One should only use inheritance on classes that were designed to be inheritted from. Bit::Vector appears to have not only not been designed to support inheritance, but actually designed to not support inheritance. So I agree that toma should stop fighting it.

Plus inheritance is a bit of blunt weapon, especially in Perl. Unless you and/or Bit::Vector go out of your way to prevent it, (to take just one example) any non-method utility subroutines must be very carefully named (and Bit::Vector probably doesn't know about your names and so can't avoid accidentally using them in the next release).

There is even a module on CPAN that makes dispatching the Bit::Vector method calls easy (sorry, I don't recall the name, though).