{"ast_node_type":"other","tokens":[{"end":72,"kind":"keyword","start":0,"text":"check_mutbl(mt_a,"}]}
            check_mutbl(mt_a, mt_b, &|ty| Ty::new_imm_ref(tcx, r_b, ty))
            let mt_b = ty::TypeAndMut { ty: ty_b, mutbl: mutbl_b };
        }