Re: Changes in C++ FE regarding pedwarns to be errors are harmful

["Ismail Dönmez" <ismail@pardus.org.tr>]

Hi Manuel,

Wednesday 09 January 2008 00:28:54 tarihinde Manuel López-Ibáñez şunları 
yazmıştı:
> I implemented the change as the fix to a bug that was reported by
> fellow (and more senior) GCC developers. Let me try to explain
> (although, I hoped that it will be fairly clear from
> gcc.gnu.org/gcc-4.3/changes.html).

Yeah I know this change is documented at least.

> We have a series of diagnostics that are important or required by the
> standard (or both). Those are called pedwarns. It is an unfortunate
> name for two reasons: 1) Not all pedwarns are enabled by -pedantic,
> some are enabled by default; and 2) pedwarns can be either warnings or
> errors, and what they are depends on command-line options and the
> default of each front-end.  In fact, pedwarnss are warnings by default
> in the C front-end. But they are errors by default in the C++
> front-end unless you use -fpermissive so they are downgraded to
> warnings.
>
> Before GCC 4.3, the C++ preprocessor was ignoring the default of the
> C++ front-end. In fact, there was an inconsistence between the
> settings of the C++ preprocessor and the settings of the C++
> front-end. It worked for a few things (-pedantic-errors worked fine),
> but not for others (the default settings and the effect of
> -fpermissive). The inconsistency was evident in the code and if you
> played with combinations of -pedantic-errors and -fpermissive.

Oh that clears up my confusion. So the right fix would be downgrading this 
redefinition problem to be pedwarn instead. But I see no point in creating a 
bug report if its just gonna be closed as invalid, so I hope we can discuss 
if its feasible to downgrade this error to be a pedwarn.

What I see right now this distributions plug -fpermissive in and just go away. 
But I don't like workarounding gcc this way. I hope we can all agree that 
downrading this error to be a pedwarn is the correct way to go.

Regards,
ismail

-- 
Never learn by your mistakes, if you do you may never dare to try again.