using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

​

    }

}

​

class X<T> : X<T>.IX<T>

{

​

    private interface IX<out TInner>

    { // the private covariant interface

        void foo();

    }

​

    // It grants access to the private method `foo`

    private T foo() { throw new NotImplementedException(); }

    void X<T>.IX<T>.foo() { throw new NotImplementedException(); }

​

    private static void someMethod(IX<T> x)

    {

        // Here I can use `x` covariantly

    }

}

​