return

	case '"', '`': // quoted string
		quote := c
		in.readRune()
		for {
			if in.eof() {
				in.pos = in.token.pos
				in.Error("unexpected EOF in string")
			}
			if in.peekRune() == '\n' {
				in.Error("unexpected newline in string")
			}
			c := in.readRune()
			if c == quote {
				break
			}
			if c == '\\' && quote != '`' {
				if in.eof() {
					in.pos = in.token.pos

			if s.Path.ValuePos < start {
				return groupStarts[i-1]
			}
		}
		return groupStarts[len(groupStarts)-1]
	}

	for _, s := range file.Imports {
		p, err := strconv.Unquote(s.Path.Value)
		if err != nil {
			continue
		}
		if p == "syscall/js" {
			// We don't support examples that import syscall/js,
			// because the package syscall/js is not available in the playground.

		n := names[r]
		check.errorf(n, code, "missing init expr for %s", n.Value)
	}
}

func validatedImportPath(path string) (string, error) {
	s, err := strconv.Unquote(path)
	if err != nil {
		return "", err
	}
	if s == "" {
		return "", fmt.Errorf("empty string")
	}
	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
	for _, r := range s {

		}
	case l > r && (init != nil || r != 1):
		n := s.Names[r]
		check.errorf(n, code, "missing init expr for %s", n)
	}
}

func validatedImportPath(path string) (string, error) {
	s, err := strconv.Unquote(path)
	if err != nil {
		return "", err
	}
	if s == "" {
		return "", fmt.Errorf("empty string")
	}
	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
	for _, r := range s {

		case *ast.GenDecl:
			switch d.Tok {
			case token.IMPORT:
				// imports are handled individually
				for _, spec := range d.Specs {
					if s, ok := spec.(*ast.ImportSpec); ok {
						if import_, err := strconv.Unquote(s.Path.Value); err == nil {
							r.imports[import_] = 1
							var name string
							if s.Name != nil {
								name = s.Name.Name
								if name == "." {
									r.hasDotImp = true
								}
							}

		var err error
		if t, err = strconv.Unquote(t); err != nil {
			return "", err
		}
	} else if strings.ContainsAny(t, "\"'`") {
		// Other quotes are reserved both for possible future expansion
		// and to avoid confusion. For example if someone types 'x'
		// we want that to be a syntax error and not a literal x in literal quotation marks.
		return "", fmt.Errorf("unquoted string cannot contain quote")
	}
	*s = AutoQuote(t)

	escaped := false
	quoted := false
	quote := '\x00'
	i := 0
	for _, rune := range s {
		switch {
		case escaped:
			escaped = false
		case rune == '\\':
			escaped = true
			continue
		case quote != '\x00':
			if rune == quote {
				quote = '\x00'
				continue
			}
		case rune == '"' || rune == '\'':
			quoted = true
			quote = rune
			continue

			line = line[:j]
		}
		if line[len(line)-1] == '\r' {
			line = line[:len(line)-1]
		}
		line = line[len("module "):]

		// If quoted, unquote.
		path = strings.TrimSpace(string(line))
		if path != "" && path[0] == '"' {
			s, err := strconv.Unquote(path)
			if err != nil {
				return ""
			}
			path = s
		}
		return path
	})
}

	data, err := os.ReadFile(file)
	if err != nil {
		return ""
	}
	m := importCommentRE.FindSubmatch(data)
	if m == nil {
		return ""
	}
	path, err := strconv.Unquote(string(m[1]))
	if err != nil {
		return ""
	}
	return path
}

// WriteOpts control the behavior of WriteGoMod.
type WriteOpts struct {
	DropToolchain     bool // go get toolchain@none

				// this as line continuation.”
			} else {
				flag = append(flag, c)
			}
			escaped = false
			continue
		}

		if quote != 0 && c == quote {
			quote = 0
			continue
		}
		switch quote {
		case '\'':
			// “preserve the literal value of each character”
			flag = append(flag, c)
			continue
		case '"':