[]IPAddr{
			{IP: IPv6loopback},
			{IP: ParseIP("fe80::1"), Zone: "eth0"},
		},
		testInetaddr,
		&TCPAddr{IP: IPv6loopback, Port: 5682},
		addrList{
			&TCPAddr{IP: IPv6loopback, Port: 5682},
			&TCPAddr{IP: ParseIP("fe80::1"), Port: 5682, Zone: "eth0"},
		},
		nil,
		nil,
	},
	{
		nil,
		[]IPAddr{
			{IP: IPv4(127, 0, 0, 1)},
			{IP: IPv4(192, 168, 0, 1)},
			{IP: IPv6loopback},

		resolveUDPAddrTests = append(resolveUDPAddrTests, resolveUDPAddrTest{"udp6", "localhost:3", &UDPAddr{IP: IPv6loopback, Port: 3}, nil})
		resolveIPAddrTests = append(resolveIPAddrTests, resolveIPAddrTest{"ip6", "localhost", &IPAddr{IP: IPv6loopback}, nil})

		// Issue 20911: don't return IPv4 addresses for

		{"udp", "golang.org"},
	}
	results := map[[2]string][]IPAddr{
		{"udp", "golang.org"}: {
			{IP: IPv4(127, 0, 0, 1)},
			{IP: IPv6loopback},
		},
		{"udp4", "golang.org"}: {
			{IP: IPv4(127, 0, 0, 1)},
		},
		{"udp6", "golang.org"}: {
			{IP: IPv6loopback},
		},
	}
	calls := int32(0)
	waitCh := make(chan struct{})

		{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To4()}, nil},
		{"tcp4", "127.0.0.1", &TCPAddr{IP: ParseIP("127.0.0.1").To16()}, nil},
		{"tcp4", "127.0.0.1", &TCPAddr{IP: IPv6loopback}, errNoSuitableAddress},
		{"tcp4", "127.0.0.1", &UDPAddr{}, &AddrError{Err: "some error"}},
		{"tcp4", "127.0.0.1", &UnixAddr{}, &AddrError{Err: "some error"}},

		{"tcp6", "::1", nil, nil},

	return nil
}

func newDualStackListener() (lns []*TCPListener, err error) {
	var args = []struct {
		network string
		TCPAddr
	}{
		{"tcp4", TCPAddr{IP: IPv4(127, 0, 0, 1)}},
		{"tcp6", TCPAddr{IP: IPv6loopback}},
	}
	for i := 0; i < 64; i++ {
		var port int
		var lns []*TCPListener
		for _, arg := range args {
			arg.TCPAddr.Port = port
			ln, err := ListenTCP(arg.network, &arg.TCPAddr)
			if err != nil {

		}
	}

	var isloopback bool
	switch ra := ra.(type) {
	case *syscall.SockaddrInet4:
		isloopback = ra.Addr[0] == 127
	case *syscall.SockaddrInet6:
		isloopback = ra.Addr == [16]byte(IPv6loopback)
	default:
		panic("unexpected type in connect")
	}
	if isloopback {
		// This makes ConnectEx() fails faster if the target port on the localhost
		// is not reachable, instead of waiting for 2s.

		{
			name:     "loopback v4Addr",
			ip:       loopback4,
			loopback: true,
		},
		{
			name:     "loopback v6Addr",
			ip:       IPv6Loopback(),
			loopback: true,
		},
		{
			name:     "loopback v6 mapped v4Addr",
			ip:       AddrFrom16(IPv6Loopback().As16()),
			loopback: true,
		},
		{
			name:                    "interface-local multicast v6Addr",
			ip:                      ilm6,

)

// Well-known IPv6 addresses
var (
	IPv6zero                   = IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
	IPv6unspecified            = IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
	IPv6loopback               = IP{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
	IPv6interfacelocalallnodes = IP{0xff, 0x01, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01}

	{IPv4allrouter, true, false},
	{IPv4zero, true, false},
	{IPv4(224, 0, 0, 1), true, false},
	{IPv4(127, 0, 0, 1), true, false},
	{IPv4(240, 0, 0, 1), true, false},
	{IPv6unspecified, false, true},
	{IPv6loopback, false, true},
	{IPv6interfacelocalallnodes, false, true},
	{IPv6linklocalallnodes, false, true},
	{IPv6linklocalallrouters, false, true},
	{ParseIP("ff05::a:b:c:d"), false, true},

//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname loopbackIP
func loopbackIP(net string) IP {
	if net != "" && net[len(net)-1] == '6' {
		return IPv6loopback
	}
	return IP{127, 0, 0, 1}