anchor.diff:  ----
   This produces the following usage help:
   ----
  -Usage: <main class> -l=<lang> -o=<option>
  +Usage: <main class> [-l=<lang>] [-o=<option>]
     -l=<lang>     Enum values: java, groovy, kotlin, javascript, frege, clojure
     -o=<option>   Candidates: A, B, C
   ----
  
positive.code: import java.io.File;
  
  class Convert {
      @Option(names = "-patterns", description = "the regex patterns to use");
      Pattern[] patterns;
  
      @Parameters(/* type = File.class, */ description = "the files to convert")
  
negative.code: [source, java]
  ----
  class BothOptionAndParametersMandatory {
      @Parameters(arity = "1..*", description = "at least one File")
      File[] files;
  
      @Option(names = "-n", required = true, description = "mandatory number")
  