tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
   4
   5 # This program is free software: you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation, either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 AT_BANNER([[Conflicts.]])
  19
  20
  21 ## ---------------- ##
  22 ## S/R in initial.  ##
  23 ## ---------------- ##
  24
  25 # I once hacked Bison in such a way that it lost its reductions on the
  26 # initial state (because it was confusing it with the last state).  It
  27 # took me a while to strip down my failures to this simple case.  So
  28 # make sure it finds the s/r conflict below.
  29
  30 AT_SETUP([S/R in initial])
  31
  32 AT_DATA([[input.y]],
  33 [[%expect 1
  34 %%
  35 exp: e 'e';
  36 e: 'e' | /* Nothing. */;
  37 ]])
  38
  39 AT_BISON_CHECK([-o input.c input.y], 0, [],
  40 [[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
  41 ]])
  42
  43 AT_CLEANUP
  44
  45
  46 ## ------------------- ##
  47 ## %nonassoc and eof.  ##
  48 ## ------------------- ##
  49
  50 AT_SETUP([%nonassoc and eof])
  51
  52 AT_DATA_GRAMMAR([input.y],
  53 [[
  54 %{
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58
  59 #define YYERROR_VERBOSE 1
  60 static void
  61 yyerror (const char *msg)
  62 {
  63   fprintf (stderr, "%s\n", msg);
  64 }
  65
  66 /* The current argument. */
  67 static const char *input;
  68
  69 static int
  70 yylex (void)
  71 {
  72   static size_t toknum;
  73   if (! (toknum <= strlen (input)))
  74     abort ();
  75   return input[toknum++];
  76 }
  77
  78 %}
  79
  80 %nonassoc '<' '>'
  81
  82 %%
  83 expr: expr '<' expr
  84     | expr '>' expr
  85     | '0'
  86     ;
  87 %%
  88 int
  89 main (int argc, const char *argv[])
  90 {
  91   input = argc <= 1 ? "" : argv[1];
  92   return yyparse ();
  93 }
  94 ]])
  95
  96 # Specify the output files to avoid problems on different file systems.
  97 AT_BISON_CHECK([-o input.c input.y])
  98 AT_COMPILE([input])
  99
 100 AT_PARSER_CHECK([./input '0<0'])
 101 # FIXME: This is an actual bug, but a new one, in the sense that
 102 # no one has ever spotted it!  The messages are *wrong*: there should
 103 # be nothing there, it should be expected eof.
 104 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 105          [syntax error, unexpected '<', expecting '<' or '>'
 106 ])
 107
 108 AT_PARSER_CHECK([./input '0>0'])
 109 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 110          [syntax error, unexpected '>', expecting '<' or '>'
 111 ])
 112
 113 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 114          [syntax error, unexpected '>', expecting '<' or '>'
 115 ])
 116
 117 AT_CLEANUP
 118
 119
 120
 121 ## ------------------------- ##
 122 ## Unresolved SR Conflicts.  ##
 123 ## ------------------------- ##
 124
 125 AT_SETUP([Unresolved SR Conflicts])
 126
 127 AT_KEYWORDS([report])
 128
 129 AT_DATA([input.y],
 130 [[%token NUM OP
 131 %%
 132 exp: exp OP exp | NUM;
 133 ]])
 134
 135 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 136 [input.y: conflicts: 1 shift/reduce
 137 ])
 138
 139 # Check the contents of the report.
 140 AT_CHECK([cat input.output], [],
 141 [[State 5 conflicts: 1 shift/reduce
 142
 143
 144 Grammar
 145
 146     0 $accept: exp $end
 147
 148     1 exp: exp OP exp
 149     2    | NUM
 150
 151
 152 Terminals, with rules where they appear
 153
 154 $end (0) 0
 155 error (256)
 156 NUM (258) 2
 157 OP (259) 1
 158
 159
 160 Nonterminals, with rules where they appear
 161
 162 $accept (5)
 163     on left: 0
 164 exp (6)
 165     on left: 1 2, on right: 0 1
 166
 167
 168 state 0
 169
 170     0 $accept: . exp $end
 171     1 exp: . exp OP exp
 172     2    | . NUM
 173
 174     NUM  shift, and go to state 1
 175
 176     exp  go to state 2
 177
 178
 179 state 1
 180
 181     2 exp: NUM .
 182
 183     $default  reduce using rule 2 (exp)
 184
 185
 186 state 2
 187
 188     0 $accept: exp . $end
 189     1 exp: exp . OP exp
 190
 191     $end  shift, and go to state 3
 192     OP    shift, and go to state 4
 193
 194
 195 state 3
 196
 197     0 $accept: exp $end .
 198
 199     $default  accept
 200
 201
 202 state 4
 203
 204     1 exp: . exp OP exp
 205     1    | exp OP . exp
 206     2    | . NUM
 207
 208     NUM  shift, and go to state 1
 209
 210     exp  go to state 5
 211
 212
 213 state 5
 214
 215     1 exp: exp . OP exp
 216     1    | exp OP exp .  [$end, OP]
 217
 218     OP  shift, and go to state 4
 219
 220     OP        [reduce using rule 1 (exp)]
 221     $default  reduce using rule 1 (exp)
 222 ]])
 223
 224 AT_CLEANUP
 225
 226
 227
 228 ## ----------------------- ##
 229 ## Resolved SR Conflicts.  ##
 230 ## ----------------------- ##
 231
 232 AT_SETUP([Resolved SR Conflicts])
 233
 234 AT_KEYWORDS([report])
 235
 236 AT_DATA([input.y],
 237 [[%token NUM OP
 238 %left OP
 239 %%
 240 exp: exp OP exp | NUM;
 241 ]])
 242
 243 AT_BISON_CHECK([-o input.c --report=all input.y])
 244
 245 # Check the contents of the report.
 246 AT_CHECK([cat input.output], [],
 247 [[Grammar
 248
 249     0 $accept: exp $end
 250
 251     1 exp: exp OP exp
 252     2    | NUM
 253
 254
 255 Terminals, with rules where they appear
 256
 257 $end (0) 0
 258 error (256)
 259 NUM (258) 2
 260 OP (259) 1
 261
 262
 263 Nonterminals, with rules where they appear
 264
 265 $accept (5)
 266     on left: 0
 267 exp (6)
 268     on left: 1 2, on right: 0 1
 269
 270
 271 state 0
 272
 273     0 $accept: . exp $end
 274     1 exp: . exp OP exp
 275     2    | . NUM
 276
 277     NUM  shift, and go to state 1
 278
 279     exp  go to state 2
 280
 281
 282 state 1
 283
 284     2 exp: NUM .
 285
 286     $default  reduce using rule 2 (exp)
 287
 288
 289 state 2
 290
 291     0 $accept: exp . $end
 292     1 exp: exp . OP exp
 293
 294     $end  shift, and go to state 3
 295     OP    shift, and go to state 4
 296
 297
 298 state 3
 299
 300     0 $accept: exp $end .
 301
 302     $default  accept
 303
 304
 305 state 4
 306
 307     1 exp: . exp OP exp
 308     1    | exp OP . exp
 309     2    | . NUM
 310
 311     NUM  shift, and go to state 1
 312
 313     exp  go to state 5
 314
 315
 316 state 5
 317
 318     1 exp: exp . OP exp
 319     1    | exp OP exp .  [$end, OP]
 320
 321     $default  reduce using rule 1 (exp)
 322
 323     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 324 ]])
 325
 326 AT_CLEANUP
 327
 328
 329 ## ---------------------- ##
 330 ## %precedence suffices.  ##
 331 ## ---------------------- ##
 332
 333 AT_SETUP([%precedence suffices])
 334
 335 AT_DATA([input.y],
 336 [[%precedence "then"
 337 %precedence "else"
 338 %%
 339 stmt:
 340   "if" cond "then" stmt
 341 | "if" cond "then" stmt "else" stmt
 342 | "stmt"
 343 ;
 344
 345 cond:
 346   "exp"
 347 ;
 348 ]])
 349
 350 AT_BISON_CHECK([-o input.c input.y])
 351
 352 AT_CLEANUP
 353
 354
 355 ## ------------------------------ ##
 356 ## %precedence does not suffice.  ##
 357 ## ------------------------------ ##
 358
 359 AT_SETUP([%precedence does not suffice])
 360
 361 AT_DATA([input.y],
 362 [[%precedence "then"
 363 %precedence "else"
 364 %%
 365 stmt:
 366   "if" cond "then" stmt
 367 | "if" cond "then" stmt "else" stmt
 368 | "stmt"
 369 ;
 370
 371 cond:
 372   "exp"
 373 | cond "then" cond
 374 ;
 375 ]])
 376
 377 AT_BISON_CHECK([-o input.c input.y], 0, [],
 378 [[input.y: conflicts: 1 shift/reduce
 379 input.y:12.3-18: warning: rule useless in parser due to conflicts: cond: cond "then" cond
 380 ]])
 381
 382 AT_CLEANUP
 383
 384
 385 ## -------------------------------- ##
 386 ## Defaulted Conflicted Reduction.  ##
 387 ## -------------------------------- ##
 388
 389 # When there are RR conflicts, some rules are disabled.  Usually it is
 390 # simply displayed as:
 391 #
 392 #    $end           reduce using rule 3 (num)
 393 #    $end           [reduce using rule 4 (id)]
 394 #
 395 # But when `reduce 3' is the default action, we'd produce:
 396 #
 397 #    $end           [reduce using rule 4 (id)]
 398 #    $default    reduce using rule 3 (num)
 399 #
 400 # In this precise case (a reduction is masked by the default
 401 # reduction), we make the `reduce 3' explicit:
 402 #
 403 #    $end           reduce using rule 3 (num)
 404 #    $end           [reduce using rule 4 (id)]
 405 #    $default    reduce using rule 3 (num)
 406 #
 407 # Maybe that's not the best display, but then, please propose something
 408 # else.
 409
 410 AT_SETUP([Defaulted Conflicted Reduction])
 411 AT_KEYWORDS([report])
 412
 413 AT_DATA([input.y],
 414 [[%%
 415 exp: num | id;
 416 num: '0';
 417 id : '0';
 418 %%
 419 ]])
 420
 421 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 422 [[input.y: conflicts: 1 reduce/reduce
 423 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
 424 ]])
 425
 426 # Check the contents of the report.
 427 AT_CHECK([cat input.output], [],
 428 [[Rules useless in parser due to conflicts
 429
 430     4 id: '0'
 431
 432
 433 State 1 conflicts: 1 reduce/reduce
 434
 435
 436 Grammar
 437
 438     0 $accept: exp $end
 439
 440     1 exp: num
 441     2    | id
 442
 443     3 num: '0'
 444
 445     4 id: '0'
 446
 447
 448 Terminals, with rules where they appear
 449
 450 $end (0) 0
 451 '0' (48) 3 4
 452 error (256)
 453
 454
 455 Nonterminals, with rules where they appear
 456
 457 $accept (4)
 458     on left: 0
 459 exp (5)
 460     on left: 1 2, on right: 0
 461 num (6)
 462     on left: 3, on right: 1
 463 id (7)
 464     on left: 4, on right: 2
 465
 466
 467 state 0
 468
 469     0 $accept: . exp $end
 470     1 exp: . num
 471     2    | . id
 472     3 num: . '0'
 473     4 id: . '0'
 474
 475     '0'  shift, and go to state 1
 476
 477     exp  go to state 2
 478     num  go to state 3
 479     id   go to state 4
 480
 481
 482 state 1
 483
 484     3 num: '0' .  [$end]
 485     4 id: '0' .  [$end]
 486
 487     $end      reduce using rule 3 (num)
 488     $end      [reduce using rule 4 (id)]
 489     $default  reduce using rule 3 (num)
 490
 491
 492 state 2
 493
 494     0 $accept: exp . $end
 495
 496     $end  shift, and go to state 5
 497
 498
 499 state 3
 500
 501     1 exp: num .
 502
 503     $default  reduce using rule 1 (exp)
 504
 505
 506 state 4
 507
 508     2 exp: id .
 509
 510     $default  reduce using rule 2 (exp)
 511
 512
 513 state 5
 514
 515     0 $accept: exp $end .
 516
 517     $default  accept
 518 ]])
 519
 520 AT_CLEANUP
 521
 522
 523
 524
 525 ## -------------------- ##
 526 ## %expect not enough.  ##
 527 ## -------------------- ##
 528
 529 AT_SETUP([%expect not enough])
 530
 531 AT_DATA([input.y],
 532 [[%token NUM OP
 533 %expect 0
 534 %%
 535 exp: exp OP exp | NUM;
 536 ]])
 537
 538 AT_BISON_CHECK([-o input.c input.y], 1, [],
 539 [input.y: conflicts: 1 shift/reduce
 540 input.y: expected 0 shift/reduce conflicts
 541 ])
 542 AT_CLEANUP
 543
 544
 545 ## --------------- ##
 546 ## %expect right.  ##
 547 ## --------------- ##
 548
 549 AT_SETUP([%expect right])
 550
 551 AT_DATA([input.y],
 552 [[%token NUM OP
 553 %expect 1
 554 %%
 555 exp: exp OP exp | NUM;
 556 ]])
 557
 558 AT_BISON_CHECK([-o input.c input.y])
 559 AT_CLEANUP
 560
 561
 562 ## ------------------ ##
 563 ## %expect too much.  ##
 564 ## ------------------ ##
 565
 566 AT_SETUP([%expect too much])
 567
 568 AT_DATA([input.y],
 569 [[%token NUM OP
 570 %expect 2
 571 %%
 572 exp: exp OP exp | NUM;
 573 ]])
 574
 575 AT_BISON_CHECK([-o input.c input.y], 1, [],
 576 [input.y: conflicts: 1 shift/reduce
 577 input.y: expected 2 shift/reduce conflicts
 578 ])
 579 AT_CLEANUP
 580
 581
 582 ## ------------------------------ ##
 583 ## %expect with reduce conflicts  ##
 584 ## ------------------------------ ##
 585
 586 AT_SETUP([%expect with reduce conflicts])
 587
 588 AT_DATA([input.y],
 589 [[%expect 0
 590 %%
 591 program: a 'a' | a a;
 592 a: 'a';
 593 ]])
 594
 595 AT_BISON_CHECK([-o input.c input.y], 1, [],
 596 [input.y: conflicts: 1 reduce/reduce
 597 input.y: expected 0 reduce/reduce conflicts
 598 ])
 599 AT_CLEANUP
 600
 601
 602 ## ------------------------------- ##
 603 ## %no-default-prec without %prec  ##
 604 ## ------------------------------- ##
 605
 606 AT_SETUP([%no-default-prec without %prec])
 607
 608 AT_DATA([[input.y]],
 609 [[%left '+'
 610 %left '*'
 611
 612 %%
 613
 614 %no-default-prec;
 615
 616 e:   e '+' e
 617    | e '*' e
 618    | '0'
 619    ;
 620 ]])
 621
 622 AT_BISON_CHECK([-o input.c input.y], 0, [],
 623 [[input.y: conflicts: 4 shift/reduce
 624 ]])
 625 AT_CLEANUP
 626
 627
 628 ## ---------------------------- ##
 629 ## %no-default-prec with %prec  ##
 630 ## ---------------------------- ##
 631
 632 AT_SETUP([%no-default-prec with %prec])
 633
 634 AT_DATA([[input.y]],
 635 [[%left '+'
 636 %left '*'
 637
 638 %%
 639
 640 %no-default-prec;
 641
 642 e:   e '+' e %prec '+'
 643    | e '*' e %prec '*'
 644    | '0'
 645    ;
 646 ]])
 647
 648 AT_BISON_CHECK([-o input.c input.y])
 649 AT_CLEANUP
 650
 651
 652 ## ---------------- ##
 653 ## %default-prec    ##
 654 ## ---------------- ##
 655
 656 AT_SETUP([%default-prec])
 657
 658 AT_DATA([[input.y]],
 659 [[%left '+'
 660 %left '*'
 661
 662 %%
 663
 664 %default-prec;
 665
 666 e:   e '+' e
 667    | e '*' e
 668    | '0'
 669    ;
 670 ]])
 671
 672 AT_BISON_CHECK([-o input.c input.y])
 673 AT_CLEANUP
 674
 675
 676 ## ---------------------------------------------- ##
 677 ## Unreachable States After Conflict Resolution.  ##
 678 ## ---------------------------------------------- ##
 679
 680 AT_SETUP([[Unreachable States After Conflict Resolution]])
 681
 682 # If conflict resolution makes states unreachable, remove those states, report
 683 # rules that are then unused, and don't report conflicts in those states.  Test
 684 # what happens when a nonterminal becomes useless as a result of state removal
 685 # since that causes lalr.o's goto map to be rewritten.
 686
 687 AT_DATA([[input.y]],
 688 [[%output "input.c"
 689 %left 'a'
 690
 691 %%
 692
 693 start: resolved_conflict 'a' reported_conflicts 'a' ;
 694
 695 /* S/R conflict resolved as reduce, so the state with item
 696  * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
 697  * unreachable, and the associated production is useless.  */
 698 resolved_conflict:
 699     'a' unreachable1
 700   | %prec 'a'
 701   ;
 702
 703 /* S/R conflict that need not be reported since it is unreachable because of
 704  * the previous conflict resolution.  Nonterminal unreachable1 and all its
 705  * productions are useless.  */
 706 unreachable1:
 707     'a' unreachable2
 708   |
 709   ;
 710
 711 /* Likewise for a R/R conflict and nonterminal unreachable2.  */
 712 unreachable2: | ;
 713
 714 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
 715  * when their states are renumbered due to state removal.  */
 716 reported_conflicts:
 717     'a'
 718   | 'a'
 719   |
 720   ;
 721
 722 ]])
 723
 724 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 725 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
 726 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
 727 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
 728 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 729 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 730 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 731 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 732 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 733 ]])
 734
 735 AT_CHECK([[cat input.output]], 0,
 736 [[Rules useless in parser due to conflicts
 737
 738     2 resolved_conflict: 'a' unreachable1
 739
 740     4 unreachable1: 'a' unreachable2
 741     5             | /* empty */
 742
 743     6 unreachable2: /* empty */
 744     7             | /* empty */
 745
 746     9 reported_conflicts: 'a'
 747    10                   | /* empty */
 748
 749
 750 State 4 conflicts: 1 shift/reduce
 751 State 5 conflicts: 1 reduce/reduce
 752
 753
 754 Grammar
 755
 756     0 $accept: start $end
 757
 758     1 start: resolved_conflict 'a' reported_conflicts 'a'
 759
 760     2 resolved_conflict: 'a' unreachable1
 761     3                  | /* empty */
 762
 763     4 unreachable1: 'a' unreachable2
 764     5             | /* empty */
 765
 766     6 unreachable2: /* empty */
 767     7             | /* empty */
 768
 769     8 reported_conflicts: 'a'
 770     9                   | 'a'
 771    10                   | /* empty */
 772
 773
 774 Terminals, with rules where they appear
 775
 776 $end (0) 0
 777 'a' (97) 1 2 4 8 9
 778 error (256)
 779
 780
 781 Nonterminals, with rules where they appear
 782
 783 $accept (4)
 784     on left: 0
 785 start (5)
 786     on left: 1, on right: 0
 787 resolved_conflict (6)
 788     on left: 2 3, on right: 1
 789 unreachable1 (7)
 790     on left: 4 5, on right: 2
 791 unreachable2 (8)
 792     on left: 6 7, on right: 4
 793 reported_conflicts (9)
 794     on left: 8 9 10, on right: 1
 795
 796
 797 state 0
 798
 799     0 $accept: . start $end
 800     1 start: . resolved_conflict 'a' reported_conflicts 'a'
 801     2 resolved_conflict: . 'a' unreachable1
 802     3                  | .  ['a']
 803
 804     $default  reduce using rule 3 (resolved_conflict)
 805
 806     start              go to state 1
 807     resolved_conflict  go to state 2
 808
 809     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 810
 811
 812 state 1
 813
 814     0 $accept: start . $end
 815
 816     $end  shift, and go to state 3
 817
 818
 819 state 2
 820
 821     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 822
 823     'a'  shift, and go to state 4
 824
 825
 826 state 3
 827
 828     0 $accept: start $end .
 829
 830     $default  accept
 831
 832
 833 state 4
 834
 835     1 start: resolved_conflict 'a' . reported_conflicts 'a'
 836     8 reported_conflicts: . 'a'
 837     9                   | . 'a'
 838    10                   | .  ['a']
 839
 840     'a'  shift, and go to state 5
 841
 842     'a'  [reduce using rule 10 (reported_conflicts)]
 843
 844     reported_conflicts  go to state 6
 845
 846
 847 state 5
 848
 849     8 reported_conflicts: 'a' .  ['a']
 850     9                   | 'a' .  ['a']
 851
 852     'a'       reduce using rule 8 (reported_conflicts)
 853     'a'       [reduce using rule 9 (reported_conflicts)]
 854     $default  reduce using rule 8 (reported_conflicts)
 855
 856
 857 state 6
 858
 859     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 860
 861     'a'  shift, and go to state 7
 862
 863
 864 state 7
 865
 866     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 867
 868     $default  reduce using rule 1 (start)
 869 ]])
 870
 871 AT_DATA([[input-keep.y]],
 872 [[%define lr.keep_unreachable_states
 873 ]])
 874 AT_CHECK([[cat input.y >> input-keep.y]])
 875
 876 AT_BISON_CHECK([[input-keep.y]], 0, [],
 877 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
 878 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 879 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 880 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 881 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 882 ]])
 883
 884 AT_CLEANUP
 885
 886
 887 ## ------------------------------------------------------------ ##
 888 ## Solved conflicts report for multiple reductions in a state.  ##
 889 ## ------------------------------------------------------------ ##
 890
 891 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
 892
 893 # Used to lose earlier solved conflict messages even within a single S/R/R.
 894
 895 AT_DATA([[input.y]],
 896 [[%left 'a'
 897 %right 'b'
 898 %right 'c'
 899 %right 'd'
 900 %%
 901 start:
 902     'a'
 903   | empty_a 'a'
 904   | 'b'
 905   | empty_b 'b'
 906   | 'c'
 907   | empty_c1 'c'
 908   | empty_c2 'c'
 909   | empty_c3 'c'
 910   ;
 911 empty_a: %prec 'a' ;
 912 empty_b: %prec 'b' ;
 913 empty_c1: %prec 'c' ;
 914 empty_c2: %prec 'c' ;
 915 empty_c3: %prec 'd' ;
 916 ]])
 917 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 918 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
 919 [[state 0
 920
 921     0 $accept: . start $end
 922     1 start: . 'a'
 923     2      | . empty_a 'a'
 924     3      | . 'b'
 925     4      | . empty_b 'b'
 926     5      | . 'c'
 927     6      | . empty_c1 'c'
 928     7      | . empty_c2 'c'
 929     8      | . empty_c3 'c'
 930     9 empty_a: .  ['a']
 931    10 empty_b: .  []
 932    11 empty_c1: .  []
 933    12 empty_c2: .  []
 934    13 empty_c3: .  ['c']
 935
 936     'b'  shift, and go to state 1
 937
 938     'c'       reduce using rule 13 (empty_c3)
 939     $default  reduce using rule 9 (empty_a)
 940
 941     start     go to state 2
 942     empty_a   go to state 3
 943     empty_b   go to state 4
 944     empty_c1  go to state 5
 945     empty_c2  go to state 6
 946     empty_c3  go to state 7
 947
 948     Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
 949     Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
 950     Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
 951     Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
 952     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
 953
 954
 955 state 1
 956 ]])
 957
 958 AT_CLEANUP
 959
 960
 961 ## ------------------------------------------------------------ ##
 962 ## %nonassoc error actions for multiple reductions in a state.  ##
 963 ## ------------------------------------------------------------ ##
 964
 965 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
 966 # multiple reductions in a state.
 967
 968 # For a %nonassoc error action token, used to print the first remaining
 969 # reduction on that token without brackets.
 970
 971 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
 972
 973 AT_DATA([[input.y]],
 974 [[%nonassoc 'a' 'b' 'c'
 975 %%
 976 start:
 977     'a'
 978   | empty_a 'a'
 979   | 'b'
 980   | empty_b 'b'
 981   | 'c'
 982   | empty_c1 'c'
 983   | empty_c2 'c'
 984   | empty_c3 'c'
 985   ;
 986 empty_a: %prec 'a' ;
 987 empty_b: %prec 'b' ;
 988 empty_c1: %prec 'c' ;
 989 empty_c2: %prec 'c' ;
 990 empty_c3: %prec 'c' ;
 991 ]])
 992
 993 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 994 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
 995 [[state 0
 996
 997     0 $accept: . start $end
 998     1 start: . 'a'
 999     2      | . empty_a 'a'
1000     3      | . 'b'
1001     4      | . empty_b 'b'
1002     5      | . 'c'
1003     6      | . empty_c1 'c'
1004     7      | . empty_c2 'c'
1005     8      | . empty_c3 'c'
1006     9 empty_a: .  []
1007    10 empty_b: .  []
1008    11 empty_c1: .  []
1009    12 empty_c2: .  ['c']
1010    13 empty_c3: .  ['c']
1011
1012     'a'  error (nonassociative)
1013     'b'  error (nonassociative)
1014     'c'  error (nonassociative)
1015
1016     'c'  [reduce using rule 12 (empty_c2)]
1017     'c'  [reduce using rule 13 (empty_c3)]
1018
1019     start     go to state 1
1020     empty_a   go to state 2
1021     empty_b   go to state 3
1022     empty_c1  go to state 4
1023     empty_c2  go to state 5
1024     empty_c3  go to state 6
1025
1026     Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1027     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1028     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1029
1030
1031 state 1
1032 ]])
1033 AT_CLEANUP