using System;

​

public abstract class cl<T> where T:cl<T>

{

public cl(){}

​

public abstract void test();

public void make()

{

this.test();

}

}

​

public class cl2<T>:cl<cl2<int>> 

{

public cl2(){}

public override void test()

{

Console.WriteLine("test1");

}

}

​

public class Program

{

    public static void Main()

    {

        var a=new cl2<int>();

    a.make();

    }

}