Creating button when QDialog is being destructed

Q_Q(QMessageBox);
    if (q->testAttribute(Qt::WA_WState_ExplicitShowHide) && q->testAttribute(Qt::WA_WState_Hidden) != visible)
        return;

    // Last minute setup
    if (autoAddOkButton)
        q->addButton(QMessageBox::Ok);
    detectEscapeButton();

    if (canBeNativeDialog())
        setNativeDialogVisible(visible);

    // Update WA_DontShowOnScreen based on whether the native dialog was shown,
    // so that QDialog::setVisible(visible) below updates the QWidget state correctly,
    // but skips showing the non-native version.
    q->setAttribute(Qt::WA_DontShowOnScreen, nativeDialogInUse);