DocumentSourceMatch::splitSourceBy(const std::set<std::string>& fields,
                                   const StringMap<std::string>& renames) && {
    return std::move(*this).splitSourceByFunc(fields, renames, expression::isIndependentOf);
}
DocumentSourceMatch::splitSourceBy(const std::set<std::string>& fields,
                                   const StringMap<std::string>& renames) && {
    return std::move(*this).splitSourceByFunc(fields, renames, expression::isIndependentOf);
}