template-universal-constructor.cpp

#include <iostream>
using namespace std;

struct Foo {
    Foo() = default;

    Foo(const Foo&) { cout << "Foo::Foo(const Foo&)" << endl; }
    Foo(Foo&&) { cout << "Foo::Foo(Foo&&)" << endl; }
    template<class T> Foo(T&&) { cout << "Foo::Foo<T>(T&&)" << endl; }
};

int main() {
    auto f = Foo{};
    const auto copy_f = f;
    auto copy_copy_f = copy_f;
}