diff --git a/cmd/protoc-gen-go/annotation_test.go b/cmd/protoc-gen-go/annotation_test.go
index 4ec1a2ba..d0fc959a 100644
--- a/cmd/protoc-gen-go/annotation_test.go
+++ b/cmd/protoc-gen-go/annotation_test.go
@@ -6,7 +6,7 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -19,11 +19,11 @@ import (
 )
 
 func TestAnnotations(t *testing.T) {
-	sourceFile, err := ioutil.ReadFile("testdata/annotations/annotations.pb.go")
+	sourceFile, err := os.ReadFile("testdata/annotations/annotations.pb.go")
 	if err != nil {
 		t.Fatal(err)
 	}
-	metaFile, err := ioutil.ReadFile("testdata/annotations/annotations.pb.go.meta")
+	metaFile, err := os.ReadFile("testdata/annotations/annotations.pb.go.meta")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/cmd/protoc-gen-go/internal_gengo/main.go b/cmd/protoc-gen-go/internal_gengo/main.go
index 40e5f050..af3b35e2 100644
--- a/cmd/protoc-gen-go/internal_gengo/main.go
+++ b/cmd/protoc-gen-go/internal_gengo/main.go
@@ -231,7 +231,7 @@ func genImport(gen *protogen.Plugin, g *protogen.GeneratedFile, f *fileInfo, imp
 
 func genEnum(g *protogen.GeneratedFile, f *fileInfo, e *enumInfo) {
 	// Enum type declaration.
-	g.Annotate(e.GoIdent.GoName, e.Location)
+	g.AnnotateSymbol(e.GoIdent.GoName, protogen.Annotation{Location: e.Location})
 	leadingComments := appendDeprecationSuffix(e.Comments.Leading,
 		e.Desc.ParentFile(),
 		e.Desc.Options().(*descriptorpb.EnumOptions).GetDeprecated())
@@ -241,7 +241,7 @@ func genEnum(g *protogen.GeneratedFile, f *fileInfo, e *enumInfo) {
 	// Enum value constants.
 	g.P("const (")
 	for _, value := range e.Values {
-		g.Annotate(value.GoIdent.GoName, value.Location)
+		g.AnnotateSymbol(value.GoIdent.GoName, protogen.Annotation{Location: value.Location})
 		leadingComments := appendDeprecationSuffix(value.Comments.Leading,
 			value.Desc.ParentFile(),
 			value.Desc.Options().(*descriptorpb.EnumValueOptions).GetDeprecated())
@@ -331,7 +331,7 @@ func genMessage(g *protogen.GeneratedFile, f *fileInfo, m *messageInfo) {
 	}
 
 	// Message type declaration.
-	g.Annotate(m.GoIdent.GoName, m.Location)
+	g.AnnotateSymbol(m.GoIdent.GoName, protogen.Annotation{Location: m.Location})
 	leadingComments := appendDeprecationSuffix(m.Comments.Leading,
 		m.Desc.ParentFile(),
 		m.Desc.Options().(*descriptorpb.MessageOptions).GetDeprecated())
@@ -392,7 +392,7 @@ func genMessageField(g *protogen.GeneratedFile, f *fileInfo, m *messageInfo, fie
 			tags = append(tags, gotrackTags...)
 		}
 
-		g.Annotate(m.GoIdent.GoName+"."+oneof.GoName, oneof.Location)
+		g.AnnotateSymbol(m.GoIdent.GoName+"."+oneof.GoName, protogen.Annotation{Location: oneof.Location})
 		leadingComments := oneof.Comments.Leading
 		if leadingComments != "" {
 			leadingComments += "\n"
@@ -431,7 +431,7 @@ func genMessageField(g *protogen.GeneratedFile, f *fileInfo, m *messageInfo, fie
 	if field.Desc.IsWeak() {
 		name = genid.WeakFieldPrefix_goname + name
 	}
-	g.Annotate(m.GoIdent.GoName+"."+name, field.Location)
+	g.AnnotateSymbol(m.GoIdent.GoName+"."+name, protogen.Annotation{Location: field.Location})
 	leadingComments := appendDeprecationSuffix(field.Comments.Leading,
 		field.Desc.ParentFile(),
 		field.Desc.Options().(*descriptorpb.FieldOptions).GetDeprecated())
@@ -559,7 +559,7 @@ func genMessageGetterMethods(g *protogen.GeneratedFile, f *fileInfo, m *messageI
 
 		// Getter for parent oneof.
 		if oneof := field.Oneof; oneof != nil && oneof.Fields[0] == field && !oneof.Desc.IsSynthetic() {
-			g.Annotate(m.GoIdent.GoName+".Get"+oneof.GoName, oneof.Location)
+			g.AnnotateSymbol(m.GoIdent.GoName+".Get"+oneof.GoName, protogen.Annotation{Location: oneof.Location})
 			g.P("func (m *", m.GoIdent.GoName, ") Get", oneof.GoName, "() ", oneofInterfaceName(oneof), " {")
 			g.P("if m != nil {")
 			g.P("return m.", oneof.GoName)
@@ -572,7 +572,7 @@ func genMessageGetterMethods(g *protogen.GeneratedFile, f *fileInfo, m *messageI
 		// Getter for message field.
 		goType, pointer := fieldGoType(g, f, field)
 		defaultValue := fieldDefaultValue(g, f, m, field)
-		g.Annotate(m.GoIdent.GoName+".Get"+field.GoName, field.Location)
+		g.AnnotateSymbol(m.GoIdent.GoName+".Get"+field.GoName, protogen.Annotation{Location: field.Location})
 		leadingComments := appendDeprecationSuffix("",
 			field.Desc.ParentFile(),
 			field.Desc.Options().(*descriptorpb.FieldOptions).GetDeprecated())
@@ -815,8 +815,8 @@ func genMessageOneofWrapperTypes(g *protogen.GeneratedFile, f *fileInfo, m *mess
 		g.P("}")
 		g.P()
 		for _, field := range oneof.Fields {
-			g.Annotate(field.GoIdent.GoName, field.Location)
-			g.Annotate(field.GoIdent.GoName+"."+field.GoName, field.Location)
+			g.AnnotateSymbol(field.GoIdent.GoName, protogen.Annotation{Location: field.Location})
+			g.AnnotateSymbol(field.GoIdent.GoName+"."+field.GoName, protogen.Annotation{Location: field.Location})
 			g.P("type ", field.GoIdent, " struct {")
 			goType, _ := fieldGoType(g, f, field)
 			tags := structTags{
diff --git a/compiler/protogen/protogen.go b/compiler/protogen/protogen.go
index c1044644..b631914d 100644
--- a/compiler/protogen/protogen.go
+++ b/compiler/protogen/protogen.go
@@ -19,7 +19,7 @@ import (
 	"go/printer"
 	"go/token"
 	"go/types"
-	"io/ioutil"
+	"io"
 	"os"
 	"path"
 	"path/filepath"
@@ -60,7 +60,7 @@ func run(opts Options, f func(*Plugin) error) error {
 	if len(os.Args) > 1 {
 		return fmt.Errorf("unknown argument %q (this program should be run by protoc, not directly)", os.Args[1])
 	}
-	in, err := ioutil.ReadAll(os.Stdin)
+	in, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		return err
 	}
diff --git a/integration_test.go b/integration_test.go
index 856340ad..46876cb8 100644
--- a/integration_test.go
+++ b/integration_test.go
@@ -14,7 +14,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"os/exec"
@@ -229,14 +228,16 @@ func mustInitDeps(t *testing.T) {
 	// Delete other sub-directories that are no longer relevant.
 	defer func() {
 		now := time.Now()
-		fis, _ := ioutil.ReadDir(testDir)
+		fis, _ := os.ReadDir(testDir)
 		for _, fi := range fis {
 			dir := filepath.Join(testDir, fi.Name())
 			if finishedDirs[dir] {
 				os.Chtimes(dir, now, now) // best-effort
 				continue
 			}
-			if now.Sub(fi.ModTime()) < purgeTimeout {
+			fii, err := fi.Info()
+			check(err)
+			if now.Sub(fii.ModTime()) < purgeTimeout {
 				continue
 			}
 			fmt.Printf("delete %v\n", fi.Name())
@@ -373,7 +374,7 @@ func downloadArchive(check func(error), dstPath, srcURL, skipPrefix, wantSHA256
 
 	var r io.Reader = resp.Body
 	if wantSHA256 != "" {
-		b, err := ioutil.ReadAll(resp.Body)
+		b, err := io.ReadAll(resp.Body)
 		check(err)
 		r = bytes.NewReader(b)
 
@@ -408,9 +409,9 @@ func downloadArchive(check func(error), dstPath, srcURL, skipPrefix, wantSHA256
 		mode := os.FileMode(h.Mode & 0777)
 		switch h.Typeflag {
 		case tar.TypeReg:
-			b, err := ioutil.ReadAll(tr)
+			b, err := io.ReadAll(tr)
 			check(err)
-			check(ioutil.WriteFile(path, b, mode))
+			check(os.WriteFile(path, b, mode))
 		case tar.TypeDir:
 			check(os.Mkdir(path, mode))
 		}
@@ -443,7 +444,7 @@ func mustHandleFlags(t *testing.T) {
 					cmd.mustRun(t, "go", "build", "-trimpath", "-ldflags", "-s -w -buildid=", "-o", binPath, "./cmd/protoc-gen-go")
 
 					// Archive and compress the binary.
-					in, err := ioutil.ReadFile(binPath)
+					in, err := os.ReadFile(binPath)
 					if err != nil {
 						t.Fatal(err)
 					}
@@ -472,7 +473,7 @@ func mustHandleFlags(t *testing.T) {
 						tw.Close()
 						gz.Close()
 					}
-					if err := ioutil.WriteFile(binPath+suffix, out.Bytes(), 0664); err != nil {
+					if err := os.WriteFile(binPath+suffix, out.Bytes(), 0664); err != nil {
 						t.Fatal(err)
 					}
 				}
@@ -499,7 +500,7 @@ func mustHaveCopyrightHeader(t *testing.T, files []string) {
 	var bad []string
 File:
 	for _, file := range files {
-		b, err := ioutil.ReadFile(file)
+		b, err := os.ReadFile(file)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/internal/benchmarks/bench_test.go b/internal/benchmarks/bench_test.go
index 2bf2b981..6112caef 100644
--- a/internal/benchmarks/bench_test.go
+++ b/internal/benchmarks/bench_test.go
@@ -7,7 +7,6 @@ package bench_test
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -175,7 +174,7 @@ func TestMain(m *testing.M) {
 		if filepath.Ext(path) != ".pb" {
 			return nil
 		}
-		raw, err := ioutil.ReadFile(path)
+		raw, err := os.ReadFile(path)
 		if err != nil {
 			panic(err)
 		}
diff --git a/internal/cmd/generate-corpus/main.go b/internal/cmd/generate-corpus/main.go
index 8f77dea9..6aa03dc8 100644
--- a/internal/cmd/generate-corpus/main.go
+++ b/internal/cmd/generate-corpus/main.go
@@ -12,8 +12,8 @@ package main
 import (
 	"crypto/sha1"
 	"fmt"
-	"io/ioutil"
 	"log"
+	"os"
 
 	"google.golang.org/protobuf/encoding/protojson"
 	"google.golang.org/protobuf/encoding/prototext"
@@ -114,7 +114,7 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		if err := ioutil.WriteFile(fmt.Sprintf("internal/fuzz/wirefuzz/corpus/%x", sha1.Sum(wire)), wire, 0777); err != nil {
+		if err := os.WriteFile(fmt.Sprintf("internal/fuzz/wirefuzz/corpus/%x", sha1.Sum(wire)), wire, 0777); err != nil {
 			log.Fatal(err)
 		}
 
@@ -122,7 +122,7 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		if err := ioutil.WriteFile(fmt.Sprintf("internal/fuzz/textfuzz/corpus/%x", sha1.Sum(text)), text, 0777); err != nil {
+		if err := os.WriteFile(fmt.Sprintf("internal/fuzz/textfuzz/corpus/%x", sha1.Sum(text)), text, 0777); err != nil {
 			log.Fatal(err)
 		}
 
@@ -130,7 +130,7 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		if err := ioutil.WriteFile(fmt.Sprintf("internal/fuzz/jsonfuzz/corpus/%x", sha1.Sum(json)), json, 0777); err != nil {
+		if err := os.WriteFile(fmt.Sprintf("internal/fuzz/jsonfuzz/corpus/%x", sha1.Sum(json)), json, 0777); err != nil {
 			log.Fatal(err)
 		}
 	}
diff --git a/internal/cmd/generate-protos/main.go b/internal/cmd/generate-protos/main.go
index 6724775c..e0ba3a66 100644
--- a/internal/cmd/generate-protos/main.go
+++ b/internal/cmd/generate-protos/main.go
@@ -11,7 +11,6 @@ import (
 	"flag"
 	"fmt"
 	"go/format"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -126,7 +125,7 @@ func generateEditionsDefaults() {
 }
 
 func generateLocalProtos() {
-	tmpDir, err := ioutil.TempDir(repoRoot, "tmp")
+	tmpDir, err := os.MkdirTemp(repoRoot, "tmp")
 	check(err)
 	defer os.RemoveAll(tmpDir)
 
@@ -197,7 +196,7 @@ func generateLocalProtos() {
 			}...), "\n")
 			b, err := format.Source([]byte(s))
 			check(err)
-			check(ioutil.WriteFile(filepath.Join(tmpDir, filepath.FromSlash(d.path+"/gen_test.go")), b, 0664))
+			check(os.WriteFile(filepath.Join(tmpDir, filepath.FromSlash(d.path+"/gen_test.go")), b, 0664))
 		}
 	}
 
@@ -205,7 +204,7 @@ func generateLocalProtos() {
 }
 
 func generateRemoteProtos() {
-	tmpDir, err := ioutil.TempDir(repoRoot, "tmp")
+	tmpDir, err := os.MkdirTemp(repoRoot, "tmp")
 	check(err)
 	defer os.RemoveAll(tmpDir)
 
@@ -466,14 +465,14 @@ func syncOutput(dstDir, srcDir string) {
 }
 
 func copyFile(dstPath, srcPath string) (changed bool) {
-	src, err := ioutil.ReadFile(srcPath)
+	src, err := os.ReadFile(srcPath)
 	check(err)
 	check(os.MkdirAll(filepath.Dir(dstPath), 0775))
-	dst, _ := ioutil.ReadFile(dstPath)
+	dst, _ := os.ReadFile(dstPath)
 	if bytes.Equal(src, dst) {
 		return false
 	}
-	check(ioutil.WriteFile(dstPath, src, 0664))
+	check(os.WriteFile(dstPath, src, 0664))
 	return true
 }
 
diff --git a/internal/cmd/generate-types/main.go b/internal/cmd/generate-types/main.go
index 53f3721b..9a7460c9 100644
--- a/internal/cmd/generate-types/main.go
+++ b/internal/cmd/generate-types/main.go
@@ -11,7 +11,6 @@ import (
 	"flag"
 	"fmt"
 	"go/format"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -248,13 +247,13 @@ func writeSource(file, src string) {
 
 	absFile := filepath.Join(repoRoot, file)
 	if run {
-		prev, _ := ioutil.ReadFile(absFile)
+		prev, _ := os.ReadFile(absFile)
 		if !bytes.Equal(b, prev) {
 			fmt.Println("#", file)
-			check(ioutil.WriteFile(absFile, b, 0664))
+			check(os.WriteFile(absFile, b, 0664))
 		}
 	} else {
-		check(ioutil.WriteFile(absFile+".tmp", b, 0664))
+		check(os.WriteFile(absFile+".tmp", b, 0664))
 		defer os.Remove(absFile + ".tmp")
 
 		cmd := exec.Command("diff", file, file+".tmp", "-N", "-u")
diff --git a/internal/cmd/pbdump/pbdump.go b/internal/cmd/pbdump/pbdump.go
index befb8310..b3ea3eb8 100644
--- a/internal/cmd/pbdump/pbdump.go
+++ b/internal/cmd/pbdump/pbdump.go
@@ -9,7 +9,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
@@ -111,14 +111,14 @@ func main() {
 	// Read message input.
 	var buf []byte
 	if flag.NArg() == 0 {
-		b, err := ioutil.ReadAll(os.Stdin)
+		b, err := io.ReadAll(os.Stdin)
 		if err != nil {
 			log.Fatalf("ReadAll error: %v", err)
 		}
 		buf = b
 	}
 	for _, f := range flag.Args() {
-		b, err := ioutil.ReadFile(f)
+		b, err := os.ReadFile(f)
 		if err != nil {
 			log.Fatalf("ReadFile error: %v", err)
 		}
diff --git a/internal/filedesc/build_test.go b/internal/filedesc/build_test.go
index 979b8ea1..8dd7323b 100644
--- a/internal/filedesc/build_test.go
+++ b/internal/filedesc/build_test.go
@@ -7,7 +7,7 @@ package filedesc_test
 import (
 	"bytes"
 	"compress/gzip"
-	"io/ioutil"
+	"io"
 	"testing"
 
 	"google.golang.org/protobuf/proto"
@@ -33,7 +33,7 @@ func TestInit(t *testing.T) {
 	want := &descriptorpb.FileDescriptorProto{}
 	zb, _ := (&testpb.TestAllTypes{}).Descriptor()
 	r, _ := gzip.NewReader(bytes.NewBuffer(zb))
-	b, _ := ioutil.ReadAll(r)
+	b, _ := io.ReadAll(r)
 	if err := proto.Unmarshal(b, want); err != nil {
 		t.Fatal(err)
 	}
diff --git a/internal/fuzztest/fuzztest.go b/internal/fuzztest/fuzztest.go
index 2b54eb59..5f0625cd 100644
--- a/internal/fuzztest/fuzztest.go
+++ b/internal/fuzztest/fuzztest.go
@@ -7,7 +7,6 @@ package fuzztest
 
 import (
 	"flag"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -34,7 +33,7 @@ func Test(t *testing.T, fuzz func(b []byte) int) {
 	sort.Strings(names)
 	for _, name := range names {
 		t.Run(name, func(t *testing.T) {
-			b, err := ioutil.ReadFile(filepath.Join(*corpus, name))
+			b, err := os.ReadFile(filepath.Join(*corpus, name))
 			if err != nil {
 				t.Fatal(err)
 			}
diff --git a/internal/impl/legacy_export_test.go b/internal/impl/legacy_export_test.go
index e1d2c08b..a9ce6a75 100644
--- a/internal/impl/legacy_export_test.go
+++ b/internal/impl/legacy_export_test.go
@@ -7,7 +7,7 @@ package impl
 import (
 	"bytes"
 	"compress/gzip"
-	"io/ioutil"
+	"io"
 	"math"
 	"strings"
 	"testing"
@@ -30,7 +30,7 @@ func TestCompressGZIP(t *testing.T) {
 		if err != nil {
 			t.Errorf("unexpected gzip.NewReader error: %v", err)
 		}
-		b, err := ioutil.ReadAll(zr)
+		b, err := io.ReadAll(zr)
 		if err != nil {
 			t.Errorf("unexpected ioutil.ReadAll error: %v", err)
 		}
diff --git a/internal/impl/legacy_file.go b/internal/impl/legacy_file.go
index 9ab09108..b649f112 100644
--- a/internal/impl/legacy_file.go
+++ b/internal/impl/legacy_file.go
@@ -7,7 +7,7 @@ package impl
 import (
 	"bytes"
 	"compress/gzip"
-	"io/ioutil"
+	"io"
 	"sync"
 
 	"google.golang.org/protobuf/internal/filedesc"
@@ -51,7 +51,7 @@ func legacyLoadFileDesc(b []byte) protoreflect.FileDescriptor {
 	if err != nil {
 		panic(err)
 	}
-	b2, err := ioutil.ReadAll(zr)
+	b2, err := io.ReadAll(zr)
 	if err != nil {
 		panic(err)
 	}
diff --git a/internal/impl/legacy_file_test.go b/internal/impl/legacy_file_test.go
index 66600eec..f08eb024 100644
--- a/internal/impl/legacy_file_test.go
+++ b/internal/impl/legacy_file_test.go
@@ -7,7 +7,7 @@ package impl_test
 import (
 	"bytes"
 	"compress/gzip"
-	"io/ioutil"
+	"io"
 	"reflect"
 	"testing"
 
@@ -39,7 +39,7 @@ func mustLoadFileDesc(b []byte, _ []int) protoreflect.FileDescriptor {
 	if err != nil {
 		panic(err)
 	}
-	b, err = ioutil.ReadAll(zr)
+	b, err = io.ReadAll(zr)
 	if err != nil {
 		panic(err)
 	}
diff --git a/internal/protolegacy/proto.go b/internal/protolegacy/proto.go
index 96b44d91..7c091939 100644
--- a/internal/protolegacy/proto.go
+++ b/internal/protolegacy/proto.go
@@ -11,7 +11,7 @@ import (
 	"compress/gzip"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 
 	"google.golang.org/protobuf/reflect/protoreflect"
 	"google.golang.org/protobuf/reflect/protoregistry"
@@ -48,7 +48,7 @@ func RegisterFile(s string, d []byte) {
 	if err != nil {
 		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))
 	}
-	b, err := ioutil.ReadAll(zr)
+	b, err := io.ReadAll(zr)
 	if err != nil {
 		panic(fmt.Sprintf("proto: invalid compressed file descriptor: %v", err))
 	}