#nullable enable

using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

    static void patternCheck(string[]? items) {

        if (items is [..]) {

           // See, no warning here.

        }

    }

​

    static void countCheck(string[]? items) {

        if (items.Length > 0) {

            // Warning here! items might be null. Calling items.length would result in a null refference exception!

        }

    }

}