Can't build a project when using ReducerOf

[jaroshevskii]

Description

Code from the Readme

Checklist

• I have determined whether this bug is also reproducible in a vanilla SwiftUI project.
• If possible, I've reproduced the issue using the main branch of this package.
• This issue hasn't been addressed in an existing GitHub issue or discussion.

Expected behavior

Must be compiled

Actual behavior

No response

Reproducing project

FuckingTCA.zip

The Composable Architecture version information

1.20.2

Destination operating system

iOS 26

Xcode version information

26.0 beta

Swift Compiler version information

swift-driver version: 1.115.1 Apple Swift version 6.0.3 (swiftlang-6.0.3.1.10 clang-1600.0.30.1)
Target: x86_64-apple-macosx15.0

[jaroshevskii]

The problem is in @mainactor isolation which is enabled by default from 26 xcode

[mbrandonw]

Hi @jaroshevskii, yes, the default isolation stuff isn't fully baked yet so we aren't yet sure what kinds of changes we will need to make to the library. We are keeping tabs on things are evolving and have some experiments to play nicely with default isolation, but since Swift 6.2 / Xcode 26 are still in beta there isn't much we can do right now.

Since this isn't an issue with the library I am going to convert it to a discussion. Please feel free to continue the conversation over there!