More: better document two-stage name lookup & template base classes

[Wolfgang Bangerth <bangerth at ices dot utexas dot edu>]

Gerald,

> Suggestion 1: Add a reference from <http://gcc.gnu.org/bugs.html#nonbugs>
> to <http://gcc.gnu.org/onlinedocs/gcc/C---Misunderstandings.html>.

I'll not have time for the next three weeks -- can you take care of this part?


> Suggestion 2: Add the following reduced variant of my example to
> trouble.texi, together with the (updated) error message.

Something like this is now in the manual.


> Suggestion 3: Change the error message to
>
>   there are no arguments to `f' that depend on a template parameter, so
>   a declaration of `f' must be available; if `f' is a member of a base
>   class, you can write `this->f' instead.

I don't know whether we want this. The text of the message is now in the 
manual, i.e. when you look for more information, you'll find quite a long 
explanation of the problem and how to make the code valid. I don't think we 
should try to do that in the error message.

In any case I'm not qualified to do anything about this one anyway.


> Given that the error message referred me to -fpermissive, I had checked
> the corresponding documentation but only found the following:
>
>   `-fpermissive'
>      Downgrade some diagnostics about nonconformant code from errors to
>      warnings.  Thus, using `-fpermissive' will allow some
>      nonconforming code to compile.
>
> Even a short and incomplete list of things -fpermissive makes acceptable
> input would have been very helpful.
>
> Suggestion 4: Add such a short list of changes you are aware of and
> consider relevant to the documentation of -fpermissive;

That might make sense, although I'm not too fond of -fpermissive anyway: 
people should fix their codes rather than relying on things we don't promise 
will work indefinitely. Listing what -fpermissive does is like a promise that 
we will keep supporting their code. I'm not sure we want this.

> most importantly,
> reference the (enhanced) documentation on name lookup from there.

Feel free to add a link.

Thanks
  Wolfgang

-------------------------------------------------------------------------
Wolfgang Bangerth              email:            bangerth@ices.utexas.edu
                               www: http://www.ices.utexas.edu/~bangerth/