version 3.7

* NEWS: Record release date.

.prev-version

@@ -1 +1 @@
-3.6.91
+3.6.93

NEWS

@@ -1,29 +1,6 @@
 GNU Bison NEWS
 
-* Noteworthy changes in release 3.6.92 (2020-07-19) [beta]
-
-Changes in the display of counterexamples.
-
-** Documentation
-
-*** Examples
-
-  The bistromathic demonstrates %param and how to quote sources in the error
-  messages:
-
-    > 123 456
-    1.5-7: syntax error: expected end of file or + or - or * or / or ^ before number
-        1 | 123 456
-          |     ^~~
-
-* Noteworthy changes in release 3.6.91 (2020-07-09) [beta]
-
-** Bug fixes
-
-  Portability issues.
-
-
-* Noteworthy changes in release 3.6.90 (2020-07-04) [beta]
+* Noteworthy changes in release 3.7 (2020-07-23) [stable]
 
 ** Deprecated features
 
@@ -41,52 +18,114 @@ Changes in the display of counterexamples.
 
   Contributed by Vincent Imbimbo.
 
-  When given `--report=counterexamples` or `-Wcounterexamples`, bison will
-  now output counterexamples for conflicts in the grammar.  These are
-  strings in the grammar which can be parsed in two ways due to the
-  conflict.  For example:
+  When given `-Wcounterexamples`/`-Wcex`, bison will now output
+  counterexamples for conflicts.
 
-    Shift/reduce conflict on token "/":
-      Example              exp "+" exp • "/" exp
+**** Unifying Counterexamples
+
+  Unifying counterexamples are strings which can be parsed in two ways due
+  to the conflict.  For example on a grammar that contains the usual
+  "dangling else" ambiguity:
+
+    $ bison else.y
+    else.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+    else.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
+
+    $ bison else.y -Wcex
+    else.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+    else.y: warning: shift/reduce conflict on token "else" [-Wcounterexamples]
+      Example: "if" exp "then" "if" exp "then" exp • "else" exp
       Shift derivation
         exp
-        ↳ exp "+" exp
-                  ↳ exp • "/" exp
-      Example              exp "+" exp • "/" exp
+        ↳ "if" exp "then" exp
+                          ↳ "if" exp "then" exp • "else" exp
+      Example: "if" exp "then" "if" exp "then" exp • "else" exp
       Reduce derivation
         exp
-        ↳ exp             "/" exp
-          ↳ exp "+" exp •
+        ↳ "if" exp "then" exp                     "else" exp
+                          ↳ "if" exp "then" exp •
 
-  When Bison is installed with text styling enabled, the example is actually
-  shown twice, with colors highlighting the ambiguity.
+  When text styling is enabled, colors are used in the examples and the
+  derivations to highlight the structure of both analyses.  In this case,
 
-  This is a shift/reduce conflict caused by none of the operators having
-  precedence, so the example can be parsed in the two ways shown.  When
-  bison cannot find an example that can be derived in two ways, it instead
-  generates two examples that are the same up until the dot:
+    "if" exp "then" [ "if" exp "then" exp • ] "else" exp
 
-    First example        expr • ID ',' ID $end
-    Shift derivation
-      $accept
-      ↳ s                      $end
-        ↳ a                 ID
-          ↳ expr
-            ↳ expr • ID ','
-    Second example       expr • ID $end
-    Reduce derivation
-      $accept
-      ↳ s             $end
-        ↳ a        ID
-          ↳ expr •
+  vs.
+
+    "if" exp "then" [ "if" exp "then" exp • "else" exp ]
+
+
+  The counterexamples are "focused", in two different ways.  First, they do
+  not clutter the output with all the derivations from the start symbol,
+  rather they start on the "conflicted nonterminal". They go straight to the
+  point.  Second, they don't "expand" nonterminal symbols uselessly.
+
+**** Nonunifying Counterexamples
+
+  In the case of the dangling else, Bison found an example that can be
+  parsed in two ways (therefore proving that the grammar is ambiguous).
+  When it cannot find such an example, it instead generates two examples
+  that are the same up until the dot:
+
+    $ bison foo.y
+    foo.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+    foo.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
+    foo.y:4.4-7: warning: rule useless in parser due to conflicts [-Wother]
+        4 | a: expr
+          |    ^~~~
+
+    $ bison -Wcex foo.y
+    foo.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+    foo.y: warning: shift/reduce conflict on token ID [-Wcounterexamples]
+      First example: expr • ID ',' ID $end
+      Shift derivation
+        $accept
+        ↳ s                      $end
+          ↳ a                 ID
+            ↳ expr
+              ↳ expr • ID ','
+      Second example: expr • ID $end
+      Reduce derivation
+        $accept
+        ↳ s             $end
+          ↳ a        ID
+            ↳ expr •
+    foo.y:4.4-7: warning: rule useless in parser due to conflicts [-Wother]
+        4 | a: expr
+          |    ^~~~
 
   In these cases, the parser usually doesn't have enough lookahead to
   differentiate the two given examples.
 
-  The counterexamples are "focused" in two different ways.  First, they do
-  not clutter the output with all the derivations from the start symbol,
-  rather they start on the "conflicted nonterminal". They go straight to the
-  point.  Second, they don't "expand" nonterminal symbols uselessly.
+**** Reports
+
+  Counterexamples are also included in the report when given
+  `--report=counterexamples`/`-rcex` (or `--report=all`), with more
+  technical details:
+
+    State 7
+
+      1 exp: "if" exp "then" exp •  [$end, "then", "else"]
+      2    | "if" exp "then" exp • "else" exp
+
+      "else"  shift, and go to state 8
+
+      "else"    [reduce using rule 1 (exp)]
+      $default  reduce using rule 1 (exp)
+
+      shift/reduce conflict on token "else":
+          1 exp: "if" exp "then" exp •
+          2 exp: "if" exp "then" exp • "else" exp
+        Example: "if" exp "then" "if" exp "then" exp • "else" exp
+        Shift derivation
+          exp
+          ↳ "if" exp "then" exp
+                            ↳ "if" exp "then" exp • "else" exp
+        Example: "if" exp "then" "if" exp "then" exp • "else" exp
+        Reduce derivation
+          exp
+          ↳ "if" exp "then" exp                     "else" exp
+                            ↳ "if" exp "then" exp •
 
 *** File prefix mapping
 
@@ -100,6 +139,11 @@ Changes in the display of counterexamples.
 
 ** Changes
 
+*** Diagnostics
+
+  When text styling is enabled and the terminal supports it, the warnings
+  now include hyperlinks to the documentation.
+
 *** Relocatable installation
 
   When installed to be relocatable (via `configure --enable-relocatable`),
@@ -140,6 +184,18 @@ Changes in the display of counterexamples.
   Now the parser state can be examined when parsing is finished.  The parser
   state is reset when starting a new parse.
 
+** Documentation
+
+*** Examples
+
+  The bistromathic demonstrates %param and how to quote sources in the error
+  messages:
+
+    > 123 456
+    1.5-7: syntax error: expected end of file or + or - or * or / or ^ before number
+        1 | 123 456
+          |     ^~~
+
 ** Bug fixes
 
 *** Include the generated header (yacc.c)
@@ -4405,7 +4461,7 @@ LocalWords:  yysymbol yytnamerr yyreport ctx ARGMAX yysyntax stderr LPAREN
 LocalWords:  symrec yypcontext TOKENMAX yyexpected YYEMPTY yypstate YYEOF
 LocalWords:  autocompletion bistromathic submessages Cayuela lexcalc hoc
 LocalWords:  yytoken YYUNDEF YYerror basename Automake's UTF ifdef ffile
-LocalWords:  gotos readline Imbimbo Wcounterexamples
+LocalWords:  gotos readline Imbimbo Wcounterexamples Wcex Nonunifying rcex
 
 Local Variables:
 ispell-dictionary: "american"

bootstrap.conf

@@ -44,7 +44,7 @@ gnulib_modules='
   realloc-posix
   relocatable-prog relocatable-script
   rename
-  spawn-pipe stdbool stpcpy strdup-posix strerror strverscmp
+  spawn-pipe stdbool stpcpy stpncpy strdup-posix strerror strverscmp
   timevar
   unicodeio unistd unistd-safer unlink unlocked-io
   update-copyright unsetenv verify

doc/bison.texi

@@ -9889,10 +9889,11 @@ initially developed by Chinawat Isradisaikul and Andrew Myers
 As a first example, see the example grammar of @ref{Shift/Reduce}, which
 features on shift/reduce conflict:
 
+@c see doc/if-then-else.y
 @example
 $ @kbd{bison if-then-else.y}
-if-then-else.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-if-then-else.y: warning: rerun with option '-Wcounterexamples' to generate conflict counterexamples [-Wother]
+if-then-else.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+if-then-else.y: @dnotice{note}: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 @end example
 
 @noindent
@@ -9900,32 +9901,46 @@ Let's rerun @command{bison} with the option
 @option{-Wcex}/@option{-Wcounterexamples}@inlinefmt{info, (the following
 output is actually in color)}:
 
-@ifhtml
+@ifnottex
 @example
-Shift/reduce conflict on token "else":
+if-then-else.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+if-then-else.y: @dwarning{warning}: shift/reduce conflict on token "else" [@dwarning{-Wcounterexamples}]
 @group
-  Example            @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @blue{"else" stmt}
-  Shift derivation   @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{"else" stmt ]} @green{]} @yellow{]}
-  Example            @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
-  Reduce derivation  @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
+  Example: @yellow{"if" expr "then"} "if" expr "then" stmt • "else" stmt
+  Shift derivation
+    @yellow{if_stmt}
+    @yellow{↳ "if" expr "then"} @green{stmt}
+                       @green{↳} @blue{if_stmt}
+                         @blue{↳ "if" expr "then" stmt} @red{•} @blue{"else" stmt}
+  Example: @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
+  Reduce derivation
+    @yellow{if_stmt}
+    @yellow{↳ "if" expr "then"} @green{stmt}                        @yellow{"else" stmt}
+                       @green{↳} @blue{if_stmt}
+                         @blue{↳ "if" expr "then" stmt} @red{•}
 @end group
 @end example
-@end ifhtml
-@ifnothtml
-@smallexample
-Shift/reduce conflict on token "else":
+@end ifnottex
+@iftex
+@example
+if-then-else.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+if-then-else.y: @dwarning{warning}: shift/reduce conflict on token "else" [@dwarning{-Wcounterexamples}]
 @group
-  Example
-    @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @blue{"else" stmt}
+  Example: @yellow{"if" expr "then"} "if" expr "then" stmt • "else" stmt
   Shift derivation
-    @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{"else" stmt ]} @green{]} @yellow{]}
-  Example
-    @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
+    @yellow{if_stmt}
+    @yellow{@arrow{} "if" expr "then"} @green{stmt}
+                        @green{@arrow{}} @blue{if_stmt}
+                          @blue{@arrow{} "if" expr "then" stmt} @red{•} @blue{"else" stmt}
+  Example: @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
   Reduce derivation
-    @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
+    @yellow{if_stmt}
+    @yellow{@arrow{} "if" expr "then"} @green{stmt}                        @yellow{"else" stmt}
+                        @green{@arrow{}} @blue{if_stmt}
+                           @blue{@arrow{} "if" expr "then" stmt} @red{•}
 @end group
-@end smallexample
-@end ifnothtml
+@end example
+@end iftex
 
 This shows two different derivations for one single expression.  That
 demonstrates that the grammar is ambiguous.
@@ -9935,6 +9950,7 @@ demonstrates that the grammar is ambiguous.
 As a more delicate example, consider the example grammar of
 @ref{Reduce/Reduce}, which features a reduce/reduce conflict:
 
+@c doc/sequence.y
 @example
 %%
 sequence:
@@ -9950,32 +9966,112 @@ maybeword:
 
 Bison generates the following counterexamples:
 
+@ifnottex
 @example
+@group
 $ @kbd{bison -Wcex sequence.y}
 sequence.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
 sequence.y: @dwarning{warning}: 2 reduce/reduce conflicts [@dwarning{-Wconflicts-rr}]
-Shift/reduce conflict on token "word":
-  Example              @red{•} @green{"word"}
-  Shift derivation     @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
-  Example              @red{•} @yellow{"word"}
-  Reduce derivation    @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @red{•} @green{]} @yellow{"word" ]}
-
-Reduce/reduce conflict on tokens $end, "word":
-  Example              @red{•}
-  First derivation     @yellow{sequence @arrow{} [} @red{•} @yellow{]}
-  Example              @red{•}
-  Second derivation    @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{]} @yellow{]}
-
-Shift/reduce conflict on token "word":
-  Example              @red{•} @green{"word"}
-  Shift derivation     @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
-  Example              @red{•} @yellow{"word"}
-  Reduce derivation    @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @blue{maybeword @arrow{} [} @red{•} @blue{]} @green{]} @yellow{"word" ]}
-
+@end group
+@group
+sequence.y: @dwarning{warning}: shift/reduce conflict on token "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•} @green{"word"}
+  Shift derivation
+    @yellow{sequence}
+    @yellow{↳} @green{maybeword}
+      @green{↳} @red{•} @green{"word"}
+  Example: @red{•} @yellow{"word"}
+  Reduce derivation
+    @yellow{sequence}
+    @yellow{↳} @green{sequence} @yellow{"word"}
+      @green{↳} @red{•}
+@end group
+@group
+sequence.y: @dwarning{warning}: reduce/reduce conflict on tokens $end, "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•}
+  First reduce derivation
+    @yellow{sequence}
+    @yellow{↳} @red{•}
+  Example: @red{•}
+  Second reduce derivation
+    @yellow{sequence}
+    @yellow{↳} @green{maybeword}
+      @green{↳} @red{•}
+@end group
+@group
+sequence.y: @dwarning{warning}: shift/reduce conflict on token "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•} @green{"word"}
+  Shift derivation
+    @yellow{sequence}
+    @yellow{↳} @green{maybeword}
+      @green{↳} @red{•} @green{"word"}
+  Example: @red{•} @yellow{"word"}
+  Reduce derivation
+    @yellow{sequence}
+    @yellow{↳} @green{sequence}    @yellow{"word"}
+      @green{↳} @blue{maybeword}
+        @blue{↳} @red{•}
+@end group
+@group
 sequence.y:8.3-45: @dwarning{warning}: rule useless in parser due to conflicts [@dwarning{-Wother}]
     8 |   @dwarning{%empty    @{ printf ("empty maybeword\n"); @}}
       |   @dwarning{^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~}
+@end group
 @end example
+@end ifnottex
+@iftex
+@example
+@group
+$ @kbd{bison -Wcex sequence.y}
+sequence.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+sequence.y: @dwarning{warning}: 2 reduce/reduce conflicts [@dwarning{-Wconflicts-rr}]
+@end group
+@group
+sequence.y: @dwarning{warning}: shift/reduce conflict on token "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•} @green{"word"}
+  Shift derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @green{maybeword}
+       @green{@arrow{}} @red{•} @green{"word"}
+  Example: @red{•} @yellow{"word"}
+  Reduce derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @green{sequence} @yellow{"word"}
+       @green{@arrow{}} @red{•}
+@end group
+@group
+sequence.y: @dwarning{warning}: reduce/reduce conflict on tokens $end, "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•}
+  First reduce derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @red{•}
+  Example: @red{•}
+  Second reduce derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @green{maybeword}
+       @green{@arrow{}} @red{•}
+@end group
+@group
+sequence.y: @dwarning{warning}: shift/reduce conflict on token "word" [@dwarning{-Wcounterexamples}]
+  Example: @red{•} @green{"word"}
+  Shift derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @green{maybeword}
+       @green{@arrow{}} @red{•} @green{"word"}
+  Example: @red{•} @yellow{"word"}
+  Reduce derivation
+    @yellow{sequence}
+    @yellow{@arrow{}} @green{sequence}    @yellow{"word"}
+      @green{@arrow{}} @blue{maybeword}
+         @blue{@arrow{}} @red{•}
+@end group
+@group
+sequence.y:8.3-45: @dwarning{warning}: rule useless in parser due to conflicts [@dwarning{-Wother}]
+    8 |   @dwarning{%empty    @{ printf ("empty maybeword\n"); @}}
+      |   @dwarning{^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~}
+@end group
+@end example
+@end iftex
 
 Each of these three conflicts, again, prove that the grammar is ambiguous.
 For instance, the second conflict (the reduce/reduce one) shows that the
@@ -9989,6 +10085,7 @@ that are the same up until the dot.  Most notably, this will happen when
 your grammar requires a stronger parser (more lookahead, LR instead of
 LALR).  The following example isn't LR(1):
 
+@c doc/ids.y
 @example
 %token ID
 %%
@@ -9999,13 +10096,58 @@ expr: %empty | expr ID ','
 
 @command{bison} reports:
 
-@smallexample
-Shift/reduce conflict on token ID:
-  First example        @purple{expr} @red{•} @purple{ID ','} @green{ID} @yellow{$end}
-  Shift derivation     @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [} @purple{expr @arrow{} [ expr} @red{•} @purple{ID ',' ]} @blue{]} @green{ID ]} @yellow{$end ]}
-  Second example       @blue{expr} @red{•} @green{ID} @yellow{$end}
-  Reduce derivation    @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [ expr} @red{•} @blue{]} @green{ID ]} @yellow{$end ]}
-@end smallexample
+@ifnottex
+@example
+ids.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+ids.y: @dwarning{warning}: shift/reduce conflict on token ID [@dwarning{-Wcounterexamples}]
+@group
+  First example: @purple{expr} @red{•} @purple{ID ','} @green{ID} @yellow{$end}
+  Shift derivation
+    @yellow{$accept}
+    @yellow{↳} @green{s}                      @yellow{$end}
+      @green{↳} @blue{a}                 @green{ID}
+        @blue{↳} @purple{expr}
+          @purple{↳ expr} @red{•} @purple{ID ','}
+  Second example: @blue{expr} @red{•} @green{ID} @yellow{$end}
+  Reduce derivation
+    @yellow{$accept}
+    @yellow{↳} @green{s}             @yellow{$end}
+      @green{↳} @blue{a}        @green{ID}
+        @blue{↳ expr} @red{•}
+@end group
+@group
+ids.y:4.4-7: @dwarning{warning}: rule useless in parser due to conflicts [@dwarning{-Wother}]
+    4 | a: expr
+      |    ^~~~
+@end group
+@end example
+@end ifnottex
+@iftex
+@example
+ids.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
+ids.y: @dwarning{warning}: shift/reduce conflict on token ID [@dwarning{-Wcounterexamples}]
+@group
+  First example: @purple{expr} @red{•} @purple{ID ','} @green{ID} @yellow{$end}
+  Shift derivation
+    @yellow{$accept}
+    @yellow{@arrow{}} @green{s}                      @yellow{$end}
+       @green{@arrow{}} @blue{a}                 @green{ID}
+          @blue{@arrow{}} @purple{expr}
+             @purple{@arrow{} expr} @red{•} @purple{ID ','}
+  Second example: @blue{expr} @red{•} @green{ID} @yellow{$end}
+  Reduce derivation
+    @yellow{$accept}
+    @yellow{@arrow{}} @green{s}             @yellow{$end}
+       @green{@arrow{}} @blue{a}        @green{ID}
+          @blue{@arrow{} expr} @red{•}
+@end group
+@group
+ids.y:4.4-7: @dwarning{warning}: rule useless in parser due to conflicts [@dwarning{-Wother}]
+    4 | a: expr
+      |    ^~~~
+@end group
+@end example
+@end iftex
 
 This conflict is caused by the parser not having enough information to know
 the difference between these two examples.  The parser would need an
@@ -10041,6 +10183,7 @@ by default.  As a consequence, the verbose output file is called
 
 The following grammar file, @file{calc.y}, will be used in the sequel:
 
+@c doc/calc.y
 @example
 @group
 %union
@@ -10084,7 +10227,7 @@ calc.y:19.1-7: @dwarning{warning}: nonterminal useless in grammar: useless [@dwa
    19 | @dwarning{useless: STR;}
       | @dwarning{^~~~~~~}
 calc.y: @dwarning{warning}: 7 shift/reduce conflicts [@dwarning{-Wconflicts-sr}]
-calc.y: @dwarning{warning}: rerun with option '-Wcounterexamples' to generate conflict counterexamples [@dwarning{-Wother}]
+calc.y: @dnotice{note}: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 @end smallexample
 
 Going back to the calc example, when given @option{--report=state},
@@ -10396,15 +10539,44 @@ When given @option{--report=counterexamples}, @command{bison} will generate
 counterexamples within the report, augmented with the corresponding items
 (@pxref{Counterexamples}).
 
+@ifnottex
 @example
-Shift/reduce conflict on token '/':
+shift/reduce conflict on token '/':
     1 exp: exp '+' exp •
     4 exp: exp • '/' exp
-  Example              @yellow{exp '+'} @green{exp} @red{•} @green{'/' exp}
-  Shift derivation     @yellow{exp @arrow{} [ exp '+'} @green{exp @arrow{} [ exp} @red{•} @green{'/' exp ]} @yellow{]}
-  Example              @green{exp '+' exp} @red{•} @yellow{'/' exp}
-  Reduce derivation    @yellow{exp @arrow{} [} @green{exp @arrow{} [ exp '+' exp} @red{•} @green{]} @yellow{'/' exp ]}
+@group
+  Example: exp '+' exp • '/' exp
+  Shift derivation
+    exp
+    ↳ exp '+' exp
+              ↳ exp • '/' exp
+  Example: exp '+' exp • '/' exp
+  Reduce derivation
+    exp
+    ↳ exp             '/' exp
+      ↳ exp '+' exp •
+@end group
 @end example
+@end ifnottex
+@iftex
+@example
+shift/reduce conflict on token '/':
+    1 exp: exp '+' exp •
+    4 exp: exp • '/' exp
+@group
+  Example: exp '+' exp • '/' exp
+  Shift derivation
+    exp
+    @arrow{} exp '+' exp
+               @arrow{} exp • '/' exp
+  Example: exp '+' exp • '/' exp
+  Reduce derivation
+    exp
+    @arrow{} exp             '/' exp
+       @arrow{} exp '+' exp •
+@end group
+@end example
+@end iftex
 
 This shows two separate derivations in the grammar for the same @code{exp}:
 @samp{e1 + e2 / e3}.  The derivations show how your rules would parse the
@@ -11015,7 +11187,7 @@ The exit status of @command{bison} is:
 @item 0 (success)
 when there were no errors.  Warnings, which are diagnostics about dubious
 constructs, do not change the exit status, unless they are turned into
-errors (@pxref{-Werror,,@option{-Werror}}).
+errors (@pxref{Werror,,@option{-Werror}}).
 
 @item 1 (failure)
 when there were errors.  No file was generated (except the reports generated
@@ -11252,22 +11424,22 @@ Options controlling the diagnostics.
 Output warnings falling in @var{category}.  @var{category} can be one
 of:
 @table @code
-@item conflicts-sr
-@itemx conflicts-rr
+@item @anchor{Wconflicts-sr}conflicts-sr
+@itemx @anchor{Wconflicts-rr}conflicts-rr
 S/R and R/R conflicts.  These warnings are enabled by default.  However, if
 the @code{%expect} or @code{%expect-rr} directive is specified, an
 unexpected number of conflicts is an error, and an expected number of
 conflicts is not reported, so @option{-W} and @option{--warning} then have
 no effect on the conflict report.
 
-@item counterexamples
+@item @anchor{Wcounterexamples}counterexamples
 @itemx cex
 Provide counterexamples for conflicts.  @xref{Counterexamples}.
 Counterexamples take time to compute.  The option @option{-Wcex} should be
 used by the developer when working on the grammar; it hardly makes sense to
 use it in a CI.
 
-@item dangling-alias
+@item @anchor{Wdangling-alias}dangling-alias
 Report string literals that are not bound to a token symbol.
 
 String literals, which allow for better error messages, are (too) liberally
@@ -11313,16 +11485,16 @@ foo: "baz" @{@}
       |      @dwarning{^~~~~}
 @end example
 
-@item deprecated
+@item @anchor{Wdeprecated}deprecated
 Deprecated constructs whose support will be removed in future versions of
 Bison.
 
-@item empty-rule
+@item @anchor{Wempty-rule}empty-rule
 Empty rules without @code{%empty}.  @xref{Empty Rules}.  Disabled by
 default, but enabled by uses of @code{%empty}, unless
 @option{-Wno-empty-rule} was specified.
 
-@item midrule-values
+@item @anchor{Wmidrule-values}midrule-values
 Warn about midrule values that are set but not used within any of the actions
 of the parent rule.
 For example, warn about unused @code{$2} in:
@@ -11342,7 +11514,7 @@ These warnings are not enabled by default since they sometimes prove to
 be false alarms in existing grammars employing the Yacc constructs
 @code{$0} or @code{$-@var{n}} (where @var{n} is some positive integer).
 
-@item precedence
+@item @anchor{Wprecedence}precedence
 Useless precedence and associativity directives.  Disabled by default.
 
 Consider for instance the following grammar:
@@ -11403,20 +11575,21 @@ One would get the exact same parser with the following directives instead:
 @end group
 @end example
 
-@item yacc
+@item @anchor{Wyacc}yacc
 Incompatibilities with POSIX Yacc.
 
-@item other
+@item @anchor{Wother}other
 All warnings not categorized above.  These warnings are enabled by default.
 
 This category is provided merely for the sake of completeness.  Future
 releases of Bison may move warnings from this category to new, more specific
 categories.
 
-@item all
-All the warnings except @code{dangling-alias} and @code{yacc}.
+@item @anchor{Wall}all
+All the warnings except @code{counterexamples}, @code{dangling-alias} and
+@code{yacc}.
 
-@item none
+@item @anchor{Wnone}none
 Turn off all the warnings.
 
 @item error
@@ -11427,8 +11600,7 @@ A category can be turned off by prefixing its name with @samp{no-}.  For
 instance, @option{-Wno-yacc} will hide the warnings about
 POSIX Yacc incompatibilities.
 
-@item -Werror
-@anchor{-Werror}
+@item @anchor{Werror}-Werror
 Turn enabled warnings for every @var{category} into errors, unless they are
 explicitly disabled by @option{-Wno-error=@var{category}}.
 
@@ -15855,7 +16027,7 @@ London, Department of Computer Science, TR-00-12 (December 2000).
 @c LocalWords: TokenKind Automake's rtti Wcounterexamples Chinawat PLDI
 @c LocalWords: Isradisaikul tcite pcite rgbGreen colorGreen rgbYellow Wcex
 @c LocalWords: colorYellow rgbRed colorRed rgbBlue colorBlue rgbPurple
-@c LocalWords: colorPurple ifhtml ifnothtml situ rcex
+@c LocalWords: colorPurple ifhtml ifnothtml situ rcex MERCHANTABILITY Wnone
 
 @c Local Variables:
 @c ispell-dictionary: "american"

doc/calc.y

@@ -0,0 +1,23 @@
+%union
+{
+  int ival;
+  const char *sval;
+}
+
+%token <ival> NUM
+%nterm <ival> exp
+%token <sval> STR
+%nterm <sval> useless
+
+%left '+' '-'
+%left '*'
+
+%%
+exp:
+  exp '+' exp
+| exp '-' exp
+| exp '*' exp
+| exp '/' exp
+| NUM
+;
+useless: STR;

doc/ids.y

@@ -0,0 +1,5 @@
+%token ID
+%%
+s: a ID
+a: expr
+expr: %empty | expr ID ','

doc/if-then-else.y

@@ -0,0 +1,13 @@
+%%
+stmt:
+  expr
+| if_stmt
+;
+
+if_stmt:
+  "if" expr "then" stmt
+| "if" expr "then" stmt "else" stmt
+;
+
+expr:
+  "identifier"

doc/sequence.y

@@ -0,0 +1,10 @@
+%%
+sequence:
+  %empty
+| maybeword
+| sequence "word"
+;
+maybeword:
+  %empty
+| "word"
+;

src/complain.c

@@ -35,6 +35,13 @@
 #include "getargs.h"
 #include "quote.h"
 
+// The URL of the manual page about diagnostics.  Use the per-node
+// manual, to avoid downloading repeatedly the whole manual over the
+// Internet.
+static const char *diagnostics_url
+  = "https://www.gnu.org/software/bison/manual/html_node/Diagnostics.html";
+
+
 err_status complaint_status = status_none;
 
 bool warnings_are_errors = false;
@@ -96,6 +103,20 @@ end_use_class (const char *s, FILE *out)
     }
 }
 
+static void
+begin_hyperlink (FILE *out, const char *ref)
+{
+  if (out == stderr)
+    styled_ostream_set_hyperlink (errstream, ref, NULL);
+}
+
+static void
+end_hyperlink (FILE *out)
+{
+  if (out == stderr)
+    styled_ostream_set_hyperlink (errstream, NULL, NULL);
+}
+
 void
 flush (FILE *out)
 {
@@ -427,9 +448,20 @@ warnings_print_categories (warnings warn_flags, FILE *out)
         const char* style = severity_style (s);
         fputs (" [", out);
         begin_use_class (style, out);
-        fprintf (out, "-W%s%s",
-                 s == severity_error ? "error=" : "",
-                 argmatch_warning_argument (&w));
+        // E.g., "counterexamples".
+        const char *warning = argmatch_warning_argument (&w);
+        char ref[200];
+        snprintf (ref, sizeof ref,
+                  "%s#W%s", diagnostics_url, warning);
+        begin_hyperlink (out, ref);
+        ostream_printf (errstream,
+                        "-W%s%s",
+                        s == severity_error ? "error=" : "",
+                        warning);
+        end_hyperlink (out);
+        // Because we mix stdio with ostream I/O, we need to flush
+        // here for sake of color == debug.
+        flush (out);
         end_use_class (style, out);
         fputc (']', out);
         /* Display only the first match, the second is "-Wall".  */

src/conflicts.c

@@ -686,7 +686,8 @@ conflicts_print (void)
       expected_rr_conflicts = -1;
     }
 
-  bool has_unexpected_conflicts = false;
+  // The warning flags used to emit a diagnostic, if we did.
+  warnings unexpected_conflicts_warning = Wnone;
   /* The following two blocks scream for factoring, but i18n support
      would make it ugly.  */
   {
@@ -703,7 +704,8 @@ conflicts_print (void)
             complain (NULL, complaint,
                       _("shift/reduce conflicts: %d found, %d expected"),
                       total, expected);
-            has_unexpected_conflicts = true;
+            if (total)
+              unexpected_conflicts_warning = complaint;
           }
       }
     else if (total)
@@ -713,7 +715,7 @@ conflicts_print (void)
                             "%d shift/reduce conflicts",
                             total),
                   total);
-        has_unexpected_conflicts = true;
+        unexpected_conflicts_warning = Wconflicts_sr;
       }
   }
 
@@ -731,7 +733,8 @@ conflicts_print (void)
             complain (NULL, complaint,
                       _("reduce/reduce conflicts: %d found, %d expected"),
                       total, expected);
-            has_unexpected_conflicts = true;
+            if (total)
+              unexpected_conflicts_warning = complaint;
           }
       }
     else if (total)
@@ -741,15 +744,16 @@ conflicts_print (void)
                             "%d reduce/reduce conflicts",
                             total),
                   total);
-        has_unexpected_conflicts = true;
+        unexpected_conflicts_warning = Wconflicts_rr;
       }
   }
 
   if (warning_is_enabled (Wcounterexamples))
     report_counterexamples ();
-  else if (has_unexpected_conflicts)
-    complain (NULL, Wother,
-              _("rerun with option '-Wcounterexamples' to generate conflict counterexamples"));
+  else if (unexpected_conflicts_warning != Wnone)
+    subcomplain (NULL, unexpected_conflicts_warning,
+                 _("rerun with option '-Wcounterexamples'"
+                   " to generate conflict counterexamples"));
 }
 
 void

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, "  %s%-20s ",
-           prefix, cex->unifying ? _("Example") : _("First example"));
-  derivation_print_leaves (cex->d1, out, prefix);
-  fprintf (out, flat ? "  %s%-20s " : "  %s%s",
-           prefix, cex->shift_reduce ? _("Shift derivation") : _("First derivation"));
+  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);
+  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
@@ -128,15 +151,22 @@ print_counterexample (const counterexample *cex, FILE *out, const char *prefix)
   // to see the differences.
   if (!cex->unifying || is_styled (stderr))
     {
-      fprintf (out, "  %s%-20s ",
-               prefix, cex->unifying ? _("Example") : _("Second example"));
-      derivation_print_leaves (cex->d2, out, prefix);
+      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);
 
-  fputc ('\n', out);
+  if (out != stderr)
+    putc ('\n', out);
 }
 
 /*
@@ -687,10 +717,10 @@ ssb_equals (const search_state_bundle *s1, const search_state_bundle *s2)
 typedef gl_list_t ssb_list;
 
 static size_t
-visited_hasher (const search_state *ss, size_t max)
+visited_hasher (const search_state *ss, size_t maximum)
 {
-  return (parse_state_hasher (ss->states[0], max)
-          + parse_state_hasher (ss->states[1], max)) % max;
+  return (parse_state_hasher (ss->states[0], maximum)
+          + parse_state_hasher (ss->states[1], maximum)) % maximum;
 }
 
 static bool
@@ -1248,10 +1278,17 @@ counterexample_report_shift_reduce (state_item_number itm1, state_item_number it
                                     symbol_number next_sym,
                                     FILE *out, const char *prefix)
 {
-  fputs (prefix, out);
-  fprintf (out, _("Shift/reduce conflict on token %s:\n"), symbols[next_sym]->tag);
+  if (out == stderr)
+    complain (NULL, Wcounterexamples,
+              _("shift/reduce conflict on token %s"), symbols[next_sym]->tag);
+  else
+    {
+      fputs (prefix, out);
+      fprintf (out, _("shift/reduce conflict on token %s"), symbols[next_sym]->tag);
+      fprintf (out, "%s\n", _(":"));
+    }
   // In the report, print the items.
-  if (*prefix || trace_flag & trace_cex)
+  if (out != stderr || trace_flag & trace_cex)
     {
       print_state_item (&state_items[itm1], out, prefix);
       print_state_item (&state_items[itm2], out, prefix);
@@ -1265,27 +1302,43 @@ counterexample_report_reduce_reduce (state_item_number itm1, state_item_number i
                                      FILE *out, const char *prefix)
 {
   {
-    fputs (prefix, out);
-    fputs (ngettext ("Reduce/reduce conflict on token",
-                     "Reduce/reduce conflict on tokens",
-                     bitset_count (conflict_syms)), out);
+    struct obstack obstack;
+    obstack_init (&obstack);
     bitset_iterator biter;
     state_item_number sym;
-    const char *sep = " ";
+    const char *sep = "";
     BITSET_FOR_EACH (biter, conflict_syms, sym, 0)
       {
-        fprintf (out, "%s%s", sep, symbols[sym]->tag);
+        obstack_printf (&obstack, "%s%s", sep, symbols[sym]->tag);
         sep = ", ";
       }
-    fputs (_(":\n"), out);
+    char *tokens = obstack_finish0 (&obstack);
+    if (out == stderr)
+      complain (NULL, Wcounterexamples,
+                ngettext ("reduce/reduce conflict on token %s",
+                          "reduce/reduce conflict on tokens %s",
+                          bitset_count (conflict_syms)),
+                tokens);
+    else
+      {
+        fputs (prefix, out);
+        fprintf (out,
+                 ngettext ("reduce/reduce conflict on token %s",
+                           "reduce/reduce conflict on tokens %s",
+                           bitset_count (conflict_syms)),
+                 tokens);
+        fprintf (out, "%s\n", _(":"));
+      }
+    obstack_free (&obstack, NULL);
   }
   // In the report, print the items.
-  if (*prefix || trace_flag & trace_cex)
+  if (out != stderr || trace_flag & trace_cex)
     {
       print_state_item (&state_items[itm1], out, prefix);
       print_state_item (&state_items[itm2], out, prefix);
     }
-  counterexample_report (itm1, itm2, bitset_first (conflict_syms), false, out, prefix);
+  counterexample_report (itm1, itm2, bitset_first (conflict_syms),
+                         false, out, prefix);
 }
 
 static state_item_number

src/derivation.c

@@ -193,9 +193,8 @@ all_spaces (const char *s)
 //
 // This function implements this.
 //
-// When COND is true, put S on OUT, preceeded by *PADDING white
-// spaces.  Otherwise add the width to *PADDING.  Return the width of
-// S.
+// When COND is true, put S on OUT, preceded by *PADDING white spaces.
+// Otherwise add the width to *PADDING.  Return the width of S.
 static int
 fputs_if (bool cond, FILE *out, int *padding, const char *s)
 {
@@ -428,10 +427,9 @@ derivation_print_flat (const derivation *deriv, FILE *out, const char *prefix)
 }
 
 void
-derivation_print_leaves (const derivation *deriv, FILE *out, const char *prefix)
+derivation_print_leaves (const derivation *deriv, FILE *out)
 {
   int counter = 0;
-  fputs (prefix, out);
   derivation_print_flat_impl ((derivation *)deriv, out, true, &counter, "");
   fputc ('\n', out);
 }

src/derivation.h

@@ -64,7 +64,7 @@ static inline derivation *derivation_new_leaf (symbol_number sym)
 // Number of symbols.
 size_t derivation_size (const derivation *deriv);
 void derivation_print (const derivation *deriv, FILE *out, const char *prefix);
-void derivation_print_leaves (const derivation *deriv, FILE *out, const char *prefix);
+void derivation_print_leaves (const derivation *deriv, FILE *out);
 void derivation_free (derivation *deriv);
 void derivation_retain (derivation *deriv);
 

src/glyphs.c

@@ -28,24 +28,17 @@
 #include <mbswidth.h>
 #include <unicodeio.h>
 
-// In gnulib/lib/unicodeio.h unicode_to_mb uses a buffer of 25 bytes.
-typedef char glyph_buffer_t[26];
 
-
-static glyph_buffer_t arrow_buf;
-const char *arrow;
+glyph_buffer_t arrow;
 int arrow_width;
 
-static glyph_buffer_t down_arrow_buf;
-const char *down_arrow;
+glyph_buffer_t down_arrow;
 int down_arrow_width;
 
-static glyph_buffer_t dot_buf;
-const char *dot;
+glyph_buffer_t dot;
 int dot_width;
 
-static glyph_buffer_t empty_buf;
-const char *empty;
+glyph_buffer_t empty;
 int empty_width;
 
 const char *derivation_separator = " ";
@@ -53,8 +46,7 @@ int derivation_separator_width = 1;
 
 typedef struct
 {
-  const char **glyph;
-  char *buf;
+  glyph_buffer_t *pbuf;
   const char *fallback;
 } callback_arg_t;
 
@@ -63,8 +55,8 @@ static long
 on_success (const char *buf, size_t buflen, void *callback_arg)
 {
   callback_arg_t *arg = (callback_arg_t *) callback_arg;
-  assert (buflen + 1 < sizeof arg->buf);
-  *stpncpy (arg->buf, buf, buflen) = '\0';
+  assert (buflen + 1 < sizeof *arg->pbuf);
+  *stpncpy (*arg->pbuf, buf, buflen) = '\0';
   return 1;
 }
 
@@ -73,19 +65,17 @@ on_failure (unsigned code MAYBE_UNUSED, const char *msg MAYBE_UNUSED,
             void *callback_arg)
 {
   callback_arg_t *arg = (callback_arg_t *) callback_arg;
-  assert (strlen (arg->fallback) + 1 < sizeof arg->buf);
-  strcpy (arg->buf, arg->fallback);
+  assert (strlen (arg->fallback) + 1 < sizeof *arg->pbuf);
+  strcpy (*arg->pbuf, arg->fallback);
   return 0;
 }
 
 static bool
-glyph_set (const char **glyph,
-           char buf[26], int *width,
+glyph_set (glyph_buffer_t *glyph, int *width,
            unsigned code, const char *fallback)
 {
-  callback_arg_t arg = { glyph, buf, fallback };
+  callback_arg_t arg = { glyph, fallback };
   int res = unicode_to_mb (code, on_success, on_failure, &arg);
-  *glyph = buf;
   *width = mbswidth (*glyph, 0);
   return res;
 }
@@ -93,11 +83,11 @@ glyph_set (const char **glyph,
 void
 glyphs_init (void)
 {
-  glyph_set (&arrow,      arrow_buf,      &arrow_width,      0x2192, "->");
-  glyph_set (&dot,        dot_buf,        &dot_width,        0x2022, ".");
-  glyph_set (&down_arrow, down_arrow_buf, &down_arrow_width, 0x21b3, "`->");
-  glyph_set (&empty,      empty_buf,      &empty_width,      0x03b5, "%empty");
+  glyph_set (&arrow,      &arrow_width,      0x2192, "->");
+  glyph_set (&dot,        &dot_width,        0x2022, ".");
+  glyph_set (&down_arrow, &down_arrow_width, 0x21b3, "`->");
+  glyph_set (&empty,      &empty_width,      0x03b5, "%empty");
 
-  strncat (down_arrow_buf, " ", sizeof down_arrow_buf - strlen (down_arrow_buf) - 1);
+  strncat (down_arrow, " ", sizeof down_arrow - strlen (down_arrow) - 1);
   down_arrow_width += 1;
 }

src/glyphs.h

@@ -23,20 +23,24 @@
 /* Initialize the following variables.  */
 void glyphs_init (void);
 
+/* In gnulib/lib/unicodeio.h unicode_to_mb uses a buffer of 25 bytes.
+   In down_arrow, we append one space.  */
+typedef char glyph_buffer_t[26];
+
 /* "→", separates the lhs of a rule from its rhs.  */
-extern const char *arrow;
+extern glyph_buffer_t arrow;
 extern int arrow_width;
 
 /* "•", a point in an item (aka, a dotted rule).  */
-extern const char *dot;
+extern glyph_buffer_t dot;
 extern int dot_width;
 
 /* "↳ ", below an lhs to announce the rhs.  */
-extern const char *down_arrow;
+extern glyph_buffer_t down_arrow;
 extern int down_arrow_width;
 
 /* "ε", an empty rhs.  */
-extern const char *empty;
+extern glyph_buffer_t empty;
 extern int empty_width;
 
 /* " ", separate symbols in the rhs of a derivation.  */

tests/conflicts.at

@@ -726,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -737,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -748,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([[input]])
 AT_PARSER_CHECK([[input]], [[1]], [[]],
@@ -773,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 
 # Check the contents of the report.
@@ -861,10 +861,10 @@ State 5
     OP        [reduce using rule 1 (exp)]
     $default  reduce using rule 1 (exp)
 
-    Shift/reduce conflict on token OP:
+    shift/reduce conflict on token OP:
         1 exp: exp OP exp .
         1 exp: exp . OP exp
-      Example                  exp OP exp . OP exp
+      Example: exp OP exp . OP exp
       Shift derivation
         exp
         `-> exp OP exp
@@ -1032,7 +1032,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 input.y:12.3-18: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1137,7 +1137,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 input.y:4.6-8: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1209,15 +1209,15 @@ State 1
     $end      [reduce using rule 4 (id)]
     $default  reduce using rule 3 (num)
 
-    Reduce/reduce conflict on token $end:
+    reduce/reduce conflict on token $end:
         3 num: '0' .
         4 id: '0' .
-      Example                  '0' .
-      First derivation
+      Example: '0' .
+      First reduce derivation
         exp
         `-> num
             `-> '0' .
-      Second derivation
+      Second reduce derivation
         exp
         `-> id
             `-> '0' .
@@ -1272,7 +1272,7 @@ 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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_CLEANUP
 
@@ -1309,7 +1309,7 @@ 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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_CLEANUP
 
@@ -1329,7 +1329,7 @@ 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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_CLEANUP
 
@@ -1530,7 +1530,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 input.y:1.1-5: warning: useless precedence and associativity for '+' [-Wprecedence]
 input.y:2.1-5: warning: useless precedence and associativity for '*' [-Wprecedence]
 ]])
@@ -1638,7 +1638,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 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]
@@ -1764,29 +1764,29 @@ State 4
 
     reported_conflicts  go to state 6
 
-    Shift/reduce conflict on token 'a':
+    shift/reduce conflict on token 'a':
        10 reported_conflicts: . %empty
         8 reported_conflicts: . 'a'
-      First example            resolved_conflict . 'a' 'a'
+      First example: resolved_conflict . 'a' 'a'
       Shift derivation
         start
         `-> resolved_conflict reported_conflicts 'a'
                               `-> . 'a'
-      Second example           resolved_conflict . 'a'
+      Second example: resolved_conflict . 'a'
       Reduce derivation
         start
         `-> resolved_conflict reported_conflicts 'a'
                               `-> .
 
-    Shift/reduce conflict on token 'a':
+    shift/reduce conflict on token 'a':
        10 reported_conflicts: . %empty
         9 reported_conflicts: . 'a'
-      First example            resolved_conflict . 'a' 'a'
+      First example: resolved_conflict . 'a' 'a'
       Shift derivation
         start
         `-> resolved_conflict reported_conflicts 'a'
                               `-> . 'a'
-      Second example           resolved_conflict . 'a'
+      Second example: resolved_conflict . 'a'
       Reduce derivation
         start
         `-> resolved_conflict reported_conflicts 'a'
@@ -1803,14 +1803,14 @@ State 5
     'a'       [reduce using rule 9 (reported_conflicts)]
     $default  reduce using rule 8 (reported_conflicts)
 
-    Reduce/reduce conflict on token 'a':
+    reduce/reduce conflict on token 'a':
         8 reported_conflicts: 'a' .
         9 reported_conflicts: 'a' .
-      Example                  'a' .
-      First derivation
+      Example: 'a' .
+      First reduce derivation
         reported_conflicts
         `-> 'a' .
-      Second derivation
+      Second reduce derivation
         reported_conflicts
         `-> 'a' .
 
@@ -1838,7 +1838,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 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]
@@ -1993,15 +1993,15 @@ AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
 
-    Reduce/reduce conflict on token 'c':
+    reduce/reduce conflict on token 'c':
        12 empty_c2: . %empty
        13 empty_c3: . %empty
-      Example                  . 'c'
-      First derivation
+      Example: . 'c'
+      First reduce derivation
         start
         `-> empty_c2 'c'
             `-> .
-      Second derivation
+      Second reduce derivation
         start
         `-> empty_c3 'c'
             `-> .
@@ -2038,7 +2038,7 @@ 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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 2.y:3.12-14: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -2075,15 +2075,14 @@ 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]
+sr-rr.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 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]
+sr-rr.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 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]
 ]])
 
 [
@@ -2140,19 +2139,30 @@ for gram in sr-rr sr rr; do
         ]AT_BISON_CHECK([[-Werror $file]])[
       else
         {
+          issue_note=false
           if test -z "$sr_exp_i" && test "$sr_count" -ne 0; then
             echo "warning: $sr_count shift/reduce conflicts"
+            issue_note=true
           elif test "$sr_exp_i" -ne "$sr_count"; then
             echo "error: shift/reduce conflicts: $sr_count found, $sr_exp_i expected"
+            if test "$sr_count" -ne 0; then
+              issue_note=true
+            fi
           fi
           if test -z "$rr_exp_i" && test "$rr_count" -ne 0; then
             echo "warning: $rr_count reduce/reduce conflicts"
+            issue_note=true
           elif test "$rr_exp_i" -ne "$rr_count"; then
             echo "error: reduce/reduce conflicts: $rr_count found, $rr_exp_i expected"
+            if test "$rr_count" -ne 0; then
+              issue_note=true
+            fi
+          fi
+          if $issue_note; then
+            echo "note: rerun with option '-Wcounterexamples' to generate conflict counterexamples"
           fi
         } | sed -e "s/^/$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

tests/counterexample.at

@@ -54,8 +54,8 @@ y: A | A B;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B C
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: A . B C
   Shift derivation
     s
     `-> y         c
@@ -64,15 +64,13 @@ Shift/reduce conflict on token B:
     s
     `-> a       x
         `-> A . `-> B C
-
 input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B C
-  Shift derivation     s -> [ y -> [ A . B ] c -> [ C ] ]
-  Reduce derivation    s -> [ a -> [ A . ] x -> [ B C ] ]
-
+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 ] ]
 input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -96,8 +94,8 @@ bc: B bc C | B C;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B C
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: A . B C
   Shift derivation
     s
     `-> ac
@@ -108,9 +106,8 @@ Shift/reduce conflict on token B:
     s
     `-> a       bc
         `-> A . `-> B C
-
-Shift/reduce conflict on token B:
-  Example              A A . B B C C
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: A A . B B C C
   Shift derivation
     s
     `-> ac
@@ -124,20 +121,17 @@ Shift/reduce conflict on token B:
     `-> a             bc
         `-> A a       `-> B bc      C
               `-> A .       `-> B C
-
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B C
-  Shift derivation     s -> [ ac -> [ A ac -> [ b -> [ . B ] ] C ] ]
-  Reduce derivation    s -> [ a -> [ A . ] bc -> [ B C ] ]
-
-Shift/reduce conflict on token B:
-  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: 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 ] ]
+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 ] ]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -162,8 +156,8 @@ xby: B | X xby Y;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: A . B
   Shift derivation
     s
     `-> A xby
@@ -173,16 +167,15 @@ Shift/reduce conflict on token B:
     `-> ax          by
         `-> A x     `-> B y
               `-> .       `-> %empty
-
-Shift/reduce conflict on token B:
-  First example        A X . B Y $end
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  First example: A X . B Y $end
   Shift derivation
     $accept
     `-> s                     $end
         `-> A xby
               `-> X xby     Y
                     `-> . B
-  Second example       A X . B y $end
+  Second example: A X . B y $end
   Reduce derivation
     $accept
     `-> s                             $end
@@ -190,21 +183,18 @@ Shift/reduce conflict on token B:
             `-> A x           `-> B y
                   `-> X x
                         `-> .
-
 input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              A . B
-  Shift derivation     s -> [ A xby -> [ . B ] ]
-  Reduce derivation    s -> [ ax -> [ A x -> [ . ] ] by -> [ B y -> [ ] ] ]
-
-Shift/reduce conflict on token B:
-  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: 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 -> [ ] ] ]
+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 ]
 input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -229,31 +219,29 @@ bc: B C;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token C:
-  First example        B . C $end
+input.y: warning: shift/reduce conflict on token C [-Wcounterexamples]
+  First example: B . C $end
   Shift derivation
     $accept
     `-> g                 $end
         `-> x
             `-> bc
                 `-> B . C
-  Second example       B . C D $end
+  Second example: B . C D $end
   Reduce derivation
     $accept
     `-> g                       $end
         `-> x
             `-> b       cd
                 `-> B . `-> C D
-
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token C:
-  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: 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 ]
 input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -276,15 +264,15 @@ y: A A B;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token A:
-  First example        A . A B $end
+input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
+  First example: A . A B $end
   Shift derivation
     $accept
     `-> s                   $end
         `-> t
             `-> y
                 `-> A . A B
-  Second example       A . A $end
+  Second example: A . A $end
   Reduce derivation
     $accept
     `-> s                             $end
@@ -292,15 +280,13 @@ Shift/reduce conflict on token A:
             `-> t           `-> x
                 `-> x           `-> A
                     `-> A .
-
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token A:
-  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 ]
-
+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 ]
 ]])
 
 AT_CLEANUP
@@ -327,8 +313,8 @@ y: Y;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
-Shift/reduce conflict on token A:
-  Example              b . A X X Y
+input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
+  Example: b . A X X Y
   Shift derivation
     a
     `-> s
@@ -339,35 +325,31 @@ Shift/reduce conflict on token A:
     `-> r       t
         `-> b . `-> A x     xy
                       `-> X `-> X Y
-
-Shift/reduce conflict on token X:
-  First example        A X . X
+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
+  Second example: X . X xy
   Reduce derivation
     a
     `-> x       t
         `-> X . `-> 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]
 ]],
 [[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
-Shift/reduce conflict on token A:
-  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 ] ] ]
-
-Shift/reduce conflict on token X:
-  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: 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 ] ] ]
+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 ] ]
 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]
 ]])
@@ -389,24 +371,22 @@ b : A | b;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
-Reduce/reduce conflict on token $end:
-  Example              A b .
-  First derivation
+input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
+  Example: A b .
+  First reduce derivation
     a
     `-> A b .
-  Second derivation
+  Second reduce derivation
     a
     `-> A b
           `-> b .
-
 input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
-Reduce/reduce conflict on token $end:
-  Example              A b .
-  First derivation     a -> [ A b . ]
-  Second derivation    a -> [ A b -> [ b . ] ]
-
+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 . ] ]
 input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -428,29 +408,27 @@ b: D;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on tokens A, C:
-  First example        D . A $end
-  First derivation
+input.y: warning: reduce/reduce conflict on tokens A, C [-Wcounterexamples]
+  First example: D . A $end
+  First reduce derivation
     $accept
     `-> s             $end
         `-> a       A
             `-> D .
-  Second example       B D . A $end
-  Second derivation
+  Second example: B D . A $end
+  Second reduce derivation
     $accept
     `-> s               $end
         `-> B b       A
               `-> D .
-
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on tokens A, C:
-  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 ]
-
+input.y: warning: reduce/reduce conflict on tokens A, C [-Wcounterexamples]
+  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]
 ]])
 
@@ -472,31 +450,29 @@ i: X | i J K;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token J:
+input.y: warning: shift/reduce conflict on token J [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        H i . J K $end
+  First example: H i . J K $end
   Shift derivation
     $accept
     `-> a                 $end
         `-> H i
               `-> i . J K
-  Second example       H i . J $end
+  Second example: H i . J $end
   Reduce derivation
     $accept
     `-> s               $end
         `-> a         J
             `-> H i .
-
 input.y:4.4-6: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token J:
+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]
 ]])
 
@@ -522,8 +498,8 @@ b: A B C | A B D;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              N A . B C
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: N A . B C
   Shift derivation
     s
     `-> n
@@ -534,9 +510,8 @@ Shift/reduce conflict on token B:
     `-> n               C
         `-> N a       B
               `-> A .
-
-Shift/reduce conflict on token B:
-  Example              N N A . B D C
+input.y: warning: shift/reduce conflict on token B [-Wcounterexamples]
+  Example: N N A . B D C
   Shift derivation
     s
     `-> n
@@ -549,20 +524,17 @@ Shift/reduce conflict on token B:
         `-> N n               D
               `-> N a       B
                     `-> A .
-
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token B:
-  Example              N A . B C
-  Shift derivation     s -> [ n -> [ N b -> [ A . B C ] ] ]
-  Reduce derivation    s -> [ n -> [ N a -> [ A . ] B ] C ]
-
-Shift/reduce conflict on token B:
-  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: 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 ]
+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 ]
 input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -589,48 +561,44 @@ C : A c A;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on tokens b, c:
-  Example              B . b c
-  First derivation
+input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
+  Example: B . b c
+  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
               `-> B                        `-> %empty
                   `-> A     b A
                       `-> .   `-> %empty
-
-Reduce/reduce conflict on tokens b, c:
-  Example              C . c b
-  First derivation
+input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
+  Example: C . c b
+  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
               `-> C                        `-> %empty
                   `-> A     c A
                       `-> .   `-> %empty
-
 ]],
 [[input.y: warning: 4 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on tokens b, c:
-  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 -> [ ] ] ]
-
-Reduce/reduce conflict on tokens b, c:
-  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 -> [ ] ] ]
-
+input.y: warning: reduce/reduce conflict on tokens b, c [-Wcounterexamples]
+  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 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
@@ -653,64 +621,61 @@ d : a | c A | d;
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on token A:
-  First example        . c A A $end
-  First derivation
+input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
+  First example: . c A A $end
+  First reduce derivation
     $accept
     `-> a                   $end
         `-> b     d
             `-> . `-> c A A
-  Second example       . c A A $end
-  Second derivation
+  Second example: . c A A $end
+  Second reduce derivation
     $accept
     `-> a                   $end
         `-> c     d
             `-> . `-> c A A
-
-Reduce/reduce conflict on token A:
+input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        b . c A A $end
-  First derivation
+  First example: b . c A A $end
+  First reduce derivation
     $accept
     `-> a                             $end
         `-> b d
               `-> a
                   `-> b     d
                       `-> . `-> c A A
-  Second example       b . A $end
-  Second derivation
+  Second example: b . A $end
+  Second reduce derivation
     $accept
     `-> a                 $end
         `-> b d
               `-> c     A
                   `-> .
-
-Reduce/reduce conflict on token A:
+input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        c . c A A $end
-  First derivation
+  First example: c . c A A $end
+  First reduce derivation
     $accept
     `-> a                             $end
         `-> c d
               `-> a
                   `-> b     d
                       `-> . `-> c A A
-  Second example       c . A $end
-  Second derivation
+  Second example: c . A $end
+  Second reduce derivation
     $accept
     `-> a                 $end
         `-> c d
               `-> c     A
                   `-> .
-
-Shift/reduce conflict on token A:
+input.y: warning: shift/reduce conflict on token A [-Wcounterexamples]
 time limit exceeded: XXX
-  First example        b c . A
+  First example: b c . A
   Shift derivation
     a
     `-> b d
           `-> c . A
-  Second example       b c . c A A $end
+  Second example: b c . c A A $end
   Reduce derivation
     $accept
     `-> a                                       $end
@@ -720,10 +685,9 @@ time limit exceeded: XXX
                         `-> a
                             `-> b     d
                                 `-> . `-> c A A
-
-Reduce/reduce conflict on token A:
-  First example        b c . c A A $end
-  First derivation
+input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
+  First example: b c . c A A $end
+  First reduce derivation
     $accept
     `-> a                                       $end
         `-> b d
@@ -732,8 +696,8 @@ Reduce/reduce conflict on token A:
                         `-> a
                             `-> b     d
                                 `-> . `-> c A A
-  Second example       b c . A $end
-  Second derivation
+  Second example: b c . A $end
+  Second reduce derivation
     $accept
     `-> a                           $end
         `-> b d
@@ -741,14 +705,13 @@ Reduce/reduce conflict on token A:
                   `-> c d
                         `-> c     A
                             `-> .
-
-Shift/reduce conflict on token A:
-  First example        b c . A
+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
+  Second example: b c . A $end
   Reduce derivation
     $accept
     `-> a                           $end
@@ -757,81 +720,70 @@ Shift/reduce conflict on token A:
                   `-> c d
                         `-> c     A
                             `-> .
-
-Reduce/reduce conflict on token $end:
-  Example              b d .
-  First derivation
+input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
+  Example: b d .
+  First reduce derivation
     a
     `-> b d .
-  Second derivation
+  Second reduce derivation
     a
     `-> b d
           `-> d .
-
-Reduce/reduce conflict on token $end:
-  Example              c d .
-  First derivation
+input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
+  Example: c d .
+  First reduce derivation
     a
     `-> c d .
-  Second derivation
+  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]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
 input.y: warning: 6 reduce/reduce conflicts [-Wconflicts-rr]
-Reduce/reduce conflict on token A:
-  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 ]
-
-Reduce/reduce conflict on token A:
+input.y: warning: reduce/reduce conflict on token A [-Wcounterexamples]
+  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 ]
-
-Reduce/reduce conflict on token A:
+  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 ]
-
-Shift/reduce conflict on token A:
+  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 ]
-
-Reduce/reduce conflict on token A:
-  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 ]
-
-Shift/reduce conflict on token A:
-  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 ]
-
-Reduce/reduce conflict on token $end:
-  Example              b d .
-  First derivation     a -> [ b d . ]
-  Second derivation    a -> [ b d -> [ d . ] ]
-
-Reduce/reduce conflict on token $end:
-  Example              c d .
-  First derivation     a -> [ c d . ]
-  Second derivation    a -> [ c d -> [ d . ] ]
-
+  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 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 ]
+input.y: warning: reduce/reduce conflict on token $end [-Wcounterexamples]
+  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 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]
 ]])
@@ -857,8 +809,8 @@ i: %empty | i J;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token J:
-  Example              H i J . J J
+input.y: warning: shift/reduce conflict on token J [-Wcounterexamples]
+  Example: H i J . J J
   Shift derivation
     s
     `-> a             J
@@ -868,15 +820,13 @@ Shift/reduce conflict on token J:
     `-> a
         `-> H i         J J
               `-> i J .
-
 input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token 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: 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 ] ]
 input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -903,8 +853,8 @@ d: D;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token D:
-  Example              A a . D
+input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
+  Example: A a . D
   Shift derivation
     s
     `-> A a d
@@ -915,14 +865,12 @@ Shift/reduce conflict on token D:
             `-> b         `-> D
                 `-> c
                     `-> .
-
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token D:
-  Example              A a . D
-  Shift derivation     s -> [ A a d -> [ . D ] ]
-  Reduce derivation    s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] ]
-
+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 ] ]
 ]])
 
 AT_CLEANUP
@@ -947,14 +895,14 @@ d: D;
 
 AT_BISON_CHECK_CEX(
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token D:
-  First example        A a . D $end
+input.y: warning: shift/reduce conflict on token D [-Wcounterexamples]
+  First example: A a . D $end
   Shift derivation
     $accept
     `-> s               $end
         `-> A a d
                 `-> . D
-  Second example       A a . D E $end
+  Second example: A a . D E $end
   Reduce derivation
     $accept
     `-> s                             $end
@@ -962,15 +910,13 @@ Shift/reduce conflict on token D:
                 `-> b         `-> D
                     `-> c
                         `-> .
-
 ]],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-Shift/reduce conflict on token D:
-  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 ]
-
+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 ]
 ]])
 
 AT_CLEANUP

tests/diagnostics.at

@@ -51,7 +51,7 @@ if $EGREP ['\^M|\\[0-9][0-9][0-9]'] input.y experr >/dev/null; then
   AT_PERL_REQUIRE([-pi -e 's{\^M}{\r}g;s{\\(\d{3}|.)}{$v = $[]1; $v =~ /\A\d+\z/ ? chr($v) : $v}ge' input.y experr])
 fi
 
-AT_CHECK([LC_ALL="$locale" $5 bison -fcaret --color=debug -Wall,cex input.y], [$3], [], [experr])
+AT_CHECK(AT_SET_ENV [LC_ALL="$locale" $5 bison -fcaret --color=debug -Wall,cex input.y], [$3], [], [experr])
 
 # When no style, same messages, but without style.
 # Except for the second display of the counterexample,
@@ -68,7 +68,7 @@ AT_PERL_REQUIRE([-pi -e '
 # Cannot use AT_BISON_CHECK easily as we need to change the
 # environment.
 # FIXME: Enhance AT_BISON_CHECK.
-AT_CHECK([LC_ALL="$locale" $5 bison -fcaret -Wall,cex input.y], [$3], [], [experr])
+AT_CHECK(AT_SET_ENV [LC_ALL="$locale" $5 bison -fcaret -Wall,cex input.y], [$3], [], [experr])
 
 
 AT_BISON_OPTION_POPDEFS
@@ -535,54 +535,50 @@ exp
 ]],
 [1],
 [[input.y: <error>error:</error> shift/reduce conflicts: 4 found, 0 expected
-Shift/reduce conflict on token "+":
-  Example              <cex-0><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
+input.y: <warning>warning:</warning> shift/reduce conflict on token "+" [<warning>-Wcounterexamples</warning>]
+  Example: <cex-0><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
   Shift derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-leaf>exp</cex-leaf><cex-leaf> "+"</cex-leaf><cex-1><cex-step> exp</cex-step></cex-1></cex-step></cex-0>
     <cex-1><cex-step>          ↳ <cex-leaf>exp</cex-leaf><cex-dot> •</cex-dot><cex-leaf> "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-1>
-  Example              <cex-0><cex-1><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
+  Example: <cex-0><cex-1><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
   Reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-1><cex-step>exp</cex-step></cex-1><cex-leaf>             "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-0>
     <cex-1><cex-step>  ↳ <cex-leaf>exp</cex-leaf><cex-leaf> "+"</cex-leaf><cex-leaf> exp</cex-leaf><cex-dot> •</cex-dot></cex-step></cex-1>
-
-Shift/reduce conflict on token "else":
-  Example              <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
+input.y: <warning>warning:</warning> shift/reduce conflict on token "else" [<warning>-Wcounterexamples</warning>]
+  Example: <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
   Shift derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-1><cex-step> exp</cex-step></cex-1></cex-step></cex-0>
     <cex-1><cex-step>                  ↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-leaf> exp</cex-leaf><cex-dot> •</cex-dot><cex-leaf> "else"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-1>
-  Example              <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
+  Example: <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
   Reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-1><cex-step> exp</cex-step></cex-1><cex-leaf>                     "else"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-0>
     <cex-1><cex-step>                  ↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-leaf> exp</cex-leaf><cex-dot> •</cex-dot></cex-step></cex-1>
-
-Shift/reduce conflict on token "+":
-  Example              <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
+input.y: <warning>warning:</warning> shift/reduce conflict on token "+" [<warning>-Wcounterexamples</warning>]
+  Example: <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
   Shift derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-1><cex-step> exp</cex-step></cex-1></cex-step></cex-0>
     <cex-1><cex-step>                  ↳ <cex-leaf>exp</cex-leaf><cex-dot> •</cex-dot><cex-leaf> "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-1>
-  Example              <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
+  Example: <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
   Reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-1><cex-step>exp</cex-step></cex-1><cex-leaf>                     "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-0>
     <cex-1><cex-step>  ↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-leaf> exp</cex-leaf><cex-dot> •</cex-dot></cex-step></cex-1>
-
-Shift/reduce conflict on token "+":
-  Example              <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
+input.y: <warning>warning:</warning> shift/reduce conflict on token "+" [<warning>-Wcounterexamples</warning>]
+  Example: <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
   Shift derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "else"</cex-leaf><cex-1><cex-step> exp</cex-step></cex-1></cex-step></cex-0>
     <cex-1><cex-step>                             ↳ <cex-leaf>exp</cex-leaf><cex-dot> •</cex-dot><cex-leaf> "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-1>
-  Example              <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
+  Example: <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
   Reduce derivation
     <cex-0><cex-step>exp</cex-step></cex-0>
     <cex-0><cex-step>↳ <cex-1><cex-step>exp</cex-step></cex-1><cex-leaf>                                "+"</cex-leaf><cex-leaf> exp</cex-leaf></cex-step></cex-0>
     <cex-1><cex-step>  ↳ <cex-leaf>"if"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "then"</cex-leaf><cex-leaf> exp</cex-leaf><cex-leaf> "else"</cex-leaf><cex-leaf> exp</cex-leaf><cex-dot> •</cex-dot></cex-step></cex-1>
-
 ]])
 
 
@@ -621,9 +617,9 @@ 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
-Reduce/reduce conflict on token "X":
-  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 derivation
+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>
     <cex-0><cex-step>↳ <cex-1><cex-step>x1</cex-step></cex-1><cex-4><cex-step>          e1</cex-step></cex-4><cex-5><cex-step>  foo1</cex-step></cex-5><cex-12><cex-step>                      x1</cex-step></cex-12></cex-step></cex-0>
     <cex-1><cex-step>  ↳ <cex-2><cex-step>x2</cex-step></cex-2></cex-step></cex-1><cex-4><cex-step>        ↳ ε</cex-step></cex-4><cex-5><cex-step> ↳ <cex-6><cex-step>foo2</cex-step></cex-6></cex-step></cex-5><cex-12><cex-step>                    ↳ <cex-13><cex-step>x2</cex-step></cex-13></cex-step></cex-12>
@@ -632,8 +628,8 @@ Reduce/reduce conflict on token "X":
     <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>
-  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 derivation
+  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>
     <cex-0><cex-step>↳ <cex-1><cex-step>y1</cex-step></cex-1><cex-4><cex-step>          e2</cex-step></cex-4><cex-5><cex-step>  bar1</cex-step></cex-5><cex-12><cex-step>                      y1</cex-step></cex-12></cex-step></cex-0>
     <cex-1><cex-step>  ↳ <cex-2><cex-step>y2</cex-step></cex-2></cex-step></cex-1><cex-4><cex-step>        ↳ ε</cex-step></cex-4><cex-5><cex-step> ↳ <cex-6><cex-step>bar2</cex-step></cex-6></cex-step></cex-5><cex-12><cex-step>                    ↳ <cex-13><cex-step>y2</cex-step></cex-13></cex-step></cex-12>
@@ -642,7 +638,6 @@ Reduce/reduce conflict on token "X":
     <cex-8><cex-step>                        ↳ <cex-9><cex-step>y2</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>y3</cex-step></cex-10></cex-step></cex-9>
     <cex-10><cex-step>                            ↳ <cex-leaf>"X"</cex-leaf></cex-step></cex-10>
-
 input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with option '--update'. [<warning>-Wother</warning>]
 ]])
 

tests/existing.at

@@ -434,7 +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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 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]
@@ -1419,7 +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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 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]

tests/glr-regression.at

@@ -89,7 +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]
+glr-regr1.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr1])
 AT_PARSER_CHECK([[glr-regr1 BPBPB]], 0,
@@ -214,7 +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]
+glr-regr2a.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr2a])
 
@@ -350,7 +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]
+glr-regr3.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr3])
 
@@ -447,7 +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]
+glr-regr4.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr4])
 
@@ -505,7 +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]
+glr-regr5.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr5])
 
@@ -555,7 +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]
+glr-regr6.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr6])
 
@@ -646,7 +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]
+glr-regr7.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr7])
 
@@ -737,7 +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]
+glr-regr8.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr8])
 
@@ -819,7 +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]
+glr-regr9.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr9])
 
@@ -877,7 +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]
+glr-regr10.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr10])
 
@@ -937,7 +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]
+glr-regr11.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr11])
 
@@ -1060,7 +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]
+glr-regr12.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr12])
 
@@ -1392,7 +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]
+glr-regr14.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr14])
 
@@ -1487,7 +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]
+glr-regr15.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr15])
 
@@ -1549,7 +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]
+glr-regr16.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr16])
 
@@ -1625,7 +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]
+glr-regr17.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([glr-regr17])
 
@@ -1719,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]])
 AT_COMPILE([input])
 

tests/input.at

@@ -2887,7 +2887,6 @@ 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]
 ]])
 

tests/local.at

@@ -1199,7 +1199,7 @@ m4_define([AT_BISON_CHECK_XML],
 # The testsuite verbose output, at least, will be incorrect, but nothing may
 # fail to make sure you notice.
 m4_define([AT_SET_ENV_IF],
-[[[COLUMNS=1000; export COLUMNS;]] m4_null_if($1, [], [[[VALGRIND_OPTS="$VALGRIND_OPTS --leak-check=summary --show-reachable=no"; export VALGRIND_OPTS; ]]])])
+[[[COLUMNS=1000; export COLUMNS; NO_TERM_HYPERLINKS=1; export NO_TERM_HYPERLINKS;]] m4_null_if($1, [], [[[VALGRIND_OPTS="$VALGRIND_OPTS --leak-check=summary --show-reachable=no"; export VALGRIND_OPTS; ]]])])
 
 
 # AT_SET_ENV

tests/reduce.at

@@ -1300,7 +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]
+input.y: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 ]], [])],
 
 dnl TABLES

tests/report.at

@@ -1537,8 +1537,8 @@ exp
 AT_CHECK([LC_ALL="$locale" bison -fno-caret -o input.cc -rall -Wcex --graph=input.gv --xml input.y], [], [],
 [[input.y: warning: 3 shift/reduce conflicts [-Wconflicts-sr]
 input.y: warning: 3 reduce/reduce conflicts [-Wconflicts-rr]
-Shift/reduce conflict on token "⊕":
-  Example              exp "+" exp • "⊕" exp
+input.y: warning: shift/reduce conflict on token "⊕" [-Wcounterexamples]
+  Example: exp "+" exp • "⊕" exp
   Shift derivation
     exp
     ↳ exp "+" exp
@@ -1547,18 +1547,16 @@ Shift/reduce conflict on token "⊕":
     exp
     ↳ exp             "⊕" exp
       ↳ exp "+" exp •
-
-Reduce/reduce conflict on tokens $end, "+", "⊕":
-  Example              exp "+" exp •
-  First derivation
+input.y: warning: reduce/reduce conflict on tokens $end, "+", "⊕" [-Wcounterexamples]
+  Example: exp "+" exp •
+  First reduce derivation
     exp
     ↳ exp "+" exp •
-  Second derivation
+  Second reduce derivation
     exp
     ↳ exp "+" exp •
-
-Shift/reduce conflict on token "⊕":
-  Example              exp "+" exp • "⊕" exp
+input.y: warning: shift/reduce conflict on token "⊕" [-Wcounterexamples]
+  Example: exp "+" exp • "⊕" exp
   Shift derivation
     exp
     ↳ exp "+" exp
@@ -1567,9 +1565,8 @@ Shift/reduce conflict on token "⊕":
     exp
     ↳ exp             "⊕" exp
       ↳ exp "+" exp •
-
-Shift/reduce conflict on token "⊕":
-  Example              exp "⊕" exp • "⊕" exp
+input.y: warning: shift/reduce conflict on token "⊕" [-Wcounterexamples]
+  Example: exp "⊕" exp • "⊕" exp
   Shift derivation
     exp
     ↳ exp "⊕" exp
@@ -1578,9 +1575,8 @@ Shift/reduce conflict on token "⊕":
     exp
     ↳ exp             "⊕" exp
       ↳ exp "⊕" exp •
-
-Shift/reduce conflict on token "+":
-  Example              exp "⊕" exp • "+" exp
+input.y: warning: shift/reduce conflict on token "+" [-Wcounterexamples]
+  Example: exp "⊕" exp • "+" exp
   Shift derivation
     exp
     ↳ exp "⊕" exp
@@ -1589,9 +1585,8 @@ Shift/reduce conflict on token "+":
     exp
     ↳ exp             "+" exp
       ↳ exp "⊕" exp •
-
-Shift/reduce conflict on token "+":
-  Example              exp "⊕" exp • "+" exp
+input.y: warning: shift/reduce conflict on token "+" [-Wcounterexamples]
+  Example: exp "⊕" exp • "+" exp
   Shift derivation
     exp
     ↳ exp "⊕" exp
@@ -1600,7 +1595,6 @@ Shift/reduce conflict on token "+":
     exp
     ↳ exp             "+" exp
       ↳ exp "⊕" exp •
-
 input.y:6.3-13: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
@@ -1745,10 +1739,10 @@ State 7
 
     Conflict between rule 2 and token "+" resolved as reduce (%left "+").
 
-    Shift/reduce conflict on token "⊕":
+    shift/reduce conflict on token "⊕":
         2 exp: exp "+" exp •
         1 exp: exp • "⊕" exp
-      Example                  exp "+" exp • "⊕" exp
+      Example: exp "+" exp • "⊕" exp
       Shift derivation
         exp
         ↳ exp "+" exp
@@ -1758,21 +1752,21 @@ State 7
         ↳ exp             "⊕" exp
           ↳ exp "+" exp •
 
-    Reduce/reduce conflict on tokens $end, "+", "⊕":
+    reduce/reduce conflict on tokens $end, "+", "⊕":
         2 exp: exp "+" exp •
         3 exp: exp "+" exp •
-      Example                  exp "+" exp •
-      First derivation
+      Example: exp "+" exp •
+      First reduce derivation
         exp
         ↳ exp "+" exp •
-      Second derivation
+      Second reduce derivation
         exp
         ↳ exp "+" exp •
 
-    Shift/reduce conflict on token "⊕":
+    shift/reduce conflict on token "⊕":
         3 exp: exp "+" exp •
         1 exp: exp • "⊕" exp
-      Example                  exp "+" exp • "⊕" exp
+      Example: exp "+" exp • "⊕" exp
       Shift derivation
         exp
         ↳ exp "+" exp
@@ -1798,10 +1792,10 @@ State 8
     "⊕"       [reduce using rule 1 (exp)]
     $default  reduce using rule 1 (exp)
 
-    Shift/reduce conflict on token "⊕":
+    shift/reduce conflict on token "⊕":
         1 exp: exp "⊕" exp •
         1 exp: exp • "⊕" exp
-      Example                  exp "⊕" exp • "⊕" exp
+      Example: exp "⊕" exp • "⊕" exp
       Shift derivation
         exp
         ↳ exp "⊕" exp
@@ -1811,10 +1805,10 @@ State 8
         ↳ exp             "⊕" exp
           ↳ exp "⊕" exp •
 
-    Shift/reduce conflict on token "+":
+    shift/reduce conflict on token "+":
         1 exp: exp "⊕" exp •
         2 exp: exp • "+" exp
-      Example                  exp "⊕" exp • "+" exp
+      Example: exp "⊕" exp • "+" exp
       Shift derivation
         exp
         ↳ exp "⊕" exp
@@ -1824,10 +1818,10 @@ State 8
         ↳ exp             "+" exp
           ↳ exp "⊕" exp •
 
-    Shift/reduce conflict on token "+":
+    shift/reduce conflict on token "+":
         1 exp: exp "⊕" exp •
         3 exp: exp • "+" exp
-      Example                  exp "⊕" exp • "+" exp
+      Example: exp "⊕" exp • "+" exp
       Shift derivation
         exp
         ↳ exp "⊕" exp

tests/sets.at

@@ -285,7 +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: note: rerun with option '-Wcounterexamples' to generate conflict counterexamples
 input.y:2.14-17: warning: rule useless in parser due to conflicts [-Wother]
     2 | expr: term | term | term | term | term | term
       |              ^~~~