具有协议类型的 Swiftui 选取器 - 编译器无法对此表达式进行类型检查

问：

鉴于这个符合协议的结构Relationable

struct RomanticRelation: Relationable{
    
    typealias Relationship = RomanticRelationType
    typealias Relation = RomanticRelation
    var nickname: String
    var lastInteracted: Date
    var relationship: RomanticRelationType = .couple //Enum type

}

protocol Relationable {
    
    associatedtype Relation
    associatedtype Relationship:Hashable  //Enum
    var nickname:String { get set }
    var lastInteracted:Date { get set }
    var relationship:Relationship { get set }
    var typicalInterests:[String] { get }
    var interests:[String] { get set }
    
}

而这个变量在符合PublishedObservableObject

class RelationsViewModel: ObservableObject {
    
    @Published var selectedRelation: any Relationable = PersonalRelation()

}

变量是符合 和relationshipEnumCaseIterableHashable

enum RomanticRelationType:Hashable, CaseIterable {
   

    case couple, married, engaged
    
    var title: String {
        
        switch self {
        case .couple:
            return "Couple"
        case .married:
            return "Married"
        case .engaged:
            return "Engaged"
        }
    }
    var priority: Int {
        switch self {
        case .couple:
            return 3
        case .engaged:
            return 2
        case .married:
            return 1
        }
    }
    
}

如果我有 3 个结构体符合协议，每个结构体都有这个变量（关系），我想将其分配给选择而不是制作 3 个PickerPicker

从协议中分配已知类型（String）时，其工作

 TextField("Nickname", text: $relationsVM.selectedRelation.nickname)
                                .modifier(TextFieldModifier(width: 250, height: 30))
                                .padding(.top)

但是，使用选择器，它将不起作用

Picker("Type", selection: $relationsVM.selectedRelation.relationship) {
    //ForEach got a simple string array
ForEach(relationsVM.allRelationships) { relationType in 
Text(relationType)
   }
  }.pickerStyle(.menu)

编译器无法进行类型检查和编译，我知道这是因为选择器的参数，也许需要在某处强制转换类型？selected