// FirestoreQuery.swift
@available(iOS 14.0, macOS 11.0, macCatalyst 14.0, tvOS 14.0, watchOS 7.0, *)
@propertyWrapper
public struct FirestoreQuery<T>: DynamicProperty {
  @StateObject private var firestoreQueryObservable: FirestoreQueryObservable<T>

// <--snip-->

  public var wrappedValue: T {
    firestoreQueryObservable.items // 💥 Main actor-isolated property 'firestoreQueryObservable' can not be referenced from a nonisolated context
  }

  /// A binding to the request's mutable configuration properties
  @MainActor @preconcurrency public var projectedValue: Configuration {
    get {
      firestoreQueryObservable.configuration // 💥 Main actor-isolated property 'firestoreQueryObservable' can not be referenced from a nonisolated context
    }
    nonmutating set {
      firestoreQueryObservable.objectWillChange.send() // 💥 Main actor-isolated property 'firestoreQueryObservable' can not be referenced from a nonisolated context
      firestoreQueryObservable.configuration = newValue // 💥 Main actor-isolated property 'firestoreQueryObservable' can not be referenced from a nonisolated context
    }
  }

// <--snip-->

}

@MainActor @frozen @propertyWrapper @preconcurrency public struct StateObject<ObjectType> : DynamicProperty where ObjectType : ObservableObject { ... }

class MyNonIsolatedClass {
  @FirestoreQuery(
    collectionPath: "fruits",
    predicates: [
      .where("isFavourite", isEqualTo: true),
    ]
  ) fileprivate var fruitResults: [Fruit]
  
  nonisolated func nonisolatedFunc() {
    // Xcode 15.2
    // Doesn't compile currently with or without `@MainActor @preconcurrency`
    // 💥 Main actor-isolated property 'fruitResults' can not be referenced from a nonisolated context
    
    // Xcode 16.1
    // Currently, without this PR's `@MainActor @preconcurrency`, this PR causes a warning:
    // ⚠️ Main actor-isolated property 'fruitResults' can not be referenced from a nonisolated context; this is an error in the Swift 6 language mode
    // Without @preconcurrency, this PR causes an error:
    // 💥 Main actor-isolated property 'fruitResults' can not be referenced from a nonisolated context
    // With @preconcurrency, this PR causes a warning:
    // ⚠️ Main actor-isolated property 'fruitResults' can not be referenced from a nonisolated context; this is an error in the Swift 6 language mode
    
    // Xcode 16.2 b2
    // Same behavior as 16.1

    print(fruitResults)
  }
  
  func defaultIsolationFunc() {
    // Xcode 15.2
    // No error/warn, with @preconcurrency or not
    
    // Xcode 16.1
    // Same as Xcode 15.2

    // Xcode 16.2 b2
    // Same as Xcode 16.1

    print(fruitResults)
  }
}