bug#36678: 27.0.50; imenu not working in C++ (maybe because of namespace)

[Paul Smith]

I certainly don't want to discourage anyone from pursuing new features
and capabilities if they want to.

However, my personal opinion is that it's likely not the most
productive use of time.  IMHO cc-mode should continue to focus on
formatting (which is clearly no small task, but which it's very good
at!) and not attempt to also get involved with indexing.

The future (again IMO) for indexing and code introspection is in LSP:
there are very good LSP servers for C++ that are free (I use ccls
personally) and there are also very good LSP clients for Emacs (I use
lsp-mode).  And of course there are LSP servers for many languages
which can all be used with the same LSP client.  Since the servers are
external (ccls is based on clang) they are very fast and can do much,
MUCH more than imenu-type indexing.  I honestly can't imagine working
on a larger codebase without it, anymore.

I don't personally use imenu but a quick search shows that there are
integrations of imenu and lsp-mode available.

Just my $0.02!!