C++ overload resolution with local lambda and global functions

demo.cpp

#include <typeinfo>
#include <iostream>
#include <string>

namespace {

struct Something {
};

template <typename T>
void process(const T& x, Something const& s)
{
    std::cerr << "Processing " << typeid(T).name() << std::endl;
}

struct A {
};

void process(A const& p, Something const& s)
{
    std::cout << "A" << std::endl;
}

struct B {
};

void process(B const& p, Something const& s)
{
    std::cout << "B" << std::endl;
}
} // namespace


template<class... T> struct overloaded : T... { using T::operator()...; };
template<class... T> overloaded(T...) -> overloaded<T...>;

int main()
{
    struct C {};

    auto process = overloaded{
        [](C const& p, Something const& s) {
            std::cerr << "Processing C" << std::endl;
        },
        [](const auto& p, Something const& s){::process(p, s);}
    };


    Something s{};

    A a{};
    B b{};
    C c{};

    process(a, s);
    process(b, s);
    process(c, s);
}