Operator overloading is happening in this question but the number of arguments and type is same

The following code should generate compilation error according to me. Because I think the compiler might be confused to know which foo() to call.

#include <iostream> 

typedef long long ll;

void foo(unsigned ll) {
    std::cout << "1";
}

void foo(unsigned long long) {
    std::cout << "2";
}

int main() {
    foo(2ull);
}