https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114163
Harald van Dijk <harald at gigawatt dot nl> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |harald at gigawatt dot nl --- Comment #1 from Harald van Dijk <harald at gigawatt dot nl> --- You may be right that the class is not complete at that point but there is no requirement for the class to be complete. CWG1836 changed that to "In both cases, the class type shall be complete unless the class member access appears in the definition of that class." Here, the class member access does appear in the definition of the class, so it's okay that the class is incomplete.