On Tue, Apr 25, 2017 at 11:42 AM, Nico Weber <tha...@chromium.org> wrote:
> On Tue, Apr 25, 2017 at 2:06 PM, David Majnemer <david.majne...@gmail.com> > wrote: > >> >> >> On Tue, Apr 25, 2017 at 8:46 AM, Nico Weber <tha...@chromium.org> wrote: >> >>> On Mon, Apr 24, 2017 at 10:00 PM, David Majnemer < >>> david.majne...@gmail.com> wrote: >>> >>>> >>>> >>>> On Mon, Apr 24, 2017 at 11:56 AM, Nico Weber <tha...@chromium.org> >>>> wrote: >>>> >>>>> "Opting into the conforming mode, /permissive-, during the series of >>>>> VS 2017 update is a commitment to keeping your code base clean and to >>>>> fixing non-conforming constructs we fix conformance issues in Visual C++." >>>>> [...] "By contrast /permissive- offers a useful conformance mode where >>>>> input C++ code is interpreted according to ISO C++ rules but also allows >>>>> conforming extensions necessary to compile C++ on targets supported by >>>>> Visual C++." >>>>> >>>>> I guess the second quote agrees with your interpretation. >>>>> >>>>> We already diag most of the things they already mention. The one thing >>>>> we don't diag by default is Wmicrosoft-enum-forward-reference since >>>>> that's only an Extension and not an ExtWarn. We don't expose -pedantic >>>>> from >>>>> clang-cl, so this seemed like a somewhat natural mapping to me. >>>>> >>>>> Should /permissive- map to -Wmicrosoft instead and turn on the parts >>>>> of -Wmicrosoft that are Extensions? >>>>> >>>> >>>> Did you mean on or off? >>>> >>> >>> On. >>> >>> >>>> I think that their intent is that things like __declspec remain OK. >>>> >>> >>> Nothing in -Wmicrosoft warns on __declspec. >>> >>> >>>> They want to diagnose non-conforming extensions like crazy template >>>> stuff, bogus typedef syntax, bad main function definitions, etc. >>>> >>> >>> Right. The only thing it currently makes cl warn on that clang-cl >>> doesn't warn on by default is Wmicrosoft-enum-forward-reference, which >>> is an Extension warning, not an ExtWarn. So mapping /permissive- to >>> -Wmicrosoft would make clang-cl diagnose forward-declared enums like it >>> does with 2017 cl. >>> >> >> Ok, sounds like it diagnoses the same sorts of things. They diagnose as >> error though, I think we should too. What about -fdelayed-template-parsing? >> Shouldn't that be disabled? >> > > CL has added a /Zc:twoPhase for that (not yet released anywhere), and Hans > added support for that to clang-cl a while ago. Some blog post (maybe the > one I linked to?) says that they're thinking of possibly > enabling /Zc:twoPhase when /permissive- is passed, but at the moment it's > independent. (In part because /permissive- ships in VC2017 and /Zc:twoPhase > hasn't been shipped yet). > Ok. > > What's the advantage of making it an error? > All the diagnostics they show in https://blogs.msdn.microsoft.com/vcblog/2016/11/16/permissive-switch/ diagnose as errors. > If it's a warning, you can pass -Werror separately if you want. And > SFINAE'ing on this seems like asking for trouble. > I said nothing about permitting SFINAE on these errors. > > >> >> >>> >>> >>>> >>>> >>>>> Should we just ignore /permissive- and possibly make some of our >>>>> -Wmicrosoft Extensions ExtWarns instead? >>>>> >>>>> On Mon, Apr 24, 2017 at 2:10 PM, David Majnemer < >>>>> david.majne...@gmail.com> wrote: >>>>> >>>>>> -pedantic means "Issue all the warnings demanded by strict ISO C and >>>>>> ISO C++; reject all programs that use forbidden extensions, and some >>>>>> other >>>>>> programs that do not follow ISO C and ISO C++." >>>>>> I believe it is more akin to -fno-ms-compatibility as it disables >>>>>> compatibility hacks. >>>>>> >>>>>> On Mon, Apr 24, 2017 at 11:02 AM, Nico Weber <tha...@chromium.org> >>>>>> wrote: >>>>>> >>>>>>> It does sound pretty similar to me from the blog post. I think this >>>>>>> is a decent place to start from. >>>>>>> >>>>>>> On Apr 24, 2017 11:55 AM, "David Majnemer via Phabricator via >>>>>>> cfe-commits" <cfe-commits@lists.llvm.org> wrote: >>>>>>> >>>>>>>> majnemer requested changes to this revision. >>>>>>>> majnemer added a comment. >>>>>>>> This revision now requires changes to proceed. >>>>>>>> >>>>>>>> I don't think this is correct. GDR (of Microsoft) says the behavior >>>>>>>> is different: https://www.reddit.com/r/cpp/comm >>>>>>>> <https://www.reddit.com/r/cpp/comments/5dh7j5/visual_c_introduces_permissive_for_conformance/da5fxjj/> >>>>>>>> LOG(INFO) << "n_window_index: " << n_window_index; >>>>>>>> ents/5dh7j5/visual_c_introduces_permissive_for_conformance/da5fxjj/ >>>>>>>> <https://www.reddit.com/r/cpp/comments/5dh7j5/visual_c_introduces_permissive_for_conformance/da5fxjj/> >>>>>>>> >>>>>>>> >>>>>>>> https://reviews.llvm.org/D32435 >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> cfe-commits mailing list >>>>>>>> cfe-commits@lists.llvm.org >>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
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