void (@NotNull PsiClass aClass) { // no call to super, so that it doesn't drill down to inner classes if (!aClass.isInterface() || aClass.isAnnotationType()) { return; } final PsiClass[] innerClasses = aClass.getInnerClasses(); for (final PsiClass innerClass : innerClasses) { if (isInnerClass(innerClass)) { registerClassError(innerClass, aClass); } } }