{"ast_node_type":"variable","tokens":[{"end":30,"kind":"keyword","start":0,"text":"let"}]}
            let param_ty_lhs =
            let br = ty::BoundRegion { var: ty::BoundVar::ZERO, kind: ty::BoundRegionKind::Anon };
                Ty::new_imm_ref(tcx, ty::Region::new_bound(tcx, ty::INNERMOST, br), param(0));