{"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
        let is_vtable_shim = !fn_sig.inputs().skip_binder().is_empty()
        let fn_sig = tcx.fn_sig(def_id).instantiate_identity();
            && fn_sig.input(0).skip_binder().is_param(0)