void (PsiClass aClass) { final PsiReferenceList extendsList = aClass.getExtendsList(); if (extendsList == null) { return; } final PsiJavaCodeReferenceElement[] extendsElements = extendsList.getReferenceElements(); for (PsiJavaCodeReferenceElement extendsElement : extendsElements) { checkExtendedInterface(extendsElement, extendsElements); } }