http://qs1969.pair.com?node_id=834163


in reply to CPAN upgrade reports failure due to "make NO isa perl"

You can force install it from cpan I believe, but it might be better not to upgrade system perl blindly as the os vendors might use some unknown black magic while building their perls. If you desperately need a newer version of a Core-only module, install a new local perl instead. But you can just ignore the message from cpan (I do).