[PATCH] PR18327: -Wsystem-headers introduces build errors

[Marshall Clow]

On Jan 9, 2014, at 2:20 PM, Richard Smith <richard at metafoo.co.uk> wrote:

> On Thu, Jan 9, 2014 at 7:25 AM, Alp Toker <alp at nuanti.com> wrote:
>  
> It's not fair on the user or the system header maintainers to bring up unexpected errors with this flag.
> 
> I don't think this is clear. If the code in the system header is ill-formed, I would expect the system header maintainers to be *grateful* that we flag it as an error and not just as a warning. But I'll wait to hear what they have to say about that.

A few points, in no particular order:

* If we have ill-formed code in system headers, I would expect it to fail to compile whether the user specifies -Wsystem-headers or not.

* If a user has a clean build, and then rebuilds with -Wsystem-headers, I would expect to get warnings - not errors. [ Isn’t that what PR18327 is all about? ]

* There are some “interesting” language features which are only enabled for system headers, and cause warnings if used in user code.
[ User-defined suffixes that do not start with an underscore, for example. ]

— Marshall
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