[Bug middle-end/97374] New: missing essential detail in array parameter overflow warning

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97374

            Bug ID: 97374
           Summary: missing essential detail in array parameter overflow
                    warning
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

The warning below doesn't provide enough information to understand what the
problem is.  The first note should say something like

  note: referencing argument 1 of type ‘int[4]’

$ cat q.c && gcc -O2 -S -Wall q.c
typedef int A[3];
typedef int B[4];

void f (B);

struct S { A x; B y; };

void g (struct S *p)
{
  f (p->x);
}
q.c: In function ‘g’:
q.c:10:3: warning: ‘f’ accessing 16 bytes in a region of size 12
[-Wstringop-overflow=]
   10 |   f (p->x);
      |   ^~~~~~~~
q.c:10:3: note: referencing argument 1 of type ‘int *’
q.c:4:6: note: in a call to function ‘f’
    4 | void f (B);
      |      ^