{"ast_node_type":"variable","tokens":[{"end":74,"kind":"keyword","start":0,"text":"let"}]}
                let nonzero_type = args.type_at(0); // Unwrap option type.
            ty::Adt(adt, args) if tcx.is_diagnostic_item(sym::Option, adt.did()) => {
                let ty::Adt(adt, args) = nonzero_type.kind() else {