bug#20629: 25.0.50; Regression: TAGS broken, can't find anything in C++ files.

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 23 May 2015 18:56:04 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 20629@debbugs.gnu.org
> 
> > Does the patch below give good results in real-life C++ usage?
> > 
> > Please also consider whether this change could cause trouble in other
> > C++ use cases.  (I've ran the modified version on the etags test
> > suite, and didn't spot any problems in the differences with the
> > previous results, but I don't consider myself an expert on C++
> > syntax.)
> 
> I see that etags deliberately produces explicitly named tags of the
> form CLASS::MEMBER, whenever it sees a declaration of MEMBER inside a
> class declaration of CLASS.  Why is that useful?  It is another
> instance that defeats the change which removed tag-symbol-match-p from
> the "order" functions used by etags.el when invoked from xref.  Does
> anyone see a problem with removing this feature from etags?

I've attempted to fix this and other underlying problems by suitable
changes in etags.c in commit 9c66c5a.  The feature whereby etags
qualifies class members by their class names in TAGS is now optional,
off by default, which creates tag names that are more accurate, and
xref should now work much better with C-like object-oriented
languages.

Please give it a try, including in real-life use cases.  I'm not yet
closing the bug on account of possible complications.

Thanks.