[PATCH] Objective-C++ : Allow prefix attrs on linkage specs.

Jason Merrill jason@redhat.com
Mon Nov 23 22:17:51 GMT 2020


On Mon, Nov 23, 2020 at 8:52 AM Iain Sandoe <iain@sandoe.co.uk> wrote:

> Jason Merrill <jason@redhat.com> wrote:
>
> > On 11/7/20 10:11 AM, Iain Sandoe wrote:
>
> >> +          warning_at (token1->location, OPT_Wattributes, "attributes
> are"
> >> +                      " only permitted in this position for
> Objective-C++,"
> >> +                      " ignored");
> >
> > It would be nice for the warning to suggest where to move the
> attribute,
> > rather than just say that this location is bad.
>
> f.C:
>
> __attribute__(())
> extern "C" int foo (void);
>
> ===
>
> So, I looked at two possibles.
>
> 1/ trying to use a fixit hint - but this seems a little lacking in
> information to me.
>
> f.C:2:1: warning: attributes are only permitted in this position for
> Objective-C++ (ignored for C++) [-Wattributes]
>      2 | __attribute__(())
>        | ^~~~~~~~~~~~~
>      3 | extern "C" int foo (void);
>        |            __attribute__
>
> (NOTE: ‘__attribute__' starting indent is below ‘int’ for a fixed spacing
> font)
>
> 2/ adding an inform:
>
> f.C:2:1: warning: attributes are only permitted in this position for
> Objective-C++ (ignored for C++) [-Wattributes]
>      2 | __attribute__(())
>        | ^~~~~~~~~~~~~
> f.C:3:12: note: for C++, attributes may be added here
>      3 | extern "C" int foo (void);
>        |            ^~~
>
> (NOTE: likewise,   ^~~ starting indent is below ‘int’ for a fixed spacing
> font)
>
> ===
>
> I’m inclined to think that the second is more useful,
> but have patches for both,
> which (or something else) do you prefer?
>

I agree that the second is preferable, thanks.  But let's not underline all
of "int" there, just the caret is sufficient.  I'd also drop the mention of
Obj-C++.

Jason


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