using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Test.Two.HasFlag(Test.None));

        Console.WriteLine(Contains(Test.Three, Test.One));

    }

    public static bool Contains<T>(T types, T type) where T : Enum

    {

        TypeCode typeCode = types.GetTypeCode();

        switch(typeCode)

        {

            case TypeCode.Int32:

                int typeInt = (int)(object)type;

                int typesInt = (int)(object)types;

                if(typeInt == 0)

                {

                    return typesInt == 0;

                }

                return (typesInt & typeInt) == typeInt;

​

            default:

                return false;

        }

    }

    public enum Test

    {

        None = 0,

        One = 1,

        Two = 2,

        Four = 4,

        Three = One | Two,

    }

}