Are C++ recursive type definitions possible, in particular can I put a vector within the definition of T?

Question

For one of my projects, what I really wanted to do was this (simplifying it to the bare minimum);

struct Move
{
    int src;
    int dst;
};

struct MoveTree         


        

Answer 1

The C++ Standard (2003) clearly says that instantiating a standard container with an incomplete type, invokes undefined-behavior.

The spec says in §17.4.3.6/2,

In particular, the effects are undefined in the following cases:

__ [..]
— if an incomplete type (3.9) is used as a template argument when instantiating a template component.
__ [..]