@Override
  protected Object clone() {
    PsiImportListImpl clone = (PsiImportListImpl)super.clone();
    clone.myClassNameToImportMap = null;
    clone.myPackageNameToImportMap = null;
    clone.myNameToSingleImportMap = null;
    clone.myModuleNameToImportMap = null;
    return clone;
  }
@Override
  protected Object clone()