G++ 编译器错误？

Question

Here is what my code looks like which is very simple:

#include <stdio.h>

class Test
{
public:
   Test()
   {
      printf ("contructor !\n");
   }

   ~Test()
   {
      printf ("destructor !\n");
   }

   Test(const Test& test)
   {
      printf ("copy contructor !\n");
   }
};


int main()
{
    Test xyz(xyz);
    return 0;
}

Then I type g++ a.cpp; ./a.out

It output: copy contructor ! destructor !

but no contructor output !
I`m confused, is it a bug of compiler?

see pic

Answer 1

In the line where you create the object xyz the address of this object in known even before the object is created. That means that you may take the reference to this (not created yet) object and pass it as a parameter to the constructor of this object itself. From the compiler point of view it is possible. You don't initialize any fields, so you don't observe any fields initialized with junk. Anyway, you get what you deserve.

Is that just a theoretical question or you really have a practical purpose?