Comment 2 for bug 1297147

This bug is also in POSIX:

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/rm.html

If either of the files dot or dot-dot are specified as the basename portion of an operand (that is, the final pathname component) or if an operand resolves to the root directory, rm shall write a diagnostic message to standard error and do nothing more with such operands.

But the paragraph is not considering -r and -f options.