I am seeing that it chokes on Action<> delegate. This code:
public class Class1: Intro
/// <inheritdoc />
public void Method(Action<int, int> i)
throw new NotImplementedException();
public interface Intro
/// SOme method.
void Method(Action<int, int> i);
Will result in no members generated for interface Intro nor any method from Intro will be visible in Class1. I've found that the problem is caused by Action<> delegate. Once I remove it everything works fine (in .net <4.0 it works as expected).
Hopefully the update will solve this issue.