//
// An empty Dir is treated as ".".
type Dir string

// mapOpenError maps the provided non-nil error from opening name
// to a possibly better non-nil error. In particular, it turns OS-specific errors
// about opening files in non-directories into fs.ErrNotExist. See Issues 18984 and 49552.
func mapOpenError(originalErr error, name string, sep rune, stat func(string) (fs.FileInfo, error)) error {