{"ast_node_type":"variable","tokens":[{"end":53,"kind":"keyword","start":0,"text":"let"}]}
    let span = tcx.def_span(item_def_id.to_def_id());
    let ty = tcx.type_of(item_def_id).instantiate_identity();
    if !ensure_wf(tcx, typing_env, ty, item_def_id, span) {