Possible mono bug: IList.Contains does automatic/implcit conversion between enums (or casts to int).

mono-bug.txt

using System;
using System.Collections;
using System.Collections.Generic;

namespace Test {
	enum Set {
		One = 1,
		Two = 2,
		Three = 3
	}
	
	enum ItemOne {
		One = 1
	}
	
	class Dummy {
		static public void Main() {
			var list = new List<Set>();
			list.Add(Set.One);
			
			Console.WriteLine(((IList)list).Contains(ItemOne.One)); 
		}
	}
}