命令由于信号而失败:分段错误:在图类中使用泛型 - swift3 后为 11

Question

我试图在swift 3中创建一个通用的图结构。问题是编译器失败并显示以下消息：

While emitting IR SIL function ... for 'init' at .../Graph.swift:48:21

编译器指向的行是Edge类的 init 方法：

public class Edge<T: Hashable, V: Vertex<T>> {
    public var source: V
    public var destination: V
    public let weight: Double?
    required public init(source: V, destination: V, weight: Double? = nil) {
        self.source = source
        self.destination = destination
        self.weight = weight
    }
}

我想我可能是泛型使用的问题。以下是涉及的类：

public class Vertex<T: Hashable> {
    var data: T
    required public init(data: T) {
        self.data = data
    }
}
extension Vertex: Hashable {
    public var hashValue: Int {
        return "(data)".hashValue
    }
    static public func ==(lhs: Vertex, rhs: Vertex) -> Bool {
        return lhs.data == rhs.data
    }
}
extension Vertex: CustomStringConvertible {
    public var description: String {
        return "(data)"
    }
}
// MARK: - Edge
public enum EdgeType {
    case directed, undirected
}
public class Edge<T: Hashable, V: Vertex<T>> {
    public var source: V
    public var destination: V
    public let weight: Double?
    required public init(source: V, destination: V, weight: Double? = nil) {
        self.source = source
        self.destination = destination
        self.weight = weight
    }
}
extension Edge: Hashable {
    public var hashValue: Int {
        return "(source)(destination)(weight)".hashValue
    }
    // We need to overload the equals operator because Hashable implements Equatable
    static public func ==(lhs: Edge<T, V>, rhs: Edge<T, V>) -> Bool {
        return lhs.source == rhs.source && lhs.destination == rhs.destination && lhs.weight == rhs.weight
    }
}

这两个类由泛型AdjacencyList<T: Hashable, V: Vertex<T>, E: Edge<T, V>>

谢谢

Answer 1

无法告诉您代码崩溃的原因。您最好为此问题发送错误报告。但是我有一个解决方法：

public protocol VertexType: Hashable {
    associatedtype DataType
    var data: DataType { get set }
}
public class Vertex<T: Hashable>: VertexType {
    public var data: T
    required public init(data: T) {
        self.data = data
    }
}
extension Vertex {
    public var hashValue: Int {
        return "(data)".hashValue
    }
    static public func ==(lhs: Vertex, rhs: Vertex) -> Bool {
        return lhs.data == rhs.data
    }
}
extension Vertex: CustomStringConvertible {
    public var description: String {
        return "(data)"
    }
}
// MARK: - Edge
public class Edge<V: VertexType> {
    public var source: V
    public var destination: V
    public let weight: Double?
    required public init(source: V, destination: V, weight: Double? = nil) {
        self.source = source
        self.destination = destination
        self.weight = weight
    }
}
extension Edge: Hashable {
    public var hashValue: Int {
        return "(source)(destination)(weight)".hashValue
    }
    // We need to overload the equals operator because Hashable implements Equatable
    static public func ==(lhs: Edge<V>, rhs: Edge<V>) -> Bool {
        return lhs.source == rhs.source && lhs.destination == rhs.destination && lhs.weight == rhs.weight
    }
}

现在，您可以根据需要使用Vertex子类：

public class IntVertex: Vertex<Int> {}
Edge(source: IntVertex(data: 1), destination: IntVertex(data: 2))

更新：

看起来这在 Swift 3.1 中得到了修复。至少类似的错误不再使Xcode 8.3崩溃。因此，更新您的Xcode可能就足够了。