* include/bits/stl_tree.h (_Rb_tree::erase(const Key*, const Key*)):
Remove unused, non-standard function.
As suggested in https://gcc.gnu.org/ml/libstdc++/2016-12/msg00100.html
I've removed this unused member.
Tested powerpc64le-linux, committed to trunk.
commit 4a182e12a82554
We have an unused overload of _Rb_tree::erase which takes a pair of
pointers (not iterators, pointers) to keys and calls erase for every
key in the range.
It's not actually doing any harm, as the function is only on the
internal _Rb_tree type. It's not exposed as a member of std::map,
std::set e
