cex: suggest -Wcounterexamples when there are unexpected conflicts

Suggesting -Wcounterexamples when there are conflicts is probably not
what the user wants.  If she knows her conflicts and has set
%expect/%expect-rr appropriately, we shouldn't warn.

The commit also swaps the counterexamples and the report of conflicts,
into, IMHO, a more natural order: from

    Shift/reduce conflict on token B:
    1:    3 a: A .
    1:    8 y: A . B
    Example              A • B C
    First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
    Example              A • B C
    Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]

    input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
    input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]

to

    input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
    Shift/reduce conflict on token B:
    1:    3 a: A .
    1:    8 y: A . B
    Example              A • B C
    First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
    Example              A • B C
    Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]

    input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]

* src/conflicts.c (rule_conflicts_print): Rename as...
(report_rule_expectation_mismatches): this.
Move the handling of report_counterexamples to...
(conflicts_print): Here.
Display this warning when applicable.

8 files changed, 112 insertions, 56 deletions

diff --git a/src/conflicts.c b/src/conflicts.c
index 7becadb2..87811f1f 100644
--- a/src/conflicts.c
+++ b/src/conflicts.c
@@ -694,12 +694,12 @@ report_counterexamples (void)
       report_state_counterexamples (states[sn]);
 }
 
-/*------------------------------.
-| Reporting per-rule conflicts. |
-`------------------------------*/
+/*------------------------------------------------.
+| Report per-rule %expect/%expect-rr mismatches.  |
+`------------------------------------------------*/
 
 static void
-rule_conflicts_print (void)
+report_rule_expectation_mismatches (void)
 {
   for (rule_number i = 0; i < nrules; i += 1)
     {
@@ -723,8 +723,6 @@ rule_conflicts_print (void)
                       r->code, rr, expected_rr);
         }
     }
-  if (warning_is_enabled (Wcounterexamples))
-    report_counterexamples ();
 }
 
 /*---------------------------------.
@@ -734,7 +732,7 @@ rule_conflicts_print (void)
 void
 conflicts_print (void)
 {
-  rule_conflicts_print ();
+  report_rule_expectation_mismatches ();
 
   if (! glr_parser && expected_rr_conflicts != -1)
     {
@@ -742,8 +740,9 @@ conflicts_print (void)
       expected_rr_conflicts = -1;
     }
 
-  /* Screams for factoring, but almost useless because of the
-     different strings to translate.  */
+  bool has_unexpected_conflicts = false;
+  /* The following two blocks scream for factoring, but i18n support
+     would make it ugly.  */
   {
     int total = count_sr_conflicts ();
     /* If %expect is not used, but %expect-rr is, then expect 0 sr.  */
@@ -754,16 +753,22 @@ conflicts_print (void)
     if (expected != -1)
       {
         if (expected != total)
-          complain (NULL, complaint,
-                    _("shift/reduce conflicts: %d found, %d expected"),
-                    total, expected);
+          {
+            complain (NULL, complaint,
+                      _("shift/reduce conflicts: %d found, %d expected"),
+                      total, expected);
+            has_unexpected_conflicts = true;
+          }
       }
     else if (total)
-      complain (NULL, Wconflicts_sr,
-                ngettext ("%d shift/reduce conflict",
-                          "%d shift/reduce conflicts",
-                          total),
-                total);
+      {
+        complain (NULL, Wconflicts_sr,
+                  ngettext ("%d shift/reduce conflict",
+                            "%d shift/reduce conflicts",
+                            total),
+                  total);
+        has_unexpected_conflicts = true;
+      }
   }
 
   {
@@ -776,17 +781,29 @@ conflicts_print (void)
     if (expected != -1)
       {
         if (expected != total)
-          complain (NULL, complaint,
-                    _("reduce/reduce conflicts: %d found, %d expected"),
-                    total, expected);
+          {
+            complain (NULL, complaint,
+                      _("reduce/reduce conflicts: %d found, %d expected"),
+                      total, expected);
+            has_unexpected_conflicts = true;
+          }
       }
     else if (total)
-      complain (NULL, Wconflicts_rr,
-                ngettext ("%d reduce/reduce conflict",
-                          "%d reduce/reduce conflicts",
-                          total),
-                total);
+      {
+        complain (NULL, Wconflicts_rr,
+                  ngettext ("%d reduce/reduce conflict",
+                            "%d reduce/reduce conflicts",
+                            total),
+                  total);
+        has_unexpected_conflicts = true;
+      }
   }
+
+  if (warning_is_enabled (Wcounterexamples))
+    report_counterexamples ();
+  else if (has_unexpected_conflicts)
+    complain (NULL, Wother,
+              _("rerun with option '-Wcounterexamples' to generate conflict counterexamples"));
 }
 
 void
diff --git a/tests/conflicts.at b/tests/conflicts.at
index b6d92c5a..807a07c2 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -726,6 +726,7 @@ AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
                [[0]], [[]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -736,6 +737,7 @@ AT_PARSER_CHECK([[input]], [[1]], [[]],
 AT_BISON_CHECK([[-Dlr.type=canonical-lr -Dparse.lac=full \
                  -o input.c input.y]], [[0]], [[]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -746,6 +748,7 @@ AT_PARSER_CHECK([[input]], [[1]], [[]],
 AT_BISON_CHECK([[-Dlr.type=ielr -Dparse.lac=full -o input.c input.y]],
                [[0]], [[]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -770,6 +773,7 @@ exp: exp OP exp | NUM;
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 
 # Check the contents of the report.
@@ -1014,6 +1018,7 @@ cond:
 
 AT_BISON_CHECK([-o input.c input.y], 0, [],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:12.3-18: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1118,6 +1123,7 @@ id : '0';
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:4.6-8: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1238,6 +1244,7 @@ exp: exp OP exp | NUM;
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 [[input.y: error: shift/reduce conflicts: 1 found, 0 expected
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_CLEANUP
 
@@ -1274,6 +1281,7 @@ exp: exp OP exp | NUM;
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 [[input.y: error: shift/reduce conflicts: 1 found, 2 expected
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_CLEANUP
 
@@ -1293,6 +1301,7 @@ a: 'a';
 
 AT_BISON_CHECK([-o input.c input.y], 1, [],
 [[input.y: error: reduce/reduce conflicts: 1 found, 0 expected
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_CLEANUP
 
@@ -1493,6 +1502,7 @@ e:   e '+' e
 
 AT_BISON_CHECK([-Wall -o input.c input.y], 0, [],
 [[input.y: warning: 4 shift/reduce conflicts [-Wconflicts-sr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:1.1-5: warning: useless precedence and associativity for '+' [-Wprecedence]
 input.y:2.1-5: warning: useless precedence and associativity for '*' [-Wprecedence]
 ]])
@@ -1598,6 +1608,7 @@ reported_conflicts:
 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:12.5-20: warning: rule useless in parser due to conflicts [-Wother]
 input.y:20.5-20: warning: rule useless in parser due to conflicts [-Wother]
 input.y:21.4: warning: rule useless in parser due to conflicts [-Wother]
@@ -1756,6 +1767,7 @@ AT_CHECK([[cat input.y >> input-keep.y]])
 AT_BISON_CHECK([[input-keep.y]], 0, [],
 [[input-keep.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
 input-keep.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+input-keep.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input-keep.y:22.4: warning: rule useless in parser due to conflicts [-Wother]
 input-keep.y:26.16: warning: rule useless in parser due to conflicts [-Wother]
 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts [-Wother]
@@ -1939,6 +1951,7 @@ exp: 'a' | 'a';
 AT_BISON_CHECK([[2.y]], [[0]], [],
 [[2.y: warning: %expect-rr applies only to GLR parsers [-Wother]
 2.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+2.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 2.y:3.12-14: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1975,12 +1988,15 @@ B: ;
 AT_BISON_CHECK([[sr-rr.y]], [[0]], [[]],
 [[sr-rr.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 sr-rr.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+sr-rr.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]],
 [[sr-rr.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+sr-rr.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]],
 [[sr-rr.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+sr-rr.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 
 [
@@ -2049,6 +2065,7 @@ for gram in sr-rr sr rr; do
           fi
         } | sed -e "s/^/$file: /" > experr
         ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[
+        echo "$file: error: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Werror=other]" >> experr
         ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[
       fi
     done
diff --git a/tests/counterexample.at b/tests/counterexample.at
index 8647e464..7d677cb8 100644
--- a/tests/counterexample.at
+++ b/tests/counterexample.at
@@ -44,7 +44,8 @@ y: A | A B;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token B:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token B:
 1:    3 a: A .
 1:    8 y: A . B
 Example              A • B C
@@ -52,7 +53,6 @@ First derivation     s ::=[ a ::=[ A • ] x ::=[ B C ] ]
 Example              A • B C
 Second derivation    s ::=[ y ::=[ A • B ] c ::=[ C ] ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -76,7 +76,8 @@ bc: B bc C | B C;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token B:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token B:
 1:    7 a: A .
 1:    5 b: . B
 Example              A • B C
@@ -84,7 +85,6 @@ First derivation     s ::=[ a ::=[ A • ] bc ::=[ B C ] ]
 Example              A • B C
 Second derivation    s ::=[ ac ::=[ A ac ::=[ b ::=[ • B ] ] C ] ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -109,7 +109,8 @@ xby: B | X xby Y;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token B:
+[[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+Shift/reduce conflict on token B:
 1:    4 x: . %empty
 1:    9 xby: . B
 Example              A • B y
@@ -125,7 +126,6 @@ First derivation     $accept ::=[ s ::=[ ax ::=[ A x ::=[ X x ::=[ • ] ] ] by
 Second example       A X • B Y $end
 Second derivation    $accept ::=[ s ::=[ A xby ::=[ X xby ::=[ • B ] Y ] ] $end ]
 
-input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
 input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -150,7 +150,8 @@ bc: B C;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token C:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token C:
 2:    7 b: B .
 2:    9 bc: B . C
 First example        B • C D $end
@@ -158,7 +159,6 @@ First derivation     $accept ::=[ g ::=[ x ::=[ b ::=[ B • ] cd ::=[ C D ] ] ]
 Second example       B • C $end
 Second derivation    $accept ::=[ g ::=[ x ::=[ bc ::=[ B • C ] ] ] $end ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -181,7 +181,8 @@ y: A A B;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token A:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token A:
 1:    5 x: A .
 1:    6 y: A . A B
 First example        A • A $end
@@ -189,7 +190,6 @@ First derivation     $accept ::=[ s ::=[ s ::=[ t ::=[ x ::=[ A • ] ] ] t ::=[
 Second example       A • A B $end
 Second derivation    $accept ::=[ s ::=[ t ::=[ y ::=[ A • A B ] ] ] $end ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 ]])
 
 AT_CLEANUP
@@ -216,7 +216,8 @@ y: Y;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token A:
+[[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+Shift/reduce conflict on token A:
 4:    3 r: b .
 4:    7 s: b . A xx y
 Example              b • A X X Y
@@ -232,7 +233,6 @@ First derivation     a ::=[ x ::=[ X • ] t ::=[ X xy ] ]
 Second example       A X • X
 Second derivation    a ::=[ t ::=[ A xx ::=[ X • X ] ] ]
 
-input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
 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]
 ]])
@@ -254,7 +254,8 @@ b : A | b;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Reduce/reduce conflict on token $end:
+[[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+Reduce/reduce conflict on token $end:
 4:    1 a: A b .
 4:    3 b: b .
 Example              A b •
@@ -262,7 +263,6 @@ First derivation     a ::=[ A b • ]
 Example              A b •
 Second derivation    a ::=[ A b ::=[ b • ] ]
 
-input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
 input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -284,7 +284,8 @@ b: D;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Reduce/reduce conflict on tokens A, C:
+[[input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+Reduce/reduce conflict on tokens A, C:
 2:    5 a: D .
 2:    6 b: D .
 First example        D • A $end
@@ -292,7 +293,6 @@ First derivation     $accept ::=[ s ::=[ a ::=[ D • ] A ] $end ]
 Second example       B D • A $end
 Second derivation    $accept ::=[ s ::=[ B b ::=[ D • ] A ] $end ]
 
-input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -314,7 +314,8 @@ i: X | i J K;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token J:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token J:
 5:    2 a: H i .
 5:    4 i: i . J K
 time limit exceeded: XXX
@@ -323,7 +324,6 @@ First derivation     $accept ::=[ s ::=[ a ::=[ H i • ] J ] $end ]
 Second example       H i • J K $end
 Second derivation    $accept ::=[ a ::=[ H i ::=[ i • J K ] ] $end ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:4.4-6: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -349,7 +349,8 @@ b: A B C | A B D;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token B:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token B:
 4:    7 a: A .
 4:    8 b: A . B C
 Example              N A • B C
@@ -357,7 +358,6 @@ First derivation     s ::=[ n ::=[ N a ::=[ A • ] B ] C ]
 Example              N A • B C
 Second derivation    s ::=[ n ::=[ N b ::=[ A • B C ] ] ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -384,7 +384,8 @@ C : A c A;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Reduce/reduce conflict on tokens b, c:
+[[input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
+Reduce/reduce conflict on tokens b, c:
 3:    3 A: B .
 3:    5 A: . %empty
 Example              B • b A A c A
@@ -400,7 +401,6 @@ First derivation     S ::=[ C ::=[ A ::=[ C • ] c A ] B ::=[ A b A ] ]
 Example              C • c A b A
 Second derivation    S ::=[ C B ::=[ A ::=[ C ::=[ A ::=[ • ] c A ] ] b A ] ]
 
-input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
 ]])
 
 AT_CLEANUP
@@ -422,7 +422,9 @@ d : a | c A | d;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Reduce/reduce conflict on token A:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
+Reduce/reduce conflict on token A:
 0:    3 b: . %empty
 0:    4 c: . %empty
 First example        • c A A $end
@@ -489,8 +491,6 @@ First derivation     a ::=[ c d • ]
 Example              c d •
 Second derivation    a ::=[ c d ::=[ d • ] ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
 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]
 ]])
@@ -516,7 +516,8 @@ i: %empty | i J;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token J:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token J:
 7:    5 i: i J .
 7:    3 a: H i J . J
 Example              H i J • J J
@@ -524,7 +525,6 @@ First derivation     s ::=[ a ::=[ H i ::=[ i J • ] J J ] ]
 Example              H i J • J J
 Second derivation    s ::=[ a ::=[ H i J • J ] J ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -551,7 +551,8 @@ d: D;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token D:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token D:
 3:    5 c: . %empty
 3:    6 d: . D
 Example              A a • D
@@ -559,7 +560,6 @@ First derivation     s ::=[ A a a ::=[ b ::=[ c ::=[ • ] ] ] d ::=[ D ] ]
 Example              A a • D
 Second derivation    s ::=[ A a d ::=[ • D ] ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 ]])
 
 AT_CLEANUP
@@ -584,7 +584,8 @@ d: D;
 ]])
 
 AT_BISON_CHECK_CEX([input.y], [], [],
-[[Shift/reduce conflict on token D:
+[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+Shift/reduce conflict on token D:
 3:    5 c: . %empty
 3:    6 d: . D
 First example        A a • D E $end
@@ -592,7 +593,6 @@ First derivation     $accept ::=[ s ::=[ A a a ::=[ b ::=[ c ::=[ • ] ] ] d ::
 Second example       A a • D $end
 Second derivation    $accept ::=[ s ::=[ A a d ::=[ • D ] ] $end ]
 
-input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 ]])
 
 AT_CLEANUP
diff --git a/tests/existing.at b/tests/existing.at
index da6287d5..d0f6cb95 100644
--- a/tests/existing.at
+++ b/tests/existing.at
@@ -434,6 +434,7 @@ input.y:323.10: warning: empty rule without %empty [-Wempty-rule]
 ]AT_COND_CASE([[canonical LR]],
 [[input.y: warning: 265 shift/reduce conflicts [-Wconflicts-sr]]],
 [[input.y: warning: 65 shift/reduce conflicts [-Wconflicts-sr]]])[
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:39.1-5: warning: useless associativity for FUNC_CALL, use %precedence [-Wprecedence]
 input.y:44.1-5: warning: useless associativity for YNUMBER, use %precedence [-Wprecedence]
 input.y:44.1-5: warning: useless associativity for YSTRING, use %precedence [-Wprecedence]
@@ -1418,6 +1419,7 @@ input.y:591.18: warning: empty rule without %empty [-Wempty-rule]
 input.y: warning: 144 reduce/reduce conflicts [-Wconflicts-rr]]],
 [[input.y: warning: 78 shift/reduce conflicts [-Wconflicts-sr]
 input.y: warning: 10 reduce/reduce conflicts [-Wconflicts-rr]]])[
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:72.1-5: warning: useless associativity for HQUA, use %precedence [-Wprecedence]
 input.y:53.1-6: warning: useless associativity for HASSIGN, use %precedence [-Wprecedence]
 input.y:54.1-5: warning: useless associativity for HORELSE, use %precedence [-Wprecedence]
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 8257088b..fede248d 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -89,6 +89,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr1.c -rall glr-regr1.y]], 0, [],
 [[glr-regr1.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+glr-regr1.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr1])
 AT_PARSER_CHECK([[glr-regr1 BPBPB]], 0,
@@ -213,6 +214,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr2a.c -rall glr-regr2a.y]], 0, [],
 [[glr-regr2a.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
+glr-regr2a.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr2a])
 
@@ -348,6 +350,7 @@ AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-o glr-regr3.c -rall glr-regr3.y]], 0, [],
 [[glr-regr3.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 glr-regr3.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr3.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr3])
 
@@ -444,6 +447,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr4.c -rall glr-regr4.y]], 0, [],
 [[glr-regr4.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr4.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr4])
 
@@ -501,6 +505,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr5.c -rall glr-regr5.y]], 0, [],
 [[glr-regr5.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr5.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr5])
 
@@ -550,6 +555,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr6.c -rall glr-regr6.y]], 0, [],
 [[glr-regr6.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr6.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr6])
 
@@ -640,6 +646,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr7.c -rall glr-regr7.y]], 0, [],
 [[glr-regr7.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr7.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr7])
 
@@ -730,6 +737,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr8.c -rall glr-regr8.y]], 0, [],
 [[glr-regr8.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr8.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr8])
 
@@ -811,6 +819,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr9.c -rall glr-regr9.y]], 0, [],
 [[glr-regr9.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr9.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr9])
 
@@ -868,6 +877,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr10.c -rall glr-regr10.y]], 0, [],
 [[glr-regr10.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr10.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr10])
 
@@ -927,6 +937,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr11.c -rall glr-regr11.y]], 0, [],
 [[glr-regr11.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr11.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr11])
 
@@ -1049,6 +1060,7 @@ AT_BISON_OPTION_POPDEFS
 AT_BISON_CHECK([[-o glr-regr12.c -rall glr-regr12.y]], 0, [],
 [[glr-regr12.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 glr-regr12.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr12.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr12])
 
@@ -1380,6 +1392,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr14.c -rall glr-regr14.y]], 0, [],
 [[glr-regr14.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr14.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr14])
 
@@ -1474,6 +1487,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr15.c -rall glr-regr15.y]], 0, [],
 [[glr-regr15.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr15.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr15])
 
@@ -1535,6 +1549,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr16.c -rall glr-regr16.y]], 0, [],
 [[glr-regr16.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+glr-regr16.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr16])
 
@@ -1610,6 +1625,7 @@ AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-o glr-regr17.c -rall glr-regr17.y]], 0, [],
 [[glr-regr17.y: warning: 3 reduce/reduce conflicts [-Wconflicts-rr]
+glr-regr17.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([glr-regr17])
 
@@ -1703,6 +1719,7 @@ d: /* nada.  */;
 
 AT_BISON_CHECK([[-o input.c input.y]], 0, [],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]])
 AT_COMPILE([input])
 
diff --git a/tests/input.at b/tests/input.at
index db6ff688..1dda9841 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -2882,6 +2882,7 @@ input.y:13.1-14: note: previous definition
 input.y:14.16-29: warning: %define variable 'parse.error' redefined [-Wother]
 input.y:13.16-29: note: previous definition
 input.y: error: reduce/reduce conflicts: 0 found, 42 expected
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y: warning: fix-its can be applied.  Rerun with option '--update'. [-Wother]
 ]])
 
diff --git a/tests/reduce.at b/tests/reduce.at
index 90dad835..e064cebc 100644
--- a/tests/reduce.at
+++ b/tests/reduce.at
@@ -1300,6 +1300,7 @@ dnl INPUT
 dnl BISON-STDERR
 [AT_COND_CASE([[LALR]],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 ]], [])],
 
 dnl TABLES
diff --git a/tests/sets.at b/tests/sets.at
index 76680f78..c8820d30 100644
--- a/tests/sets.at
+++ b/tests/sets.at
@@ -285,6 +285,7 @@ term: 'n'
 
 AT_BISON_CHECK([[-fcaret input.y]], [], [],
 [[input.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]
+input.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
 input.y:2.14-17: warning: rule useless in parser due to conflicts [-Wother]
     2 | expr: term | term | term | term | term | term
       |              ^~~~