class ActionDispatch::Routing::Mapper::Mapping

def normalize_options!
  path_without_format = @path.sub(/\(\.:format\)$/, '')
  if using_match_shorthand?(path_without_format, @options)
    to_shorthand    = @options[:to].blank?
    @options[:to] ||= path_without_format.gsub(/\(.*\)/, "")[1..-1].sub(%r{/([^/]*)$}, '#\1')
  end
  @options.merge!(default_controller_and_action(to_shorthand))
  requirements.each do |name, requirement|
    # segment_keys.include?(k.to_s) || k == :controller
    next unless Regexp === requirement && !constraints[name]
    if requirement.source =~ ANCHOR_CHARACTERS_REGEX
      raise ArgumentError, "Regexp anchor characters are not allowed in routing requirements: #{requirement.inspect}"
    end
    if requirement.multiline?
      raise ArgumentError, "Regexp multiline option not allowed in routing requirements: #{requirement.inspect}"
    end
  end
end