Re: c++/8931: g++ 3.2 fails to enforce access rules

["Martin v. Löwis" <martin at v dot loewis dot de>]

[8931]
> g++ 3.2 fails to enforce access rules

[Wolfgang]
> Since it is not a regression, it is not going to be fixed
> in any 3.2.* 

[Gaby]
> It would be really helpful if non-invasive bug fixes could make it to
> branch when it is not frozen.

While I sympathize with this request, I think clear policies are
needed; and "it is non-invasive" is not clear enough.

Instead, I would propose a policy under which this specific fix would
not be backported, as it is from the "accepts-illegal" class. People
running into this bug can use all well-formed code with a compiler
that only has accepts-illegal bugs, so having such bugs in a
maintenance release should be no obstacle for any user. At worst,
users will find that other compilers reject the code, at which point
they will have to fix their code, and be done with it.

More specifically:
- do backport:
  class is rejects-legal, wrong-code, ice-on-legal-code

- don't backport:
  class is accepts-illegal, ice-on-illegal-code, change-request, support
  severity is serious or non-critical (i.e. a work-around is possible)

I realise that this classification is both overlapping and
non-exhausting. If in doubt, don't backport.

As for rejecting backports because of severity: it would be good to
collect the possible work-arounds in case the work-around isn't
obvious (or it isn't obvious what the problem is), and the bug is
frequently reported.

Just my 0.02EUR,

Martin