tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008, 2009 Free Software
   4 # Foundation, 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_DATA_GRAMMAR([input.y],
  54 [[
  55 %{
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59
  60 #define YYERROR_VERBOSE 1
  61 static void
  62 yyerror (const char *msg)
  63 {
  64   fprintf (stderr, "%s\n", msg);
  65 }
  66
  67 /* The current argument. */
  68 static const char *input;
  69
  70 static int
  71 yylex (void)
  72 {
  73   static size_t toknum;
  74   if (! (toknum <= strlen (input)))
  75     abort ();
  76   return input[toknum++];
  77 }
  78
  79 %}
  80
  81 %nonassoc '<' '>'
  82
  83 %%
  84 expr: expr '<' expr
  85     | expr '>' expr
  86     | '0'
  87     ;
  88 %%
  89 int
  90 main (int argc, const char *argv[])
  91 {
  92   input = argc <= 1 ? "" : argv[1];
  93   return yyparse ();
  94 }
  95 ]])
  96
  97 # Specify the output files to avoid problems on different file systems.
  98 AT_BISON_CHECK([-o input.c input.y])
  99 AT_COMPILE([input])
 100
 101 AT_PARSER_CHECK([./input '0<0'])
 102 # FIXME: This is an actual bug, but a new one, in the sense that
 103 # no one has ever spotted it!  The messages are *wrong*: there should
 104 # be nothing there, it should be expected eof.
 105 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 106          [syntax error, unexpected '<', expecting '<' or '>'
 107 ])
 108
 109 AT_PARSER_CHECK([./input '0>0'])
 110 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 111          [syntax error, unexpected '>', expecting '<' or '>'
 112 ])
 113
 114 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 115          [syntax error, unexpected '>', expecting '<' or '>'
 116 ])
 117
 118 AT_CLEANUP
 119
 120
 121
 122 ## ------------------------- ##
 123 ## Unresolved SR Conflicts.  ##
 124 ## ------------------------- ##
 125
 126 AT_SETUP([Unresolved SR Conflicts])
 127
 128 AT_KEYWORDS([report])
 129
 130 AT_DATA([input.y],
 131 [[%token NUM OP
 132 %%
 133 exp: exp OP exp | NUM;
 134 ]])
 135
 136 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 137 [input.y: conflicts: 1 shift/reduce
 138 ])
 139
 140 # Check the contents of the report.
 141 AT_CHECK([cat input.output], [],
 142 [[State 5 conflicts: 1 shift/reduce
 143
 144
 145 Grammar
 146
 147     0 $accept: exp $end
 148
 149     1 exp: exp OP exp
 150     2    | NUM
 151
 152
 153 Terminals, with rules where they appear
 154
 155 $end (0) 0
 156 error (256)
 157 NUM (258) 2
 158 OP (259) 1
 159
 160
 161 Nonterminals, with rules where they appear
 162
 163 $accept (5)
 164     on left: 0
 165 exp (6)
 166     on left: 1 2, on right: 0 1
 167
 168
 169 state 0
 170
 171     0 $accept: . exp $end
 172     1 exp: . exp OP exp
 173     2    | . NUM
 174
 175     NUM  shift, and go to state 1
 176
 177     exp  go to state 2
 178
 179
 180 state 1
 181
 182     2 exp: NUM .
 183
 184     $default  reduce using rule 2 (exp)
 185
 186
 187 state 2
 188
 189     0 $accept: exp . $end
 190     1 exp: exp . OP exp
 191
 192     $end  shift, and go to state 3
 193     OP    shift, and go to state 4
 194
 195
 196 state 3
 197
 198     0 $accept: exp $end .
 199
 200     $default  accept
 201
 202
 203 state 4
 204
 205     1 exp: . exp OP exp
 206     1    | exp OP . exp
 207     2    | . NUM
 208
 209     NUM  shift, and go to state 1
 210
 211     exp  go to state 5
 212
 213
 214 state 5
 215
 216     1 exp: exp . OP exp
 217     1    | exp OP exp .  [$end, OP]
 218
 219     OP  shift, and go to state 4
 220
 221     OP        [reduce using rule 1 (exp)]
 222     $default  reduce using rule 1 (exp)
 223 ]])
 224
 225 AT_CLEANUP
 226
 227
 228
 229 ## ----------------------- ##
 230 ## Resolved SR Conflicts.  ##
 231 ## ----------------------- ##
 232
 233 AT_SETUP([Resolved SR Conflicts])
 234
 235 AT_KEYWORDS([report])
 236
 237 AT_DATA([input.y],
 238 [[%token NUM OP
 239 %left OP
 240 %%
 241 exp: exp OP exp | NUM;
 242 ]])
 243
 244 AT_BISON_CHECK([-o input.c --report=all input.y])
 245
 246 # Check the contents of the report.
 247 AT_CHECK([cat input.output], [],
 248 [[Grammar
 249
 250     0 $accept: exp $end
 251
 252     1 exp: exp OP exp
 253     2    | NUM
 254
 255
 256 Terminals, with rules where they appear
 257
 258 $end (0) 0
 259 error (256)
 260 NUM (258) 2
 261 OP (259) 1
 262
 263
 264 Nonterminals, with rules where they appear
 265
 266 $accept (5)
 267     on left: 0
 268 exp (6)
 269     on left: 1 2, on right: 0 1
 270
 271
 272 state 0
 273
 274     0 $accept: . exp $end
 275     1 exp: . exp OP exp
 276     2    | . NUM
 277
 278     NUM  shift, and go to state 1
 279
 280     exp  go to state 2
 281
 282
 283 state 1
 284
 285     2 exp: NUM .
 286
 287     $default  reduce using rule 2 (exp)
 288
 289
 290 state 2
 291
 292     0 $accept: exp . $end
 293     1 exp: exp . OP exp
 294
 295     $end  shift, and go to state 3
 296     OP    shift, and go to state 4
 297
 298
 299 state 3
 300
 301     0 $accept: exp $end .
 302
 303     $default  accept
 304
 305
 306 state 4
 307
 308     1 exp: . exp OP exp
 309     1    | exp OP . exp
 310     2    | . NUM
 311
 312     NUM  shift, and go to state 1
 313
 314     exp  go to state 5
 315
 316
 317 state 5
 318
 319     1 exp: exp . OP exp
 320     1    | exp OP exp .  [$end, OP]
 321
 322     $default  reduce using rule 1 (exp)
 323
 324     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 325 ]])
 326
 327 AT_CLEANUP
 328
 329
 330 ## ---------------------- ##
 331 ## %precedence suffices.  ##
 332 ## ---------------------- ##
 333
 334 AT_SETUP([%precedence suffices])
 335
 336 AT_DATA([input.y],
 337 [[%precedence "then"
 338 %precedence "else"
 339 %%
 340 stmt:
 341   "if" cond "then" stmt
 342 | "if" cond "then" stmt "else" stmt
 343 | "stmt"
 344 ;
 345
 346 cond:
 347   "exp"
 348 ;
 349 ]])
 350
 351 AT_BISON_CHECK([-o input.c input.y])
 352
 353 AT_CLEANUP
 354
 355
 356 ## ------------------------------ ##
 357 ## %precedence does not suffice.  ##
 358 ## ------------------------------ ##
 359
 360 AT_SETUP([%precedence does not suffice])
 361
 362 AT_DATA([input.y],
 363 [[%precedence "then"
 364 %precedence "else"
 365 %%
 366 stmt:
 367   "if" cond "then" stmt
 368 | "if" cond "then" stmt "else" stmt
 369 | "stmt"
 370 ;
 371
 372 cond:
 373   "exp"
 374 | cond "then" cond
 375 ;
 376 ]])
 377
 378 AT_BISON_CHECK([-o input.c input.y], 0, [],
 379 [[input.y: conflicts: 1 shift/reduce
 380 input.y:12.3-18: warning: rule useless in parser due to conflicts: cond: cond "then" cond
 381 ]])
 382
 383 AT_CLEANUP
 384
 385
 386 ## -------------------------------- ##
 387 ## Defaulted Conflicted Reduction.  ##
 388 ## -------------------------------- ##
 389
 390 # When there are RR conflicts, some rules are disabled.  Usually it is
 391 # simply displayed as:
 392 #
 393 #    $end           reduce using rule 3 (num)
 394 #    $end           [reduce using rule 4 (id)]
 395 #
 396 # But when `reduce 3' is the default action, we'd produce:
 397 #
 398 #    $end           [reduce using rule 4 (id)]
 399 #    $default    reduce using rule 3 (num)
 400 #
 401 # In this precise case (a reduction is masked by the default
 402 # reduction), we make the `reduce 3' explicit:
 403 #
 404 #    $end           reduce using rule 3 (num)
 405 #    $end           [reduce using rule 4 (id)]
 406 #    $default    reduce using rule 3 (num)
 407 #
 408 # Maybe that's not the best display, but then, please propose something
 409 # else.
 410
 411 AT_SETUP([Defaulted Conflicted Reduction])
 412 AT_KEYWORDS([report])
 413
 414 AT_DATA([input.y],
 415 [[%%
 416 exp: num | id;
 417 num: '0';
 418 id : '0';
 419 %%
 420 ]])
 421
 422 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 423 [[input.y: conflicts: 1 reduce/reduce
 424 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
 425 ]])
 426
 427 # Check the contents of the report.
 428 AT_CHECK([cat input.output], [],
 429 [[Rules useless in parser due to conflicts
 430
 431     4 id: '0'
 432
 433
 434 State 1 conflicts: 1 reduce/reduce
 435
 436
 437 Grammar
 438
 439     0 $accept: exp $end
 440
 441     1 exp: num
 442     2    | id
 443
 444     3 num: '0'
 445
 446     4 id: '0'
 447
 448
 449 Terminals, with rules where they appear
 450
 451 $end (0) 0
 452 '0' (48) 3 4
 453 error (256)
 454
 455
 456 Nonterminals, with rules where they appear
 457
 458 $accept (4)
 459     on left: 0
 460 exp (5)
 461     on left: 1 2, on right: 0
 462 num (6)
 463     on left: 3, on right: 1
 464 id (7)
 465     on left: 4, on right: 2
 466
 467
 468 state 0
 469
 470     0 $accept: . exp $end
 471     1 exp: . num
 472     2    | . id
 473     3 num: . '0'
 474     4 id: . '0'
 475
 476     '0'  shift, and go to state 1
 477
 478     exp  go to state 2
 479     num  go to state 3
 480     id   go to state 4
 481
 482
 483 state 1
 484
 485     3 num: '0' .  [$end]
 486     4 id: '0' .  [$end]
 487
 488     $end      reduce using rule 3 (num)
 489     $end      [reduce using rule 4 (id)]
 490     $default  reduce using rule 3 (num)
 491
 492
 493 state 2
 494
 495     0 $accept: exp . $end
 496
 497     $end  shift, and go to state 5
 498
 499
 500 state 3
 501
 502     1 exp: num .
 503
 504     $default  reduce using rule 1 (exp)
 505
 506
 507 state 4
 508
 509     2 exp: id .
 510
 511     $default  reduce using rule 2 (exp)
 512
 513
 514 state 5
 515
 516     0 $accept: exp $end .
 517
 518     $default  accept
 519 ]])
 520
 521 AT_CLEANUP
 522
 523
 524
 525
 526 ## -------------------- ##
 527 ## %expect not enough.  ##
 528 ## -------------------- ##
 529
 530 AT_SETUP([%expect not enough])
 531
 532 AT_DATA([input.y],
 533 [[%token NUM OP
 534 %expect 0
 535 %%
 536 exp: exp OP exp | NUM;
 537 ]])
 538
 539 AT_BISON_CHECK([-o input.c input.y], 1, [],
 540 [input.y: conflicts: 1 shift/reduce
 541 input.y: expected 0 shift/reduce conflicts
 542 ])
 543 AT_CLEANUP
 544
 545
 546 ## --------------- ##
 547 ## %expect right.  ##
 548 ## --------------- ##
 549
 550 AT_SETUP([%expect right])
 551
 552 AT_DATA([input.y],
 553 [[%token NUM OP
 554 %expect 1
 555 %%
 556 exp: exp OP exp | NUM;
 557 ]])
 558
 559 AT_BISON_CHECK([-o input.c input.y])
 560 AT_CLEANUP
 561
 562
 563 ## ------------------ ##
 564 ## %expect too much.  ##
 565 ## ------------------ ##
 566
 567 AT_SETUP([%expect too much])
 568
 569 AT_DATA([input.y],
 570 [[%token NUM OP
 571 %expect 2
 572 %%
 573 exp: exp OP exp | NUM;
 574 ]])
 575
 576 AT_BISON_CHECK([-o input.c input.y], 1, [],
 577 [input.y: conflicts: 1 shift/reduce
 578 input.y: expected 2 shift/reduce conflicts
 579 ])
 580 AT_CLEANUP
 581
 582
 583 ## ------------------------------- ##
 584 ## %expect with reduce conflicts.  ##
 585 ## ------------------------------- ##
 586
 587 AT_SETUP([%expect with reduce conflicts])
 588
 589 AT_DATA([input.y],
 590 [[%expect 0
 591 %%
 592 program: a 'a' | a a;
 593 a: 'a';
 594 ]])
 595
 596 AT_BISON_CHECK([-o input.c input.y], 1, [],
 597 [input.y: conflicts: 1 reduce/reduce
 598 input.y: expected 0 reduce/reduce conflicts
 599 ])
 600 AT_CLEANUP
 601
 602
 603 ## ------------------------- ##
 604 ## %prec with user strings.  ##
 605 ## ------------------------- ##
 606
 607 AT_SETUP([%prec with user string])
 608
 609 AT_DATA([[input.y]],
 610 [[%%
 611 exp:
 612   "foo" %prec "foo"
 613 ;
 614 ]])
 615
 616 AT_BISON_CHECK([-o input.c input.y])
 617 AT_CLEANUP
 618
 619
 620 ## -------------------------------- ##
 621 ## %no-default-prec without %prec.  ##
 622 ## -------------------------------- ##
 623
 624 AT_SETUP([%no-default-prec without %prec])
 625
 626 AT_DATA([[input.y]],
 627 [[%left '+'
 628 %left '*'
 629
 630 %%
 631
 632 %no-default-prec;
 633
 634 e:   e '+' e
 635    | e '*' e
 636    | '0'
 637    ;
 638 ]])
 639
 640 AT_BISON_CHECK([-o input.c input.y], 0, [],
 641 [[input.y: conflicts: 4 shift/reduce
 642 ]])
 643 AT_CLEANUP
 644
 645
 646 ## ----------------------------- ##
 647 ## %no-default-prec with %prec.  ##
 648 ## ----------------------------- ##
 649
 650 AT_SETUP([%no-default-prec with %prec])
 651
 652 AT_DATA([[input.y]],
 653 [[%left '+'
 654 %left '*'
 655
 656 %%
 657
 658 %no-default-prec;
 659
 660 e:   e '+' e %prec '+'
 661    | e '*' e %prec '*'
 662    | '0'
 663    ;
 664 ]])
 665
 666 AT_BISON_CHECK([-o input.c input.y])
 667 AT_CLEANUP
 668
 669
 670 ## --------------- ##
 671 ## %default-prec.  ##
 672 ## --------------- ##
 673
 674 AT_SETUP([%default-prec])
 675
 676 AT_DATA([[input.y]],
 677 [[%left '+'
 678 %left '*'
 679
 680 %%
 681
 682 %default-prec;
 683
 684 e:   e '+' e
 685    | e '*' e
 686    | '0'
 687    ;
 688 ]])
 689
 690 AT_BISON_CHECK([-o input.c input.y])
 691 AT_CLEANUP
 692
 693
 694 ## ---------------------------------------------- ##
 695 ## Unreachable States After Conflict Resolution.  ##
 696 ## ---------------------------------------------- ##
 697
 698 AT_SETUP([[Unreachable States After Conflict Resolution]])
 699
 700 # If conflict resolution makes states unreachable, remove those states, report
 701 # rules that are then unused, and don't report conflicts in those states.  Test
 702 # what happens when a nonterminal becomes useless as a result of state removal
 703 # since that causes lalr.o's goto map to be rewritten.
 704
 705 AT_DATA([[input.y]],
 706 [[%output "input.c"
 707 %left 'a'
 708
 709 %%
 710
 711 start: resolved_conflict 'a' reported_conflicts 'a' ;
 712
 713 /* S/R conflict resolved as reduce, so the state with item
 714  * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
 715  * unreachable, and the associated production is useless.  */
 716 resolved_conflict:
 717     'a' unreachable1
 718   | %prec 'a'
 719   ;
 720
 721 /* S/R conflict that need not be reported since it is unreachable because of
 722  * the previous conflict resolution.  Nonterminal unreachable1 and all its
 723  * productions are useless.  */
 724 unreachable1:
 725     'a' unreachable2
 726   |
 727   ;
 728
 729 /* Likewise for a R/R conflict and nonterminal unreachable2.  */
 730 unreachable2: | ;
 731
 732 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
 733  * when their states are renumbered due to state removal.  */
 734 reported_conflicts:
 735     'a'
 736   | 'a'
 737   |
 738   ;
 739
 740 ]])
 741
 742 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 743 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
 744 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
 745 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
 746 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 747 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 748 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 749 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 750 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 751 ]])
 752
 753 AT_CHECK([[cat input.output]], 0,
 754 [[Rules useless in parser due to conflicts
 755
 756     2 resolved_conflict: 'a' unreachable1
 757
 758     4 unreachable1: 'a' unreachable2
 759     5             | /* empty */
 760
 761     6 unreachable2: /* empty */
 762     7             | /* empty */
 763
 764     9 reported_conflicts: 'a'
 765    10                   | /* empty */
 766
 767
 768 State 4 conflicts: 1 shift/reduce
 769 State 5 conflicts: 1 reduce/reduce
 770
 771
 772 Grammar
 773
 774     0 $accept: start $end
 775
 776     1 start: resolved_conflict 'a' reported_conflicts 'a'
 777
 778     2 resolved_conflict: 'a' unreachable1
 779     3                  | /* empty */
 780
 781     4 unreachable1: 'a' unreachable2
 782     5             | /* empty */
 783
 784     6 unreachable2: /* empty */
 785     7             | /* empty */
 786
 787     8 reported_conflicts: 'a'
 788     9                   | 'a'
 789    10                   | /* empty */
 790
 791
 792 Terminals, with rules where they appear
 793
 794 $end (0) 0
 795 'a' (97) 1 2 4 8 9
 796 error (256)
 797
 798
 799 Nonterminals, with rules where they appear
 800
 801 $accept (4)
 802     on left: 0
 803 start (5)
 804     on left: 1, on right: 0
 805 resolved_conflict (6)
 806     on left: 2 3, on right: 1
 807 unreachable1 (7)
 808     on left: 4 5, on right: 2
 809 unreachable2 (8)
 810     on left: 6 7, on right: 4
 811 reported_conflicts (9)
 812     on left: 8 9 10, on right: 1
 813
 814
 815 state 0
 816
 817     0 $accept: . start $end
 818     1 start: . resolved_conflict 'a' reported_conflicts 'a'
 819     2 resolved_conflict: . 'a' unreachable1
 820     3                  | .  ['a']
 821
 822     $default  reduce using rule 3 (resolved_conflict)
 823
 824     start              go to state 1
 825     resolved_conflict  go to state 2
 826
 827     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 828
 829
 830 state 1
 831
 832     0 $accept: start . $end
 833
 834     $end  shift, and go to state 3
 835
 836
 837 state 2
 838
 839     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 840
 841     'a'  shift, and go to state 4
 842
 843
 844 state 3
 845
 846     0 $accept: start $end .
 847
 848     $default  accept
 849
 850
 851 state 4
 852
 853     1 start: resolved_conflict 'a' . reported_conflicts 'a'
 854     8 reported_conflicts: . 'a'
 855     9                   | . 'a'
 856    10                   | .  ['a']
 857
 858     'a'  shift, and go to state 5
 859
 860     'a'  [reduce using rule 10 (reported_conflicts)]
 861
 862     reported_conflicts  go to state 6
 863
 864
 865 state 5
 866
 867     8 reported_conflicts: 'a' .  ['a']
 868     9                   | 'a' .  ['a']
 869
 870     'a'       reduce using rule 8 (reported_conflicts)
 871     'a'       [reduce using rule 9 (reported_conflicts)]
 872     $default  reduce using rule 8 (reported_conflicts)
 873
 874
 875 state 6
 876
 877     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 878
 879     'a'  shift, and go to state 7
 880
 881
 882 state 7
 883
 884     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 885
 886     $default  reduce using rule 1 (start)
 887 ]])
 888
 889 AT_DATA([[input-keep.y]],
 890 [[%define lr.keep-unreachable-states
 891 ]])
 892 AT_CHECK([[cat input.y >> input-keep.y]])
 893
 894 AT_BISON_CHECK([[input-keep.y]], 0, [],
 895 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
 896 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 897 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 898 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 899 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 900 ]])
 901
 902 AT_CLEANUP
 903
 904
 905 ## ------------------------------------------------------------ ##
 906 ## Solved conflicts report for multiple reductions in a state.  ##
 907 ## ------------------------------------------------------------ ##
 908
 909 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
 910
 911 # Used to lose earlier solved conflict messages even within a single S/R/R.
 912
 913 AT_DATA([[input.y]],
 914 [[%left 'a'
 915 %right 'b'
 916 %right 'c'
 917 %right 'd'
 918 %%
 919 start:
 920     'a'
 921   | empty_a 'a'
 922   | 'b'
 923   | empty_b 'b'
 924   | 'c'
 925   | empty_c1 'c'
 926   | empty_c2 'c'
 927   | empty_c3 'c'
 928   ;
 929 empty_a: %prec 'a' ;
 930 empty_b: %prec 'b' ;
 931 empty_c1: %prec 'c' ;
 932 empty_c2: %prec 'c' ;
 933 empty_c3: %prec 'd' ;
 934 ]])
 935 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 936 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
 937 [[state 0
 938
 939     0 $accept: . start $end
 940     1 start: . 'a'
 941     2      | . empty_a 'a'
 942     3      | . 'b'
 943     4      | . empty_b 'b'
 944     5      | . 'c'
 945     6      | . empty_c1 'c'
 946     7      | . empty_c2 'c'
 947     8      | . empty_c3 'c'
 948     9 empty_a: .  ['a']
 949    10 empty_b: .  []
 950    11 empty_c1: .  []
 951    12 empty_c2: .  []
 952    13 empty_c3: .  ['c']
 953
 954     'b'  shift, and go to state 1
 955
 956     'c'       reduce using rule 13 (empty_c3)
 957     $default  reduce using rule 9 (empty_a)
 958
 959     start     go to state 2
 960     empty_a   go to state 3
 961     empty_b   go to state 4
 962     empty_c1  go to state 5
 963     empty_c2  go to state 6
 964     empty_c3  go to state 7
 965
 966     Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
 967     Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
 968     Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
 969     Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
 970     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
 971
 972
 973 state 1
 974 ]])
 975
 976 AT_CLEANUP
 977
 978
 979 ## ------------------------------------------------------------ ##
 980 ## %nonassoc error actions for multiple reductions in a state.  ##
 981 ## ------------------------------------------------------------ ##
 982
 983 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
 984 # multiple reductions in a state.
 985
 986 # For a %nonassoc error action token, used to print the first remaining
 987 # reduction on that token without brackets.
 988
 989 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
 990
 991 AT_DATA([[input.y]],
 992 [[%nonassoc 'a' 'b' 'c'
 993 %%
 994 start:
 995     'a'
 996   | empty_a 'a'
 997   | 'b'
 998   | empty_b 'b'
 999   | 'c'
1000   | empty_c1 'c'
1001   | empty_c2 'c'
1002   | empty_c3 'c'
1003   ;
1004 empty_a: %prec 'a' ;
1005 empty_b: %prec 'b' ;
1006 empty_c1: %prec 'c' ;
1007 empty_c2: %prec 'c' ;
1008 empty_c3: %prec 'c' ;
1009 ]])
1010
1011 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1012 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
1013 [[state 0
1014
1015     0 $accept: . start $end
1016     1 start: . 'a'
1017     2      | . empty_a 'a'
1018     3      | . 'b'
1019     4      | . empty_b 'b'
1020     5      | . 'c'
1021     6      | . empty_c1 'c'
1022     7      | . empty_c2 'c'
1023     8      | . empty_c3 'c'
1024     9 empty_a: .  []
1025    10 empty_b: .  []
1026    11 empty_c1: .  []
1027    12 empty_c2: .  ['c']
1028    13 empty_c3: .  ['c']
1029
1030     'a'  error (nonassociative)
1031     'b'  error (nonassociative)
1032     'c'  error (nonassociative)
1033
1034     'c'  [reduce using rule 12 (empty_c2)]
1035     'c'  [reduce using rule 13 (empty_c3)]
1036
1037     start     go to state 1
1038     empty_a   go to state 2
1039     empty_b   go to state 3
1040     empty_c1  go to state 4
1041     empty_c2  go to state 5
1042     empty_c3  go to state 6
1043
1044     Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1045     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1046     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1047
1048
1049 state 1
1050 ]])
1051 AT_CLEANUP