Actually its really weird you bring this up today. Ive encountered this annoyance before and ended up writing my own reftype for Data::Dump::Streamer which returns an Pl_no when the item isn't a ref. And I just a few hours ago wrote on my todo list that this should be included in Scalar::Util as _reftype(). Unfortunately the Pl_no logic doesnt work with blessed as '0' and '' are both valid (but evil) classnames.

Anyway, if you want to avoid this problem you can use DDS::reftype() instead.