type Bad2 interface {
	Bad1
}
</pre>

<h3 id="Map_types">Map types</h3>

<p>
A map is an unordered group of elements of one type, called the
element type, indexed by a set of unique <i>keys</i> of another type,
called the key type.
The value of an uninitialized map is <code>nil</code>.
</p>

<pre class="ebnf">
MapType     = "map" "[" KeyType "]" ElementType .
KeyType     = Type .
</pre>

	KM	R2, R4                 // b92e0024
	KMC	R2, R6                 // b92f0026
	KLMD	R2, R8                 // b93f0028
	KIMD	R0, R4                 // b93e0004
	KDSA	R0, R8                 // b93a0008
	KMA	R2, R6, R4              // b9296024
	KMCTR   R2, R6, R4              // b92d6024

	// vector add and sub instructions
	VAB	V3, V4, V4              // e743400000f3
	VAH	V3, V4, V4              // e743400010f3

the type of the pointer.

Note that values of some Go types, other than the type's zero value,
always include Go pointers. This is true of string, slice, interface,
channel, map, and function types. A pointer type may hold a Go pointer
or a C pointer. Array and struct types may or may not include Go
pointers, depending on the element types. All the discussion below

// preceded and followed by a faulting page.
func dangerousSlice(t *testing.T) []byte {
	pagesize := syscall.Getpagesize()
	b, err := syscall.Mmap(0, 0, 3*pagesize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)
	if err != nil {
		t.Fatalf("mmap failed %s", err)
	}
	err = syscall.Mprotect(b[:pagesize], syscall.PROT_NONE)
	if err != nil {
		t.Fatalf("mprotect low failed %s\n", err)
	}

	//
	// When Writer.WriteHeader is called, the contents of Xattrs will take
	// precedence over those in PAXRecords.
	//
	// Deprecated: Use PAXRecords instead.
	Xattrs map[string]string

	// PAXRecords is a map of PAX extended header records.
	//
	// User-defined records should have keys of the following form:
	//	VENDOR.keyword
	// Where VENDOR is some namespace in all uppercase, and keyword may

The [Map.Clear] method deletes all the entries, resulting in

	addr2lineExePath  string
	addr2linePathErr  error
)

func loadSyms(t *testing.T, dbgExePath string) map[string]string {
	cmd := testenv.Command(t, testenv.GoToolPath(t), "tool", "nm", dbgExePath)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("%v: %v\n%s", cmd, err, string(out))
	}
	syms := make(map[string]string)
	scanner := bufio.NewScanner(bytes.NewReader(out))
	for scanner.Scan() {

	log.SetFlags(0)
	flag.Usage = usage
	flag.Parse()
	args := flag.Args()
	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
		usage()
	}

	var zb bytes.Buffer
	zw := zip.NewWriter(&zb)
	seen := make(map[string]bool)
	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
		if d.IsDir() {
			return nil
		}
		data, err := os.ReadFile(path)
		if err != nil {
			log.Fatal(err)
		}

	// 1.  Grow. This triggers two reallocations in Map.
	maxRune := func(r rune) rune { return unicode.MaxRune }
	m := Map(maxRune, []byte(a))
	expect := tenRunes(unicode.MaxRune)
	if string(m) != expect {
		t.Errorf("growing: expected %q got %q", expect, m)
	}

	// 2. Shrink
	minRune := func(r rune) rune { return 'a' }
	m = Map(minRune, []byte(tenRunes(unicode.MaxRune)))
	expect = a

	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}
	fmt.Printf("%s\n", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
	// Output:
	// 'Gjnf oevyyvt naq gur fyvgul tbcure...
}

func ExampleReader_Len() {
	fmt.Println(bytes.NewReader([]byte("Hi!")).Len())