There is a typo within the usage example of Q_FLAG

https://doc.qt.io/qt-5/qobject.html#Q_FLAG

I believe it should be
Q_FLAG(LoadHints)
instead of
Q_FLAG(LoadHint)
At least this fixed my usage issues of Q_FLAG:

moc_uLog.cpp:214:67: error: conversion from ‘QFlag’ to ‘ULog::ULogLevel’ is ambiguous

214 | case 1: _t->setLogLevel(QFlag(reinterpret_cast<int>(_v))); break;

       |                                                                                                    ^