cex: label all the derivations by their initial action

From

    input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
      Example: A b .
      First derivation
        a
        `-> A b .
      Second derivation
        a
        `-> A b
              `-> b .

to

    input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
      Example: A b .
      First reduce derivation
        a
        `-> A b .
      Second reduce derivation
        a
        `-> A b
              `-> b .

* src/counterexample.c (print_counterexample): here.
Compute the width of the labels to properly align the values.
* tests/conflicts.at, tests/counterexample.at, tests/diagnostics.at,
* tests/report.at: Adjust.

src/counterexample.c

@@ -26,6 +26,7 @@
 #include <gl_linked_list.h>
 #include <gl_rbtreehash_list.h>
 #include <hash.h>
+#include <mbswidth.h>
 #include <stdlib.h>
 #include <textstyle.h>
 #include <time.h>
@@ -112,15 +113,37 @@ free_counterexample (counterexample *cex)
   free (cex);
 }
 
+static int max (int a, int b)
+{
+  return a < b ? b : a;
+}
+
 static void
 print_counterexample (const counterexample *cex, FILE *out, const char *prefix)
 {
   const bool flat = getenv ("YYFLAT");
-  fprintf (out, flat ? "  %s%-20s " : "  %s%s: ",
-           prefix, cex->unifying ? _("Example") : _("First example"));
+  const char *example1_label
+    = cex->unifying ? _("Example") : _("First example");
+  const char *example2_label
+    = cex->unifying ? _("Example") : _("Second example");
+  const char *deriv1_label
+    = cex->shift_reduce ? _("Shift derivation") : _("First reduce derivation");
+  const char *deriv2_label
+    = cex->shift_reduce ? _("Reduce derivation") : _("Second reduce derivation");
+  const int width =
+    max (max (mbswidth (example1_label, 0), mbswidth (example2_label, 0)),
+         max (mbswidth (deriv1_label, 0),   mbswidth (deriv2_label, 0)));
+  if (flat)
+    fprintf (out, "  %s%s%*s ", prefix,
+             example1_label, width - mbswidth (example1_label, 0), "");
+  else
+    fprintf (out, "  %s%s: ", prefix, example1_label);
   derivation_print_leaves (cex->d1, out);
-  fprintf (out, flat ? "  %s%-20s " : "  %s%s",
-           prefix, cex->shift_reduce ? _("Shift derivation") : _("First derivation"));
+  if (flat)
+    fprintf (out, "  %s%s%*s ", prefix,
+             deriv1_label, width - mbswidth (deriv1_label, 0), "");
+  else
+    fprintf (out, "  %s%s", prefix, deriv1_label);
   derivation_print (cex->d1, out, prefix);
 
   // If we output to the terminal (via stderr) and we have color
@@ -128,12 +151,18 @@ print_counterexample (const counterexample *cex, FILE *out, const char *prefix)
   // to see the differences.
   if (!cex->unifying || is_styled (stderr))
     {
-      fprintf (out, flat ? "  %s%-20s " : "  %s%s: ",
-               prefix, cex->unifying ? _("Example") : _("Second example"));
+      if (flat)
+        fprintf (out, "  %s%s%*s ", prefix,
+                 example2_label, width - mbswidth (example2_label, 0), "");
+      else
+        fprintf (out, "  %s%s: ", prefix, example2_label);
       derivation_print_leaves (cex->d2, out);
     }
-  fprintf (out, flat ? "  %s%-20s " : "  %s%s",
-           prefix, cex->shift_reduce ? _("Reduce derivation") : _("Second derivation"));
+  if (flat)
+    fprintf (out, "  %s%s%*s ", prefix,
+             deriv2_label, width - mbswidth (deriv2_label, 0), "");
+  else
+    fprintf (out, "  %s%s", prefix, deriv2_label);
   derivation_print (cex->d2, out, prefix);
 
   if (out != stderr)

tests/conflicts.at

@@ -1213,11 +1213,11 @@ State 1
         3 num: '0' .
         4 id: '0' .
       Example: '0' .
-      First derivation
+      First reduce derivation
         exp
         `-> num
             `-> '0' .
-      Second derivation
+      Second reduce derivation
         exp
         `-> id
             `-> '0' .
@@ -1807,10 +1807,10 @@ State 5
         8 reported_conflicts: 'a' .
         9 reported_conflicts: 'a' .
       Example: 'a' .
-      First derivation
+      First reduce derivation
         reported_conflicts
         `-> 'a' .
-      Second derivation
+      Second reduce derivation
         reported_conflicts
         `-> 'a' .
 
@@ -1997,11 +1997,11 @@ AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
        12 empty_c2: . %empty
        13 empty_c3: . %empty
       Example: . 'c'
-      First derivation
+      First reduce derivation
         start
         `-> empty_c2 'c'
             `-> .
-      Second derivation
+      Second reduce derivation
         start
         `-> empty_c3 'c'
             `-> .

tests/counterexample.at

@@ -68,9 +68,9 @@ input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              A . B C
-  Shift derivation     s -> [ y -> [ A . B ] c -> [ C ] ]
-  Reduce derivation    s -> [ a -> [ A . ] x -> [ B C ] ]
+  Example           A . B C
+  Shift derivation  s -> [ y -> [ A . B ] c -> [ C ] ]
+  Reduce derivation s -> [ a -> [ A . ] x -> [ B C ] ]
 input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -125,13 +125,13 @@ input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              A . B C
-  Shift derivation     s -> [ ac -> [ A ac -> [ b -> [ . B ] ] C ] ]
-  Reduce derivation    s -> [ a -> [ A . ] bc -> [ B C ] ]
+  Example           A . B C
+  Shift derivation  s -> [ ac -> [ A ac -> [ b -> [ . B ] ] C ] ]
+  Reduce derivation s -> [ a -> [ A . ] bc -> [ B C ] ]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              A A . B B C C
-  Shift derivation     s -> [ ac -> [ A ac -> [ A ac -> [ b -> [ . b -> [ B B ] ] ] C ] C ] ]
-  Reduce derivation    s -> [ a -> [ A a -> [ A . ] ] bc -> [ B bc -> [ B C ] C ] ]
+  Example           A A . B B C C
+  Shift derivation  s -> [ ac -> [ A ac -> [ A ac -> [ b -> [ . b -> [ B B ] ] ] C ] C ] ]
+  Reduce derivation s -> [ a -> [ A a -> [ A . ] ] bc -> [ B bc -> [ B C ] C ] ]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -187,14 +187,14 @@ input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              A . B
-  Shift derivation     s -> [ A xby -> [ . B ] ]
-  Reduce derivation    s -> [ ax -> [ A x -> [ . ] ] by -> [ B y -> [ ] ] ]
+  Example           A . B
+  Shift derivation  s -> [ A xby -> [ . B ] ]
+  Reduce derivation s -> [ ax -> [ A x -> [ . ] ] by -> [ B y -> [ ] ] ]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  First example        A X . B Y $end
-  Shift derivation     $accept -> [ s -> [ A xby -> [ X xby -> [ . B ] Y ] ] $end ]
-  Second example       A X . B y $end
-  Reduce derivation    $accept -> [ s -> [ ax -> [ A x -> [ X x -> [ . ] ] ] by -> [ B y ] ] $end ]
+  First example     A X . B Y $end
+  Shift derivation  $accept -> [ s -> [ A xby -> [ X xby -> [ . B ] Y ] ] $end ]
+  Second example    A X . B y $end
+  Reduce derivation $accept -> [ s -> [ ax -> [ A x -> [ X x -> [ . ] ] ] by -> [ B y ] ] $end ]
 input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -238,10 +238,10 @@ input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token C [-Wcounterexamples]
-  First example        B . C $end
-  Shift derivation     $accept -> [ g -> [ x -> [ bc -> [ B . C ] ] ] $end ]
-  Second example       B . C D $end
-  Reduce derivation    $accept -> [ g -> [ x -> [ b -> [ B . ] cd -> [ C D ] ] ] $end ]
+  First example     B . C $end
+  Shift derivation  $accept -> [ g -> [ x -> [ bc -> [ B . C ] ] ] $end ]
+  Second example    B . C D $end
+  Reduce derivation $accept -> [ g -> [ x -> [ b -> [ B . ] cd -> [ C D ] ] ] $end ]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -283,10 +283,10 @@ input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
-  First example        A . A B $end
-  Shift derivation     $accept -> [ s -> [ t -> [ y -> [ A . A B ] ] ] $end ]
-  Second example       A . A $end
-  Reduce derivation    $accept -> [ s -> [ s -> [ t -> [ x -> [ A . ] ] ] t -> [ x -> [ A ] ] ] $end ]
+  First example     A . A B $end
+  Shift derivation  $accept -> [ s -> [ t -> [ y -> [ A . A B ] ] ] $end ]
+  Second example    A . A $end
+  Reduce derivation $accept -> [ s -> [ s -> [ t -> [ x -> [ A . ] ] ] t -> [ x -> [ A ] ] ] $end ]
 ]])
 
 AT_CLEANUP
@@ -342,14 +342,14 @@ input.y:8.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
-  Example              b . A X X Y
-  Shift derivation     a -> [ s -> [ b . xx -> [ A X X ] y -> [ Y ] ] ]
-  Reduce derivation    a -> [ r -> [ b . ] t -> [ A x -> [ X ] xy -> [ X Y ] ] ]
+  Example           b . A X X Y
+  Shift derivation  a -> [ s -> [ b . xx -> [ A X X ] y -> [ Y ] ] ]
+  Reduce derivation a -> [ r -> [ b . ] t -> [ A x -> [ X ] xy -> [ X Y ] ] ]
 input.y: warning: shift/reduce conflict on token X [-Wcounterexamples]
-  First example        A X . X
-  Shift derivation     a -> [ t -> [ A xx -> [ X . X ] ] ]
-  Second example       X . X xy
-  Reduce derivation    a -> [ x -> [ X . ] t -> [ X xy ] ]
+  First example     A X . X
+  Shift derivation  a -> [ t -> [ A xx -> [ X . X ] ] ]
+  Second example    X . X xy
+  Reduce derivation a -> [ x -> [ X . ] t -> [ X xy ] ]
 input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 input.y:8.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
@@ -373,10 +373,10 @@ AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
   Example: A b .
-  First derivation
+  First reduce derivation
     a
     `-> A b .
-  Second derivation
+  Second reduce derivation
     a
     `-> A b
           `-> b .
@@ -384,9 +384,9 @@ input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
-  Example              A b .
-  First derivation     a -> [ A b . ]
-  Second derivation    a -> [ A b -> [ b . ] ]
+  Example                  A b .
+  First reduce derivation  a -> [ A b . ]
+  Second reduce derivation a -> [ A b -> [ b . ] ]
 input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -410,13 +410,13 @@ AT_BISON_CHECK_CEX(
 [[input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on tokens A, C [-Wcounterexamples]
   First example: D . A $end
-  First derivation
+  First reduce derivation
     $accept
     `-> s             $end
         `-> a       A
             `-> D .
   Second example: B D . A $end
-  Second derivation
+  Second reduce derivation
     $accept
     `-> s               $end
         `-> B b       A
@@ -425,10 +425,10 @@ input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on tokens A, C [-Wcounterexamples]
-  First example        D . A $end
-  First derivation     $accept -> [ s -> [ a -> [ D . ] A ] $end ]
-  Second example       B D . A $end
-  Second derivation    $accept -> [ s -> [ B b -> [ D . ] A ] $end ]
+  First example            D . A $end
+  First reduce derivation  $accept -> [ s -> [ a -> [ D . ] A ] $end ]
+  Second example           B D . A $end
+  Second reduce derivation $accept -> [ s -> [ B b -> [ D . ] A ] $end ]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -469,10 +469,10 @@ input.y:4.4-6: warning: rule useless in parser due to conflicts [-Wother]
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token J [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        H i . J K $end
-  Shift derivation     $accept -> [ a -> [ H i -> [ i . J K ] ] $end ]
-  Second example       H i . J $end
-  Reduce derivation    $accept -> [ s -> [ a -> [ H i . ] J ] $end ]
+  First example     H i . J K $end
+  Shift derivation  $accept -> [ a -> [ H i -> [ i . J K ] ] $end ]
+  Second example    H i . J $end
+  Reduce derivation $accept -> [ s -> [ a -> [ H i . ] J ] $end ]
 input.y:4.4-6: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -528,13 +528,13 @@ input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              N A . B C
-  Shift derivation     s -> [ n -> [ N b -> [ A . B C ] ] ]
-  Reduce derivation    s -> [ n -> [ N a -> [ A . ] B ] C ]
+  Example           N A . B C
+  Shift derivation  s -> [ n -> [ N b -> [ A . B C ] ] ]
+  Reduce derivation s -> [ n -> [ N a -> [ A . ] B ] C ]
 input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
-  Example              N N A . B D C
-  Shift derivation     s -> [ n -> [ N n -> [ N b -> [ A . B D ] ] C ] ]
-  Reduce derivation    s -> [ n -> [ N n -> [ N a -> [ A . ] B ] D ] C ]
+  Example           N N A . B D C
+  Shift derivation  s -> [ n -> [ N n -> [ N b -> [ A . B D ] ] C ] ]
+  Reduce derivation s -> [ n -> [ N n -> [ N a -> [ A . ] B ] D ] C ]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -563,12 +563,12 @@ AT_BISON_CHECK_CEX(
 [[input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
   Example: B . b c
-  First derivation
+  First reduce derivation
     S
     `-> B                        C
         `-> A       b A          `-> A          c A
             `-> B .   `-> %empty     `-> %empty   `-> %empty
-  Second derivation
+  Second reduce derivation
     S
     `-> B C
           `-> A                          c A
@@ -577,12 +577,12 @@ input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
                       `-> .   `-> %empty
 input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
   Example: C . c b
-  First derivation
+  First reduce derivation
     S
     `-> C                        B
         `-> A       c A          `-> A          b A
             `-> C .   `-> %empty     `-> %empty   `-> %empty
-  Second derivation
+  Second reduce derivation
     S
     `-> C B
           `-> A                          b A
@@ -592,13 +592,13 @@ input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
 ]],
 [[input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
-  Example              B . b c
-  First derivation     S -> [ B -> [ A -> [ B . ] b A -> [ ] ] C -> [ A -> [ ] c A -> [ ] ] ]
-  Second derivation    S -> [ B C -> [ A -> [ B -> [ A -> [ . ] b A -> [ ] ] ] c A -> [ ] ] ]
+  Example                  B . b c
+  First reduce derivation  S -> [ B -> [ A -> [ B . ] b A -> [ ] ] C -> [ A -> [ ] c A -> [ ] ] ]
+  Second reduce derivation S -> [ B C -> [ A -> [ B -> [ A -> [ . ] b A -> [ ] ] ] c A -> [ ] ] ]
 input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
-  Example              C . c b
-  First derivation     S -> [ C -> [ A -> [ C . ] c A -> [ ] ] B -> [ A -> [ ] b A -> [ ] ] ]
-  Second derivation    S -> [ C B -> [ A -> [ C -> [ A -> [ . ] c A -> [ ] ] ] b A -> [ ] ] ]
+  Example                  C . c b
+  First reduce derivation  S -> [ C -> [ A -> [ C . ] c A -> [ ] ] B -> [ A -> [ ] b A -> [ ] ] ]
+  Second reduce derivation S -> [ C B -> [ A -> [ C -> [ A -> [ . ] c A -> [ ] ] ] b A -> [ ] ] ]
 ]])
 
 AT_CLEANUP
@@ -623,13 +623,13 @@ AT_BISON_CHECK_CEX(
 input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
   First example: . c A A $end
-  First derivation
+  First reduce derivation
     $accept
     `-> a                   $end
         `-> b     d
             `-> . `-> c A A
   Second example: . c A A $end
-  Second derivation
+  Second reduce derivation
     $accept
     `-> a                   $end
         `-> c     d
@@ -637,7 +637,7 @@ input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
   First example: b . c A A $end
-  First derivation
+  First reduce derivation
     $accept
     `-> a                             $end
         `-> b d
@@ -645,7 +645,7 @@ time limit exceeded: XXX
                   `-> b     d
                       `-> . `-> c A A
   Second example: b . A $end
-  Second derivation
+  Second reduce derivation
     $accept
     `-> a                 $end
         `-> b d
@@ -654,7 +654,7 @@ time limit exceeded: XXX
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
   First example: c . c A A $end
-  First derivation
+  First reduce derivation
     $accept
     `-> a                             $end
         `-> c d
@@ -662,7 +662,7 @@ time limit exceeded: XXX
                   `-> b     d
                       `-> . `-> c A A
   Second example: c . A $end
-  Second derivation
+  Second reduce derivation
     $accept
     `-> a                 $end
         `-> c d
@@ -687,7 +687,7 @@ time limit exceeded: XXX
                                 `-> . `-> c A A
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
   First example: b c . c A A $end
-  First derivation
+  First reduce derivation
     $accept
     `-> a                                       $end
         `-> b d
@@ -697,7 +697,7 @@ input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
                             `-> b     d
                                 `-> . `-> c A A
   Second example: b c . A $end
-  Second derivation
+  Second reduce derivation
     $accept
     `-> a                           $end
         `-> b d
@@ -722,19 +722,19 @@ input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
                             `-> .
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
   Example: b d .
-  First derivation
+  First reduce derivation
     a
     `-> b d .
-  Second derivation
+  Second reduce derivation
     a
     `-> b d
           `-> d .
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
   Example: c d .
-  First derivation
+  First reduce derivation
     a
     `-> c d .
-  Second derivation
+  Second reduce derivation
     a
     `-> c d
           `-> d .
@@ -744,46 +744,46 @@ input.y:6.15: warning: rule useless in parser due to conflicts [-Wother]
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
-  First example        . c A A $end
-  First derivation     $accept -> [ a -> [ b -> [ . ] d -> [ c A A ] ] $end ]
-  Second example       . c A A $end
-  Second derivation    $accept -> [ a -> [ c -> [ . ] d -> [ c A A ] ] $end ]
+  First example            . c A A $end
+  First reduce derivation  $accept -> [ a -> [ b -> [ . ] d -> [ c A A ] ] $end ]
+  Second example           . c A A $end
+  Second reduce derivation $accept -> [ a -> [ c -> [ . ] d -> [ c A A ] ] $end ]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        b . c A A $end
-  First derivation     $accept -> [ a -> [ b d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] $end ]
-  Second example       b . A $end
-  Second derivation    $accept -> [ a -> [ b d -> [ c -> [ . ] A ] ] $end ]
+  First example            b . c A A $end
+  First reduce derivation  $accept -> [ a -> [ b d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] $end ]
+  Second example           b . A $end
+  Second reduce derivation $accept -> [ a -> [ b d -> [ c -> [ . ] A ] ] $end ]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        c . c A A $end
-  First derivation     $accept -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] $end ]
-  Second example       c . A $end
-  Second derivation    $accept -> [ a -> [ c d -> [ c -> [ . ] A ] ] $end ]
+  First example            c . c A A $end
+  First reduce derivation  $accept -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] $end ]
+  Second example           c . A $end
+  Second reduce derivation $accept -> [ a -> [ c d -> [ c -> [ . ] A ] ] $end ]
 input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        b c . A
-  Shift derivation     a -> [ b d -> [ c . A ] ]
-  Second example       b c . c A A $end
-  Reduce derivation    $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
+  First example     b c . A
+  Shift derivation  a -> [ b d -> [ c . A ] ]
+  Second example    b c . c A A $end
+  Reduce derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
 input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
-  First example        b c . c A A $end
-  First derivation     $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
-  Second example       b c . A $end
-  Second derivation    $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
+  First example            b c . c A A $end
+  First reduce derivation  $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
+  Second example           b c . A $end
+  Second reduce derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
 input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
-  First example        b c . A
-  Shift derivation     a -> [ b d -> [ c . A ] ]
-  Second example       b c . A $end
-  Reduce derivation    $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
+  First example     b c . A
+  Shift derivation  a -> [ b d -> [ c . A ] ]
+  Second example    b c . A $end
+  Reduce derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
-  Example              b d .
-  First derivation     a -> [ b d . ]
-  Second derivation    a -> [ b d -> [ d . ] ]
+  Example                  b d .
+  First reduce derivation  a -> [ b d . ]
+  Second reduce derivation a -> [ b d -> [ d . ] ]
 input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
-  Example              c d .
-  First derivation     a -> [ c d . ]
-  Second derivation    a -> [ c d -> [ d . ] ]
+  Example                  c d .
+  First reduce derivation  a -> [ c d . ]
+  Second reduce derivation a -> [ c d -> [ d . ] ]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 input.y:6.15: warning: rule useless in parser due to conflicts [-Wother]
 ]])
@@ -824,9 +824,9 @@ input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token J [-Wcounterexamples]
-  Example              H i J . J J
-  Shift derivation     s -> [ a -> [ H i J . J ] J ]
-  Reduce derivation    s -> [ a -> [ H i -> [ i J . ] J J ] ]
+  Example           H i J . J J
+  Shift derivation  s -> [ a -> [ H i J . J ] J ]
+  Reduce derivation s -> [ a -> [ H i -> [ i J . ] J J ] ]
 input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -868,9 +868,9 @@ input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
-  Example              A a . D
-  Shift derivation     s -> [ A a d -> [ . D ] ]
-  Reduce derivation    s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] ]
+  Example           A a . D
+  Shift derivation  s -> [ A a d -> [ . D ] ]
+  Reduce derivation s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] ]
 ]])
 
 AT_CLEANUP
@@ -913,10 +913,10 @@ input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
-  First example        A a . D $end
-  Shift derivation     $accept -> [ s -> [ A a d -> [ . D ] ] $end ]
-  Second example       A a . D E $end
-  Reduce derivation    $accept -> [ s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] E ] $end ]
+  First example     A a . D $end
+  Shift derivation  $accept -> [ s -> [ A a d -> [ . D ] ] $end ]
+  Second example    A a . D E $end
+  Reduce derivation $accept -> [ s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] E ] $end ]
 ]])
 
 AT_CLEANUP

tests/diagnostics.at

@@ -619,7 +619,7 @@ input.y:31.4: <warning>warning:</warning> empty rule without %empty [<warning>-W
       |    <warning>^</warning>
       |    <fixit-insert>%empty</fixit-insert>
 input.y: <error>error:</error> reduce/reduce conflicts: 1 found, 0 expected
-input.y: <warning>warning:</warning> reduce/reduce conflict on token "X" [<warning>-Wcounterexamples</warning>]
+input.y: <warning>warning:</warning> reduce/reduce conflict on token "X" [<warning>-Wcounterexamples</warning>]
   Example: <cex-0><cex-1><cex-2><cex-3><cex-leaf>"X"</cex-leaf> <cex-dot>•</cex-dot></cex-3></cex-2></cex-1><cex-4></cex-4><cex-5><cex-6><cex-7><cex-8><cex-9><cex-10> <cex-leaf>"X"</cex-leaf></cex-10></cex-9></cex-8><cex-11> <cex-leaf>"quuux"</cex-leaf></cex-11></cex-7></cex-6></cex-5><cex-12><cex-13><cex-14> <cex-leaf>"X"</cex-leaf></cex-14></cex-13></cex-12></cex-0>
   First reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
@@ -629,7 +629,7 @@ input.y: <warning>warning:</warning> reduce/reduce conflict on token "X" [<warni
     <cex-3><cex-step>      ↳ <cex-leaf>"X"</cex-leaf><cex-dot> •</cex-dot></cex-step></cex-3><cex-7><cex-step>         ↳ <cex-8><cex-step>x1</cex-step></cex-8><cex-11><cex-step>        foo4</cex-step></cex-11></cex-step></cex-7><cex-14><cex-step>          ↳ <cex-leaf>"X"</cex-leaf></cex-step></cex-14>
     <cex-8><cex-step>                        ↳ <cex-9><cex-step>x2</cex-step></cex-9></cex-step></cex-8><cex-11><cex-step>      ↳ <cex-leaf>"quuux"</cex-leaf></cex-step></cex-11>
     <cex-9><cex-step>                          ↳ <cex-10><cex-step>x3</cex-step></cex-10></cex-step></cex-9>
-    <cex-10><cex-step>                            ↳ <cex-leaf>"X"</cex-leaf></cex-step></cex-10>
+    <cex-10><cex-step>                            ↳ <cex-leaf>"X"</cex-leaf></cex-step></cex-10>
   Example: <cex-0><cex-1><cex-2><cex-3><cex-leaf>"X"</cex-leaf> <cex-dot>•</cex-dot></cex-3></cex-2></cex-1><cex-4></cex-4><cex-5><cex-6><cex-7><cex-8><cex-9><cex-10> <cex-leaf>"X"</cex-leaf></cex-10></cex-9></cex-8><cex-11> <cex-leaf>"quuux"</cex-leaf></cex-11></cex-7></cex-6></cex-5><cex-12><cex-13><cex-14> <cex-leaf>"X"</cex-leaf></cex-14></cex-13></cex-12></cex-0>
   Second reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>

tests/report.at

@@ -1549,10 +1549,10 @@ input.y: warning: shift/reduce conflict on token "⊕" [-Wcounterexamples]
       ↳ exp "+" exp •
 input.y: warning: reduce/reduce conflict on tokens $end, "+", "⊕" [-Wcounterexamples]
   Example: exp "+" exp •
-  First derivation
+  First reduce derivation
     exp
     ↳ exp "+" exp •
-  Second derivation
+  Second reduce derivation
     exp
     ↳ exp "+" exp •
 input.y: warning: shift/reduce conflict on token "⊕" [-Wcounterexamples]
@@ -1756,10 +1756,10 @@ State 7
         2 exp: exp "+" exp •
         3 exp: exp "+" exp •
       Example: exp "+" exp •
-      First derivation
+      First reduce derivation
         exp
         ↳ exp "+" exp •
-      Second derivation
+      Second reduce derivation
         exp
         ↳ exp "+" exp •