all: use any instead of interface{}

My favorite part of generics.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

chirp/chirp.go

@@ -80,7 +80,7 @@ func (b *BIRDClient) EnableProtocol(protocol string) error {
 // Reply codes starting with 0 stand for ‘action successfully completed’ messages,
 // 1 means ‘table entry’, 8 ‘runtime error’ and 9 ‘syntax error’.
 
-func (b *BIRDClient) exec(cmd string, args ...interface{}) (string, error) {
+func (b *BIRDClient) exec(cmd string, args ...any) (string, error) {
 	if _, err := fmt.Fprintf(b.conn, cmd, args...); err != nil {
 		return "", err
 	}

cmd/cloner/cloner.go

@@ -69,14 +69,14 @@ func main() {
 		gen(buf, imports, typ, pkg.Types)
 	}
 
-	w := func(format string, args ...interface{}) {
+	w := func(format string, args ...any) {
 		fmt.Fprintf(buf, format+"\n", args...)
 	}
 	if *flagCloneFunc {
 		w("// Clone duplicates src into dst and reports whether it succeeded.")
 		w("// To succeed, <src, dst> must be of types <*T, *T> or <*T, **T>,")
 		w("// where T is one of %s.", *flagTypes)
-		w("func Clone(dst, src interface{}) bool {")
+		w("func Clone(dst, src any) bool {")
 		w("	switch src := src.(type) {")
 		for _, typeName := range typeNames {
 			w("	case *%s:", typeName)
@@ -158,7 +158,7 @@ func gen(buf *bytes.Buffer, imports map[string]struct{}, typ *types.Named, thisP
 	fmt.Fprintf(buf, "// Clone makes a deep copy of %s.\n", name)
 	fmt.Fprintf(buf, "// The result aliases no memory with the original.\n")
 	fmt.Fprintf(buf, "func (src *%s) Clone() *%s {\n", name, name)
-	writef := func(format string, args ...interface{}) {
+	writef := func(format string, args ...any) {
 		fmt.Fprintf(buf, "\t"+format+"\n", args...)
 	}
 	writef("if src == nil {")

cmd/derpprobe/derpprobe.go

@@ -78,11 +78,11 @@ type overallStatus struct {
 	good, bad []string
 }
 
-func (st *overallStatus) addBadf(format string, a ...interface{}) {
+func (st *overallStatus) addBadf(format string, a ...any) {
 	st.bad = append(st.bad, fmt.Sprintf(format, a...))
 }
 
-func (st *overallStatus) addGoodf(format string, a ...interface{}) {
+func (st *overallStatus) addGoodf(format string, a ...any) {
 	st.good = append(st.good, fmt.Sprintf(format, a...))
 }
 
@@ -426,7 +426,7 @@ func probeNodePair(ctx context.Context, dm *tailcfg.DERPMap, from, to *tailcfg.D
 	}
 
 	// Receive the random packet.
-	recvc := make(chan interface{}, 1) // either derp.ReceivedPacket or error
+	recvc := make(chan any, 1) // either derp.ReceivedPacket or error
 	go func() {
 		for {
 			m, err := toc.Recv()

cmd/tailscale/cli/cert.go

@@ -79,7 +79,7 @@ func runCert(ctx context.Context, args []string) error {
 	}
 	domain := args[0]
 
-	printf := func(format string, a ...interface{}) {
+	printf := func(format string, a ...any) {
 		printf(format, a...)
 	}
 	if certArgs.certFile == "-" || certArgs.keyFile == "-" {

cmd/tailscale/cli/cli.go

@@ -35,7 +35,7 @@ import (
 var Stderr io.Writer = os.Stderr
 var Stdout io.Writer = os.Stdout
 
-func printf(format string, a ...interface{}) {
+func printf(format string, a ...any) {
 	fmt.Fprintf(Stdout, format, a...)
 }
 
@@ -44,7 +44,7 @@ func printf(format string, a ...interface{}) {
 //
 // It's not named println because that looks like the Go built-in
 // which goes to stderr and formats slightly differently.
-func outln(a ...interface{}) {
+func outln(a ...any) {
 	fmt.Fprintln(Stdout, a...)
 }
 
@@ -216,7 +216,7 @@ change in the future.
 	return err
 }
 
-func fatalf(format string, a ...interface{}) {
+func fatalf(format string, a ...any) {
 	if Fatalf != nil {
 		Fatalf(format, a...)
 		return
@@ -226,7 +226,7 @@ func fatalf(format string, a ...interface{}) {
 }
 
 // Fatalf, if non-nil, is used instead of log.Fatalf.
-var Fatalf func(format string, a ...interface{})
+var Fatalf func(format string, a ...any)
 
 var rootArgs struct {
 	socket string

cmd/tailscale/cli/status.go

@@ -136,7 +136,7 @@ func runStatus(ctx context.Context, args []string) error {
 	}
 
 	var buf bytes.Buffer
-	f := func(format string, a ...interface{}) { fmt.Fprintf(&buf, format, a...) }
+	f := func(format string, a ...any) { fmt.Fprintf(&buf, format, a...) }
 	printPS := func(ps *ipnstate.PeerStatus) {
 		f("%-15s %-20s %-12s %-7s ",
 			firstIPString(ps.TailscaleIPs),

cmd/tailscale/cli/up.go

@@ -192,7 +192,7 @@ type upOutputJSON struct {
 	Error        string `json:",omitempty"` // description of an error
 }
 
-func warnf(format string, args ...interface{}) {
+func warnf(format string, args ...any) {
 	printf("Warning: "+format+"\n", args...)
 }
 
@@ -823,8 +823,8 @@ func flagAppliesToOS(flag, goos string) bool {
 	return true
 }
 
-func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interface{}) {
+func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]any) {
-	ret := make(map[string]interface{})
+	ret := make(map[string]any)
 
 	exitNodeIPStr := func() string {
 		if !prefs.ExitNodeIP.IsZero() {
@@ -841,7 +841,7 @@ func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interfac
 		if preflessFlag(f.Name) {
 			return
 		}
-		set := func(v interface{}) {
+		set := func(v any) {
 			if flagAppliesToOS(f.Name, env.goos) {
 				ret[f.Name] = v
 			} else {
@@ -895,7 +895,7 @@ func prefsToFlags(env upCheckEnv, prefs *ipn.Prefs) (flagVal map[string]interfac
 	return ret
 }
 
-func fmtFlagValueArg(flagName string, val interface{}) string {
+func fmtFlagValueArg(flagName string, val any) string {
 	if val == true {
 		return "--" + flagName
 	}

cmd/tailscale/cli/web.go

@@ -313,7 +313,7 @@ func webHandler(w http.ResponseWriter, r *http.Request) {
 			AdvertiseExitNode bool
 			Reauthenticate    bool
 		}
-		type mi map[string]interface{}
+		type mi map[string]any
 		if err := json.NewDecoder(r.Body).Decode(&postData); err != nil {
 			w.WriteHeader(400)
 			json.NewEncoder(w).Encode(mi{"error": err.Error()})

cmd/testcontrol/testcontrol.go

@@ -46,10 +46,10 @@ type fakeTB struct {
 }
 
 func (t fakeTB) Cleanup(_ func()) {}
-func (t fakeTB) Error(args ...interface{}) {
+func (t fakeTB) Error(args ...any) {
 	t.Fatal(args...)
 }
-func (t fakeTB) Errorf(format string, args ...interface{}) {
+func (t fakeTB) Errorf(format string, args ...any) {
 	t.Fatalf(format, args...)
 }
 func (t fakeTB) Fail() {
@@ -61,17 +61,17 @@ func (t fakeTB) FailNow() {
 func (t fakeTB) Failed() bool {
 	return false
 }
-func (t fakeTB) Fatal(args ...interface{}) {
+func (t fakeTB) Fatal(args ...any) {
 	log.Fatal(args...)
 }
-func (t fakeTB) Fatalf(format string, args ...interface{}) {
+func (t fakeTB) Fatalf(format string, args ...any) {
 	log.Fatalf(format, args...)
 }
 func (t fakeTB) Helper() {}
-func (t fakeTB) Log(args ...interface{}) {
+func (t fakeTB) Log(args ...any) {
 	log.Print(args...)
 }
-func (t fakeTB) Logf(format string, args ...interface{}) {
+func (t fakeTB) Logf(format string, args ...any) {
 	log.Printf(format, args...)
 }
 func (t fakeTB) Name() string {
@@ -80,13 +80,13 @@ func (t fakeTB) Name() string {
 func (t fakeTB) Setenv(key string, value string) {
 	panic("not implemented")
 }
-func (t fakeTB) Skip(args ...interface{}) {
+func (t fakeTB) Skip(args ...any) {
 	t.Fatal("skipped")
 }
 func (t fakeTB) SkipNow() {
 	t.Fatal("skipnow")
 }
-func (t fakeTB) Skipf(format string, args ...interface{}) {
+func (t fakeTB) Skipf(format string, args ...any) {
 	t.Logf(format, args...)
 	t.Fatal("skipped")
 }

control/controlclient/auto.go

@@ -92,7 +92,7 @@ func NewNoStart(opts Options) (*Auto, error) {
 		return nil, err
 	}
 	if opts.Logf == nil {
-		opts.Logf = func(fmt string, args ...interface{}) {}
+		opts.Logf = func(fmt string, args ...any) {}
 	}
 	if opts.TimeNow == nil {
 		opts.TimeNow = time.Now

control/controlclient/direct.go

@@ -945,7 +945,7 @@ func (c *Direct) sendMapRequest(ctx context.Context, maxPolls int, cb func(*netm
 
 // decode JSON decodes the res.Body into v. If serverNoiseKey is not specified,
 // it uses the serverKey and mkey to decode the message from the NaCl-crypto-box.
-func decode(res *http.Response, v interface{}, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) error {
+func decode(res *http.Response, v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) error {
 	defer res.Body.Close()
 	msg, err := ioutil.ReadAll(io.LimitReader(res.Body, 1<<20))
 	if err != nil {
@@ -970,7 +970,7 @@ var jsonEscapedZero = []byte(`\u0000`)
 // decodeMsg is responsible for uncompressing msg and unmarshaling into v.
 // If c.serverNoiseKey is not specified, it uses the c.serverKey and mkey
 // to first the decrypt msg from the NaCl-crypto-box.
-func (c *Direct) decodeMsg(msg []byte, v interface{}, mkey key.MachinePrivate) error {
+func (c *Direct) decodeMsg(msg []byte, v any, mkey key.MachinePrivate) error {
 	c.mu.Lock()
 	serverKey := c.serverKey
 	serverNoiseKey := c.serverNoiseKey
@@ -1016,7 +1016,7 @@ func (c *Direct) decodeMsg(msg []byte, v interface{}, mkey key.MachinePrivate) e
 
 }
 
-func decodeMsg(msg []byte, v interface{}, serverKey key.MachinePublic, machinePrivKey key.MachinePrivate) error {
+func decodeMsg(msg []byte, v any, serverKey key.MachinePublic, machinePrivKey key.MachinePrivate) error {
 	decrypted, ok := machinePrivKey.OpenFrom(serverKey, msg)
 	if !ok {
 		return errors.New("cannot decrypt response")
@@ -1032,7 +1032,7 @@ func decodeMsg(msg []byte, v interface{}, serverKey key.MachinePublic, machinePr
 
 // encode JSON encodes v. If serverNoiseKey is not specified, it uses the serverKey and mkey to
 // seal the message into a NaCl-crypto-box.
-func encode(v interface{}, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) ([]byte, error) {
+func encode(v any, serverKey, serverNoiseKey key.MachinePublic, mkey key.MachinePrivate) ([]byte, error) {
 	b, err := json.Marshal(v)
 	if err != nil {
 		return nil, err
@@ -1310,7 +1310,7 @@ func (c *Direct) getNoiseClient() (*noiseClient, error) {
 	if nc != nil {
 		return nc, nil
 	}
-	np, err, _ := c.sfGroup.Do("noise", func() (interface{}, error) {
+	np, err, _ := c.sfGroup.Do("noise", func() (any, error) {
 		k, err := c.getMachinePrivKey()
 		if err != nil {
 			return nil, err

derp/derp_server.go

@@ -1641,8 +1641,8 @@ func (m multiForwarder) ForwardPacket(src, dst key.NodePublic, payload []byte) e
 	return fwd.ForwardPacket(src, dst, payload)
 }
 
-func (s *Server) expVarFunc(f func() interface{}) expvar.Func {
+func (s *Server) expVarFunc(f func() any) expvar.Func {
-	return expvar.Func(func() interface{} {
+	return expvar.Func(func() any {
 		s.mu.Lock()
 		defer s.mu.Unlock()
 		return f()
@@ -1652,14 +1652,14 @@ func (s *Server) expVarFunc(f func() interface{}) expvar.Func {
 // ExpVar returns an expvar variable suitable for registering with expvar.Publish.
 func (s *Server) ExpVar() expvar.Var {
 	m := new(metrics.Set)
-	m.Set("gauge_memstats_sys0", expvar.Func(func() interface{} { return int64(s.memSys0) }))
+	m.Set("gauge_memstats_sys0", expvar.Func(func() any { return int64(s.memSys0) }))
-	m.Set("gauge_watchers", s.expVarFunc(func() interface{} { return len(s.watchers) }))
+	m.Set("gauge_watchers", s.expVarFunc(func() any { return len(s.watchers) }))
-	m.Set("gauge_current_file_descriptors", expvar.Func(func() interface{} { return metrics.CurrentFDs() }))
+	m.Set("gauge_current_file_descriptors", expvar.Func(func() any { return metrics.CurrentFDs() }))
 	m.Set("gauge_current_connections", &s.curClients)
 	m.Set("gauge_current_home_connections", &s.curHomeClients)
-	m.Set("gauge_clients_total", expvar.Func(func() interface{} { return len(s.clientsMesh) }))
+	m.Set("gauge_clients_total", expvar.Func(func() any { return len(s.clientsMesh) }))
-	m.Set("gauge_clients_local", expvar.Func(func() interface{} { return len(s.clients) }))
+	m.Set("gauge_clients_local", expvar.Func(func() any { return len(s.clients) }))
-	m.Set("gauge_clients_remote", expvar.Func(func() interface{} { return len(s.clientsMesh) - len(s.clients) }))
+	m.Set("gauge_clients_remote", expvar.Func(func() any { return len(s.clientsMesh) - len(s.clients) }))
 	m.Set("gauge_current_dup_client_keys", &s.dupClientKeys)
 	m.Set("gauge_current_dup_client_conns", &s.dupClientConns)
 	m.Set("counter_total_dup_client_conns", &s.dupClientConnTotal)
@@ -1683,7 +1683,7 @@ func (s *Server) ExpVar() expvar.Var {
 	m.Set("multiforwarder_created", &s.multiForwarderCreated)
 	m.Set("multiforwarder_deleted", &s.multiForwarderDeleted)
 	m.Set("packet_forwarder_delete_other_value", &s.removePktForwardOther)
-	m.Set("average_queue_duration_ms", expvar.Func(func() interface{} {
+	m.Set("average_queue_duration_ms", expvar.Func(func() any {
 		return math.Float64frombits(atomic.LoadUint64(s.avgQueueDuration))
 	}))
 	var expvarVersion expvar.String
@@ -1813,7 +1813,7 @@ func (s *Server) ServeDebugTraffic(w http.ResponseWriter, r *http.Request) {
 }
 
 var bufioWriterPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return bufio.NewWriterSize(ioutil.Discard, 2<<10)
 	},
 }

derp/derp_test.go

@@ -802,7 +802,7 @@ func TestClientRecv(t *testing.T) {
 	tests := []struct {
 		name  string
 		input []byte
-		want  interface{}
+		want  any
 	}{
 		{
 			name: "ping",

envknob/envknob.go

@@ -46,7 +46,7 @@ func noteEnv(k, v string) {
 // logf is logger.Logf, but logger depends on envknob, so for circular
 // dependency reasons, make a type alias (so it's still assignable,
 // but has nice docs here).
-type logf = func(format string, args ...interface{})
+type logf = func(format string, args ...any)
 
 // LogCurrent logs the currently set environment knobs.
 func LogCurrent(logf logf) {

ipn/ipnlocal/peerapi.go

@@ -519,7 +519,7 @@ type peerAPIHandler struct {
 	peerUser   tailcfg.UserProfile // profile of peerNode
 }
 
-func (h *peerAPIHandler) logf(format string, a ...interface{}) {
+func (h *peerAPIHandler) logf(format string, a ...any) {
 	h.ps.b.logf("peerapi: "+format, a...)
 }
 

ipn/ipnlocal/ssh.go

@@ -83,7 +83,7 @@ func (b *LocalBackend) hostKeyFileOrCreate(keyDir, typ string) ([]byte, error) {
 	if !os.IsNotExist(err) {
 		return nil, err
 	}
-	var priv interface{}
+	var priv any
 	switch typ {
 	default:
 		return nil, fmt.Errorf("unsupported key type %q", typ)

ipn/ipnlocal/state_test.go

@@ -107,7 +107,7 @@ func newMockControl(tb testing.TB) *mockControl {
 	}
 }
 
-func (cc *mockControl) logf(format string, args ...interface{}) {
+func (cc *mockControl) logf(format string, args ...any) {
 	if cc.preventLog.Get() || cc.logfActual == nil {
 		return
 	}

ipn/ipnserver/server_test.go

@@ -28,7 +28,7 @@ func TestRunMultipleAccepts(t *testing.T) {
 	td := t.TempDir()
 	socketPath := filepath.Join(td, "tailscale.sock")
 
-	logf := func(format string, args ...interface{}) {
+	logf := func(format string, args ...any) {
 		format = strings.TrimRight(format, "\n")
 		println(fmt.Sprintf(format, args...))
 		t.Logf(format, args...)
@@ -52,7 +52,7 @@ func TestRunMultipleAccepts(t *testing.T) {
 		}
 	}
 
-	logTriggerTestf := func(format string, args ...interface{}) {
+	logTriggerTestf := func(format string, args ...any) {
 		logf(format, args...)
 		if strings.HasPrefix(format, "Listening on ") {
 			connect()

ipn/ipnstate/ipnstate.go

@@ -342,7 +342,7 @@ type StatusUpdater interface {
 }
 
 func (st *Status) WriteHTML(w io.Writer) {
-	f := func(format string, args ...interface{}) { fmt.Fprintf(w, format, args...) }
+	f := func(format string, args ...any) { fmt.Fprintf(w, format, args...) }
 
 	f(`<!DOCTYPE html>
 <html lang="en">

ipn/localapi/cert.go

@@ -85,7 +85,7 @@ func (h *Handler) serveCert(w http.ResponseWriter, r *http.Request) {
 
 	now := time.Now()
 	logf := logger.WithPrefix(h.logf, fmt.Sprintf("cert(%q): ", domain))
-	traceACME := func(v interface{}) {
+	traceACME := func(v any) {
 		if !acmeDebug {
 			return
 		}
@@ -164,7 +164,7 @@ func (h *Handler) getCertPEMCached(dir, domain string, now time.Time) (p *keyPai
 	return nil, false
 }
 
-func (h *Handler) getCertPEM(ctx context.Context, logf logger.Logf, traceACME func(interface{}), dir, domain string, now time.Time) (*keyPair, error) {
+func (h *Handler) getCertPEM(ctx context.Context, logf logger.Logf, traceACME func(any), dir, domain string, now time.Time) (*keyPair, error) {
 	acmeMu.Lock()
 	defer acmeMu.Unlock()
 

ipn/localapi/localapi.go

@@ -557,7 +557,7 @@ func defBool(a string, def bool) bool {
 // (currently only a slice or a map) and makes sure it's non-nil for
 // JSON serialization. (In particular, JavaScript clients usually want
 // the field to be defined after they decode the JSON.)
-func makeNonNil(ptr interface{}) {
+func makeNonNil(ptr any) {
 	if ptr == nil {
 		panic("nil interface")
 	}

ipn/message_test.go

@@ -85,10 +85,10 @@ func TestClientServer(t *testing.T) {
 	clientToServer := func(b []byte) {
 		bs.GotCommandMsg(context.TODO(), b)
 	}
-	slogf := func(fmt string, args ...interface{}) {
+	slogf := func(fmt string, args ...any) {
 		t.Logf("s: "+fmt, args...)
 	}
-	clogf := func(fmt string, args ...interface{}) {
+	clogf := func(fmt string, args ...any) {
 		t.Logf("c: "+fmt, args...)
 	}
 	bs = NewBackendServer(slogf, b, serverToClient)

ipn/prefs.go

@@ -42,7 +42,7 @@ var (
 
 // IsLoginServerSynonym reports whether a URL is a drop-in replacement
 // for the primary Tailscale login server.
-func IsLoginServerSynonym(val interface{}) bool {
+func IsLoginServerSynonym(val any) bool {
 	return val == "https://login.tailscale.com" || val == "https://controlplane.tailscale.com"
 }
 

kube/client.go

@@ -110,7 +110,7 @@ func getError(resp *http.Response) error {
 	return st
 }
 
-func (c *Client) doRequest(ctx context.Context, method, url string, in, out interface{}) error {
+func (c *Client) doRequest(ctx context.Context, method, url string, in, out any) error {
 	tk, err := c.getOrRenewToken()
 	if err != nil {
 		return err

log/filelogger/log.go

@@ -77,7 +77,7 @@ func dayOf(t time.Time) civilDay {
 	return civilDay{t.Year(), t.Month(), t.Day()}
 }
 
-func (w *logFileWriter) Logf(format string, a ...interface{}) {
+func (w *logFileWriter) Logf(format string, a ...any) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 

logpolicy/logpolicy.go

@@ -416,7 +416,7 @@ func New(collection string) *Policy {
 	console := log.New(stderrWriter{}, "", lflags)
 
 	var earlyErrBuf bytes.Buffer
-	earlyLogf := func(format string, a ...interface{}) {
+	earlyLogf := func(format string, a ...any) {
 		fmt.Fprintf(&earlyErrBuf, format, a...)
 		earlyErrBuf.WriteByte('\n')
 	}

logtail/logtail.go

@@ -515,7 +515,7 @@ func (l *Logger) encode(buf []byte, level int) []byte {
 
 	now := l.timeNow()
 
-	obj := make(map[string]interface{})
+	obj := make(map[string]any)
 	if err := json.Unmarshal(buf, &obj); err != nil {
 		for k := range obj {
 			delete(obj, k)
@@ -553,7 +553,7 @@ func (l *Logger) encode(buf []byte, level int) []byte {
 }
 
 // Logf logs to l using the provided fmt-style format and optional arguments.
-func (l *Logger) Logf(format string, args ...interface{}) {
+func (l *Logger) Logf(format string, args ...any) {
 	fmt.Fprintf(l, format, args...)
 }
 

logtail/logtail_test.go

@@ -128,7 +128,7 @@ func TestEncodeAndUploadMessages(t *testing.T) {
 
 		ltail, ok := data["logtail"]
 		if ok {
-			logtailmap := ltail.(map[string]interface{})
+			logtailmap := ltail.(map[string]any)
 			_, ok = logtailmap["client_time"]
 			if !ok {
 				t.Errorf("%s: no client_time present", tt.name)
@@ -317,9 +317,9 @@ func TestPublicIDUnmarshalText(t *testing.T) {
 	}
 }
 
-func unmarshalOne(t *testing.T, body []byte) map[string]interface{} {
+func unmarshalOne(t *testing.T, body []byte) map[string]any {
 	t.Helper()
-	var entries []map[string]interface{}
+	var entries []map[string]any
 	err := json.Unmarshal(body, &entries)
 	if err != nil {
 		t.Error(err)

net/dns/manager_linux_test.go

@@ -258,7 +258,7 @@ func TestLinuxDNSMode(t *testing.T) {
 	}
 }
 
-type memFS map[string]interface{} // full path => string for regular files
+type memFS map[string]any // full path => string for regular files
 
 func (m memFS) Stat(name string) (isRegular bool, err error) {
 	v, ok := m[name]

net/dns/nm.go

@@ -140,12 +140,12 @@ func (m *nmManager) trySet(ctx context.Context, config OSConfig) error {
 	// NetworkManager wipes out IPv6 address configuration unless we
 	// tell it explicitly to keep it. Read out the current interface
 	// settings and mirror them out to NetworkManager.
-	var addrs6 []map[string]interface{}
+	var addrs6 []map[string]any
 	addrs, _, err := interfaces.Tailscale()
 	if err == nil {
 		for _, a := range addrs {
 			if a.Is6() {
-				addrs6 = append(addrs6, map[string]interface{}{
+				addrs6 = append(addrs6, map[string]any{
 					"address": a.String(),
 					"prefix":  uint32(128),
 				})

net/dns/resolved.go

@@ -141,7 +141,7 @@ func (m *resolvedManager) resync(ctx context.Context, signals chan *dbus.Signal)
 			if signal.Path != dbusPath || signal.Name != dbusInterface+"."+dbusOwnerSignal {
 				continue
 			}
-			// signal.Body is a []interface{} of 3 strings: bus name, previous owner, new owner.
+			// signal.Body is a []any of 3 strings: bus name, previous owner, new owner.
 			if len(signal.Body) != 3 {
 				m.logf("[unexpectected] DBus NameOwnerChanged len(Body) = %d, want 3")
 			}

net/dns/resolver/tsdns.go

@@ -711,7 +711,7 @@ type response struct {
 }
 
 var dnsParserPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new(dnsParser)
 	},
 }

net/dns/resolver/tsdns_server_test.go

@@ -221,7 +221,7 @@ func weirdoGoCNAMEHandler(target string) dns.HandlerFunc {
 // provided.
 //
 // Types supported: netaddr.IP.
-func dnsHandler(answers ...interface{}) dns.HandlerFunc {
+func dnsHandler(answers ...any) dns.HandlerFunc {
 	return func(w dns.ResponseWriter, req *dns.Msg) {
 		m := new(dns.Msg)
 		m.SetReply(req)
@@ -303,7 +303,7 @@ func dnsHandler(answers ...interface{}) dns.HandlerFunc {
 	}
 }
 
-func serveDNS(tb testing.TB, addr string, records ...interface{}) *dns.Server {
+func serveDNS(tb testing.TB, addr string, records ...any) *dns.Server {
 	if len(records)%2 != 0 {
 		panic("must have an even number of record values")
 	}

net/dns/resolver/tsdns_test.go

@@ -454,7 +454,7 @@ func TestDelegate(t *testing.T) {
 	// intend to handle responses this large, so there should be truncation.
 	hugeTXT := generateTXT(64000, randSource)
 
-	records := []interface{}{
+	records := []any{
 		"test.site.",
 		resolveToIP(testipv4, testipv6, "dns.test.site."),
 		"LCtesT.SiTe.",
@@ -1105,7 +1105,7 @@ func TestHandleExitNodeDNSQueryWithNetPkg(t *testing.T) {
 		t.Skip("skipping test on Windows; waiting for golang.org/issue/33097")
 	}
 
-	records := []interface{}{
+	records := []any{
 		"no-records.test.",
 		dnsHandler(),
 

net/dnscache/dnscache.go

@@ -129,7 +129,7 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 net.IP, al
 		ip, ip6 net.IP
 		allIPs  []net.IPAddr
 	}
-	ch := r.sf.DoChan(host, func() (interface{}, error) {
+	ch := r.sf.DoChan(host, func() (any, error) {
 		ip, ip6, allIPs, err := r.lookupIP(host)
 		if err != nil {
 			return nil, err

net/dnscache/messagecache.go

@@ -103,7 +103,7 @@ type msgResource struct {
 var ErrCacheMiss = errors.New("cache miss")
 
 var parserPool = &sync.Pool{
-	New: func() interface{} { return new(dnsmessage.Parser) },
+	New: func() any { return new(dnsmessage.Parser) },
 }
 
 // ReplyFromCache writes a DNS reply to w for the provided DNS query message,

net/dnscache/messagecache_test.go

@@ -118,17 +118,17 @@ type responseOpt bool
 
 type ttlOpt uint32
 
-func makeQ(txID uint16, name string, opt ...interface{}) []byte {
+func makeQ(txID uint16, name string, opt ...any) []byte {
 	opt = append(opt, responseOpt(false))
 	return makeDNSPkt(txID, name, opt...)
 }
 
-func makeRes(txID uint16, name string, opt ...interface{}) []byte {
+func makeRes(txID uint16, name string, opt ...any) []byte {
 	opt = append(opt, responseOpt(true))
 	return makeDNSPkt(txID, name, opt...)
 }
 
-func makeDNSPkt(txID uint16, name string, opt ...interface{}) []byte {
+func makeDNSPkt(txID uint16, name string, opt ...any) []byte {
 	typ := dnsmessage.TypeA
 	class := dnsmessage.ClassINET
 	var response bool

net/flowtrack/flowtrack.go

@@ -46,7 +46,7 @@ type Cache struct {
 // entry is the container/list element type.
 type entry struct {
 	key   Tuple
-	value interface{}
+	value any
 }
 
 // Add adds a value to the cache, set or updating its associated
@@ -54,7 +54,7 @@ type entry struct {
 //
 // If MaxEntries is non-zero and the length of the cache is greater
 // after any addition, the least recently used value is evicted.
-func (c *Cache) Add(key Tuple, value interface{}) {
+func (c *Cache) Add(key Tuple, value any) {
 	if c.m == nil {
 		c.m = make(map[Tuple]*list.Element)
 		c.ll = list.New()
@@ -73,7 +73,7 @@ func (c *Cache) Add(key Tuple, value interface{}) {
 
 // Get looks up a key's value from the cache, also reporting
 // whether it was present.
-func (c *Cache) Get(key Tuple) (value interface{}, ok bool) {
+func (c *Cache) Get(key Tuple) (value any, ok bool) {
 	if ele, hit := c.m[key]; hit {
 		c.ll.MoveToFront(ele)
 		return ele.Value.(*entry).value, true

net/flowtrack/flowtrack_test.go

@@ -25,7 +25,7 @@ func TestCache(t *testing.T) {
 			t.Fatalf("Len = %d; want %d", got, want)
 		}
 	}
-	wantVal := func(key Tuple, want interface{}) {
+	wantVal := func(key Tuple, want any) {
 		t.Helper()
 		got, ok := c.Get(key)
 		if !ok {

net/netcheck/netcheck.go

@@ -191,7 +191,7 @@ func (c *Client) enoughRegions() int {
 	return 3
 }
 
-func (c *Client) logf(format string, a ...interface{}) {
+func (c *Client) logf(format string, a ...any) {
 	if c.Logf != nil {
 		c.Logf(format, a...)
 	} else {
@@ -199,7 +199,7 @@ func (c *Client) logf(format string, a ...interface{}) {
 	}
 }
 
-func (c *Client) vlogf(format string, a ...interface{}) {
+func (c *Client) vlogf(format string, a ...any) {
 	if c.Verbose || debugNetcheck {
 		c.logf(format, a...)
 	}

net/netcheck/netcheck_test.go

@@ -119,7 +119,7 @@ func TestWorksWhenUDPBlocked(t *testing.T) {
 
 func TestAddReportHistoryAndSetPreferredDERP(t *testing.T) {
 	// report returns a *Report from (DERP host, time.Duration)+ pairs.
-	report := func(a ...interface{}) *Report {
+	report := func(a ...any) *Report {
 		r := &Report{RegionLatency: map[int]time.Duration{}}
 		for i := 0; i < len(a); i += 2 {
 			s := a[i].(string)
@@ -606,7 +606,7 @@ func TestLogConciseReport(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			var buf bytes.Buffer
-			c := &Client{Logf: func(f string, a ...interface{}) { fmt.Fprintf(&buf, f, a...) }}
+			c := &Client{Logf: func(f string, a ...any) { fmt.Fprintf(&buf, f, a...) }}
 			c.logConciseReport(tt.r, dm)
 			if got := strings.TrimPrefix(buf.String(), "[v1] report: "); got != tt.want {
 				t.Errorf("unexpected result.\n got: %#q\nwant: %#q\n", got, tt.want)

net/portmapper/disabled_stubs.go

@@ -15,7 +15,7 @@ import (
 	"inet.af/netaddr"
 )
 
-type upnpClient interface{}
+type upnpClient any
 
 type uPnPDiscoResponse struct{}
 

net/portmapper/igd_test.go

@@ -67,7 +67,7 @@ func NewTestIGD(logf logger.Logf, t TestIGDOptions) (*TestIGD, error) {
 		doPCP:  t.PCP,
 		doUPnP: t.UPnP,
 	}
-	d.logf = func(msg string, args ...interface{}) {
+	d.logf = func(msg string, args ...any) {
 		// Don't log after the device has closed;
 		// stray trailing logging angers testing.T.Logf.
 		if d.closed.Get() {

net/socks5/socks5.go

@@ -95,7 +95,7 @@ func (s *Server) dial(ctx context.Context, network, addr string) (net.Conn, erro
 	return dial(ctx, network, addr)
 }
 
-func (s *Server) logf(format string, args ...interface{}) {
+func (s *Server) logf(format string, args ...any) {
 	logf := s.Logf
 	if logf == nil {
 		logf = log.Printf

net/tstun/wrap.go

@@ -60,7 +60,7 @@ var (
 // parsedPacketPool holds a pool of Parsed structs for use in filtering.
 // This is needed because escape analysis cannot see that parsed packets
 // do not escape through {Pre,Post}Filter{In,Out}.
-var parsedPacketPool = sync.Pool{New: func() interface{} { return new(packet.Parsed) }}
+var parsedPacketPool = sync.Pool{New: func() any { return new(packet.Parsed) }}
 
 // FilterFunc is a packet-filtering function with access to the Wrapper device.
 // It must not hold onto the packet struct, as its backing storage will be reused.

packages/deb/deb_test.go

@@ -141,7 +141,7 @@ func TestDebInfo(t *testing.T) {
 	}
 }
 
-func diff(got, want interface{}) string {
+func diff(got, want any) string {
 	matchField := func(name string) func(p cmp.Path) bool {
 		return func(p cmp.Path) bool {
 			if len(p) != 3 {

ssh/tailssh/context.go

@@ -42,7 +42,7 @@ func (ctx *sshContext) Err() error {
 
 func (ctx *sshContext) Done() <-chan struct{}                   { return ctx.done }
 func (ctx *sshContext) Deadline() (deadline time.Time, ok bool) { return }
-func (ctx *sshContext) Value(interface{}) interface{}           { return nil }
+func (ctx *sshContext) Value(any) any                           { return nil }
 
 // userVisibleError is a wrapper around an error that implements
 // SSHTerminationError, so msg is written to their session.

ssh/tailssh/incubator_linux.go

@@ -35,7 +35,7 @@ func ptyNameLinux(f *os.File) (string, error) {
 
 // callLogin1 invokes the provided method of the "login1" service over D-Bus.
 // https://www.freedesktop.org/software/systemd/man/org.freedesktop.login1.html
-func callLogin1(method string, flags dbus.Flags, args ...interface{}) (*dbus.Call, error) {
+func callLogin1(method string, flags dbus.Flags, args ...any) (*dbus.Call, error) {
 	conn, err := dbus.SystemBus()
 	if err != nil {
 		// DBus probably not running.
@@ -77,8 +77,8 @@ type createSessionArgs struct {
 	}
 }
 
-func (a createSessionArgs) args() []interface{} {
+func (a createSessionArgs) args() []any {
-	return []interface{}{
+	return []any{
 		a.uid,
 		a.pid,
 		a.service,

tailcfg/tailcfg_clone.go

@@ -326,7 +326,7 @@ var _DERPNodeCloneNeedsRegeneration = DERPNode(struct {
 // Clone duplicates src into dst and reports whether it succeeded.
 // To succeed, <src, dst> must be of types <*T, *T> or <*T, **T>,
 // where T is one of User,Node,Hostinfo,NetInfo,Login,DNSConfig,RegisterResponse,DERPRegion,DERPMap,DERPNode.
-func Clone(dst, src interface{}) bool {
+func Clone(dst, src any) bool {
 	switch src := src.(type) {
 	case *User:
 		switch dst := dst.(type) {

tstest/integration/testcontrol/testcontrol.go

@@ -189,7 +189,7 @@ func (ap *AuthPath) CompleteSuccessfully() {
 	ap.closeOnce.Do(ap.completeSuccessfully)
 }
 
-func (s *Server) logf(format string, a ...interface{}) {
+func (s *Server) logf(format string, a ...any) {
 	if s.Logf != nil {
 		s.Logf(format, a...)
 	} else {
@@ -779,7 +779,7 @@ func (s *Server) MapResponse(req *tailcfg.MapRequest) (res *tailcfg.MapResponse,
 	return res, nil
 }
 
-func (s *Server) sendMapMsg(w http.ResponseWriter, mkey key.MachinePublic, compress bool, msg interface{}) error {
+func (s *Server) sendMapMsg(w http.ResponseWriter, mkey key.MachinePublic, compress bool, msg any) error {
 	resBytes, err := s.encode(mkey, compress, msg)
 	if err != nil {
 		return err
@@ -803,7 +803,7 @@ func (s *Server) sendMapMsg(w http.ResponseWriter, mkey key.MachinePublic, compr
 	return nil
 }
 
-func (s *Server) decode(mkey key.MachinePublic, msg []byte, v interface{}) error {
+func (s *Server) decode(mkey key.MachinePublic, msg []byte, v any) error {
 	if len(msg) == msgLimit {
 		return errors.New("encrypted message too long")
 	}
@@ -816,7 +816,7 @@ func (s *Server) decode(mkey key.MachinePublic, msg []byte, v interface{}) error
 }
 
 var zstdEncoderPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		encoder, err := smallzstd.NewEncoder(nil, zstd.WithEncoderLevel(zstd.SpeedFastest))
 		if err != nil {
 			panic(err)
@@ -825,7 +825,7 @@ var zstdEncoderPool = &sync.Pool{
 	},
 }
 
-func (s *Server) encode(mkey key.MachinePublic, compress bool, v interface{}) (b []byte, err error) {
+func (s *Server) encode(mkey key.MachinePublic, compress bool, v any) (b []byte, err error) {
 	var isBytes bool
 	if b, isBytes = v.([]byte); !isBytes {
 		b, err = json.Marshal(v)

tstest/log.go

@@ -82,7 +82,7 @@ type LogLineTracker struct {
 }
 
 // Logf logs to its underlying logger and also tracks that the given format pattern has been seen.
-func (lt *LogLineTracker) Logf(format string, args ...interface{}) {
+func (lt *LogLineTracker) Logf(format string, args ...any) {
 	lt.mu.Lock()
 	if lt.closed {
 		lt.mu.Unlock()
@@ -131,7 +131,7 @@ type MemLogger struct {
 	bytes.Buffer
 }
 
-func (ml *MemLogger) Logf(format string, args ...interface{}) {
+func (ml *MemLogger) Logf(format string, args ...any) {
 	ml.Lock()
 	defer ml.Unlock()
 	fmt.Fprintf(&ml.Buffer, format, args...)

tstest/natlab/natlab.go

@@ -66,16 +66,16 @@ func (p *Packet) short() string {
 	return fmt.Sprintf("%s/%s", payload, tuple)
 }
 
-func (p *Packet) Trace(msg string, args ...interface{}) {
+func (p *Packet) Trace(msg string, args ...any) {
 	if !traceOn {
 		return
 	}
-	allArgs := []interface{}{p.short(), p.locator, p.Src, p.Dst}
+	allArgs := []any{p.short(), p.locator, p.Src, p.Dst}
 	allArgs = append(allArgs, args...)
 	fmt.Fprintf(os.Stderr, "[%s]%s src=%s dst=%s "+msg+"\n", allArgs...)
 }
 
-func (p *Packet) setLocator(msg string, args ...interface{}) {
+func (p *Packet) setLocator(msg string, args ...any) {
 	p.locator = fmt.Sprintf(" "+msg, args...)
 }
 

tsweb/debug.go

@@ -52,7 +52,7 @@ func Debugger(mux *http.ServeMux) *DebugHandler {
 	// index page. The /pprof/ index already covers it.
 	mux.Handle("/debug/pprof/profile", http.HandlerFunc(pprof.Profile))
 
-	ret.KVFunc("Uptime", func() interface{} { return Uptime() })
+	ret.KVFunc("Uptime", func() any { return Uptime() })
 	ret.KV("Version", version.Long)
 	ret.Handle("vars", "Metrics (Go)", expvar.Handler())
 	ret.Handle("varz", "Metrics (Prometheus)", http.HandlerFunc(VarzHandler))
@@ -79,7 +79,7 @@ func (d *DebugHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	f := func(format string, args ...interface{}) { fmt.Fprintf(w, format, args...) }
+	f := func(format string, args ...any) { fmt.Fprintf(w, format, args...) }
 	f("<html><body><h1>%s debug</h1><ul>", version.CmdName())
 	for _, kv := range d.kvs {
 		kv(w)
@@ -101,7 +101,7 @@ func (d *DebugHandler) Handle(slug, desc string, handler http.Handler) {
 }
 
 // KV adds a key/value list item to /debug/.
-func (d *DebugHandler) KV(k string, v interface{}) {
+func (d *DebugHandler) KV(k string, v any) {
 	val := html.EscapeString(fmt.Sprintf("%v", v))
 	d.kvs = append(d.kvs, func(w io.Writer) {
 		fmt.Fprintf(w, "<li><b>%s:</b> %s</li>", k, val)
@@ -110,7 +110,7 @@ func (d *DebugHandler) KV(k string, v interface{}) {
 
 // KVFunc adds a key/value list item to /debug/. v is called on every
 // render of /debug/.
-func (d *DebugHandler) KVFunc(k string, v func() interface{}) {
+func (d *DebugHandler) KVFunc(k string, v func() any) {
 	d.kvs = append(d.kvs, func(w io.Writer) {
 		val := html.EscapeString(fmt.Sprintf("%v", v()))
 		fmt.Fprintf(w, "<li><b>%s:</b> %s</li>", k, val)

tsweb/debug_test.go

@@ -66,7 +66,7 @@ func TestDebuggerKV(t *testing.T) {
 	dbg.KV("Donuts", 42)
 	dbg.KV("Secret code", "hunter2")
 	val := "red"
-	dbg.KVFunc("Condition", func() interface{} { return val })
+	dbg.KVFunc("Condition", func() any { return val })
 
 	code, _ := get(mux, "/debug/", pubIP)
 	if code != 403 {
@@ -183,7 +183,7 @@ func ExampleDebugHandler_KVFunc() {
 	// Adds an count of page renders to /debug/. Note this example
 	// isn't concurrency-safe.
 	views := 0
-	dbg.KVFunc("Debug pageviews", func() interface{} {
+	dbg.KVFunc("Debug pageviews", func() any {
 		views = views + 1
 		return views
 	})

tsweb/jsonhandler.go

@@ -19,16 +19,16 @@ import (
 )
 
 type response struct {
-	Status string      `json:"status"`
+	Status string `json:"status"`
-	Error  string      `json:"error,omitempty"`
+	Error  string `json:"error,omitempty"`
-	Data   interface{} `json:"data,omitempty"`
+	Data   any    `json:"data,omitempty"`
 }
 
 // JSONHandlerFunc is an HTTP ReturnHandler that writes JSON responses to the client.
 //
 // Return a HTTPError to show an error message, otherwise JSONHandlerFunc will
 // only report "internal server error" to the user with status code 500.
-type JSONHandlerFunc func(r *http.Request) (status int, data interface{}, err error)
+type JSONHandlerFunc func(r *http.Request) (status int, data any, err error)
 
 // ServeHTTPReturn implements the ReturnHandler interface.
 //

tsweb/jsonhandler_test.go

@@ -71,7 +71,7 @@ func TestNewJSONHandler(t *testing.T) {
 		return d
 	}
 
-	h21 := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+	h21 := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 		return http.StatusOK, nil, nil
 	})
 
@@ -83,7 +83,7 @@ func TestNewJSONHandler(t *testing.T) {
 	})
 
 	t.Run("403 HTTPError", func(t *testing.T) {
-		h := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+		h := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 			return 0, nil, Error(http.StatusForbidden, "forbidden", nil)
 		})
 
@@ -93,7 +93,7 @@ func TestNewJSONHandler(t *testing.T) {
 		checkStatus(t, w, "error", http.StatusForbidden)
 	})
 
-	h22 := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+	h22 := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 		return http.StatusOK, &Data{Name: "tailscale"}, nil
 	})
 
@@ -104,7 +104,7 @@ func TestNewJSONHandler(t *testing.T) {
 		checkStatus(t, w, "success", http.StatusOK)
 	})
 
-	h31 := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+	h31 := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 		body := new(Data)
 		if err := json.NewDecoder(r.Body).Decode(body); err != nil {
 			return 0, nil, Error(http.StatusBadRequest, err.Error(), err)
@@ -140,7 +140,7 @@ func TestNewJSONHandler(t *testing.T) {
 		}
 	})
 
-	h32 := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+	h32 := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 		body := new(Data)
 		if err := json.NewDecoder(r.Body).Decode(body); err != nil {
 			return 0, nil, Error(http.StatusBadRequest, err.Error(), err)
@@ -187,7 +187,7 @@ func TestNewJSONHandler(t *testing.T) {
 		r := httptest.NewRequest("POST", "/", strings.NewReader(`{"Price": 10}`))
 		r.Header.Set("Accept-Encoding", "gzip")
 		value := []string{"foo", "foo", "foo"}
-		JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+		JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 			return 400, value, nil
 		}).ServeHTTPReturn(w, r)
 		res := w.Result()
@@ -222,7 +222,7 @@ func TestNewJSONHandler(t *testing.T) {
 	t.Run("500 misuse", func(t *testing.T) {
 		w := httptest.NewRecorder()
 		r := httptest.NewRequest("POST", "/", nil)
-		JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+		JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 			return http.StatusOK, make(chan int), nil
 		}).ServeHTTPReturn(w, r)
 		resp := checkStatus(t, w, "error", http.StatusInternalServerError)
@@ -234,7 +234,7 @@ func TestNewJSONHandler(t *testing.T) {
 	t.Run("500 empty status code", func(t *testing.T) {
 		w := httptest.NewRecorder()
 		r := httptest.NewRequest("POST", "/", nil)
-		JSONHandlerFunc(func(r *http.Request) (status int, data interface{}, err error) {
+		JSONHandlerFunc(func(r *http.Request) (status int, data any, err error) {
 			return
 		}).ServeHTTPReturn(w, r)
 		checkStatus(t, w, "error", http.StatusInternalServerError)
@@ -243,7 +243,7 @@ func TestNewJSONHandler(t *testing.T) {
 	t.Run("403 forbidden, status returned by JSONHandlerFunc and HTTPError agree", func(t *testing.T) {
 		w := httptest.NewRecorder()
 		r := httptest.NewRequest("POST", "/", nil)
-		JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+		JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 			return http.StatusForbidden, nil, Error(http.StatusForbidden, "403 forbidden", nil)
 		}).ServeHTTPReturn(w, r)
 		want := &Response{
@@ -260,7 +260,7 @@ func TestNewJSONHandler(t *testing.T) {
 	t.Run("403 forbidden, status returned by JSONHandlerFunc and HTTPError do not agree", func(t *testing.T) {
 		w := httptest.NewRecorder()
 		r := httptest.NewRequest("POST", "/", nil)
-		err := JSONHandlerFunc(func(r *http.Request) (int, interface{}, error) {
+		err := JSONHandlerFunc(func(r *http.Request) (int, any, error) {
 			return http.StatusInternalServerError, nil, Error(http.StatusForbidden, "403 forbidden", nil)
 		}).ServeHTTPReturn(w, r)
 		if !strings.HasPrefix(err.Error(), "[unexpected]") {

tsweb/tsweb.go

@@ -33,10 +33,10 @@ import (
 )
 
 func init() {
-	expvar.Publish("process_start_unix_time", expvar.Func(func() interface{} { return timeStart.Unix() }))
+	expvar.Publish("process_start_unix_time", expvar.Func(func() any { return timeStart.Unix() }))
-	expvar.Publish("version", expvar.Func(func() interface{} { return version.Long }))
+	expvar.Publish("version", expvar.Func(func() any { return version.Long }))
-	expvar.Publish("counter_uptime_sec", expvar.Func(func() interface{} { return int64(Uptime().Seconds()) }))
+	expvar.Publish("counter_uptime_sec", expvar.Func(func() any { return int64(Uptime().Seconds()) }))
-	expvar.Publish("gauge_goroutines", expvar.Func(func() interface{} { return runtime.NumGoroutine() }))
+	expvar.Publish("gauge_goroutines", expvar.Func(func() any { return runtime.NumGoroutine() }))
 }
 
 // DevMode controls whether extra output in shown, for when the binary is being run in dev mode.
@@ -513,7 +513,7 @@ type PrometheusMetricsReflectRooter interface {
 	expvar.Var
 
 	// PrometheusMetricsReflectRoot returns the struct or struct pointer to walk.
-	PrometheusMetricsReflectRoot() interface{}
+	PrometheusMetricsReflectRoot() any
 }
 
 var expvarDo = expvar.Do // pulled out for tests
@@ -562,10 +562,10 @@ func foreachExportedStructField(rv reflect.Value, f func(fieldOrJSONName, metric
 	}
 }
 
-type expVarPromStructRoot struct{ v interface{} }
+type expVarPromStructRoot struct{ v any }
 
-func (r expVarPromStructRoot) PrometheusMetricsReflectRoot() interface{} { return r.v }
+func (r expVarPromStructRoot) PrometheusMetricsReflectRoot() any { return r.v }
-func (r expVarPromStructRoot) String() string                            { panic("unused") }
+func (r expVarPromStructRoot) String() string                    { panic("unused") }
 
 var (
 	_ PrometheusMetricsReflectRooter = expVarPromStructRoot{}

tsweb/tsweb_test.go

@@ -241,7 +241,7 @@ func TestStdHandler(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			var logs []AccessLogRecord
-			logf := func(fmt string, args ...interface{}) {
+			logf := func(fmt string, args ...any) {
 				if fmt == "%s" {
 					logs = append(logs, args[0].(AccessLogRecord))
 				}
@@ -378,19 +378,19 @@ func TestVarzHandler(t *testing.T) {
 		{
 			"func_float64",
 			"counter_x",
-			expvar.Func(func() interface{} { return float64(1.2) }),
+			expvar.Func(func() any { return float64(1.2) }),
 			"# TYPE x counter\nx 1.2\n",
 		},
 		{
 			"func_float64_gauge",
 			"gauge_x",
-			expvar.Func(func() interface{} { return float64(1.2) }),
+			expvar.Func(func() any { return float64(1.2) }),
 			"# TYPE x gauge\nx 1.2\n",
 		},
 		{
 			"func_float64_untyped",
 			"x",
-			expvar.Func(func() interface{} { return float64(1.2) }),
+			expvar.Func(func() any { return float64(1.2) }),
 			"x 1.2\n",
 		},
 		{
@@ -466,7 +466,7 @@ foo_AUint16 65535
 		{
 			"func_returning_int",
 			"num_goroutines",
-			expvar.Func(func() interface{} { return 123 }),
+			expvar.Func(func() any { return 123 }),
 			"num_goroutines 123\n",
 		},
 	}
@@ -531,6 +531,6 @@ type expvarAdapter struct {
 
 func (expvarAdapter) String() string { return "{}" } // expvar JSON; unused in test
 
-func (a expvarAdapter) PrometheusMetricsReflectRoot() interface{} {
+func (a expvarAdapter) PrometheusMetricsReflectRoot() any {
 	return a.st
 }

types/dnstype/dnstype_clone.go

@@ -32,7 +32,7 @@ var _ResolverCloneNeedsRegeneration = Resolver(struct {
 // Clone duplicates src into dst and reports whether it succeeded.
 // To succeed, <src, dst> must be of types <*T, *T> or <*T, **T>,
 // where T is one of Resolver.
-func Clone(dst, src interface{}) bool {
+func Clone(dst, src any) bool {
 	switch src := src.(type) {
 	case *Resolver:
 		switch dst := dst.(type) {

types/logger/logger.go

@@ -28,7 +28,7 @@ import (
 // Logf is the basic Tailscale logger type: a printf-like func.
 // Like log.Printf, the format need not end in a newline.
 // Logf functions must be safe for concurrent use.
-type Logf func(format string, args ...interface{})
+type Logf func(format string, args ...any)
 
 // A Context is a context.Context that should contain a custom log function, obtainable from FromContext.
 // If no log function is present, FromContext will return log.Printf.
@@ -43,7 +43,7 @@ type jenc struct {
 	enc *json.Encoder
 }
 
-var jencPool = &sync.Pool{New: func() interface{} {
+var jencPool = &sync.Pool{New: func() any {
 	je := new(jenc)
 	je.enc = json.NewEncoder(&je.buf)
 	return je
@@ -61,7 +61,7 @@ var jencPool = &sync.Pool{New: func() interface{} {
 //
 // The level can be from 0 to 9. Levels from 1 to 9 are included in
 // the logged JSON object, like {"foo":123,"v":2}.
-func (logf Logf) JSON(level int, recType string, v interface{}) {
+func (logf Logf) JSON(level int, recType string, v any) {
 	je := jencPool.Get().(*jenc)
 	defer jencPool.Put(je)
 	je.buf.Reset()
@@ -96,7 +96,7 @@ func Ctx(ctx context.Context, fn Logf) Context {
 
 // WithPrefix wraps f, prefixing each format with the provided prefix.
 func WithPrefix(f Logf, prefix string) Logf {
-	return func(format string, args ...interface{}) {
+	return func(format string, args ...any) {
 		f(prefix+format, args...)
 	}
 }
@@ -119,7 +119,7 @@ func (w funcWriter) Write(p []byte) (int, error) {
 }
 
 // Discard is a Logf that throws away the logs given to it.
-func Discard(string, ...interface{}) {}
+func Discard(string, ...any) {}
 
 // limitData is used to keep track of each format string's associated
 // rate-limiting data.
@@ -165,7 +165,7 @@ func RateLimitedFnWithClock(logf Logf, f time.Duration, burst int, maxCache int,
 		msgCache = list.New()                  // a rudimentary LRU that limits the size of the map
 	)
 
-	return func(format string, args ...interface{}) {
+	return func(format string, args ...any) {
 		// Shortcut for formats with no rate limit
 		for _, sub := range rateFree {
 			if strings.Contains(format, sub) {
@@ -239,7 +239,7 @@ func LogOnChange(logf Logf, maxInterval time.Duration, timeNow func() time.Time)
 		tLastLogged = timeNow()
 	)
 
-	return func(format string, args ...interface{}) {
+	return func(format string, args ...any) {
 		s := fmt.Sprintf(format, args...)
 
 		mu.Lock()
@@ -270,13 +270,13 @@ func (fn ArgWriter) Format(f fmt.State, _ rune) {
 	argBufioPool.Put(bw)
 }
 
-var argBufioPool = &sync.Pool{New: func() interface{} { return bufio.NewWriterSize(ioutil.Discard, 1024) }}
+var argBufioPool = &sync.Pool{New: func() any { return bufio.NewWriterSize(ioutil.Discard, 1024) }}
 
 // Filtered returns a Logf that silently swallows some log lines.
 // Each inbound format and args is evaluated and printed to a string s.
 // The original format and args are passed to logf if and only if allow(s) returns true.
 func Filtered(logf Logf, allow func(s string) bool) Logf {
-	return func(format string, args ...interface{}) {
+	return func(format string, args ...any) {
 		msg := fmt.Sprintf(format, args...)
 		if !allow(msg) {
 			return
@@ -297,7 +297,7 @@ func LogfCloser(logf Logf) (newLogf Logf, close func()) {
 		defer mu.Unlock()
 		closed = true
 	}
-	newLogf = func(msg string, args ...interface{}) {
+	newLogf = func(msg string, args ...any) {
 		mu.Lock()
 		if closed {
 			mu.Unlock()

types/logger/logger_test.go

@@ -30,7 +30,7 @@ func TestStdLogger(t *testing.T) {
 }
 
 func logTester(want []string, t *testing.T, i *int) Logf {
-	return func(format string, args ...interface{}) {
+	return func(format string, args ...any) {
 		got := fmt.Sprintf(format, args...)
 		if *i >= len(want) {
 			t.Fatalf("Logging continued past end of expected input: %s", got)
@@ -204,7 +204,7 @@ func TestContext(t *testing.T) {
 
 	// Test that FromContext and Ctx work together.
 	var called bool
-	markCalled := func(string, ...interface{}) {
+	markCalled := func(string, ...any) {
 		called = true
 	}
 	ctx = Ctx(ctx, markCalled)
@@ -215,7 +215,7 @@ func TestContext(t *testing.T) {
 
 func TestJSON(t *testing.T) {
 	var buf bytes.Buffer
-	var logf Logf = func(f string, a ...interface{}) { fmt.Fprintf(&buf, f, a...) }
+	var logf Logf = func(f string, a ...any) { fmt.Fprintf(&buf, f, a...) }
 	logf.JSON(1, "foo", &tailcfg.Hostinfo{})
 	want := "[v\x00JSON]1" + `{"foo":{"OS":"","Hostname":""}}`
 	if got := buf.String(); got != want {

types/logger/rusage.go

@@ -13,7 +13,7 @@ import (
 // a prefixed log message to each line with the current binary memory usage
 // and max RSS.
 func RusagePrefixLog(logf Logf) Logf {
-	return func(f string, argv ...interface{}) {
+	return func(f string, argv ...any) {
 		var m runtime.MemStats
 		runtime.ReadMemStats(&m)
 		goMem := float64(m.HeapInuse+m.StackInuse) / (1 << 20)

types/opt/bool.go

@@ -30,7 +30,7 @@ func (b Bool) Get() (v bool, ok bool) {
 }
 
 // Scan implements database/sql.Scanner.
-func (b *Bool) Scan(src interface{}) error {
+func (b *Bool) Scan(src any) error {
 	if src == nil {
 		*b = ""
 		return nil

types/opt/bool_test.go

@@ -13,7 +13,7 @@ import (
 func TestBool(t *testing.T) {
 	tests := []struct {
 		name string
-		in   interface{}
+		in   any
 		want string // JSON
 	}{
 		{

util/clientmetric/clientmetric.go

@@ -256,7 +256,7 @@ func EncodeLogTailMetricsDelta() string {
 }
 
 var deltaPool = &sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new(deltaEncBuf)
 	},
 }

util/codegen/codegen.go

@@ -79,7 +79,7 @@ func NamedTypes(pkg *packages.Package) map[string]*types.Named {
 // for each package path that the caller must import for the returned code to compile.
 func AssertStructUnchanged(t *types.Struct, thisPkg *types.Package, tname, ctx string, imports map[string]struct{}) []byte {
 	buf := new(bytes.Buffer)
-	w := func(format string, args ...interface{}) {
+	w := func(format string, args ...any) {
 		fmt.Fprintf(buf, format+"\n", args...)
 	}
 	w("// A compilation failure here means this code must be regenerated, with the command at the top of this file.")

util/deephash/deephash.go

@@ -113,11 +113,11 @@ func (h *hasher) sum() (s Sum) {
 }
 
 var hasherPool = &sync.Pool{
-	New: func() interface{} { return new(hasher) },
+	New: func() any { return new(hasher) },
 }
 
 // Hash returns the hash of v.
-func Hash(v interface{}) (s Sum) {
+func Hash(v any) (s Sum) {
 	h := hasherPool.Get().(*hasher)
 	defer hasherPool.Put(h)
 	h.reset()
@@ -130,7 +130,7 @@ func Hash(v interface{}) (s Sum) {
 }
 
 // Update sets last to the hash of v and reports whether its value changed.
-func Update(last *Sum, v ...interface{}) (changed bool) {
+func Update(last *Sum, v ...any) (changed bool) {
 	sum := Hash(v)
 	if sum == *last {
 		// unchanged.
@@ -304,7 +304,7 @@ type mapHasher struct {
 }
 
 var mapHasherPool = &sync.Pool{
-	New: func() interface{} { return new(mapHasher) },
+	New: func() any { return new(mapHasher) },
 }
 
 type valueCache map[reflect.Type]reflect.Value

util/deephash/deephash_test.go

@@ -35,8 +35,8 @@ func (p appendBytes) AppendTo(b []byte) []byte {
 }
 
 func TestHash(t *testing.T) {
-	type tuple [2]interface{}
+	type tuple [2]any
-	type iface struct{ X interface{} }
+	type iface struct{ X any }
 	type scalars struct {
 		I8   int8
 		I16  int16
@@ -132,8 +132,8 @@ func TestDeepHash(t *testing.T) {
 	}
 }
 
-func getVal() []interface{} {
+func getVal() []any {
-	return []interface{}{
+	return []any{
 		&wgcfg.Config{
 			Name:      "foo",
 			Addresses: []netaddr.IPPrefix{netaddr.IPPrefixFrom(netaddr.IPFrom16([16]byte{3: 3}), 5)},
@@ -321,10 +321,10 @@ func TestExhaustive(t *testing.T) {
 // verify this doesn't loop forever, as it used to (Issue 2340)
 func TestMapCyclicFallback(t *testing.T) {
 	type T struct {
-		M map[string]interface{}
+		M map[string]any
 	}
 	v := &T{
-		M: map[string]interface{}{},
+		M: map[string]any{},
 	}
 	v.M["m"] = v.M
 	Hash(v)

util/jsonutil/unmarshal.go

@@ -20,13 +20,13 @@ type decoder struct {
 }
 
 var readerPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return bytes.NewReader(nil)
 	},
 }
 
 var decoderPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		var d decoder
 		d.r = readerPool.Get().(*bytes.Reader)
 		d.dec = json.NewDecoder(d.r)
@@ -47,7 +47,7 @@ var decoderPool = sync.Pool{
 // don't use this Unmarshal.
 //
 // This Unmarshal allocates considerably less memory.
-func Unmarshal(b []byte, v interface{}) error {
+func Unmarshal(b []byte, v any) error {
 	d := decoderPool.Get().(*decoder)
 	d.r.Reset(b)
 	off := d.dec.InputOffset()

util/jsonutil/unmarshal_test.go

@@ -27,7 +27,7 @@ func TestCompareToStd(t *testing.T) {
 
 	for _, test := range tests {
 		b := []byte(test)
-		var ourV, stdV interface{}
+		var ourV, stdV any
 		ourErr := Unmarshal(b, &ourV)
 		stdErr := json.Unmarshal(b, &stdV)
 		if (ourErr == nil) != (stdErr == nil) {
@@ -47,7 +47,7 @@ func TestCompareToStd(t *testing.T) {
 }
 
 func BenchmarkUnmarshal(b *testing.B) {
-	var m interface{}
+	var m any
 	j := []byte("5")
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {
@@ -56,7 +56,7 @@ func BenchmarkUnmarshal(b *testing.B) {
 }
 
 func BenchmarkStdUnmarshal(b *testing.B) {
-	var m interface{}
+	var m any
 	j := []byte("5")
 	b.ReportAllocs()
 	for i := 0; i < b.N; i++ {

util/multierr/multierr.go

@@ -78,7 +78,7 @@ func (e Error) Is(target error) bool {
 
 // As finds the first error in e that matches target, and if any is found,
 // sets target to that error value and returns true. Otherwise, it returns false.
-func (e Error) As(target interface{}) bool {
+func (e Error) As(target any) bool {
 	for _, err := range e.errs {
 		if ok := errors.As(err, target); ok {
 			return true

util/systemd/systemd_linux.go

@@ -25,7 +25,7 @@ type logOnce struct {
 	sync.Once
 }
 
-func (l *logOnce) logf(format string, args ...interface{}) {
+func (l *logOnce) logf(format string, args ...any) {
 	l.Once.Do(func() {
 		log.Printf(format, args...)
 	})
@@ -71,7 +71,7 @@ func Ready() {
 //    CPU: 2min 38.469s
 //    CGroup: /system.slice/tailscale.service
 //    └─26741 /nix/store/sv6cj4mw2jajm9xkbwj07k29dj30lh0n-tailscale-date.20200727/bin/tailscaled --port 41641
-func Status(format string, args ...interface{}) {
+func Status(format string, args ...any) {
 	err := notifier().Notify(sdnotify.Statusf(format, args...))
 	if err != nil {
 		statusOnce.logf("systemd: error notifying: %v", err)

util/systemd/systemd_nonlinux.go

@@ -7,5 +7,5 @@
 
 package systemd
 
-func Ready()                        {}
+func Ready()                {}
-func Status(string, ...interface{}) {}
+func Status(string, ...any) {}

util/uniq/slice.go

@@ -23,7 +23,7 @@ func (e badTypeError) Error() string {
 // It adjusts the length of the slice appropriately and zeros the tail.
 // eq reports whether (*sliceptr)[i] and (*sliceptr)[j] are equal.
 // ModifySlice does O(len(*sliceptr)) operations.
-func ModifySlice(sliceptr interface{}, eq func(i, j int) bool) {
+func ModifySlice(sliceptr any, eq func(i, j int) bool) {
 	rvp := reflect.ValueOf(sliceptr)
 	if rvp.Type().Kind() != reflect.Ptr {
 		panic(badTypeError{rvp.Type()})

wf/firewall.go

@@ -276,7 +276,7 @@ func (f *Firewall) permitNDP(w weight) error {
 	fieldICMPType := wf.FieldIPLocalPort
 	fieldICMPCode := wf.FieldIPRemotePort
 
-	var icmpConditions = func(t, c uint16, remoteAddress interface{}) []*wf.Match {
+	var icmpConditions = func(t, c uint16, remoteAddress any) []*wf.Match {
 		conditions := []*wf.Match{
 			{
 				Field: wf.FieldIPProtocol,
@@ -359,7 +359,7 @@ func (f *Firewall) permitNDP(w weight) error {
 }
 
 func (f *Firewall) permitDHCPv6(w weight) error {
-	var dhcpConditions = func(remoteAddrs ...interface{}) []*wf.Match {
+	var dhcpConditions = func(remoteAddrs ...any) []*wf.Match {
 		conditions := []*wf.Match{
 			{
 				Field: wf.FieldIPProtocol,
@@ -403,7 +403,7 @@ func (f *Firewall) permitDHCPv6(w weight) error {
 }
 
 func (f *Firewall) permitDHCPv4(w weight) error {
-	var dhcpConditions = func(remoteAddrs ...interface{}) []*wf.Match {
+	var dhcpConditions = func(remoteAddrs ...any) []*wf.Match {
 		conditions := []*wf.Match{
 			{
 				Field: wf.FieldIPProtocol,

wgengine/filter/filter_test.go

@@ -432,7 +432,7 @@ func TestLoggingPrivacy(t *testing.T) {
 		logged     bool
 		testLogger logger.Logf
 	)
-	logf := func(format string, args ...interface{}) {
+	logf := func(format string, args ...any) {
 		testLogger(format, args...)
 		logged = true
 	}

wgengine/magicsock/magicsock.go

@@ -1197,7 +1197,7 @@ var errDropDerpPacket = errors.New("too many DERP packets queued; dropping")
 var errNoUDP = errors.New("no UDP available on platform")
 
 var udpAddrPool = &sync.Pool{
-	New: func() interface{} { return new(net.UDPAddr) },
+	New: func() any { return new(net.UDPAddr) },
 }
 
 // sendUDP sends UDP packet b to ipp.

wgengine/magicsock/magicsock_test.go

@@ -543,7 +543,7 @@ func makeNestable(t *testing.T) (logf logger.Logf, setT func(t *testing.T)) {
 		mu.Unlock()
 	}
 
-	logf = func(s string, args ...interface{}) {
+	logf = func(s string, args ...any) {
 		mu.RLock()
 		t := cur
 
@@ -922,7 +922,7 @@ func testActiveDiscovery(t *testing.T, d *devices) {
 	setT(t)
 
 	start := time.Now()
-	wlogf := func(msg string, args ...interface{}) {
+	wlogf := func(msg string, args ...any) {
 		t.Helper()
 		msg = fmt.Sprintf("%s: %s", time.Since(start).Truncate(time.Microsecond), msg)
 		tlogf(msg, args...)

wgengine/monitor/monitor.go

@@ -340,7 +340,7 @@ func (m *Mon) debounce() {
 	}
 }
 
-func jsonSummary(x interface{}) interface{} {
+func jsonSummary(x any) any {
 	j, err := json.Marshal(x)
 	if err != nil {
 		return err

wgengine/monitor/monitor_darwin.go

@@ -178,7 +178,7 @@ func ipOfAddr(a route.Addr) netaddr.IP {
 	return netaddr.IP{}
 }
 
-func fmtAddr(a route.Addr) interface{} {
+func fmtAddr(a route.Addr) any {
 	if a == nil {
 		return nil
 	}

wgengine/netstack/netstack_test.go

@@ -21,7 +21,7 @@ import (
 func TestInjectInboundLeak(t *testing.T) {
 	tunDev := tstun.NewFake()
 	dialer := new(tsdial.Dialer)
-	logf := func(format string, args ...interface{}) {
+	logf := func(format string, args ...any) {
 		if !t.Failed() {
 			t.Logf(format, args...)
 		}

wgengine/router/router_linux.go

@@ -84,7 +84,7 @@ type netfilterRunner interface {
 
 type linuxRouter struct {
 	closed           syncs.AtomicBool
-	logf             func(fmt string, args ...interface{})
+	logf             func(fmt string, args ...any)
 	tunname          string
 	linkMon          *monitor.Mon
 	unregLinkMon     func()

wgengine/router/router_windows.go

@@ -28,7 +28,7 @@ import (
 )
 
 type winRouter struct {
-	logf                func(fmt string, args ...interface{})
+	logf                func(fmt string, args ...any)
 	linkMon             *monitor.Mon // may be nil
 	nativeTun           *tun.NativeTun
 	routeChangeCallback *winipcfg.RouteChangeCallback

wgengine/watchdog.go

@@ -44,8 +44,8 @@ func NewWatchdog(e Engine) Engine {
 
 type watchdogEngine struct {
 	wrap    Engine
-	logf    func(format string, args ...interface{})
+	logf    func(format string, args ...any)
-	fatalf  func(format string, args ...interface{})
+	fatalf  func(format string, args ...any)
 	maxWait time.Duration
 }
 

wgengine/watchdog_test.go

@@ -57,7 +57,7 @@ func TestWatchdog(t *testing.T) {
 		logBuf := new(tstest.MemLogger)
 		fatalCalled := make(chan struct{})
 		wdEngine.logf = logBuf.Logf
-		wdEngine.fatalf = func(format string, args ...interface{}) {
+		wdEngine.fatalf = func(format string, args ...any) {
 			t.Logf("FATAL: %s", fmt.Sprintf(format, args...))
 			fatalCalled <- struct{}{}
 		}

wgengine/wgcfg/parser_test.go

@@ -25,7 +25,7 @@ func noError(t *testing.T, err error) bool {
 	return false
 }
 
-func equal(t *testing.T, expected, actual interface{}) bool {
+func equal(t *testing.T, expected, actual any) bool {
 	if reflect.DeepEqual(expected, actual) {
 		return true
 	}

wgengine/wglog/wglog.go

@@ -37,7 +37,7 @@ type strCache struct {
 // and rewrites peer keys from wireguard-go into Tailscale format.
 func NewLogger(logf logger.Logf) *Logger {
 	ret := new(Logger)
-	wrapper := func(format string, args ...interface{}) {
+	wrapper := func(format string, args ...any) {
 		if strings.Contains(format, "Routine:") && !strings.Contains(format, "receive incoming") {
 			// wireguard-go logs as it starts and stops routines.
 			// Drop those; there are a lot of them, and they're just noise.
@@ -60,7 +60,7 @@ func NewLogger(logf logger.Logf) *Logger {
 		}
 		// Duplicate the args slice so that we can modify it.
 		// This is not always required, but the code required to avoid it is not worth the complexity.
-		newargs := make([]interface{}, len(args))
+		newargs := make([]any, len(args))
 		copy(newargs, args)
 		for i, arg := range newargs {
 			// We want to replace *device.Peer args with the Tailscale-formatted version of themselves.

wgengine/wglog/wglog_test.go

@@ -18,22 +18,22 @@ import (
 func TestLogger(t *testing.T) {
 	tests := []struct {
 		format string
-		args   []interface{}
+		args   []any
 		want   string
 		omit   bool
 	}{
 		{"hi", nil, "hi", false},
 		{"Routine: starting", nil, "", true},
-		{"%v says it misses you", []interface{}{stringer("peer(IMTB…r7lM)")}, "[IMTBr] says it misses you", false},
+		{"%v says it misses you", []any{stringer("peer(IMTB…r7lM)")}, "[IMTBr] says it misses you", false},
 	}
 
 	type log struct {
 		format string
-		args   []interface{}
+		args   []any
 	}
 
 	c := make(chan log, 1)
-	logf := func(format string, args ...interface{}) {
+	logf := func(format string, args ...any) {
 		select {
 		case c <- log{format, args}:
 		default: