I will give the first person to correctly explain why this compiles a nice compliment

#include <iostream>

class A {};

int main() {
  std::cout << &(A() = a) << "\n"; 
}

Oops there is missing declaration of the variable a. This is what you should be examining:

#include

class A {};

int main() {
A a;
std::cout << &(A() = a) << "\n";
}

@wallhackio Now it won't compile because there's nothing after the include: