[cfe-dev] Overeager -Wswitch

[Yury Gribov via cfe-dev]

On 10/11/2015 09:59 PM, Joerg Sonnenberger via cfe-dev wrote:
> On Sun, Oct 11, 2015 at 07:58:32PM +0200, Kim Gräsman wrote:
>> Hi Joerg,
>>
>> On Sat, Oct 10, 2015 at 1:33 PM, Joerg Sonnenberger via cfe-dev
>> <cfe-dev at lists.llvm.org> wrote:
>>> On Sat, Oct 10, 2015 at 10:21:17AM +0200, Kim Gräsman via cfe-dev wrote:
>>>> Alternatively, if we could get a patch into Poco, is there something
>>>> like MSVC's #pragma(warning:disable) for Clang, so they could
>>>> selectively silence the warning around this function?
>>>
>>> add GCC diagnostic push
>>> #pragma GCC diagnostic ignored "-Wswitch"
>>> ... your function here...
>>> #pragma GCC diagnostic pop
>>>
>>> I think it also works with clang as pragma group.
>>
>> Thanks, that's what I was looking for in the way of disabling. To
>> confirm, #pragma clang diagnostic also works.
>>
>> I think we've agreed to rewrite the function in Poco using if/else
>> instead of switch, because it was hard to find a switch phrasing that
>> worked with all -W combinations (-Weverything overrode the #pragma
>> diagnostic and threw diagnostics for code that worked with -Wall).
>>
>> That said, it might be worth trying to make Clang aware of libstdc++'s
>> enum convention, but I haven't thought of a way to do so yet.
>
> I don't think there is anything Clang can or should do here, but please
> fill an upstream report against GCC if they still do it in the most
> recent version.

Using the last enum value (often suffixed with "_end" or "_last") to 
track total number of values is a common coding practice so I'm not sure 
they are going to fix this.

-Y