Is Type name = name; ever useful in C++?

Question

The following code is allowed in C++:

int a = a;

or

Type name = name;

Both lead to an uninitialized object being initialized by itself, which often leads to undefined behavior.

Is such code ever needed or reasonable? Are there cases of such code being useful?

Answer 1

This reminded me of an old thread of the GCC mailing list in which Gabriel Dos Reis gave the following example to construct a one-node circular list:

struct Node {
  Node* link;
  Node(Node& n) : link(&n) { }
};

int main()
{
  Node x = x;
}

Answer 2

You are allowed to use the name of the variable in its initializer. The code

Type name = name;

is probably not useful, but the code

Type name = f(&name);

might be.

There are many places where the language syntax doesn't forbid useless constructs. :-)