using System;

using System.Collections.Generic;

​

// some class which has a method that _does stuff_

public class Foo

{

    public void DoThing()

    {

        Console.WriteLine("I did a thing!");

    }

}

public class Program

{

    public static void Main()

    {

        // list of Foo we'd want to eventually _do stuff_ with

        List<Foo> fooList = new();

        // we could do this currently by going

        fooList.ForEach(f => f.DoThing());

        // but what about in the form (this is currently invalid)

        fooList.GetAll().DoThing();

        // the above could be made to work by uising the following bastadised extension methods but it is not DRY

        // add a GetAll only for a List of Foo. This sucks since it's not really "getting all" jsut returning an enumerator.

        // public static List<T>.Enumerator GetAll<T>(this List<T> list) where T : Foo

        // {

        //     return dictionary.GetEnumerator();

        // }

        // this also sucks since instead of being able to call the existing DoThing we redefine it (and now have to keep it in-sync)

        // public static void DoThing<T>(this List<T>.Enumerator listEnum) where T : Foo

        // {

        //     while (listEnum.MoveNext())

        //     {

        //         listEnum.Current.Value.DoThing();

        //     }

        // }

    }

}