public @Nullable PsiElement performFix(@Nullable PsiElement node) {
    if (node == null) return null;
    PsiElement element = node instanceof PsiFile ? node.getFirstChild() : node;
    Ref<PsiElement> newElementRef = Ref.create(null);
    WriteAction.run(() -> { performFixInner(element, newElementRef); });
    return newElementRef.get();
  }
public @Nullable PsiElement performFix(@Nullable PsiElement node)