Eu tenho o UITableViewController abaixo anexado como um searchResultsController:

import UIKit
import MapKit

class LocationSearchTable : UITableViewController {
    var matchingItems:[MKMapItem] = []
    var mapView: MKMapView? = nil

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.dataSource = self
        tableView.delegate = self
    }
}

extension LocationSearchTable : UISearchResultsUpdating {
    func updateSearchResults(for searchController: UISearchController){
        guard let mapView = mapView,
            let searchBarText = searchController.searchBar.text else { return }
        let request = MKLocalSearchRequest()
        request.naturalLanguageQuery = searchBarText
        request.region = mapView.region
        let search = MKLocalSearch(request: request)
        search.start { response, _ in
            guard let response = response else {
                return
            }
            self.matchingItems = response.mapItems
            self.tableView.reloadData()
        }
    }

}

extension LocationSearchTable {
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        print(matchingItems.count)
        return matchingItems.count
    }

     func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell")!
        let selectedItem = matchingItems[indexPath.row].placemark
        cell.textLabel?.text = selectedItem.name
        cell.detailTextLabel?.text = ""
        return cell
    }
}

Aqui ele caiu uma vezmatchingItems.count não é igual a 0, por exemplo:

0 0 10-20-10 de 2016 15: 43: 53.914 ios-App [9137: 977735]* Falha de asserção em - [UITableView _configureCellForDisplay: forIndexPath:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3599.6/UITableView.m:8035 20/10/2016 15: 43: 53.927 ios Aplicativo [9137: 977735] * Finalizando o aplicativo devido à exceção não capturada 'NSInternalInconsistencyException', motivo: 'UITableView (; layer =; contentOffset: {0, -64}; contentSize: {768, 440}>) falhou ao obter uma célula de seus dados

Quando adiciono pontos de depuração no cellForRowAtIndexPath, eles nunca são alcançados, o aplicativo parece falhar antes desse ponto?