https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118035
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |5.4.0
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |redi at gcc dot gnu.org
Known to fail| |5.5.0
Summary|deque<string> bug when |[12/13/14/15 Regression]
|inserting an empty iterator |deque<string> bug when
|interval |inserting an empty iterator
| |interval
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This operation was always technically undefined on GCC's std::deque, because
std::copy_backward has a precondition that the result is not in the input
range. It happened to work because the std::string copy assignment operator
(like most copy assignment operators) is safe for self-assignment.
It continued to "work" after r0-84386-g7ffec97f9e0019 replaced
std::copy_backward with std::move_backward (despite that having the same
precondition).
It only started to lose data with my r5-9770-g397c5bf9204cc8 which
re-implemented the std::string move assignment, where the new implementation
left a string empty after self-move-assignment.
