Make unique with cast

make_unique_as.cpp

#include <iostream>
#include <memory>
#include <type_traits>

class Base
{
public:
    virtual void foo() const = 0;
};

class Derived
    : public Base
{
private:
    int i;

public:
    explicit
    Derived(int _i)
        : i(_i)
    {}

    virtual void foo() const override
    {
        std::cout << __PRETTY_FUNCTION__ << ' ' << i << '\n';
    }
};

template <class BaseT, class DerivedT, typename... Args>
std::enable_if_t<std::is_convertible<DerivedT*,BaseT*>::value, std::unique_ptr<BaseT>> make_unique_as(Args&&... args)
{
    return std::make_unique<DerivedT>(std::forward<Args>(args)...);
}

int main()
{
    const auto obj = make_unique_as<Base, Derived>(5);
    obj->foo();
}