using System;
using System.Collections.Generic;

namespace AddingReversedNumbers
{
	public class MyDerivedClass : MyBaseClass, IMyInterface
	{
		public int InterfaceProperty { get; set; }
		public int DerivedClassProperty { get; set; }
		public List<int> DerivedClassList { get; set; }
	}
	
	public class MyBaseClass
	{
		public int BaseClassProperty { get; set; }
	}
	
	public interface IMyInterface
	{
		int InterfaceProperty { get; set; }
	}
	
	
	class Program
	{
		static void Main()
		{
			//// This code works just fine.
			//var derivedList = new List<MyDerivedClass>();
			//derivedList.Add(new MyDerivedClass { BaseClassProperty = 10, DerivedClassProperty = 20, InterfaceProperty = 30 });
			//derivedList.Add(new MyDerivedClass { BaseClassProperty = 20, DerivedClassProperty = 40, InterfaceProperty = 60 });
			//var baseList = derivedList.ConvertAll(x => (MyBaseClass)x);
			
			// This code breaks when ConvertAll() is called.
			var baseList = new List<MyBaseClass>();
			baseList.Add(new MyBaseClass{ BaseClassProperty = 10 });
			baseList.Add(new MyBaseClass{ BaseClassProperty = 20 });
			var derivedList = baseList.ConvertAll(x => (MyDerivedClass)x);
		}
	}
}