We currently don't support annotations on implicit extends for class declarations see comment on: [VariableAnnotator#createImpliedExtendsLocation(com.sun.source.tree.ClassTree)](https://github.com/typetools/checker-framework-inference/blob/244acdab3d89425caf3c460a9bc76ccba7735ea8/src/checkers/inference/VariableAnnotator.java#L804-L812) And according to the email exchange below, we should not.