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

[Akim Demaille]

Hi Paul,

> Le 17 févr. 2019 à 21:16, Paul Eggert <address@hidden> a écrit :
> 
> Akim Demaille wrote:
>> 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 find the new diagnostic confusing, as it's not clear to the non-expert what 
> the "%define parse.error verbose" means. The old diagnostic (or the one with 
> caret-errors disabled) is clearer.

Yes, I agree, it was better before.  I tried to have something that
takes less width, but it's also less clear.  For substitutions in the
source, gcc and clang do this:


$ cat /tmp/foo.cc
int my_function() { return 42;}
int main ()
{
  return myfunction();
}


$ clang++-mp-7.0 -Wall /tmp/foo.cc
/tmp/foo.cc:4:10: error: use of undeclared identifier 'myfunction'; did you 
mean 'my_function'?
  return myfunction();
         ^~~~~~~~~~
         my_function
/tmp/foo.cc:1:5: note: 'my_function' declared here
int my_function() { return 42;}
    ^
1 error generated.


$ g++-mp-8 -Wall /tmp/foo.cc
/tmp/foo.cc: In function 'int main()':
/tmp/foo.cc:4:10: error: 'myfunction' was not declared in this scope
   return myfunction();
          ^~~~~~~~~~
/tmp/foo.cc:4:10: note: suggested alternative: 'my_function'
   return myfunction();
          ^~~~~~~~~~
          my_function