Re: C++ error

[Laurent Gatto <laurent.gatto@gmail.com>]

Thank you for your help, Fredrik.

Bug filed here: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=74455

Laurent

On Mon, 18 Nov 2024 at 19:49, Fredrik Salomonsson <plattfot@posteo.net> wrote:
>
> Hi,
>
> Laurent Gatto <laurent.gatto@gmail.com> writes:
>
> > On Sat, 16 Nov 2024 at 11:56, Laurent Gatto <laurent.gatto@gmail.com> wrote:
> >>
> >> Hi Fredrik,
> >>
> >> Excellent advice, and I was able to identify the culprit.
>
> Awesome!
>
> >> Here's a simple reproducible example
> >>
> >> $ guix shell --container gcc-toolchain
> >> [env]$ g++ main.cpp
> >> [env]$ exit
> >>
> >> $ guix shell --container gcc-toolchain gfortran-toolchain
> >> [env]$ g++ main.cpp
> >> In file included from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/bits/move.h:57,
> >>                  from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/bits/exception_ptr.h:43,
> >>                  from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/exception:153,
> >>                  from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/ios:39,
> >>                  from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/ostream:38,
> >>                  from
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/iostream:39,
> >>                  from main.cpp:1:
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/type_traits:732:26:
> >> error: expected identifier before '(' token
> >>   732 |     _GLIBCXX20_DEPRECATED("use is_standard_layout &&
> >> is_trivial instead")
> >>       |                          ^
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/type_traits:732:27:
> >> error: expected unqualified-id before string constant
> >>   732 |     _GLIBCXX20_DEPRECATED("use is_standard_layout &&
> >> is_trivial instead")
> >>       |                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/type_traits:732:27:
> >> error: expected ')' before string constant
> >>   732 |     _GLIBCXX20_DEPRECATED("use is_standard_layout &&
> >> is_trivial instead")
> >>       |                          ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>       |                           )
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/type_traits:3154:25:
> >> error: expected unqualified-id before string constant
> >>  3154 |   _GLIBCXX20_DEPRECATED("use is_standard_layout_v &&
> >> is_trivial_v instead")
> >>       |
> >> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> /gnu/store/68l504nyvms77jzfg9yf4njiyfbi8gm2-profile/include/c++/type_traits:3154:25:
> >> error: expected ')' before string constant
> >>  3154 |   _GLIBCXX20_DEPRECATED("use is_standard_layout_v &&
> >> is_trivial_v instead")
> >>       |
> >> ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>       |                         )
> >
> > The order of the packages does matter. The above fails, but if I pass
> > gfortran-toolchain before gcc-toolchain, it works:
> >
> > $ guix shell --container gfortran-toolchain gcc-toolchain
> > [env]$ g++ main.cpp
> > [env]$ ./a.out
> > 201703
> >
> > Is this really expected?
>
> This sounds like a bug.  Especially if it is order dependent if it works
> or not.  And I can confirm that I can reproduce it on my end as well.
>
> >> I also confirmed that I was able to compile that source code by simply
> >> commenting gfortran-toolchain in my system manifest.
> >>
> >> Isn't this weird though? What if I need both?
>
> It should work to have both in the same context.  Probably some issue
> with how they are package up — I haven't checked the packaging for them.
> But I have built gcc from source with both g++ and gfortran without any
> issues.  That was gcc-9 and gcc-11 so maybe something broke in upstream
> with gcc-14?  Although I find that unlikely.
>
> Anyway, best is to send in a bug report to guix now that you have a
> small reproducible test that show case the issue.
>
> --
> s/Fred[re]+i[ck]+/Fredrik/g