[PATCH 2/8] diagnostics: no longer pretty-print rules in error messages, carets suffice

[Akim Demaille]

* src/gram.c (grammar_rules_useless_report): Let -fcaret handle the
pretty-printing of the guilty rules.
(rule_print): Inline in its only use.
* tests/conflicts.at, tests/existing.at, tests/reduce.at,
* tests/regression.at: Adjust.
* NEWS: Document.
---
 NEWS                | 23 +++++++++++++++++++++++
 src/gram.c          | 33 ++++++---------------------------
 tests/conflicts.at  | 30 +++++++++++++++---------------
 tests/existing.at   |  2 +-
 tests/reduce.at     | 38 +++-----------------------------------
 tests/regression.at |  4 ++--
 6 files changed, 50 insertions(+), 80 deletions(-)

diff --git a/NEWS b/NEWS
index 5b9a6e8..9489c51 100644
--- a/NEWS
+++ b/NEWS
@@ -58,6 +58,29 @@ GNU Bison NEWS
   activated by default.  The old format can still be used by invoking Bison
   with -fno-caret (or -fnone).
 
+  Some error messages that reproduced excerpts of the grammar are now using
+  the caret information only.  For instance on:
+
+    %%
+    exp: 'a' | 'a';
+
+  Bison 2.7 reports:
+
+    in.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+    in.y:2.12-14: warning: rule useless in parser due to conflicts: exp: 'a' 
[-Wother]
+
+  Now bison reports:
+
+    in.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+    in.y:2.12-14: warning: rule useless in parser due to conflicts [-Wother]
+     exp: 'a' | 'a';
+                ^^^
+
+  and "bison -fno-caret" reports:
+
+    in.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
+    in.y:2.12-14: warning: rule useless in parser due to conflicts [-Wother]
+
 *** Enhancements of the -Werror option
 
   The -Werror=CATEGORY option is now recognized, and will treat specified
diff --git a/src/gram.c b/src/gram.c
index 6cbe622..c0177df 100644
--- a/src/gram.c
+++ b/src/gram.c
@@ -125,13 +125,6 @@ rule_rhs_print_xml (rule const *r, FILE *out, int level)
     }
 }
 
-static void
-rule_print (rule const *r, FILE *out)
-{
-  fprintf (out, "%s:", r->lhs->tag);
-  rule_rhs_print (r, out);
-}
-
 void
 ritem_print (FILE *out)
 {
@@ -289,8 +282,8 @@ grammar_dump (FILE *out, const char *title)
     rule_number r;
     for (r = 0; r < nrules + nuseless_productions; r++)
       {
-        fprintf (out, "%-5d  ", r);
-        rule_print (&rules[r], out);
+        fprintf (out, "%-5d  %s:", r, rules[r].lhs->tag);
+        rule_rhs_print (&rules[r], out);
         fprintf (out, "\n");
       }
   }
@@ -300,24 +293,10 @@ grammar_dump (FILE *out, const char *title)
 void
 grammar_rules_useless_report (const char *message)
 {
-  warnings w = Wother;
-  if (warnings_flag & w)
-    {
-      rule_number r;
-      for (r = 0; r < nrules ; ++r)
-        if (!rules[r].useful)
-          {
-            if (feature_flag & feature_caret)
-              complain (&rules[r].location, w, "%s", message);
-            else
-              {
-                complain (&rules[r].location, w | silent, "%s: ", message);
-                rule_print (&rules[r], stderr);
-                warnings_print_categories (w);
-                fprintf (stderr, "\n");
-              }
-          }
-    }
+  rule_number r;
+  for (r = 0; r < nrules ; ++r)
+    if (!rules[r].useful)
+      complain (&rules[r].location, Wother, "%s", message);
 }
 
 void
diff --git a/tests/conflicts.at b/tests/conflicts.at
index 2d47fc6..9f7d59f 100644
--- a/tests/conflicts.at
+++ b/tests/conflicts.at
@@ -192,7 +192,7 @@ e: 'e' | /* Nothing. */;
 ]])
 
 AT_BISON_CHECK([-o input.c input.y], 0, [],
-[[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty 
*/ [-Wother]
+[[input.y:4.9: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 AT_BISON_CHECK([-fcaret -o input.c input.y], 0, [],
@@ -920,7 +920,7 @@ cond:
 
 AT_BISON_CHECK([-o input.c input.y], 0, [],
 [[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
-input.y:12.3-18: warning: rule useless in parser due to conflicts: cond: cond 
"then" cond [-Wother]
+input.y:12.3-18: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 AT_CLEANUP
@@ -964,7 +964,7 @@ id : '0';
 
 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 [[input.y: warning: 1 reduce/reduce conflict [-Wconflicts-rr]
-input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0' 
[-Wother]
+input.y:4.6-8: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 # Check the contents of the report.
@@ -1284,13 +1284,13 @@ 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:12.5-20: warning: rule useless in parser due to conflicts: 
resolved_conflict: 'a' unreachable1 [-Wother]
-input.y:20.5-20: warning: rule useless in parser due to conflicts: 
unreachable1: 'a' unreachable2 [-Wother]
-input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: 
/* empty */ [-Wother]
-input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: 
/* empty */ [-Wother]
-input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: 
/* empty */ [-Wother]
-input.y:31.5-7: warning: rule useless in parser due to conflicts: 
reported_conflicts: 'a' [-Wother]
-input.y:32.4: warning: rule useless in parser due to conflicts: 
reported_conflicts: /* empty */ [-Wother]
+input.y:12.5-20: warning: rule useless in parser due to conflicts [-Wother]
+input.y:20.5-20: warning: rule useless in parser due to conflicts [-Wother]
+input.y:21.4: warning: rule useless in parser due to conflicts [-Wother]
+input.y:25.13: warning: rule useless in parser due to conflicts [-Wother]
+input.y:25.16: warning: rule useless in parser due to conflicts [-Wother]
+input.y:31.5-7: warning: rule useless in parser due to conflicts [-Wother]
+input.y:32.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 AT_CHECK([[cat input.output]], 0,
@@ -1437,10 +1437,10 @@ 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:22.4: warning: rule useless in parser due to conflicts: 
unreachable1: /* empty */ [-Wother]
-input-keep.y:26.16: warning: rule useless in parser due to conflicts: 
unreachable2: /* empty */ [-Wother]
-input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: 
reported_conflicts: 'a' [-Wother]
-input-keep.y:33.4: warning: rule useless in parser due to conflicts: 
reported_conflicts: /* empty */ [-Wother]
+input-keep.y:22.4: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:26.16: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:32.5-7: warning: rule useless in parser due to conflicts [-Wother]
+input-keep.y:33.4: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 AT_CLEANUP
@@ -1620,7 +1620,7 @@ 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:3.12-14: warning: rule useless in parser due to conflicts: exp: 'a' 
[-Wother]
+2.y:3.12-14: warning: rule useless in parser due to conflicts [-Wother]
 ]])
 
 AT_CLEANUP
diff --git a/tests/existing.at b/tests/existing.at
index 215993c..cd80c50 100644
--- a/tests/existing.at
+++ b/tests/existing.at
@@ -2001,7 +2001,7 @@ dnl without being followed by "of".)
 [[VARIABLE, '=', LABEL, LEFT, DOT_X]],
 
 dnl BISON-STDERR
-[[input.y:471.11-48: warning: rule useless in parser due to conflicts: path: 
ORDINAL LAST object_type relative_path [-Wother]
+[[input.y:471.11-48: warning: rule useless in parser due to conflicts [-Wother]
 input.y:19.8-12: warning: useless associativity for LABEL, use %precedence 
[-Wprecedence]
 input.y:20.8-15: warning: useless associativity for VARIABLE, use %precedence 
[-Wprecedence]
 input.y:21.8-13: warning: useless associativity for NUMBER, use %precedence 
[-Wprecedence]
diff --git a/tests/reduce.at b/tests/reduce.at
index a5fd1ca..c5e4fda 100644
--- a/tests/reduce.at
+++ b/tests/reduce.at
@@ -201,28 +201,6 @@ input.y:14.11-13: warning: rule useless in grammar 
[-Wother]
            ^^^
 ]])
 
-AT_BISON_CHECK([[input.y]], 0, [],
-[[input.y: warning: 9 nonterminals useless in grammar [-Wother]
-input.y: warning: 9 rules useless in grammar [-Wother]
-input.y:6.1-8: warning: nonterminal useless in grammar: useless1 [-Wother]
-input.y:7.1-8: warning: nonterminal useless in grammar: useless2 [-Wother]
-input.y:8.1-8: warning: nonterminal useless in grammar: useless3 [-Wother]
-input.y:9.1-8: warning: nonterminal useless in grammar: useless4 [-Wother]
-input.y:10.1-8: warning: nonterminal useless in grammar: useless5 [-Wother]
-input.y:11.1-8: warning: nonterminal useless in grammar: useless6 [-Wother]
-input.y:12.1-8: warning: nonterminal useless in grammar: useless7 [-Wother]
-input.y:13.1-8: warning: nonterminal useless in grammar: useless8 [-Wother]
-input.y:14.1-8: warning: nonterminal useless in grammar: useless9 [-Wother]
-input.y:6.11-13: warning: rule useless in grammar: useless1: '1' [-Wother]
-input.y:7.11-13: warning: rule useless in grammar: useless2: '2' [-Wother]
-input.y:8.11-13: warning: rule useless in grammar: useless3: '3' [-Wother]
-input.y:9.11-13: warning: rule useless in grammar: useless4: '4' [-Wother]
-input.y:10.11-13: warning: rule useless in grammar: useless5: '5' [-Wother]
-input.y:11.11-13: warning: rule useless in grammar: useless6: '6' [-Wother]
-input.y:12.11-13: warning: rule useless in grammar: useless7: '7' [-Wother]
-input.y:13.11-13: warning: rule useless in grammar: useless8: '8' [-Wother]
-input.y:14.11-13: warning: rule useless in grammar: useless9: '9' [-Wother]
-]])
 
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
 [[Nonterminals useless in grammar
@@ -317,16 +295,6 @@ not-reduced.y:17.17-18.63: warning: rule useless in 
grammar [-Wother]
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 ]])
 
-AT_BISON_CHECK([[not-reduced.y]], 0, [],
-[[not-reduced.y: warning: 2 nonterminals useless in grammar [-Wother]
-not-reduced.y: warning: 3 rules useless in grammar [-Wother]
-not-reduced.y:14.1-13: warning: nonterminal useless in grammar: not_reachable 
[-Wother]
-not-reduced.y:11.6-19: warning: nonterminal useless in grammar: non_productive 
[-Wother]
-not-reduced.y:11.6-57: warning: rule useless in grammar: exp: non_productive 
[-Wother]
-not-reduced.y:14.16-56: warning: rule useless in grammar: not_reachable: 
useful [-Wother]
-not-reduced.y:17.17-18.63: warning: rule useless in grammar: non_productive: 
non_productive useless_token [-Wother]
-]])
-
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' not-reduced.output]], 0,
 [[Nonterminals useless in grammar
    not_reachable
@@ -397,9 +365,9 @@ AT_BISON_CHECK([[input.y]], 0, [],
 input.y: warning: 3 rules useless in grammar [-Wother]
 input.y:5.15-25: warning: nonterminal useless in grammar: underivable [-Wother]
 input.y:6.14-24: warning: nonterminal useless in grammar: indirection [-Wother]
-input.y:5.15-25: warning: rule useless in grammar: exp: underivable [-Wother]
-input.y:6.14-24: warning: rule useless in grammar: underivable: indirection 
[-Wother]
-input.y:7.14-24: warning: rule useless in grammar: indirection: underivable 
[-Wother]
+input.y:5.15-25: warning: rule useless in grammar [-Wother]
+input.y:6.14-24: warning: rule useless in grammar [-Wother]
+input.y:7.14-24: warning: rule useless in grammar [-Wother]
 ]])
 
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
diff --git a/tests/regression.at b/tests/regression.at
index 374ac69..544c835 100644
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -1148,8 +1148,8 @@ sr_conflict:
 AT_BISON_OPTION_POPDEFS
 
 AT_BISON_CHECK([[-Wall -o input.c input.y]], [[0]],,
-[[input.y:24.5-19: warning: rule useless in parser due to conflicts: start: 
start [-Wother]
-input.y:28.5-19: warning: rule useless in parser due to conflicts: 
sr_conflict: TK2 "tok alias" [-Wother]
+[[input.y:24.5-19: warning: rule useless in parser due to conflicts [-Wother]
+input.y:28.5-19: warning: rule useless in parser due to conflicts [-Wother]
 input.y:18.7-9: warning: useless precedence and associativity for TK1 
[-Wprecedence]
 ]])
 AT_COMPILE([[input]])
-- 
1.8.1.3