#include <iostream>
#include <functional>
using namespace std;
class Dispatcher
{
private:
    std::function<void()> callback_;
public:
    void addRequest(std::function<void()> callback)
    {
        callback_ = callback;
    }
    void start()
    {
        callback_();
    }
};

class Worker
{
public:
    void start(Dispatcher* dispatcher)
    {
        dispatcher->addRequest([=](){notifier();});
    }
private:
    void notifier()
    {
        bDone = true;
    }
    bool bDone{false};
};

int main()
{
    Dispatcher* dispatcher = new Dispatcher();
    Worker* worker = new Worker();
    worker->start(dispatcher);
    delete worker;//open this line to get a crash
    dispatcher->start();
    return 0;
}

如上代码所示：

1. 虽然这行代码：dispatcher->addRequest([=](){notifier();});中使用了[=]这样的隐式值捕获，但是notifier这里其实还是引用到了this->notifier这样的。所以是隐式的引用到了this指针。
2. delete worker以后this指针失效。
3. dispatcher回调worker以后，走到worker的notifer中，操作成员数据bDone。
4. 因为worker已经析构，crash。