{"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"impl<'a,"}]}
impl<'a, 'tcx> RegionRelations<'a, 'tcx> {
    pub(crate) fn new(tcx: TyCtxt<'tcx>, free_regions: &'a FreeRegionMap<'tcx>) -> Self {