[Bug c/114808] Qualified void return type is not diagnosed

["luigighiron at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114808

--- Comment #5 from Halalaluyafail3 <luigighiron at gmail dot com> ---
I made this bug report because of the warning that clang has, but the following
paragraph may allow this:

> If, in the declaration "T D1", D1 has the form
> D ( parameter-type-list )
> or
> D ( identifier-list opt )
> and the type specified for ident in the declaration "T D" is
> "derived-declarator-type-list T", then the type specified for
> ident is "derived-declarator-type-list function returning the
> unqualified version of T".
Section 6.7.6.3 "Function declarators (including prototypes)" Paragraph 4
ISO/IEC 9899:2018

GCC seems to be using this to not make a diagnostic here, e.g. it warns with a
return type of _Atomic void in C17 mode but not in C23 mode where the text here
was updated to indicate that the result is the unqualified and non-atomic
version of T. If this would make the text talking about the return type of the
function refer to the unqualified return type then this should be allowed I
think, and I will make a bug report to clang to get this diagnostic changed.