> > I don't have tests for that but since it's not new behavior I suppose
> > that's sufficient.
>
> Each attribute should have tests that invalid uses are appropriately
> diagnosed. See gcc.dg/c23-attr-fallthrough-2.c for examples of such tests
> in the case of the [[fallthrough]] attribute. Some invalid uses may be
> diagnosed by existing code that's generic across attributes, others
> require specific code for the individual attribute.
Okay I can add a test for the other statement and declaration cases like
below.
Any other change you need for approval?
>
> The default parsing of an attribute without an entry in the table of
> attribute handlers is that arbitrary balanced token sequences are parsed
> and discarded as arguments.
And it triggers a warning too (see below)
> To diagnose such arguments (in contexts when
> the attribute is otherwise valid), an entry in the table of attribute
> handlers is appropriate.
The only valid usage is [[musttail]] return and there is already the default
warning in the other cases. So I don't think an entry in the table is needed.
BTW I noticed that [[musttail]] ; (empty statement with attribute) gives an
error, which
is probably a (unrelated) bug, afaik that should be legal for C23.
-Andi
t.c:
[[musttail]] int j;
__attribute__((musttail)) int k;
void foo(void)
{
[[musttail]] j++;
[[musttail]] if (k > 0)
[[musttail]] k++;
}
t.c:2:1: warning: ‘musttail’ attribute ignored [-Wattributes]
2 | [[musttail]] int j;
| ^
t.c:3:1: warning: ‘musttail’ attribute directive ignored [-Wattributes]
3 | __attribute__((musttail)) int k;
| ^~~~~~~~~~~~~
t.c: In function ‘foo’:
t.c:7:9: warning: ‘musttail’ attribute ignored [-Wattributes]
7 | [[musttail]] j++;
| ^
t.c:8:9: warning: ‘musttail’ attribute ignored [-Wattributes]
8 | [[musttail]] if (k > 0)
| ^
t.c:9:17: warning: ‘musttail’ attribute ignored [-Wattributes]
9 | [[musttail]] k++;
