using System;

​

​

public class Program

{

    interface IP {}

    class P<IN, OUT> : IP

    {

        public IN In { get; set; }  

    }

    void main()

    {

        IP a = new P<int, string>() { In = 123 };

        Type t = a.GetType();

        Console.WriteLine(t.GetGenericArguments()[1]);

        if (t.GenericTypeArguments[1] == typeof(string))

        {

            P<dynamic, string> p = System.Runtime.CompilerServices.Unsafe.As<P<dynamic, string>>(a);

            Console.WriteLine(p == null);

            Console.WriteLine(p.In);

        }

    }

​

    public static void Main()

    {

        new Program().main();

    }

}