MethodAccessException on CF 2.0 List<T>.Sort

public static class LibraryClass
{
    public static void Test<T>(T foo, T bar)
    {
        // vastly simplified... I am aware that it is already in order here ;-p
        var list = new List<Wrapper<T>>();
        list.Add(new Wrapper<T> { Tag = 1, Value = foo });
        list.Add(new Wrapper<T> { Tag = 2, Value = bar });

        list.Sort((x,y) => x.Tag.CompareTo(y.Tag)); // BOOM!!
    }
}

public class Wrapper<T> // public to prove this isn't a factor...
{
    public T Value { get; set; }
    public int Tag { get; set; }
}

public static class Program
{
    static void Main()
    {
        MyData foo = new MyData {Name = "foo"},
            bar = new MyData {Name = "bar"};

        LibraryClass.Test<MyData>(foo, bar);
    }
}

class MyData // but make MyData public and it works...
{
    public string Name { get; set; }
}