Reactivecocoa: Can't bind Signal and mutableProperty to Disposable.

[ParkJonghyeok]

Recently, I updated to xcode9.
it occurred error message ‘Module compiled with Swift 3.1 cannot be imported in Swift 3.2

So I open a Terminal and type a command advice.

carthage update --platform iOS --no-use-binaries

It may resolve error, but Xcode constantly tell me about syntax error which is “generic parameter 'u' could not be inferred”

Here is my error code

func bindingData(viewModel: ItemTypeListViewModel) {
      self.disposable.dispose()
      let disposable = CompositeDisposable()
      self.disposable = disposable

      disposable += buttonModels <~ viewModel.types.take(during: reactive.lifetime).map {
           $0.enumerated().map {
                ItemTypeButtonModelImpl($1, isPressed: viewModel.selectType, index: $0)
           }
      }
 }       

Error line is here. In the line, Xcode showed me 'the red line' with syntax error message
generic parameter 'u' could not be inferred

disposable += buttonModel <~ /*<- this operator */ viewModel.type.take(...

It is my Cartfile.resolve's part of detail.

    github "ReactiveCocoa/ReactiveCocoa" "5.0.3"
    github "ReactiveCocoa/ReactiveSwift" "1.1.3"
    github "ReactiveX/RxSwift" "3.6.1"
    github "antitypical/Result" "3.2.3"

```swift
precedencegroup BindingPrecedence {
associativity: right
higherThan: AssignmentPrecedence
}

infix operator <~ : BindingPrecedence

/// Binds a source to a target, updating the target's value to the latest
/// value sent by the source.
///
/// - note: The binding will automatically terminate when the target is
/// deinitialized, or when the source sends a completed event.
///
/// /// let property = MutableProperty(0) /// let signal = Signal({ /* do some work after some time */ }) /// property <~ signal ///
///
/// /// let property = MutableProperty(0) /// let signal = Signal({ /* do some work after some time */ }) /// let disposable = property <~ signal /// ... /// // Terminates binding before property dealloc or signal's /// // `completed` event. /// disposable.dispose() ///
///
/// - parameters:
/// - target: A target to be bond to.
/// - source: A source to bind.
///
/// - returns: A disposable that can be used to terminate binding before the
/// deinitialization of the target or the source's completed
/// event.

public func <~(provider: Provider, source: Source) ->
Disposable? where Provider : BindingTargetProvider,
Source : BindingSource, Source.Error == Result.NoError,
Source.Value == Provider.Value

Here is link in stackoverflow.
[https://stackoverflow.com/questions/46389023/in-xcode9-with-reactiveswift-cant-bind-mutableproperty-and-signal-to-disposabl](https://stackoverflow.com/questions/46389023/in-xcode9-with-reactiveswift-cant-bind-mutableproperty-and-signal-to-disposabl)

This project was worked fine at Xcode 8.3.3. However I can’t build a project because of issues that I mentioned at Xcode9. Have you ever heard a problem like me? If you know about this problem, 
plz help me.
If you need more information, please give me a reply.
Thanks

**+add**

Another problem,
```swift
func bindingData(viewModel: ItemTypeListViewModel) {
      self.disposable.dispose()
      let disposable = CompositeDisposable()
      self.disposable = disposable

      let Signal = viewModel.types.take(during: reactive.lifetime).map {
           $0.enumerated().map {
                ItemTypeButtonModelImpl($1, isPressed: viewModel.selectType, index: $0)
           }
      }//ok       

      disposable += buttonModels <~ Signal 
    //Expression type 'Disposable?' is ambiguous without more context
}

In this case, shows "Expression type 'Disposable?' is ambiguous without more context" alert message with red line.
Am I mistaken for 'How to Use bind'?
If you know about this problem, plz help me.
Thanks!!

+add

protocol ItemTypeButtonModel {
    var type: ItemType { get }
    var isPressed: Action<Void, ItemTypeContext?, NoError> { get }
    var isSelected: MutableProperty<Bool> { get }
}

class ItemTypeButtonModelImpl: ItemTypeButtonModel {
    let type: ItemType
    let isSelected = MutableProperty<Bool>(false)
    let isPressed: Action<Void, ItemTypeSelectContext?, NoError>
    init(_ type: ItemType, isPressed: Action<ItemTypeContext, ItemTypeContext?, NSError>, index: Int) {
        self.type = type
        self.isPressed = Action { _ -> SignalProducer<ItemTypeContext?, NoError> in
            return isPressed.apply(ItemTypeContext(type: type, index: index)).flatMapError{ _ in .empty }
        }
    }
}

Here is ButtonModel and ViewModel.type !

ButtonModel is MutableProperty<[ItemTypeButtonModel]>
ViewModel.type is Signal<[ItemTypeButtonModelImpl], NoError>

[andersio]

What is the type of buttonModels and viewModel.types? It could be due to the types on both ends of <~ not matching with each other.

[ParkJonghyeok]

I added type information!
but, I think buttonModels and viewModel.types match.
ItemTypeButtonModelImpl has ItemTypeButtonModel's protocol

[andersio]

Could you try to add as ItemTypeButtonModel after instantiating ItemTypeButtonModelImpl?

[ParkJonghyeok]

Working well!
Thank you for your help! thank you!

[andersio]

It is kinda odd because coercing [C] to [P] given that C conforms to P works, just that it isn’t a generic environment like this binding. I guess this is a regression of Swift 3.2/4.0 if it did work in 3.1.

[ParkJonghyeok]

I absolutely agree with you.
I thought it was 'bug of Xcode9 with 3.2'...
Anyway, thanks again, Mr. andersio!
Have a nice day.