{"ast_node_type":"other","tokens":[{"end":66,"kind":"keyword","start":0,"text":")"}]}
) -> (Frozen<IndexVec<RegionVid, RegionDefinition<'tcx>>>, bool) {
    infcx: &BorrowckInferCtxt<'tcx>,
    let var_infos = infcx.get_region_var_infos();