QObject: Fixed QObject::connect connection type has different behaviors

[suchone]

QObject: Fixed QObject::connect connection type has different behaviors when using Qt::AutoConnection and Qt::QueuedConnection in cross-thread

For example:

class MyThread : public QThread
{
Q_OBJECT
public:
void run() override
{
QMap<int, int> result;

	//do something, then emit signal after task finished
	emit taskFinished(result);
}

signals:
void taskFinished(const QMap<int, int>& result);
};

class MyWidget : public QWidget
{
Q_OBJECT
public:
MyWidget()
{
MyThread* myThread = new MyThread();

	//If connection type is Qt::QueuedConnection, the taskFinished(result) signal can be triggered normally and the slot can be executed normally
	QObject::connect(myThread, &MyThread::taskFinished, this, &MyWidget::onTaskFinished, Qt::QueuedConnection);

	//If not set connection type (Qt::AutoConnection as default), when thread emit taskFinished(result) it will output error
	//QObject::connect: Cannot queue arguments of type 'QMap<int,int>'
	//(Make sure 'QMap<int,int>' is registered using qRegisterMetaType().)
	QObject::connect(myThread, &MyThread::taskFinished, this, &MyWidget::onTaskFinished);

	myThread->start();
}

public slots:
void onTaskFinished(const QMap<int, int>& result)
{
//do something
}
};

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