[Interest] [Qt6] QML_ATTACHED failing with ::QQmlPrivate not declared

[Ulf Hermann]

> I didn't mean the name's wrong, simply that I read 
> <QQml/qqmlregistration.h> in the docs instead of <QQmlRegistration> or 
> something akin.

<QQmlRegistration> would import a class called "QQmlRegistration". There 
is no such class in that header. It's a collection of macros. The 
correct form is <QtQml/qqmlregistration.h>.

best regards,
Ulf