https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128412
Bug ID: 128412
Summary: [C23] Attribute specified on the declarator wrongly
applies to type and then wrongly reject (ignore
warning)
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
CC: jakub at gcc dot gnu.org, jsm28 at gcc dot gnu.org
Target Milestone: ---
This is a fallout of the OpenMP examples discussion
(internal examples issue #629) which has the following:
int a[100] [[ omp::decl(declare_target) ]],
b[100] [[ omp::decl(declare_target, link) ]];
A similar code without OpenMP is:
int a[100] [[deprecated]], b[100] [[deprecated]];
which GCC rejects with
warning: ‘deprecated’ attribute ignored
(And g++ rejects with:
warning: ‘deprecated’ on a type other than class or enumeration definition
and clang/clang++ rejects with
error: 'deprecated' attribute cannot be applied to types )
* * *
Side remark: All three compilers accept it when writing it as
'attribute-specifier-sequence declaration-specifiers init-declarator-list':
[[deprecated]] int a[100], b[100];
and print the proper warning when used.
* * *
Back to the original example:
int a[100] [[deprecated]], b[100] [[deprecated]];
this seems to fall into:
declaration-specifiers init-declarator-list(opt) ;
for init-declarator == declarator and then
direct-declarator:
identifier attribute-specifier-sequence(opt)
which is ISO/IEC 9899:2023 [here: N3096] under "6.7 Declarations" (page 96)
and then "6.7.6 Declarators" (page 124) – which then continues on page 125 with
the following in paragraph 5:
"If, in the declaration "T D1", D1 has the form
identifier attribute-specifier-sequenceopt
then the type specified for ident is T and the optional attribute specifier
sequence appertains to the entity that is declared."
Which seems to make this case valid. [Likewise for C++, but I still need to
dig the standard; Tom S. believes it works likewise in that case.]
