Re: [PATCH 1/3] Support lambda templates.

[Adam Butcher <adam at jessamine dot co dot uk>]

On 12.08.2013 16:47, Jason Merrill wrote:
> On 08/11/2013 03:49 PM, Adam Butcher wrote:
> > +      if (cxx_dialect < cxx1y || flag_iso)
> > +	cp_parser_error (parser,
> > +			 "lambda templates are only available with "
> > +			 "-std=gnu++1y");
>
> Normally we only use flag_iso to disable extensions that can change
> the meaning of conforming code, which I don't think is the case here.
> For pure extensions, we prefer to use a pedwarn.

Okay.  Though I'm not sure how to implement exactly what we discussed
before with pedwarn.  Namely:

On 07.08.2013 16:59, Jason Merrill wrote:
> On 08/07/2013 03:52 AM, Adam Butcher wrote:
> > I'm not sure which dialect guards to put these features behind 
> > though.
> > Strictly:
> >
> >   a) Generic lambdas created fully implicitly via 'auto params' 
> > should be
> >      accepted with -std=c++1y and -std=gnu++1y since it is actually 
> > spec'd by
> >      the draft.
> >
> >   b) Generic lambdas created with an explicit template parameter 
> > list should be
> >      accepted with -std=gnu++1y only.
> >
> >   c) Generalized implicit function templates should be accepted by 
> > -std=gnu++1y
> >      only.
>
> This makes sense to me.  Or perhaps add (c) to the concepts lite
> flag, when there is one.

Presumably with pedwarn it would need to be relaxed to simply
   "accepted with -std=c++1y or -std=gnu++1y"
for all?  flag_iso was the only thing I could find to discriminate 
between gnu++1y
and c++1y?

> > +	  if (!DECL_TEMPLATE_INFO (decl) || DECL_TEMPLATE_RESULT
> > +	      (DECL_TI_TEMPLATE (decl)) != decl)
>
> This needs reformatting so that the arguments to a macro aren't to
> the left of the macro name.
Done.

Adam