{"ast_node_type":"variable","tokens":[{"end":63,"kind":"keyword","start":0,"text":"let"}]}
        let fn_sig = tcx.fn_sig(def_id).instantiate_identity();
        debug!("resolve_for_vtable(def_id={:?}, args={:?})", def_id, args);
        let is_vtable_shim = !fn_sig.inputs().skip_binder().is_empty()