         case let raw as NSArray:
             var array = [JsonValue]()
             for item in raw {
-                array += JsonValue(item)
+                array.append(JsonValue(item))
             }
             self = .JsonArray(array)
 

    case JsonNull
    case JsonInvalid(NSError)

    init(_ rawValue: AnyObject) {
        switch rawValue {
        case let raw as NSNull:
            self = .JsonNull

    public var int: Int? {
        switch self {
        case .JsonNumber(let value): return value.integerValue
        case .JsonString(let value): return ((value as NSString).integerValue)
        case .JsonBool(let value): return Int(value)
        default: return nil
        }
