Method assign

dlib/optional.h:188–197

            template<class Optional>
            constexpr void assign(Optional&& rhs) noexcept(std::is_nothrow_constructible<T,Optional>::value &&
                                                           std::is_nothrow_assignable<T&,Optional>::value)
            {
                if (this->active && rhs.active)
                    this->val = std::forward<Optional>(rhs).val;
                else if (!this->active && rhs.active)
                    construct(std::forward<Optional>(rhs).val);
                else if (this->active && !rhs.active)
                    destruct();
            }

            constexpr void destruct() noexcept(std::is_nothrow_destructible<T>::value)
            {