Invalid Code

public class Iterator<G> {
	public bool next () {
		return true;
	}

	public G get (int arg) {
		return (G)null;
	}
}

public class Test<G> {
	public Iterator<G> iterator () {
		return new Iterator<G> ();
	}
}

void main () {
	Test<string?> test = null;
	foreach (var t in test) {
	}
}