__parent_ not found in rbtree node?

[abrownsword]

I've noticed that I'm getting these errors in the gdb console:

Traceback (most recent call last):
File "/home/andrew/.gdb/libcxx-pretty-printers/src/libcxx/v1/printers.py", line 615, in next
item = self.rbiter.next()
File "/home/andrew/.gdb/libcxx-pretty-printers/src/libcxx/v1/printers.py", line 673, in next
parent_node = parent_node.dereference()['_parent']
gdb.error: There is no member or method named _parent.

(note my line numbers will differ from the head of tree)