[Bug libstdc++/86295] Missing exception safety when inserting range into vector

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86295

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
P.S. the uninitialized_xxx algos have to work that way, because if an exception
occurs the caller has no way to know how many objects got created before the
exception, so the functions could never be used reliably if they didn't do
their own cleanup.