<deque>: erase with two iterators invokes move / move_backward when the range is empty

[Bekenn]

STL/stl/inc/deque

Line 1295 in 4e97255

if (_Off < static_cast<size_type>(end() - _Last)) { // closer to front

This runs counter to the preconditions on std::move, which requires that the destination iterator is outside the source range.

[CaseyCarter]

Ugh. We self-move-assign every element in the shorter of [begin(), x) or [x, end()) when someone calls erase(x, x). Thanks for the report!

[Bekenn]

Yup. Looks like vector used to have the same issue, but was fixed some time back.