demangle is currently designed to demangle functions names, while the strings above are types. During parsing, demangle sees the string as a qualified name and then expects a type, and when it doesn't find one it figures the symbol isn't valid. It sounds like we either need a separate function for demangling types or if the demangle function encounters a 'Z' when it expects a type name it should realize it's demangling a type name, back up, and try again according to that logic. I suggest submitting a ticket.
I submitted a ticket along these lines.
