{"ast_node_type":"variable","tokens":[{"end":72,"kind":"keyword","start":0,"text":"let"}]}
    let polonius_diagnostics = polonius_context.map(|polonius_context| {
    // and use them to compute loan liveness.
        polonius_context.compute_loan_liveness(infcx.tcx, &mut regioncx, body, borrow_set)