https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120978
Bug ID: 120978
Summary: Punctuators that contain # or %: are incorrectly
rejected within attributes
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: luigighiron at gmail dot com
Target Milestone: ---
The following code is not accepted by GCC:
[[ignored(##)]]int main(){}
Unknown attributes should be ignored, so this code should be valid. The issue
seems to be that GCC rejects any code that contains #, ##, %:, and %:%:
punctuators after preprocessing. However, these punctuators can be validly used
within attributes so they shouldn't be rejected unconditionally. Clang accepts
this code, ignoring the warning for an ignored attribute.
This bug also exists in the GCC C++ compiler.
