#if BEFORE public struct ResilientStruct { public init() {} public var value: Int = 0 public mutating func change(_ keyPath: WritableKeyPath = \.value) -> Int { self[keyPath: keyPath] = 10 return value } } #else public struct ResilientStruct { public init() {} private var _value: Int = 0 public var value: Int { get { return -_value } set { _value = -newValue } } public mutating func change(_ keyPath: WritableKeyPath = \.value) -> Int { self[keyPath: keyPath] = 10 return value } } #endif