https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89722
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |msebor at gcc dot gnu.org
--- Comment #6 from Martin Sebor <msebor at gcc dot gnu.org> ---
I agree the macros obscure the problem. Here's a simpler test case:
$ cat t.C && gcc -S -Wall -Wextra -Wignored-qualifiers t.C
int f (void) {
typedef const int ConstInt;
return (ConstInt)1;
}
int g (const long *p) {
return (__typeof__ (*p))1;
}
#if __cplusplus
template <class T>
T h (T*) {
return (T)1;
}
int hh (const int *p)
{
return h (p);
}
#endif
t.C: In function ‘int f()’:
t.C:3:20: warning: type qualifiers ignored on cast result type
[-Wignored-qualifiers]
3 | return (ConstInt)1;
| ^
t.C: In function ‘int g(const long int*)’:
t.C:7:27: warning: type qualifiers ignored on cast result type
[-Wignored-qualifiers]
7 | return (__typeof__ (*p))1;
| ^
But the code above doesn't trigger either warning when compiled as C. I think
that suggests that either the manual should be updated to explain the
difference or the two front ends should be made to behave the same way. As a
data point, Clang doesn't warn in either C or C++ modes on this code so I
wonder if G++ is being overly pedantic here, especially in the typeof cases.
Btw., while G++ manages to avoid warning on template instantiation above, it
does warn the explicit instantiation below. That seems like a bug to me since
there's no way to avoid the warning if the template comes from some component
the user has no control over. (Clang has the same problem.)
gcc -O2 -S -Wall -Wextra -Wignored-qualifiers t.C
template <class T>
T h (T*) {
return (T)1;
}
int hh (const int *p)
{
return h (p);
}
template const long h<const long> (const long*);
t.C:11:10: warning: type qualifiers ignored on function return type
[-Wignored-qualifiers]
11 | template const long h<const long> (const long*);
| ^~~~~
