// and ipv6only. It returns every address when the filter is nil.
// The result contains at least one address when error is nil.
func filterAddrList(filter func(IPAddr) bool, ips []IPAddr, inetaddr func(IPAddr) Addr, originalAddr string) (addrList, error) {
	var addrs addrList
	for _, ip := range ips {
		if filter == nil || filter(ip) {
			addrs = append(addrs, inetaddr(ip))
		}
	}

		for _, a := range addrs {
			if a == addr {
				continue loop
			}
		}
		addrs = append(addrs, addr)
	}
	return
}

func (r *Resolver) lookupIP(ctx context.Context, network, host string) (addrs []IPAddr, err error) {
	if order, conf := systemConf().hostLookupOrder(r, host); order != hostLookupCgo {
		return r.goLookupIP(ctx, network, host, order, conf)
	}

	lits, err := r.lookupHost(ctx, host)
	if err != nil {

func hasRoutableIP(network string, ifi *net.Interface) (net.IP, bool) {
	ifat, err := ifi.Addrs()
	if err != nil {
		return nil, false
	}
	for _, ifa := range ifat {
		switch ifa := ifa.(type) {
		case *net.IPAddr:
			if ip, ok := routableIP(network, ifa.IP); ok {
				return ip, true
			}
		case *net.IPNet:
			if ip, ok := routableIP(network, ifa.IP); ok {
				return ip, true
			}
		}
	}
	return nil, false

		t.Fatalf("%s.  Unable to get IP addresses of this host.", err)
	}

	for _, addr := range addrs {
		var ip net.IP
		switch v := addr.(type) {
		case *net.IPNet:
			ip = v.IP
		case *net.IPAddr:
			ip = v.IP
		}

		if ip.To4() != nil {
			localIP4.Add(ip.String())
		}
	}

	// Filter ipList by IPs those do not start with '127.'.

//   net.IP:     24 byte slice header + {4, 16} = 28 to 40 bytes
//   net.IPAddr: 40 byte slice header + {4, 16} = 44 to 56 bytes + zone length
//   netip.Addr: 24 bytes (zone is per-name singleton, shared across all users)

// Addr represents an IPv4 or IPv6 address (with or without a scoped
// addressing zone), similar to [net.IP] or [net.IPAddr].
//
// Unlike [net.IP] or [net.IPAddr], Addr is a comparable value

	}

	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return err
	}
	for _, addr := range addrs {
		var ip net.IP
		switch v := addr.(type) {
		case *net.IPNet:
			ip = v.IP
		case *net.IPAddr:
			ip = v.IP
		}
		if ip != nil && ip.Equal(nodeIP) {
			return nil
		}
	}
	return fmt.Errorf("node IP: %q not found in the host's network interfaces", nodeIP.String())
}

	ctx := context.WithValue(context.Background(), nettrace.LookupIPAltResolverKey{}, func(ctx context.Context, network, host string) ([]net.IPAddr, error) {
		if host != "dns-is-faked.golang" {
			t.Errorf("unexpected DNS host lookup for %q/%q", network, host)
			return nil, nil
		}
		return []net.IPAddr{{IP: net.ParseIP(ip)}}, nil
	})

	body := "some body"

		return base, offset
	}
	p1, off1 := baseAndOffset(p1)
	p2, off2 := baseAndOffset(p2)
	if isSamePtr(p1, p2) {
		return !overlap(off1, n1, off2, n2)
	}
	// p1 and p2 are not the same, so if they are both OpAddrs then
	// they point to different variables.
	// If one pointer is on the stack and the other is an argument
	// then they can't overlap.
	switch p1.Op {
	case OpAddr, OpLocalAddr: