Our hack to generate a unique name by appending the class pointer doesn't produce a stable class name that can persist in NSKeyedArchiver, or eventually be used as a key for dynamic runtime instantiation. Generate a proper mangled name for the class instance by building a demangling AST from the metadata nodes and feeding it into the remangler. Should fix rdar://problem/18884563, though I need to try using an archiver with a generic class to verify.
Swift SVN r29316
