[Macro] Circular reference error when adding extensions to a type decorated by a peer macro

li3zhen1 · 2023-10-25T18:58:56.990Z

Hi!
I've been working on macros recently. Here's a macro that replaces a generic parameter and puts a new specialized version alongside the original type.

Screenshot 2023-10-25 at 15.32.172166×1332 435 KB

The code without extension part compiles, but it produces circular reference error when adding the extension. And if I move the extension to another file, code compiles.

I did some search and only found this: https://github.com/apple/swift-evolution/blob/main/proposals/0389-attached-macros.md#restrictions-on-arbitrary-names , but not sure if they are actually the same situation.

Is it by design or some bug?

li3zhen1 · 2023-10-25T19:03:11.942Z

Source code of the macro: GitHub - li3zhen1/WithSpecializedGeneric: An experimental peer macro expanding generic struct or class to a specialized type, so as to avoid dynamic dispatch

stephencelis · 2023-10-25T22:02:00.531Z

This might be related to this bug, which has had quite a bit of discussion, though none from the team yet, and it hasn't been triaged.

github.com/apple/swift

Extensions for subtype of a class marked @Observable generate compile error

opened 02:53PM - 08 Jun 23 UTC

virasio

bug triage needed

**Description** I cannot add a subtype (class, enum, struct) to a class marked …with `@Observable` macro. If I add an extension to this subtype, I get compile error: > Circular reference resolving attached macro 'Observable' **Steps to reproduce** ```swift @Observable class MyObservableClass { var property1 = "" var property2 = MyClass() } extension MyObservableClass { class MyClass { var property = "" } } extension MyObservableClass.MyClass { var test: String { "test \(property)" } } ``` **Expected behavior** It must be compilable because the following version is compilible: ```swift @Observable class MyObservableClass { var property1 = "" var property2 = MyClass() } extension MyObservableClass { class MyClass { var property = "" var test: String { "test \(property)" } } } ``` **Environment** Xcode 15.0 beta (15A5160n) Swift 5.9 Target: iOS 17.0

j_sung_0o0 · 2024-02-15T09:17:48.440Z

fyi, has been fixed: [Availability] Lazily expand type refinement contexts for extensions. by hborla · Pull Request #71365 · apple/swift · GitHub (not released yet)

dnadoba · 2024-02-15T14:37:31.214Z

This is a bug. Can you please fill an issue here and post it again to this thread.
Preferable with a simple reproducer if you can. Thank you!

hborla · 2024-02-15T15:07:59.348Z

This should be fixed by [Availability] Lazily expand type refinement contexts for extensions. by hborla · Pull Request #71365 · apple/swift · GitHub

dnadoba · 2024-02-15T16:12:03.143Z

Ah amazing, thank you! Recently run into this as well and could reproduce it on main but this PR was just merged last week.