Perl's DOES defaults to ISA since Perl can't distinguish between base classes and roles/traits.

Perl 5's DOES defaults to isa() because I wrote it that way, because I understand Liskov's substitution principle.

If DOES means "Can I treat this invocant as if it were an object of that type?" (and it does), then clearly an object which is an instance of that type or a subclass of that type should return a true value for that question.

In reply to Re^4: Introspection of Moose/Mouse attributes fails to find native trait with `does` by chromatic
in thread Introspection of Moose/Mouse attributes fails to find native trait with `does` by Your Mother

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