QFileInfo in Qt6.3 MinGW broken?

[VRonin]

Hi, I'm having a problem when including QFileInfo in my project using Qt 6.3 on MinGW on my CI

[ 15%] Building CXX object examples/exam_ModelSerialisation/CMakeFiles/exam_ModelSerialisation.dir/exam_modelserialisation.cpp.obj
In file included from C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/filesystem:37,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtCore/qfile.h:49,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtCore/qfileinfo.h:43,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtCore/QFileInfo:1,
                 from D:\a\QtModelUtilities\QtModelUtilities\examples\exam_ModelSerialisation\exam_modelserialisation.cpp:10:
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/fs_path.h: In member function 'std::filesystem::__cxx11::path& std::filesystem::__cxx11::path::operator/=(const std::filesystem::__cxx11::path&)':
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/fs_path.h:237:47: error: no match for 'operator!=' (operand types are 'std::filesystem::__cxx11::path' and 'std::filesystem::__cxx11::path')
    || (__p.has_root_name() && __p.root_name() != root_name()))
                               ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
In file included from C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/utility:70,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtCore/qglobal.h:47,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtGui/qtguiglobal.h:43,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtWidgets/qtwidgetsglobal.h:43,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtWidgets/qapplication.h:43,
                 from D:/a/QtModelUtilities/Qt/6.3.0/mingw_64/include/QtWidgets/QApplication:1,
                 from D:\a\QtModelUtilities\QtModelUtilities\examples\exam_ModelSerialisation\exam_modelserialisation.cpp:1:
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/stl_pair.h:456:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator!=(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)'
     operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
     ^~~~~~~~
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/stl_pair.h:456:5: note:   template argument deduction/substitution failed

(full output available here: https://github.com/VSRonin/QtModelUtilities/runs/6321094127?check_suite_focus=true)
exam_modelserialisation.cpp:10 is a line with #include <QFileInfo>

All other platforms/versions work so wanted to know if it's a problem with my CI or with the MinGW version of Qt 6.3

[cristian-adam]

MinGW 8.1 is a bit dated. See https://wiki.qt.io/MinGW for which version of MinGW Qt has been built with.

Please upgrade your MinGW version on your CI.

[manordheim]

C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/include/c++/bits/fs_path.h:237:47: error: no match for 'operator!=' (operand types are 'std::filesystem::__cxx11::path' and 'std::filesystem::__cxx11::path')
    || (__p.has_root_name() && __p.root_name() != root_name()))`

The real problem is here. It cannot find an operator!= for std::filesystem::path.

For some reason it has __cxx11 in the path? I'm not sure what that but if it's related to c++ std version used then you need to update it, Qt 6 requires C++17.

[cristian-adam]

MinGW 8.1 is a bit dated. See https://wiki.qt.io/MinGW for which version of MinGW Qt has been built with.

Please upgrade your MinGW version on your CI.

[VRonin]

I knew it was something silly, thanks!