Part of the issue is that LSP's Xref activation function just returns
"'xref-lsp", the symbol that is specializes it's xref methods on,
without any checking -- which is fairly common from what I see. But if
that fails, Xref won't go on searching, even though the next backend
could have more to offer.
Before writing this message, I was fairly sure that there were some
discussions on this issue, but I couldn't find them in the archives
anymore, so just to be safe, I re-iterated the problem.
What I would want to know, is if there have been discussion on this
issue, what the status is, and if not what would have to be done. I can
imagine, that falling back onto the next backend isn't always desirable
(especially if etags is next, and it demands a TAGS file that doesn't
exist).