插槽参数（有时）无效

Question

在10-20个信号调用之一中，我在插槽中有一个无效参数。问题归结为以下

class Sender : public QEnabledSharedFromThis<Sender>
{
public:
    void emitSignal() 
    {
        emit someSignal(sharedFromThis())
    }

signals:
    someSignal(const QSharedPointer<Sender>&);

    int m_i;
};

qRegisterMetaType<QSharedPointer<Sender>>();

Sender sender;

class Receiver
{
    Receiver()
    {
        connect(&sender, &Sender::emitSignal, this, [this](const QSharedPointer<Sender>& sender) {
            // Crash here.
            // 'sender' argument seems invalid (dangling reference)
            qDebug() << sender->m_i;
        })  
    }
};

当发生这种情况时，我可以在QCoreApplication::notifyInternal2（例如）中的崩溃转储中看到：

event->nargs == 2 // ok
event->type[0] == 0 // ok
event->type[1] == some reasonable value like 1105
event->sender is alive and seems correctly initialized

但event->args似乎无效。

event->args[0] != 0
(Sender*)(args[1]) is full of  'can't read memory'

平台是Win64，qt版本是5.6.1，编译器是vs2015。发布。 有什么想法吗？感谢。