What does this program print when the platform source generator is available?

using System;
using System.Text.RegularExpressions;

Console.WriteLine(CodeRules.IsValid("AB123"));
Console.WriteLine(CodeRules.IsValid("ab123"));

public static partial class CodeRules
{
    [GeneratedRegex("^[A-Z]{2}[0-9]{3}$", RegexOptions.CultureInvariant)]
    private static partial Regex CodePattern();

    public static bool IsValid(string value) => CodePattern().IsMatch(value);
}