[ChangeLog][QtCore][Global] Added the QT_NO_FLOAT16_OPERATORS macro in
order to work around a Microsoft <= VS2017 compiler bug that is
exposed when using std::bitset along with any Qt header that includes
<qfloat16.h>.
This is fixed in MSVC 2019[1], but the workaround is needed for
earlier versions.
In this case, cl.exe fails with
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.10.25017\include\bitset(270): error C2666: 'operator /': 10 overloads have similar conversions
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qsize.h(364): note: could be 'const QSizeF operator /(const QSizeF &,qreal)'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qsize.h(194): note: or 'const QSize operator /(const QSize &,qreal)'
c:\qt\5.12.0\msvc2017_64\include\qtcore\qmargins.h(427): note: or 'QMarginsF operator /(const QMarginsF &,qreal)'
c:\qt\5.12.0\msvc2017_64\include\qtcore\qmargins.h(213): note: or 'QMargins operator /(const QMargins &,qreal)'
c:\qt\5.12.0\msvc2017_64\include\qtcore\qmargins.h(207): note: or 'QMargins operator /(const QMargins &,int)'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(205): note: or 'double operator /(int,qfloat16) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(205): note: or 'double operator /(qfloat16,int) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(195): note: or 'float operator /(float,qfloat16) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(195): note: or 'float operator /(qfloat16,float) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(194): note: or 'double operator /(double,qfloat16) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(194): note: or 'double operator /(qfloat16,double) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(193): note: or 'long double operator /(long double,qfloat16) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(193): note: or 'long double operator /(qfloat16,long double) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qfloat16.h(176): note: or 'qfloat16 operator /(qfloat16,qfloat16) noexcept'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qpoint.h(402): note: or 'const QPointF operator /(const QPointF &,qreal)'
C:\Qt\5.12.0\msvc2017_64\include\QtCore/qpoint.h(206): note: or 'const QPoint operator /(const QPoint &,qreal)'
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.10.25017\include\bitset(270): note: or 'built-in C++ operator/(::size_t, )'
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.10.25017\include\bitset(270): note: while trying to match the argument list '(::size_t, )'
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.10.25017\include\bitset(266): note: while compiling class template member function 'std::bitset<8> &std::bitset<8>::set(::size_t,bool)'
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\VC\Tools\MSVC\14.10.25017\include\bitset(39): note: see reference to function template instantiation 'std::bitset<8> &std::bitset<8>::set(::size_t,bool)' being compiled
..\Qt5.12.0-C2666\main.cpp(7): note: see reference to class template instantiation 'std::bitset<8>' being compiled
Invoke this workaround by defining the macro QT_NO_FLOAT16_OPERATORS
in user code prior to the inclusion of Qt includes in a translation
unit.
Arithmetic operators from qfloat16 will then not be present in that
compilation unit.
[1] https://developercommunity.visualstudio.com/content/problem/406329/compiler-error-c2666-when-using-stdbitset-and-cust.html
Task-number: QTBUG-72073
Change-Id: I58f8400bf933ad781d4213731695e20e0c482166
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
b7edc811ec