https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81932
--- Comment #23 from Paul Smith <psmith at gnu dot org> --- The lookup_type() was just to show the problem more clearly: I don't do that in my actual Python code. This part (or something similar) is what I use: class tv(gdb.Function): def __init__(self): gdb.Function.__init__(self, "tv") def invoke(self, vector): gdb.write("depth: %d\n" % (vector['tree']['_depth'])) and when I run this I get: warning: RTTI symbol not found for class 'TreeVector<Pod, 2u>::Tree' In other words, it's not that I'm trying to look up that type myself: that's the type that GDB is trying to look up when it tries to evaluate the variable of type "TreeVector<Pod, 2>::Tree" in my program.