Crash on QWindowPrivate::updateDevicePixelRatio() with nullptr access

Unhandled exception thrown: read access violation.
**this** was nullptr.

>	Qt6Gui.dll!QScreen::devicePixelRatio() Line 287	C++
 	Qt6Gui.dll!QWindowPrivate::updateDevicePixelRatio() Line 1410	C++
 	[Inline Frame] Qt6Core.dll!QtPrivate::QSlotObjectBase::call(QObject *) Line 469	C++
 	Qt6Core.dll!doActivate<0>(QObject * sender, int signal_index, void * * argv) Line 4086	C++
 	Qt6Core.dll!QMetaObject::activate(QObject * sender, const QMetaObject * m, int local_signal_index, void * * argv) Line 4147	C++
 	[Inline Frame] Qt6Gui.dll!QWindow::screenChanged(QScreen * _t1) Line 817	C++
 	[Inline Frame] Qt6Gui.dll!QWindowPrivate::emitScreenChangedRecursion(QScreen *) Line 496	C++
 	Qt6Gui.dll!QWindowPrivate::setTopLevelScreen(QScreen * newScreen, bool recreate) Line 520	C++
 	Qt6Gui.dll!QWindowSystemInterface::handleScreenRemoved(QPlatformScreen * platformScreen) Line 765	C++
 	qwindows.dll!QWindowsScreenManager::handleScreenChanges() Line 812	C++
 	qwindows.dll!qDisplayChangeObserverWndProc(HWND__ * hwnd, unsigned int message, unsigned __int64 wParam, __int64 lParam) Line 676	C++
 	[External Code]	
 	Qt6Core.dll!QEventDispatcherWin32::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 487	C++
 	Qt6Gui.dll!QWindowsGuiEventDispatcher::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 37	C++
 	[Inline Frame] Qt6Core.dll!QEventLoop::processEvents(QFlags<enum QEventLoop::ProcessEventsFlag>) Line 100	C++
 	Qt6Core.dll!QEventLoop::exec(QFlags<enum QEventLoop::ProcessEventsFlag> flags) Line 181	C++
 	Qt6Core.dll!QCoreApplication::exec() Line 1486	C++

bool QWindowPrivate::updateDevicePixelRatio()
{
    Q_Q(QWindow);

    // If there is no platform window use the associated screen's devicePixelRatio,
    // which typically is the primary screen and will be correct for single-display
    // systems (a very common case).
    const qreal newDevicePixelRatio = platformWindow ?
        platformWindow->devicePixelRatio() * QHighDpiScaling::factor(q) : q->screen()->devicePixelRatio();
...