}
	if strings.HasPrefix(cwd, goroot) {
		subdir, err := filepath.Rel(goroot, cwd)
		if err != nil {
			return "", false, err
		}
		return subdir, true, nil
	}

	for _, p := range filepath.SplitList(build.Default.GOPATH) {
		pabs, err := filepath.EvalSymlinks(p)
		if err != nil {
			return "", false, err
		}
		if !strings.HasPrefix(cwd, pabs) {
			continue
		}
		subdir, err := filepath.Rel(pabs, cwd)

pkg path/filepath, func Match(string, string) (bool, error)
pkg path/filepath, func Rel(string, string) (string, error)
pkg path/filepath, func Split(string) (string, string)
pkg path/filepath, func SplitList(string) []string
pkg path/filepath, func ToSlash(string) string
pkg path/filepath, func VolumeName(string) string
pkg path/filepath, func Walk(string, WalkFunc) error