using System;

using System.Collections.Generic;

using System.Linq;

​

​

public static class extensions{

     public static IEnumerable<T> NotNull<T>(this IEnumerable<T> enumerable)

    {

        return enumerable.Where(e => e != null);

    }

}

​

public class Program

{

    public class Test{

        public string Prop1 {get;set;}

    }

    public static void Main()

    {

        List<Test?> objs = new List<Test?>

        {

            new Test(),

            null,

            new Test()

        };

​

        // This will not compile because the type is List<MyObject?>

        List<Test> filtered = objs.NotNull<Test?>().ToList();

        Console.WriteLine(filtered.Count);

    }

}