[cfe-dev] should -Wimplicit-fallthrough require C++11?

Douglas Gregor dgregor at apple.com
Mon Nov 12 06:35:35 PST 2012

On Nov 10, 2012, at 10:41 AM, Nico Weber <thakis at chromium.org> wrote:

> On Fri, Nov 9, 2012 at 8:15 PM, Ted Kremenek <kremenek at apple.com> wrote:
>> On Nov 9, 2012, at 7:04 PM, Richard Smith <richard at metafoo.co.uk> wrote:
>> The original intention was that the warning could be used in any
>> language mode, if you wanted a warning on *all* switch fallthrough,
>> and that people who didn't want that could just not turn it on.
>> Right.
>> I
>> guess the complaints you're receiving are for situations where the
>> warning can't simply be disabled (or not enabled in the first place)?
>> What has happened is that a fair number of users have discovered this
>> warning using -Weverything.  When they first discover it they find it
>> interesting.  After they discover that they cannot add an annotation (as the
>> warning suggests) they get very frustrated.  They are then left with the
>> choice of just turning the warning off, or using pragmas.  For those users
>> who like the warning in principle, but find that they cannot use it in
>> practice because of these limitations (because they are not using C++11)
>> they view it is an incomplete feature.  Several people have thus requested
>> to not see the warning at all.
> If you're using -Weverything, shouldn't the expectation be that you'll
> end up turning off several warnings?

Yes, but only if those warnings aren't useful to your situation. This warning should have widespread applicability, but it's actually useless outside of C++11 because there's no clean workaround.

	- Doug

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