{"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"(&ty::Ref(r_a,"}]}
        (&ty::Ref(r_a, ty_a, mutbl_a), &ty::Ref(r_b, ty_b, mutbl_b)) => {
    let (source, target, trait_def_id, kind, field_span) = match (source.kind(), target.kind()) {
            infcx.sub_regions(SubregionOrigin::RelateObjectBound(span), r_b, r_a);