class ActionDispatch::Journey::Formatter::MissingRoute

def message
  message = +"No route matches #{Hash[constraints.sort_by { |k, v| k.to_s }].inspect}"
  message << ", missing required keys: #{missing_keys.sort.inspect}" if missing_keys && !missing_keys.empty?
  message << ", possible unmatched constraints: #{unmatched_keys.sort.inspect}" if unmatched_keys && !unmatched_keys.empty?
  message
end