namespace System.Text.RegularExpressions
{
    [EditorBrowsable(EditorBrowsableState.Never)]
    public abstract class RegexRunner
    {
        [Obsolete("This API supports obsolete mechanisms for Regex extensibility. It is not supported.", DiagnosticId = "SYSLIB0052", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
        protected static bool CharInSet(char ch, string! set, string! category);
    }
}