As reported in https://bugzilla.redhat.com/show_bug.cgi?id=1907216, GCC 11 issues a spurious -Warray-bounds on the following code (reduced from the original test case):

$ cat rhbz1738791.C && g++ -O2 -S -Wall rhbz1738791.C
struct A
{
  virtual ~A() noexcept;
  const char* s;
};

struct B: virtual A { };

struct C: virtual B { };

struct D: virtual A { };

struct E: virtual B, virtual D
{
  E (const char*);
};

void f (E);

void g_function ()
{
  f (E (""));
}
rhbz1738791.C: In function ‘void g_function()’:
rhbz1738791.C:11:8: warning: array subscript ‘D[1]’ is partly outside array bounds of ‘E [1]’ [-Warray-bounds]
   11 | struct D: virtual A { };
      |        ^
rhbz1738791.C:22:11: note: while referencing ‘<anonymous>’
   22 |   f (E (""));
      |           ^
rhbz1738791.C:11:8: warning: array subscript ‘D[1]’ is partly outside array bounds of ‘E [1]’ [-Warray-bounds]
   11 | struct D: virtual A { };
      |        ^
rhbz1738791.C:22:11: note: while referencing ‘<anonymous>’
   22 |   f (E (""));
      |           ^