I came to the same conclusion. It seems reasonable that if the each() was inside anyone of many CORE/CPAN modules being used that are *.pm (perl source) the message barked would have include the file and line number. It seems reasonable that because this information is not included it comes form a context that cannot provide it. As XS lives in a apace that could be viewed as the layer that bridges both Perl internals to the outside it stands to reason that some parts of this code must use and deal with Lists, arrays, hashes and other things constructs thus arising to the occasion of doing something that smells like an each().