public static HashSet<string> GetReservedWordsFromTokenizer()
{
    // Get the assembly containing Tokenizer
    var asm = typeof(Token).Assembly;

    // Get the internal Tokenizer type
    var tokenizerType = asm.GetType("System.Management.Automation.Language.Tokenizer");

    // Get the private static readonly field s_keywordTokenKind
    var field = tokenizerType.GetField("s_keywordTokenKind", BindingFlags.NonPublic | BindingFlags.Static);

    // Get the TokenKind[] value
    var tokenKinds = field.GetValue(null) as Array;

    var reservedWords = new HashSet<string>(
        tokenKinds.Cast<Enum>().Select(tk => tk.ToString()),
        StringComparer.OrdinalIgnoreCase
    );

    return reservedWords;
}