}

func BenchmarkBufferWriteBlock(b *testing.B) {
	block := make([]byte, 1024)
	for _, n := range []int{1 << 12, 1 << 16, 1 << 20} {
		b.Run(fmt.Sprintf("N%d", n), func(b *testing.B) {
			b.ReportAllocs()
			for i := 0; i < b.N; i++ {
				var bb Buffer
				for bb.Len() < n {
					bb.Write(block)
				}
			}
		})
	}
}

func BenchmarkBufferAppendNoCopy(b *testing.B) {
	var bb Buffer
	bb.Grow(16 << 20)

				Mode:     0666,
				Modified: time.Date(2021, 12, 29, 0, 0, 0, 0, timeZone(0)),
			},
		},
	},
}

func TestReader(t *testing.T) {
	for _, zt := range tests {
		t.Run(zt.Name, func(t *testing.T) {
			readTestZip(t, zt)
		})
	}
}

func readTestZip(t *testing.T, zt ZipTest) {
	var z *Reader
	var err error
	var raw []byte
	if zt.Source != nil {
		rat, size := zt.Source()

func (fakeHash32) Sum32() uint32               { return 0 }

func TestZip64(t *testing.T) {
	if testing.Short() {
		t.Skip("slow test; skipping")
	}
	t.Parallel()
	const size = 1 << 32 // before the "END\n" part
	buf := testZip64(t, size)
	testZip64DirectoryRecordLength(buf, t)
}

func TestZip64EdgeCase(t *testing.T) {
	if testing.Short() {
		t.Skip("slow test; skipping")
	}
	t.Parallel()

The [`asynctimerchan` setting](/pkg/time/#NewTimer) disables this change.
There are no runtime metrics for this change,
This setting may be removed in a future release, Go 1.27 at the earliest.

Go 1.23 changed the mode bits reported by [`os.Lstat`](/pkg/os#Lstat) and [`os.Stat`](/pkg/os#Stat)
for reparse points, which can be controlled with the `winsymlink` setting.

		}, {
			&Header{Name: "world", Mode: 0640, Size: int64(5), Xattrs: map[string]string{"foo": "bar"}},
			[]byte("hello"),
		}},
	}}

	b.Run("Writer", func(b *testing.B) {
		for _, v := range vectors {
			b.Run(v.label, func(b *testing.B) {
				b.ReportAllocs()
				for i := 0; i < b.N; i++ {
					// Writing to io.Discard because we want to

	"go/build"
	"go/parser"
	"go/token"
	"go/types"
	"internal/testenv"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"sort"
	"strconv"
	"strings"
	"sync"
	"testing"
)

const verbose = false

func goCmd() string {
	var exeSuffix string
	if runtime.GOOS == "windows" {
		exeSuffix = ".exe"
	}
	path := filepath.Join(testenv.GOROOT(nil), "bin", "go"+exeSuffix)

x[i], i = 2, 1  // set x[0] = 2, i = 1

x[0], x[0] = 1, 2  // set x[0] = 1, then x[0] = 2 (so x[0] == 2 at end)

x[1], x[3] = 4, 5  // set x[1] = 4, then panic setting x[3] = 5.

type Point struct { x, y int }
var p *Point
x[2], p.x = 6, 7  // set x[2] = 6, then panic setting p.x = 7

i = 2
x = []int{3, 5, 7}
for i, x[i] = range x {  // set i, x[2] = 0, x[0]
	break
}

reparse points changed. Mount points no longer have [ModeSymlink] set,
and reparse points that are not symlinks, Unix sockets, or dedup files
now always have [ModeIrregular] set.
This behavior is controlled by the `winsymlink` setting.
For Go 1.23, it defaults to `winsymlink=1`.

## Tools {#tools}

### Go command {#go-command}

Setting the `GOROOT_FINAL` environment variable no longer has an effect
([#62047](https://go.dev/issue/62047)).
Distributions that install the `go` command to a location other than
`$GOROOT/bin/go` should install a symlink instead of relocating
or copying the `go` binary.

### Vet {#vet}

The `go vet` subcommand now includes the