{"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
    let preds = tcx.mk_poly_existential_predicates_from_iter(
    assoc_preds.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
        iter::once(principal_pred).chain(assoc_preds.into_iter()),