{"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
                let span = tcx.hir_span_if_local(def_id).unwrap_or(DUMMY_SP);
                let def_id = tcx.generics_of(self.mir_def_id()).region_param(ebr, tcx).def_id;
                RegionName { name: ebr.name, source: RegionNameSource::NamedEarlyParamRegion(span) }