I don't think that workaround will work

Oops, my bad. Indeed, your suggested mechanism should work far better.

Incidentally, this warning is removed as of 5.8.1, but is still in bleadperl; is this intentional?

I would expect so, but I'd have to check back through the voluminous discussions around this to be certain. I think the intention is that in 5.10 the various v-string syntaxes will generate a version object, and require VERSION; will simply DTRT.

Hugo