gistfile1.cs

using System;
using System.Reflection;

class Program
{
    static void Main()
    {
        var allocate = typeof (RuntimeTypeHandle).GetMethod("Allocate", (BindingFlags) 40);
        var open = allocate.Invoke(null, new[] {typeof (C<>.E)});
        Console.WriteLine(open.GetType());
    }
}

class C<T>
{
    public enum E { }
}