@Override
  protected @Nullable InspectionGadgetsFix buildFix(Object... infos) {
    final PsiJavaFile file = (PsiJavaFile)infos[0];
    final String fileName = file.getName();
    final int prefixIndex = fileName.indexOf('.');
    final String filenameWithoutPrefix = fileName.substring(0, prefixIndex);
    final PsiClass[] classes = file.getClasses();
    for (PsiClass psiClass : classes) {
      final String className = psiClass.getName();
      if (filenameWithoutPrefix.equals(className)) {
        return null;
      }
    }
    return new RenameFix(filenameWithoutPrefix);
  }
@Override
  protected @Nullable InspectionGadgetsFix buildFix(Object... infos)