package: install README and the like in docdir

[bison.git] / tests / conflicts.at

diff --git a/tests/conflicts.at b/tests/conflicts.at
index c6671de7a73a73aca11d72e4bcfa7b4831de31e1..1ba94bcd3b8bb664cde62e54478d3316812c2225 100644 (file)
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -1,7 +1,6 @@
 # Exercising Bison on conflicts.                         -*- Autotest -*-
 
 # Exercising Bison on conflicts.                         -*- Autotest -*-
 

-# Copyright (C) 2002, 2003, 2004, 2005, 2007, 2009, 2010 Free
-# Software Foundation, Inc.
+# Copyright (C) 2002-2005, 2007-2013 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
 
 # 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


@@ -18,6 +17,248 @@
 
 AT_BANNER([[Conflicts.]])
 
 
 AT_BANNER([[Conflicts.]])
 

+## ------------------------- ##
+## Token declaration order.  ##
+## ------------------------- ##
+
+# This test checks that token are declared left to right when in a precedence
+# statement.
+
+AT_SETUP([Token declaration order])
+
+AT_BISON_OPTION_PUSHDEFS
+
+AT_DATA_GRAMMAR([[input.y]],
+[[%code {
+  #include <stdio.h>
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
+}
+%token A B C
+%token D
+%right E F G
+%right H I
+%right J
+%left  K
+%left  L M N
+%nonassoc O P Q
+%precedence R S T U
+%precedence V W
+%%
+exp: A
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE[
+int main (void)
+{
+  assert (A < B);
+  assert (B < C);
+  assert (C < D);
+  assert (D < E);
+  assert (E < F);
+  assert (F < G);
+  assert (G < H);
+  assert (H < I);
+  assert (I < J);
+  assert (J < K);
+  assert (K < L);
+  assert (L < M);
+  assert (M < N);
+  assert (N < O);
+  assert (O < P);
+  assert (P < Q);
+  assert (Q < R);
+  assert (R < S);
+  assert (S < T);
+  assert (T < U);
+  assert (U < V);
+  assert (V < W);
+  return 0;
+}
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+AT_COMPILE([input])
+
+AT_PARSER_CHECK([./input])
+
+AT_BISON_OPTION_POPDEFS
+
+AT_CLEANUP
+
+
+## --------------------------------------------------- ##
+## Token declaration order: literals vs. identifiers.  ##
+## --------------------------------------------------- ##
+
+# This test checks that when several tokens are declared by the same keyword,
+# some of them defined as a character ('a'), others as simple textual reference
+# (A), they are declared correctly left to right.
+# Previously, the following test would declare the states in the order 'o' 'p'
+# M N, instead of M N 'o' 'p'.
+
+AT_SETUP([Token declaration order: literals vs. identifiers])
+
+AT_DATA_GRAMMAR([[input.y]],
+[[%token 'a' 'b' C D
+%token E F 'g' 'h'
+%right 'i' 'j' K L
+%right M N 'o' 'p'
+%%
+exp: 'a'
+   | 'b'
+   | C
+   | D
+   | E
+   | F
+   | 'g'
+   | 'h'
+   | 'i'
+   | 'j'
+   | K
+   | L
+   | M
+   | N
+   | 'o'
+   | 'p'
+;
+%%
+]])
+
+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: . exp $end
+    1 exp: . 'a'
+    2    | . 'b'
+    3    | . C
+    4    | . D
+    5    | . E
+    6    | . F
+    7    | . 'g'
+    8    | . 'h'
+    9    | . 'i'
+   10    | . 'j'
+   11    | . K
+   12    | . L
+   13    | . M
+   14    | . N
+   15    | . 'o'
+   16    | . 'p'
+
+    'a'  shift, and go to state 1
+    'b'  shift, and go to state 2
+    C    shift, and go to state 3
+    D    shift, and go to state 4
+    E    shift, and go to state 5
+    F    shift, and go to state 6
+    'g'  shift, and go to state 7
+    'h'  shift, and go to state 8
+    'i'  shift, and go to state 9
+    'j'  shift, and go to state 10
+    K    shift, and go to state 11
+    L    shift, and go to state 12
+    M    shift, and go to state 13
+    N    shift, and go to state 14
+    'o'  shift, and go to state 15
+    'p'  shift, and go to state 16
+
+    exp  go to state 17
+
+
+State 1
+]])
+
+AT_CLEANUP
+
+
+## ------------------------------- ##
+## Useless associativity warning.  ##
+## ------------------------------- ##
+
+AT_SETUP([Useless associativity warning])
+
+AT_DATA([[input.y]],
+[[%token EQ "=" PL "+" ST "*"  LP "("
+%nonassoc "="
+%left "+"
+%left "*"
+%precedence "("
+%%
+stmt:
+  exp
+| "var" "=" exp
+;
+
+exp:
+  exp "+" exp
+| exp "*" "num"
+| "(" exp ")"
+| "num"
+;
+]])
+
+AT_BISON_CHECK([-Wprecedence input.y], 0, [],
+[[input.y:2.1-9: warning: useless precedence and associativity for "=" [-Wprecedence]
+input.y:4.1-5: warning: useless associativity for "*", use %precedence [-Wprecedence]
+input.y:5.1-11: warning: useless precedence for "(" [-Wprecedence]
+]])
+
+AT_CLEANUP
+
+
+## ---------------------------- ##
+## Useless precedence warning.  ##
+## ---------------------------- ##
+
+AT_SETUP([Useless precedence warning])
+
+AT_DATA([[input.y]],
+[[%token A B U V W X Y Z
+%precedence Z
+%left X
+%precedence Y
+%left W
+%right V
+%nonassoc U
+%%
+a: b
+ | a U b
+ | f
+;
+b: c
+ | b V c
+;
+c: d
+ | c W d
+;
+d: A
+ | d X d
+ | d Y A
+;
+f: B
+ | f Z B
+;
+]])
+
+AT_BISON_CHECK([-Wprecedence -fcaret -o input.c input.y], 0, [],
+[[input.y:7.1-9: warning: useless precedence and associativity for U [-Wprecedence]
+ %nonassoc U
+ ^^^^^^^^^
+input.y:6.1-6: warning: useless precedence and associativity for V [-Wprecedence]
+ %right V
+ ^^^^^^
+input.y:5.1-5: warning: useless precedence and associativity for W [-Wprecedence]
+ %left W
+ ^^^^^
+input.y:2.1-11: warning: useless precedence for Z [-Wprecedence]
+ %precedence Z
+ ^^^^^^^^^^^
+]])
+
+AT_CLEANUP
+

 
 ## ---------------- ##
 ## S/R in initial.  ##
 
 ## ---------------- ##
 ## S/R in initial.  ##


@@ -38,7 +279,13 @@ e: 'e' | /* Nothing. */;
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 0, [],
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 0, [],

-[[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
+[[input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
+]])
+
+AT_BISON_CHECK([-fcaret -o input.c input.y], 0, [],
+[[input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
+ e: 'e' | /* Nothing. */;
+         ^

 ]])
 
 AT_CLEANUP
 ]])
 
 AT_CLEANUP


@@ -50,20 +297,17 @@ AT_CLEANUP
 
 AT_SETUP([%nonassoc and eof])
 
 
 AT_SETUP([%nonassoc and eof])
 

+AT_BISON_OPTION_PUSHDEFS

 AT_DATA_GRAMMAR([input.y],
 [[
 %{
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 AT_DATA_GRAMMAR([input.y],
 [[
 %{
 #include <stdio.h>
 #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);
-}
-
+]AT_YYERROR_DEFINE[

 /* The current argument. */
 static const char *input;
 
 /* The current argument. */
 static const char *input;
 


@@ -71,8 +315,7 @@ static int
 yylex (void)
 {
   static size_t toknum;
 yylex (void)
 {
   static size_t toknum;

-  if (! (toknum <= strlen (input)))
-    abort ();
+  assert (toknum <= strlen (input));

   return input[toknum++];
 }
 
   return input[toknum++];
 }
 


@@ -93,134 +336,257 @@ main (int argc, const char *argv[])
   return yyparse ();
 }
 ]])
   return yyparse ();
 }
 ]])

+AT_BISON_OPTION_POPDEFS

 
 

-# Specify the output files to avoid problems on different file systems.
-AT_BISON_CHECK([-o input.c input.y])
+m4_pushdef([AT_NONASSOC_AND_EOF_CHECK],
+[AT_BISON_CHECK([$1[ -o input.c input.y]])

 AT_COMPILE([input])
 
 AT_COMPILE([input])
 

+m4_pushdef([AT_EXPECTING], [m4_if($2, [correct], [[, expecting $end]])])
+

 AT_PARSER_CHECK([./input '0<0'])
 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 AT_PARSER_CHECK([./input '0<0'])
 AT_PARSER_CHECK([./input '0<0<0'], [1], [],

-         [syntax error, unexpected '<'
+         [syntax error, unexpected '<'AT_EXPECTING

 ])
 
 AT_PARSER_CHECK([./input '0>0'])
 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 ])
 
 AT_PARSER_CHECK([./input '0>0'])
 AT_PARSER_CHECK([./input '0>0>0'], [1], [],

-         [syntax error, unexpected '>'
+         [syntax error, unexpected '>'AT_EXPECTING

 ])
 
 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 ])
 
 AT_PARSER_CHECK([./input '0<0>0'], [1], [],

-         [syntax error, unexpected '>'
+         [syntax error, unexpected '>'AT_EXPECTING

 ])
 
 ])
 

+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
 # We must disable default reductions in inconsistent states in order to

-# have an explicit list of all expected tokens.  (However, unless we use
-# canonical LR, lookahead sets are merged for different left contexts,
-# so it is still possible to have extra incorrect tokens in the expected
-# list.  That just doesn't happen to be a problem for this test case.)
+# have an explicit list of all expected tokens.
+AT_NONASSOC_AND_EOF_CHECK([[-Dlr.default-reduction=consistent]],
+                          [[correct]])
+
+# lr.default-reduction=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_BISON_CHECK([-Dlr.default-reductions=consistent -o input.c input.y])
-AT_COMPILE([input])
+AT_CLEANUP

 
 

-AT_PARSER_CHECK([./input '0<0'])
-AT_PARSER_CHECK([./input '0<0<0'], [1], [],
-         [syntax error, unexpected '<', expecting $end
-])

 
 

-AT_PARSER_CHECK([./input '0>0'])
-AT_PARSER_CHECK([./input '0>0>0'], [1], [],
-         [syntax error, unexpected '>', expecting $end
-])

 
 

-AT_PARSER_CHECK([./input '0<0>0'], [1], [],
-         [syntax error, unexpected '>', expecting $end
-])
+## ------------------------------------------- ##
+## parse.error=verbose and consistent errors.  ##
+## ------------------------------------------- ##

 
 

-AT_CLEANUP
+AT_SETUP([[parse.error=verbose and consistent errors]])

 
 

+m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [

 
 

+AT_BISON_OPTION_PUSHDEFS([$1])

 
 

-## -------------------------------------- ##
-## %error-verbose and consistent errors.  ##
-## -------------------------------------- ##
+m4_pushdef([AT_YYLEX_PROTOTYPE],
+[AT_SKEL_CC_IF([[int yylex (yy::parser::semantic_type *lvalp)]],
+               [[int yylex (YYSTYPE *lvalp)]])])

 
 

-AT_SETUP([[%error-verbose and consistent errors]])
+AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y],
+[AT_SKEL_JAVA_IF([[

 
 

-m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
+%code imports {
+  import java.io.IOException;
+}]], [[

 
 

-AT_DATA_GRAMMAR([input.y],
-[[%code {
+%code {]AT_SKEL_CC_IF([[
+  #include <string>]], [[

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

-  int yylex (void);
-  void yyerror (char const *);
+  ]AT_YYERROR_DECLARE])[
+  ]AT_YYLEX_PROTOTYPE[;

   #define USE(Var)
 }
 
   #define USE(Var)
 }
 

+]AT_SKEL_CC_IF([[%defines]], [[%define api.pure]])])[
+

 ]$1[
 
 ]$1[
 

-%error-verbose
+%define parse.error verbose

 
 %%
 
 ]$2[
 
 
 %%
 
 ]$2[
 

-%%
+]AT_SKEL_JAVA_IF([[%code lexer {]], [[%%]])[

 
 

-int
-yylex (void)
-{
-  static char const *input = "]$3[";
-  yylval = 1;
-  return *input++;
-}
+/*--------.
+| yylex.  |
+`--------*/]AT_SKEL_JAVA_IF([[

 
 

-void
-yyerror (char const *msg)
+public String input = "]$3[";
+public int index = 0;
+public int yylex ()

 {
 {

-  fprintf (stderr, "%s\n", msg);
+  if (index < input.length ())
+    return input.charAt (index++);
+  else
+    return 0;

 }
 }

+public Object getLVal ()
+{
+  return new Integer(1);
+}]], [[

 
 

-int
-main (void)
+]AT_YYLEX_PROTOTYPE[

 {
 {

-  return yyparse ();
-}
-]])
-AT_BISON_CHECK([[-o input.c input.y]])
-AT_COMPILE([[input]])
+  static char const *input = "]$3[";
+  *lvalp = 1;
+  return *input++;
+}]])[
+]AT_YYERROR_DEFINE[
+]AT_SKEL_JAVA_IF([[
+};
+
+%%]])[
+
+/*-------.
+| main.  |
+`-------*/
+]AT_MAIN_DEFINE
+])
+
+AT_FULL_COMPILE([[input]])

 
 m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']],
                                   $5, [a],  [[, expecting 'a']],
                                   $5, [b],  [[, expecting 'b']])])
 
 
 m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']],
                                   $5, [a],  [[, expecting 'a']],
                                   $5, [b],  [[, expecting 'b']])])
 

-AT_PARSER_CHECK([[./input]], [[1]], [[]],
+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])
 [[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],
+                           [[$end]], [[none]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %language "java"]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[end of input]], [[none]])
+
+# Even canonical LR doesn't foresee the error for 'a'!
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %define lr.default-reduction consistent]],
+                           [AT_PREVIOUS_STATE_GRAMMAR],
+                           [AT_PREVIOUS_STATE_INPUT],
+                           [[$end]], [[ab]])
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
+                             %define lr.default-reduction 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';
 
 m4_pushdef([AT_USER_ACTION_GRAMMAR],
 [[%nonassoc 'a';
 

-// If yylval=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 yylval=1.
+// 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';
 
 %destructor {
   if (!$$)
     fprintf (stderr, "Wrong destructor.\n");
 } 'a';
 

-// The lookahead assigned by the semantic action 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
+// 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
 // destructor that it selected according to the incorrect yytoken.  The
 // first error action would have reported an incorrect unexpected token

-// except that, due to another bug, the unexpected token is not reported
-// at all because the error action is the default action in a consistent
-// state.  That bug still needs to be fixed.
+// 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:
 start: error-reduce consistent-error 'a' { USE ($][3); } ;
 
 error-reduce:


@@ -247,20 +613,23 @@ start: 'b' consistent-error 'b' ;
 ]])
 m4_pushdef([AT_USER_ACTION_INPUT], [[aa]])
 
 ]])
 m4_pushdef([AT_USER_ACTION_INPUT], [[aa]])
 

-# See comments in grammar for why this test doesn't succeed.
-AT_XFAIL_IF([[:]])
-

 AT_CONSISTENT_ERRORS_CHECK([[]],
                            [AT_USER_ACTION_GRAMMAR],
                            [AT_USER_ACTION_INPUT],
                            [['b']], [[none]])
 AT_CONSISTENT_ERRORS_CHECK([[]],
                            [AT_USER_ACTION_GRAMMAR],
                            [AT_USER_ACTION_INPUT],
                            [['b']], [[none]])

-AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions consistent]],
+AT_CONSISTENT_ERRORS_CHECK([[%glr-parser]],
+                           [AT_USER_ACTION_GRAMMAR],
+                           [AT_USER_ACTION_INPUT],
+                           [['b']], [[none]])
+# No C++ or Java test because yychar cannot be manipulated by users.
+
+AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reduction consistent]],

                            [AT_USER_ACTION_GRAMMAR],
                            [AT_USER_ACTION_INPUT],
                            [['b']], [[none]])
 
 # Canonical LR doesn't foresee the error for 'a'!
                            [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_CONSISTENT_ERRORS_CHECK([[%define lr.default-reduction accepting]],

                            [AT_USER_ACTION_GRAMMAR],
                            [AT_USER_ACTION_INPUT],
                            [[$end]], [[a]])
                            [AT_USER_ACTION_GRAMMAR],
                            [AT_USER_ACTION_INPUT],
                            [[$end]], [[a]])


@@ -269,6 +638,16 @@ AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
                            [AT_USER_ACTION_INPUT],
                            [[$end]], [[a]])
 
                            [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-reduction 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_USER_ACTION_GRAMMAR])
 m4_popdef([AT_USER_ACTION_INPUT])
 


@@ -278,6 +657,98 @@ 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"])[
+]AT_MAIN_DEFINE
+])
+AT_BISON_OPTION_POPDEFS
+
+# Show canonical LR's failure.
+AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
+               [[0]], [[]],
+[[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+]])
+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: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+]])
+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: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+]])
+AT_COMPILE([[input]])
+AT_PARSER_CHECK([[./input]], [[1]], [[]],
+[[syntax error, unexpected 'a', expecting 'b' or 'c'
+]])
+
+AT_CLEANUP
+

 ## ------------------------- ##
 ## Unresolved SR Conflicts.  ##
 ## ------------------------- ##
 ## ------------------------- ##
 ## Unresolved SR Conflicts.  ##
 ## ------------------------- ##


@@ -293,8 +764,8 @@ exp: exp OP exp | NUM;
 ]])
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 ]])
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],

-[input.y: conflicts: 1 shift/reduce
-])
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+]])

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


@@ -325,7 +796,7 @@ exp (6)
     on left: 1 2, on right: 0 1
 
 
     on left: 1 2, on right: 0 1
 
 

-state 0
+State 0

 
     0 $accept: . exp $end
     1 exp: . exp OP exp
 
     0 $accept: . exp $end
     1 exp: . exp OP exp


@@ -336,14 +807,14 @@ state 0
     exp  go to state 2
 
 
     exp  go to state 2
 
 

-state 1
+State 1

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

-state 2
+State 2

 
     0 $accept: exp . $end
     1 exp: exp . OP exp
 
     0 $accept: exp . $end
     1 exp: exp . OP exp


@@ -352,14 +823,14 @@ state 2
     OP    shift, and go to state 4
 
 
     OP    shift, and go to state 4
 
 

-state 3
+State 3

 
     0 $accept: exp $end .
 
     $default  accept
 
 
 
     0 $accept: exp $end .
 
     $default  accept
 
 

-state 4
+State 4

 
     1 exp: . exp OP exp
     1    | exp OP . exp
 
     1 exp: . exp OP exp
     1    | exp OP . exp


@@ -370,7 +841,7 @@ state 4
     exp  go to state 5
 
 
     exp  go to state 5
 
 

-state 5
+State 5

 
     1 exp: exp . OP exp
     1    | exp OP exp .  [$end, OP]
 
     1 exp: exp . OP exp
     1    | exp OP exp .  [$end, OP]


@@ -428,7 +899,7 @@ exp (6)
     on left: 1 2, on right: 0 1
 
 
     on left: 1 2, on right: 0 1
 
 

-state 0
+State 0

 
     0 $accept: . exp $end
     1 exp: . exp OP exp
 
     0 $accept: . exp $end
     1 exp: . exp OP exp


@@ -439,14 +910,14 @@ state 0
     exp  go to state 2
 
 
     exp  go to state 2
 
 

-state 1
+State 1

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

-state 2
+State 2

 
     0 $accept: exp . $end
     1 exp: exp . OP exp
 
     0 $accept: exp . $end
     1 exp: exp . OP exp


@@ -455,14 +926,14 @@ state 2
     OP    shift, and go to state 4
 
 
     OP    shift, and go to state 4
 
 

-state 3
+State 3

 
     0 $accept: exp $end .
 
     $default  accept
 
 
 
     0 $accept: exp $end .
 
     $default  accept
 
 

-state 4
+State 4

 
     1 exp: . exp OP exp
     1    | exp OP . exp
 
     1 exp: . exp OP exp
     1    | exp OP . exp


@@ -473,7 +944,7 @@ state 4
     exp  go to state 5
 
 
     exp  go to state 5
 
 

-state 5
+State 5

 
     1 exp: exp . OP exp
     1    | exp OP exp .  [$end, OP]
 
     1 exp: exp . OP exp
     1    | exp OP exp .  [$end, OP]


@@ -486,6 +957,62 @@ state 5
 AT_CLEANUP
 
 
 AT_CLEANUP
 
 

+## ---------------------- ##
+## %precedence suffices.  ##
+## ---------------------- ##
+
+AT_SETUP([%precedence suffices])
+
+AT_DATA([input.y],
+[[%precedence "then"
+%precedence "else"
+%%
+stmt:
+  "if" cond "then" stmt
+| "if" cond "then" stmt "else" stmt
+| "stmt"
+;
+
+cond:
+  "exp"
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y])
+
+AT_CLEANUP
+
+
+## ------------------------------ ##
+## %precedence does not suffice.  ##
+## ------------------------------ ##
+
+AT_SETUP([%precedence does not suffice])
+
+AT_DATA([input.y],
+[[%precedence "then"
+%precedence "else"
+%%
+stmt:
+  "if" cond "then" stmt
+| "if" cond "then" stmt "else" stmt
+| "stmt"
+;
+
+cond:
+  "exp"
+| cond "then" cond
+;
+]])
+
+AT_BISON_CHECK([-o input.c input.y], 0, [],
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+input.y:12.3-18: warning: rule useless in parser due to conflicts [-Wother]
+]])
+
+AT_CLEANUP
+
+

 ## -------------------------------- ##
 ## Defaulted Conflicted Reduction.  ##
 ## -------------------------------- ##
 ## -------------------------------- ##
 ## Defaulted Conflicted Reduction.  ##
 ## -------------------------------- ##


@@ -496,13 +1023,13 @@ AT_CLEANUP
 #    $end           reduce using rule 3 (num)
 #    $end           [reduce using rule 4 (id)]
 #
 #    $end           reduce using rule 3 (num)
 #    $end           [reduce using rule 4 (id)]
 #

-# But when `reduce 3' is the default action, we'd produce:
+# 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
 #
 #    $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:
+# reduction), we make the 'reduce 3' explicit:

 #
 #    $end           reduce using rule 3 (num)
 #    $end           [reduce using rule 4 (id)]
 #
 #    $end           reduce using rule 3 (num)
 #    $end           [reduce using rule 4 (id)]


@@ -523,8 +1050,8 @@ id : '0';
 ]])
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 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'
+[[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y:4.6-8: warning: rule useless in parser due to conflicts [-Wother]

 ]])
 
 # Check the contents of the report.
 ]])
 
 # Check the contents of the report.


@@ -568,7 +1095,7 @@ id (7)
     on left: 4, on right: 2
 
 
     on left: 4, on right: 2
 
 

-state 0
+State 0

 
     0 $accept: . exp $end
     1 exp: . num
 
     0 $accept: . exp $end
     1 exp: . num


@@ -583,7 +1110,7 @@ state 0
     id   go to state 4
 
 
     id   go to state 4
 
 

-state 1
+State 1

 
     3 num: '0' .  [$end]
     4 id: '0' .  [$end]
 
     3 num: '0' .  [$end]
     4 id: '0' .  [$end]


@@ -593,28 +1120,28 @@ state 1
     $default  reduce using rule 3 (num)
 
 
     $default  reduce using rule 3 (num)
 
 

-state 2
+State 2

 
     0 $accept: exp . $end
 
     $end  shift, and go to state 5
 
 
 
     0 $accept: exp . $end
 
     $end  shift, and go to state 5
 
 

-state 3
+State 3

 
     1 exp: num .
 
     $default  reduce using rule 1 (exp)
 
 
 
     1 exp: num .
 
     $default  reduce using rule 1 (exp)
 
 

-state 4
+State 4

 
     2 exp: id .
 
     $default  reduce using rule 2 (exp)
 
 
 
     2 exp: id .
 
     $default  reduce using rule 2 (exp)
 
 

-state 5
+State 5

 
     0 $accept: exp $end .
 
 
     0 $accept: exp $end .
 


@@ -640,9 +1167,8 @@ exp: exp OP exp | NUM;
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],

-[input.y: conflicts: 1 shift/reduce
-input.y: expected 0 shift/reduce conflicts
-])
+[[input.y: error: shift/reduce conflicts: 1 found, 0 expected
+]])

 AT_CLEANUP
 
 
 AT_CLEANUP
 
 


@@ -677,9 +1203,8 @@ exp: exp OP exp | NUM;
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],

-[input.y: conflicts: 1 shift/reduce
-input.y: expected 2 shift/reduce conflicts
-])
+[[input.y: error: shift/reduce conflicts: 1 found, 2 expected
+]])

 AT_CLEANUP
 
 
 AT_CLEANUP
 
 


@@ -697,9 +1222,8 @@ a: 'a';
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],

-[input.y: conflicts: 1 reduce/reduce
-input.y: expected 0 reduce/reduce conflicts
-])
+[[input.y: error: reduce/reduce conflicts: 1 found, 0 expected
+]])

 AT_CLEANUP
 
 
 AT_CLEANUP
 
 


@@ -740,8 +1264,10 @@ e:   e '+' e
    ;
 ]])
 
    ;
 ]])
 

-AT_BISON_CHECK([-o input.c input.y], 0, [],
-[[input.y: conflicts: 4 shift/reduce
+AT_BISON_CHECK([-Wall -o input.c input.y], 0, [],
+[[input.y: warning: 4 shift/reduce conflicts [-Wconflicts-sr]
+input.y:1.1-5: warning: useless precedence and associativity for '+' [-Wprecedence]
+input.y:2.1-5: warning: useless precedence and associativity for '*' [-Wprecedence]

 ]])
 AT_CLEANUP
 
 ]])
 AT_CLEANUP
 


@@ -843,14 +1369,15 @@ reported_conflicts:
 ]])
 
 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 ]])
 
 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 */
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y:12.5-20: warning: rule useless in parser due to conflicts [-Wother]
+input.y:20.5-20: warning: rule useless in parser due to conflicts [-Wother]
+input.y:21.4: warning: rule useless in parser due to conflicts [-Wother]
+input.y:25.13: warning: rule useless in parser due to conflicts [-Wother]
+input.y:25.16: warning: rule useless in parser due to conflicts [-Wother]
+input.y:31.5-7: warning: rule useless in parser due to conflicts [-Wother]
+input.y:32.4: warning: rule useless in parser due to conflicts [-Wother]

 ]])
 
 AT_CHECK([[cat input.output]], 0,
 ]])
 
 AT_CHECK([[cat input.output]], 0,


@@ -859,13 +1386,13 @@ AT_CHECK([[cat input.output]], 0,
     2 resolved_conflict: 'a' unreachable1
 
     4 unreachable1: 'a' unreachable2
     2 resolved_conflict: 'a' unreachable1
 
     4 unreachable1: 'a' unreachable2

-    5             | /* empty */
+    5             | %empty

 
 

-    6 unreachable2: /* empty */
-    7             | /* empty */
+    6 unreachable2: %empty
+    7             | %empty

 
     9 reported_conflicts: 'a'
 
     9 reported_conflicts: 'a'

-   10                   | /* empty */
+   10                   | %empty

 
 
 State 4 conflicts: 1 shift/reduce
 
 
 State 4 conflicts: 1 shift/reduce


@@ -879,17 +1406,17 @@ Grammar
     1 start: resolved_conflict 'a' reported_conflicts 'a'
 
     2 resolved_conflict: 'a' unreachable1
     1 start: resolved_conflict 'a' reported_conflicts 'a'
 
     2 resolved_conflict: 'a' unreachable1

-    3                  | /* empty */
+    3                  | %empty

 
     4 unreachable1: 'a' unreachable2
 
     4 unreachable1: 'a' unreachable2

-    5             | /* empty */
+    5             | %empty

 
 

-    6 unreachable2: /* empty */
-    7             | /* empty */
+    6 unreachable2: %empty
+    7             | %empty

 
     8 reported_conflicts: 'a'
     9                   | 'a'
 
     8 reported_conflicts: 'a'
     9                   | 'a'

-   10                   | /* empty */
+   10                   | %empty

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


@@ -915,12 +1442,12 @@ reported_conflicts (9)
     on left: 8 9 10, on right: 1
 
 
     on left: 8 9 10, on right: 1
 
 

-state 0
+State 0

 
     0 $accept: . start $end
     1 start: . resolved_conflict 'a' reported_conflicts 'a'
     2 resolved_conflict: . 'a' unreachable1
 
     0 $accept: . start $end
     1 start: . resolved_conflict 'a' reported_conflicts 'a'
     2 resolved_conflict: . 'a' unreachable1

-    3                  | .  ['a']
+    3                  | . %empty  ['a']

 
     $default  reduce using rule 3 (resolved_conflict)
 
 
     $default  reduce using rule 3 (resolved_conflict)
 


@@ -930,33 +1457,33 @@ state 0
     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 
 
     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 
 

-state 1
+State 1

 
     0 $accept: start . $end
 
     $end  shift, and go to state 3
 
 
 
     0 $accept: start . $end
 
     $end  shift, and go to state 3
 
 

-state 2
+State 2

 
     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 
     'a'  shift, and go to state 4
 
 
 
     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 
     'a'  shift, and go to state 4
 
 

-state 3
+State 3

 
     0 $accept: start $end .
 
     $default  accept
 
 
 
     0 $accept: start $end .
 
     $default  accept
 
 

-state 4
+State 4

 
     1 start: resolved_conflict 'a' . reported_conflicts 'a'
     8 reported_conflicts: . 'a'
     9                   | . 'a'
 
     1 start: resolved_conflict 'a' . reported_conflicts 'a'
     8 reported_conflicts: . 'a'
     9                   | . 'a'

-   10                   | .  ['a']
+   10                   | . %empty  ['a']

 
     'a'  shift, and go to state 5
 
 
     'a'  shift, and go to state 5
 


@@ -965,7 +1492,7 @@ state 4
     reported_conflicts  go to state 6
 
 
     reported_conflicts  go to state 6
 
 

-state 5
+State 5

 
     8 reported_conflicts: 'a' .  ['a']
     9                   | 'a' .  ['a']
 
     8 reported_conflicts: 'a' .  ['a']
     9                   | 'a' .  ['a']


@@ -975,14 +1502,14 @@ state 5
     $default  reduce using rule 8 (reported_conflicts)
 
 
     $default  reduce using rule 8 (reported_conflicts)
 
 

-state 6
+State 6

 
     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 
     'a'  shift, and go to state 7
 
 
 
     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 
     'a'  shift, and go to state 7
 
 

-state 7
+State 7

 
     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 
 
     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 


@@ -990,16 +1517,17 @@ state 7
 ]])
 
 AT_DATA([[input-keep.y]],
 ]])
 
 AT_DATA([[input-keep.y]],

-[[%define lr.keep-unreachable-states
+[[%define lr.keep-unreachable-state

 ]])
 AT_CHECK([[cat input.y >> input-keep.y]])
 
 AT_BISON_CHECK([[input-keep.y]], 0, [],
 ]])
 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 */
+[[input-keep.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+input-keep.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+input-keep.y:22.4: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:26.16: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:32.5-7: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:33.4: warning: rule useless in parser due to conflicts [-Wother]

 ]])
 
 AT_CLEANUP
 ]])
 
 AT_CLEANUP


@@ -1036,8 +1564,8 @@ empty_c2: %prec 'c' ;
 empty_c3: %prec 'd' ;
 ]])
 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 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
+AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
+[[State 0

 
     0 $accept: . start $end
     1 start: . 'a'
 
     0 $accept: . start $end
     1 start: . 'a'


@@ -1048,14 +1576,14 @@ AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
     6      | . empty_c1 'c'
     7      | . empty_c2 'c'
     8      | . empty_c3 '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']
+    9 empty_a: . %empty  ['a']
+   10 empty_b: . %empty  []
+   11 empty_c1: . %empty  []
+   12 empty_c2: . %empty  []
+   13 empty_c3: . %empty  ['c']

 
     'b'  shift, and go to state 1
 
     'b'  shift, and go to state 1

- 
+

     'c'       reduce using rule 13 (empty_c3)
     $default  reduce using rule 9 (empty_a)
 
     'c'       reduce using rule 13 (empty_c3)
     $default  reduce using rule 9 (empty_a)
 


@@ -1073,7 +1601,7 @@ AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
 
 
     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
 
 

-state 1
+State 1

 ]])
 
 AT_CLEANUP
 ]])
 
 AT_CLEANUP


@@ -1112,8 +1640,8 @@ empty_c3: %prec 'c' ;
 ]])
 
 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 ]])
 
 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
+AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
+[[State 0

 
     0 $accept: . start $end
     1 start: . 'a'
 
     0 $accept: . start $end
     1 start: . 'a'


@@ -1124,11 +1652,11 @@ AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
     6      | . empty_c1 'c'
     7      | . empty_c2 'c'
     8      | . empty_c3 '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']
+    9 empty_a: . %empty  []
+   10 empty_b: . %empty  []
+   11 empty_c1: . %empty  []
+   12 empty_c2: . %empty  ['c']
+   13 empty_c3: . %empty  ['c']

 
     'a'  error (nonassociative)
     'b'  error (nonassociative)
 
     'a'  error (nonassociative)
     'b'  error (nonassociative)


@@ -1149,6 +1677,150 @@ AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
 
 
     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
 
 

-state 1
+State 1

 ]])
 AT_CLEANUP
 ]])
 AT_CLEANUP

+
+
+## -------------------- ##
+## %expect-rr non GLR.  ##
+## -------------------- ##
+
+AT_SETUP([[%expect-rr non GLR]])
+
+AT_DATA([[1.y]],
+[[%expect-rr 0
+%%
+exp: 'a'
+]])
+
+AT_BISON_CHECK([[1.y]], [[0]], [],
+[[1.y: warning: %expect-rr applies only to GLR parsers [-Wother]
+]])
+
+AT_DATA([[2.y]],
+[[%expect-rr 1
+%%
+exp: 'a' | 'a';
+]])
+
+AT_BISON_CHECK([[2.y]], [[0]], [],
+[[2.y: warning: %expect-rr applies only to GLR parsers [-Wother]
+2.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+2.y:3.12-14: warning: rule useless in parser due to conflicts [-Wother]
+]])
+
+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: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+sr-rr.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+]])
+AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]],
+[[sr-rr.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+]])
+AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]],
+[[sr-rr.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+]])
+
+[
+# This is piece of code is rather complex for a simple task: try every
+# combinaison of (0 or 1 real SR) x (0 or 1 real RR) x (don't %expect
+# or %expect 0, 1, or 2 SR) x (don't %expect-rr or %expect-rr 0, 1, or 2
+# RR).
+
+# Number and types of genuine conflicts in the grammar.
+for gram in sr-rr sr rr; do
+  # Number of expected s/r conflicts.
+  for sr_exp_i in '' 0 1 2; do
+    # Number of expected r/r conflicts.
+    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
+
+      # Number of found conflicts.
+      case $gram in
+        (sr)    sr_count=1; rr_count=0;;
+        (rr)    sr_count=0; rr_count=1;;
+        (sr-rr) sr_count=1; rr_count=1;;
+      esac
+
+      # Update number of expected conflicts: if %expect is given then
+      # %expect-rr defaults to 0, and vice-versa.  Leave empty if
+      # nothing expected.
+      case $sr_exp_i:$rr_exp_i in
+        ?:) rr_exp_i=0;;
+        :?) sr_exp_i=0;;
+      esac
+
+      # 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 $file]])[
+      else
+        {
+          if test -z "$sr_exp_i" && test "$sr_count" -ne 0; then
+            echo "warning: $sr_count shift/reduce conflicts"
+          elif test "$sr_exp_i" -ne "$sr_count"; then
+            echo "error: shift/reduce conflicts: $sr_count found, $sr_exp_i expected"
+          fi
+          if test -z "$rr_exp_i" && test "$rr_count" -ne 0; then
+            echo "warning: $rr_count reduce/reduce conflicts"
+          elif test "$rr_exp_i" -ne "$rr_count"; then
+            echo "error: reduce/reduce conflicts: $rr_count found, $rr_exp_i expected"
+          fi
+        } | sed -e "s/^/$file: /" > experr
+        ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[
+        ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[
+      fi
+    done
+  done
+done]
+
+AT_CLEANUP