tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002-2005, 2007, 2009-2012 Free Software Foundation,
   4 # Inc.
   5
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 AT_BANNER([[Conflicts.]])
  20
  21
  22 ## ---------------- ##
  23 ## S/R in initial.  ##
  24 ## ---------------- ##
  25
  26 # I once hacked Bison in such a way that it lost its reductions on the
  27 # initial state (because it was confusing it with the last state).  It
  28 # took me a while to strip down my failures to this simple case.  So
  29 # make sure it finds the s/r conflict below.
  30
  31 AT_SETUP([S/R in initial])
  32
  33 AT_DATA([[input.y]],
  34 [[%expect 1
  35 %%
  36 exp: e 'e';
  37 e: 'e' | /* Nothing. */;
  38 ]])
  39
  40 AT_BISON_CHECK([-o input.c input.y], 0, [],
  41 [[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
  42 ]])
  43
  44 AT_CLEANUP
  45
  46
  47 ## ------------------- ##
  48 ## %nonassoc and eof.  ##
  49 ## ------------------- ##
  50
  51 AT_SETUP([%nonassoc and eof])
  52
  53 AT_BISON_OPTION_PUSHDEFS
  54 AT_DATA_GRAMMAR([input.y],
  55 [[
  56 %{
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <assert.h>
  61
  62 #define YYERROR_VERBOSE 1
  63 ]AT_YYERROR_DEFINE[
  64 /* The current argument. */
  65 static const char *input;
  66
  67 static int
  68 yylex (void)
  69 {
  70   static size_t toknum;
  71   assert (toknum <= strlen (input));
  72   return input[toknum++];
  73 }
  74
  75 %}
  76
  77 %nonassoc '<' '>'
  78
  79 %%
  80 expr: expr '<' expr
  81     | expr '>' expr
  82     | '0'
  83     ;
  84 %%
  85 int
  86 main (int argc, const char *argv[])
  87 {
  88   input = argc <= 1 ? "" : argv[1];
  89   return yyparse ();
  90 }
  91 ]])
  92 AT_BISON_OPTION_POPDEFS
  93
  94 m4_pushdef([AT_NONASSOC_AND_EOF_CHECK],
  95 [AT_BISON_CHECK([$1[ -o input.c input.y]])
  96 AT_COMPILE([input])
  97
  98 m4_pushdef([AT_EXPECTING], [m4_if($2, [correct], [[, expecting $end]])])
  99
 100 AT_PARSER_CHECK([./input '0<0'])
 101 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 102          [syntax error, unexpected '<'AT_EXPECTING
 103 ])
 104
 105 AT_PARSER_CHECK([./input '0>0'])
 106 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 107          [syntax error, unexpected '>'AT_EXPECTING
 108 ])
 109
 110 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 111          [syntax error, unexpected '>'AT_EXPECTING
 112 ])
 113
 114 m4_popdef([AT_EXPECTING])])
 115
 116 # Expected token list is missing.
 117 AT_NONASSOC_AND_EOF_CHECK([], [[incorrect]])
 118
 119 # We must disable default reductions in inconsistent states in order to
 120 # have an explicit list of all expected tokens.
 121 AT_NONASSOC_AND_EOF_CHECK([[-Dlr.default-reductions=consistent]],
 122                           [[correct]])
 123
 124 # lr.default-reductions=consistent happens to work for this test case.
 125 # However, for other grammars, lookahead sets can be merged for
 126 # different left contexts, so it is still possible to have an incorrect
 127 # expected list.  Canonical LR is almost a general solution (that is, it
 128 # can fail only when %nonassoc is used), so make sure it gives the same
 129 # result as above.
 130 AT_NONASSOC_AND_EOF_CHECK([[-Dlr.type=canonical-lr]], [[correct]])
 131
 132 # parse.lac=full is a completely general solution that does not require
 133 # any of the above sacrifices.  Of course, it does not extend the
 134 # language-recognition power of LALR to (IE)LR, but it does ensure that
 135 # the reported list of expected tokens matches what the given parser
 136 # would have accepted in place of the unexpected token.
 137 AT_NONASSOC_AND_EOF_CHECK([[-Dparse.lac=full]], [[correct]])
 138
 139 m4_popdef([AT_NONASSOC_AND_EOF_CHECK])
 140
 141 AT_CLEANUP
 142
 143
 144
 145 ## -------------------------------------- ##
 146 ## %error-verbose and consistent errors.  ##
 147 ## -------------------------------------- ##
 148
 149 AT_SETUP([[%error-verbose and consistent errors]])
 150
 151 m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
 152
 153 AT_BISON_OPTION_PUSHDEFS([$1])
 154
 155 m4_pushdef([AT_YYLEX_PROTOTYPE],
 156 [AT_SKEL_CC_IF([[int yylex (yy::parser::semantic_type *lvalp)]],
 157                [[int yylex (YYSTYPE *lvalp)]])])
 158
 159 AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y],
 160 [AT_SKEL_JAVA_IF([[
 161
 162 %code imports {
 163   import java.io.IOException;
 164 }]], [[
 165
 166 %code {]AT_SKEL_CC_IF([[
 167   #include <cassert>
 168   #include <string>]], [[
 169   #include <assert.h>
 170   #include <stdio.h>
 171   ]AT_YYERROR_DECLARE])[
 172   ]AT_YYLEX_PROTOTYPE[;
 173   #define USE(Var)
 174 }
 175
 176 ]AT_SKEL_CC_IF([[%defines]], [[%define api.pure]])])[
 177
 178 ]$1[
 179
 180 %error-verbose
 181
 182 %%
 183
 184 ]$2[
 185
 186 ]AT_SKEL_JAVA_IF([[%code lexer {]], [[%%]])[
 187
 188 /*--------.
 189 | yylex.  |
 190 `--------*/]AT_SKEL_JAVA_IF([[
 191
 192 public String input = "]$3[";
 193 public int index = 0;
 194 public int yylex ()
 195 {
 196   if (index < input.length ())
 197     return input.charAt (index++);
 198   else
 199     return 0;
 200 }
 201 public Object getLVal ()
 202 {
 203   return new Integer(1);
 204 }]], [[
 205
 206 ]AT_YYLEX_PROTOTYPE[
 207 {
 208   static char const *input = "]$3[";
 209   *lvalp = 1;
 210   return *input++;
 211 }]])[
 212 ]AT_YYERROR_DEFINE[
 213 ]AT_SKEL_JAVA_IF([[
 214 };
 215
 216 %%]])[
 217
 218 /*-------.
 219 | main.  |
 220 `-------*/]AT_SKEL_JAVA_IF([[
 221
 222 class input
 223 {
 224   public static void main (String args[]) throws IOException
 225   {
 226     YYParser p = new YYParser ();
 227     p.parse ();
 228   }
 229 }]], [AT_SKEL_CC_IF([[
 230
 231 int
 232 main (void)
 233 {
 234   yy::parser parser;
 235   return parser.parse ();
 236 }]], [[
 237
 238 int
 239 main (void)
 240 {
 241   return yyparse ();
 242 }]])])[
 243 ]])
 244
 245 AT_FULL_COMPILE([[input]])
 246
 247 m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']],
 248                                   $5, [a],  [[, expecting 'a']],
 249                                   $5, [b],  [[, expecting 'b']])])
 250
 251 AT_SKEL_JAVA_IF([AT_JAVA_PARSER_CHECK([[input]], [[0]]],
 252                 [AT_PARSER_CHECK([[./input]], [[1]]]),
 253 [[]],
 254 [[syntax error, unexpected ]$4[]AT_EXPECTING[
 255 ]])
 256
 257 m4_popdef([AT_EXPECTING])
 258 m4_popdef([AT_YYLEX_PROTOTYPE])
 259 AT_BISON_OPTION_POPDEFS
 260
 261 ])
 262
 263 m4_pushdef([AT_PREVIOUS_STATE_GRAMMAR],
 264 [[%nonassoc 'a';
 265
 266 start: consistent-error-on-a-a 'a' ;
 267
 268 consistent-error-on-a-a:
 269     'a' default-reduction
 270   | 'a' default-reduction 'a'
 271   | 'a' shift
 272   ;
 273
 274 default-reduction: /*empty*/ ;
 275 shift: 'b' ;
 276
 277 // Provide another context in which all rules are useful so that this
 278 // test case looks a little more realistic.
 279 start: 'b' consistent-error-on-a-a 'c' ;
 280 ]])
 281
 282 m4_pushdef([AT_PREVIOUS_STATE_INPUT], [[a]])
 283
 284 # Unfortunately, no expected tokens are reported even though 'b' can be
 285 # accepted.  Nevertheless, the main point of this test is to make sure
 286 # that at least the unexpected token is reported.  In a previous version
 287 # of Bison, it wasn't reported because the error is detected in a
 288 # consistent state with an error action, and that case always triggered
 289 # the simple "syntax error" message.
 290 #
 291 # The point isn't to test IELR here, but state merging happens to
 292 # complicate this example.
 293 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr]],
 294                            [AT_PREVIOUS_STATE_GRAMMAR],
 295                            [AT_PREVIOUS_STATE_INPUT],
 296                            [[$end]], [[none]])
 297 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 298                              %glr-parser]],
 299                            [AT_PREVIOUS_STATE_GRAMMAR],
 300                            [AT_PREVIOUS_STATE_INPUT],
 301                            [[$end]], [[none]])
 302 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 303                              %language "c++"]],
 304                            [AT_PREVIOUS_STATE_GRAMMAR],
 305                            [AT_PREVIOUS_STATE_INPUT],
 306                            [[$end]], [[none]])
 307 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 308                              %language "java"]],
 309                            [AT_PREVIOUS_STATE_GRAMMAR],
 310                            [AT_PREVIOUS_STATE_INPUT],
 311                            [[end of input]], [[none]])
 312
 313 # Even canonical LR doesn't foresee the error for 'a'!
 314 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 315                              %define lr.default-reductions consistent]],
 316                            [AT_PREVIOUS_STATE_GRAMMAR],
 317                            [AT_PREVIOUS_STATE_INPUT],
 318                            [[$end]], [[ab]])
 319 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 320                              %define lr.default-reductions accepting]],
 321                            [AT_PREVIOUS_STATE_GRAMMAR],
 322                            [AT_PREVIOUS_STATE_INPUT],
 323                            [[$end]], [[ab]])
 324 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
 325                            [AT_PREVIOUS_STATE_GRAMMAR],
 326                            [AT_PREVIOUS_STATE_INPUT],
 327                            [[$end]], [[ab]])
 328
 329 # Only LAC gets it right.
 330 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr
 331                              %define parse.lac full]],
 332                            [AT_PREVIOUS_STATE_GRAMMAR],
 333                            [AT_PREVIOUS_STATE_INPUT],
 334                            [[$end]], [[b]])
 335 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
 336                              %define parse.lac full]],
 337                            [AT_PREVIOUS_STATE_GRAMMAR],
 338                            [AT_PREVIOUS_STATE_INPUT],
 339                            [[$end]], [[b]])
 340
 341 m4_popdef([AT_PREVIOUS_STATE_GRAMMAR])
 342 m4_popdef([AT_PREVIOUS_STATE_INPUT])
 343
 344 m4_pushdef([AT_USER_ACTION_GRAMMAR],
 345 [[%nonassoc 'a';
 346
 347 // If $$ = 0 here, then we know that the 'a' destructor is being invoked
 348 // incorrectly for the 'b' set in the semantic action below.  All 'a'
 349 // tokens are returned by yylex, which sets $$ = 1.
 350 %destructor {
 351   if (!$$)
 352     fprintf (stderr, "Wrong destructor.\n");
 353 } 'a';
 354
 355 // Rather than depend on an inconsistent state to induce reading a
 356 // lookahead as in the previous grammar, just assign the lookahead in a
 357 // semantic action.  That lookahead isn't needed before either error
 358 // action is encountered.  In a previous version of Bison, this was a
 359 // problem as it meant yychar was not translated into yytoken before
 360 // either error action.  The second error action thus invoked a
 361 // destructor that it selected according to the incorrect yytoken.  The
 362 // first error action would have reported an incorrect unexpected token
 363 // except that, due to the bug described in the previous grammar, the
 364 // unexpected token was not reported at all.
 365 start: error-reduce consistent-error 'a' { USE ($][3); } ;
 366
 367 error-reduce:
 368   'a' 'a' consistent-reduction consistent-error 'a'
 369   { USE (($][1, $][2, $][5)); }
 370 | 'a' error
 371   { USE ($][1); }
 372 ;
 373
 374 consistent-reduction: /*empty*/ {
 375   assert (yychar == ]AT_SKEL_CC_IF([[yyempty_]], [[YYEMPTY]])[);
 376   yylval = 0;
 377   yychar = 'b';
 378 } ;
 379
 380 consistent-error:
 381   'a' { USE ($][1); }
 382 | /*empty*/ %prec 'a'
 383 ;
 384
 385 // Provide another context in which all rules are useful so that this
 386 // test case looks a little more realistic.
 387 start: 'b' consistent-error 'b' ;
 388 ]])
 389 m4_pushdef([AT_USER_ACTION_INPUT], [[aa]])
 390
 391 AT_CONSISTENT_ERRORS_CHECK([[]],
 392                            [AT_USER_ACTION_GRAMMAR],
 393                            [AT_USER_ACTION_INPUT],
 394                            [['b']], [[none]])
 395 AT_CONSISTENT_ERRORS_CHECK([[%glr-parser]],
 396                            [AT_USER_ACTION_GRAMMAR],
 397                            [AT_USER_ACTION_INPUT],
 398                            [['b']], [[none]])
 399 AT_CONSISTENT_ERRORS_CHECK([[%language "c++"]],
 400                            [AT_USER_ACTION_GRAMMAR],
 401                            [AT_USER_ACTION_INPUT],
 402                            [['b']], [[none]])
 403 # No Java test because yychar cannot be manipulated by users.
 404
 405 AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions consistent]],
 406                            [AT_USER_ACTION_GRAMMAR],
 407                            [AT_USER_ACTION_INPUT],
 408                            [['b']], [[none]])
 409
 410 # Canonical LR doesn't foresee the error for 'a'!
 411 AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions accepting]],
 412                            [AT_USER_ACTION_GRAMMAR],
 413                            [AT_USER_ACTION_INPUT],
 414                            [[$end]], [[a]])
 415 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
 416                            [AT_USER_ACTION_GRAMMAR],
 417                            [AT_USER_ACTION_INPUT],
 418                            [[$end]], [[a]])
 419
 420 AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full]],
 421                            [AT_USER_ACTION_GRAMMAR],
 422                            [AT_USER_ACTION_INPUT],
 423                            [['b']], [[none]])
 424 AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full
 425                              %define lr.default-reductions accepting]],
 426                            [AT_USER_ACTION_GRAMMAR],
 427                            [AT_USER_ACTION_INPUT],
 428                            [[$end]], [[none]])
 429
 430 m4_popdef([AT_USER_ACTION_GRAMMAR])
 431 m4_popdef([AT_USER_ACTION_INPUT])
 432
 433 m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
 434
 435 AT_CLEANUP
 436
 437
 438
 439 ## ------------------------------------------------------- ##
 440 ## LAC: %nonassoc requires splitting canonical LR states.  ##
 441 ## ------------------------------------------------------- ##
 442
 443 # This test case demonstrates that, when %nonassoc is used, canonical
 444 # LR(1) parser table construction followed by conflict resolution
 445 # without further state splitting is not always sufficient to produce a
 446 # parser that can detect all syntax errors as soon as possible on one
 447 # token of lookahead.  However, LAC solves the problem completely even
 448 # with minimal LR parser tables.
 449
 450 AT_SETUP([[LAC: %nonassoc requires splitting canonical LR states]])
 451 AT_BISON_OPTION_PUSHDEFS
 452 AT_DATA_GRAMMAR([[input.y]],
 453 [[%code {
 454   #include <stdio.h>
 455   ]AT_YYERROR_DECLARE[
 456   ]AT_YYLEX_DECLARE[
 457 }
 458
 459 %error-verbose
 460 %nonassoc 'a'
 461
 462 %%
 463
 464 start:
 465   'a' problem 'a' // First context.
 466 | 'b' problem 'b' // Second context.
 467 | 'c' reduce-nonassoc // Just makes reduce-nonassoc useful.
 468 ;
 469
 470 problem:
 471   look reduce-nonassoc
 472 | look 'a'
 473 | look 'b'
 474 ;
 475
 476 // For the state reached after shifting the 'a' in these productions,
 477 // lookahead sets are the same in both the first and second contexts.
 478 // Thus, canonical LR reuses the same state for both contexts.  However,
 479 // the lookahead 'a' for the reduction "look: 'a'" later becomes an
 480 // error action only in the first context.  In order to immediately
 481 // detect the syntax error on 'a' here for only the first context, this
 482 // canonical LR state would have to be split into two states, and the
 483 // 'a' lookahead would have to be removed from only one of the states.
 484 look:
 485   'a' // Reduction lookahead set is always ['a', 'b'].
 486 | 'a' 'b'
 487 | 'a' 'c' // 'c' is forgotten as an expected token.
 488 ;
 489
 490 reduce-nonassoc: %prec 'a';
 491
 492 %%
 493 ]AT_YYERROR_DEFINE[
 494 ]AT_YYLEX_DEFINE(["aaa"])[
 495
 496 int
 497 main (void)
 498 {
 499   return yyparse ();
 500 }
 501 ]])
 502 AT_BISON_OPTION_POPDEFS
 503
 504 # Show canonical LR's failure.
 505 AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
 506                [[0]], [[]],
 507 [[input.y: conflicts: 2 shift/reduce
 508 ]])
 509 AT_COMPILE([[input]])
 510 AT_PARSER_CHECK([[./input]], [[1]], [[]],
 511 [[syntax error, unexpected 'a', expecting 'b'
 512 ]])
 513
 514 # It's corrected by LAC.
 515 AT_BISON_CHECK([[-Dlr.type=canonical-lr -Dparse.lac=full \
 516                  -o input.c input.y]], [[0]], [[]],
 517 [[input.y: conflicts: 2 shift/reduce
 518 ]])
 519 AT_COMPILE([[input]])
 520 AT_PARSER_CHECK([[./input]], [[1]], [[]],
 521 [[syntax error, unexpected 'a', expecting 'b' or 'c'
 522 ]])
 523
 524 # IELR is sufficient when LAC is used.
 525 AT_BISON_CHECK([[-Dlr.type=ielr -Dparse.lac=full -o input.c input.y]],
 526                [[0]], [[]],
 527 [[input.y: conflicts: 2 shift/reduce
 528 ]])
 529 AT_COMPILE([[input]])
 530 AT_PARSER_CHECK([[./input]], [[1]], [[]],
 531 [[syntax error, unexpected 'a', expecting 'b' or 'c'
 532 ]])
 533
 534 AT_CLEANUP
 535
 536 ## ------------------------- ##
 537 ## Unresolved SR Conflicts.  ##
 538 ## ------------------------- ##
 539
 540 AT_SETUP([Unresolved SR Conflicts])
 541
 542 AT_KEYWORDS([report])
 543
 544 AT_DATA([input.y],
 545 [[%token NUM OP
 546 %%
 547 exp: exp OP exp | NUM;
 548 ]])
 549
 550 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 551 [input.y: conflicts: 1 shift/reduce
 552 ])
 553
 554 # Check the contents of the report.
 555 AT_CHECK([cat input.output], [],
 556 [[State 5 conflicts: 1 shift/reduce
 557
 558
 559 Grammar
 560
 561     0 $accept: exp $end
 562
 563     1 exp: exp OP exp
 564     2    | NUM
 565
 566
 567 Terminals, with rules where they appear
 568
 569 $end (0) 0
 570 error (256)
 571 NUM (258) 2
 572 OP (259) 1
 573
 574
 575 Nonterminals, with rules where they appear
 576
 577 $accept (5)
 578     on left: 0
 579 exp (6)
 580     on left: 1 2, on right: 0 1
 581
 582
 583 State 0
 584
 585     0 $accept: . exp $end
 586     1 exp: . exp OP exp
 587     2    | . NUM
 588
 589     NUM  shift, and go to state 1
 590
 591     exp  go to state 2
 592
 593
 594 State 1
 595
 596     2 exp: NUM .
 597
 598     $default  reduce using rule 2 (exp)
 599
 600
 601 State 2
 602
 603     0 $accept: exp . $end
 604     1 exp: exp . OP exp
 605
 606     $end  shift, and go to state 3
 607     OP    shift, and go to state 4
 608
 609
 610 State 3
 611
 612     0 $accept: exp $end .
 613
 614     $default  accept
 615
 616
 617 State 4
 618
 619     1 exp: . exp OP exp
 620     1    | exp OP . exp
 621     2    | . NUM
 622
 623     NUM  shift, and go to state 1
 624
 625     exp  go to state 5
 626
 627
 628 State 5
 629
 630     1 exp: exp . OP exp
 631     1    | exp OP exp .  [$end, OP]
 632
 633     OP  shift, and go to state 4
 634
 635     OP        [reduce using rule 1 (exp)]
 636     $default  reduce using rule 1 (exp)
 637 ]])
 638
 639 AT_CLEANUP
 640
 641
 642
 643 ## ----------------------- ##
 644 ## Resolved SR Conflicts.  ##
 645 ## ----------------------- ##
 646
 647 AT_SETUP([Resolved SR Conflicts])
 648
 649 AT_KEYWORDS([report])
 650
 651 AT_DATA([input.y],
 652 [[%token NUM OP
 653 %left OP
 654 %%
 655 exp: exp OP exp | NUM;
 656 ]])
 657
 658 AT_BISON_CHECK([-o input.c --report=all input.y])
 659
 660 # Check the contents of the report.
 661 AT_CHECK([cat input.output], [],
 662 [[Grammar
 663
 664     0 $accept: exp $end
 665
 666     1 exp: exp OP exp
 667     2    | NUM
 668
 669
 670 Terminals, with rules where they appear
 671
 672 $end (0) 0
 673 error (256)
 674 NUM (258) 2
 675 OP (259) 1
 676
 677
 678 Nonterminals, with rules where they appear
 679
 680 $accept (5)
 681     on left: 0
 682 exp (6)
 683     on left: 1 2, on right: 0 1
 684
 685
 686 State 0
 687
 688     0 $accept: . exp $end
 689     1 exp: . exp OP exp
 690     2    | . NUM
 691
 692     NUM  shift, and go to state 1
 693
 694     exp  go to state 2
 695
 696
 697 State 1
 698
 699     2 exp: NUM .
 700
 701     $default  reduce using rule 2 (exp)
 702
 703
 704 State 2
 705
 706     0 $accept: exp . $end
 707     1 exp: exp . OP exp
 708
 709     $end  shift, and go to state 3
 710     OP    shift, and go to state 4
 711
 712
 713 State 3
 714
 715     0 $accept: exp $end .
 716
 717     $default  accept
 718
 719
 720 State 4
 721
 722     1 exp: . exp OP exp
 723     1    | exp OP . exp
 724     2    | . NUM
 725
 726     NUM  shift, and go to state 1
 727
 728     exp  go to state 5
 729
 730
 731 State 5
 732
 733     1 exp: exp . OP exp
 734     1    | exp OP exp .  [$end, OP]
 735
 736     $default  reduce using rule 1 (exp)
 737
 738     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 739 ]])
 740
 741 AT_CLEANUP
 742
 743
 744 ## -------------------------------- ##
 745 ## Defaulted Conflicted Reduction.  ##
 746 ## -------------------------------- ##
 747
 748 # When there are RR conflicts, some rules are disabled.  Usually it is
 749 # simply displayed as:
 750 #
 751 #    $end           reduce using rule 3 (num)
 752 #    $end           [reduce using rule 4 (id)]
 753 #
 754 # But when `reduce 3' is the default action, we'd produce:
 755 #
 756 #    $end           [reduce using rule 4 (id)]
 757 #    $default    reduce using rule 3 (num)
 758 #
 759 # In this precise case (a reduction is masked by the default
 760 # reduction), we make the `reduce 3' explicit:
 761 #
 762 #    $end           reduce using rule 3 (num)
 763 #    $end           [reduce using rule 4 (id)]
 764 #    $default    reduce using rule 3 (num)
 765 #
 766 # Maybe that's not the best display, but then, please propose something
 767 # else.
 768
 769 AT_SETUP([Defaulted Conflicted Reduction])
 770 AT_KEYWORDS([report])
 771
 772 AT_DATA([input.y],
 773 [[%%
 774 exp: num | id;
 775 num: '0';
 776 id : '0';
 777 %%
 778 ]])
 779
 780 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 781 [[input.y: conflicts: 1 reduce/reduce
 782 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
 783 ]])
 784
 785 # Check the contents of the report.
 786 AT_CHECK([cat input.output], [],
 787 [[Rules useless in parser due to conflicts
 788
 789     4 id: '0'
 790
 791
 792 State 1 conflicts: 1 reduce/reduce
 793
 794
 795 Grammar
 796
 797     0 $accept: exp $end
 798
 799     1 exp: num
 800     2    | id
 801
 802     3 num: '0'
 803
 804     4 id: '0'
 805
 806
 807 Terminals, with rules where they appear
 808
 809 $end (0) 0
 810 '0' (48) 3 4
 811 error (256)
 812
 813
 814 Nonterminals, with rules where they appear
 815
 816 $accept (4)
 817     on left: 0
 818 exp (5)
 819     on left: 1 2, on right: 0
 820 num (6)
 821     on left: 3, on right: 1
 822 id (7)
 823     on left: 4, on right: 2
 824
 825
 826 State 0
 827
 828     0 $accept: . exp $end
 829     1 exp: . num
 830     2    | . id
 831     3 num: . '0'
 832     4 id: . '0'
 833
 834     '0'  shift, and go to state 1
 835
 836     exp  go to state 2
 837     num  go to state 3
 838     id   go to state 4
 839
 840
 841 State 1
 842
 843     3 num: '0' .  [$end]
 844     4 id: '0' .  [$end]
 845
 846     $end      reduce using rule 3 (num)
 847     $end      [reduce using rule 4 (id)]
 848     $default  reduce using rule 3 (num)
 849
 850
 851 State 2
 852
 853     0 $accept: exp . $end
 854
 855     $end  shift, and go to state 5
 856
 857
 858 State 3
 859
 860     1 exp: num .
 861
 862     $default  reduce using rule 1 (exp)
 863
 864
 865 State 4
 866
 867     2 exp: id .
 868
 869     $default  reduce using rule 2 (exp)
 870
 871
 872 State 5
 873
 874     0 $accept: exp $end .
 875
 876     $default  accept
 877 ]])
 878
 879 AT_CLEANUP
 880
 881
 882
 883
 884 ## -------------------- ##
 885 ## %expect not enough.  ##
 886 ## -------------------- ##
 887
 888 AT_SETUP([%expect not enough])
 889
 890 AT_DATA([input.y],
 891 [[%token NUM OP
 892 %expect 0
 893 %%
 894 exp: exp OP exp | NUM;
 895 ]])
 896
 897 AT_BISON_CHECK([-o input.c input.y], 1, [],
 898 [input.y: conflicts: 1 shift/reduce
 899 input.y: error: expected 0 shift/reduce conflicts
 900 ])
 901 AT_CLEANUP
 902
 903
 904 ## --------------- ##
 905 ## %expect right.  ##
 906 ## --------------- ##
 907
 908 AT_SETUP([%expect right])
 909
 910 AT_DATA([input.y],
 911 [[%token NUM OP
 912 %expect 1
 913 %%
 914 exp: exp OP exp | NUM;
 915 ]])
 916
 917 AT_BISON_CHECK([-o input.c input.y])
 918 AT_CLEANUP
 919
 920
 921 ## ------------------ ##
 922 ## %expect too much.  ##
 923 ## ------------------ ##
 924
 925 AT_SETUP([%expect too much])
 926
 927 AT_DATA([input.y],
 928 [[%token NUM OP
 929 %expect 2
 930 %%
 931 exp: exp OP exp | NUM;
 932 ]])
 933
 934 AT_BISON_CHECK([-o input.c input.y], 1, [],
 935 [input.y: conflicts: 1 shift/reduce
 936 input.y: error: expected 2 shift/reduce conflicts
 937 ])
 938 AT_CLEANUP
 939
 940
 941 ## ------------------------------- ##
 942 ## %expect with reduce conflicts.  ##
 943 ## ------------------------------- ##
 944
 945 AT_SETUP([%expect with reduce conflicts])
 946
 947 AT_DATA([input.y],
 948 [[%expect 0
 949 %%
 950 program: a 'a' | a a;
 951 a: 'a';
 952 ]])
 953
 954 AT_BISON_CHECK([-o input.c input.y], 1, [],
 955 [input.y: conflicts: 1 reduce/reduce
 956 input.y: error: expected 0 reduce/reduce conflicts
 957 ])
 958 AT_CLEANUP
 959
 960
 961 ## ------------------------- ##
 962 ## %prec with user strings.  ##
 963 ## ------------------------- ##
 964
 965 AT_SETUP([%prec with user string])
 966
 967 AT_DATA([[input.y]],
 968 [[%%
 969 exp:
 970   "foo" %prec "foo"
 971 ;
 972 ]])
 973
 974 AT_BISON_CHECK([-o input.c input.y])
 975 AT_CLEANUP
 976
 977
 978 ## -------------------------------- ##
 979 ## %no-default-prec without %prec.  ##
 980 ## -------------------------------- ##
 981
 982 AT_SETUP([%no-default-prec without %prec])
 983
 984 AT_DATA([[input.y]],
 985 [[%left '+'
 986 %left '*'
 987
 988 %%
 989
 990 %no-default-prec;
 991
 992 e:   e '+' e
 993    | e '*' e
 994    | '0'
 995    ;
 996 ]])
 997
 998 AT_BISON_CHECK([-o input.c input.y], 0, [],
 999 [[input.y: conflicts: 4 shift/reduce
1000 ]])
1001 AT_CLEANUP
1002
1003
1004 ## ----------------------------- ##
1005 ## %no-default-prec with %prec.  ##
1006 ## ----------------------------- ##
1007
1008 AT_SETUP([%no-default-prec with %prec])
1009
1010 AT_DATA([[input.y]],
1011 [[%left '+'
1012 %left '*'
1013
1014 %%
1015
1016 %no-default-prec;
1017
1018 e:   e '+' e %prec '+'
1019    | e '*' e %prec '*'
1020    | '0'
1021    ;
1022 ]])
1023
1024 AT_BISON_CHECK([-o input.c input.y])
1025 AT_CLEANUP
1026
1027
1028 ## --------------- ##
1029 ## %default-prec.  ##
1030 ## --------------- ##
1031
1032 AT_SETUP([%default-prec])
1033
1034 AT_DATA([[input.y]],
1035 [[%left '+'
1036 %left '*'
1037
1038 %%
1039
1040 %default-prec;
1041
1042 e:   e '+' e
1043    | e '*' e
1044    | '0'
1045    ;
1046 ]])
1047
1048 AT_BISON_CHECK([-o input.c input.y])
1049 AT_CLEANUP
1050
1051
1052 ## ---------------------------------------------- ##
1053 ## Unreachable States After Conflict Resolution.  ##
1054 ## ---------------------------------------------- ##
1055
1056 AT_SETUP([[Unreachable States After Conflict Resolution]])
1057
1058 # If conflict resolution makes states unreachable, remove those states, report
1059 # rules that are then unused, and don't report conflicts in those states.  Test
1060 # what happens when a nonterminal becomes useless as a result of state removal
1061 # since that causes lalr.o's goto map to be rewritten.
1062
1063 AT_DATA([[input.y]],
1064 [[%output "input.c"
1065 %left 'a'
1066
1067 %%
1068
1069 start: resolved_conflict 'a' reported_conflicts 'a' ;
1070
1071 /* S/R conflict resolved as reduce, so the state with item
1072  * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
1073  * unreachable, and the associated production is useless.  */
1074 resolved_conflict:
1075     'a' unreachable1
1076   | %prec 'a'
1077   ;
1078
1079 /* S/R conflict that need not be reported since it is unreachable because of
1080  * the previous conflict resolution.  Nonterminal unreachable1 and all its
1081  * productions are useless.  */
1082 unreachable1:
1083     'a' unreachable2
1084   |
1085   ;
1086
1087 /* Likewise for a R/R conflict and nonterminal unreachable2.  */
1088 unreachable2: | ;
1089
1090 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
1091  * when their states are renumbered due to state removal.  */
1092 reported_conflicts:
1093     'a'
1094   | 'a'
1095   |
1096   ;
1097
1098 ]])
1099
1100 AT_BISON_CHECK([[--report=all input.y]], 0, [],
1101 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
1102 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
1103 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
1104 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
1105 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1106 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1107 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
1108 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
1109 ]])
1110
1111 AT_CHECK([[cat input.output]], 0,
1112 [[Rules useless in parser due to conflicts
1113
1114     2 resolved_conflict: 'a' unreachable1
1115
1116     4 unreachable1: 'a' unreachable2
1117     5             | /* empty */
1118
1119     6 unreachable2: /* empty */
1120     7             | /* empty */
1121
1122     9 reported_conflicts: 'a'
1123    10                   | /* empty */
1124
1125
1126 State 4 conflicts: 1 shift/reduce
1127 State 5 conflicts: 1 reduce/reduce
1128
1129
1130 Grammar
1131
1132     0 $accept: start $end
1133
1134     1 start: resolved_conflict 'a' reported_conflicts 'a'
1135
1136     2 resolved_conflict: 'a' unreachable1
1137     3                  | /* empty */
1138
1139     4 unreachable1: 'a' unreachable2
1140     5             | /* empty */
1141
1142     6 unreachable2: /* empty */
1143     7             | /* empty */
1144
1145     8 reported_conflicts: 'a'
1146     9                   | 'a'
1147    10                   | /* empty */
1148
1149
1150 Terminals, with rules where they appear
1151
1152 $end (0) 0
1153 'a' (97) 1 2 4 8 9
1154 error (256)
1155
1156
1157 Nonterminals, with rules where they appear
1158
1159 $accept (4)
1160     on left: 0
1161 start (5)
1162     on left: 1, on right: 0
1163 resolved_conflict (6)
1164     on left: 2 3, on right: 1
1165 unreachable1 (7)
1166     on left: 4 5, on right: 2
1167 unreachable2 (8)
1168     on left: 6 7, on right: 4
1169 reported_conflicts (9)
1170     on left: 8 9 10, on right: 1
1171
1172
1173 State 0
1174
1175     0 $accept: . start $end
1176     1 start: . resolved_conflict 'a' reported_conflicts 'a'
1177     2 resolved_conflict: . 'a' unreachable1
1178     3                  | .  ['a']
1179
1180     $default  reduce using rule 3 (resolved_conflict)
1181
1182     start              go to state 1
1183     resolved_conflict  go to state 2
1184
1185     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
1186
1187
1188 State 1
1189
1190     0 $accept: start . $end
1191
1192     $end  shift, and go to state 3
1193
1194
1195 State 2
1196
1197     1 start: resolved_conflict . 'a' reported_conflicts 'a'
1198
1199     'a'  shift, and go to state 4
1200
1201
1202 State 3
1203
1204     0 $accept: start $end .
1205
1206     $default  accept
1207
1208
1209 State 4
1210
1211     1 start: resolved_conflict 'a' . reported_conflicts 'a'
1212     8 reported_conflicts: . 'a'
1213     9                   | . 'a'
1214    10                   | .  ['a']
1215
1216     'a'  shift, and go to state 5
1217
1218     'a'  [reduce using rule 10 (reported_conflicts)]
1219
1220     reported_conflicts  go to state 6
1221
1222
1223 State 5
1224
1225     8 reported_conflicts: 'a' .  ['a']
1226     9                   | 'a' .  ['a']
1227
1228     'a'       reduce using rule 8 (reported_conflicts)
1229     'a'       [reduce using rule 9 (reported_conflicts)]
1230     $default  reduce using rule 8 (reported_conflicts)
1231
1232
1233 State 6
1234
1235     1 start: resolved_conflict 'a' reported_conflicts . 'a'
1236
1237     'a'  shift, and go to state 7
1238
1239
1240 State 7
1241
1242     1 start: resolved_conflict 'a' reported_conflicts 'a' .
1243
1244     $default  reduce using rule 1 (start)
1245 ]])
1246
1247 AT_DATA([[input-keep.y]],
1248 [[%define lr.keep-unreachable-states
1249 ]])
1250 AT_CHECK([[cat input.y >> input-keep.y]])
1251
1252 AT_BISON_CHECK([[input-keep.y]], 0, [],
1253 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
1254 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
1255 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1256 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
1257 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
1258 ]])
1259
1260 AT_CLEANUP
1261
1262
1263 ## ------------------------------------------------------------ ##
1264 ## Solved conflicts report for multiple reductions in a state.  ##
1265 ## ------------------------------------------------------------ ##
1266
1267 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
1268
1269 # Used to lose earlier solved conflict messages even within a single S/R/R.
1270
1271 AT_DATA([[input.y]],
1272 [[%left 'a'
1273 %right 'b'
1274 %right 'c'
1275 %right 'd'
1276 %%
1277 start:
1278     'a'
1279   | empty_a 'a'
1280   | 'b'
1281   | empty_b 'b'
1282   | 'c'
1283   | empty_c1 'c'
1284   | empty_c2 'c'
1285   | empty_c3 'c'
1286   ;
1287 empty_a: %prec 'a' ;
1288 empty_b: %prec 'b' ;
1289 empty_c1: %prec 'c' ;
1290 empty_c2: %prec 'c' ;
1291 empty_c3: %prec 'd' ;
1292 ]])
1293 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1294 AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
1295 [[State 0
1296
1297     0 $accept: . start $end
1298     1 start: . 'a'
1299     2      | . empty_a 'a'
1300     3      | . 'b'
1301     4      | . empty_b 'b'
1302     5      | . 'c'
1303     6      | . empty_c1 'c'
1304     7      | . empty_c2 'c'
1305     8      | . empty_c3 'c'
1306     9 empty_a: .  ['a']
1307    10 empty_b: .  []
1308    11 empty_c1: .  []
1309    12 empty_c2: .  []
1310    13 empty_c3: .  ['c']
1311
1312     'b'  shift, and go to state 1
1313
1314     'c'       reduce using rule 13 (empty_c3)
1315     $default  reduce using rule 9 (empty_a)
1316
1317     start     go to state 2
1318     empty_a   go to state 3
1319     empty_b   go to state 4
1320     empty_c1  go to state 5
1321     empty_c2  go to state 6
1322     empty_c3  go to state 7
1323
1324     Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
1325     Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
1326     Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
1327     Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
1328     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
1329
1330
1331 State 1
1332 ]])
1333
1334 AT_CLEANUP
1335
1336
1337 ## ------------------------------------------------------------ ##
1338 ## %nonassoc error actions for multiple reductions in a state.  ##
1339 ## ------------------------------------------------------------ ##
1340
1341 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
1342 # multiple reductions in a state.
1343
1344 # For a %nonassoc error action token, used to print the first remaining
1345 # reduction on that token without brackets.
1346
1347 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
1348
1349 AT_DATA([[input.y]],
1350 [[%nonassoc 'a' 'b' 'c'
1351 %%
1352 start:
1353     'a'
1354   | empty_a 'a'
1355   | 'b'
1356   | empty_b 'b'
1357   | 'c'
1358   | empty_c1 'c'
1359   | empty_c2 'c'
1360   | empty_c3 'c'
1361   ;
1362 empty_a: %prec 'a' ;
1363 empty_b: %prec 'b' ;
1364 empty_c1: %prec 'c' ;
1365 empty_c2: %prec 'c' ;
1366 empty_c3: %prec 'c' ;
1367 ]])
1368
1369 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1370 AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
1371 [[State 0
1372
1373     0 $accept: . start $end
1374     1 start: . 'a'
1375     2      | . empty_a 'a'
1376     3      | . 'b'
1377     4      | . empty_b 'b'
1378     5      | . 'c'
1379     6      | . empty_c1 'c'
1380     7      | . empty_c2 'c'
1381     8      | . empty_c3 'c'
1382     9 empty_a: .  []
1383    10 empty_b: .  []
1384    11 empty_c1: .  []
1385    12 empty_c2: .  ['c']
1386    13 empty_c3: .  ['c']
1387
1388     'a'  error (nonassociative)
1389     'b'  error (nonassociative)
1390     'c'  error (nonassociative)
1391
1392     'c'  [reduce using rule 12 (empty_c2)]
1393     'c'  [reduce using rule 13 (empty_c3)]
1394
1395     start     go to state 1
1396     empty_a   go to state 2
1397     empty_b   go to state 3
1398     empty_c1  go to state 4
1399     empty_c2  go to state 5
1400     empty_c3  go to state 6
1401
1402     Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1403     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1404     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1405
1406
1407 State 1
1408 ]])
1409 AT_CLEANUP
1410
1411
1412 ## --------------------------------- ##
1413 ## -W versus %expect and %expect-rr  ##
1414 ## --------------------------------- ##
1415
1416 AT_SETUP([[-W versus %expect and %expect-rr]])
1417
1418 AT_DATA([[sr-rr.y]],
1419 [[%glr-parser
1420 %%
1421 start: 'a' | A 'a' | B 'a' ;
1422 A: ;
1423 B: ;
1424 ]])
1425 AT_DATA([[sr.y]],
1426 [[%glr-parser
1427 %%
1428 start: 'a' | A 'a' ;
1429 A: ;
1430 ]])
1431 AT_DATA([[rr.y]],
1432 [[%glr-parser
1433 %%
1434 start: A | B ;
1435 A: ;
1436 B: ;
1437 ]])
1438
1439 AT_BISON_CHECK([[sr-rr.y]], [[0]], [[]],
1440 [[sr-rr.y: conflicts: 1 shift/reduce, 1 reduce/reduce
1441 ]])
1442 AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]],
1443 [[sr-rr.y: conflicts: 1 reduce/reduce
1444 ]])
1445 AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]],
1446 [[sr-rr.y: conflicts: 1 shift/reduce
1447 ]])
1448
1449 [for gram in sr-rr sr rr; do
1450   for sr_exp_i in '' 0 1 2; do
1451     for rr_exp_i in '' 0 1 2; do
1452       test -z "$sr_exp_i" && test -z "$rr_exp_i" && continue
1453
1454       # Build grammar file.
1455       sr_exp=0
1456       rr_exp=0
1457       file=$gram
1458       directives=
1459       if test -n "$sr_exp_i"; then
1460         sr_exp=$sr_exp_i
1461         file=$file-expect-$sr_exp
1462         directives="%expect $sr_exp"
1463       fi
1464       if test -n "$rr_exp_i"; then
1465         rr_exp=$rr_exp_i
1466         file=$file-expect-rr-$rr_exp
1467         directives="$directives %expect-rr $rr_exp"
1468       fi
1469       file=$file.y
1470       echo "$directives" > $file
1471       cat $gram.y >> $file
1472
1473       # Count actual conflicts.
1474       conflicts=
1475       sr_count=0
1476       rr_count=0
1477       if test $gram = sr || test $gram = sr-rr; then
1478         conflicts="1 shift/reduce"
1479         sr_count=1
1480       fi
1481       if test $gram = rr || test $gram = sr-rr; then
1482         if test -n "$conflicts"; then
1483           conflicts="$conflicts, "
1484         fi
1485         conflicts="${conflicts}1 reduce/reduce"
1486         rr_count=1
1487       fi
1488
1489       # Run tests.
1490       if test $sr_count -eq $sr_exp && test $rr_count -eq $rr_exp; then
1491         ]AT_BISON_CHECK([[-Wnone $file]])[
1492         ]AT_BISON_CHECK([[-Werror $file]])[
1493       else
1494         echo "$file: conflicts: $conflicts" > experr
1495         if test $sr_count -ne $sr_exp; then
1496           if test $sr_exp -ne 1; then s=s; else s= ; fi
1497           echo "$file: error: expected $sr_exp shift/reduce conflict$s" >> experr
1498         fi
1499         if test $rr_count -ne $rr_exp; then
1500           if test $rr_exp -ne 1; then s=s; else s= ; fi
1501           echo "$file: error: expected $rr_exp reduce/reduce conflict$s" >> experr
1502         fi
1503         ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[
1504         ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[
1505       fi
1506     done
1507   done
1508 done]
1509
1510 AT_CLEANUP