named warnings & individual warning control

[Geert Bosch]

On Jun 22, 2004, at 13:36, Mark Mitchell wrote:
>> By definition, ALL messages would have a user-visible mnemonic,
>> however ugly.
> This is the kind of thing I think is important to decide.
>
> The problem, in my mind, is that as soon as you provide the mnemonic, 
> people will want and expect it to be stable, no matter what else you 
> tell them.  From a technical point of view, you can say "well, I never 
> promised them that".  But, from a marketing/support point of view, 
> you've now got a whole new can of worms.  The current system, at 
> least, does not make any false promises.

This is indeed a huge problem, since these mnemonics end up all over the
source and will cause maintenance problems, both for GCC and for user 
code.

In GNAT, we use a pragma Warnings (Off|On) or  pragma Warnings (Off,
some_entity). In essence this allows suppressing all warnings in very
specific places, instead of adding fine grained warning control that
remains in effect throughout the compilation unit. Warnings change quite
often and are split or merged at times, so it will be hard to keep
mnemonics stable enough to not require source changes.

   -Geert