using static System.Console;

using System.Collections;

using System.Collections.Generic;

​

public class Program {

    public static void Main() {

        var x = new MyClasst<int>();

        WriteLine(((IEnumerable)x).GetEnumerator());

        WriteLine(x.GetEnumerator());

    }

}

​

public class MyClasst<T> : IEnumerable<T> {

    private T[] list;

    public IEnumerable Teste() => (IEnumerable)GetEnumerator();

​

    IEnumerator IEnumerable.GetEnumerator() {

        WriteLine("Explícita");

        return this.GetEnumerator();

    }

​

    public IEnumerator<T> GetEnumerator() {

​

        yield return this.list[0];

    }

}