wrong way of using std::max

wrong_max.cc

#include <algorithm>
#include <iostream>
struct C{
    int v{};
    C(int v_):v{v_}{
        std::cout << "C()[" << v << "]\n";
    }
    C(const C &)=delete;
    bool operator<(C const & o) const{
        return v < o.v;
    }
    C & operator=(const C &)=delete;
    ~C(){
        std::cout << "~C()[" << v << "]\n";
        v = 42;
    }
};

C foo(){
    return {2};
}

int main(){
    C a{1};
    C const & c = std::max(a, foo());
    std::cout << c.v << "\n";
    return 0;
}