AlamofireObjectMapper.swift line 74 works in Playground but not on device or emulator

How can the following be working in Xcode Playground and not when running on device or emulator.

Alamofire is returning allright with everything. I can pass it with .responseJSON no problem.

But using .responseObject it fails here in line 74 with SIGABRT

And the console says: Message from debugger: Terminated due to signal 9

Again, this is working from Playground with same classes and Alamofire.request

    Alamofire.request(
        url_planday_employees,
        method: .get,
        headers: headers_employees).responseObject { (response: DataResponse<Items>) in
            // Error
            for item in (userResponse?.items)! {
                if let user = item.user {
                    print("Result in... user")
                    print("Name:" + user.name! )
                }
            }
    }

The Classes:

class User: Mappable {
    var name: String?
    var id: Int?

    required init?(map: Map){}

    func mapping(map: Map) {
        name <- map["name"]
        id <- map["id"]
    }
}

class Item: Mappable {
    var user: User?

    required init?(map: Map){}

    func mapping(map: Map) {
        user <- map["item"]
    }
}

class Items: Mappable {
    var items: [Item]?

    required init?(map: Map){}

    func mapping(map: Map) {
        items <- map["items"]
    }
}

The JSON:

{
    "items": [
              {
              "item": {
              "id": 1,
              "name": "Anders And"
              }
              },
              {
              "item": {
              "id": 2,
              "name": "Andersine"
              }
              }
              ]
}

Solution

It looks like the problem was about incompatibility issues between 2.2.1 and 2.2.2 of ObjectMapper library.

Here is the related issues opened a while ago:

For a quick fix, you can use the older version (2.2.1):

As for carthage here is how it is done:

github "Alamofire/Alamofire" ~> 4.3.0
github "tristanhimmelman/AlamofireObjectMapper" ~> 4.0.1
github "Hearst-DD/ObjectMapper" == 2.2.1

Update

As of version 2.2.3, problem seems to be fixed:

github "Hearst-DD/ObjectMapper" ~> 2.2.3