Using custom C++ enum flags in QML is not documented well enough

http://doc.qt.io/qt-5/qtqml-cppintegration-data.html

Suppose you had a property that you wanted to be a combination of enum flags:

Q_PROPERTY(ClosePolicy closePolicy READ closePolicy WRITE setClosePolicy NOTIFY closePolicyChanged FINAL)

You would declare the enum like so, using Q_DECLARE_FLAGS and Q_FLAG:

    enum ClosePolicyType {
        DontCloseOnEvents = 0x0,
        CloseOnPress = 0x1,
        CloseOnRelease = 0x2,
        CloseOnEscape = 0x4
    };
    Q_DECLARE_FLAGS(ClosePolicy, ClosePolicyType)
    Q_FLAG(ClosePolicy)

You'd then register the containing type:

qmlRegisterType<QQuickPopup>(uri, 1, 0, "Popup");

And try to use it:

Popup {
    closePolicy: Popup.DontCloseOnEvents
}

You'll get an error. Something like "cannot assign int to unknown property type".

You have to use QML_DECLARE_TYPE:

QML_DECLARE_TYPE(QQuickPopup)

I would suggest adding a line to http://doc.qt.io/qt-5/qqmlengine.html#QML_DECLARE_TYPE that says something like:

This macro must be used for types that declare enum flags that are to be used from QML.

Also, http://doc.qt.io/qt-5/qtqml-cppintegration-data.html#enumeration-types should mention (maybe in a "Flags" sub header) how to properly declare enum flags in C++ in order to use them in this manner in QML.