如何将pimpl-idiom实例从子实例传递到父实例？

// Parent.h
#ifndef PARENT_H
#define PARENT_H

#include <memory>

class Parent {
public:
    virtual ~Parent();
    virtual void doSomething() = 0;

protected:
    Parent();

private:
    class Impl;
    std::unique_ptr<Impl> pImpl;
};

#endif // PARENT_H

// Child.h
#ifndef CHILD_H
#define CHILD_H

#include "Parent.h"

class Child : public Parent {
public:
    Child();
    ~Child();
    void doSomething() override;

private:
    class Impl;
    std::unique_ptr<Impl> pImpl;
};

#endif // CHILD_H

// Parent.cpp
#include "Parent.h"
#include <iostream>

class Parent::Impl {
public:
    virtual ~Impl() = default;
    virtual void doSomething() = 0;
};

Parent::Parent() : pImpl(nullptr) {}

Parent::~Parent() = default;

// Child.cpp
#include "Child.h"
#include <iostream>

class Child::Impl : public Parent::Impl {
public:
    void doSomething() override {
        std::cout << "Child is doing something!" << std::endl;
    }
};

Child::Child() : pImpl(std::make_unique<Impl>()) {
    // 将子类的Pimpl实例传递给父类
    Parent::pImpl = std::move(pImpl);
}

Child::~Child() = default;

void Child::doSomething() {
    pImpl->doSomething();
}

// main.cpp
#include "Child.h"

int main() {
    Child child;
    child.doSomething();
    return 0;
}