{"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
    let infcx = &tcx.infer_ctxt().build(TypingMode::non_body_analysis());
    let param_env = tcx.param_env(body_def_id);
    let ocx = ObligationCtxt::new_with_diagnostics(infcx);