Move constructor and assignment operator: why no default for derived classes?
- by doublep
Why there is default move constructor or assignment operator not created for derived classes? To demonstrate what I mean; having this setup code:
#include <utility>
struct A
{
A () { }
A (A&&) { throw 0; }
A& operator= (A&&) { throw 0; }
};
struct B : A
{ };
either of the following lines throws:
A x (std::move (A ());
A x; x = A ();
but neither of the following does:
B x (std::move (B ());
B x; x = B ();
In case it matters, I tested with GCC 4.4.
