static File byteCodePathForClass_forURLClassLoader(Class c) ctex {
  if (c == null) null;
  ClassLoader cl = getClassLoader(c);
  
  if (cl cast URLClassLoader) {
    S name = c.getName().replace('.', '/') + ".class";
    var urls = cl.getURLs();
    for (URL url : urls) pcall {
      File location = urlToFile(url);
      temp InputStream in = inputStreamForFileInDirOrZip(location, name);
      if (in != null) ret location;
    }
    fail(name + " not found in: " + urls);
  }
  
  null;
}

Began life as a copy of #1033452