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

[Dmitry Gutov <dgutov@yandex.ru>]

On 05/28/2015 02:35 PM, Francesco Potortì wrote:
> Given that in the 15+ years since implicit tags where
> introduced the trade-offs between disk space and CPU time have changed,
> it could maybe make sense to remove the implicit tag concept altogether,
> and only have explicit tags, should this make things easier.

Maybe so, but:

> In class-based programs,
> like C++, it can be useful to provide a fully-qualified name for an
> identifier, so there is a class::id tag.  Here again, it may make sense
> to tag all entries, if it makes TAGS parsing easier or more accurate.

The question at hand is how Emacs should go from a non-qualified tag 
name (because it's a method call in the buffer, and we don't know which 
class the object belongs to) to the tag location. Either we use some 
implicit matching, or each method tag should have two entries: a 
qualified one, and a non-qualified one.