func oldRustToString(name string, options []Option) (string, bool) {
	max := 0
	for _, o := range options {
		if isMaxLength(o) {
			max = maxLength(o)
		}
	}

	// We know that the string starts with _ZN.
	name = name[3:]

	hexDigit := func(c byte) (byte, bool) {
		switch {
		case c >= '0' && c <= '9':
			return c - '0', true
		case c >= 'a' && c <= 'f':
			return c - 'a' + 10, true
		default:

		return rustToString(name, options)
	}

	// Check for an old-style Rust mangled name.
	// It starts with _ZN and ends with "17h" followed by 16 hex digits
	// followed by "E" followed by an optional suffix starting with "."
	// (which we ignore).
	if strings.HasPrefix(name, "_ZN") {
		rname := name
		if pos := strings.LastIndex(rname, "E."); pos > 0 {
			rname = rname[:pos+1]
		}