如何在Swift 3中查找Foundation方法抛出的异常？

Question

有没有办法找到Swift 3中的Foundation方法抛出的异常？特别是，我正在使用FileManager类将文件从应用程序包复制到文档目录。如果目标文件存在，copyItem方法将引发异常。如何捕获特定的异常？我发现的唯一方法是解析localizedDescription，这是丑陋的，可能不健壮：

func copySampleReport() {
    let fileManager = FileManager()
    let reportName = "MyFile.txt"
    if let documentUrl = try? fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false), let reportUrl = Bundle.main.url(forResource: URL(fileURLWithPath: reportName).deletingPathExtension().lastPathComponent, withExtension: URL(fileURLWithPath: reportName).pathExtension) {
        debugPrint("Copying \(reportUrl) to \(documentUrl)")
        do {
            try fileManager.copyItem(at: reportUrl, to: documentUrl.appendingPathComponent(reportName))
            debugPrint("File copied succesfully!")
        }
        catch {
            if error.localizedDescription.range(of:"exists") != nil {
                debugPrint("File exists at destination")
            } else {
                debugPrint(error.localizedDescription)
            }
        }
    }
}