//
// PathUnescape is identical to [QueryUnescape] except that it does not
// unescape '+' to ' ' (space).
func PathUnescape(s string) (string, error) {
	return unescape(s, encodePathSegment)
}

// unescape unescapes a string; the mode specifies
// which section of the URL string is being unescaped.
func unescape(s string, mode encoding) (string, error) {
	// Count %, check that they're well-formed.
	n := 0

// and therefore which escaped quote character is permitted.
// If set to a single quote, it permits the sequence \' and disallows unescaped '.
// If set to a double quote, it permits \" and disallows unescaped ".
// If set to zero, it does not permit either escape and allows both quote characters to appear unescaped.
func UnquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) {
	// easy cases
	if len(s) == 0 {

			switch i {
			case 0x5c:
				output = strings.ReplaceAll(output, `\`, `/`)
			case 0x7e:
				output = strings.ReplaceAll(output, `%7e`, `~`)
			}
			if err != nil {
				t.Errorf("failed to unescape percent encoded path %s: %v", input, err)
			}
		}
		percentEncodedCases = append(percentEncodedCases, expect{in: input, out: output})
	}
	framework.NewTest(t).
		Run(func(t framework.TestContext) {

func ParseLinkFuncName(name string) (pkg, sym string, err error) {
	pkg, sym = splitPkg(name)
	if pkg == "" {
		return "", "", fmt.Errorf("no package path in name")
	}

	pkg, err = objabi.PrefixToPath(pkg) // unescape
	if err != nil {
		return "", "", fmt.Errorf("malformed package path: %v", err)
	}

	return pkg, sym, nil
}

// Borrowed from x/mod.
func modPathOK(r rune) bool {
	if r < utf8.RuneSelf {

client or server to have an empty Content-Length header.
This behavior is controlled by the `httplaxcontentlength` setting.

Go 1.22 changed the behavior of ServeMux to accept extended
patterns and unescape both patterns and request paths by segment.
This behavior can be controlled by the
[`httpmuxgo121` setting](/pkg/net/http/#ServeMux).

Go 1.22 added the [Alias type](/pkg/go/types#Alias) to [go/types](/pkg/go/types)

//
//go:nosplit
//go:nocheckptr
func NoEscape(p unsafe.Pointer) unsafe.Pointer {
	x := uintptr(p)
	return unsafe.Pointer(x ^ 0)
}

var alwaysFalse bool
var escapeSink any

// Escape forces any pointers in x to escape to the heap.
func Escape[T any](x T) T {
	if alwaysFalse {
		escapeSink = x
	}
	return x

// The time must be a quoted string in the RFC 3339 format.
func (t *Time) UnmarshalJSON(data []byte) error {
	if string(data) == "null" {
		return nil
	}
	// TODO(https://go.dev/issue/47353): Properly unescape a JSON string.
	if len(data) < 2 || data[0] != '"' || data[len(data)-1] != '"' {
		return errors.New("Time.UnmarshalJSON: input is not a JSON string")
	}
	data = data[len(`"`) : len(data)-len(`"`)]
	var err error

	if bn == nil {
		return false
	}
	*bnp = bn
	return true
}

// noescape hides a pointer from escape analysis.  noescape is
// the identity function but escape analysis doesn't think the
// output depends on the input.  noescape is inlined and currently
// compiles down to zero instructions.
// USE CAREFULLY!
//
//go:nosplit
func noescape(p unsafe.Pointer) unsafe.Pointer {
	x := uintptr(p)
	return unsafe.Pointer(x ^ 0)

			if runtime.MapBucketsPointerIsNil(localMap) {
				t.Errorf("no escape: buckets pointer is nil for non-escaping map")
			}
			for i := 0; i < tt.n; i++ {
				localMap[i] = i
			}
			if got := runtime.MapBucketsCount(localMap); got != tt.noescape {
				t.Errorf("no escape: n=%d want %d buckets, got %d", tt.n, tt.noescape, got)
			}
			escapingMap := runtime.Escape(map[int]int{})

}

func (b *Builder) copyCheck() {
	if b.addr == nil {
		// This hack works around a failing of Go's escape analysis
		// that was causing b to escape and be heap allocated.
		// See issue 23382.
		// TODO: once issue 7921 is fixed, this should be reverted to
		// just "b.addr = b".
		b.addr = (*Builder)(abi.NoEscape(unsafe.Pointer(b)))
	} else if b.addr != b {
		panic("strings: illegal use of non-zero Builder copied by value")
	}