all: update to use os.ReadFile, os.WriteFile, os.CreateTemp, os.MkdirTemp

As part of #42026, these helpers from io/ioutil were moved to os.
(ioutil.TempFile and TempDir became os.CreateTemp and MkdirTemp.)

Update the Go tree to use the preferred names.

As usual, code compiled with the Go 1.4 bootstrap toolchain
and code vendored from other sources is excluded.

ReadDir changes are in a separate CL, because they are not a
simple search and replace.

For #42026.

Change-Id: If318df0216d57e95ea0c4093b89f65e5b0ababb3
Reviewed-on: https://go-review.googlesource.com/c/go/+/266365
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

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)
 		}

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)
 	}

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)
 				}

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)
 //		}
 //	}

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)
 	}

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" {
+	if srcLineNo != "106" {
-		t.Fatalf("line number = %v; want 107", srcLineNo)
+		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)
 	}

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)
 	}

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)
 		}

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)
 	}

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)
 	}
 

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
 		}

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 {

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
 			}

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"

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)
 	}

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)
 	}

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

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
 	}

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.

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)
 	}

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)

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)
 	}

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
 	}

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)
 		}

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)
 	}

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)
 		}
 	}

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)
 	}

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)
 			}

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)
 			}

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())
 

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 {
+	if err := os.WriteFile(path, []byte("ok"), 0777); err != nil {
-		t.Fatalf("ioutil.WriteFile: %v", err)
+		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)
 		}
 

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)
 	}
 }

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) {

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)

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)
 			}

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)
 	}

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
 	}

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)
 	}

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
 				}

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
 	}

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

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)
 	}

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
 	}

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)
 		}

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 ""
 	}

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)
 	}

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)

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

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)
 	}

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)
 	}

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.)

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

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 {

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 {

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
 	}

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)
 	}

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)
 	}

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)
 		}

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()

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
 	}
 

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)
 	}

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)
 		}

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
 		}

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)
 	}

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

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)
 		}

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)

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)
 	}

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)
 	}

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)
 	}

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
 	}

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)
 	}

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)
 	}

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
 

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)
 	}

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)

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
 	}

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)
 	}

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)

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)
 	}

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)
 	}

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))
 	}
 }

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

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)
 	}

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)
 	}

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)
 	}

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

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)
 		}

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)
 	}

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)
 	}

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

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)
 	}

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())
 	}

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)

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
 	}

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")
 	}

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)
 	}
 }

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

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)
 			}

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)