{"x \xc0\xc0 ", "x \xc0\xc0"},
	{"x ☺\xc0\xc0 ", "x ☺\xc0\xc0"},
	{"x ☺ ", "x ☺"},
}

func tenRunes(ch rune) string {
	r := make([]rune, 10)
	for i := range r {
		r[i] = ch
	}
	return string(r)
}

// User-defined self-inverse mapping function
func rot13(r rune) rune {
	step := rune(13)
	if r >= 'a' && r <= 'z' {
		return ((r - 'a' + step) % 26) + 'a'
	}
	if r >= 'A' && r <= 'Z' {

The [RuneLen] function returns the number of 16-bit words in
the UTF-16 encoding of the rune. It returns -1 if the rune

				switch u.Kind() {
				case types.Byte, types.Rune, types.UntypedRune:
					continue
				}
				V0 = vt
				break
			}
		}

		if V0 == nil {
			// No source types are non-byte or rune integer types.
			return
		}

		convertibleToRune := true // if true, we can suggest a fix
		for _, t := range vtypes {
			if !types.ConvertibleTo(t, types.Typ[types.Rune]) {
				convertibleToRune = false
				break

	// the closure once per rune.
	prev := ' '
	return Map(
		func(r rune) rune {
			if isSeparator(prev) {
				prev = r
				return unicode.ToTitle(r)
			}
			prev = r
			return r
		},
		s)
}

// TrimLeftFunc returns a slice of the string s with all leading
// Unicode code points c satisfying f(c) removed.
func TrimLeftFunc(s string, f func(rune) bool) string {
	i := indexFunc(s, f, false)

	}
	copy(b, s)
	return b
}

func stringtoslicerune(buf *[tmpStringBufSize]rune, s string) []rune {
	// two passes.
	// unlike slicerunetostring, no race because strings are immutable.
	n := 0
	for range s {
		n++
	}

	var a []rune
	if buf != nil && n <= len(buf) {
		*buf = [tmpStringBufSize]rune{}
		a = buf[:n]
	} else {
		a = rawruneslice(n)
	}

	n = 0

	Flag(c int) bool
}

// Formatter is implemented by any value that has a Format method.
// The implementation controls how [State] and rune are interpreted,
// and may call [Sprint] or [Fprint](f) etc. to generate its output.
type Formatter interface {
	Format(f State, verb rune)
}

// Stringer is implemented by any value that has a String method,
// which defines the “native” format for that value.

		{NewTypeName(nopos, pkg, "int32", Typ[Int32]), true},              // type name is declared in user-defined package (outside Universe)
		{NewTypeName(nopos, nil, "rune", Typ[Rune]), true},                // type name refers to basic type rune which is an alias already
		{t5, false}, // type name refers to type parameter and vice versa
	} {
		check(test.name, test.alias)
	}
}

		{NewTypeName(nopos, pkg, "int32", Typ[Int32]), true},              // type name is declared in user-defined package (outside Universe)
		{NewTypeName(nopos, nil, "rune", Typ[Rune]), true},                // type name refers to basic type rune which is an alias already
		{t5, false}, // type name refers to type parameter and vice versa
	} {
		check(test.name, test.alias)
	}
}

	}

	// 5. Drop
	dropNotLatin := func(r rune) rune {
		if unicode.Is(unicode.Latin, r) {
			return r
		}
		return -1
	}
	m = Map(dropNotLatin, []byte("Hello, 세계"))
	expect = "Hello"
	if string(m) != expect {
		t.Errorf("drop: expected %q got %q", expect, m)
	}

	// 6. Invalid rune
	invalidRune := func(r rune) rune {
		return utf8.MaxRune + 1
	}

			b.ReportMetric(float64(latencies[len(latencies)*99/100]), "p99-ns")
		}
		return func(b *testing.B) {
			b.Run("idle", runOne)

			b.Run("loaded", func(b *testing.B) {
				stop := applyGCLoad(b)
				runOne(b)
				// Make sure to stop the timer before we wait! The load created above
				// is very heavy-weight and not easy to stop, so we could end up