using System;

using System.Collections.Generic;

​

public class Trait

{

    public List<Trait> conflicting_traits = new List<Trait>();

}

​

public class DerivedTrait : Trait

{

}

​

public class DerivedTrait2 : Trait

{

}

​

public class Test

{

    public List<Trait> _traits = new List<Trait>();

    public bool AddTrait<T>() where T : new()

    {

        foreach(var trait in _traits) {

            if(trait is T) {

                return false;

            }

            foreach(var conflict in trait.conflicting_traits) {

                if(conflict is T) {

                    return false;

                }

            }

        }

​

        T instanced = new T();

        _traits.Add((Trait)(object)instanced);

        return true;

    }

}

​

public class Program

{

    public static void Main()

    {

        var test = new Test();

        if(test.AddTrait<DerivedTrait>()) {

            Console.WriteLine("Yup");

        }

        if(!test.AddTrait<DerivedTrait>()) {

            Console.WriteLine("Nope");

        }

        if(test.AddTrait<DerivedTrait2>()) {

            Console.WriteLine("Yup");

        }

        foreach(var trait in test._traits) {

            Console.WriteLine(trait.GetType().Name);

        }

    }

}