https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121244
Franz Sirl <sirl at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |sirl at gcc dot gnu.org --- Comment #3 from Franz Sirl <sirl at gcc dot gnu.org> --- Created attachment 61982 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=61982&action=edit -save-temps result With Qt6 (6.6.2 here) headers it happens with a simple #include <Qt6Core/qstring.h> compiled with # g++-trunk -std=gnu++20 -c -Wsfinae-incomplete -I /usr/include/qt6 test-qt6.cpp In file included from /usr/include/qt6/QtCore/qstring.h:22, from test-qt6.cpp:2: /usr/include/qt6/QtCore/qanystringview.h:31:7: warning: defining 'QAnyStringView', which previously failed to be complete in a SFINAE context [-Wsfinae-incomplete=] 31 | class QAnyStringView | ^~~~~~~~~~~~~~ In file included from /home/fsirl/rpmbuild/BUILD/gcc-16.0.0+gitr16+2484/libstdc++-v3/include/std/unordered_map:44, from /home/fsirl/rpmbuild/BUILD/gcc-16.0.0+gitr16+2484/libstdc++-v3/include/std/functional:80, from /usr/include/qt6/QtCore/qchar.h:9, from /usr/include/qt6/QtCore/qstring.h:14: /home/fsirl/rpmbuild/BUILD/gcc-16.0.0+gitr16+2484/libstdc++-v3/include/bits/range_access.h:325:24: note: here. Use '-Wsfinae-incomplete=2' for a diagnostic at that point 325 | -> decltype(__cont.data()) | ~~~~~~~^~~~ I'm attaching the compressed -save-temps output.