RFC: diagnostics: display suggested update after the caret-info

[Akim Demaille]

This commit changes the warning from:

> foo.yy:1.5-18: warning: deprecated directive, use '%define parse.error 
> verbose' [-Wdeprecated]
>  %error-verbose
>  ^~~~~~~~~~~~~~

to:

> foo.yy:1.5-18: warning: deprecated directive [-Wdeprecated]
>  %error-verbose
>  ^~~~~~~~~~~~~~
>  %define parse.error verbose

For the records, when caret-errors are disabled, we have (independently of this 
proposed change):

> foo.yy:1.1-14: warning: deprecated directive: '%error-verbose', use '%define 
> parse.error verbose' [-Wdeprecated]

I mentioned this here:

https://lists.gnu.org/archive/html/bison-patches/2019-02/msg00080.html


I would really like to know what people think about this change.  TIA!


commit 18ce9615df724fad92bca37a3b843c347abf5222
Author: Akim Demaille <address@hidden>
Date:   Sat Feb 16 08:01:34 2019 +0100

    diagnostics: display suggested update after the caret-info
    
    This commit changes the warning from:
    
        foo.yy:1.5-18: warning: deprecated directive, use '%define parse.error 
verbose' [-Wdeprecated]
         %error-verbose
         ^~~~~~~~~~~~~~
    
    to:
    
        foo.yy:1.5-18: warning: deprecated directive [-Wdeprecated]
         %error-verbose
         ^~~~~~~~~~~~~~
         %define parse.error verbose
    
    The latter consumes less width.
    
    * src/complain.c (deprecated_directive): Implement this change.
    * tests/input.at: Adjust expectations.

diff --git a/src/complain.c b/src/complain.c
index 50f65af5..ddd1541d 100644
--- a/src/complain.c
+++ b/src/complain.c
@@ -390,9 +390,11 @@ void
 deprecated_directive (location const *loc, char const *old, char const *upd)
 {
   if (feature_flag & feature_caret)
-    complain (loc, Wdeprecated,
-              _("deprecated directive, use %s"),
-              quote_n (1, upd));
+    {
+      complain (loc, Wdeprecated,
+                _("deprecated directive"));
+      fprintf (stderr, " %*s%s\n", loc->start.column - 1, "", upd);
+    }
   else
     complain (loc, Wdeprecated,
               _("deprecated directive: %s, use %s"),
diff --git a/tests/input.at b/tests/input.at
index 7494e46a..1a6f0e56 100644
--- a/tests/input.at
+++ b/tests/input.at
@@ -1998,21 +1998,26 @@ AT_DATA([[input.y]],
 start: %empty;
 ]])
 AT_BISON_CHECK([[-fcaret input.y]], [1], [],
-[[input.y:1.1-26: warning: deprecated directive, use '%define api.push-pull 
both' [-Wdeprecated]
+[[input.y:1.1-26: warning: deprecated directive [-Wdeprecated]
  %define api.push_pull both
  ^~~~~~~~~~~~~~~~~~~~~~~~~~
-input.y:2.1-40: warning: deprecated directive, use '%define 
lr.keep-unreachable-state maybe' [-Wdeprecated]
+ %define api.push-pull both
+input.y:2.1-40: warning: deprecated directive [-Wdeprecated]
  %define lr.keep_unreachable_states maybe
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-input.y:3.1-23: warning: deprecated directive, use '%define api.namespace 
{foo}' [-Wdeprecated]
+ %define lr.keep-unreachable-state maybe
+input.y:3.1-23: warning: deprecated directive [-Wdeprecated]
  %define namespace "foo"
  ^~~~~~~~~~~~~~~~~~~~~~~
-input.y:4.1-15: warning: deprecated directive, use '%define api.value.type 
variant' [-Wdeprecated]
+ %define api.namespace {foo}
+input.y:4.1-15: warning: deprecated directive [-Wdeprecated]
  %define variant
  ^~~~~~~~~~~~~~~
-input.y:5.1-34: warning: deprecated directive, use '%define api.parser.class 
{parser}' [-Wdeprecated]
+ %define api.value.type variant
+input.y:5.1-34: warning: deprecated directive [-Wdeprecated]
  %define parser_class_name {parser}
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ %define api.parser.class {parser}
 input.y:2.1-40: error: invalid value for %define Boolean variable 
'lr.keep-unreachable-state'
  %define lr.keep_unreachable_states maybe
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~