using System.Collections.Generic;
public class A : Super { }
public string foo { get; set; }
public static void Main(string[] args)
var listA = new List<A>{new A{foo = "toto"}};
var listSuper = new List<Super>{new Super{foo = "bar"}};
var bothSuper = listA.Concat(listSuper).ToList();
var bothA = listSuper.Concat(listA).ToList();