overload "+" for std::move

move-identity.cc

#include <utility>
#include <iostream>
using std::cout;
using std::endl;

// move-identity
template <class T> T&& operator+(T& x) { return std::move(x); }

struct foo
{
	foo() = default;
	foo(foo const&) { cout << "copy" << endl; }
	foo(foo     &&) { cout << "move" << endl; }
};

int main()
{
	foo bar;
	foo bay =  bar;
	foo baz = +bar;
}