所有类型都可以用作Swift中的错误？

enum VendingMachineError: Error {
  case invalidSelection
  case insufficientFunds(coinsNeeded: Int)
  case outOfStock
  }

throw VendingMachineError.insufficientFunds(coinsNeeded: 5)

extension Array: Error {}

do {
    throw [1, 2, 3]
} catch {
    print("Failed:", error) // Failed: [1, 2, 3]
}

这是更现实的例子,使用struct来抛出
附加信息的错误(简化示例来自
Swift 3 errors with additional data)：

struct ParserError: Error, LocalizedError {
    let line: Int

    public var errorDescription: String? {
        return "Parser error at line \(line)"
    }
}

func parse() throws {
    throw ParserError(line: 13)
}

do {
    try parse()
} catch let error {
    print(error.localizedDescription)
}

输出：

Parser error at line 13