[Reg 6.5 -> 6.6] Calling QPromise::finish() from the same thread deadlocks i

#include <QCoreApplication>
#include <QFuture>
#include <QTimer>

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);

    QPromise<QString> promise;
    promise.start();

    // Wait 1 second and then complete the task
    QTimer::singleShot(1000, &app, [&] {
        promise.addResult("Task is complete");
        qDebug("Finishing...");
        promise.finish();
        qDebug("...finished!");
    });

    promise.future().then(&app, [](const QString& result) {
        qDebug() << "Future lambda:" << result;
        qApp->quit();
    });

    return app.exec();
}