[Bug libstdc++/112491] std::deque::size xmethod output is wrong

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112491

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to ks1322 from comment #0)
>     d.push_front(0);

The bug occurs when the first node of the deque is not filled from the first
element. That case was never tested.