using System;

using System.Diagnostics;

public class Program

{

    interface IReadOnlyInterface

    {

        int SomeProp { get; }

    }

    interface IReadWriteInterface : IReadOnlyInterface

    {

        new int SomeProp { get; set; }

    }

    class ReadWriteClass : IReadWriteInterface

    {

        public int SomeProp { get; set; }

    }

    public static void Main()

    {

        var readWrite = new ReadWriteClass() { SomeProp = 100 };

        IReadOnlyInterface read = readWrite;

        Console.WriteLine(read.SomeProp);

    }

}