Given a base class with the following interface:

public class Base
{
    public virtual IEnumerable<string> GetListOfStuff()
    {
        yield return "First";
        yield return "Second";
        yield return "Third";
    }
}

I want to make a derived class that overrides the method, and adds its own stuff, like so:

public class Derived : Base
{
    public override IEnumerable<string> GetListOfStuff()
    {
        foreach (string s in base.GetListOfStuff())
        {
            yield return s;
        }

        yield return "Fourth";
        yield return "Fifth";
    }
}

However, I'm greeted with a warning that "access to a member through a base keyword from an iterator cannot be verified".

What's the accepted solution to this problem then?