protected PsiFileImpl cloneImpl(FileElement treeElementClone) {
    PsiFileImpl clone = (PsiFileImpl)super.clone();
    clone.setTreeElementPointer(treeElementClone); // should not use setTreeElement here because the cloned file still has VirtualFile (SCR17963)
    treeElementClone.setPsi(clone);
    return clone;
  }
protected PsiFileImpl cloneImpl(FileElement treeElementClone)