dynamic_cast with unique_ptr

dynamiccastunique.cpp

#include <iostream>
#include <memory>

struct A
{
	virtual ~A() {}
};

struct B : public A
{
	
};

int main()
{
	std::unique_ptr<B> b(new B);
	std::unique_ptr<A> a(b.release());

	std::unique_ptr<A> a1(new B);
	std::unique_ptr<B> b1(dynamic_cast<B*>(a1.release()));

	// Error
	//std::unique_ptr<A> a2(new B);
	//std::unique_ptr<B> b2(a1.release());

	return 0;
}

Yeah OK, so in general this approach could leak, that's true.
Thanks for the clarification.