uic uses new signal/slots syntax but does not use qOverload template. For example, uic produces uncompilable code for forms with connection to QLabel::setNum(int) slot. See attached example.

Compilation error:

In file included from mainwindow.cpp:4:0:

ui_mainwindow.h: In member function ‘void Ui_MainWindow::setupUi(QMainWindow*)’:

ui_mainwindow.h:71:90: error: no matching function for call to ‘QObject::connect(QSlider*&, void (QAbstractSlider::)(int), QLabel&, <unresolved overloaded function type>)’

QObject::connect(horizontalSlider, &QSlider::valueChanged, label, &QLabel::setNum);

^