static void Main(string[] args)
{
MyNode n = new MyNode();
MyContainer c = new MyContainer();
c.AddChild(n);
OtherNode o = new OtherNode();
o.AddChild(o);
}
static void Main(string[] args)
{
MyNode n = new MyNode();
MyContainer c = new MyContainer();
c.AddChild(n);
MySubNode s = new MySubNode();
//
// This does not work because it tries to fill the generic in the
// extension method with <MySubNode, MyContainer>, which does not
// fulfil the constraint "where Container : Node".
//
//c.AddChild(s);
OtherNode o = new OtherNode();
o.AddChild(o);
}