http://www.perlmonks.org?node_id=548330


in reply to Re: Params::Validate and Test::MockObject::Extends
in thread Params::Validate and Test::MockObject::Extends

Gee, thanks for the bug report. Oh, you didn't bother sending one!

The XS version actually uses the Perl API's sv_derived_from() function, which apparently is like calling UNIVERSAL::isa(). You might want to submit a doc patch for the Perl core warning people off from using it if you really want to promote "proper" use of isa() and can().