for ; i < len(s) && i < len(t); i++ {
		sr := s[i]
		tr := t[i]
		if sr|tr >= utf8.RuneSelf {
			goto hasUnicode
		}

		// Easy case.
		if tr == sr {
			continue
		}

		// Make sr < tr to simplify what follows.
		if tr < sr {
			tr, sr = sr, tr
		}
		// ASCII only, sr/tr must be upper/lower case
		if 'A' <= sr && sr <= 'Z' && tr == sr+'a'-'A' {
			continue
		}

			bf := b[:min(int64(len(b)), holeStart-sr.pos)]
			nf, err = tryReadFull(sr.fr, bf)
		} else { // In a hole fragment
			bf := b[:min(int64(len(b)), holeEnd-sr.pos)]
			nf, err = tryReadFull(zeroReader{}, bf)
		}
		b = b[nf:]
		sr.pos += int64(nf)
		if sr.pos >= holeEnd && len(sr.sp) > 1 {
			sr.sp = sr.sp[1:] // Ensure last fragment always remains
		}
	}

	n = len(b0) - len(b)
	switch {

func (sr *scriptedReader) Read(p []byte) (n int, err error) {
	if len(*sr) == 0 {
		panic("too many Read calls on scripted Reader. No steps remain.")
	}
	step := (*sr)[0]
	*sr = (*sr)[1:]
	return step(p)
}

func newScriptedReader(steps ...func(p []byte) (n int, err error)) io.Reader {
	sr := scriptedReader(steps)
	return &sr
}

pkg syscall (darwin-386), const TIOCM_LE = 1
pkg syscall (darwin-386), const TIOCM_RI = 128
pkg syscall (darwin-386), const TIOCM_RNG = 128
pkg syscall (darwin-386), const TIOCM_RTS = 4
pkg syscall (darwin-386), const TIOCM_SR = 16
pkg syscall (darwin-386), const TIOCM_ST = 8
pkg syscall (darwin-386), const TIOCNOTTY = 536900721
pkg syscall (darwin-386), const TIOCNXCL = 536900622
pkg syscall (darwin-386), const TIOCOUTQ = 1074033779

		{sr("a", prefixSize) + "/", "", "", false},
		{sr("a", prefixSize) + "/a", sr("a", prefixSize), "a", true},
		{sr("a", nameSize+1), "", "", false},
		{sr("/", nameSize+1), sr("/", nameSize-1), "/", true},
		{sr("a", prefixSize) + "/" + sr("b", nameSize),
			sr("a", prefixSize), sr("b", nameSize), true},
		{sr("a", prefixSize) + "//" + sr("b", nameSize), "", "", false},

// reads in Scanner.Scan.
type slowReader struct {
	max int
	buf io.Reader
}

func (sr *slowReader) Read(p []byte) (n int, err error) {
	if len(p) > sr.max {
		p = p[0:sr.max]
	}
	return sr.buf.Read(p)
}

// genLine writes to buf a predictable but non-trivial line of text of length
// n, including the terminal newline and an occasional carriage return.

pkg syscall (freebsd-riscv64), const TIOCM_RTS = 4 #53466
pkg syscall (freebsd-riscv64), const TIOCM_RTS ideal-int #53466
pkg syscall (freebsd-riscv64), const TIOCM_SR = 16 #53466
pkg syscall (freebsd-riscv64), const TIOCM_SR ideal-int #53466
pkg syscall (freebsd-riscv64), const TIOCM_ST = 8 #53466
pkg syscall (freebsd-riscv64), const TIOCM_ST ideal-int #53466

pkg debug/elf, const R_LARCH_SOP_PUSH_TLS_TPREL R_LARCH #46229
pkg debug/elf, const R_LARCH_SOP_SL = 33 #46229
pkg debug/elf, const R_LARCH_SOP_SL R_LARCH #46229
pkg debug/elf, const R_LARCH_SOP_SR = 34 #46229
pkg debug/elf, const R_LARCH_SOP_SR R_LARCH #46229
pkg debug/elf, const R_LARCH_SOP_SUB = 32 #46229
pkg debug/elf, const R_LARCH_SOP_SUB R_LARCH #46229
pkg debug/elf, const R_LARCH_SUB16 = 53 #46229

pkg syscall (netbsd-arm64-cgo), const TIOCMSET = 2147775597
pkg syscall (netbsd-arm64-cgo), const TIOCMSET ideal-int
pkg syscall (netbsd-arm64-cgo), const TIOCM_SR = 16
pkg syscall (netbsd-arm64-cgo), const TIOCM_SR ideal-int
pkg syscall (netbsd-arm64-cgo), const TIOCM_ST = 8
pkg syscall (netbsd-arm64-cgo), const TIOCM_ST ideal-int
pkg syscall (netbsd-arm64-cgo), const TIOCNOTTY = 536900721

pkg syscall (darwin-arm64), const TIOCM_RNG ideal-int
pkg syscall (darwin-arm64), const TIOCM_RTS = 4
pkg syscall (darwin-arm64), const TIOCM_RTS ideal-int
pkg syscall (darwin-arm64), const TIOCM_SR = 16
pkg syscall (darwin-arm64), const TIOCM_SR ideal-int
pkg syscall (darwin-arm64), const TIOCM_ST = 8
pkg syscall (darwin-arm64), const TIOCM_ST ideal-int
pkg syscall (darwin-arm64), const TIOCNOTTY = 536900721