{"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
    let ty = tcx.type_of(item_def_id).instantiate_identity();
    let typing_env = ty::TypingEnv::post_analysis(tcx, item_def_id);
    let span = tcx.def_span(item_def_id.to_def_id());