https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119476
Bug ID: 119476
Summary: [-Wdiscarded-qualifiers] False negative with
-fplan9-extensions inheritance
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: alx at kernel dot org
Target Milestone: ---
alx@devuan:~/tmp$ cat q.c | grep -Tn ^
1: struct foo {
2: int a;
3: };
4:
5: struct bar {
6: struct foo;
7: };
8:
9: void f(struct foo *);
10: void g(char *);
11:
12: int
13: main(void)
14: {
15: const struct bar b;
16:
17: f(&b);
18:
19: const char *s = "foo";
20:
21: g(s);
22: }
alx@devuan:~/tmp$ gcc -Wall -Wextra -fplan9-extensions -S q.c
q.c: In function ‘main’:
q.c:21:11: warning: passing argument 1 of ‘g’ discards ‘const’ qualifier from
pointer target type [-Wdiscarded-qualifiers]
21 | g(s);
| ^
q.c:10:8: note: expected ‘char *’ but argument is of type ‘const char *’
10 | void g(char *);
| ^~~~~~
Line 17 should trigger a similar diagnostic. It seems inheritance is not
inheriting the qualifiers from the declared type of the object, which was
'const struct bar', and whose const is propagated to all members.
