During refactoring of an app I made a typo which leads to a misleading error message in Xcode. I could reproduce it with a small sample code. Is it a bug which I should report?
Details:
I have an array containing two strings.Using a ForEach loop is fine:
ForEach(appData.dataArray, id: \.self) { value in
Text("\(value.subject)\t\(value.room)")
}
but with a typo in the Text line I got an error on the ForEach line:
ForEach(appData.dataArray, id: \.self) { value in
--> Cannot convert value of type '[MyArray]' to expected argument type 'Binding'
Text("\(value.subject)\t\(value.subject.room)")
}
Complete sample code from Swift Playground (macOS 26):
import SwiftUI
class MyArray : Hashable, Equatable, Identifiable, ObservableObject, Codable {
let id = UUID()
@Published var subject: String
@Published var room : String
private enum CodingKeys : String, CodingKey {
case subject
case room
}
init(subject : String, room : String) {
self.subject = subject
self.room = room
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(subject, forKey: .subject)
try container.encode(room, forKey: .room)
}
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
subject = try container.decode(String.self, forKey: .subject)
room = try container.decode(String.self, forKey: .room)
}
static func == (v1: MyArray, v2: MyArray) -> Bool {
let result = v1.id == v2.id
return result
}
func hash(into hasher: inout Hasher) {
hasher.combine(id)
}
}
public class AppData : ObservableObject {
@Published var dataArray : [MyArray] = []
init() {
dataArray.append(MyArray(subject: "Foo", room: "Bar"))
dataArray.append(MyArray(subject: "Foo", room: "Batz"))
}
}
struct ContentView: View {
@EnvironmentObject var appData : AppData
var body: some View {
ForEach(appData.dataArray, id: \.self) { value in
Text("\(value.subject)\t\(value.subject.room)") // to fix the error replace value.subject.room with value.room
}
}
}
@main
struct MyApp: App {
var appData = AppData()
var body: some Scene {
WindowGroup {
ContentView()
.environmentObject(appData)
}
}
}