On 8/15/24 5:13 PM, Jakub Jelinek wrote:
Hi!
For C++ 26 P2552R3 I went through all the spots (except modules) where
attribute-specifier-seq appears in the grammar and tried to construct
a testcase in all those spots, for now for [[deprecated]] attribute.
The patch below contains that testcase. One needed change for this
particular attribute was that currently we handle [[deprecated]]
exactly the same as [[gnu::deprecated]], but for the latter unlike C++14
or later we allow it also on almost all types, while the standard
is strict and allows it only on
https://eel.is/c++draft/dcl.attr#deprecated-2
The attribute may be applied to the declaration of a class, a typedef-name,
a variable, a non-static data member, a function, a namespace,
an enumeration, an enumerator, a concept, or a template specialization.
The following patch just adds a pedwarn for the cases that gnu::deprecated
allows but C++14 disallows, so integral/floating/boolean types,
pointers/references, array types, function types etc.
Basically, for TYPE_P, if the attribute is applied in place (which means
the struct/union/class/enum definition), it is allowed, otherwise pedwarned.
The testcase still contains some FIXMEs I'd like to discuss.
I've tried to compile it also with latest clang and there is agreement in
most of the diagnostics, just at block scope (inside of foo) it doesn't
diagnose
auto e = new int [n] [[deprecated]];
auto e2 = new int [n] [[deprecated]] [42];
[[deprecated]] lab:;
and at namespace scope
[[deprecated]];
I think that all feels like clang++ bug.
On the other side, clang++ diagnoses
enum B { B0 } [[deprecated]];
but GCC with all the patches I've posted today doesn't, is that a GCC bug?
I think so, yes.
We diagnose struct A { } [[deprecated]]; ...
That seems correct.
The FIXMEs are where there is agreement with clang++, but I'm not sure.
One thing is I'm not sure if "a variable" above is meant to include function
parameters, and/or unused function parameters without a specified name,
function parameters inside of a function declaration rather than definition
and/or static data members.
All of those, I believe.
Also unsure about
[[deprecated]] int : 0;
at class scope, that isn't a non-static data member...
Indeed, pedantically the standard says it can't apply to an unnamed
bit-field.
Jason
