Why is "A & a = a" valid?

Question

#include <iostream>
#include <assert.h>

using namespace std;

struct Base
{
  Base() : m_member1(1) {}

  Base(const Base & other) 
  { 
    assert(this != &other);   // this should trigger
    m_member1 = other.m_member1; 
  }

  int m_member1;
};

struct Derived
{
  Derived(Base & base) : m_base(m_base) {} // m_base(base)

  Base & m_base;
};

void main()
{
  Base base;

  Derived derived(base);

  cout << derived.m_base.m_member1 << endl; // crashes here
}

The above example is a synthesized version of a foggy constructor. I used the link from a member of the class Derived::m_basebecause I wanted to make sure that the element would be initialized by calling the constructor. One of the problems is that neither GCC nor MSVC give me a warning in m_base(m_base). But for me, the more serious thing is that the statement finds everything good, and the application crashes later (sometimes far from an error). Question: Is it possible to indicate such errors?

Answer 1

, Base m_base(m_base). Base& m_base. , m_base Base m_base.

, ​​ , . gcc -Wunused-parameter -Wextra -Wunused.