#include <algorithm>
#include <functional>
#include <iostream>
#include <memory>
#include <string>
#include <type_traits>
#include <utility>
 
 
class A : public std::enable_shared_from_this<A>
{};
 
class B : public A
{
public:
	void doReallyCoolStuff();
}; 
 
void doCoolStuff(std::weak_ptr<A> obj)
{
	std::cout << "cool A\n";
}
 
void doCoolStuff(std::weak_ptr<B> obj)
{
	std::cout << "cool B\n";
 doCoolStuff(std::static_pointer_cast<A>(obj.lock()));
}
 
void B::doReallyCoolStuff()
{
	doCoolStuff(std::weak_ptr<B>(std::static_pointer_cast<B>(shared_from_this())));
}
 
int main()
{
	auto b = std::make_shared<B>();
	b->doReallyCoolStuff();
}

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