自動生成されたDecodableのイニシャライザをサブクラスでオーバーライドできる様になってた。 @swift-4.1.3 @swift-4.2.4

import Foundation private class Person: Codable { let name: String init(name: String) { self.name = name } } private class Employee: Person { let id: Int init(name: String, id: Int) { self.id = id super.init(name: name) } enum CodingKeys: String, CodingKey { case id } required init(from decoder: Decoder) throws { let container = try decoder.container(keyedBy: CodingKeys.self) id = try container.decode(Int.self, forKey: .id) try super.init(from: decoder) } override func encode(to encoder: Encoder) throws { var container = encoder.container(keyedBy: CodingKeys.self) try container.encode(id, forKey: .id) try super.encode(to: encoder) } }

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