...which was introduced in
<https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=117782e0c2a81a4b8170f87f0fe7190ee22548e2>
"c++: add -Wsfinae-incomplete" and causes warnings like
> In file included from include/vcl/event.hxx:28,
> from libreofficekit/source/gtk/lokdocview.cxx:26:
> include/vcl/outdev.hxx:160:37: error: defining ‘OutputDevice’, which previously failed to be complete in a SFINAE context [-Werror=sfinae-incomplete=]
> 160 | class SAL_WARN_UNUSED VCL_DLLPUBLIC OutputDevice : public virtual VclReferenceBase
> | ^~~~~~~~~~~~
> In file included from include/vcl/vclevent.hxx:24,
> from include/svtools/colorcfg.hxx:29,
> from include/vcl/themecolors.hxx:12,
> from include/vcl/settings.hxx:26,
> from include/vcl/event.hxx:26:
> include/vcl/vclptr.hxx:44:13: note: here. Use ‘-Wsfinae-incomplete=2’ for a diagnostic at that point
> 44 | int (*)[sizeof(T)])
> | ^~~~~~~~~
because
> include/vcl/vclptr.hxx:44:13: error: failed to complete ‘OutputDevice’ in SFINAE context [-Werror=sfinae-incomplete=]
> 44 | int (*)[sizeof(T)])
> | ^~~~~~~~~
> include/vcl/vclptr.hxx: In substitution of ‘template<class T> constexpr bool vcl::detail::isIncompleteOrDerivedFromVclReferenceBase(int (*)[sizeof (T)]) [with T = VirtualDevice]’:
> include/vcl/vclptr.hxx:60:79: required from ‘class VclPtr<VirtualDevice>’
> 60 | vcl::detail::isIncompleteOrDerivedFromVclReferenceBase<reference_type>(
> | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
> 61 | nullptr),
> | ~~~~~~~~
> include/vcl/outdev.hxx:188:37: required from here
> 188 | VclPtr<VirtualDevice> mpAlphaVDev;
> | ^~~~~~~~~~~
As discussed in the newly added comment in include/vcl/vclptr.hxx, until we can
address this with C++26 reflection, "use a HACK of (globally) ignoring that
warning". (Which required adding a new HAVE_GCC_WSFINAE_INCOMPLETE configure
check.)
Change-Id: Ie1b44e730cf6b6269572158f6bd50e8911c15846
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/188115
Reviewed-by: Stephan Bergmann <stephan.bergmann@collabora.com>
Tested-by: Jenkins
Stephan Bergmann
dc01bb6306