Does some restriction exist in SwiftUI for binding computed values?

I have a view, and in this view I bind Axis class values — lowerBound which is a regular property and at – computed one which comes from protocol HasPositionProtocol associated with Axis.

struct AxisPropertiesView<Axis>: View 
where Axis: StyledAxisProtocol, 
      Axis: HasPositionProtocol,
      Axis: Observable
{
      @Bindable var axis: Axis
       
     var body: some View {
        HStack {
            TextField("", text: $axis.shortName)
                .frame(width: 40)       
            TextField("",
                      value: $axis.lowerBound, 
                      format: .number)
            .frame(width: 45)
            //Problem is here:
            Slider(value: $axis.at,
                   in: axis.bounds) 
            ...

Unfortunately I got en error Failed to produce diagnostic for expression; ... for whole View. But if I remove Slider from View, error disappeared. What could cause this strange behaviour?

Value of .at comes from:

public extension HasPositionProtocol {
    ///Absolut position on Axis
    var at: Double {
        get {
            switch position {
            case .max:
                return bounds.upperBound
            case .min:
                return bounds.lowerBound
            case .number(let number):
                return number
            }
        }
        set {
            switch newValue {
            case bounds.lowerBound:
                position = .min
            case bounds.upperBound:
                position = .max
            default:
                position = .number(newValue)
            }
        }
    }
}