IPAddr#end_addr

# File tmp/rubies/ruby-3.4.1/lib/ipaddr.rb, line 541
def end_addr
  case @family
  when Socket::AF_INET
    @addr | (IN4MASK ^ @mask_addr)
  when Socket::AF_INET6
    @addr | (IN6MASK ^ @mask_addr)
  else
    raise AddressFamilyError, "unsupported address family"
  end
end