https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111775
Bug ID: 111775
Summary: -Wstrict-flex-arrays missing diagnostics with unions
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: crrodriguez at opensuse dot org
Target Milestone: ---
following code is not diagnosed
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
struct foo {
int dum;
union {
/* or [1] */
char a[0];
wchar_t b[0];
} fn;
};
int main(void)
{
struct foo *f = malloc(sizeof(*f));
/* or really any use of the union does not matter */
printf("%p", f->fn.b);
free(f);
return 0;
}
compile options
-Wall -fstrict-flex-arrays -Werror=strict-flex-arrays -O2
This test is a silly mockup of real widespread code, which goes undiagnosed
until test suites run and/or is built with ubsan.
