{"ast_node_type":"variable","tokens":[{"end":15,"kind":"keyword","start":0,"text":"let"}]}
    let cause =
    let body_def_id = cx.tcx.hir_body_owner_def_id(body_id);
        ObligationCause::new(span, body_def_id, rustc_infer::traits::ObligationCauseCode::Misc);