DUChain support of defaulted/deleted functions again

[Wolfgang Bangerth]

> If you enable "highlight semantic problems" in configure -> language
> support, the use of foo() will be squiggly-underlined in yellow and you'll
> see the error message on hover or in the problems toolview.
> 
> > Tracking whether a special function is deleted only makes
> > sense if KDevelop were going to take action if a user was going to use
> > this function and remind her that that is an error -- but I tend to think
> > that this would be better left to the compiler.
> 
> I disagree wholeheartedly: One of the big advantages of KDevelop for me and
> lots of other users I've spoken with on conventions and at work, is that it
> reduces the number of required compile cycles. If we can spot the error via
> our semantic analysis, we can report it ASAP and make the "compile -> darn,
> error -> fix -> recompile" superfluous.

That's a fair point, and I do like KDevelop for that, no doubt. I guess I 
should just spend my energy filing bug reports about things where KDevelop 
currently gets the parsing wrong even though the code is legit and compiles 
just fine :-)

(Yesterday's find in this regard is 
https://bugs.kde.org/show_bug.cgi?id=276090 )

Best
 W.

-------------------------------------------------------------------------
Wolfgang Bangerth                email:            bangerth at math.tamu.edu
                                 www: http://www.math.tamu.edu/~bangerth/