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
+input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
+input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
+input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------ ##
+## Solved conflicts report for multiple reductions in a state.  ##
+## ------------------------------------------------------------ ##
+
+AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
+
+# Used to lose earlier solved conflict messages even within a single S/R/R.
+
+AT_DATA([[input.y]],
+[[%left 'a'
+%right 'b'
+%right 'c'
+%right 'd'
+%%
+start:
+    'a'
+  | empty_a 'a'
+  | 'b'
+  | empty_b 'b'
+  | 'c'
+  | empty_c1 'c'
+  | empty_c2 'c'
+  | empty_c3 'c'
+  ;
+empty_a: %prec 'a' ;
+empty_b: %prec 'b' ;
+empty_c1: %prec 'c' ;
+empty_c2: %prec 'c' ;
+empty_c3: %prec 'd' ;
+]])
+AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
+AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
+[[state 0
+
+    0 $accept: . start $end
+    1 start: . 'a'
+    2      | . empty_a 'a'
+    3      | . 'b'
+    4      | . empty_b 'b'
+    5      | . 'c'
+    6      | . empty_c1 'c'
+    7      | . empty_c2 'c'
+    8      | . empty_c3 'c'
+    9 empty_a: .  ['a']
+   10 empty_b: .  []
+   11 empty_c1: .  []
+   12 empty_c2: .  []
+   13 empty_c3: .  ['c']
+
+    'b'  shift, and go to state 1
+
+    'c'       reduce using rule 13 (empty_c3)
+    $default  reduce using rule 9 (empty_a)
+
+    start     go to state 2
+    empty_a   go to state 3
+    empty_b   go to state 4
+    empty_c1  go to state 5
+    empty_c2  go to state 6
+    empty_c3  go to state 7
+
+    Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
+    Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
+    Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
+    Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
+    Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
+
+
+state 1
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------ ##
+## %nonassoc error actions for multiple reductions in a state.  ##
+## ------------------------------------------------------------ ##
+
+# Used to abort when trying to resolve conflicts as %nonassoc error actions for
+# multiple reductions in a state.
+
+# For a %nonassoc error action token, used to print the first remaining
+# reduction on that token without brackets.
+
+AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
+
+AT_DATA([[input.y]],
+[[%nonassoc 'a' 'b' 'c'
+%%
+start:
+    'a'
+  | empty_a 'a'
+  | 'b'
+  | empty_b 'b'
+  | 'c'
+  | empty_c1 'c'
+  | empty_c2 'c'
+  | empty_c3 'c'
+  ;
+empty_a: %prec 'a' ;
+empty_b: %prec 'b' ;
+empty_c1: %prec 'c' ;
+empty_c2: %prec 'c' ;
+empty_c3: %prec 'c' ;
+]])
+
+AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
+AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
+[[state 0
+
+    0 $accept: . start $end
+    1 start: . 'a'
+    2      | . empty_a 'a'
+    3      | . 'b'
+    4      | . empty_b 'b'
+    5      | . 'c'
+    6      | . empty_c1 'c'
+    7      | . empty_c2 'c'
+    8      | . empty_c3 'c'
+    9 empty_a: .  []
+   10 empty_b: .  []
+   11 empty_c1: .  []
+   12 empty_c2: .  ['c']
+   13 empty_c3: .  ['c']
+
+    'a'  error (nonassociative)
+    'b'  error (nonassociative)
+    'c'  error (nonassociative)
+
+    'c'  [reduce using rule 12 (empty_c2)]
+    'c'  [reduce using rule 13 (empty_c3)]
+
+    start     go to state 1
+    empty_a   go to state 2
+    empty_b   go to state 3
+    empty_c1  go to state 4
+    empty_c2  go to state 5
+    empty_c3  go to state 6
+
+    Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
+    Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
+    Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
+
+
+state 1
+]])
+AT_CLEANUP
+
+
+## --------------------------------- ##
+## -W versus %expect and %expect-rr  ##
+## --------------------------------- ##
+
+AT_SETUP([[-W versus %expect and %expect-rr]])
+
+AT_DATA([[sr-rr.y]],
+[[%glr-parser
+%%
+start: 'a' | A 'a' | B 'a' ;
+A: ;
+B: ;
+]])
+AT_DATA([[sr.y]],
+[[%glr-parser
+%%
+start: 'a' | A 'a' ;
+A: ;
+]])
+AT_DATA([[rr.y]],
+[[%glr-parser
+%%
+start: A | B ;
+A: ;
+B: ;
+]])
+
+AT_BISON_CHECK([[sr-rr.y]], [[0]], [[]],
+[[sr-rr.y: conflicts: 1 shift/reduce, 1 reduce/reduce
+]])
+AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]],
+[[sr-rr.y: conflicts: 1 reduce/reduce
+]])
+AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]],
+[[sr-rr.y: conflicts: 1 shift/reduce
+]])
+
+[for gram in sr-rr sr rr; do
+  for sr_exp_i in '' 0 1 2; do
+    for rr_exp_i in '' 0 1 2; do
+      test -z "$sr_exp_i" && test -z "$rr_exp_i" && continue
+
+      # Build grammar file.
+      sr_exp=0
+      rr_exp=0
+      file=$gram
+      directives=
+      if test -n "$sr_exp_i"; then
+        sr_exp=$sr_exp_i
+        file=$file-expect-$sr_exp
+        directives="%expect $sr_exp"
+      fi
+      if test -n "$rr_exp_i"; then
+        rr_exp=$rr_exp_i
+        file=$file-expect-rr-$rr_exp
+        directives="$directives %expect-rr $rr_exp"
+      fi
+      file=$file.y
+      echo "$directives" > $file
+      cat $gram.y >> $file
+
+      # Count actual conflicts.
+      conflicts=
+      sr_count=0
+      rr_count=0
+      if test $gram = sr || test $gram = sr-rr; then
+        conflicts="1 shift/reduce"
+        sr_count=1
+      fi
+      if test $gram = rr || test $gram = sr-rr; then
+        if test -n "$conflicts"; then
+          conflicts="$conflicts, "
+        fi
+        conflicts="${conflicts}1 reduce/reduce"
+        rr_count=1
+      fi
+
+      # Run tests.
+      if test $sr_count -eq $sr_exp && test $rr_count -eq $rr_exp; then
+        ]AT_BISON_CHECK([[-Wnone $file]])[
+        ]AT_BISON_CHECK([[-Werror $file]])[
+      else
+        echo "$file: conflicts: $conflicts" > experr
+        if test $sr_count -ne $sr_exp; then
+          if test $sr_exp -ne 1; then s=s; else s= ; fi
+          echo "$file: expected $sr_exp shift/reduce conflict$s" >> experr
+        fi
+        if test $rr_count -ne $rr_exp; then
+          if test $rr_exp -ne 1; then s=s; else s= ; fi
+          echo "$file: expected $rr_exp reduce/reduce conflict$s" >> experr
+        fi
+        ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[
+        ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[
+      fi
+    done
+  done
+done]
+
+AT_CLEANUP