Re: type based aliasing again

[Richard Stallman <rms@gnu.org>]

    However, I have a rather serious objection: it means that users cannot
    tell whether their code is valid, even according to the GCC rules,
    without knowing the internals of the compiler.

This has always been true.  It is true in the current version of GCC
with regard to aliasing, even when -fstrict-aliasing is used.  It is
part of the nature of C.

The goal of trying to avoid it is unrealistic and misguided; it can't
be done.  So this cannot be a valid reason to reject a change.

    The compiler should continue to aggressively break code that
    misbehaves in this way.

This proposes to break users' code, just to bully them into changing
it.  That is a callous and harsh attitude towards the users of GCC.
No wonder users are angry.  They know that the problems are not due to
necessity, but due to callous disregard for them.

We cannot do everything all users want, and sometimes a maintainer has
to say no to users.  "You cannot please everyone," as the saying goes.
There are many kinds of reasons which can sometimes be good reasons to
say no.

But maintainers should always say no reluctantly--never eagerly.  We
should never aggressively cause trouble for users today, just because
someday it might be necessary.  That is like amputating limbs because
someday they might be crushed.

This treatment of users brings shame on the GNU Project.  I ask
everyone therefore not to suggest that we should treat users this way.