[Bug libstdc++/63698] [5 Regression] std::set leaks nodes on assignment

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63698

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Does the same problem still exist in _M_extract?

This loop moves _M_nodes to the rightmost node again:

              while (_M_nodes->_M_right)
            _M_nodes = _M_nodes->_M_right;

Can that node have an _M_left child?