C++-如何返回协变类列表?

我正在处理Qt+C++(x11)。

我有一个基类和几个子类,它们返回一个指向该子类的新指针(协变)。我也需要返回这些子类的容器(QList)。举个例子:

class A
{
public:
    int id;
}

class B : public A
{
    int Age;
};

class WorkerA
{
public:
    virtual A *newOne() {return new A()};
    virtual QList<A*> *newOnes {
        QList<A*> list = new QList<A*>;
        //Perform some data search and insert it in list, this is only simple example. In real world it will call a virtual method to fill member data overriden in each subclass.
        A* a = this.newOne();
        a.id = 0;
        list.append(this.newOne()); 
        return list;
        };        
};

class WorkerB
{
public:
    virtual B *newOne() override {return new B()}; //This compiles OK (covariant)
    virtual QList<B*> *newOnes override { //This fails (QList<B*> is not covariant of QList<A*>)
        (...)
        };        
};

这将无法编译,因为QList与QList的类型完全不同。但类似的东西会很好。在现实世界中,B将比A有更多的数据成员,并且会有C、D……,因此需要对列表的返回进行“协变”。我会变得更好:

WorkerB wb;
//some calls to wb...
QList<B*> *bList = wb.newOnes();
B* b = bList.at(0); //please excuse the absence of list size checking
info(b.id);
info(b.age);

比

WorkerB wb;
//some calls to wb...
QList<A*> *bList = wb.newOnes();
B* b = static_cast<B*>(bList.at(0)); //please excuse the absence of list size checking
info(b.id);
info(b.age);

有什么方法可以实现这一点吗?