class Parser::Builders::Default

def arg_name_collides?(this_name, that_name) 

def arg_name_collides?(this_name, that_name)
  case @parser.version
  when 18
    this_name == that_name
  when 19
    # Ignore underscore.
    this_name != :_ &&
      this_name == that_name
  else
    # Ignore everything beginning with underscore.
    this_name[0] != '_' &&
      this_name == that_name
  end
end