diff --git a/src/archive/tar/reader_test.go b/src/archive/tar/reader_test.go
index 411d1e0b99..789ddc1bc0 100644
--- a/src/archive/tar/reader_test.go
+++ b/src/archive/tar/reader_test.go
@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"path"
@@ -773,7 +772,7 @@ func TestReadTruncation(t *testing.T) {
 		"testdata/pax-path-hdr.tar",
 		"testdata/sparse-formats.tar",
 	} {
-		buf, err := ioutil.ReadFile(p)
+		buf, err := os.ReadFile(p)
 		if err != nil {
 			t.Fatalf("unexpected error: %v", err)
 		}
diff --git a/src/archive/tar/tar_test.go b/src/archive/tar/tar_test.go
index d4a3d42312..91b38401b6 100644
--- a/src/archive/tar/tar_test.go
+++ b/src/archive/tar/tar_test.go
@@ -11,7 +11,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"math"
 	"os"
 	"path"
@@ -263,7 +262,7 @@ func TestFileInfoHeaderDir(t *testing.T) {
 func TestFileInfoHeaderSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestFileInfoHeaderSymlink")
+	tmpdir, err := os.MkdirTemp("", "TestFileInfoHeaderSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
index 30556d27d0..a00f02d8fa 100644
--- a/src/archive/tar/writer_test.go
+++ b/src/archive/tar/writer_test.go
@@ -9,7 +9,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"io"
-	"io/ioutil"
 	"os"
 	"path"
 	"reflect"
@@ -520,7 +519,7 @@ func TestWriter(t *testing.T) {
 			}
 
 			if v.file != "" {
-				want, err := ioutil.ReadFile(v.file)
+				want, err := os.ReadFile(v.file)
 				if err != nil {
 					t.Fatalf("ReadFile() = %v, want nil", err)
 				}
diff --git a/src/archive/zip/reader_test.go b/src/archive/zip/reader_test.go
index b7a7d7a757..34e96f7da4 100644
--- a/src/archive/zip/reader_test.go
+++ b/src/archive/zip/reader_test.go
@@ -11,7 +11,6 @@ import (
 	"internal/obscuretestdata"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"regexp"
@@ -629,7 +628,7 @@ func readTestFile(t *testing.T, zt ZipTest, ft ZipTestFile, f *File) {
 	var c []byte
 	if ft.Content != nil {
 		c = ft.Content
-	} else if c, err = ioutil.ReadFile("testdata/" + ft.File); err != nil {
+	} else if c, err = os.ReadFile("testdata/" + ft.File); err != nil {
 		t.Error(err)
 		return
 	}
@@ -685,7 +684,7 @@ func TestInvalidFiles(t *testing.T) {
 }
 
 func messWith(fileName string, corrupter func(b []byte)) (r io.ReaderAt, size int64) {
-	data, err := ioutil.ReadFile(filepath.Join("testdata", fileName))
+	data, err := os.ReadFile(filepath.Join("testdata", fileName))
 	if err != nil {
 		panic("Error reading " + fileName + ": " + err.Error())
 	}
@@ -792,17 +791,17 @@ func returnRecursiveZip() (r io.ReaderAt, size int64) {
 //
 //	func main() {
 //		bigZip := makeZip("big.file", io.LimitReader(zeros{}, 1<<32-1))
-//		if err := ioutil.WriteFile("/tmp/big.zip", bigZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/big.zip", bigZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //
 //		biggerZip := makeZip("big.zip", bytes.NewReader(bigZip))
-//		if err := ioutil.WriteFile("/tmp/bigger.zip", biggerZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/bigger.zip", biggerZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //
 //		biggestZip := makeZip("bigger.zip", bytes.NewReader(biggerZip))
-//		if err := ioutil.WriteFile("/tmp/biggest.zip", biggestZip, 0666); err != nil {
+//		if err := os.WriteFile("/tmp/biggest.zip", biggestZip, 0666); err != nil {
 //			log.Fatal(err)
 //		}
 //	}
diff --git a/src/archive/zip/writer_test.go b/src/archive/zip/writer_test.go
index 2c32eaf4a5..5985144e5c 100644
--- a/src/archive/zip/writer_test.go
+++ b/src/archive/zip/writer_test.go
@@ -10,8 +10,8 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"math/rand"
+	"os"
 	"strings"
 	"testing"
 	"time"
@@ -237,7 +237,7 @@ func TestWriterTime(t *testing.T) {
 		t.Fatalf("unexpected Close error: %v", err)
 	}
 
-	want, err := ioutil.ReadFile("testdata/time-go.zip")
+	want, err := os.ReadFile("testdata/time-go.zip")
 	if err != nil {
 		t.Fatalf("unexpected ReadFile error: %v", err)
 	}
diff --git a/src/cmd/addr2line/addr2line_test.go b/src/cmd/addr2line/addr2line_test.go
index 7973aa2fe1..992d7ac11e 100644
--- a/src/cmd/addr2line/addr2line_test.go
+++ b/src/cmd/addr2line/addr2line_test.go
@@ -8,7 +8,6 @@ import (
 	"bufio"
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -98,8 +97,8 @@ func testAddr2Line(t *testing.T, exepath, addr string) {
 	if !os.SameFile(fi1, fi2) {
 		t.Fatalf("addr2line_test.go and %s are not same file", srcPath)
 	}
-	if srcLineNo != "107" {
-		t.Fatalf("line number = %v; want 107", srcLineNo)
+	if srcLineNo != "106" {
+		t.Fatalf("line number = %v; want 106", srcLineNo)
 	}
 }
 
@@ -107,7 +106,7 @@ func testAddr2Line(t *testing.T, exepath, addr string) {
 func TestAddr2Line(t *testing.T) {
 	testenv.MustHaveGoBuild(t)
 
-	tmpDir, err := ioutil.TempDir("", "TestAddr2Line")
+	tmpDir, err := os.MkdirTemp("", "TestAddr2Line")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
diff --git a/src/cmd/api/goapi.go b/src/cmd/api/goapi.go
index b14d57c236..ba42812fa6 100644
--- a/src/cmd/api/goapi.go
+++ b/src/cmd/api/goapi.go
@@ -17,7 +17,6 @@ import (
 	"go/token"
 	"go/types"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -342,7 +341,7 @@ func fileFeatures(filename string) []string {
 	if filename == "" {
 		return nil
 	}
-	bs, err := ioutil.ReadFile(filename)
+	bs, err := os.ReadFile(filename)
 	if err != nil {
 		log.Fatalf("Error reading file %s: %v", filename, err)
 	}
diff --git a/src/cmd/api/goapi_test.go b/src/cmd/api/goapi_test.go
index 24620a94af..16e0058e5e 100644
--- a/src/cmd/api/goapi_test.go
+++ b/src/cmd/api/goapi_test.go
@@ -9,7 +9,6 @@ import (
 	"flag"
 	"fmt"
 	"go/build"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -75,7 +74,7 @@ func TestGolden(t *testing.T) {
 			f.Close()
 		}
 
-		bs, err := ioutil.ReadFile(goldenFile)
+		bs, err := os.ReadFile(goldenFile)
 		if err != nil {
 			t.Fatalf("opening golden.txt for package %q: %v", fi.Name(), err)
 		}
diff --git a/src/cmd/cover/cover.go b/src/cmd/cover/cover.go
index 360f9aeb06..7ee000861b 100644
--- a/src/cmd/cover/cover.go
+++ b/src/cmd/cover/cover.go
@@ -12,7 +12,6 @@ import (
 	"go/parser"
 	"go/token"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"sort"
@@ -304,7 +303,7 @@ func (f *File) Visit(node ast.Node) ast.Visitor {
 
 func annotate(name string) {
 	fset := token.NewFileSet()
-	content, err := ioutil.ReadFile(name)
+	content, err := os.ReadFile(name)
 	if err != nil {
 		log.Fatalf("cover: %s: %s", name, err)
 	}
diff --git a/src/cmd/cover/cover_test.go b/src/cmd/cover/cover_test.go
index 1c252e6e45..86c95d15c5 100644
--- a/src/cmd/cover/cover_test.go
+++ b/src/cmd/cover/cover_test.go
@@ -13,7 +13,6 @@ import (
 	"go/parser"
 	"go/token"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -81,7 +80,7 @@ var debug = flag.Bool("debug", false, "keep rewritten files for debugging")
 // We use TestMain to set up a temporary directory and remove it when
 // the tests are done.
 func TestMain(m *testing.M) {
-	dir, err := ioutil.TempDir("", "go-testcover")
+	dir, err := os.MkdirTemp("", "go-testcover")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
@@ -173,7 +172,7 @@ func TestCover(t *testing.T) {
 	buildCover(t)
 
 	// Read in the test file (testTest) and write it, with LINEs specified, to coverInput.
-	file, err := ioutil.ReadFile(testTest)
+	file, err := os.ReadFile(testTest)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -192,7 +191,7 @@ func TestCover(t *testing.T) {
 		[]byte("}"))
 	lines = append(lines, []byte("func unFormatted2(b bool) {if b{}else{}}"))
 
-	if err := ioutil.WriteFile(coverInput, bytes.Join(lines, []byte("\n")), 0666); err != nil {
+	if err := os.WriteFile(coverInput, bytes.Join(lines, []byte("\n")), 0666); err != nil {
 		t.Fatal(err)
 	}
 
@@ -208,11 +207,11 @@ func TestCover(t *testing.T) {
 
 	// Copy testmain to testTempDir, so that it is in the same directory
 	// as coverOutput.
-	b, err := ioutil.ReadFile(testMain)
+	b, err := os.ReadFile(testMain)
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(tmpTestMain, b, 0444); err != nil {
+	if err := os.WriteFile(tmpTestMain, b, 0444); err != nil {
 		t.Fatal(err)
 	}
 
@@ -220,7 +219,7 @@ func TestCover(t *testing.T) {
 	cmd = exec.Command(testenv.GoToolPath(t), "run", tmpTestMain, coverOutput)
 	run(cmd, t)
 
-	file, err = ioutil.ReadFile(coverOutput)
+	file, err = os.ReadFile(coverOutput)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -251,7 +250,7 @@ func TestDirectives(t *testing.T) {
 	// Read the source file and find all the directives. We'll keep
 	// track of whether each one has been seen in the output.
 	testDirectives := filepath.Join(testdata, "directives.go")
-	source, err := ioutil.ReadFile(testDirectives)
+	source, err := os.ReadFile(testDirectives)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -398,7 +397,7 @@ func TestCoverHTML(t *testing.T) {
 
 	// Extract the parts of the HTML with comment markers,
 	// and compare against a golden file.
-	entireHTML, err := ioutil.ReadFile(htmlHTML)
+	entireHTML, err := os.ReadFile(htmlHTML)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -420,7 +419,7 @@ func TestCoverHTML(t *testing.T) {
 	if scan.Err() != nil {
 		t.Error(scan.Err())
 	}
-	golden, err := ioutil.ReadFile(htmlGolden)
+	golden, err := os.ReadFile(htmlGolden)
 	if err != nil {
 		t.Fatalf("reading golden file: %v", err)
 	}
@@ -457,7 +456,7 @@ func TestHtmlUnformatted(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := ioutil.WriteFile(filepath.Join(htmlUDir, "go.mod"), []byte("module htmlunformatted\n"), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(htmlUDir, "go.mod"), []byte("module htmlunformatted\n"), 0666); err != nil {
 		t.Fatal(err)
 	}
 
@@ -474,10 +473,10 @@ lab:
 
 	const htmlUTestContents = `package htmlunformatted`
 
-	if err := ioutil.WriteFile(htmlU, []byte(htmlUContents), 0444); err != nil {
+	if err := os.WriteFile(htmlU, []byte(htmlUContents), 0444); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(htmlUTest, []byte(htmlUTestContents), 0444); err != nil {
+	if err := os.WriteFile(htmlUTest, []byte(htmlUTestContents), 0444); err != nil {
 		t.Fatal(err)
 	}
 
@@ -540,13 +539,13 @@ func TestFuncWithDuplicateLines(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if err := ioutil.WriteFile(filepath.Join(lineDupDir, "go.mod"), []byte("module linedup\n"), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(lineDupDir, "go.mod"), []byte("module linedup\n"), 0666); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(lineDupGo, []byte(lineDupContents), 0444); err != nil {
+	if err := os.WriteFile(lineDupGo, []byte(lineDupContents), 0444); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(lineDupTestGo, []byte(lineDupTestContents), 0444); err != nil {
+	if err := os.WriteFile(lineDupTestGo, []byte(lineDupTestContents), 0444); err != nil {
 		t.Fatal(err)
 	}
 
diff --git a/src/cmd/cover/html.go b/src/cmd/cover/html.go
index f76ea03cf5..b2865c427c 100644
--- a/src/cmd/cover/html.go
+++ b/src/cmd/cover/html.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"html/template"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"path/filepath"
@@ -43,7 +42,7 @@ func htmlOutput(profile, outfile string) error {
 		if err != nil {
 			return err
 		}
-		src, err := ioutil.ReadFile(file)
+		src, err := os.ReadFile(file)
 		if err != nil {
 			return fmt.Errorf("can't read %q: %v", fn, err)
 		}
@@ -62,7 +61,7 @@ func htmlOutput(profile, outfile string) error {
 	var out *os.File
 	if outfile == "" {
 		var dir string
-		dir, err = ioutil.TempDir("", "cover")
+		dir, err = os.MkdirTemp("", "cover")
 		if err != nil {
 			return err
 		}
diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
index 1cedf992cf..d055929aac 100644
--- a/src/cmd/fix/main.go
+++ b/src/cmd/fix/main.go
@@ -15,7 +15,6 @@ import (
 	"go/token"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -217,7 +216,7 @@ func processFile(filename string, useStdin bool) error {
 		return nil
 	}
 
-	return ioutil.WriteFile(f.Name(), newSrc, 0)
+	return os.WriteFile(f.Name(), newSrc, 0)
 }
 
 func gofmt(n interface{}) string {
diff --git a/src/cmd/fix/typecheck.go b/src/cmd/fix/typecheck.go
index f45155b06d..40b2287f26 100644
--- a/src/cmd/fix/typecheck.go
+++ b/src/cmd/fix/typecheck.go
@@ -9,7 +9,6 @@ import (
 	"go/ast"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -162,12 +161,12 @@ func typecheck(cfg *TypeConfig, f *ast.File) (typeof map[interface{}]string, ass
 			if err != nil {
 				return err
 			}
-			dir, err := ioutil.TempDir(os.TempDir(), "fix_cgo_typecheck")
+			dir, err := os.MkdirTemp(os.TempDir(), "fix_cgo_typecheck")
 			if err != nil {
 				return err
 			}
 			defer os.RemoveAll(dir)
-			err = ioutil.WriteFile(filepath.Join(dir, "in.go"), txt, 0600)
+			err = os.WriteFile(filepath.Join(dir, "in.go"), txt, 0600)
 			if err != nil {
 				return err
 			}
@@ -176,7 +175,7 @@ func typecheck(cfg *TypeConfig, f *ast.File) (typeof map[interface{}]string, ass
 			if err != nil {
 				return err
 			}
-			out, err := ioutil.ReadFile(filepath.Join(dir, "_cgo_gotypes.go"))
+			out, err := os.ReadFile(filepath.Join(dir, "_cgo_gotypes.go"))
 			if err != nil {
 				return err
 			}
diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index 1b8a21ecfa..19764bfc60 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -17,7 +17,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -100,7 +99,7 @@ func TestMain(m *testing.M) {
 
 	// Run with a temporary TMPDIR to check that the tests don't
 	// leave anything behind.
-	topTmpdir, err := ioutil.TempDir("", "cmd-go-test-")
+	topTmpdir, err := os.MkdirTemp("", "cmd-go-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -109,7 +108,7 @@ func TestMain(m *testing.M) {
 	}
 	os.Setenv(tempEnvName(), topTmpdir)
 
-	dir, err := ioutil.TempDir(topTmpdir, "tmpdir")
+	dir, err := os.MkdirTemp(topTmpdir, "tmpdir")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -616,7 +615,7 @@ func (tg *testgoData) makeTempdir() {
 	tg.t.Helper()
 	if tg.tempdir == "" {
 		var err error
-		tg.tempdir, err = ioutil.TempDir("", "gotest")
+		tg.tempdir, err = os.MkdirTemp("", "gotest")
 		tg.must(err)
 	}
 }
@@ -633,7 +632,7 @@ func (tg *testgoData) tempFile(path, contents string) {
 			bytes = formatted
 		}
 	}
-	tg.must(ioutil.WriteFile(filepath.Join(tg.tempdir, path), bytes, 0644))
+	tg.must(os.WriteFile(filepath.Join(tg.tempdir, path), bytes, 0644))
 }
 
 // tempDir adds a temporary directory for a run of testgo.
@@ -833,7 +832,7 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 					return err
 				}
 				dest := filepath.Join("goroot", copydir, srcrel)
-				data, err := ioutil.ReadFile(path)
+				data, err := os.ReadFile(path)
 				if err != nil {
 					return err
 				}
@@ -850,18 +849,18 @@ func TestNewReleaseRebuildsStalePackagesInGOPATH(t *testing.T) {
 	tg.setenv("GOROOT", tg.path("goroot"))
 
 	addVar := func(name string, idx int) (restore func()) {
-		data, err := ioutil.ReadFile(name)
+		data, err := os.ReadFile(name)
 		if err != nil {
 			t.Fatal(err)
 		}
 		old := data
 		data = append(data, fmt.Sprintf("var DummyUnusedVar%d bool\n", idx)...)
-		if err := ioutil.WriteFile(name, append(data, '\n'), 0666); err != nil {
+		if err := os.WriteFile(name, append(data, '\n'), 0666); err != nil {
 			t.Fatal(err)
 		}
 		tg.sleep()
 		return func() {
-			if err := ioutil.WriteFile(name, old, 0666); err != nil {
+			if err := os.WriteFile(name, old, 0666); err != nil {
 				t.Fatal(err)
 			}
 		}
@@ -2674,7 +2673,7 @@ echo $* >>`+tg.path("pkg-config.out"))
 	tg.setenv("GOPATH", tg.path("."))
 	tg.setenv("PKG_CONFIG", tg.path("pkg-config.sh"))
 	tg.run("build", "x")
-	out, err := ioutil.ReadFile(tg.path("pkg-config.out"))
+	out, err := os.ReadFile(tg.path("pkg-config.out"))
 	tg.must(err)
 	out = bytes.TrimSpace(out)
 	want := "--cflags --static --static -- a a\n--libs --static --static -- a a"
diff --git a/src/cmd/go/go_windows_test.go b/src/cmd/go/go_windows_test.go
index 02634f19f5..3094212bae 100644
--- a/src/cmd/go/go_windows_test.go
+++ b/src/cmd/go/go_windows_test.go
@@ -5,7 +5,6 @@
 package main_test
 
 import (
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -20,14 +19,14 @@ func TestAbsolutePath(t *testing.T) {
 	defer tg.cleanup()
 	tg.parallel()
 
-	tmp, err := ioutil.TempDir("", "TestAbsolutePath")
+	tmp, err := os.MkdirTemp("", "TestAbsolutePath")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer robustio.RemoveAll(tmp)
 
 	file := filepath.Join(tmp, "a.go")
-	err = ioutil.WriteFile(file, []byte{}, 0644)
+	err = os.WriteFile(file, []byte{}, 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/help_test.go b/src/cmd/go/help_test.go
index 78d63ff05e..abfc3db993 100644
--- a/src/cmd/go/help_test.go
+++ b/src/cmd/go/help_test.go
@@ -6,7 +6,7 @@ package main_test
 
 import (
 	"bytes"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	"cmd/go/internal/help"
@@ -23,7 +23,7 @@ func TestDocsUpToDate(t *testing.T) {
 	buf := new(bytes.Buffer)
 	// Match the command in mkalldocs.sh that generates alldocs.go.
 	help.Help(buf, []string{"documentation"})
-	data, err := ioutil.ReadFile("alldocs.go")
+	data, err := os.ReadFile("alldocs.go")
 	if err != nil {
 		t.Fatalf("error reading alldocs.go: %v", err)
 	}
diff --git a/src/cmd/go/internal/auth/netrc.go b/src/cmd/go/internal/auth/netrc.go
index 7a9bdbb72c..0107f20d7a 100644
--- a/src/cmd/go/internal/auth/netrc.go
+++ b/src/cmd/go/internal/auth/netrc.go
@@ -5,7 +5,6 @@
 package auth
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -99,7 +98,7 @@ func readNetrc() {
 		return
 	}
 
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		if !os.IsNotExist(err) {
 			netrcErr = err
diff --git a/src/cmd/go/internal/bug/bug.go b/src/cmd/go/internal/bug/bug.go
index 07e3516855..1085feaaee 100644
--- a/src/cmd/go/internal/bug/bug.go
+++ b/src/cmd/go/internal/bug/bug.go
@@ -10,7 +10,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	urlpkg "net/url"
 	"os"
 	"os/exec"
@@ -117,7 +116,7 @@ func printOSDetails(w io.Writer) {
 	case "illumos", "solaris":
 		// Be sure to use the OS-supplied uname, in "/usr/bin":
 		printCmdOut(w, "uname -srv: ", "/usr/bin/uname", "-srv")
-		out, err := ioutil.ReadFile("/etc/release")
+		out, err := os.ReadFile("/etc/release")
 		if err == nil {
 			fmt.Fprintf(w, "/etc/release: %s\n", out)
 		} else {
@@ -177,7 +176,7 @@ func printGlibcVersion(w io.Writer) {
 	src := []byte(`int main() {}`)
 	srcfile := filepath.Join(tempdir, "go-bug.c")
 	outfile := filepath.Join(tempdir, "go-bug")
-	err := ioutil.WriteFile(srcfile, src, 0644)
+	err := os.WriteFile(srcfile, src, 0644)
 	if err != nil {
 		return
 	}
diff --git a/src/cmd/go/internal/cache/cache.go b/src/cmd/go/internal/cache/cache.go
index 5464fe5685..41f921641d 100644
--- a/src/cmd/go/internal/cache/cache.go
+++ b/src/cmd/go/internal/cache/cache.go
@@ -13,7 +13,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -239,7 +238,7 @@ func (c *Cache) GetBytes(id ActionID) ([]byte, Entry, error) {
 	if err != nil {
 		return nil, entry, err
 	}
-	data, _ := ioutil.ReadFile(c.OutputFile(entry.OutputID))
+	data, _ := os.ReadFile(c.OutputFile(entry.OutputID))
 	if sha256.Sum256(data) != entry.OutputID {
 		return nil, entry, &entryNotFoundError{Err: errors.New("bad checksum")}
 	}
@@ -378,7 +377,7 @@ func (c *Cache) putIndexEntry(id ActionID, out OutputID, size int64, allowVerify
 		// Truncate the file only *after* writing it.
 		// (This should be a no-op, but truncate just in case of previous corruption.)
 		//
-		// This differs from ioutil.WriteFile, which truncates to 0 *before* writing
+		// This differs from os.WriteFile, which truncates to 0 *before* writing
 		// via os.O_TRUNC. Truncating only after writing ensures that a second write
 		// of the same content to the same file is idempotent, and does not — even
 		// temporarily! — undo the effect of the first write.
diff --git a/src/cmd/go/internal/cache/cache_test.go b/src/cmd/go/internal/cache/cache_test.go
index 1988c34502..a865b97018 100644
--- a/src/cmd/go/internal/cache/cache_test.go
+++ b/src/cmd/go/internal/cache/cache_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -20,7 +19,7 @@ func init() {
 }
 
 func TestBasic(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -65,7 +64,7 @@ func TestBasic(t *testing.T) {
 }
 
 func TestGrowth(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -118,7 +117,7 @@ func TestVerifyPanic(t *testing.T) {
 		t.Fatal("initEnv did not set verify")
 	}
 
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -151,7 +150,7 @@ func dummyID(x int) [HashSize]byte {
 }
 
 func TestCacheTrim(t *testing.T) {
-	dir, err := ioutil.TempDir("", "cachetest-")
+	dir, err := os.MkdirTemp("", "cachetest-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -207,7 +206,7 @@ func TestCacheTrim(t *testing.T) {
 		t.Fatal(err)
 	}
 	c.OutputFile(entry.OutputID)
-	data, err := ioutil.ReadFile(filepath.Join(dir, "trim.txt"))
+	data, err := os.ReadFile(filepath.Join(dir, "trim.txt"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -220,7 +219,7 @@ func TestCacheTrim(t *testing.T) {
 		t.Fatal(err)
 	}
 	c.OutputFile(entry.OutputID)
-	data2, err := ioutil.ReadFile(filepath.Join(dir, "trim.txt"))
+	data2, err := os.ReadFile(filepath.Join(dir, "trim.txt"))
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/cache/default.go b/src/cmd/go/internal/cache/default.go
index 9f8dd8af4b..0b1c1e0c20 100644
--- a/src/cmd/go/internal/cache/default.go
+++ b/src/cmd/go/internal/cache/default.go
@@ -6,7 +6,6 @@ package cache
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
@@ -49,7 +48,7 @@ func initDefaultCache() {
 	}
 	if _, err := os.Stat(filepath.Join(dir, "README")); err != nil {
 		// Best effort.
-		ioutil.WriteFile(filepath.Join(dir, "README"), []byte(cacheREADME), 0666)
+		os.WriteFile(filepath.Join(dir, "README"), []byte(cacheREADME), 0666)
 	}
 
 	c, err := Open(dir)
diff --git a/src/cmd/go/internal/cache/hash_test.go b/src/cmd/go/internal/cache/hash_test.go
index 3bf7143039..a0356771ca 100644
--- a/src/cmd/go/internal/cache/hash_test.go
+++ b/src/cmd/go/internal/cache/hash_test.go
@@ -6,7 +6,6 @@ package cache
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -28,7 +27,7 @@ func TestHash(t *testing.T) {
 }
 
 func TestHashFile(t *testing.T) {
-	f, err := ioutil.TempFile("", "cmd-go-test-")
+	f, err := os.CreateTemp("", "cmd-go-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/cfg/cfg.go b/src/cmd/go/internal/cfg/cfg.go
index 9bc48132ae..c48904eacc 100644
--- a/src/cmd/go/internal/cfg/cfg.go
+++ b/src/cmd/go/internal/cfg/cfg.go
@@ -12,7 +12,6 @@ import (
 	"go/build"
 	"internal/cfg"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -187,7 +186,7 @@ func initEnvCache() {
 	if file == "" {
 		return
 	}
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return
 	}
diff --git a/src/cmd/go/internal/envcmd/env.go b/src/cmd/go/internal/envcmd/env.go
index 46af36eb11..6937187522 100644
--- a/src/cmd/go/internal/envcmd/env.go
+++ b/src/cmd/go/internal/envcmd/env.go
@@ -10,7 +10,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"go/build"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -452,7 +451,7 @@ func updateEnvFile(add map[string]string, del map[string]bool) {
 	if file == "" {
 		base.Fatalf("go env: cannot find go env config: %v", err)
 	}
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil && (!os.IsNotExist(err) || len(add) == 0) {
 		base.Fatalf("go env: reading go env config: %v", err)
 	}
@@ -506,11 +505,11 @@ func updateEnvFile(add map[string]string, del map[string]bool) {
 	}
 
 	data = []byte(strings.Join(lines, ""))
-	err = ioutil.WriteFile(file, data, 0666)
+	err = os.WriteFile(file, data, 0666)
 	if err != nil {
 		// Try creating directory.
 		os.MkdirAll(filepath.Dir(file), 0777)
-		err = ioutil.WriteFile(file, data, 0666)
+		err = os.WriteFile(file, data, 0666)
 		if err != nil {
 			base.Fatalf("go env: writing go env config: %v", err)
 		}
diff --git a/src/cmd/go/internal/fsys/fsys.go b/src/cmd/go/internal/fsys/fsys.go
index 0264786e5b..7b06c3c7f3 100644
--- a/src/cmd/go/internal/fsys/fsys.go
+++ b/src/cmd/go/internal/fsys/fsys.go
@@ -86,7 +86,7 @@ func Init(wd string) error {
 		return nil
 	}
 
-	b, err := ioutil.ReadFile(OverlayFile)
+	b, err := os.ReadFile(OverlayFile)
 	if err != nil {
 		return fmt.Errorf("reading overlay file: %v", err)
 	}
diff --git a/src/cmd/go/internal/fsys/fsys_test.go b/src/cmd/go/internal/fsys/fsys_test.go
index 90a69de14a..7f175c7031 100644
--- a/src/cmd/go/internal/fsys/fsys_test.go
+++ b/src/cmd/go/internal/fsys/fsys_test.go
@@ -8,7 +8,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -47,7 +46,7 @@ func initOverlay(t *testing.T, config string) {
 		if err := os.MkdirAll(filepath.Dir(name), 0777); err != nil {
 			t.Fatal(err)
 		}
-		if err := ioutil.WriteFile(name, f.Data, 0666); err != nil {
+		if err := os.WriteFile(name, f.Data, 0666); err != nil {
 			t.Fatal(err)
 		}
 	}
diff --git a/src/cmd/go/internal/generate/generate.go b/src/cmd/go/internal/generate/generate.go
index 98c17bba8c..c7401948b8 100644
--- a/src/cmd/go/internal/generate/generate.go
+++ b/src/cmd/go/internal/generate/generate.go
@@ -13,7 +13,6 @@ import (
 	"go/parser"
 	"go/token"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -201,7 +200,7 @@ func runGenerate(ctx context.Context, cmd *base.Command, args []string) {
 
 // generate runs the generation directives for a single file.
 func generate(absFile string) bool {
-	src, err := ioutil.ReadFile(absFile)
+	src, err := os.ReadFile(absFile)
 	if err != nil {
 		log.Fatalf("generate: %s", err)
 	}
diff --git a/src/cmd/go/internal/imports/scan_test.go b/src/cmd/go/internal/imports/scan_test.go
index e424656cae..5ba3201968 100644
--- a/src/cmd/go/internal/imports/scan_test.go
+++ b/src/cmd/go/internal/imports/scan_test.go
@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"internal/testenv"
 	"io/ioutil"
+	"os"
 	"path"
 	"path/filepath"
 	"runtime"
@@ -66,7 +67,7 @@ func TestScanDir(t *testing.T) {
 			continue
 		}
 		t.Run(dir.Name(), func(t *testing.T) {
-			tagsData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "tags.txt"))
+			tagsData, err := os.ReadFile(filepath.Join("testdata", dir.Name(), "tags.txt"))
 			if err != nil {
 				t.Fatalf("error reading tags: %v", err)
 			}
@@ -75,7 +76,7 @@ func TestScanDir(t *testing.T) {
 				tags[t] = true
 			}
 
-			wantData, err := ioutil.ReadFile(filepath.Join("testdata", dir.Name(), "want.txt"))
+			wantData, err := os.ReadFile(filepath.Join("testdata", dir.Name(), "want.txt"))
 			if err != nil {
 				t.Fatalf("error reading want: %v", err)
 			}
diff --git a/src/cmd/go/internal/load/pkg.go b/src/cmd/go/internal/load/pkg.go
index cbc683da2b..da3e0b895c 100644
--- a/src/cmd/go/internal/load/pkg.go
+++ b/src/cmd/go/internal/load/pkg.go
@@ -1147,7 +1147,7 @@ var (
 // goModPath returns the module path in the go.mod in dir, if any.
 func goModPath(dir string) (path string) {
 	return goModPathCache.Do(dir, func() interface{} {
-		data, err := ioutil.ReadFile(filepath.Join(dir, "go.mod"))
+		data, err := os.ReadFile(filepath.Join(dir, "go.mod"))
 		if err != nil {
 			return ""
 		}
@@ -1728,7 +1728,7 @@ func (p *Package) load(ctx context.Context, path string, stk *ImportStack, impor
 			// not work for any package that lacks a Target — such as a non-main
 			// package in module mode. We should probably fix that.
 			shlibnamefile := p.Target[:len(p.Target)-2] + ".shlibname"
-			shlib, err := ioutil.ReadFile(shlibnamefile)
+			shlib, err := os.ReadFile(shlibnamefile)
 			if err != nil && !os.IsNotExist(err) {
 				base.Fatalf("reading shlibname: %v", err)
 			}
diff --git a/src/cmd/go/internal/lockedfile/internal/filelock/filelock_test.go b/src/cmd/go/internal/lockedfile/internal/filelock/filelock_test.go
index 8301fb6b6e..2ac2052b8f 100644
--- a/src/cmd/go/internal/lockedfile/internal/filelock/filelock_test.go
+++ b/src/cmd/go/internal/lockedfile/internal/filelock/filelock_test.go
@@ -9,7 +9,6 @@ package filelock_test
 import (
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -51,9 +50,9 @@ func mustTempFile(t *testing.T) (f *os.File, remove func()) {
 	t.Helper()
 
 	base := filepath.Base(t.Name())
-	f, err := ioutil.TempFile("", base)
+	f, err := os.CreateTemp("", base)
 	if err != nil {
-		t.Fatalf(`ioutil.TempFile("", %q) = %v`, base, err)
+		t.Fatalf(`os.CreateTemp("", %q) = %v`, base, err)
 	}
 	t.Logf("fd %d = %s", f.Fd(), f.Name())
 
diff --git a/src/cmd/go/internal/lockedfile/lockedfile_test.go b/src/cmd/go/internal/lockedfile/lockedfile_test.go
index 416c69d83b..34327dd841 100644
--- a/src/cmd/go/internal/lockedfile/lockedfile_test.go
+++ b/src/cmd/go/internal/lockedfile/lockedfile_test.go
@@ -10,7 +10,6 @@ package lockedfile_test
 import (
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -23,7 +22,7 @@ import (
 func mustTempDir(t *testing.T) (dir string, remove func()) {
 	t.Helper()
 
-	dir, err := ioutil.TempDir("", filepath.Base(t.Name()))
+	dir, err := os.MkdirTemp("", filepath.Base(t.Name()))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -155,8 +154,8 @@ func TestCanLockExistingFile(t *testing.T) {
 	defer remove()
 	path := filepath.Join(dir, "existing.txt")
 
-	if err := ioutil.WriteFile(path, []byte("ok"), 0777); err != nil {
-		t.Fatalf("ioutil.WriteFile: %v", err)
+	if err := os.WriteFile(path, []byte("ok"), 0777); err != nil {
+		t.Fatalf("os.WriteFile: %v", err)
 	}
 
 	f, err := lockedfile.Edit(path)
@@ -201,7 +200,7 @@ func TestSpuriousEDEADLK(t *testing.T) {
 		}
 		defer b.Close()
 
-		if err := ioutil.WriteFile(filepath.Join(dir, "locked"), []byte("ok"), 0666); err != nil {
+		if err := os.WriteFile(filepath.Join(dir, "locked"), []byte("ok"), 0666); err != nil {
 			t.Fatal(err)
 		}
 
diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index 38c473d36b..390a195547 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -155,7 +155,7 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go mod vendor: %v", err)
 	}
 
-	if err := ioutil.WriteFile(filepath.Join(vdir, "modules.txt"), buf.Bytes(), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(vdir, "modules.txt"), buf.Bytes(), 0666); err != nil {
 		base.Fatalf("go mod vendor: %v", err)
 	}
 }
diff --git a/src/cmd/go/internal/modcmd/verify.go b/src/cmd/go/internal/modcmd/verify.go
index ce24793929..c83e70076a 100644
--- a/src/cmd/go/internal/modcmd/verify.go
+++ b/src/cmd/go/internal/modcmd/verify.go
@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"runtime"
 
@@ -87,7 +86,7 @@ func verifyMod(mod module.Version) []error {
 		_, zipErr = os.Stat(zip)
 	}
 	dir, dirErr := modfetch.DownloadDir(mod)
-	data, err := ioutil.ReadFile(zip + "hash")
+	data, err := os.ReadFile(zip + "hash")
 	if err != nil {
 		if zipErr != nil && errors.Is(zipErr, fs.ErrNotExist) &&
 			dirErr != nil && errors.Is(dirErr, fs.ErrNotExist) {
diff --git a/src/cmd/go/internal/modconv/convert_test.go b/src/cmd/go/internal/modconv/convert_test.go
index faa2b4c606..66b9ff4f38 100644
--- a/src/cmd/go/internal/modconv/convert_test.go
+++ b/src/cmd/go/internal/modconv/convert_test.go
@@ -9,7 +9,6 @@ import (
 	"context"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -37,7 +36,7 @@ func testMain(m *testing.M) int {
 		return 0
 	}
 
-	dir, err := ioutil.TempDir("", "modconv-test-")
+	dir, err := os.MkdirTemp("", "modconv-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -167,7 +166,7 @@ func TestConvertLegacyConfig(t *testing.T) {
 
 			for name := range Converters {
 				file := filepath.Join(dir, name)
-				data, err := ioutil.ReadFile(file)
+				data, err := os.ReadFile(file)
 				if err == nil {
 					f := new(modfile.File)
 					f.AddModuleStmt(tt.path)
diff --git a/src/cmd/go/internal/modconv/modconv_test.go b/src/cmd/go/internal/modconv/modconv_test.go
index ccc4f3d576..750525d404 100644
--- a/src/cmd/go/internal/modconv/modconv_test.go
+++ b/src/cmd/go/internal/modconv/modconv_test.go
@@ -7,7 +7,7 @@ package modconv
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 )
@@ -42,7 +42,7 @@ func Test(t *testing.T) {
 			if Converters[extMap[ext]] == nil {
 				t.Fatalf("Converters[%q] == nil", extMap[ext])
 			}
-			data, err := ioutil.ReadFile(test)
+			data, err := os.ReadFile(test)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -50,7 +50,7 @@ func Test(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			want, err := ioutil.ReadFile(test[:len(test)-len(ext)] + ".out")
+			want, err := os.ReadFile(test[:len(test)-len(ext)] + ".out")
 			if err != nil {
 				t.Error(err)
 			}
diff --git a/src/cmd/go/internal/modfetch/cache_test.go b/src/cmd/go/internal/modfetch/cache_test.go
index 241c800e69..722c984e37 100644
--- a/src/cmd/go/internal/modfetch/cache_test.go
+++ b/src/cmd/go/internal/modfetch/cache_test.go
@@ -5,14 +5,13 @@
 package modfetch
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
 func TestWriteDiskCache(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "go-writeCache-test-")
+	tmpdir, err := os.MkdirTemp("", "go-writeCache-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modfetch/codehost/codehost.go b/src/cmd/go/internal/modfetch/codehost/codehost.go
index 286d3f7220..86c1c14d4a 100644
--- a/src/cmd/go/internal/modfetch/codehost/codehost.go
+++ b/src/cmd/go/internal/modfetch/codehost/codehost.go
@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -189,7 +188,7 @@ func WorkDir(typ, name string) (dir, lockfile string, err error) {
 	}
 	defer unlock()
 
-	data, err := ioutil.ReadFile(dir + ".info")
+	data, err := os.ReadFile(dir + ".info")
 	info, err2 := os.Stat(dir)
 	if err == nil && err2 == nil && info.IsDir() {
 		// Info file and directory both already exist: reuse.
@@ -211,7 +210,7 @@ func WorkDir(typ, name string) (dir, lockfile string, err error) {
 	if err := os.MkdirAll(dir, 0777); err != nil {
 		return "", "", err
 	}
-	if err := ioutil.WriteFile(dir+".info", []byte(key), 0666); err != nil {
+	if err := os.WriteFile(dir+".info", []byte(key), 0666); err != nil {
 		os.RemoveAll(dir)
 		return "", "", err
 	}
diff --git a/src/cmd/go/internal/modfetch/codehost/git_test.go b/src/cmd/go/internal/modfetch/codehost/git_test.go
index 981e3fe91f..89a73baad9 100644
--- a/src/cmd/go/internal/modfetch/codehost/git_test.go
+++ b/src/cmd/go/internal/modfetch/codehost/git_test.go
@@ -12,7 +12,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -54,7 +53,7 @@ func testMain(m *testing.M) int {
 		return 0
 	}
 
-	dir, err := ioutil.TempDir("", "gitrepo-test-")
+	dir, err := os.MkdirTemp("", "gitrepo-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modfetch/codehost/shell.go b/src/cmd/go/internal/modfetch/codehost/shell.go
index b9525adf5e..ce8b501d53 100644
--- a/src/cmd/go/internal/modfetch/codehost/shell.go
+++ b/src/cmd/go/internal/modfetch/codehost/shell.go
@@ -15,7 +15,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"strings"
@@ -124,7 +123,7 @@ func main() {
 			}
 
 			if f[3] != "-" {
-				if err := ioutil.WriteFile(f[3], data, 0666); err != nil {
+				if err := os.WriteFile(f[3], data, 0666); err != nil {
 					fmt.Fprintf(os.Stderr, "?%s\n", err)
 					continue
 				}
diff --git a/src/cmd/go/internal/modfetch/codehost/vcs.go b/src/cmd/go/internal/modfetch/codehost/vcs.go
index e67ee94ad8..c2cca084e3 100644
--- a/src/cmd/go/internal/modfetch/codehost/vcs.go
+++ b/src/cmd/go/internal/modfetch/codehost/vcs.go
@@ -10,7 +10,6 @@ import (
 	"internal/lazyregexp"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -433,7 +432,7 @@ func (r *vcsRepo) ReadZip(rev, subdir string, maxSize int64) (zip io.ReadCloser,
 	if rev == "latest" {
 		rev = r.cmd.latest
 	}
-	f, err := ioutil.TempFile("", "go-readzip-*.zip")
+	f, err := os.CreateTemp("", "go-readzip-*.zip")
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/cmd/go/internal/modfetch/coderepo.go b/src/cmd/go/internal/modfetch/coderepo.go
index b6bcf83f1a..2dcbb99b18 100644
--- a/src/cmd/go/internal/modfetch/coderepo.go
+++ b/src/cmd/go/internal/modfetch/coderepo.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path"
 	"sort"
@@ -966,7 +965,7 @@ func (r *codeRepo) Zip(dst io.Writer, version string) error {
 	subdir = strings.Trim(subdir, "/")
 
 	// Spool to local file.
-	f, err := ioutil.TempFile("", "go-codehost-")
+	f, err := os.CreateTemp("", "go-codehost-")
 	if err != nil {
 		dl.Close()
 		return err
diff --git a/src/cmd/go/internal/modfetch/coderepo_test.go b/src/cmd/go/internal/modfetch/coderepo_test.go
index 53b048dbdf..02e399f352 100644
--- a/src/cmd/go/internal/modfetch/coderepo_test.go
+++ b/src/cmd/go/internal/modfetch/coderepo_test.go
@@ -11,7 +11,6 @@ import (
 	"hash"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"reflect"
@@ -38,7 +37,7 @@ func testMain(m *testing.M) int {
 	// code, bypass the sum database.
 	cfg.GOSUMDB = "off"
 
-	dir, err := ioutil.TempDir("", "gitrepo-test-")
+	dir, err := os.MkdirTemp("", "gitrepo-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -424,7 +423,7 @@ var codeRepoTests = []codeRepoTest{
 func TestCodeRepo(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 
-	tmpdir, err := ioutil.TempDir("", "modfetch-test-")
+	tmpdir, err := os.MkdirTemp("", "modfetch-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -491,9 +490,9 @@ func TestCodeRepo(t *testing.T) {
 
 					needHash := !testing.Short() && (tt.zipFileHash != "" || tt.zipSum != "")
 					if tt.zip != nil || tt.zipErr != "" || needHash {
-						f, err := ioutil.TempFile(tmpdir, tt.version+".zip.")
+						f, err := os.CreateTemp(tmpdir, tt.version+".zip.")
 						if err != nil {
-							t.Fatalf("ioutil.TempFile: %v", err)
+							t.Fatalf("os.CreateTemp: %v", err)
 						}
 						zipfile := f.Name()
 						defer func() {
@@ -655,7 +654,7 @@ var codeRepoVersionsTests = []struct {
 func TestCodeRepoVersions(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 
-	tmpdir, err := ioutil.TempDir("", "vgo-modfetch-test-")
+	tmpdir, err := os.MkdirTemp("", "vgo-modfetch-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -729,7 +728,7 @@ var latestTests = []struct {
 func TestLatest(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 
-	tmpdir, err := ioutil.TempDir("", "vgo-modfetch-test-")
+	tmpdir, err := os.MkdirTemp("", "vgo-modfetch-test-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modfetch/fetch.go b/src/cmd/go/internal/modfetch/fetch.go
index 2ee78de5b2..debeb3f319 100644
--- a/src/cmd/go/internal/modfetch/fetch.go
+++ b/src/cmd/go/internal/modfetch/fetch.go
@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -136,7 +135,7 @@ func download(ctx context.Context, mod module.Version) (dir string, err error) {
 	if err := os.MkdirAll(parentDir, 0777); err != nil {
 		return "", err
 	}
-	if err := ioutil.WriteFile(partialPath, nil, 0666); err != nil {
+	if err := os.WriteFile(partialPath, nil, 0666); err != nil {
 		return "", err
 	}
 	if err := modzip.Unzip(dir, mod, zipfile); err != nil {
@@ -223,7 +222,7 @@ func downloadZip(ctx context.Context, mod module.Version, zipfile string) (err e
 	// contents of the file (by hashing it) before we commit it. Because the file
 	// is zip-compressed, we need an actual file — or at least an io.ReaderAt — to
 	// validate it: we can't just tee the stream as we write it.
-	f, err := ioutil.TempFile(filepath.Dir(zipfile), filepath.Base(renameio.Pattern(zipfile)))
+	f, err := os.CreateTemp(filepath.Dir(zipfile), filepath.Base(renameio.Pattern(zipfile)))
 	if err != nil {
 		return err
 	}
diff --git a/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go b/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
index 82398ebfed..d9ba8ef2da 100644
--- a/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
+++ b/src/cmd/go/internal/modfetch/zip_sum_test/zip_sum_test.go
@@ -24,7 +24,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -81,7 +80,7 @@ func TestZipSums(t *testing.T) {
 	if *modCacheDir != "" {
 		cfg.BuildContext.GOPATH = *modCacheDir
 	} else {
-		tmpDir, err := ioutil.TempDir("", "TestZipSums")
+		tmpDir, err := os.MkdirTemp("", "TestZipSums")
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 1c31a5f90a..6a2cea668d 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -632,7 +632,7 @@ func setDefaultBuildMod() {
 func convertLegacyConfig(modPath string) (from string, err error) {
 	for _, name := range altConfigs {
 		cfg := filepath.Join(modRoot, name)
-		data, err := ioutil.ReadFile(cfg)
+		data, err := os.ReadFile(cfg)
 		if err == nil {
 			convert := modconv.Converters[name]
 			if convert == nil {
@@ -753,7 +753,7 @@ func findModulePath(dir string) (string, error) {
 	}
 
 	// Look for Godeps.json declaring import path.
-	data, _ := ioutil.ReadFile(filepath.Join(dir, "Godeps/Godeps.json"))
+	data, _ := os.ReadFile(filepath.Join(dir, "Godeps/Godeps.json"))
 	var cfg1 struct{ ImportPath string }
 	json.Unmarshal(data, &cfg1)
 	if cfg1.ImportPath != "" {
@@ -761,7 +761,7 @@ func findModulePath(dir string) (string, error) {
 	}
 
 	// Look for vendor.json declaring import path.
-	data, _ = ioutil.ReadFile(filepath.Join(dir, "vendor/vendor.json"))
+	data, _ = os.ReadFile(filepath.Join(dir, "vendor/vendor.json"))
 	var cfg2 struct{ RootPath string }
 	json.Unmarshal(data, &cfg2)
 	if cfg2.RootPath != "" {
@@ -813,7 +813,7 @@ var (
 )
 
 func findImportComment(file string) string {
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return ""
 	}
diff --git a/src/cmd/go/internal/modload/query_test.go b/src/cmd/go/internal/modload/query_test.go
index 777a56b977..e225a0e71e 100644
--- a/src/cmd/go/internal/modload/query_test.go
+++ b/src/cmd/go/internal/modload/query_test.go
@@ -7,7 +7,6 @@ package modload
 import (
 	"context"
 	"internal/testenv"
-	"io/ioutil"
 	"log"
 	"os"
 	"path"
@@ -27,7 +26,7 @@ func TestMain(m *testing.M) {
 func testMain(m *testing.M) int {
 	cfg.GOPROXY = "direct"
 
-	dir, err := ioutil.TempDir("", "modload-test-")
+	dir, err := os.MkdirTemp("", "modload-test-")
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/modload/vendor.go b/src/cmd/go/internal/modload/vendor.go
index ab29d4d014..80d49053c6 100644
--- a/src/cmd/go/internal/modload/vendor.go
+++ b/src/cmd/go/internal/modload/vendor.go
@@ -8,7 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strings"
 	"sync"
@@ -40,7 +40,7 @@ func readVendorList() {
 		vendorPkgModule = make(map[string]module.Version)
 		vendorVersion = make(map[string]string)
 		vendorMeta = make(map[module.Version]vendorMetadata)
-		data, err := ioutil.ReadFile(filepath.Join(ModRoot(), "vendor/modules.txt"))
+		data, err := os.ReadFile(filepath.Join(ModRoot(), "vendor/modules.txt"))
 		if err != nil {
 			if !errors.Is(err, fs.ErrNotExist) {
 				base.Fatalf("go: %s", err)
diff --git a/src/cmd/go/internal/renameio/renameio.go b/src/cmd/go/internal/renameio/renameio.go
index 60a7138a76..9788171d6e 100644
--- a/src/cmd/go/internal/renameio/renameio.go
+++ b/src/cmd/go/internal/renameio/renameio.go
@@ -25,7 +25,7 @@ func Pattern(filename string) string {
 	return filepath.Join(filepath.Dir(filename), filepath.Base(filename)+patternSuffix)
 }
 
-// WriteFile is like ioutil.WriteFile, but first writes data to an arbitrary
+// WriteFile is like os.WriteFile, but first writes data to an arbitrary
 // file in the same directory as filename, then renames it atomically to the
 // final name.
 //
@@ -67,7 +67,7 @@ func WriteToFile(filename string, data io.Reader, perm fs.FileMode) (err error)
 	return robustio.Rename(f.Name(), filename)
 }
 
-// ReadFile is like ioutil.ReadFile, but on Windows retries spurious errors that
+// ReadFile is like os.ReadFile, but on Windows retries spurious errors that
 // may occur if the file is concurrently replaced.
 //
 // Errors are classified heuristically and retries are bounded, so even this
diff --git a/src/cmd/go/internal/renameio/renameio_test.go b/src/cmd/go/internal/renameio/renameio_test.go
index e6d2025a0e..5b2ed83624 100644
--- a/src/cmd/go/internal/renameio/renameio_test.go
+++ b/src/cmd/go/internal/renameio/renameio_test.go
@@ -10,7 +10,6 @@ import (
 	"encoding/binary"
 	"errors"
 	"internal/testenv"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"path/filepath"
@@ -30,7 +29,7 @@ func TestConcurrentReadsAndWrites(t *testing.T) {
 		testenv.SkipFlaky(t, 33041)
 	}
 
-	dir, err := ioutil.TempDir("", "renameio")
+	dir, err := os.MkdirTemp("", "renameio")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/renameio/umask_test.go b/src/cmd/go/internal/renameio/umask_test.go
index 19e217c548..65e4fa587b 100644
--- a/src/cmd/go/internal/renameio/umask_test.go
+++ b/src/cmd/go/internal/renameio/umask_test.go
@@ -8,7 +8,6 @@ package renameio
 
 import (
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -16,7 +15,7 @@ import (
 )
 
 func TestWriteFileModeAppliesUmask(t *testing.T) {
-	dir, err := ioutil.TempDir("", "renameio")
+	dir, err := os.MkdirTemp("", "renameio")
 	if err != nil {
 		t.Fatalf("Failed to create temporary directory: %v", err)
 	}
diff --git a/src/cmd/go/internal/robustio/robustio.go b/src/cmd/go/internal/robustio/robustio.go
index 76e47ad1ff..ce3dbbde6d 100644
--- a/src/cmd/go/internal/robustio/robustio.go
+++ b/src/cmd/go/internal/robustio/robustio.go
@@ -22,7 +22,7 @@ func Rename(oldpath, newpath string) error {
 	return rename(oldpath, newpath)
 }
 
-// ReadFile is like ioutil.ReadFile, but on Windows retries errors that may
+// ReadFile is like os.ReadFile, but on Windows retries errors that may
 // occur if the file is concurrently replaced.
 //
 // (See golang.org/issue/31247 and golang.org/issue/32188.)
diff --git a/src/cmd/go/internal/robustio/robustio_flaky.go b/src/cmd/go/internal/robustio/robustio_flaky.go
index d4cb7e6457..5bd44bd345 100644
--- a/src/cmd/go/internal/robustio/robustio_flaky.go
+++ b/src/cmd/go/internal/robustio/robustio_flaky.go
@@ -8,7 +8,6 @@ package robustio
 
 import (
 	"errors"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"syscall"
@@ -70,11 +69,11 @@ func rename(oldpath, newpath string) (err error) {
 	})
 }
 
-// readFile is like ioutil.ReadFile, but retries ephemeral errors.
+// readFile is like os.ReadFile, but retries ephemeral errors.
 func readFile(filename string) ([]byte, error) {
 	var b []byte
 	err := retry(func() (err error, mayRetry bool) {
-		b, err = ioutil.ReadFile(filename)
+		b, err = os.ReadFile(filename)
 
 		// Unlike in rename, we do not retry errFileNotFound here: it can occur
 		// as a spurious error, but the file may also genuinely not exist, so the
diff --git a/src/cmd/go/internal/robustio/robustio_other.go b/src/cmd/go/internal/robustio/robustio_other.go
index 907b556858..6fe7b7e4e4 100644
--- a/src/cmd/go/internal/robustio/robustio_other.go
+++ b/src/cmd/go/internal/robustio/robustio_other.go
@@ -7,7 +7,6 @@
 package robustio
 
 import (
-	"io/ioutil"
 	"os"
 )
 
@@ -16,7 +15,7 @@ func rename(oldpath, newpath string) error {
 }
 
 func readFile(filename string) ([]byte, error) {
-	return ioutil.ReadFile(filename)
+	return os.ReadFile(filename)
 }
 
 func removeAll(path string) error {
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 24601dc061..401b67c260 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -884,7 +884,7 @@ func builderTest(b *work.Builder, ctx context.Context, p *load.Package) (buildAc
 	if !cfg.BuildN {
 		// writeTestmain writes _testmain.go,
 		// using the test description gathered in t.
-		if err := ioutil.WriteFile(testDir+"_testmain.go", *pmain.Internal.TestmainGo, 0666); err != nil {
+		if err := os.WriteFile(testDir+"_testmain.go", *pmain.Internal.TestmainGo, 0666); err != nil {
 			return nil, nil, nil, err
 		}
 	}
@@ -1616,7 +1616,7 @@ func (c *runCache) saveOutput(a *work.Action) {
 	}
 
 	// See comment about two-level lookup in tryCacheWithID above.
-	testlog, err := ioutil.ReadFile(a.Objdir + "testlog.txt")
+	testlog, err := os.ReadFile(a.Objdir + "testlog.txt")
 	if err != nil || !bytes.HasPrefix(testlog, testlogMagic) || testlog[len(testlog)-1] != '\n' {
 		if cache.DebugTest {
 			if err != nil {
diff --git a/src/cmd/go/internal/txtar/archive.go b/src/cmd/go/internal/txtar/archive.go
index c384f33bdf..1796684877 100644
--- a/src/cmd/go/internal/txtar/archive.go
+++ b/src/cmd/go/internal/txtar/archive.go
@@ -34,7 +34,7 @@ package txtar
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strings"
 )
 
@@ -66,7 +66,7 @@ func Format(a *Archive) []byte {
 
 // ParseFile parses the named file as an archive.
 func ParseFile(file string) (*Archive, error) {
-	data, err := ioutil.ReadFile(file)
+	data, err := os.ReadFile(file)
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/cmd/go/internal/vcs/vcs_test.go b/src/cmd/go/internal/vcs/vcs_test.go
index 72d74a01e3..c5c7a3283b 100644
--- a/src/cmd/go/internal/vcs/vcs_test.go
+++ b/src/cmd/go/internal/vcs/vcs_test.go
@@ -7,7 +7,6 @@ package vcs
 import (
 	"errors"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
@@ -208,7 +207,7 @@ func TestRepoRootForImportPath(t *testing.T) {
 
 // Test that vcsFromDir correctly inspects a given directory and returns the right VCS and root.
 func TestFromDir(t *testing.T) {
-	tempDir, err := ioutil.TempDir("", "vcstest")
+	tempDir, err := os.MkdirTemp("", "vcstest")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/web/file_test.go b/src/cmd/go/internal/web/file_test.go
index a1bb080e07..3734df5c4e 100644
--- a/src/cmd/go/internal/web/file_test.go
+++ b/src/cmd/go/internal/web/file_test.go
@@ -7,7 +7,6 @@ package web
 import (
 	"errors"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -16,7 +15,7 @@ import (
 func TestGetFileURL(t *testing.T) {
 	const content = "Hello, file!\n"
 
-	f, err := ioutil.TempFile("", "web-TestGetFileURL")
+	f, err := os.CreateTemp("", "web-TestGetFileURL")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index f461c5780f..9d141ae233 100644
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -14,7 +14,6 @@ import (
 	"debug/elf"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -253,7 +252,7 @@ func (b *Builder) Init() {
 	if cfg.BuildN {
 		b.WorkDir = "$WORK"
 	} else {
-		tmp, err := ioutil.TempDir(cfg.Getenv("GOTMPDIR"), "go-build")
+		tmp, err := os.MkdirTemp(cfg.Getenv("GOTMPDIR"), "go-build")
 		if err != nil {
 			base.Fatalf("go: creating work dir: %v", err)
 		}
diff --git a/src/cmd/go/internal/work/build_test.go b/src/cmd/go/internal/work/build_test.go
index e941729734..eaf2639e9e 100644
--- a/src/cmd/go/internal/work/build_test.go
+++ b/src/cmd/go/internal/work/build_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -170,7 +169,7 @@ func TestSharedLibName(t *testing.T) {
 	for _, data := range testData {
 		func() {
 			if data.rootedAt != "" {
-				tmpGopath, err := ioutil.TempDir("", "gopath")
+				tmpGopath, err := os.MkdirTemp("", "gopath")
 				if err != nil {
 					t.Fatal(err)
 				}
@@ -238,7 +237,7 @@ func TestRespectSetgidDir(t *testing.T) {
 		return cmdBuf.WriteString(fmt.Sprint(a...))
 	}
 
-	setgiddir, err := ioutil.TempDir("", "SetGroupID")
+	setgiddir, err := os.MkdirTemp("", "SetGroupID")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -258,9 +257,9 @@ func TestRespectSetgidDir(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	pkgfile, err := ioutil.TempFile("", "pkgfile")
+	pkgfile, err := os.CreateTemp("", "pkgfile")
 	if err != nil {
-		t.Fatalf("ioutil.TempFile(\"\", \"pkgfile\"): %v", err)
+		t.Fatalf("os.CreateTemp(\"\", \"pkgfile\"): %v", err)
 	}
 	defer os.Remove(pkgfile.Name())
 	defer pkgfile.Close()
diff --git a/src/cmd/go/internal/work/buildid.go b/src/cmd/go/internal/work/buildid.go
index 3c7be5a3e3..d76988145b 100644
--- a/src/cmd/go/internal/work/buildid.go
+++ b/src/cmd/go/internal/work/buildid.go
@@ -7,7 +7,6 @@ package work
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
@@ -344,7 +343,7 @@ func (b *Builder) gccgoBuildIDFile(a *Action) (string, error) {
 		}
 	}
 
-	if err := ioutil.WriteFile(sfile, buf.Bytes(), 0666); err != nil {
+	if err := os.WriteFile(sfile, buf.Bytes(), 0666); err != nil {
 		return "", err
 	}
 
diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 6ce56dd6f4..336751df27 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -16,7 +16,6 @@ import (
 	"internal/lazyregexp"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"math/rand"
 	"os"
@@ -94,7 +93,7 @@ func (b *Builder) Do(ctx context.Context, root *Action) {
 				base.Fatalf("go: refusing to write action graph to %v\n", file)
 			}
 			js := actionGraphJSON(root)
-			if err := ioutil.WriteFile(file, []byte(js), 0666); err != nil {
+			if err := os.WriteFile(file, []byte(js), 0666); err != nil {
 				fmt.Fprintf(os.Stderr, "go: writing action graph: %v\n", err)
 				base.SetExitStatus(1)
 			}
@@ -636,7 +635,7 @@ OverlayLoop:
 			sfiles, gccfiles = filter(sfiles, sfiles[:0], gccfiles)
 		} else {
 			for _, sfile := range sfiles {
-				data, err := ioutil.ReadFile(filepath.Join(a.Package.Dir, sfile))
+				data, err := os.ReadFile(filepath.Join(a.Package.Dir, sfile))
 				if err == nil {
 					if bytes.HasPrefix(data, []byte("TEXT")) || bytes.Contains(data, []byte("\nTEXT")) ||
 						bytes.HasPrefix(data, []byte("DATA")) || bytes.Contains(data, []byte("\nDATA")) ||
@@ -1471,7 +1470,7 @@ func (b *Builder) installShlibname(ctx context.Context, a *Action) error {
 
 	// TODO: BuildN
 	a1 := a.Deps[0]
-	err := ioutil.WriteFile(a.Target, []byte(filepath.Base(a1.Target)+"\n"), 0666)
+	err := os.WriteFile(a.Target, []byte(filepath.Base(a1.Target)+"\n"), 0666)
 	if err != nil {
 		return err
 	}
@@ -1788,7 +1787,7 @@ func (b *Builder) writeFile(file string, text []byte) error {
 	if cfg.BuildN {
 		return nil
 	}
-	return ioutil.WriteFile(file, text, 0666)
+	return os.WriteFile(file, text, 0666)
 }
 
 // Install the cgo export header file, if there is one.
@@ -2537,7 +2536,7 @@ func (b *Builder) gccSupportsFlag(compiler []string, flag string) bool {
 
 	tmp := os.DevNull
 	if runtime.GOOS == "windows" {
-		f, err := ioutil.TempFile(b.WorkDir, "")
+		f, err := os.CreateTemp(b.WorkDir, "")
 		if err != nil {
 			return false
 		}
@@ -2840,7 +2839,7 @@ func (b *Builder) cgo(a *Action, cgoExe, objdir string, pcCFLAGS, pcLDFLAGS, cgo
 				continue
 			}
 
-			src, err := ioutil.ReadFile(f)
+			src, err := os.ReadFile(f)
 			if err != nil {
 				return nil, nil, err
 			}
@@ -3070,7 +3069,7 @@ func (b *Builder) swigDoIntSize(objdir string) (intsize string, err error) {
 		return "$INTBITS", nil
 	}
 	src := filepath.Join(b.WorkDir, "swig_intsize.go")
-	if err = ioutil.WriteFile(src, []byte(swigIntSizeCode), 0666); err != nil {
+	if err = os.WriteFile(src, []byte(swigIntSizeCode), 0666); err != nil {
 		return
 	}
 	srcs := []string{src}
@@ -3230,7 +3229,7 @@ func passLongArgsInResponseFiles(cmd *exec.Cmd) (cleanup func()) {
 		return
 	}
 
-	tf, err := ioutil.TempFile("", "args")
+	tf, err := os.CreateTemp("", "args")
 	if err != nil {
 		log.Fatalf("error writing long arguments to response file: %v", err)
 	}
diff --git a/src/cmd/go/internal/work/gc.go b/src/cmd/go/internal/work/gc.go
index 3a53c714e3..cc4e2b2b2b 100644
--- a/src/cmd/go/internal/work/gc.go
+++ b/src/cmd/go/internal/work/gc.go
@@ -9,7 +9,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -426,11 +425,11 @@ func toolVerify(a *Action, b *Builder, p *load.Package, newTool string, ofile st
 	if err := b.run(a, p.Dir, p.ImportPath, nil, newArgs...); err != nil {
 		return err
 	}
-	data1, err := ioutil.ReadFile(ofile)
+	data1, err := os.ReadFile(ofile)
 	if err != nil {
 		return err
 	}
-	data2, err := ioutil.ReadFile(ofile + ".new")
+	data2, err := os.ReadFile(ofile + ".new")
 	if err != nil {
 		return err
 	}
@@ -580,7 +579,7 @@ func pluginPath(a *Action) string {
 	}
 	fmt.Fprintf(h, "build ID: %s\n", buildID)
 	for _, file := range str.StringList(p.GoFiles, p.CgoFiles, p.SFiles) {
-		data, err := ioutil.ReadFile(filepath.Join(p.Dir, file))
+		data, err := os.ReadFile(filepath.Join(p.Dir, file))
 		if err != nil {
 			base.Fatalf("go: %s", err)
 		}
diff --git a/src/cmd/go/internal/work/gccgo.go b/src/cmd/go/internal/work/gccgo.go
index 01d2b89159..3ffd01c473 100644
--- a/src/cmd/go/internal/work/gccgo.go
+++ b/src/cmd/go/internal/work/gccgo.go
@@ -6,7 +6,6 @@ package work
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -271,7 +270,7 @@ func (tools gccgoToolchain) link(b *Builder, root *Action, out, importcfg string
 	}
 
 	readCgoFlags := func(flagsFile string) error {
-		flags, err := ioutil.ReadFile(flagsFile)
+		flags, err := os.ReadFile(flagsFile)
 		if err != nil {
 			return err
 		}
diff --git a/src/cmd/go/script_test.go b/src/cmd/go/script_test.go
index aee3742f13..dfaa40548e 100644
--- a/src/cmd/go/script_test.go
+++ b/src/cmd/go/script_test.go
@@ -15,7 +15,6 @@ import (
 	"go/build"
 	"internal/testenv"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -220,7 +219,7 @@ func (ts *testScript) run() {
 	for _, f := range a.Files {
 		name := ts.mkabs(ts.expand(f.Name, false))
 		ts.check(os.MkdirAll(filepath.Dir(name), 0777))
-		ts.check(ioutil.WriteFile(name, f.Data, 0666))
+		ts.check(os.WriteFile(name, f.Data, 0666))
 	}
 
 	// With -v or -testwork, start log with full environment.
@@ -377,19 +376,19 @@ var (
 
 func isCaseSensitive(t *testing.T) bool {
 	onceCaseSensitive.Do(func() {
-		tmpdir, err := ioutil.TempDir("", "case-sensitive")
+		tmpdir, err := os.MkdirTemp("", "case-sensitive")
 		if err != nil {
 			t.Fatal("failed to create directory to determine case-sensitivity:", err)
 		}
 		defer os.RemoveAll(tmpdir)
 
 		fcap := filepath.Join(tmpdir, "FILE")
-		if err := ioutil.WriteFile(fcap, []byte{}, 0644); err != nil {
+		if err := os.WriteFile(fcap, []byte{}, 0644); err != nil {
 			t.Fatal("error writing file to determine case-sensitivity:", err)
 		}
 
 		flow := filepath.Join(tmpdir, "file")
-		_, err = ioutil.ReadFile(flow)
+		_, err = os.ReadFile(flow)
 		switch {
 		case err == nil:
 			caseSensitive = false
@@ -450,9 +449,9 @@ func (ts *testScript) cmdAddcrlf(want simpleStatus, args []string) {
 
 	for _, file := range args {
 		file = ts.mkabs(file)
-		data, err := ioutil.ReadFile(file)
+		data, err := os.ReadFile(file)
 		ts.check(err)
-		ts.check(ioutil.WriteFile(file, bytes.ReplaceAll(data, []byte("\n"), []byte("\r\n")), 0666))
+		ts.check(os.WriteFile(file, bytes.ReplaceAll(data, []byte("\n"), []byte("\r\n")), 0666))
 	}
 }
 
@@ -557,12 +556,12 @@ func (ts *testScript) doCmdCmp(args []string, env, quiet bool) {
 	} else if name1 == "stderr" {
 		text1 = ts.stderr
 	} else {
-		data, err := ioutil.ReadFile(ts.mkabs(name1))
+		data, err := os.ReadFile(ts.mkabs(name1))
 		ts.check(err)
 		text1 = string(data)
 	}
 
-	data, err := ioutil.ReadFile(ts.mkabs(name2))
+	data, err := os.ReadFile(ts.mkabs(name2))
 	ts.check(err)
 	text2 = string(data)
 
@@ -614,14 +613,14 @@ func (ts *testScript) cmdCp(want simpleStatus, args []string) {
 			info, err := os.Stat(src)
 			ts.check(err)
 			mode = info.Mode() & 0777
-			data, err = ioutil.ReadFile(src)
+			data, err = os.ReadFile(src)
 			ts.check(err)
 		}
 		targ := dst
 		if dstDir {
 			targ = filepath.Join(dst, filepath.Base(src))
 		}
-		err := ioutil.WriteFile(targ, data, mode)
+		err := os.WriteFile(targ, data, mode)
 		switch want {
 		case failure:
 			if err == nil {
@@ -897,7 +896,7 @@ func scriptMatch(ts *testScript, want simpleStatus, args []string, text, name st
 	isGrep := name == "grep"
 	if isGrep {
 		name = args[1] // for error messages
-		data, err := ioutil.ReadFile(ts.mkabs(args[1]))
+		data, err := os.ReadFile(ts.mkabs(args[1]))
 		ts.check(err)
 		text = string(data)
 	}
diff --git a/src/cmd/go/testdata/addmod.go b/src/cmd/go/testdata/addmod.go
index 71ac47fdc1..58376b7ed4 100644
--- a/src/cmd/go/testdata/addmod.go
+++ b/src/cmd/go/testdata/addmod.go
@@ -23,7 +23,6 @@ import (
 	"flag"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -58,7 +57,7 @@ func main() {
 	log.SetFlags(0)
 
 	var err error
-	tmpdir, err = ioutil.TempDir("", "addmod-")
+	tmpdir, err = os.MkdirTemp("", "addmod-")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -82,7 +81,7 @@ func main() {
 
 	exitCode := 0
 	for _, arg := range flag.Args() {
-		if err := ioutil.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module m\n"), 0666); err != nil {
+		if err := os.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module m\n"), 0666); err != nil {
 			fatalf("%v", err)
 		}
 		run(goCmd, "get", "-d", arg)
@@ -98,13 +97,13 @@ func main() {
 			continue
 		}
 		path, vers, dir := f[0], f[1], f[2]
-		mod, err := ioutil.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".mod"))
+		mod, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".mod"))
 		if err != nil {
 			log.Printf("%s: %v", arg, err)
 			exitCode = 1
 			continue
 		}
-		info, err := ioutil.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".info"))
+		info, err := os.ReadFile(filepath.Join(gopath, "pkg/mod/cache/download", path, "@v", vers+".info"))
 		if err != nil {
 			log.Printf("%s: %v", arg, err)
 			exitCode = 1
@@ -128,7 +127,7 @@ func main() {
 			}
 			name := info.Name()
 			if name == "go.mod" || strings.HasSuffix(name, ".go") {
-				data, err := ioutil.ReadFile(path)
+				data, err := os.ReadFile(path)
 				if err != nil {
 					return err
 				}
@@ -144,7 +143,7 @@ func main() {
 
 		data := txtar.Format(a)
 		target := filepath.Join("mod", strings.ReplaceAll(path, "/", "_")+"_"+vers+".txt")
-		if err := ioutil.WriteFile(target, data, 0666); err != nil {
+		if err := os.WriteFile(target, data, 0666); err != nil {
 			log.Printf("%s: %v", arg, err)
 			exitCode = 1
 			continue
diff --git a/src/cmd/go/testdata/savedir.go b/src/cmd/go/testdata/savedir.go
index 75895ee279..d469c31a91 100644
--- a/src/cmd/go/testdata/savedir.go
+++ b/src/cmd/go/testdata/savedir.go
@@ -18,7 +18,6 @@ import (
 	"flag"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -63,7 +62,7 @@ func main() {
 		if !info.Type().IsRegular() {
 			return nil
 		}
-		data, err := ioutil.ReadFile(path)
+		data, err := os.ReadFile(path)
 		if err != nil {
 			log.Fatal(err)
 		}
diff --git a/src/cmd/go/testdata/script/build_issue6480.txt b/src/cmd/go/testdata/script/build_issue6480.txt
index ae99c60d99..cf1e9ea6c2 100644
--- a/src/cmd/go/testdata/script/build_issue6480.txt
+++ b/src/cmd/go/testdata/script/build_issue6480.txt
@@ -81,7 +81,6 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"time"
 )
@@ -100,7 +99,7 @@ func truncateLike(t, p time.Time) time.Time {
 
 func main() {
 	var t1 time.Time
-	b1, err := ioutil.ReadFile(os.Args[1])
+	b1, err := os.ReadFile(os.Args[1])
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
@@ -111,7 +110,7 @@ func main() {
 	}
 
 	var t2 time.Time
-	b2, err := ioutil.ReadFile(os.Args[2])
+	b2, err := os.ReadFile(os.Args[2])
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
diff --git a/src/cmd/go/testdata/script/build_trimpath.txt b/src/cmd/go/testdata/script/build_trimpath.txt
index 2c3bee8fdc..e1ea0a48b2 100644
--- a/src/cmd/go/testdata/script/build_trimpath.txt
+++ b/src/cmd/go/testdata/script/build_trimpath.txt
@@ -121,7 +121,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -131,7 +130,7 @@ import (
 
 func main() {
 	exe := os.Args[1]
-	data, err := ioutil.ReadFile(exe)
+	data, err := os.ReadFile(exe)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/cover_error.txt b/src/cmd/go/testdata/script/cover_error.txt
index 4abdf1137a..583a664237 100644
--- a/src/cmd/go/testdata/script/cover_error.txt
+++ b/src/cmd/go/testdata/script/cover_error.txt
@@ -54,7 +54,6 @@ func Test(t *testing.T) {}
 package main
 
 import (
-	"io/ioutil"
 	"log"
 	"os"
 	"strings"
@@ -62,13 +61,13 @@ import (
 
 func main() {
 	log.SetFlags(0)
-	b, err := ioutil.ReadFile(os.Args[1])
+	b, err := os.ReadFile(os.Args[1])
 	if err != nil {
 		log.Fatal(err)
 	}
 	s := strings.ReplaceAll(string(b), "p.go:4:2:", "p.go:4:")
 	s = strings.ReplaceAll(s, "p1.go:6:2:", "p1.go:6:")
-	ioutil.WriteFile(os.Args[1], []byte(s), 0644)
+	os.WriteFile(os.Args[1], []byte(s), 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/gopath_moved_repo.txt b/src/cmd/go/testdata/script/gopath_moved_repo.txt
index 869980da7c..99d80bff5d 100644
--- a/src/cmd/go/testdata/script/gopath_moved_repo.txt
+++ b/src/cmd/go/testdata/script/gopath_moved_repo.txt
@@ -45,7 +45,6 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
 	"log"
 	"os"
 )
@@ -57,11 +56,11 @@ func main() {
 
 	base := []byte(os.Args[1])
 	path := os.Args[2]
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = ioutil.WriteFile(path, bytes.ReplaceAll(data, base, append(base, "XXX"...)), 0644)
+	err = os.WriteFile(path, bytes.ReplaceAll(data, base, append(base, "XXX"...)), 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/mod_download_concurrent_read.txt b/src/cmd/go/testdata/script/mod_download_concurrent_read.txt
index caf105c6e5..231babd0c0 100644
--- a/src/cmd/go/testdata/script/mod_download_concurrent_read.txt
+++ b/src/cmd/go/testdata/script/mod_download_concurrent_read.txt
@@ -25,7 +25,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -45,7 +44,7 @@ func main() {
 // don't need to clean the cache or synchronize closing files after each
 // iteration.
 func run() (err error) {
-	tmpDir, err := ioutil.TempDir("", "")
+	tmpDir, err := os.MkdirTemp("", "")
 	if err != nil {
 		return err
 	}
diff --git a/src/cmd/go/testdata/script/mod_modinfo.txt b/src/cmd/go/testdata/script/mod_modinfo.txt
index d9e9fdec21..8d77e224a5 100644
--- a/src/cmd/go/testdata/script/mod_modinfo.txt
+++ b/src/cmd/go/testdata/script/mod_modinfo.txt
@@ -69,7 +69,6 @@ package main
 import (
 	"bytes"
 	"encoding/hex"
-	"io/ioutil"
 	"log"
 	"os"
 
@@ -77,7 +76,7 @@ import (
 )
 
 func main() {
-	b, err := ioutil.ReadFile(os.Args[0])
+	b, err := os.ReadFile(os.Args[0])
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/mod_test_cached.txt b/src/cmd/go/testdata/script/mod_test_cached.txt
index ffd573c02a..3da4358fa1 100644
--- a/src/cmd/go/testdata/script/mod_test_cached.txt
+++ b/src/cmd/go/testdata/script/mod_test_cached.txt
@@ -51,26 +51,25 @@ bar
 package foo_test
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
 func TestWriteTmp(t *testing.T) {
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(dir)
-	err = ioutil.WriteFile(filepath.Join(dir, "x"), nil, 0666)
+	err = os.WriteFile(filepath.Join(dir, "x"), nil, 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
 }
 
 func TestReadTestdata(t *testing.T) {
-	_, err := ioutil.ReadFile("testdata/foo.txt")
+	_, err := os.ReadFile("testdata/foo.txt")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/test_compile_tempfile.txt b/src/cmd/go/testdata/script/test_compile_tempfile.txt
index 912410814f..05f721a800 100644
--- a/src/cmd/go/testdata/script/test_compile_tempfile.txt
+++ b/src/cmd/go/testdata/script/test_compile_tempfile.txt
@@ -1,7 +1,7 @@
 [short] skip
 
 # Ensure that the target of 'go build -o' can be an existing, empty file so that
-# its name can be reserved using ioutil.TempFile or the 'mktemp` command.
+# its name can be reserved using os.CreateTemp or the 'mktemp` command.
 
 go build -o empty-file$GOEXE main.go
 
diff --git a/src/cmd/go/testdata/script/test_generated_main.txt b/src/cmd/go/testdata/script/test_generated_main.txt
index 75ffa9cde2..2e991a5797 100644
--- a/src/cmd/go/testdata/script/test_generated_main.txt
+++ b/src/cmd/go/testdata/script/test_generated_main.txt
@@ -12,7 +12,6 @@ package x
 import (
 	"os"
 	"path/filepath"
-	"io/ioutil"
 	"regexp"
 	"testing"
 )
@@ -23,7 +22,7 @@ func Test(t *testing.T) {
 		t.Fatal(err)
 	}
 	testmainPath := filepath.Join(filepath.Dir(exePath), "_testmain.go")
-	source, err := ioutil.ReadFile(testmainPath)
+	source, err := os.ReadFile(testmainPath)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/go/testdata/script/test_race_install_cgo.txt b/src/cmd/go/testdata/script/test_race_install_cgo.txt
index 82f00f2086..3f4eb90e3f 100644
--- a/src/cmd/go/testdata/script/test_race_install_cgo.txt
+++ b/src/cmd/go/testdata/script/test_race_install_cgo.txt
@@ -29,7 +29,6 @@ go 1.16
 package main
 
 import (
-	"io/ioutil"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -37,7 +36,7 @@ import (
 )
 
 func main() {
-	b, err := ioutil.ReadFile(os.Args[1])
+	b, err := os.ReadFile(os.Args[1])
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
@@ -59,7 +58,6 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"time"
 )
@@ -67,7 +65,7 @@ import (
 
 func main() {
 	var t1 time.Time
-	b1, err := ioutil.ReadFile(os.Args[1])
+	b1, err := os.ReadFile(os.Args[1])
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
@@ -78,7 +76,7 @@ func main() {
 	}
 
 	var t2 time.Time
-	b2, err := ioutil.ReadFile(os.Args[2])
+	b2, err := os.ReadFile(os.Args[2])
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index 719c681a3e..2793c2c2a4 100644
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -15,7 +15,6 @@ import (
 	"go/token"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -137,7 +136,7 @@ func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error
 			if err != nil {
 				return err
 			}
-			err = ioutil.WriteFile(filename, res, perm)
+			err = os.WriteFile(filename, res, perm)
 			if err != nil {
 				os.Rename(bakname, filename)
 				return err
@@ -278,7 +277,7 @@ const chmodSupported = runtime.GOOS != "windows"
 // the chosen file name.
 func backupFile(filename string, data []byte, perm fs.FileMode) (string, error) {
 	// create backup file
-	f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
+	f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename))
 	if err != nil {
 		return "", err
 	}
diff --git a/src/cmd/gofmt/gofmt_test.go b/src/cmd/gofmt/gofmt_test.go
index 98d3eb7eb2..bf2adfe64c 100644
--- a/src/cmd/gofmt/gofmt_test.go
+++ b/src/cmd/gofmt/gofmt_test.go
@@ -7,7 +7,6 @@ package main
 import (
 	"bytes"
 	"flag"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -93,7 +92,7 @@ func runTest(t *testing.T, in, out string) {
 		return
 	}
 
-	expected, err := ioutil.ReadFile(out)
+	expected, err := os.ReadFile(out)
 	if err != nil {
 		t.Error(err)
 		return
@@ -102,7 +101,7 @@ func runTest(t *testing.T, in, out string) {
 	if got := buf.Bytes(); !bytes.Equal(got, expected) {
 		if *update {
 			if in != out {
-				if err := ioutil.WriteFile(out, got, 0666); err != nil {
+				if err := os.WriteFile(out, got, 0666); err != nil {
 					t.Error(err)
 				}
 				return
@@ -116,7 +115,7 @@ func runTest(t *testing.T, in, out string) {
 		if err == nil {
 			t.Errorf("%s", d)
 		}
-		if err := ioutil.WriteFile(in+".gofmt", got, 0666); err != nil {
+		if err := os.WriteFile(in+".gofmt", got, 0666); err != nil {
 			t.Error(err)
 		}
 	}
@@ -157,7 +156,7 @@ func TestCRLF(t *testing.T) {
 	const input = "testdata/crlf.input"   // must contain CR/LF's
 	const golden = "testdata/crlf.golden" // must not contain any CR's
 
-	data, err := ioutil.ReadFile(input)
+	data, err := os.ReadFile(input)
 	if err != nil {
 		t.Error(err)
 	}
@@ -165,7 +164,7 @@ func TestCRLF(t *testing.T) {
 		t.Errorf("%s contains no CR/LF's", input)
 	}
 
-	data, err = ioutil.ReadFile(golden)
+	data, err = os.ReadFile(golden)
 	if err != nil {
 		t.Error(err)
 	}
@@ -175,7 +174,7 @@ func TestCRLF(t *testing.T) {
 }
 
 func TestBackupFile(t *testing.T) {
-	dir, err := ioutil.TempDir("", "gofmt_test")
+	dir, err := os.MkdirTemp("", "gofmt_test")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/nm/nm_test.go b/src/cmd/nm/nm_test.go
index 382446e9fe..0d51b07a44 100644
--- a/src/cmd/nm/nm_test.go
+++ b/src/cmd/nm/nm_test.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"internal/obscuretestdata"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -31,7 +30,7 @@ func testMain(m *testing.M) int {
 		return 0
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestNM")
+	tmpDir, err := os.MkdirTemp("", "TestNM")
 	if err != nil {
 		fmt.Println("TempDir failed:", err)
 		return 2
@@ -88,7 +87,7 @@ func TestNonGoExecs(t *testing.T) {
 
 func testGoExec(t *testing.T, iscgo, isexternallinker bool) {
 	t.Parallel()
-	tmpdir, err := ioutil.TempDir("", "TestGoExec")
+	tmpdir, err := os.MkdirTemp("", "TestGoExec")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -222,7 +221,7 @@ func TestGoExec(t *testing.T) {
 
 func testGoLib(t *testing.T, iscgo bool) {
 	t.Parallel()
-	tmpdir, err := ioutil.TempDir("", "TestGoLib")
+	tmpdir, err := os.MkdirTemp("", "TestGoLib")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -245,7 +244,7 @@ func testGoLib(t *testing.T, iscgo bool) {
 		err = e
 	}
 	if err == nil {
-		err = ioutil.WriteFile(filepath.Join(libpath, "go.mod"), []byte("module mylib\n"), 0666)
+		err = os.WriteFile(filepath.Join(libpath, "go.mod"), []byte("module mylib\n"), 0666)
 	}
 	if err != nil {
 		t.Fatal(err)
diff --git a/src/cmd/objdump/objdump_test.go b/src/cmd/objdump/objdump_test.go
index cb692e7a81..edaca774f7 100644
--- a/src/cmd/objdump/objdump_test.go
+++ b/src/cmd/objdump/objdump_test.go
@@ -10,7 +10,6 @@ import (
 	"fmt"
 	"go/build"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -39,7 +38,7 @@ func TestMain(m *testing.M) {
 
 func buildObjdump() error {
 	var err error
-	tmp, err = ioutil.TempDir("", "TestObjDump")
+	tmp, err = os.MkdirTemp("", "TestObjDump")
 	if err != nil {
 		return fmt.Errorf("TempDir failed: %v", err)
 	}
@@ -320,7 +319,7 @@ func TestGoobjFileNumber(t *testing.T) {
 
 	t.Parallel()
 
-	tmpdir, err := ioutil.TempDir("", "TestGoobjFileNumber")
+	tmpdir, err := os.MkdirTemp("", "TestGoobjFileNumber")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/pack/pack_test.go b/src/cmd/pack/pack_test.go
index 9f65705def..218c7acda6 100644
--- a/src/cmd/pack/pack_test.go
+++ b/src/cmd/pack/pack_test.go
@@ -12,7 +12,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -22,7 +21,7 @@ import (
 
 // tmpDir creates a temporary directory and returns its name.
 func tmpDir(t *testing.T) string {
-	name, err := ioutil.TempDir("", "pack")
+	name, err := os.MkdirTemp("", "pack")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -158,7 +157,7 @@ func TestExtract(t *testing.T) {
 	ar = openArchive(name, os.O_RDONLY, []string{goodbyeFile.name})
 	ar.scan(ar.extractContents)
 	ar.a.File().Close()
-	data, err := ioutil.ReadFile(goodbyeFile.name)
+	data, err := os.ReadFile(goodbyeFile.name)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -183,7 +182,7 @@ func TestHello(t *testing.T) {
 			println("hello world")
 		}
 	`
-	err := ioutil.WriteFile(hello, []byte(prog), 0666)
+	err := os.WriteFile(hello, []byte(prog), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -251,7 +250,7 @@ func TestLargeDefs(t *testing.T) {
 			println("ok")
 		}
 	`
-	err = ioutil.WriteFile(main, []byte(prog), 0666)
+	err = os.WriteFile(main, []byte(prog), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -281,13 +280,13 @@ func TestIssue21703(t *testing.T) {
 	defer os.RemoveAll(dir)
 
 	const aSrc = `package a; const X = "\n!\n"`
-	err := ioutil.WriteFile(filepath.Join(dir, "a.go"), []byte(aSrc), 0666)
+	err := os.WriteFile(filepath.Join(dir, "a.go"), []byte(aSrc), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	const bSrc = `package b; import _ "a"`
-	err = ioutil.WriteFile(filepath.Join(dir, "b.go"), []byte(bSrc), 0666)
+	err = os.WriteFile(filepath.Join(dir, "b.go"), []byte(bSrc), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/cmd/trace/annotations_test.go b/src/cmd/trace/annotations_test.go
index a9068d53c1..9c2d027366 100644
--- a/src/cmd/trace/annotations_test.go
+++ b/src/cmd/trace/annotations_test.go
@@ -12,7 +12,7 @@ import (
 	"flag"
 	"fmt"
 	traceparser "internal/trace"
-	"io/ioutil"
+	"os"
 	"reflect"
 	"runtime/debug"
 	"runtime/trace"
@@ -386,7 +386,7 @@ func saveTrace(buf *bytes.Buffer, name string) {
 	if !*saveTraces {
 		return
 	}
-	if err := ioutil.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
+	if err := os.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
 		panic(fmt.Errorf("failed to write trace file: %v", err))
 	}
 }
diff --git a/src/cmd/trace/pprof.go b/src/cmd/trace/pprof.go
index a31d71b013..a73ff5336a 100644
--- a/src/cmd/trace/pprof.go
+++ b/src/cmd/trace/pprof.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"internal/trace"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"os/exec"
@@ -294,7 +293,7 @@ func serveSVGProfile(prof func(w io.Writer, r *http.Request) error) http.Handler
 			return
 		}
 
-		blockf, err := ioutil.TempFile("", "block")
+		blockf, err := os.CreateTemp("", "block")
 		if err != nil {
 			http.Error(w, fmt.Sprintf("failed to create temp file: %v", err), http.StatusInternalServerError)
 			return
diff --git a/src/cmd/vet/vet_test.go b/src/cmd/vet/vet_test.go
index 5d8139d977..d15d1ce377 100644
--- a/src/cmd/vet/vet_test.go
+++ b/src/cmd/vet/vet_test.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
@@ -32,7 +31,7 @@ func TestMain(m *testing.M) {
 }
 
 func testMain(m *testing.M) int {
-	dir, err := ioutil.TempDir("", "vet_test")
+	dir, err := os.MkdirTemp("", "vet_test")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		return 1
@@ -345,7 +344,7 @@ var (
 func wantedErrors(file, short string) (errs []wantedError) {
 	cache := make(map[string]*regexp.Regexp)
 
-	src, err := ioutil.ReadFile(file)
+	src, err := os.ReadFile(file)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/compress/bzip2/bzip2_test.go b/src/compress/bzip2/bzip2_test.go
index 98477791b3..e6065cb43f 100644
--- a/src/compress/bzip2/bzip2_test.go
+++ b/src/compress/bzip2/bzip2_test.go
@@ -9,7 +9,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -22,7 +22,7 @@ func mustDecodeHex(s string) []byte {
 }
 
 func mustLoadFile(f string) []byte {
-	b, err := ioutil.ReadFile(f)
+	b, err := os.ReadFile(f)
 	if err != nil {
 		panic(err)
 	}
diff --git a/src/compress/flate/deflate_test.go b/src/compress/flate/deflate_test.go
index 6fc5abf4d5..ff56712123 100644
--- a/src/compress/flate/deflate_test.go
+++ b/src/compress/flate/deflate_test.go
@@ -10,8 +10,8 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"math/rand"
+	"os"
 	"reflect"
 	"runtime/debug"
 	"sync"
@@ -387,7 +387,7 @@ func TestDeflateInflateString(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 	for _, test := range deflateInflateStringTests {
-		gold, err := ioutil.ReadFile(test.filename)
+		gold, err := os.ReadFile(test.filename)
 		if err != nil {
 			t.Error(err)
 		}
@@ -685,7 +685,7 @@ func (w *failWriter) Write(b []byte) (int, error) {
 
 func TestWriterPersistentError(t *testing.T) {
 	t.Parallel()
-	d, err := ioutil.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
+	d, err := os.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
 	if err != nil {
 		t.Fatalf("ReadFile: %v", err)
 	}
diff --git a/src/compress/flate/huffman_bit_writer_test.go b/src/compress/flate/huffman_bit_writer_test.go
index 882d3abec1..a57799cae0 100644
--- a/src/compress/flate/huffman_bit_writer_test.go
+++ b/src/compress/flate/huffman_bit_writer_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -38,7 +37,7 @@ func TestBlockHuff(t *testing.T) {
 }
 
 func testBlockHuff(t *testing.T, in, out string) {
-	all, err := ioutil.ReadFile(in)
+	all, err := os.ReadFile(in)
 	if err != nil {
 		t.Error(err)
 		return
@@ -49,7 +48,7 @@ func testBlockHuff(t *testing.T, in, out string) {
 	bw.flush()
 	got := buf.Bytes()
 
-	want, err := ioutil.ReadFile(out)
+	want, err := os.ReadFile(out)
 	if err != nil && !*update {
 		t.Error(err)
 		return
@@ -60,7 +59,7 @@ func testBlockHuff(t *testing.T, in, out string) {
 		if *update {
 			if in != out {
 				t.Logf("Updating %q", out)
-				if err := ioutil.WriteFile(out, got, 0666); err != nil {
+				if err := os.WriteFile(out, got, 0666); err != nil {
 					t.Error(err)
 				}
 				return
@@ -70,7 +69,7 @@ func testBlockHuff(t *testing.T, in, out string) {
 		}
 
 		t.Errorf("%q != %q (see %q)", in, out, in+".got")
-		if err := ioutil.WriteFile(in+".got", got, 0666); err != nil {
+		if err := os.WriteFile(in+".got", got, 0666); err != nil {
 			t.Error(err)
 		}
 		return
@@ -85,7 +84,7 @@ func testBlockHuff(t *testing.T, in, out string) {
 	got = buf.Bytes()
 	if !bytes.Equal(got, want) {
 		t.Errorf("after reset %q != %q (see %q)", in, out, in+".reset.got")
-		if err := ioutil.WriteFile(in+".reset.got", got, 0666); err != nil {
+		if err := os.WriteFile(in+".reset.got", got, 0666); err != nil {
 			t.Error(err)
 		}
 		return
@@ -186,7 +185,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 	if *update {
 		if test.input != "" {
 			t.Logf("Updating %q", test.want)
-			input, err := ioutil.ReadFile(test.input)
+			input, err := os.ReadFile(test.input)
 			if err != nil {
 				t.Error(err)
 				return
@@ -216,12 +215,12 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 
 	if test.input != "" {
 		t.Logf("Testing %q", test.want)
-		input, err := ioutil.ReadFile(test.input)
+		input, err := os.ReadFile(test.input)
 		if err != nil {
 			t.Error(err)
 			return
 		}
-		want, err := ioutil.ReadFile(test.want)
+		want, err := os.ReadFile(test.want)
 		if err != nil {
 			t.Error(err)
 			return
@@ -233,7 +232,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 		got := buf.Bytes()
 		if !bytes.Equal(got, want) {
 			t.Errorf("writeBlock did not yield expected result for file %q with input. See %q", test.want, test.want+".got")
-			if err := ioutil.WriteFile(test.want+".got", got, 0666); err != nil {
+			if err := os.WriteFile(test.want+".got", got, 0666); err != nil {
 				t.Error(err)
 			}
 		}
@@ -247,7 +246,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 		got = buf.Bytes()
 		if !bytes.Equal(got, want) {
 			t.Errorf("reset: writeBlock did not yield expected result for file %q with input. See %q", test.want, test.want+".reset.got")
-			if err := ioutil.WriteFile(test.want+".reset.got", got, 0666); err != nil {
+			if err := os.WriteFile(test.want+".reset.got", got, 0666); err != nil {
 				t.Error(err)
 			}
 			return
@@ -256,7 +255,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 		testWriterEOF(t, "wb", test, true)
 	}
 	t.Logf("Testing %q", test.wantNoInput)
-	wantNI, err := ioutil.ReadFile(test.wantNoInput)
+	wantNI, err := os.ReadFile(test.wantNoInput)
 	if err != nil {
 		t.Error(err)
 		return
@@ -268,7 +267,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 	got := buf.Bytes()
 	if !bytes.Equal(got, wantNI) {
 		t.Errorf("writeBlock did not yield expected result for file %q with input. See %q", test.wantNoInput, test.wantNoInput+".got")
-		if err := ioutil.WriteFile(test.want+".got", got, 0666); err != nil {
+		if err := os.WriteFile(test.want+".got", got, 0666); err != nil {
 			t.Error(err)
 		}
 	} else if got[0]&1 == 1 {
@@ -286,7 +285,7 @@ func testBlock(t *testing.T, test huffTest, ttype string) {
 	got = buf.Bytes()
 	if !bytes.Equal(got, wantNI) {
 		t.Errorf("reset: writeBlock did not yield expected result for file %q without input. See %q", test.want, test.want+".reset.got")
-		if err := ioutil.WriteFile(test.want+".reset.got", got, 0666); err != nil {
+		if err := os.WriteFile(test.want+".reset.got", got, 0666); err != nil {
 			t.Error(err)
 		}
 		return
@@ -325,7 +324,7 @@ func testWriterEOF(t *testing.T, ttype string, test huffTest, useInput bool) {
 	var input []byte
 	if useInput {
 		var err error
-		input, err = ioutil.ReadFile(test.input)
+		input, err = os.ReadFile(test.input)
 		if err != nil {
 			t.Error(err)
 			return
diff --git a/src/compress/flate/reader_test.go b/src/compress/flate/reader_test.go
index eb32c89184..94610fbb78 100644
--- a/src/compress/flate/reader_test.go
+++ b/src/compress/flate/reader_test.go
@@ -7,7 +7,7 @@ package flate
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
+	"os"
 	"runtime"
 	"strings"
 	"testing"
@@ -80,7 +80,7 @@ var sizes = []struct {
 
 func doBench(b *testing.B, f func(b *testing.B, buf []byte, level, n int)) {
 	for _, suite := range suites {
-		buf, err := ioutil.ReadFile(suite.file)
+		buf, err := os.ReadFile(suite.file)
 		if err != nil {
 			b.Fatal(err)
 		}
diff --git a/src/compress/lzw/reader_test.go b/src/compress/lzw/reader_test.go
index 6d91dd806f..d1eb76d042 100644
--- a/src/compress/lzw/reader_test.go
+++ b/src/compress/lzw/reader_test.go
@@ -8,8 +8,8 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
+	"os"
 	"runtime"
 	"strconv"
 	"strings"
@@ -218,7 +218,7 @@ func TestNoLongerSavingPriorExpansions(t *testing.T) {
 }
 
 func BenchmarkDecoder(b *testing.B) {
-	buf, err := ioutil.ReadFile("../testdata/e.txt")
+	buf, err := os.ReadFile("../testdata/e.txt")
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/compress/lzw/writer_test.go b/src/compress/lzw/writer_test.go
index 33a28bdd3a..1a5dbcae93 100644
--- a/src/compress/lzw/writer_test.go
+++ b/src/compress/lzw/writer_test.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"runtime"
@@ -125,7 +124,7 @@ func TestSmallLitWidth(t *testing.T) {
 }
 
 func BenchmarkEncoder(b *testing.B) {
-	buf, err := ioutil.ReadFile("../testdata/e.txt")
+	buf, err := os.ReadFile("../testdata/e.txt")
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/compress/zlib/writer_test.go b/src/compress/zlib/writer_test.go
index c518729146..f0b38880a6 100644
--- a/src/compress/zlib/writer_test.go
+++ b/src/compress/zlib/writer_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"testing"
 )
@@ -95,7 +94,7 @@ func testFileLevelDictReset(t *testing.T, fn string, level int, dict []byte) {
 	var b0 []byte
 	var err error
 	if fn != "" {
-		b0, err = ioutil.ReadFile(fn)
+		b0, err = os.ReadFile(fn)
 		if err != nil {
 			t.Errorf("%s (level=%d): %v", fn, level, err)
 			return
diff --git a/src/crypto/md5/gen.go b/src/crypto/md5/gen.go
index a11f22059f..1468924cbc 100644
--- a/src/crypto/md5/gen.go
+++ b/src/crypto/md5/gen.go
@@ -15,8 +15,8 @@ import (
 	"bytes"
 	"flag"
 	"go/format"
-	"io/ioutil"
 	"log"
+	"os"
 	"strings"
 	"text/template"
 )
@@ -37,7 +37,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = ioutil.WriteFile(*filename, data, 0644)
+	err = os.WriteFile(*filename, data, 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/crypto/tls/handshake_test.go b/src/crypto/tls/handshake_test.go
index 605be587b5..d9ff9fe948 100644
--- a/src/crypto/tls/handshake_test.go
+++ b/src/crypto/tls/handshake_test.go
@@ -13,7 +13,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/exec"
@@ -224,7 +223,7 @@ func parseTestData(r io.Reader) (flows [][]byte, err error) {
 
 // tempFile creates a temp file containing contents and returns its path.
 func tempFile(contents string) string {
-	file, err := ioutil.TempFile("", "go-tls-test")
+	file, err := os.CreateTemp("", "go-tls-test")
 	if err != nil {
 		panic("failed to create temp file: " + err.Error())
 	}
diff --git a/src/crypto/tls/link_test.go b/src/crypto/tls/link_test.go
index 8224216b5c..8c392ff7c4 100644
--- a/src/crypto/tls/link_test.go
+++ b/src/crypto/tls/link_test.go
@@ -7,7 +7,6 @@ package tls
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -77,7 +76,7 @@ func main() { tls.Dial("", "", nil) }
 	exeFile := filepath.Join(tmpDir, "x.exe")
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if err := ioutil.WriteFile(goFile, []byte(tt.program), 0644); err != nil {
+			if err := os.WriteFile(goFile, []byte(tt.program), 0644); err != nil {
 				t.Fatal(err)
 			}
 			os.Remove(exeFile)
diff --git a/src/crypto/tls/tls.go b/src/crypto/tls/tls.go
index bf577cadea..19884f96e7 100644
--- a/src/crypto/tls/tls.go
+++ b/src/crypto/tls/tls.go
@@ -22,8 +22,8 @@ import (
 	"encoding/pem"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
+	"os"
 	"strings"
 )
 
@@ -222,11 +222,11 @@ func (d *Dialer) DialContext(ctx context.Context, network, addr string) (net.Con
 // form a certificate chain. On successful return, Certificate.Leaf will
 // be nil because the parsed form of the certificate is not retained.
 func LoadX509KeyPair(certFile, keyFile string) (Certificate, error) {
-	certPEMBlock, err := ioutil.ReadFile(certFile)
+	certPEMBlock, err := os.ReadFile(certFile)
 	if err != nil {
 		return Certificate{}, err
 	}
-	keyPEMBlock, err := ioutil.ReadFile(keyFile)
+	keyPEMBlock, err := os.ReadFile(keyFile)
 	if err != nil {
 		return Certificate{}, err
 	}
diff --git a/src/crypto/x509/name_constraints_test.go b/src/crypto/x509/name_constraints_test.go
index 34055d07b5..3826c82c38 100644
--- a/src/crypto/x509/name_constraints_test.go
+++ b/src/crypto/x509/name_constraints_test.go
@@ -14,7 +14,6 @@ import (
 	"encoding/hex"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"math/big"
 	"net"
 	"net/url"
@@ -2005,7 +2004,7 @@ func TestConstraintCases(t *testing.T) {
 }
 
 func writePEMsToTempFile(certs []*Certificate) *os.File {
-	file, err := ioutil.TempFile("", "name_constraints_test")
+	file, err := os.CreateTemp("", "name_constraints_test")
 	if err != nil {
 		panic("cannot create tempfile")
 	}
diff --git a/src/crypto/x509/root_ios_gen.go b/src/crypto/x509/root_ios_gen.go
index 2bcdab1a77..8bc6e7d9c4 100644
--- a/src/crypto/x509/root_ios_gen.go
+++ b/src/crypto/x509/root_ios_gen.go
@@ -27,9 +27,9 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 	"path"
 	"sort"
 	"strings"
@@ -155,7 +155,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := ioutil.WriteFile(*output, source, 0644); err != nil {
+	if err := os.WriteFile(*output, source, 0644); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/src/crypto/x509/root_plan9.go b/src/crypto/x509/root_plan9.go
index 09f0e23033..2dc4aaf5d7 100644
--- a/src/crypto/x509/root_plan9.go
+++ b/src/crypto/x509/root_plan9.go
@@ -7,7 +7,6 @@
 package x509
 
 import (
-	"io/ioutil"
 	"os"
 )
 
@@ -24,7 +23,7 @@ func loadSystemRoots() (*CertPool, error) {
 	roots := NewCertPool()
 	var bestErr error
 	for _, file := range certFiles {
-		data, err := ioutil.ReadFile(file)
+		data, err := os.ReadFile(file)
 		if err == nil {
 			roots.AppendCertsFromPEM(data)
 			return roots, nil
diff --git a/src/crypto/x509/root_unix.go b/src/crypto/x509/root_unix.go
index 1090b69f83..3c643466ed 100644
--- a/src/crypto/x509/root_unix.go
+++ b/src/crypto/x509/root_unix.go
@@ -40,7 +40,7 @@ func loadSystemRoots() (*CertPool, error) {
 
 	var firstErr error
 	for _, file := range files {
-		data, err := ioutil.ReadFile(file)
+		data, err := os.ReadFile(file)
 		if err == nil {
 			roots.AppendCertsFromPEM(data)
 			break
@@ -68,7 +68,7 @@ func loadSystemRoots() (*CertPool, error) {
 			continue
 		}
 		for _, fi := range fis {
-			data, err := ioutil.ReadFile(directory + "/" + fi.Name())
+			data, err := os.ReadFile(directory + "/" + fi.Name())
 			if err == nil {
 				roots.AppendCertsFromPEM(data)
 			}
diff --git a/src/crypto/x509/root_unix_test.go b/src/crypto/x509/root_unix_test.go
index b2e832ff36..878ed7c2fa 100644
--- a/src/crypto/x509/root_unix_test.go
+++ b/src/crypto/x509/root_unix_test.go
@@ -9,7 +9,6 @@ package x509
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -147,7 +146,7 @@ func TestLoadSystemCertsLoadColonSeparatedDirs(t *testing.T) {
 		os.Setenv(certFileEnv, origFile)
 	}()
 
-	tmpDir, err := ioutil.TempDir(os.TempDir(), "x509-issue35325")
+	tmpDir, err := os.MkdirTemp(os.TempDir(), "x509-issue35325")
 	if err != nil {
 		t.Fatalf("Failed to create temporary directory: %v", err)
 	}
@@ -166,7 +165,7 @@ func TestLoadSystemCertsLoadColonSeparatedDirs(t *testing.T) {
 			t.Fatalf("Failed to create certificate dir: %v", err)
 		}
 		certOutFile := filepath.Join(certDir, "cert.crt")
-		if err := ioutil.WriteFile(certOutFile, []byte(certPEM), 0655); err != nil {
+		if err := os.WriteFile(certOutFile, []byte(certPEM), 0655); err != nil {
 			t.Fatalf("Failed to write certificate to file: %v", err)
 		}
 		certDirs = append(certDirs, certDir)
diff --git a/src/debug/dwarf/dwarf5ranges_test.go b/src/debug/dwarf/dwarf5ranges_test.go
index 2229d439a5..0ff1a55bc9 100644
--- a/src/debug/dwarf/dwarf5ranges_test.go
+++ b/src/debug/dwarf/dwarf5ranges_test.go
@@ -6,13 +6,13 @@ package dwarf
 
 import (
 	"encoding/binary"
-	"io/ioutil"
+	"os"
 	"reflect"
 	"testing"
 )
 
 func TestDwarf5Ranges(t *testing.T) {
-	rngLists, err := ioutil.ReadFile("testdata/debug_rnglists")
+	rngLists, err := os.ReadFile("testdata/debug_rnglists")
 	if err != nil {
 		t.Fatalf("could not read test data: %v", err)
 	}
diff --git a/src/debug/gosym/pclntab_test.go b/src/debug/gosym/pclntab_test.go
index f93a5bf5e5..7347139b5d 100644
--- a/src/debug/gosym/pclntab_test.go
+++ b/src/debug/gosym/pclntab_test.go
@@ -10,7 +10,6 @@ import (
 	"debug/elf"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -31,7 +30,7 @@ func dotest(t *testing.T) {
 		t.Skipf("skipping on non-AMD64 system %s", runtime.GOARCH)
 	}
 	var err error
-	pclineTempDir, err = ioutil.TempDir("", "pclinetest")
+	pclineTempDir, err = os.MkdirTemp("", "pclinetest")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -278,7 +277,7 @@ func TestPCLine(t *testing.T) {
 // }
 // [END]
 func Test115PclnParsing(t *testing.T) {
-	zippedDat, err := ioutil.ReadFile("testdata/pcln115.gz")
+	zippedDat, err := os.ReadFile("testdata/pcln115.gz")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/debug/pe/file_test.go b/src/debug/pe/file_test.go
index d96cd30904..58deff1450 100644
--- a/src/debug/pe/file_test.go
+++ b/src/debug/pe/file_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"debug/dwarf"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -354,7 +353,7 @@ func testDWARF(t *testing.T, linktype int) {
 	}
 	testenv.MustHaveGoRun(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestDWARF")
+	tmpdir, err := os.MkdirTemp("", "TestDWARF")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -473,7 +472,7 @@ func TestBSSHasZeros(t *testing.T) {
 		t.Skip("skipping test: gcc is missing")
 	}
 
-	tmpdir, err := ioutil.TempDir("", "TestBSSHasZeros")
+	tmpdir, err := os.MkdirTemp("", "TestBSSHasZeros")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -492,7 +491,7 @@ main(void)
 	return 0;
 }
 `
-	err = ioutil.WriteFile(srcpath, []byte(src), 0644)
+	err = os.WriteFile(srcpath, []byte(src), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -597,14 +596,14 @@ func TestBuildingWindowsGUI(t *testing.T) {
 	if runtime.GOOS != "windows" {
 		t.Skip("skipping windows only test")
 	}
-	tmpdir, err := ioutil.TempDir("", "TestBuildingWindowsGUI")
+	tmpdir, err := os.MkdirTemp("", "TestBuildingWindowsGUI")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	src := filepath.Join(tmpdir, "a.go")
-	err = ioutil.WriteFile(src, []byte(`package main; func main() {}`), 0644)
+	err = os.WriteFile(src, []byte(`package main; func main() {}`), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -684,7 +683,7 @@ func TestInvalidOptionalHeaderMagic(t *testing.T) {
 func TestImportedSymbolsNoPanicMissingOptionalHeader(t *testing.T) {
 	// https://golang.org/issue/30250
 	// ImportedSymbols shouldn't panic if optional headers is missing
-	data, err := ioutil.ReadFile("testdata/gcc-amd64-mingw-obj")
+	data, err := os.ReadFile("testdata/gcc-amd64-mingw-obj")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/embed/internal/embedtest/embedx_test.go b/src/embed/internal/embedtest/embedx_test.go
index 53d45488f1..20d5a28c11 100644
--- a/src/embed/internal/embedtest/embedx_test.go
+++ b/src/embed/internal/embedtest/embedx_test.go
@@ -6,7 +6,7 @@ package embedtest_test
 
 import (
 	"embed"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -59,7 +59,7 @@ func TestXGlobal(t *testing.T) {
 	testString(t, concurrency2, "concurrency2", "Concurrency is not parallelism.\n")
 	testString(t, string(glass2), "glass2", "I can eat glass and it doesn't hurt me.\n")
 
-	big, err := ioutil.ReadFile("testdata/ascii.txt")
+	big, err := os.ReadFile("testdata/ascii.txt")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/go/build/build_test.go b/src/go/build/build_test.go
index 5a4a2d62f5..5a3e9ee714 100644
--- a/src/go/build/build_test.go
+++ b/src/go/build/build_test.go
@@ -8,7 +8,6 @@ import (
 	"flag"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -454,7 +453,7 @@ func TestImportDirNotExist(t *testing.T) {
 	testenv.MustHaveGoBuild(t) // really must just have source
 	ctxt := Default
 
-	emptyDir, err := ioutil.TempDir("", t.Name())
+	emptyDir, err := os.MkdirTemp("", t.Name())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -592,7 +591,7 @@ func TestImportPackageOutsideModule(t *testing.T) {
 
 	// Create a GOPATH in a temporary directory. We don't use testdata
 	// because it's in GOROOT, which interferes with the module heuristic.
-	gopath, err := ioutil.TempDir("", "gobuild-notmodule")
+	gopath, err := os.MkdirTemp("", "gobuild-notmodule")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -600,7 +599,7 @@ func TestImportPackageOutsideModule(t *testing.T) {
 	if err := os.MkdirAll(filepath.Join(gopath, "src/example.com/p"), 0777); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(gopath, "src/example.com/p/p.go"), []byte("package p"), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(gopath, "src/example.com/p/p.go"), []byte("package p"), 0666); err != nil {
 		t.Fatal(err)
 	}
 
@@ -656,12 +655,12 @@ func TestIssue23594(t *testing.T) {
 // Verifies golang.org/issue/34752.
 func TestMissingImportErrorRepetition(t *testing.T) {
 	testenv.MustHaveGoBuild(t) // need 'go list' internally
-	tmp, err := ioutil.TempDir("", "")
+	tmp, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmp)
-	if err := ioutil.WriteFile(filepath.Join(tmp, "go.mod"), []byte("module m"), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(tmp, "go.mod"), []byte("module m"), 0666); err != nil {
 		t.Fatal(err)
 	}
 	defer os.Setenv("GO111MODULE", os.Getenv("GO111MODULE"))
diff --git a/src/go/doc/doc_test.go b/src/go/doc/doc_test.go
index ab98bed62b..cbdca62aa1 100644
--- a/src/go/doc/doc_test.go
+++ b/src/go/doc/doc_test.go
@@ -13,7 +13,7 @@ import (
 	"go/printer"
 	"go/token"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -127,7 +127,7 @@ func test(t *testing.T, mode Mode) {
 		// update golden file if necessary
 		golden := filepath.Join(dataDir, fmt.Sprintf("%s.%d.golden", pkg.Name, mode))
 		if *update {
-			err := ioutil.WriteFile(golden, got, 0644)
+			err := os.WriteFile(golden, got, 0644)
 			if err != nil {
 				t.Error(err)
 			}
@@ -135,7 +135,7 @@ func test(t *testing.T, mode Mode) {
 		}
 
 		// get golden file
-		want, err := ioutil.ReadFile(golden)
+		want, err := os.ReadFile(golden)
 		if err != nil {
 			t.Error(err)
 			continue
diff --git a/src/go/format/benchmark_test.go b/src/go/format/benchmark_test.go
index 7bd45c0e95..ac19aa3bf5 100644
--- a/src/go/format/benchmark_test.go
+++ b/src/go/format/benchmark_test.go
@@ -12,7 +12,7 @@ import (
 	"flag"
 	"fmt"
 	"go/format"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -67,7 +67,7 @@ func BenchmarkFormat(b *testing.B) {
 
 		if *debug {
 			filename := t.name + ".src"
-			err := ioutil.WriteFile(filename, data, 0660)
+			err := os.WriteFile(filename, data, 0660)
 			if err != nil {
 				b.Fatalf("couldn't write %s: %v", filename, err)
 			}
diff --git a/src/go/format/format_test.go b/src/go/format/format_test.go
index 58e088ede3..27f4c74cdf 100644
--- a/src/go/format/format_test.go
+++ b/src/go/format/format_test.go
@@ -9,7 +9,7 @@ import (
 	"go/ast"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
+	"os"
 	"strings"
 	"testing"
 )
@@ -38,7 +38,7 @@ func diff(t *testing.T, dst, src []byte) {
 }
 
 func TestNode(t *testing.T) {
-	src, err := ioutil.ReadFile(testfile)
+	src, err := os.ReadFile(testfile)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -96,7 +96,7 @@ func TestNodeNoModify(t *testing.T) {
 }
 
 func TestSource(t *testing.T) {
-	src, err := ioutil.ReadFile(testfile)
+	src, err := os.ReadFile(testfile)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/go/importer/importer_test.go b/src/go/importer/importer_test.go
index ff6e12c0da..0f5121d802 100644
--- a/src/go/importer/importer_test.go
+++ b/src/go/importer/importer_test.go
@@ -8,7 +8,6 @@ import (
 	"go/token"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"runtime"
@@ -52,7 +51,7 @@ func TestForCompiler(t *testing.T) {
 		mathBigInt := pkg.Scope().Lookup("Int")
 		posn := fset.Position(mathBigInt.Pos()) // "$GOROOT/src/math/big/int.go:25:1"
 		filename := strings.Replace(posn.Filename, "$GOROOT", runtime.GOROOT(), 1)
-		data, err := ioutil.ReadFile(filename)
+		data, err := os.ReadFile(filename)
 		if err != nil {
 			t.Fatalf("can't read file containing declaration of math/big.Int: %v", err)
 		}
diff --git a/src/go/internal/gccgoimporter/importer_test.go b/src/go/internal/gccgoimporter/importer_test.go
index e4236a5867..35240c8fe6 100644
--- a/src/go/internal/gccgoimporter/importer_test.go
+++ b/src/go/internal/gccgoimporter/importer_test.go
@@ -7,7 +7,6 @@ package gccgoimporter
 import (
 	"go/types"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -150,7 +149,7 @@ func TestObjImporter(t *testing.T) {
 	}
 	t.Logf("gccgo version %d.%d", major, minor)
 
-	tmpdir, err := ioutil.TempDir("", "TestObjImporter")
+	tmpdir, err := os.MkdirTemp("", "TestObjImporter")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -159,7 +158,7 @@ func TestObjImporter(t *testing.T) {
 	initmap := make(map[*types.Package]InitData)
 	imp := GetImporter([]string{tmpdir}, initmap)
 
-	artmpdir, err := ioutil.TempDir("", "TestObjImporter")
+	artmpdir, err := os.MkdirTemp("", "TestObjImporter")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/go/internal/gcimporter/gcimporter_test.go b/src/go/internal/gcimporter/gcimporter_test.go
index 663753a18a..8991e3bdee 100644
--- a/src/go/internal/gcimporter/gcimporter_test.go
+++ b/src/go/internal/gcimporter/gcimporter_test.go
@@ -94,7 +94,7 @@ func testDir(t *testing.T, dir string, endTime time.Time) (nimports int) {
 }
 
 func mktmpdir(t *testing.T) string {
-	tmpdir, err := ioutil.TempDir("", "gcimporter_test")
+	tmpdir, err := os.MkdirTemp("", "gcimporter_test")
 	if err != nil {
 		t.Fatal("mktmpdir:", err)
 	}
@@ -199,7 +199,7 @@ func TestVersionHandling(t *testing.T) {
 
 		// create file with corrupted export data
 		// 1) read file
-		data, err := ioutil.ReadFile(filepath.Join(dir, name))
+		data, err := os.ReadFile(filepath.Join(dir, name))
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -216,7 +216,7 @@ func TestVersionHandling(t *testing.T) {
 		// 4) write the file
 		pkgpath += "_corrupted"
 		filename := filepath.Join(corruptdir, pkgpath) + ".a"
-		ioutil.WriteFile(filename, data, 0666)
+		os.WriteFile(filename, data, 0666)
 
 		// test that importing the corrupted file results in an error
 		_, err = Import(fset, make(map[string]*types.Package), pkgpath, corruptdir, nil)
diff --git a/src/go/internal/srcimporter/srcimporter.go b/src/go/internal/srcimporter/srcimporter.go
index 90bb3a9bc1..c4d501dcd9 100644
--- a/src/go/internal/srcimporter/srcimporter.go
+++ b/src/go/internal/srcimporter/srcimporter.go
@@ -14,7 +14,6 @@ import (
 	"go/token"
 	"go/types"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -200,7 +199,7 @@ func (p *Importer) parseFiles(dir string, filenames []string) ([]*ast.File, erro
 }
 
 func (p *Importer) cgo(bp *build.Package) (*ast.File, error) {
-	tmpdir, err := ioutil.TempDir("", "srcimporter")
+	tmpdir, err := os.MkdirTemp("", "srcimporter")
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/go/parser/interface.go b/src/go/parser/interface.go
index d5c18a9e2d..41d9a52847 100644
--- a/src/go/parser/interface.go
+++ b/src/go/parser/interface.go
@@ -14,6 +14,7 @@ import (
 	"io"
 	"io/fs"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strings"
 )
@@ -39,7 +40,7 @@ func readSource(filename string, src interface{}) ([]byte, error) {
 		}
 		return nil, errors.New("invalid source")
 	}
-	return ioutil.ReadFile(filename)
+	return os.ReadFile(filename)
 }
 
 // A Mode value is a set of flags (or 0).
diff --git a/src/go/parser/performance_test.go b/src/go/parser/performance_test.go
index f2732c0e2b..f81bcee969 100644
--- a/src/go/parser/performance_test.go
+++ b/src/go/parser/performance_test.go
@@ -6,14 +6,14 @@ package parser
 
 import (
 	"go/token"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
 var src = readFile("parser.go")
 
 func readFile(filename string) []byte {
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		panic(err)
 	}
diff --git a/src/go/printer/performance_test.go b/src/go/printer/performance_test.go
index e23de3fbae..e655fa13ee 100644
--- a/src/go/printer/performance_test.go
+++ b/src/go/printer/performance_test.go
@@ -12,8 +12,8 @@ import (
 	"go/ast"
 	"go/parser"
 	"io"
-	"io/ioutil"
 	"log"
+	"os"
 	"testing"
 )
 
@@ -29,7 +29,7 @@ func testprint(out io.Writer, file *ast.File) {
 func initialize() {
 	const filename = "testdata/parser.go"
 
-	src, err := ioutil.ReadFile(filename)
+	src, err := os.ReadFile(filename)
 	if err != nil {
 		log.Fatalf("%s", err)
 	}
diff --git a/src/go/printer/printer_test.go b/src/go/printer/printer_test.go
index b64bc6bfb7..45e501115a 100644
--- a/src/go/printer/printer_test.go
+++ b/src/go/printer/printer_test.go
@@ -13,7 +13,7 @@ import (
 	"go/parser"
 	"go/token"
 	"io"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 	"time"
@@ -119,7 +119,7 @@ func diff(aname, bname string, a, b []byte) error {
 }
 
 func runcheck(t *testing.T, source, golden string, mode checkMode) {
-	src, err := ioutil.ReadFile(source)
+	src, err := os.ReadFile(source)
 	if err != nil {
 		t.Error(err)
 		return
@@ -133,14 +133,14 @@ func runcheck(t *testing.T, source, golden string, mode checkMode) {
 
 	// update golden files if necessary
 	if *update {
-		if err := ioutil.WriteFile(golden, res, 0644); err != nil {
+		if err := os.WriteFile(golden, res, 0644); err != nil {
 			t.Error(err)
 		}
 		return
 	}
 
 	// get golden
-	gld, err := ioutil.ReadFile(golden)
+	gld, err := os.ReadFile(golden)
 	if err != nil {
 		t.Error(err)
 		return
@@ -552,7 +552,7 @@ func TestBaseIndent(t *testing.T) {
 	// are not indented (because their values must not change) and make
 	// this test fail.
 	const filename = "printer.go"
-	src, err := ioutil.ReadFile(filename)
+	src, err := os.ReadFile(filename)
 	if err != nil {
 		panic(err) // error in test
 	}
@@ -639,7 +639,7 @@ func (l *limitWriter) Write(buf []byte) (n int, err error) {
 func TestWriteErrors(t *testing.T) {
 	t.Parallel()
 	const filename = "printer.go"
-	src, err := ioutil.ReadFile(filename)
+	src, err := os.ReadFile(filename)
 	if err != nil {
 		panic(err) // error in test
 	}
diff --git a/src/go/scanner/scanner_test.go b/src/go/scanner/scanner_test.go
index 9d3bbbbb24..ab4c2dd962 100644
--- a/src/go/scanner/scanner_test.go
+++ b/src/go/scanner/scanner_test.go
@@ -6,7 +6,6 @@ package scanner
 
 import (
 	"go/token"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -893,7 +892,7 @@ func BenchmarkScan(b *testing.B) {
 func BenchmarkScanFile(b *testing.B) {
 	b.StopTimer()
 	const filename = "scanner.go"
-	src, err := ioutil.ReadFile(filename)
+	src, err := os.ReadFile(filename)
 	if err != nil {
 		panic(err)
 	}
diff --git a/src/go/types/check_test.go b/src/go/types/check_test.go
index 37b287a20d..841ca24511 100644
--- a/src/go/types/check_test.go
+++ b/src/go/types/check_test.go
@@ -34,6 +34,7 @@ import (
 	"go/token"
 	"internal/testenv"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"regexp"
 	"strings"
@@ -153,7 +154,7 @@ func errMap(t *testing.T, testname string, files []*ast.File) map[string][]strin
 
 	for _, file := range files {
 		filename := fset.Position(file.Package).Filename
-		src, err := ioutil.ReadFile(filename)
+		src, err := os.ReadFile(filename)
 		if err != nil {
 			t.Fatalf("%s: could not read %s", testname, filename)
 		}
diff --git a/src/go/types/hilbert_test.go b/src/go/types/hilbert_test.go
index 9783ce6dc9..77954d2f8b 100644
--- a/src/go/types/hilbert_test.go
+++ b/src/go/types/hilbert_test.go
@@ -12,7 +12,7 @@ import (
 	"go/importer"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	. "go/types"
@@ -27,7 +27,7 @@ func TestHilbert(t *testing.T) {
 	// generate source
 	src := program(*H, *out)
 	if *out != "" {
-		ioutil.WriteFile(*out, src, 0666)
+		os.WriteFile(*out, src, 0666)
 		return
 	}
 
diff --git a/src/hash/crc32/gen_const_ppc64le.go b/src/hash/crc32/gen_const_ppc64le.go
index bfb3b3a227..d7af018af4 100644
--- a/src/hash/crc32/gen_const_ppc64le.go
+++ b/src/hash/crc32/gen_const_ppc64le.go
@@ -27,7 +27,7 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 )
 
 var blocking = 32 * 1024
@@ -103,7 +103,7 @@ func main() {
 	genCrc32ConstTable(w, 0xeb31d82e, "Koop")
 	b := w.Bytes()
 
-	err := ioutil.WriteFile("crc32_table_ppc64le.s", b, 0666)
+	err := os.WriteFile("crc32_table_ppc64le.s", b, 0666)
 	if err != nil {
 		fmt.Printf("can't write output: %s\n", err)
 	}
diff --git a/src/html/template/examplefiles_test.go b/src/html/template/examplefiles_test.go
index 60518aee9e..5eb2597464 100644
--- a/src/html/template/examplefiles_test.go
+++ b/src/html/template/examplefiles_test.go
@@ -6,7 +6,6 @@ package template_test
 
 import (
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -20,7 +19,7 @@ type templateFile struct {
 }
 
 func createTestDir(files []templateFile) string {
-	dir, err := ioutil.TempDir("", "template")
+	dir, err := os.MkdirTemp("", "template")
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/html/template/template.go b/src/html/template/template.go
index bc960afe5f..69312d36fd 100644
--- a/src/html/template/template.go
+++ b/src/html/template/template.go
@@ -8,7 +8,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path"
 	"path/filepath"
 	"sync"
@@ -523,7 +523,7 @@ func parseFS(t *Template, fsys fs.FS, patterns []string) (*Template, error) {
 
 func readFileOS(file string) (name string, b []byte, err error) {
 	name = filepath.Base(file)
-	b, err = ioutil.ReadFile(file)
+	b, err = os.ReadFile(file)
 	return
 }
 
diff --git a/src/image/color/palette/gen.go b/src/image/color/palette/gen.go
index f8587db8f3..3243e53981 100644
--- a/src/image/color/palette/gen.go
+++ b/src/image/color/palette/gen.go
@@ -15,8 +15,8 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
+	"os"
 )
 
 var filename = flag.String("output", "palette.go", "output file name")
@@ -43,7 +43,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = ioutil.WriteFile(*filename, data, 0644)
+	err = os.WriteFile(*filename, data, 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/image/gif/reader_test.go b/src/image/gif/reader_test.go
index 29f47b6c08..5eec5ecb4a 100644
--- a/src/image/gif/reader_test.go
+++ b/src/image/gif/reader_test.go
@@ -11,7 +11,7 @@ import (
 	"image/color"
 	"image/color/palette"
 	"io"
-	"io/ioutil"
+	"os"
 	"reflect"
 	"runtime"
 	"runtime/debug"
@@ -424,7 +424,7 @@ func TestDecodeMemoryConsumption(t *testing.T) {
 }
 
 func BenchmarkDecode(b *testing.B) {
-	data, err := ioutil.ReadFile("../testdata/video-001.gif")
+	data, err := os.ReadFile("../testdata/video-001.gif")
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/image/internal/imageutil/gen.go b/src/image/internal/imageutil/gen.go
index bc85c512f9..36de5dc9cc 100644
--- a/src/image/internal/imageutil/gen.go
+++ b/src/image/internal/imageutil/gen.go
@@ -11,7 +11,6 @@ import (
 	"flag"
 	"fmt"
 	"go/format"
-	"io/ioutil"
 	"log"
 	"os"
 )
@@ -36,7 +35,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	if err := ioutil.WriteFile("impl.go", out, 0660); err != nil {
+	if err := os.WriteFile("impl.go", out, 0660); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/src/image/jpeg/reader_test.go b/src/image/jpeg/reader_test.go
index 1e2798c945..bf07fadede 100644
--- a/src/image/jpeg/reader_test.go
+++ b/src/image/jpeg/reader_test.go
@@ -11,7 +11,6 @@ import (
 	"image"
 	"image/color"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"strings"
@@ -118,7 +117,7 @@ func (r *eofReader) Read(b []byte) (n int, err error) {
 
 func TestDecodeEOF(t *testing.T) {
 	// Check that if reader returns final data and EOF at same time, jpeg handles it.
-	data, err := ioutil.ReadFile("../testdata/video-001.jpeg")
+	data, err := os.ReadFile("../testdata/video-001.jpeg")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -189,7 +188,7 @@ func pixString(pix []byte, stride, x, y int) string {
 }
 
 func TestTruncatedSOSDataDoesntPanic(t *testing.T) {
-	b, err := ioutil.ReadFile("../testdata/video-005.gray.q50.jpeg")
+	b, err := os.ReadFile("../testdata/video-005.gray.q50.jpeg")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -493,7 +492,7 @@ func TestExtraneousData(t *testing.T) {
 }
 
 func benchmarkDecode(b *testing.B, filename string) {
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/image/png/reader_test.go b/src/image/png/reader_test.go
index 22c704e5cb..3937685294 100644
--- a/src/image/png/reader_test.go
+++ b/src/image/png/reader_test.go
@@ -11,7 +11,6 @@ import (
 	"image"
 	"image/color"
 	"io"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"strings"
@@ -785,7 +784,7 @@ func TestDimensionOverflow(t *testing.T) {
 }
 
 func benchmarkDecode(b *testing.B, filename string, bytesPerPixel int) {
-	data, err := ioutil.ReadFile(filename)
+	data, err := os.ReadFile(filename)
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/index/suffixarray/gen.go b/src/index/suffixarray/gen.go
index 8c3de553c9..94184d71b6 100644
--- a/src/index/suffixarray/gen.go
+++ b/src/index/suffixarray/gen.go
@@ -11,8 +11,8 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
 	"log"
+	"os"
 	"strings"
 )
 
@@ -20,7 +20,7 @@ func main() {
 	log.SetPrefix("gen: ")
 	log.SetFlags(0)
 
-	data, err := ioutil.ReadFile("sais.go")
+	data, err := os.ReadFile("sais.go")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -64,7 +64,7 @@ func main() {
 		}
 	}
 
-	if err := ioutil.WriteFile("sais2.go", buf.Bytes(), 0666); err != nil {
+	if err := os.WriteFile("sais2.go", buf.Bytes(), 0666); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/src/index/suffixarray/suffixarray_test.go b/src/index/suffixarray/suffixarray_test.go
index a11a98dae0..44c5041535 100644
--- a/src/index/suffixarray/suffixarray_test.go
+++ b/src/index/suffixarray/suffixarray_test.go
@@ -8,8 +8,8 @@ import (
 	"bytes"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"math/rand"
+	"os"
 	"path/filepath"
 	"regexp"
 	"sort"
@@ -498,14 +498,14 @@ func makeText(name string) ([]byte, error) {
 	switch name {
 	case "opticks":
 		var err error
-		data, err = ioutil.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
+		data, err = os.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
 		if err != nil {
 			return nil, err
 		}
 	case "go":
 		err := filepath.WalkDir("../..", func(path string, info fs.DirEntry, err error) error {
 			if err == nil && strings.HasSuffix(path, ".go") && !info.IsDir() {
-				file, err := ioutil.ReadFile(path)
+				file, err := os.ReadFile(path)
 				if err != nil {
 					return err
 				}
diff --git a/src/internal/cpu/cpu_s390x_test.go b/src/internal/cpu/cpu_s390x_test.go
index d910bbe695..ad86858db0 100644
--- a/src/internal/cpu/cpu_s390x_test.go
+++ b/src/internal/cpu/cpu_s390x_test.go
@@ -7,13 +7,13 @@ package cpu_test
 import (
 	"errors"
 	. "internal/cpu"
-	"io/ioutil"
+	"os"
 	"regexp"
 	"testing"
 )
 
 func getFeatureList() ([]string, error) {
-	cpuinfo, err := ioutil.ReadFile("/proc/cpuinfo")
+	cpuinfo, err := os.ReadFile("/proc/cpuinfo")
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/internal/obscuretestdata/obscuretestdata.go b/src/internal/obscuretestdata/obscuretestdata.go
index 06cd1df22c..5ea2cdf5d1 100644
--- a/src/internal/obscuretestdata/obscuretestdata.go
+++ b/src/internal/obscuretestdata/obscuretestdata.go
@@ -10,7 +10,6 @@ package obscuretestdata
 import (
 	"encoding/base64"
 	"io"
-	"io/ioutil"
 	"os"
 )
 
@@ -24,7 +23,7 @@ func DecodeToTempFile(name string) (path string, err error) {
 	}
 	defer f.Close()
 
-	tmp, err := ioutil.TempFile("", "obscuretestdata-decoded-")
+	tmp, err := os.CreateTemp("", "obscuretestdata-decoded-")
 	if err != nil {
 		return "", err
 	}
diff --git a/src/internal/poll/read_test.go b/src/internal/poll/read_test.go
index 2d4ef97da0..598a52ee44 100644
--- a/src/internal/poll/read_test.go
+++ b/src/internal/poll/read_test.go
@@ -5,7 +5,6 @@
 package poll_test
 
 import (
-	"io/ioutil"
 	"os"
 	"runtime"
 	"sync"
@@ -22,7 +21,7 @@ func TestRead(t *testing.T) {
 				go func(p string) {
 					defer wg.Done()
 					for i := 0; i < 100; i++ {
-						if _, err := ioutil.ReadFile(p); err != nil {
+						if _, err := os.ReadFile(p); err != nil {
 							t.Error(err)
 							return
 						}
diff --git a/src/internal/testenv/testenv_windows.go b/src/internal/testenv/testenv_windows.go
index eb8d6ac165..4802b13951 100644
--- a/src/internal/testenv/testenv_windows.go
+++ b/src/internal/testenv/testenv_windows.go
@@ -5,7 +5,6 @@
 package testenv
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sync"
@@ -16,7 +15,7 @@ var symlinkOnce sync.Once
 var winSymlinkErr error
 
 func initWinHasSymlink() {
-	tmpdir, err := ioutil.TempDir("", "symtest")
+	tmpdir, err := os.MkdirTemp("", "symtest")
 	if err != nil {
 		panic("failed to create temp directory: " + err.Error())
 	}
diff --git a/src/internal/trace/gc_test.go b/src/internal/trace/gc_test.go
index 4f9c77041a..9b9771e7b0 100644
--- a/src/internal/trace/gc_test.go
+++ b/src/internal/trace/gc_test.go
@@ -6,8 +6,8 @@ package trace
 
 import (
 	"bytes"
-	"io/ioutil"
 	"math"
+	"os"
 	"testing"
 	"time"
 )
@@ -84,7 +84,7 @@ func TestMMUTrace(t *testing.T) {
 		t.Skip("skipping in -short mode")
 	}
 
-	data, err := ioutil.ReadFile("testdata/stress_1_10_good")
+	data, err := os.ReadFile("testdata/stress_1_10_good")
 	if err != nil {
 		t.Fatalf("failed to read input file: %v", err)
 	}
@@ -126,7 +126,7 @@ func TestMMUTrace(t *testing.T) {
 }
 
 func BenchmarkMMU(b *testing.B) {
-	data, err := ioutil.ReadFile("testdata/stress_1_10_good")
+	data, err := os.ReadFile("testdata/stress_1_10_good")
 	if err != nil {
 		b.Fatalf("failed to read input file: %v", err)
 	}
diff --git a/src/internal/trace/parser_test.go b/src/internal/trace/parser_test.go
index 6d87970157..316220cfa8 100644
--- a/src/internal/trace/parser_test.go
+++ b/src/internal/trace/parser_test.go
@@ -47,7 +47,7 @@ func TestParseCanned(t *testing.T) {
 		if testing.Short() && info.Size() > 10000 {
 			continue
 		}
-		data, err := ioutil.ReadFile(name)
+		data, err := os.ReadFile(name)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/log/syslog/syslog_test.go b/src/log/syslog/syslog_test.go
index 8f472a56b7..207bcf57c1 100644
--- a/src/log/syslog/syslog_test.go
+++ b/src/log/syslog/syslog_test.go
@@ -10,7 +10,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"os"
@@ -88,8 +87,8 @@ func startServer(n, la string, done chan<- string) (addr string, sock io.Closer,
 	} else {
 		// unix and unixgram: choose an address if none given
 		if la == "" {
-			// use ioutil.TempFile to get a name that is unique
-			f, err := ioutil.TempFile("", "syslogtest")
+			// use os.CreateTemp to get a name that is unique
+			f, err := os.CreateTemp("", "syslogtest")
 			if err != nil {
 				log.Fatal("TempFile: ", err)
 			}
diff --git a/src/math/big/link_test.go b/src/math/big/link_test.go
index 2212bd444f..42f9cefca0 100644
--- a/src/math/big/link_test.go
+++ b/src/math/big/link_test.go
@@ -7,7 +7,7 @@ package big
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
+	"os"
 	"os/exec"
 	"path/filepath"
 	"testing"
@@ -27,7 +27,7 @@ func TestLinkerGC(t *testing.T) {
 import _ "math/big"
 func main() {}
 `)
-	if err := ioutil.WriteFile(goFile, file, 0644); err != nil {
+	if err := os.WriteFile(goFile, file, 0644); err != nil {
 		t.Fatal(err)
 	}
 	cmd := exec.Command(goBin, "build", "-o", "x.exe", "x.go")
diff --git a/src/math/bits/make_examples.go b/src/math/bits/make_examples.go
index cd81cd6c4d..1d3ad53fe6 100644
--- a/src/math/bits/make_examples.go
+++ b/src/math/bits/make_examples.go
@@ -11,9 +11,9 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"math/bits"
+	"os"
 )
 
 const header = `// Copyright 2017 The Go Authors. All rights reserved.
@@ -106,7 +106,7 @@ func main() {
 		}
 	}
 
-	if err := ioutil.WriteFile("example_test.go", w.Bytes(), 0666); err != nil {
+	if err := os.WriteFile("example_test.go", w.Bytes(), 0666); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/src/math/bits/make_tables.go b/src/math/bits/make_tables.go
index ff2fe2e385..b068d5e0e3 100644
--- a/src/math/bits/make_tables.go
+++ b/src/math/bits/make_tables.go
@@ -13,8 +13,8 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
+	"os"
 )
 
 var header = []byte(`// Copyright 2017 The Go Authors. All rights reserved.
@@ -40,7 +40,7 @@ func main() {
 		log.Fatal(err)
 	}
 
-	err = ioutil.WriteFile("bits_tables.go", out, 0666)
+	err = os.WriteFile("bits_tables.go", out, 0666)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/mime/multipart/formdata.go b/src/mime/multipart/formdata.go
index 9c42ea8c02..fca5f9e15f 100644
--- a/src/mime/multipart/formdata.go
+++ b/src/mime/multipart/formdata.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"errors"
 	"io"
-	"io/ioutil"
 	"math"
 	"net/textproto"
 	"os"
@@ -91,7 +90,7 @@ func (r *Reader) readForm(maxMemory int64) (_ *Form, err error) {
 		}
 		if n > maxMemory {
 			// too big, write to disk and flush buffer
-			file, err := ioutil.TempFile("", "multipart-")
+			file, err := os.CreateTemp("", "multipart-")
 			if err != nil {
 				return nil, err
 			}
diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go
index 06553636ee..0530c92c2e 100644
--- a/src/net/dnsclient_unix_test.go
+++ b/src/net/dnsclient_unix_test.go
@@ -10,7 +10,6 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path"
 	"reflect"
@@ -235,7 +234,7 @@ type resolvConfTest struct {
 }
 
 func newResolvConfTest() (*resolvConfTest, error) {
-	dir, err := ioutil.TempDir("", "go-resolvconftest")
+	dir, err := os.MkdirTemp("", "go-resolvconftest")
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/net/error_test.go b/src/net/error_test.go
index 7823fdf9d8..556eb8c8d4 100644
--- a/src/net/error_test.go
+++ b/src/net/error_test.go
@@ -13,7 +13,6 @@ import (
 	"internal/poll"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"net/internal/socktest"
 	"os"
 	"runtime"
@@ -730,7 +729,7 @@ func TestFileError(t *testing.T) {
 		t.Skipf("not supported on %s", runtime.GOOS)
 	}
 
-	f, err := ioutil.TempFile("", "go-nettest")
+	f, err := os.CreateTemp("", "go-nettest")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/net/http/filetransport_test.go b/src/net/http/filetransport_test.go
index fdfd44d967..b58888dcb1 100644
--- a/src/net/http/filetransport_test.go
+++ b/src/net/http/filetransport_test.go
@@ -6,7 +6,6 @@ package http
 
 import (
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -24,10 +23,10 @@ func checker(t *testing.T) func(string, error) {
 func TestFileTransport(t *testing.T) {
 	check := checker(t)
 
-	dname, err := ioutil.TempDir("", "")
+	dname, err := os.MkdirTemp("", "")
 	check("TempDir", err)
 	fname := filepath.Join(dname, "foo.txt")
-	err = ioutil.WriteFile(fname, []byte("Bar"), 0644)
+	err = os.WriteFile(fname, []byte("Bar"), 0644)
 	check("WriteFile", err)
 	defer os.Remove(dname)
 	defer os.Remove(fname)
diff --git a/src/net/http/fs_test.go b/src/net/http/fs_test.go
index 2e4751114d..2499051625 100644
--- a/src/net/http/fs_test.go
+++ b/src/net/http/fs_test.go
@@ -79,7 +79,7 @@ func TestServeFile(t *testing.T) {
 
 	var err error
 
-	file, err := ioutil.ReadFile(testFile)
+	file, err := os.ReadFile(testFile)
 	if err != nil {
 		t.Fatal("reading file:", err)
 	}
@@ -379,12 +379,12 @@ func mustRemoveAll(dir string) {
 
 func TestFileServerImplicitLeadingSlash(t *testing.T) {
 	defer afterTest(t)
-	tempDir, err := ioutil.TempDir("", "")
+	tempDir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
 	defer mustRemoveAll(tempDir)
-	if err := ioutil.WriteFile(filepath.Join(tempDir, "foo.txt"), []byte("Hello world"), 0644); err != nil {
+	if err := os.WriteFile(filepath.Join(tempDir, "foo.txt"), []byte("Hello world"), 0644); err != nil {
 		t.Fatalf("WriteFile: %v", err)
 	}
 	ts := httptest.NewServer(StripPrefix("/bar/", FileServer(Dir(tempDir))))
@@ -1177,7 +1177,7 @@ func TestLinuxSendfile(t *testing.T) {
 	filename := fmt.Sprintf("1kb-%d", os.Getpid())
 	filepath := path.Join(os.TempDir(), filename)
 
-	if err := ioutil.WriteFile(filepath, bytes.Repeat([]byte{'a'}, 1<<10), 0755); err != nil {
+	if err := os.WriteFile(filepath, bytes.Repeat([]byte{'a'}, 1<<10), 0755); err != nil {
 		t.Fatal(err)
 	}
 	defer os.Remove(filepath)
diff --git a/src/net/http/request_test.go b/src/net/http/request_test.go
index 689498e19d..29297b0e7b 100644
--- a/src/net/http/request_test.go
+++ b/src/net/http/request_test.go
@@ -12,7 +12,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"mime/multipart"
 	. "net/http"
@@ -1164,7 +1163,7 @@ func BenchmarkFileAndServer_64MB(b *testing.B) {
 }
 
 func benchmarkFileAndServer(b *testing.B, n int64) {
-	f, err := ioutil.TempFile(os.TempDir(), "go-bench-http-file-and-server")
+	f, err := os.CreateTemp(os.TempDir(), "go-bench-http-file-and-server")
 	if err != nil {
 		b.Fatalf("Failed to create temp file: %v", err)
 	}
diff --git a/src/net/http/transfer_test.go b/src/net/http/transfer_test.go
index 1f3d32526d..f0c28b2629 100644
--- a/src/net/http/transfer_test.go
+++ b/src/net/http/transfer_test.go
@@ -10,7 +10,6 @@ import (
 	"crypto/rand"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"strings"
@@ -118,7 +117,7 @@ func TestTransferWriterWriteBodyReaderTypes(t *testing.T) {
 
 	nBytes := int64(1 << 10)
 	newFileFunc := func() (r io.Reader, done func(), err error) {
-		f, err := ioutil.TempFile("", "net-http-newfilefunc")
+		f, err := os.CreateTemp("", "net-http-newfilefunc")
 		if err != nil {
 			return nil, nil, err
 		}
diff --git a/src/net/http/transport_test.go b/src/net/http/transport_test.go
index f22b798035..7f6e0938c2 100644
--- a/src/net/http/transport_test.go
+++ b/src/net/http/transport_test.go
@@ -23,7 +23,6 @@ import (
 	"go/token"
 	"internal/nettrace"
 	"io"
-	"io/ioutil"
 	"log"
 	mrand "math/rand"
 	"net"
@@ -5746,7 +5745,7 @@ func (c *testMockTCPConn) ReadFrom(r io.Reader) (int64, error) {
 func TestTransportRequestWriteRoundTrip(t *testing.T) {
 	nBytes := int64(1 << 10)
 	newFileFunc := func() (r io.Reader, done func(), err error) {
-		f, err := ioutil.TempFile("", "net-http-newfilefunc")
+		f, err := os.CreateTemp("", "net-http-newfilefunc")
 		if err != nil {
 			return nil, nil, err
 		}
diff --git a/src/net/mockserver_test.go b/src/net/mockserver_test.go
index e085f4440b..9faf173679 100644
--- a/src/net/mockserver_test.go
+++ b/src/net/mockserver_test.go
@@ -9,16 +9,15 @@ package net
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"sync"
 	"testing"
 	"time"
 )
 
-// testUnixAddr uses ioutil.TempFile to get a name that is unique.
+// testUnixAddr uses os.CreateTemp to get a name that is unique.
 func testUnixAddr() string {
-	f, err := ioutil.TempFile("", "go-nettest")
+	f, err := os.CreateTemp("", "go-nettest")
 	if err != nil {
 		panic(err)
 	}
diff --git a/src/net/net_windows_test.go b/src/net/net_windows_test.go
index 8aa719f433..a0000950c6 100644
--- a/src/net/net_windows_test.go
+++ b/src/net/net_windows_test.go
@@ -9,7 +9,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"regexp"
@@ -176,7 +175,7 @@ func runCmd(args ...string) ([]byte, error) {
 		}
 		return b
 	}
-	f, err := ioutil.TempFile("", "netcmd")
+	f, err := os.CreateTemp("", "netcmd")
 	if err != nil {
 		return nil, err
 	}
@@ -189,7 +188,7 @@ func runCmd(args ...string) ([]byte, error) {
 			return nil, fmt.Errorf("%s failed: %v: %q", args[0], err, string(removeUTF8BOM(out)))
 		}
 		var err2 error
-		out, err2 = ioutil.ReadFile(f.Name())
+		out, err2 = os.ReadFile(f.Name())
 		if err2 != nil {
 			return nil, err2
 		}
@@ -198,7 +197,7 @@ func runCmd(args ...string) ([]byte, error) {
 		}
 		return nil, fmt.Errorf("%s failed: %v", args[0], err)
 	}
-	out, err = ioutil.ReadFile(f.Name())
+	out, err = os.ReadFile(f.Name())
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/net/unixsock_test.go b/src/net/unixsock_test.go
index 4b2cfc4d62..0b13bf655f 100644
--- a/src/net/unixsock_test.go
+++ b/src/net/unixsock_test.go
@@ -9,7 +9,6 @@ package net
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"runtime"
@@ -417,7 +416,7 @@ func TestUnixUnlink(t *testing.T) {
 		checkExists(t, "after Listen")
 		l.Close()
 		checkNotExists(t, "after Listener close")
-		if err := ioutil.WriteFile(name, []byte("hello world"), 0666); err != nil {
+		if err := os.WriteFile(name, []byte("hello world"), 0666); err != nil {
 			t.Fatalf("cannot recreate socket file: %v", err)
 		}
 		checkExists(t, "after writing temp file")
diff --git a/src/os/error_test.go b/src/os/error_test.go
index 060cf59875..6264ccc966 100644
--- a/src/os/error_test.go
+++ b/src/os/error_test.go
@@ -8,14 +8,13 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
 )
 
 func TestErrIsExist(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ErrIsExist")
+	f, err := os.CreateTemp("", "_Go_ErrIsExist")
 	if err != nil {
 		t.Fatalf("open ErrIsExist tempfile: %s", err)
 		return
@@ -55,7 +54,7 @@ func testErrNotExist(name string) string {
 }
 
 func TestErrIsNotExist(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "_Go_ErrIsNotExist")
+	tmpDir, err := os.MkdirTemp("", "_Go_ErrIsNotExist")
 	if err != nil {
 		t.Fatalf("create ErrIsNotExist tempdir: %s", err)
 		return
@@ -147,12 +146,12 @@ func TestIsPermission(t *testing.T) {
 }
 
 func TestErrPathNUL(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ErrPathNUL\x00")
+	f, err := os.CreateTemp("", "_Go_ErrPathNUL\x00")
 	if err == nil {
 		f.Close()
 		t.Fatal("TempFile should have failed")
 	}
-	f, err = ioutil.TempFile("", "_Go_ErrPathNUL")
+	f, err = os.CreateTemp("", "_Go_ErrPathNUL")
 	if err != nil {
 		t.Fatalf("open ErrPathNUL tempfile: %s", err)
 	}
diff --git a/src/os/exec/exec_test.go b/src/os/exec/exec_test.go
index fc49b8a332..92429f63a5 100644
--- a/src/os/exec/exec_test.go
+++ b/src/os/exec/exec_test.go
@@ -645,7 +645,7 @@ func TestExtraFiles(t *testing.T) {
 		t.Errorf("success trying to fetch %s; want an error", ts.URL)
 	}
 
-	tf, err := ioutil.TempFile("", "")
+	tf, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatalf("TempFile: %v", err)
 	}
diff --git a/src/os/exec/lp_unix_test.go b/src/os/exec/lp_unix_test.go
index e4656cafb8..296480fd04 100644
--- a/src/os/exec/lp_unix_test.go
+++ b/src/os/exec/lp_unix_test.go
@@ -7,13 +7,12 @@
 package exec
 
 import (
-	"io/ioutil"
 	"os"
 	"testing"
 )
 
 func TestLookPathUnixEmptyPath(t *testing.T) {
-	tmp, err := ioutil.TempDir("", "TestLookPathUnixEmptyPath")
+	tmp, err := os.MkdirTemp("", "TestLookPathUnixEmptyPath")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
diff --git a/src/os/exec/lp_windows_test.go b/src/os/exec/lp_windows_test.go
index 59b5f1c2c7..c6f3d5d406 100644
--- a/src/os/exec/lp_windows_test.go
+++ b/src/os/exec/lp_windows_test.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -307,7 +306,7 @@ var lookPathTests = []lookPathTest{
 }
 
 func TestLookPath(t *testing.T) {
-	tmp, err := ioutil.TempDir("", "TestLookPath")
+	tmp, err := os.MkdirTemp("", "TestLookPath")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -504,7 +503,7 @@ var commandTests = []commandTest{
 }
 
 func TestCommand(t *testing.T) {
-	tmp, err := ioutil.TempDir("", "TestCommand")
+	tmp, err := os.MkdirTemp("", "TestCommand")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -529,7 +528,7 @@ func TestCommand(t *testing.T) {
 func buildPrintPathExe(t *testing.T, dir string) string {
 	const name = "printpath"
 	srcname := name + ".go"
-	err := ioutil.WriteFile(filepath.Join(dir, srcname), []byte(printpathSrc), 0644)
+	err := os.WriteFile(filepath.Join(dir, srcname), []byte(printpathSrc), 0644)
 	if err != nil {
 		t.Fatalf("failed to create source: %v", err)
 	}
diff --git a/src/os/fifo_test.go b/src/os/fifo_test.go
index 3041dcfa02..2439192a9d 100644
--- a/src/os/fifo_test.go
+++ b/src/os/fifo_test.go
@@ -11,7 +11,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -31,7 +30,7 @@ func TestFifoEOF(t *testing.T) {
 		t.Skip("skipping on OpenBSD; issue 25877")
 	}
 
-	dir, err := ioutil.TempDir("", "TestFifoEOF")
+	dir, err := os.MkdirTemp("", "TestFifoEOF")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/os_test.go b/src/os/os_test.go
index c5e5cbbb1b..765797f5fb 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -11,7 +11,7 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
+	"os"
 	. "os"
 	osexec "os/exec"
 	"path/filepath"
@@ -155,7 +155,7 @@ func localTmp() string {
 }
 
 func newFile(testName string, t *testing.T) (f *File) {
-	f, err := ioutil.TempFile(localTmp(), "_Go_"+testName)
+	f, err := os.CreateTemp(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempFile %s: %s", testName, err)
 	}
@@ -163,7 +163,7 @@ func newFile(testName string, t *testing.T) (f *File) {
 }
 
 func newDir(testName string, t *testing.T) (name string) {
-	name, err := ioutil.TempDir(localTmp(), "_Go_"+testName)
+	name, err := os.MkdirTemp(localTmp(), "_Go_"+testName)
 	if err != nil {
 		t.Fatalf("TempDir %s: %s", testName, err)
 	}
@@ -616,7 +616,7 @@ func TestReaddirNValues(t *testing.T) {
 	if testing.Short() {
 		t.Skip("test.short; skipping")
 	}
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
@@ -715,7 +715,7 @@ func TestReaddirStatFailures(t *testing.T) {
 		// testing it wouldn't work.
 		t.Skipf("skipping test on %v", runtime.GOOS)
 	}
-	dir, err := ioutil.TempDir("", "")
+	dir, err := os.MkdirTemp("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
@@ -776,7 +776,7 @@ func TestReaddirStatFailures(t *testing.T) {
 
 // Readdir on a regular file should fail.
 func TestReaddirOfFile(t *testing.T) {
-	f, err := ioutil.TempFile("", "_Go_ReaddirOfFile")
+	f, err := os.CreateTemp("", "_Go_ReaddirOfFile")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -867,7 +867,7 @@ func chtmpdir(t *testing.T) func() {
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
@@ -992,12 +992,12 @@ func TestRenameOverwriteDest(t *testing.T) {
 	toData := []byte("to")
 	fromData := []byte("from")
 
-	err := ioutil.WriteFile(to, toData, 0777)
+	err := os.WriteFile(to, toData, 0777)
 	if err != nil {
 		t.Fatalf("write file %q failed: %v", to, err)
 	}
 
-	err = ioutil.WriteFile(from, fromData, 0777)
+	err = os.WriteFile(from, fromData, 0777)
 	if err != nil {
 		t.Fatalf("write file %q failed: %v", from, err)
 	}
@@ -1341,7 +1341,7 @@ func testChtimes(t *testing.T, name string) {
 			// the contents are accessed; also, it is set
 			// whenever mtime is set.
 		case "netbsd":
-			mounts, _ := ioutil.ReadFile("/proc/mounts")
+			mounts, _ := os.ReadFile("/proc/mounts")
 			if strings.Contains(string(mounts), "noatime") {
 				t.Logf("AccessTime didn't go backwards, but see a filesystem mounted noatime; ignoring. Issue 19293.")
 			} else {
@@ -1415,7 +1415,7 @@ func TestChdirAndGetwd(t *testing.T) {
 		case "arm64":
 			dirs = nil
 			for _, d := range []string{"d1", "d2"} {
-				dir, err := ioutil.TempDir("", d)
+				dir, err := os.MkdirTemp("", d)
 				if err != nil {
 					t.Fatalf("TempDir: %v", err)
 				}
@@ -1509,7 +1509,7 @@ func TestProgWideChdir(t *testing.T) {
 		c <- true
 		t.Fatalf("Getwd: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		c <- true
 		t.Fatalf("TempDir: %v", err)
@@ -1576,7 +1576,7 @@ func TestSeek(t *testing.T) {
 		off, err := f.Seek(tt.in, tt.whence)
 		if off != tt.out || err != nil {
 			if e, ok := err.(*PathError); ok && e.Err == syscall.EINVAL && tt.out > 1<<32 && runtime.GOOS == "linux" {
-				mounts, _ := ioutil.ReadFile("/proc/mounts")
+				mounts, _ := os.ReadFile("/proc/mounts")
 				if strings.Contains(string(mounts), "reiserfs") {
 					// Reiserfs rejects the big seeks.
 					t.Skipf("skipping test known to fail on reiserfs; https://golang.org/issue/91")
@@ -1858,7 +1858,7 @@ func TestWriteAt(t *testing.T) {
 		t.Fatalf("WriteAt 7: %d, %v", n, err)
 	}
 
-	b, err := ioutil.ReadFile(f.Name())
+	b, err := os.ReadFile(f.Name())
 	if err != nil {
 		t.Fatalf("ReadFile %s: %v", f.Name(), err)
 	}
@@ -1906,7 +1906,7 @@ func writeFile(t *testing.T, fname string, flag int, text string) string {
 		t.Fatalf("WriteString: %d, %v", n, err)
 	}
 	f.Close()
-	data, err := ioutil.ReadFile(fname)
+	data, err := os.ReadFile(fname)
 	if err != nil {
 		t.Fatalf("ReadFile: %v", err)
 	}
@@ -1948,7 +1948,7 @@ func TestAppend(t *testing.T) {
 
 func TestStatDirWithTrailingSlash(t *testing.T) {
 	// Create new temporary directory and arrange to clean it up.
-	path, err := ioutil.TempDir("", "_TestStatDirWithSlash_")
+	path, err := os.MkdirTemp("", "_TestStatDirWithSlash_")
 	if err != nil {
 		t.Fatalf("TempDir: %s", err)
 	}
@@ -2090,7 +2090,7 @@ func TestLargeWriteToConsole(t *testing.T) {
 func TestStatDirModeExec(t *testing.T) {
 	const mode = 0111
 
-	path, err := ioutil.TempDir("", "go-build")
+	path, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("Failed to create temp directory: %v", err)
 	}
@@ -2159,7 +2159,7 @@ func TestStatStdin(t *testing.T) {
 func TestStatRelativeSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestStatRelativeSymlink")
+	tmpdir, err := os.MkdirTemp("", "TestStatRelativeSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -2249,8 +2249,8 @@ func TestLongPath(t *testing.T) {
 				t.Fatalf("MkdirAll failed: %v", err)
 			}
 			data := []byte("hello world\n")
-			if err := ioutil.WriteFile(sizedTempDir+"/foo.txt", data, 0644); err != nil {
-				t.Fatalf("ioutil.WriteFile() failed: %v", err)
+			if err := os.WriteFile(sizedTempDir+"/foo.txt", data, 0644); err != nil {
+				t.Fatalf("os.WriteFile() failed: %v", err)
 			}
 			if err := Rename(sizedTempDir+"/foo.txt", sizedTempDir+"/bar.txt"); err != nil {
 				t.Fatalf("Rename failed: %v", err)
@@ -2434,7 +2434,7 @@ func TestRemoveAllRace(t *testing.T) {
 
 	n := runtime.GOMAXPROCS(16)
 	defer runtime.GOMAXPROCS(n)
-	root, err := ioutil.TempDir("", "issue")
+	root, err := os.MkdirTemp("", "issue")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/os_unix_test.go b/src/os/os_unix_test.go
index 0bce2989c4..51693fd82a 100644
--- a/src/os/os_unix_test.go
+++ b/src/os/os_unix_test.go
@@ -8,7 +8,7 @@ package os_test
 
 import (
 	"io"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -190,7 +190,7 @@ func TestReaddirRemoveRace(t *testing.T) {
 	}
 	dir := newDir("TestReaddirRemoveRace", t)
 	defer RemoveAll(dir)
-	if err := ioutil.WriteFile(filepath.Join(dir, "some-file"), []byte("hello"), 0644); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "some-file"), []byte("hello"), 0644); err != nil {
 		t.Fatal(err)
 	}
 	d, err := Open(dir)
diff --git a/src/os/os_windows_test.go b/src/os/os_windows_test.go
index e002774844..8d1d1f61b2 100644
--- a/src/os/os_windows_test.go
+++ b/src/os/os_windows_test.go
@@ -13,7 +13,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	osexec "os/exec"
 	"path/filepath"
@@ -31,7 +30,7 @@ import (
 type syscallDescriptor = syscall.Handle
 
 func TestSameWindowsFile(t *testing.T) {
-	temp, err := ioutil.TempDir("", "TestSameWindowsFile")
+	temp, err := os.MkdirTemp("", "TestSameWindowsFile")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -90,7 +89,7 @@ type dirLinkTest struct {
 }
 
 func testDirLinks(t *testing.T, tests []dirLinkTest) {
-	tmpdir, err := ioutil.TempDir("", "testDirLinks")
+	tmpdir, err := os.MkdirTemp("", "testDirLinks")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -115,7 +114,7 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = ioutil.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
+	err = os.WriteFile(filepath.Join(dir, "abc"), []byte("abc"), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -127,7 +126,7 @@ func testDirLinks(t *testing.T, tests []dirLinkTest) {
 			continue
 		}
 
-		data, err := ioutil.ReadFile(filepath.Join(link, "abc"))
+		data, err := os.ReadFile(filepath.Join(link, "abc"))
 		if err != nil {
 			t.Errorf("failed to read abc file: %v", err)
 			continue
@@ -439,7 +438,7 @@ func TestNetworkSymbolicLink(t *testing.T) {
 
 	const _NERR_ServerNotStarted = syscall.Errno(2114)
 
-	dir, err := ioutil.TempDir("", "TestNetworkSymbolicLink")
+	dir, err := os.MkdirTemp("", "TestNetworkSymbolicLink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -600,7 +599,7 @@ func TestStatDir(t *testing.T) {
 }
 
 func TestOpenVolumeName(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestOpenVolumeName")
+	tmpdir, err := os.MkdirTemp("", "TestOpenVolumeName")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -619,7 +618,7 @@ func TestOpenVolumeName(t *testing.T) {
 	want := []string{"file1", "file2", "file3", "gopher.txt"}
 	sort.Strings(want)
 	for _, name := range want {
-		err := ioutil.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
+		err := os.WriteFile(filepath.Join(tmpdir, name), nil, 0777)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -643,7 +642,7 @@ func TestOpenVolumeName(t *testing.T) {
 }
 
 func TestDeleteReadOnly(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestDeleteReadOnly")
+	tmpdir, err := os.MkdirTemp("", "TestDeleteReadOnly")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -804,7 +803,7 @@ func compareCommandLineToArgvWithSyscall(t *testing.T, cmd string) {
 }
 
 func TestCmdArgs(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestCmdArgs")
+	tmpdir, err := os.MkdirTemp("", "TestCmdArgs")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -823,7 +822,7 @@ func main() {
 }
 `
 	src := filepath.Join(tmpdir, "main.go")
-	err = ioutil.WriteFile(src, []byte(prog), 0666)
+	err = os.WriteFile(src, []byte(prog), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -971,14 +970,14 @@ func TestSymlinkCreation(t *testing.T) {
 	}
 	t.Parallel()
 
-	temp, err := ioutil.TempDir("", "TestSymlinkCreation")
+	temp, err := os.MkdirTemp("", "TestSymlinkCreation")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(temp)
 
 	dummyFile := filepath.Join(temp, "file")
-	err = ioutil.WriteFile(dummyFile, []byte(""), 0644)
+	err = os.WriteFile(dummyFile, []byte(""), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1207,7 +1206,7 @@ func mklinkd(t *testing.T, link, target string) {
 }
 
 func TestWindowsReadlink(t *testing.T) {
-	tmpdir, err := ioutil.TempDir("", "TestWindowsReadlink")
+	tmpdir, err := os.MkdirTemp("", "TestWindowsReadlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1272,7 +1271,7 @@ func TestWindowsReadlink(t *testing.T) {
 	testReadlink(t, "reldirlink", "dir")
 
 	file := filepath.Join(tmpdir, "file")
-	err = ioutil.WriteFile(file, []byte(""), 0666)
+	err = os.WriteFile(file, []byte(""), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/path_test.go b/src/os/path_test.go
index 3fe9c5ffa3..b79d958711 100644
--- a/src/os/path_test.go
+++ b/src/os/path_test.go
@@ -6,7 +6,7 @@ package os_test
 
 import (
 	"internal/testenv"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -78,7 +78,7 @@ func TestMkdirAll(t *testing.T) {
 func TestMkdirAllWithSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "TestMkdirAllWithSymlink-")
+	tmpDir, err := os.MkdirTemp("", "TestMkdirAllWithSymlink-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/path_windows_test.go b/src/os/path_windows_test.go
index 862b404362..869db8fd6c 100644
--- a/src/os/path_windows_test.go
+++ b/src/os/path_windows_test.go
@@ -5,7 +5,6 @@
 package os_test
 
 import (
-	"io/ioutil"
 	"os"
 	"strings"
 	"syscall"
@@ -48,7 +47,7 @@ func TestFixLongPath(t *testing.T) {
 }
 
 func TestMkdirAllExtendedLength(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "TestMkdirAllExtendedLength")
+	tmpDir, err := os.MkdirTemp("", "TestMkdirAllExtendedLength")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/pipe_test.go b/src/os/pipe_test.go
index 0593efec75..b98e53845c 100644
--- a/src/os/pipe_test.go
+++ b/src/os/pipe_test.go
@@ -14,7 +14,6 @@ import (
 	"internal/testenv"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	osexec "os/exec"
 	"os/signal"
@@ -161,7 +160,7 @@ func testClosedPipeRace(t *testing.T, read bool) {
 		// Get the amount we have to write to overload a pipe
 		// with no reader.
 		limit = 131073
-		if b, err := ioutil.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
+		if b, err := os.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {
 			if i, err := strconv.Atoi(strings.TrimSpace(string(b))); err == nil {
 				limit = i + 1
 			}
diff --git a/src/os/readfrom_linux_test.go b/src/os/readfrom_linux_test.go
index 00faf39fe5..37047175e6 100644
--- a/src/os/readfrom_linux_test.go
+++ b/src/os/readfrom_linux_test.go
@@ -8,8 +8,8 @@ import (
 	"bytes"
 	"internal/poll"
 	"io"
-	"io/ioutil"
 	"math/rand"
+	"os"
 	. "os"
 	"path/filepath"
 	"strconv"
@@ -173,7 +173,7 @@ func TestCopyFileRange(t *testing.T) {
 	})
 	t.Run("Nil", func(t *testing.T) {
 		var nilFile *File
-		anyFile, err := ioutil.TempFile("", "")
+		anyFile, err := os.CreateTemp("", "")
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/os/removeall_test.go b/src/os/removeall_test.go
index 90efa313ea..3a2f6e3759 100644
--- a/src/os/removeall_test.go
+++ b/src/os/removeall_test.go
@@ -6,7 +6,7 @@ package os_test
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	. "os"
 	"path/filepath"
 	"runtime"
@@ -15,7 +15,7 @@ import (
 )
 
 func TestRemoveAll(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -128,7 +128,7 @@ func TestRemoveAllLarge(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -169,7 +169,7 @@ func TestRemoveAllLongPath(t *testing.T) {
 		t.Fatalf("Could not get wd: %s", err)
 	}
 
-	startPath, err := ioutil.TempDir("", "TestRemoveAllLongPath-")
+	startPath, err := os.MkdirTemp("", "TestRemoveAllLongPath-")
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
@@ -211,7 +211,7 @@ func TestRemoveAllDot(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Could not get wd: %s", err)
 	}
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllDot-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllDot-")
 	if err != nil {
 		t.Fatalf("Could not create TempDir: %s", err)
 	}
@@ -236,7 +236,7 @@ func TestRemoveAllDot(t *testing.T) {
 func TestRemoveAllDotDot(t *testing.T) {
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllDotDot-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllDotDot-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -261,7 +261,7 @@ func TestRemoveAllDotDot(t *testing.T) {
 func TestRemoveReadOnlyDir(t *testing.T) {
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveReadOnlyDir-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveReadOnlyDir-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -298,7 +298,7 @@ func TestRemoveAllButReadOnlyAndPathError(t *testing.T) {
 
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllButReadOnly-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllButReadOnly-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -389,7 +389,7 @@ func TestRemoveUnreadableDir(t *testing.T) {
 
 	t.Parallel()
 
-	tempDir, err := ioutil.TempDir("", "TestRemoveAllButReadOnly-")
+	tempDir, err := os.MkdirTemp("", "TestRemoveAllButReadOnly-")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -413,7 +413,7 @@ func TestRemoveAllWithMoreErrorThanReqSize(t *testing.T) {
 		t.Skip("skipping in short mode")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestRemoveAll-")
+	tmpDir, err := os.MkdirTemp("", "TestRemoveAll-")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/signal/signal_test.go b/src/os/signal/signal_test.go
index 23e33fe82b..8945cbfccb 100644
--- a/src/os/signal/signal_test.go
+++ b/src/os/signal/signal_test.go
@@ -12,7 +12,6 @@ import (
 	"flag"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"runtime"
@@ -304,7 +303,7 @@ func TestDetectNohup(t *testing.T) {
 		os.Remove("nohup.out")
 		out, err := exec.Command("/usr/bin/nohup", os.Args[0], "-test.run=TestDetectNohup", "-check_sighup_ignored").CombinedOutput()
 
-		data, _ := ioutil.ReadFile("nohup.out")
+		data, _ := os.ReadFile("nohup.out")
 		os.Remove("nohup.out")
 		if err != nil {
 			t.Errorf("ran test with -check_sighup_ignored under nohup and it failed: expected success.\nError: %v\nOutput:\n%s%s", err, out, data)
diff --git a/src/os/signal/signal_windows_test.go b/src/os/signal/signal_windows_test.go
index c2b59010fc..4640428587 100644
--- a/src/os/signal/signal_windows_test.go
+++ b/src/os/signal/signal_windows_test.go
@@ -7,7 +7,6 @@ package signal
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -57,7 +56,7 @@ func main() {
 	}
 }
 `
-	tmp, err := ioutil.TempDir("", "TestCtrlBreak")
+	tmp, err := os.MkdirTemp("", "TestCtrlBreak")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
diff --git a/src/os/stat_test.go b/src/os/stat_test.go
index 88b789080e..c409f0ff18 100644
--- a/src/os/stat_test.go
+++ b/src/os/stat_test.go
@@ -7,7 +7,6 @@ package os_test
 import (
 	"internal/testenv"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -186,7 +185,7 @@ func testSymlinkSameFile(t *testing.T, path, link string) {
 func TestDirAndSymlinkStats(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestDirAndSymlinkStats")
+	tmpdir, err := os.MkdirTemp("", "TestDirAndSymlinkStats")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -219,14 +218,14 @@ func TestDirAndSymlinkStats(t *testing.T) {
 func TestFileAndSymlinkStats(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestFileAndSymlinkStats")
+	tmpdir, err := os.MkdirTemp("", "TestFileAndSymlinkStats")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	file := filepath.Join(tmpdir, "file")
-	err = ioutil.WriteFile(file, []byte(""), 0644)
+	err = os.WriteFile(file, []byte(""), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -253,7 +252,7 @@ func TestFileAndSymlinkStats(t *testing.T) {
 func TestSymlinkWithTrailingSlash(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpdir, err := ioutil.TempDir("", "TestSymlinkWithTrailingSlash")
+	tmpdir, err := os.MkdirTemp("", "TestSymlinkWithTrailingSlash")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/timeout_test.go b/src/os/timeout_test.go
index d848e41642..0a39f46333 100644
--- a/src/os/timeout_test.go
+++ b/src/os/timeout_test.go
@@ -11,7 +11,6 @@ package os_test
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"os"
 	"os/signal"
@@ -29,7 +28,7 @@ func TestNonpollableDeadline(t *testing.T) {
 		t.Skipf("skipping on %s", runtime.GOOS)
 	}
 
-	f, err := ioutil.TempFile("", "ostest")
+	f, err := os.CreateTemp("", "ostest")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/os/user/lookup_plan9.go b/src/os/user/lookup_plan9.go
index ea3ce0bc7c..33ae3a6adf 100644
--- a/src/os/user/lookup_plan9.go
+++ b/src/os/user/lookup_plan9.go
@@ -6,7 +6,6 @@ package user
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"syscall"
 )
@@ -23,7 +22,7 @@ func init() {
 }
 
 func current() (*User, error) {
-	ubytes, err := ioutil.ReadFile(userFile)
+	ubytes, err := os.ReadFile(userFile)
 	if err != nil {
 		return nil, fmt.Errorf("user: %s", err)
 	}
diff --git a/src/path/filepath/example_unix_walk_test.go b/src/path/filepath/example_unix_walk_test.go
index 66dc7f6b53..c8a818fd6e 100644
--- a/src/path/filepath/example_unix_walk_test.go
+++ b/src/path/filepath/example_unix_walk_test.go
@@ -9,13 +9,12 @@ package filepath_test
 import (
 	"fmt"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 )
 
 func prepareTestDirTree(tree string) (string, error) {
-	tmpDir, err := ioutil.TempDir("", "")
+	tmpDir, err := os.MkdirTemp("", "")
 	if err != nil {
 		return "", fmt.Errorf("error creating temp directory: %v\n", err)
 	}
diff --git a/src/path/filepath/match_test.go b/src/path/filepath/match_test.go
index 1c3b567fa3..48880ea439 100644
--- a/src/path/filepath/match_test.go
+++ b/src/path/filepath/match_test.go
@@ -7,7 +7,6 @@ package filepath_test
 import (
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	. "path/filepath"
 	"reflect"
@@ -182,7 +181,7 @@ var globSymlinkTests = []struct {
 func TestGlobSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "globsymlink")
+	tmpDir, err := os.MkdirTemp("", "globsymlink")
 	if err != nil {
 		t.Fatal("creating temp dir:", err)
 	}
@@ -268,7 +267,7 @@ func TestWindowsGlob(t *testing.T) {
 		t.Skipf("skipping windows specific test")
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestWindowsGlob")
+	tmpDir, err := os.MkdirTemp("", "TestWindowsGlob")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -302,7 +301,7 @@ func TestWindowsGlob(t *testing.T) {
 		}
 	}
 	for _, file := range files {
-		err := ioutil.WriteFile(Join(tmpDir, file), nil, 0666)
+		err := os.WriteFile(Join(tmpDir, file), nil, 0666)
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/path/filepath/path_test.go b/src/path/filepath/path_test.go
index d760530e26..8616256ac0 100644
--- a/src/path/filepath/path_test.go
+++ b/src/path/filepath/path_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -416,7 +415,7 @@ func chtmpdir(t *testing.T) (restore func()) {
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
@@ -459,7 +458,7 @@ func testWalk(t *testing.T, walk func(string, fs.WalkDirFunc) error, errVisit in
 		defer restore()
 	}
 
-	tmpDir, err := ioutil.TempDir("", "TestWalk")
+	tmpDir, err := os.MkdirTemp("", "TestWalk")
 	if err != nil {
 		t.Fatal("creating temp dir:", err)
 	}
@@ -563,7 +562,7 @@ func touch(t *testing.T, name string) {
 }
 
 func TestWalkSkipDirOnFile(t *testing.T) {
-	td, err := ioutil.TempDir("", "walktest")
+	td, err := os.MkdirTemp("", "walktest")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -613,7 +612,7 @@ func TestWalkSkipDirOnFile(t *testing.T) {
 }
 
 func TestWalkFileError(t *testing.T) {
-	td, err := ioutil.TempDir("", "walktest")
+	td, err := os.MkdirTemp("", "walktest")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -892,7 +891,7 @@ func testEvalSymlinksAfterChdir(t *testing.T, wd, path, want string) {
 func TestEvalSymlinks(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "evalsymlink")
+	tmpDir, err := os.MkdirTemp("", "evalsymlink")
 	if err != nil {
 		t.Fatal("creating temp dir:", err)
 	}
@@ -978,7 +977,7 @@ func TestEvalSymlinksIsNotExist(t *testing.T) {
 func TestIssue13582(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "issue13582")
+	tmpDir, err := os.MkdirTemp("", "issue13582")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -995,7 +994,7 @@ func TestIssue13582(t *testing.T) {
 		t.Fatal(err)
 	}
 	file := filepath.Join(linkToDir, "file")
-	err = ioutil.WriteFile(file, nil, 0644)
+	err = os.WriteFile(file, nil, 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1065,7 +1064,7 @@ var absTests = []string{
 }
 
 func TestAbs(t *testing.T) {
-	root, err := ioutil.TempDir("", "TestAbs")
+	root, err := os.MkdirTemp("", "TestAbs")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -1136,7 +1135,7 @@ func TestAbs(t *testing.T) {
 // We test it separately from all other absTests because the empty string is not
 // a valid path, so it can't be used with os.Stat.
 func TestAbsEmptyString(t *testing.T) {
-	root, err := ioutil.TempDir("", "TestAbsEmptyString")
+	root, err := os.MkdirTemp("", "TestAbsEmptyString")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -1357,7 +1356,7 @@ func TestBug3486(t *testing.T) { // https://golang.org/issue/3486
 }
 
 func testWalkSymlink(t *testing.T, mklink func(target, link string) error) {
-	tmpdir, err := ioutil.TempDir("", "testWalkSymlink")
+	tmpdir, err := os.MkdirTemp("", "testWalkSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1407,14 +1406,14 @@ func TestWalkSymlink(t *testing.T) {
 }
 
 func TestIssue29372(t *testing.T) {
-	tmpDir, err := ioutil.TempDir("", "TestIssue29372")
+	tmpDir, err := os.MkdirTemp("", "TestIssue29372")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpDir)
 
 	path := filepath.Join(tmpDir, "file.txt")
-	err = ioutil.WriteFile(path, nil, 0644)
+	err = os.WriteFile(path, nil, 0644)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1443,7 +1442,7 @@ func TestEvalSymlinksAboveRoot(t *testing.T) {
 
 	t.Parallel()
 
-	tmpDir, err := ioutil.TempDir("", "TestEvalSymlinksAboveRoot")
+	tmpDir, err := os.MkdirTemp("", "TestEvalSymlinksAboveRoot")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1460,7 +1459,7 @@ func TestEvalSymlinksAboveRoot(t *testing.T) {
 	if err := os.Symlink(filepath.Join(evalTmpDir, "a"), filepath.Join(evalTmpDir, "b")); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(evalTmpDir, "a", "file"), nil, 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(evalTmpDir, "a", "file"), nil, 0666); err != nil {
 		t.Fatal(err)
 	}
 
@@ -1491,7 +1490,7 @@ func TestEvalSymlinksAboveRoot(t *testing.T) {
 func TestEvalSymlinksAboveRootChdir(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "TestEvalSymlinksAboveRootChdir")
+	tmpDir, err := os.MkdirTemp("", "TestEvalSymlinksAboveRootChdir")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1514,7 +1513,7 @@ func TestEvalSymlinksAboveRootChdir(t *testing.T) {
 	if err := os.Symlink(subdir, "c"); err != nil {
 		t.Fatal(err)
 	}
-	if err := ioutil.WriteFile(filepath.Join(subdir, "file"), nil, 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(subdir, "file"), nil, 0666); err != nil {
 		t.Fatal(err)
 	}
 
diff --git a/src/path/filepath/path_windows_test.go b/src/path/filepath/path_windows_test.go
index 9309a7dc4d..1c3d84c62d 100644
--- a/src/path/filepath/path_windows_test.go
+++ b/src/path/filepath/path_windows_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -38,7 +37,7 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 		perm    fs.FileMode = 0700
 	)
 
-	tmp, err := ioutil.TempDir("", "testWinSplitListTestIsValid")
+	tmp, err := os.MkdirTemp("", "testWinSplitListTestIsValid")
 	if err != nil {
 		t.Fatalf("TempDir failed: %v", err)
 	}
@@ -63,7 +62,7 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 			return
 		}
 		fn, data := filepath.Join(dd, cmdfile), []byte("@echo "+d+"\r\n")
-		if err = ioutil.WriteFile(fn, data, perm); err != nil {
+		if err = os.WriteFile(fn, data, perm); err != nil {
 			t.Errorf("%d,%d: WriteFile(%#q) failed: %v", ti, i, fn, err)
 			return
 		}
@@ -104,7 +103,7 @@ func testWinSplitListTestIsValid(t *testing.T, ti int, tt SplitListTest,
 func TestWindowsEvalSymlinks(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
-	tmpDir, err := ioutil.TempDir("", "TestWindowsEvalSymlinks")
+	tmpDir, err := os.MkdirTemp("", "TestWindowsEvalSymlinks")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -162,13 +161,13 @@ func TestWindowsEvalSymlinks(t *testing.T) {
 // TestEvalSymlinksCanonicalNames verify that EvalSymlinks
 // returns "canonical" path names on windows.
 func TestEvalSymlinksCanonicalNames(t *testing.T) {
-	tmp, err := ioutil.TempDir("", "evalsymlinkcanonical")
+	tmp, err := os.MkdirTemp("", "evalsymlinkcanonical")
 	if err != nil {
 		t.Fatal("creating temp dir:", err)
 	}
 	defer os.RemoveAll(tmp)
 
-	// ioutil.TempDir might return "non-canonical" name.
+	// os.MkdirTemp might return "non-canonical" name.
 	cTmpName, err := filepath.EvalSymlinks(tmp)
 	if err != nil {
 		t.Errorf("EvalSymlinks(%q) error: %v", tmp, err)
@@ -418,7 +417,7 @@ func TestToNorm(t *testing.T) {
 		{".", `\\localhost\c$`, `\\localhost\c$`},
 	}
 
-	tmp, err := ioutil.TempDir("", "testToNorm")
+	tmp, err := os.MkdirTemp("", "testToNorm")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -429,7 +428,7 @@ func TestToNorm(t *testing.T) {
 		}
 	}()
 
-	// ioutil.TempDir might return "non-canonical" name.
+	// os.MkdirTemp might return "non-canonical" name.
 	ctmp, err := filepath.EvalSymlinks(tmp)
 	if err != nil {
 		t.Fatal(err)
@@ -527,7 +526,7 @@ func TestNTNamespaceSymlink(t *testing.T) {
 		t.Skip("skipping test because mklink command does not support junctions")
 	}
 
-	tmpdir, err := ioutil.TempDir("", "TestNTNamespaceSymlink")
+	tmpdir, err := os.MkdirTemp("", "TestNTNamespaceSymlink")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -564,7 +563,7 @@ func TestNTNamespaceSymlink(t *testing.T) {
 	testenv.MustHaveSymlink(t)
 
 	file := filepath.Join(tmpdir, "file")
-	err = ioutil.WriteFile(file, []byte(""), 0666)
+	err = os.WriteFile(file, []byte(""), 0666)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/runtime/crash_test.go b/src/runtime/crash_test.go
index 5e22b7593e..58ad4f3eba 100644
--- a/src/runtime/crash_test.go
+++ b/src/runtime/crash_test.go
@@ -9,7 +9,6 @@ import (
 	"flag"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -117,7 +116,7 @@ func buildTestProg(t *testing.T, binary string, flags ...string) (string, error)
 	testprog.Lock()
 	defer testprog.Unlock()
 	if testprog.dir == "" {
-		dir, err := ioutil.TempDir("", "go-build")
+		dir, err := os.MkdirTemp("", "go-build")
 		if err != nil {
 			t.Fatalf("failed to create temp directory: %v", err)
 		}
diff --git a/src/runtime/crash_unix_test.go b/src/runtime/crash_unix_test.go
index ebbdbfe5b9..803b031873 100644
--- a/src/runtime/crash_unix_test.go
+++ b/src/runtime/crash_unix_test.go
@@ -10,7 +10,6 @@ import (
 	"bytes"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -85,13 +84,13 @@ func TestCrashDumpsAllThreads(t *testing.T) {
 
 	t.Parallel()
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
 	defer os.RemoveAll(dir)
 
-	if err := ioutil.WriteFile(filepath.Join(dir, "main.go"), []byte(crashDumpsAllThreadsSource), 0666); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, "main.go"), []byte(crashDumpsAllThreadsSource), 0666); err != nil {
 		t.Fatalf("failed to create Go file: %v", err)
 	}
 
diff --git a/src/runtime/debug/heapdump_test.go b/src/runtime/debug/heapdump_test.go
index de1ec27d21..768934d05d 100644
--- a/src/runtime/debug/heapdump_test.go
+++ b/src/runtime/debug/heapdump_test.go
@@ -5,7 +5,6 @@
 package debug_test
 
 import (
-	"io/ioutil"
 	"os"
 	"runtime"
 	. "runtime/debug"
@@ -16,7 +15,7 @@ func TestWriteHeapDumpNonempty(t *testing.T) {
 	if runtime.GOOS == "js" {
 		t.Skipf("WriteHeapDump is not available on %s.", runtime.GOOS)
 	}
-	f, err := ioutil.TempFile("", "heapdumptest")
+	f, err := os.CreateTemp("", "heapdumptest")
 	if err != nil {
 		t.Fatalf("TempFile failed: %v", err)
 	}
@@ -45,7 +44,7 @@ func TestWriteHeapDumpFinalizers(t *testing.T) {
 	if runtime.GOOS == "js" {
 		t.Skipf("WriteHeapDump is not available on %s.", runtime.GOOS)
 	}
-	f, err := ioutil.TempFile("", "heapdumptest")
+	f, err := os.CreateTemp("", "heapdumptest")
 	if err != nil {
 		t.Fatalf("TempFile failed: %v", err)
 	}
diff --git a/src/runtime/debug_test.go b/src/runtime/debug_test.go
index 722e81121f..a0b3f84382 100644
--- a/src/runtime/debug_test.go
+++ b/src/runtime/debug_test.go
@@ -17,7 +17,7 @@ package runtime_test
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"regexp"
 	"runtime"
 	"runtime/debug"
@@ -95,7 +95,7 @@ func debugCallTKill(tid int) error {
 // Linux-specific.
 func skipUnderDebugger(t *testing.T) {
 	pid := syscall.Getpid()
-	status, err := ioutil.ReadFile(fmt.Sprintf("/proc/%d/status", pid))
+	status, err := os.ReadFile(fmt.Sprintf("/proc/%d/status", pid))
 	if err != nil {
 		t.Logf("couldn't get proc tracer: %s", err)
 		return
diff --git a/src/runtime/env_plan9.go b/src/runtime/env_plan9.go
index b7ea863735..f1ac4760a7 100644
--- a/src/runtime/env_plan9.go
+++ b/src/runtime/env_plan9.go
@@ -23,8 +23,8 @@ const (
 // to the (possibly shared) Plan 9 environment, so that Setenv and Getenv
 // conform to the same Posix semantics as on other operating systems.
 // For Plan 9 shared environment semantics, instead of Getenv(key) and
-// Setenv(key, value), one can use ioutil.ReadFile("/env/" + key) and
-// ioutil.WriteFile("/env/" + key, value, 0666) respectively.
+// Setenv(key, value), one can use os.ReadFile("/env/" + key) and
+// os.WriteFile("/env/" + key, value, 0666) respectively.
 //go:nosplit
 func goenvs() {
 	buf := make([]byte, envBufSize)
diff --git a/src/runtime/internal/sys/gengoos.go b/src/runtime/internal/sys/gengoos.go
index 2a4bf0c3b4..9bbc48d94f 100644
--- a/src/runtime/internal/sys/gengoos.go
+++ b/src/runtime/internal/sys/gengoos.go
@@ -9,8 +9,8 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
+	"os"
 	"strconv"
 	"strings"
 )
@@ -18,7 +18,7 @@ import (
 var gooses, goarches []string
 
 func main() {
-	data, err := ioutil.ReadFile("../../../go/build/syslist.go")
+	data, err := os.ReadFile("../../../go/build/syslist.go")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -68,7 +68,7 @@ func main() {
 			}
 			fmt.Fprintf(&buf, "const Goos%s = %d\n", strings.Title(goos), value)
 		}
-		err := ioutil.WriteFile("zgoos_"+target+".go", buf.Bytes(), 0666)
+		err := os.WriteFile("zgoos_"+target+".go", buf.Bytes(), 0666)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -90,7 +90,7 @@ func main() {
 			}
 			fmt.Fprintf(&buf, "const Goarch%s = %d\n", strings.Title(goarch), value)
 		}
-		err := ioutil.WriteFile("zgoarch_"+target+".go", buf.Bytes(), 0666)
+		err := os.WriteFile("zgoarch_"+target+".go", buf.Bytes(), 0666)
 		if err != nil {
 			log.Fatal(err)
 		}
diff --git a/src/runtime/memmove_linux_amd64_test.go b/src/runtime/memmove_linux_amd64_test.go
index d0e8b42a5a..b3ccd907b9 100644
--- a/src/runtime/memmove_linux_amd64_test.go
+++ b/src/runtime/memmove_linux_amd64_test.go
@@ -5,7 +5,6 @@
 package runtime_test
 
 import (
-	"io/ioutil"
 	"os"
 	"reflect"
 	"syscall"
@@ -18,7 +17,7 @@ import (
 func TestMemmoveOverflow(t *testing.T) {
 	t.Parallel()
 	// Create a temporary file.
-	tmp, err := ioutil.TempFile("", "go-memmovetest")
+	tmp, err := os.CreateTemp("", "go-memmovetest")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/runtime/mkduff.go b/src/runtime/mkduff.go
index 6ddf0256e9..94ae75fbfe 100644
--- a/src/runtime/mkduff.go
+++ b/src/runtime/mkduff.go
@@ -27,8 +27,8 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
+	"os"
 )
 
 func main() {
@@ -54,7 +54,7 @@ func gen(arch string, tags, zero, copy func(io.Writer)) {
 	fmt.Fprintln(&buf)
 	copy(&buf)
 
-	if err := ioutil.WriteFile("duff_"+arch+".s", buf.Bytes(), 0644); err != nil {
+	if err := os.WriteFile("duff_"+arch+".s", buf.Bytes(), 0644); err != nil {
 		log.Fatalln(err)
 	}
 }
diff --git a/src/runtime/mkfastlog2table.go b/src/runtime/mkfastlog2table.go
index 305c84a7c1..d650292394 100644
--- a/src/runtime/mkfastlog2table.go
+++ b/src/runtime/mkfastlog2table.go
@@ -12,9 +12,9 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"math"
+	"os"
 )
 
 func main() {
@@ -36,7 +36,7 @@ func main() {
 	}
 	fmt.Fprintln(&buf, "}")
 
-	if err := ioutil.WriteFile("fastlog2table.go", buf.Bytes(), 0644); err != nil {
+	if err := os.WriteFile("fastlog2table.go", buf.Bytes(), 0644); err != nil {
 		log.Fatalln(err)
 	}
 }
diff --git a/src/runtime/mksizeclasses.go b/src/runtime/mksizeclasses.go
index 1a210953a4..b92d1fed5f 100644
--- a/src/runtime/mksizeclasses.go
+++ b/src/runtime/mksizeclasses.go
@@ -35,7 +35,6 @@ import (
 	"fmt"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 )
@@ -65,7 +64,7 @@ func main() {
 	if *stdout {
 		_, err = os.Stdout.Write(out)
 	} else {
-		err = ioutil.WriteFile("sizeclasses.go", out, 0666)
+		err = os.WriteFile("sizeclasses.go", out, 0666)
 	}
 	if err != nil {
 		log.Fatal(err)
diff --git a/src/runtime/pprof/pprof_test.go b/src/runtime/pprof/pprof_test.go
index b807072485..b6ee160e84 100644
--- a/src/runtime/pprof/pprof_test.go
+++ b/src/runtime/pprof/pprof_test.go
@@ -13,7 +13,6 @@ import (
 	"internal/profile"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"math/big"
 	"os"
 	"os/exec"
@@ -1179,7 +1178,7 @@ func TestLabelRace(t *testing.T) {
 // Check that there is no deadlock when the program receives SIGPROF while in
 // 64bit atomics' critical section. Used to happen on mips{,le}. See #20146.
 func TestAtomicLoadStore64(t *testing.T) {
-	f, err := ioutil.TempFile("", "profatomic")
+	f, err := os.CreateTemp("", "profatomic")
 	if err != nil {
 		t.Fatalf("TempFile: %v", err)
 	}
@@ -1208,7 +1207,7 @@ func TestAtomicLoadStore64(t *testing.T) {
 func TestTracebackAll(t *testing.T) {
 	// With gccgo, if a profiling signal arrives at the wrong time
 	// during traceback, it may crash or hang. See issue #29448.
-	f, err := ioutil.TempFile("", "proftraceback")
+	f, err := os.CreateTemp("", "proftraceback")
 	if err != nil {
 		t.Fatalf("TempFile: %v", err)
 	}
diff --git a/src/runtime/pprof/proto.go b/src/runtime/pprof/proto.go
index 8519af6985..bdb4454b6e 100644
--- a/src/runtime/pprof/proto.go
+++ b/src/runtime/pprof/proto.go
@@ -9,7 +9,7 @@ import (
 	"compress/gzip"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"os"
 	"runtime"
 	"strconv"
 	"time"
@@ -575,7 +575,7 @@ func (b *profileBuilder) emitLocation() uint64 {
 // It saves the address ranges of the mappings in b.mem for use
 // when emitting locations.
 func (b *profileBuilder) readMapping() {
-	data, _ := ioutil.ReadFile("/proc/self/maps")
+	data, _ := os.ReadFile("/proc/self/maps")
 	parseProcSelfMaps(data, b.addMapping)
 	if len(b.mem) == 0 { // pprof expects a map entry, so fake one.
 		b.addMappingEntry(0, 0, 0, "", "", true)
diff --git a/src/runtime/pprof/proto_test.go b/src/runtime/pprof/proto_test.go
index 3043d5353f..5eb1aab140 100644
--- a/src/runtime/pprof/proto_test.go
+++ b/src/runtime/pprof/proto_test.go
@@ -10,7 +10,6 @@ import (
 	"fmt"
 	"internal/profile"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"reflect"
@@ -78,7 +77,7 @@ func testPCs(t *testing.T) (addr1, addr2 uint64, map1, map2 *profile.Mapping) {
 	switch runtime.GOOS {
 	case "linux", "android", "netbsd":
 		// Figure out two addresses from /proc/self/maps.
-		mmap, err := ioutil.ReadFile("/proc/self/maps")
+		mmap, err := os.ReadFile("/proc/self/maps")
 		if err != nil {
 			t.Fatal(err)
 		}
diff --git a/src/runtime/race/output_test.go b/src/runtime/race/output_test.go
index 5d0192f67f..986667332f 100644
--- a/src/runtime/race/output_test.go
+++ b/src/runtime/race/output_test.go
@@ -8,7 +8,6 @@ package race_test
 
 import (
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -19,7 +18,7 @@ import (
 )
 
 func TestOutput(t *testing.T) {
-	pkgdir, err := ioutil.TempDir("", "go-build-race-output")
+	pkgdir, err := os.MkdirTemp("", "go-build-race-output")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -34,7 +33,7 @@ func TestOutput(t *testing.T) {
 			t.Logf("test %v runs only on %v, skipping: ", test.name, test.goos)
 			continue
 		}
-		dir, err := ioutil.TempDir("", "go-build")
+		dir, err := os.MkdirTemp("", "go-build")
 		if err != nil {
 			t.Fatalf("failed to create temp directory: %v", err)
 		}
diff --git a/src/runtime/race/testdata/io_test.go b/src/runtime/race/testdata/io_test.go
index 30a121bee4..c5055f7837 100644
--- a/src/runtime/race/testdata/io_test.go
+++ b/src/runtime/race/testdata/io_test.go
@@ -6,7 +6,6 @@ package race_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -18,7 +17,7 @@ import (
 
 func TestNoRaceIOFile(t *testing.T) {
 	x := 0
-	path, _ := ioutil.TempDir("", "race_test")
+	path, _ := os.MkdirTemp("", "race_test")
 	fname := filepath.Join(path, "data")
 	go func() {
 		x = 42
diff --git a/src/runtime/runtime-gdb_test.go b/src/runtime/runtime-gdb_test.go
index e52bd1c4c4..5df8c3c745 100644
--- a/src/runtime/runtime-gdb_test.go
+++ b/src/runtime/runtime-gdb_test.go
@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -170,7 +169,7 @@ func testGdbPython(t *testing.T, cgo bool) {
 	checkGdbVersion(t)
 	checkGdbPython(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -195,7 +194,7 @@ func testGdbPython(t *testing.T, cgo bool) {
 		}
 	}
 
-	err = ioutil.WriteFile(filepath.Join(dir, "main.go"), src, 0644)
+	err = os.WriteFile(filepath.Join(dir, "main.go"), src, 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -404,7 +403,7 @@ func TestGdbBacktrace(t *testing.T) {
 	t.Parallel()
 	checkGdbVersion(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -412,7 +411,7 @@ func TestGdbBacktrace(t *testing.T) {
 
 	// Build the source code.
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(backtraceSource), 0644)
+	err = os.WriteFile(src, []byte(backtraceSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -482,7 +481,7 @@ func TestGdbAutotmpTypes(t *testing.T) {
 		t.Skip("TestGdbAutotmpTypes is too slow on aix/ppc64")
 	}
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -490,7 +489,7 @@ func TestGdbAutotmpTypes(t *testing.T) {
 
 	// Build the source code.
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(autotmpTypeSource), 0644)
+	err = os.WriteFile(src, []byte(autotmpTypeSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -551,7 +550,7 @@ func TestGdbConst(t *testing.T) {
 	t.Parallel()
 	checkGdbVersion(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -559,7 +558,7 @@ func TestGdbConst(t *testing.T) {
 
 	// Build the source code.
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(constsSource), 0644)
+	err = os.WriteFile(src, []byte(constsSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -618,7 +617,7 @@ func TestGdbPanic(t *testing.T) {
 	t.Parallel()
 	checkGdbVersion(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -626,7 +625,7 @@ func TestGdbPanic(t *testing.T) {
 
 	// Build the source code.
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(panicSource), 0644)
+	err = os.WriteFile(src, []byte(panicSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
@@ -696,7 +695,7 @@ func TestGdbInfCallstack(t *testing.T) {
 	t.Parallel()
 	checkGdbVersion(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -704,7 +703,7 @@ func TestGdbInfCallstack(t *testing.T) {
 
 	// Build the source code.
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(InfCallstackSource), 0644)
+	err = os.WriteFile(src, []byte(InfCallstackSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create file: %v", err)
 	}
diff --git a/src/runtime/runtime-lldb_test.go b/src/runtime/runtime-lldb_test.go
index 1e2e5d5be9..c923b872aa 100644
--- a/src/runtime/runtime-lldb_test.go
+++ b/src/runtime/runtime-lldb_test.go
@@ -6,7 +6,6 @@ package runtime_test
 
 import (
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -143,20 +142,20 @@ func TestLldbPython(t *testing.T) {
 
 	checkLldbPython(t)
 
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
 	defer os.RemoveAll(dir)
 
 	src := filepath.Join(dir, "main.go")
-	err = ioutil.WriteFile(src, []byte(lldbHelloSource), 0644)
+	err = os.WriteFile(src, []byte(lldbHelloSource), 0644)
 	if err != nil {
 		t.Fatalf("failed to create src file: %v", err)
 	}
 
 	mod := filepath.Join(dir, "go.mod")
-	err = ioutil.WriteFile(mod, []byte("module lldbtest"), 0644)
+	err = os.WriteFile(mod, []byte("module lldbtest"), 0644)
 	if err != nil {
 		t.Fatalf("failed to create mod file: %v", err)
 	}
@@ -172,7 +171,7 @@ func TestLldbPython(t *testing.T) {
 	}
 
 	src = filepath.Join(dir, "script.py")
-	err = ioutil.WriteFile(src, []byte(lldbScriptSource), 0755)
+	err = os.WriteFile(src, []byte(lldbScriptSource), 0755)
 	if err != nil {
 		t.Fatalf("failed to create script: %v", err)
 	}
diff --git a/src/runtime/signal_windows_test.go b/src/runtime/signal_windows_test.go
index f99857193c..a5a885c2f7 100644
--- a/src/runtime/signal_windows_test.go
+++ b/src/runtime/signal_windows_test.go
@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"fmt"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -28,7 +27,7 @@ func TestVectoredHandlerDontCrashOnLibrary(t *testing.T) {
 	testenv.MustHaveExecPath(t, "gcc")
 	testprog.Lock()
 	defer testprog.Unlock()
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
@@ -93,7 +92,7 @@ func TestLibraryCtrlHandler(t *testing.T) {
 	testenv.MustHaveExecPath(t, "gcc")
 	testprog.Lock()
 	defer testprog.Unlock()
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
diff --git a/src/runtime/syscall_windows_test.go b/src/runtime/syscall_windows_test.go
index a20573eb6a..fb215b3c31 100644
--- a/src/runtime/syscall_windows_test.go
+++ b/src/runtime/syscall_windows_test.go
@@ -10,7 +10,6 @@ import (
 	"internal/syscall/windows/sysdll"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"os/exec"
@@ -446,7 +445,7 @@ func TestStdcallAndCDeclCallbacks(t *testing.T) {
 	if _, err := exec.LookPath("gcc"); err != nil {
 		t.Skip("skipping test: gcc is missing")
 	}
-	tmp, err := ioutil.TempDir("", "TestCDeclCallback")
+	tmp, err := os.MkdirTemp("", "TestCDeclCallback")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -602,14 +601,14 @@ uintptr_t cfunc(callback f, uintptr_t n) {
    return r;
 }
 `
-	tmpdir, err := ioutil.TempDir("", "TestReturnAfterStackGrowInCallback")
+	tmpdir, err := os.MkdirTemp("", "TestReturnAfterStackGrowInCallback")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	srcname := "mydll.c"
-	err = ioutil.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
+	err = os.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -671,14 +670,14 @@ uintptr_t cfunc(uintptr_t a, double b, float c, double d) {
 	return 0;
 }
 `
-	tmpdir, err := ioutil.TempDir("", "TestFloatArgs")
+	tmpdir, err := os.MkdirTemp("", "TestFloatArgs")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	srcname := "mydll.c"
-	err = ioutil.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
+	err = os.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -733,14 +732,14 @@ double cfuncDouble(uintptr_t a, double b, float c, double d) {
 	return 0;
 }
 `
-	tmpdir, err := ioutil.TempDir("", "TestFloatReturn")
+	tmpdir, err := os.MkdirTemp("", "TestFloatReturn")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	srcname := "mydll.c"
-	err = ioutil.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
+	err = os.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -948,7 +947,7 @@ func TestDLLPreloadMitigation(t *testing.T) {
 		t.Skip("skipping test: gcc is missing")
 	}
 
-	tmpdir, err := ioutil.TempDir("", "TestDLLPreloadMitigation")
+	tmpdir, err := os.MkdirTemp("", "TestDLLPreloadMitigation")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -975,7 +974,7 @@ uintptr_t cfunc(void) {
 }
 `
 	srcname := "nojack.c"
-	err = ioutil.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
+	err = os.WriteFile(filepath.Join(tmpdir, srcname), []byte(src), 0)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1035,7 +1034,7 @@ func TestBigStackCallbackSyscall(t *testing.T) {
 		t.Fatal("Abs failed: ", err)
 	}
 
-	tmpdir, err := ioutil.TempDir("", "TestBigStackCallback")
+	tmpdir, err := os.MkdirTemp("", "TestBigStackCallback")
 	if err != nil {
 		t.Fatal("TempDir failed: ", err)
 	}
@@ -1184,14 +1183,14 @@ func BenchmarkOsYield(b *testing.B) {
 }
 
 func BenchmarkRunningGoProgram(b *testing.B) {
-	tmpdir, err := ioutil.TempDir("", "BenchmarkRunningGoProgram")
+	tmpdir, err := os.MkdirTemp("", "BenchmarkRunningGoProgram")
 	if err != nil {
 		b.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)
 
 	src := filepath.Join(tmpdir, "main.go")
-	err = ioutil.WriteFile(src, []byte(benchmarkRunningGoProgram), 0666)
+	err = os.WriteFile(src, []byte(benchmarkRunningGoProgram), 0666)
 	if err != nil {
 		b.Fatal(err)
 	}
diff --git a/src/runtime/testdata/testprog/memprof.go b/src/runtime/testdata/testprog/memprof.go
index 7b134bc078..0392e60f84 100644
--- a/src/runtime/testdata/testprog/memprof.go
+++ b/src/runtime/testdata/testprog/memprof.go
@@ -7,7 +7,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"runtime/pprof"
@@ -31,7 +30,7 @@ func MemProf() {
 
 	runtime.GC()
 
-	f, err := ioutil.TempFile("", "memprof")
+	f, err := os.CreateTemp("", "memprof")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
diff --git a/src/runtime/testdata/testprog/syscalls_linux.go b/src/runtime/testdata/testprog/syscalls_linux.go
index b8ac087626..48f8014237 100644
--- a/src/runtime/testdata/testprog/syscalls_linux.go
+++ b/src/runtime/testdata/testprog/syscalls_linux.go
@@ -7,7 +7,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"syscall"
 )
@@ -17,7 +16,7 @@ func gettid() int {
 }
 
 func tidExists(tid int) (exists, supported bool) {
-	stat, err := ioutil.ReadFile(fmt.Sprintf("/proc/self/task/%d/stat", tid))
+	stat, err := os.ReadFile(fmt.Sprintf("/proc/self/task/%d/stat", tid))
 	if os.IsNotExist(err) {
 		return false, true
 	}
diff --git a/src/runtime/testdata/testprog/timeprof.go b/src/runtime/testdata/testprog/timeprof.go
index 0702885369..1e90af4033 100644
--- a/src/runtime/testdata/testprog/timeprof.go
+++ b/src/runtime/testdata/testprog/timeprof.go
@@ -6,7 +6,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime/pprof"
 	"time"
@@ -17,7 +16,7 @@ func init() {
 }
 
 func TimeProf() {
-	f, err := ioutil.TempFile("", "timeprof")
+	f, err := os.CreateTemp("", "timeprof")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
diff --git a/src/runtime/testdata/testprog/vdso.go b/src/runtime/testdata/testprog/vdso.go
index ef92f48758..d2a300d8f2 100644
--- a/src/runtime/testdata/testprog/vdso.go
+++ b/src/runtime/testdata/testprog/vdso.go
@@ -8,7 +8,6 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime/pprof"
 	"time"
@@ -19,7 +18,7 @@ func init() {
 }
 
 func signalInVDSO() {
-	f, err := ioutil.TempFile("", "timeprofnow")
+	f, err := os.CreateTemp("", "timeprofnow")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
diff --git a/src/runtime/testdata/testprogcgo/pprof.go b/src/runtime/testdata/testprogcgo/pprof.go
index 00f2c42e93..3b73fa0bdd 100644
--- a/src/runtime/testdata/testprogcgo/pprof.go
+++ b/src/runtime/testdata/testprogcgo/pprof.go
@@ -60,7 +60,6 @@ import "C"
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"runtime/pprof"
@@ -75,7 +74,7 @@ func init() {
 func CgoPprof() {
 	runtime.SetCgoTraceback(0, unsafe.Pointer(C.pprofCgoTraceback), nil, nil)
 
-	f, err := ioutil.TempFile("", "prof")
+	f, err := os.CreateTemp("", "prof")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
diff --git a/src/runtime/testdata/testprogcgo/threadpprof.go b/src/runtime/testdata/testprogcgo/threadpprof.go
index 37a2a1ab65..feb774ba59 100644
--- a/src/runtime/testdata/testprogcgo/threadpprof.go
+++ b/src/runtime/testdata/testprogcgo/threadpprof.go
@@ -74,7 +74,6 @@ import "C"
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"runtime/pprof"
@@ -97,7 +96,7 @@ func CgoPprofThreadNoTraceback() {
 }
 
 func pprofThread() {
-	f, err := ioutil.TempFile("", "prof")
+	f, err := os.CreateTemp("", "prof")
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
diff --git a/src/runtime/trace/trace_test.go b/src/runtime/trace/trace_test.go
index 235845df4e..b316eafe4c 100644
--- a/src/runtime/trace/trace_test.go
+++ b/src/runtime/trace/trace_test.go
@@ -10,7 +10,6 @@ import (
 	"internal/race"
 	"internal/trace"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"runtime"
@@ -586,7 +585,7 @@ func saveTrace(t *testing.T, buf *bytes.Buffer, name string) {
 	if !*saveTraces {
 		return
 	}
-	if err := ioutil.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
+	if err := os.WriteFile(name+".trace", buf.Bytes(), 0600); err != nil {
 		t.Errorf("failed to write trace file: %s", err)
 	}
 }
diff --git a/src/runtime/wincallback.go b/src/runtime/wincallback.go
index c022916422..fb452222da 100644
--- a/src/runtime/wincallback.go
+++ b/src/runtime/wincallback.go
@@ -11,7 +11,6 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 )
 
@@ -38,7 +37,7 @@ TEXT runtime·callbackasm(SB),7,$0
 	}
 
 	filename := fmt.Sprintf("zcallback_windows.s")
-	err := ioutil.WriteFile(filename, buf.Bytes(), 0666)
+	err := os.WriteFile(filename, buf.Bytes(), 0666)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
 		os.Exit(2)
@@ -66,7 +65,7 @@ TEXT runtime·callbackasm(SB),NOSPLIT|NOFRAME,$0
 		buf.WriteString("\tB\truntime·callbackasm1(SB)\n")
 	}
 
-	err := ioutil.WriteFile("zcallback_windows_arm.s", buf.Bytes(), 0666)
+	err := os.WriteFile("zcallback_windows_arm.s", buf.Bytes(), 0666)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
 		os.Exit(2)
@@ -82,7 +81,7 @@ package runtime
 
 const cb_max = %d // maximum number of windows callbacks allowed
 `, maxCallback))
-	err := ioutil.WriteFile("zcallback_windows.go", buf.Bytes(), 0666)
+	err := os.WriteFile("zcallback_windows.go", buf.Bytes(), 0666)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)
 		os.Exit(2)
diff --git a/src/sort/genzfunc.go b/src/sort/genzfunc.go
index 66408d26c6..e7eb573737 100644
--- a/src/sort/genzfunc.go
+++ b/src/sort/genzfunc.go
@@ -20,8 +20,8 @@ import (
 	"go/format"
 	"go/parser"
 	"go/token"
-	"io/ioutil"
 	"log"
+	"os"
 	"regexp"
 )
 
@@ -92,7 +92,7 @@ func main() {
 	out.Write(src)
 
 	const target = "zfuncversion.go"
-	if err := ioutil.WriteFile(target, out.Bytes(), 0644); err != nil {
+	if err := os.WriteFile(target, out.Bytes(), 0644); err != nil {
 		log.Fatal(err)
 	}
 }
diff --git a/src/strconv/makeisprint.go b/src/strconv/makeisprint.go
index 1a3248f308..0e6e90a6c6 100644
--- a/src/strconv/makeisprint.go
+++ b/src/strconv/makeisprint.go
@@ -17,8 +17,8 @@ import (
 	"flag"
 	"fmt"
 	"go/format"
-	"io/ioutil"
 	"log"
+	"os"
 	"unicode"
 )
 
@@ -196,7 +196,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = ioutil.WriteFile(*filename, data, 0644)
+	err = os.WriteFile(*filename, data, 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/syscall/dirent_test.go b/src/syscall/dirent_test.go
index f63153340a..7dac98ff4b 100644
--- a/src/syscall/dirent_test.go
+++ b/src/syscall/dirent_test.go
@@ -9,7 +9,6 @@ package syscall_test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"runtime"
@@ -27,7 +26,7 @@ func TestDirent(t *testing.T) {
 		filenameMinSize = 11
 	)
 
-	d, err := ioutil.TempDir("", "dirent-test")
+	d, err := os.MkdirTemp("", "dirent-test")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -36,7 +35,7 @@ func TestDirent(t *testing.T) {
 
 	for i, c := range []byte("0123456789") {
 		name := string(bytes.Repeat([]byte{c}, filenameMinSize+i))
-		err = ioutil.WriteFile(filepath.Join(d, name), nil, 0644)
+		err = os.WriteFile(filepath.Join(d, name), nil, 0644)
 		if err != nil {
 			t.Fatalf("writefile: %v", err)
 		}
@@ -93,7 +92,7 @@ func TestDirentRepeat(t *testing.T) {
 	}
 
 	// Make a directory containing N files
-	d, err := ioutil.TempDir("", "direntRepeat-test")
+	d, err := os.MkdirTemp("", "direntRepeat-test")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -104,7 +103,7 @@ func TestDirentRepeat(t *testing.T) {
 		files = append(files, fmt.Sprintf("file%d", i))
 	}
 	for _, file := range files {
-		err = ioutil.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
+		err = os.WriteFile(filepath.Join(d, file), []byte("contents"), 0644)
 		if err != nil {
 			t.Fatalf("writefile: %v", err)
 		}
diff --git a/src/syscall/exec_linux_test.go b/src/syscall/exec_linux_test.go
index b79dee7525..ac3a5754ae 100644
--- a/src/syscall/exec_linux_test.go
+++ b/src/syscall/exec_linux_test.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/user"
@@ -65,7 +64,7 @@ func skipNoUserNamespaces(t *testing.T) {
 func skipUnprivilegedUserClone(t *testing.T) {
 	// Skip the test if the sysctl that prevents unprivileged user
 	// from creating user namespaces is enabled.
-	data, errRead := ioutil.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
+	data, errRead := os.ReadFile("/proc/sys/kernel/unprivileged_userns_clone")
 	if errRead != nil || len(data) < 1 || data[0] == '0' {
 		t.Skip("kernel prohibits user namespace in unprivileged process")
 	}
@@ -98,7 +97,7 @@ func checkUserNS(t *testing.T) {
 	// On Centos 7 make sure they set the kernel parameter user_namespace=1
 	// See issue 16283 and 20796.
 	if _, err := os.Stat("/sys/module/user_namespace/parameters/enable"); err == nil {
-		buf, _ := ioutil.ReadFile("/sys/module/user_namespace/parameters/enabled")
+		buf, _ := os.ReadFile("/sys/module/user_namespace/parameters/enabled")
 		if !strings.HasPrefix(string(buf), "Y") {
 			t.Skip("kernel doesn't support user namespaces")
 		}
@@ -106,7 +105,7 @@ func checkUserNS(t *testing.T) {
 
 	// On Centos 7.5+, user namespaces are disabled if user.max_user_namespaces = 0
 	if _, err := os.Stat("/proc/sys/user/max_user_namespaces"); err == nil {
-		buf, errRead := ioutil.ReadFile("/proc/sys/user/max_user_namespaces")
+		buf, errRead := os.ReadFile("/proc/sys/user/max_user_namespaces")
 		if errRead == nil && buf[0] == '0' {
 			t.Skip("kernel doesn't support user namespaces")
 		}
@@ -226,7 +225,7 @@ func TestUnshare(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	orig, err := ioutil.ReadFile(path)
+	orig, err := os.ReadFile(path)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -349,7 +348,7 @@ func TestUnshareMountNameSpace(t *testing.T) {
 		t.Skip("kernel prohibits unshare in unprivileged process, unless using user namespace")
 	}
 
-	d, err := ioutil.TempDir("", "unshare")
+	d, err := os.MkdirTemp("", "unshare")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -391,7 +390,7 @@ func TestUnshareMountNameSpaceChroot(t *testing.T) {
 		t.Skip("kernel prohibits unshare in unprivileged process, unless using user namespace")
 	}
 
-	d, err := ioutil.TempDir("", "unshare")
+	d, err := os.MkdirTemp("", "unshare")
 	if err != nil {
 		t.Fatalf("tempdir: %v", err)
 	}
@@ -599,7 +598,7 @@ func testAmbientCaps(t *testing.T, userns bool) {
 	}
 
 	// Copy the test binary to a temporary location which is readable by nobody.
-	f, err := ioutil.TempFile("", "gotest")
+	f, err := os.CreateTemp("", "gotest")
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/syscall/getdirentries_test.go b/src/syscall/getdirentries_test.go
index 2a3419c230..66bb8acba2 100644
--- a/src/syscall/getdirentries_test.go
+++ b/src/syscall/getdirentries_test.go
@@ -8,7 +8,6 @@ package syscall_test
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -29,7 +28,7 @@ func testGetdirentries(t *testing.T, count int) {
 	if count > 100 && testing.Short() && os.Getenv("GO_BUILDER_NAME") == "" {
 		t.Skip("skipping in -short mode")
 	}
-	d, err := ioutil.TempDir("", "getdirentries-test")
+	d, err := os.MkdirTemp("", "getdirentries-test")
 	if err != nil {
 		t.Fatalf("Tempdir: %v", err)
 	}
@@ -41,7 +40,7 @@ func testGetdirentries(t *testing.T, count int) {
 
 	// Make files in the temp directory
 	for _, name := range names {
-		err := ioutil.WriteFile(filepath.Join(d, name), []byte("data"), 0)
+		err := os.WriteFile(filepath.Join(d, name), []byte("data"), 0)
 		if err != nil {
 			t.Fatalf("WriteFile: %v", err)
 		}
diff --git a/src/syscall/mkasm_darwin.go b/src/syscall/mkasm_darwin.go
index f6f75f99f6..1783387a53 100644
--- a/src/syscall/mkasm_darwin.go
+++ b/src/syscall/mkasm_darwin.go
@@ -11,23 +11,22 @@ package main
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"log"
 	"os"
 	"strings"
 )
 
 func main() {
-	in1, err := ioutil.ReadFile("syscall_darwin.go")
+	in1, err := os.ReadFile("syscall_darwin.go")
 	if err != nil {
 		log.Fatalf("can't open syscall_darwin.go: %s", err)
 	}
 	arch := os.Args[1]
-	in2, err := ioutil.ReadFile(fmt.Sprintf("syscall_darwin_%s.go", arch))
+	in2, err := os.ReadFile(fmt.Sprintf("syscall_darwin_%s.go", arch))
 	if err != nil {
 		log.Fatalf("can't open syscall_darwin_%s.go: %s", arch, err)
 	}
-	in3, err := ioutil.ReadFile(fmt.Sprintf("zsyscall_darwin_%s.go", arch))
+	in3, err := os.ReadFile(fmt.Sprintf("zsyscall_darwin_%s.go", arch))
 	if err != nil {
 		log.Fatalf("can't open zsyscall_darwin_%s.go: %s", arch, err)
 	}
@@ -51,7 +50,7 @@ func main() {
 			fmt.Fprintf(&out, "\tJMP\t%s(SB)\n", fn)
 		}
 	}
-	err = ioutil.WriteFile(fmt.Sprintf("zsyscall_darwin_%s.s", arch), out.Bytes(), 0644)
+	err = os.WriteFile(fmt.Sprintf("zsyscall_darwin_%s.s", arch), out.Bytes(), 0644)
 	if err != nil {
 		log.Fatalf("can't write zsyscall_darwin_%s.s: %s", arch, err)
 	}
diff --git a/src/syscall/syscall_linux_test.go b/src/syscall/syscall_linux_test.go
index 92764323ee..153d0efef1 100644
--- a/src/syscall/syscall_linux_test.go
+++ b/src/syscall/syscall_linux_test.go
@@ -9,7 +9,6 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -30,7 +29,7 @@ func chtmpdir(t *testing.T) func() {
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
-	d, err := ioutil.TempDir("", "test")
+	d, err := os.MkdirTemp("", "test")
 	if err != nil {
 		t.Fatalf("chtmpdir: %v", err)
 	}
@@ -160,7 +159,7 @@ func TestLinuxDeathSignal(t *testing.T) {
 
 	// Copy the test binary to a location that a non-root user can read/execute
 	// after we drop privileges
-	tempDir, err := ioutil.TempDir("", "TestDeathSignal")
+	tempDir, err := os.MkdirTemp("", "TestDeathSignal")
 	if err != nil {
 		t.Fatalf("cannot create temporary directory: %v", err)
 	}
@@ -321,7 +320,7 @@ func TestSyscallNoError(t *testing.T) {
 
 	// Copy the test binary to a location that a non-root user can read/execute
 	// after we drop privileges
-	tempDir, err := ioutil.TempDir("", "TestSyscallNoError")
+	tempDir, err := os.MkdirTemp("", "TestSyscallNoError")
 	if err != nil {
 		t.Fatalf("cannot create temporary directory: %v", err)
 	}
@@ -543,7 +542,7 @@ func TestAllThreadsSyscall(t *testing.T) {
 func compareStatus(filter, expect string) error {
 	expected := filter + expect
 	pid := syscall.Getpid()
-	fs, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
+	fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
 	if err != nil {
 		return fmt.Errorf("unable to find %d tasks: %v", pid, err)
 	}
@@ -551,7 +550,7 @@ func compareStatus(filter, expect string) error {
 	foundAThread := false
 	for _, f := range fs {
 		tf := fmt.Sprintf("/proc/%s/status", f.Name())
-		d, err := ioutil.ReadFile(tf)
+		d, err := os.ReadFile(tf)
 		if err != nil {
 			// There are a surprising number of ways this
 			// can error out on linux.  We've seen all of
diff --git a/src/syscall/syscall_unix_test.go b/src/syscall/syscall_unix_test.go
index 1c34ed2c27..7e6a8c9043 100644
--- a/src/syscall/syscall_unix_test.go
+++ b/src/syscall/syscall_unix_test.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"internal/testenv"
 	"io"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/exec"
@@ -79,7 +78,7 @@ func TestFcntlFlock(t *testing.T) {
 	}
 	if os.Getenv("GO_WANT_HELPER_PROCESS") == "" {
 		// parent
-		tempDir, err := ioutil.TempDir("", "TestFcntlFlock")
+		tempDir, err := os.MkdirTemp("", "TestFcntlFlock")
 		if err != nil {
 			t.Fatalf("Failed to create temp dir: %v", err)
 		}
@@ -157,7 +156,7 @@ func TestPassFD(t *testing.T) {
 
 	}
 
-	tempDir, err := ioutil.TempDir("", "TestPassFD")
+	tempDir, err := os.MkdirTemp("", "TestPassFD")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -257,7 +256,7 @@ func passFDChild() {
 	// We make it in tempDir, which our parent will clean up.
 	flag.Parse()
 	tempDir := flag.Arg(0)
-	f, err := ioutil.TempFile(tempDir, "")
+	f, err := os.CreateTemp(tempDir, "")
 	if err != nil {
 		fmt.Printf("TempFile: %v", err)
 		return
diff --git a/src/syscall/syscall_windows_test.go b/src/syscall/syscall_windows_test.go
index d146911073..a9ae54752b 100644
--- a/src/syscall/syscall_windows_test.go
+++ b/src/syscall/syscall_windows_test.go
@@ -5,7 +5,6 @@
 package syscall_test
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -13,7 +12,7 @@ import (
 )
 
 func TestWin32finddata(t *testing.T) {
-	dir, err := ioutil.TempDir("", "go-build")
+	dir, err := os.MkdirTemp("", "go-build")
 	if err != nil {
 		t.Fatalf("failed to create temp directory: %v", err)
 	}
diff --git a/src/testing/testing.go b/src/testing/testing.go
index d4b108a183..80354d5ce8 100644
--- a/src/testing/testing.go
+++ b/src/testing/testing.go
@@ -242,7 +242,6 @@ import (
 	"fmt"
 	"internal/race"
 	"io"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"runtime/debug"
@@ -936,14 +935,14 @@ func (c *common) TempDir() string {
 	if nonExistent {
 		c.Helper()
 
-		// ioutil.TempDir doesn't like path separators in its pattern,
+		// os.MkdirTemp doesn't like path separators in its pattern,
 		// so mangle the name to accommodate subtests.
 		tempDirReplacer.Do(func() {
 			tempDirReplacer.r = strings.NewReplacer("/", "_", "\\", "_", ":", "_")
 		})
 		pattern := tempDirReplacer.r.Replace(c.Name())
 
-		c.tempDir, c.tempDirErr = ioutil.TempDir("", pattern)
+		c.tempDir, c.tempDirErr = os.MkdirTemp("", pattern)
 		if c.tempDirErr == nil {
 			c.Cleanup(func() {
 				if err := os.RemoveAll(c.tempDir); err != nil {
diff --git a/src/text/template/examplefiles_test.go b/src/text/template/examplefiles_test.go
index a15c7a62a3..6534ee3315 100644
--- a/src/text/template/examplefiles_test.go
+++ b/src/text/template/examplefiles_test.go
@@ -6,7 +6,6 @@ package template_test
 
 import (
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"path/filepath"
@@ -20,7 +19,7 @@ type templateFile struct {
 }
 
 func createTestDir(files []templateFile) string {
-	dir, err := ioutil.TempDir("", "template")
+	dir, err := os.MkdirTemp("", "template")
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/text/template/helper.go b/src/text/template/helper.go
index 8269fa28c5..57905e613a 100644
--- a/src/text/template/helper.go
+++ b/src/text/template/helper.go
@@ -9,7 +9,7 @@ package template
 import (
 	"fmt"
 	"io/fs"
-	"io/ioutil"
+	"os"
 	"path"
 	"path/filepath"
 )
@@ -164,7 +164,7 @@ func parseFS(t *Template, fsys fs.FS, patterns []string) (*Template, error) {
 
 func readFileOS(file string) (name string, b []byte, err error) {
 	name = filepath.Base(file)
-	b, err = ioutil.ReadFile(file)
+	b, err = os.ReadFile(file)
 	return
 }
 
diff --git a/src/text/template/link_test.go b/src/text/template/link_test.go
index 4eac7e6755..9dc70dfc0d 100644
--- a/src/text/template/link_test.go
+++ b/src/text/template/link_test.go
@@ -7,7 +7,6 @@ package template_test
 import (
 	"bytes"
 	"internal/testenv"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -40,13 +39,13 @@ func main() {
 	t.Used()
 }
 `
-	td, err := ioutil.TempDir("", "text_template_TestDeadCodeElimination")
+	td, err := os.MkdirTemp("", "text_template_TestDeadCodeElimination")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(td)
 
-	if err := ioutil.WriteFile(filepath.Join(td, "x.go"), []byte(prog), 0644); err != nil {
+	if err := os.WriteFile(filepath.Join(td, "x.go"), []byte(prog), 0644); err != nil {
 		t.Fatal(err)
 	}
 	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", "x.exe", "x.go")
@@ -54,7 +53,7 @@ func main() {
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Fatalf("go build: %v, %s", err, out)
 	}
-	slurp, err := ioutil.ReadFile(filepath.Join(td, "x.exe"))
+	slurp, err := os.ReadFile(filepath.Join(td, "x.exe"))
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/src/time/genzabbrs.go b/src/time/genzabbrs.go
index 1d59ba73ce..9825e705d2 100644
--- a/src/time/genzabbrs.go
+++ b/src/time/genzabbrs.go
@@ -18,9 +18,9 @@ import (
 	"flag"
 	"go/format"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 	"sort"
 	"text/template"
 	"time"
@@ -128,7 +128,7 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	err = ioutil.WriteFile(*filename, data, 0644)
+	err = os.WriteFile(*filename, data, 0644)
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/src/time/tzdata/generate_zipdata.go b/src/time/tzdata/generate_zipdata.go
index d8b47e7878..21357fbf1c 100644
--- a/src/time/tzdata/generate_zipdata.go
+++ b/src/time/tzdata/generate_zipdata.go
@@ -10,7 +10,6 @@ package main
 import (
 	"bufio"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strconv"
 )
@@ -40,7 +39,7 @@ const zipdata = `
 
 func main() {
 	// We should be run in the $GOROOT/src/time/tzdata directory.
-	data, err := ioutil.ReadFile("../../../lib/time/zoneinfo.zip")
+	data, err := os.ReadFile("../../../lib/time/zoneinfo.zip")
 	if err != nil {
 		die("cannot find zoneinfo.zip file: %v", err)
 	}
diff --git a/src/time/zoneinfo_read.go b/src/time/zoneinfo_read.go
index 22a60f3211..c739864815 100644
--- a/src/time/zoneinfo_read.go
+++ b/src/time/zoneinfo_read.go
@@ -546,7 +546,7 @@ func loadLocation(name string, sources []string) (z *Location, firstErr error) {
 }
 
 // readFile reads and returns the content of the named file.
-// It is a trivial implementation of ioutil.ReadFile, reimplemented
+// It is a trivial implementation of os.ReadFile, reimplemented
 // here to avoid depending on io/ioutil or os.
 // It returns an error if name exceeds maxFileSize bytes.
 func readFile(name string) ([]byte, error) {