# \[Accepted\] SE-0471: Improved Custom SerialExecutor isolation checking for Concurrency Runtime

**URL:** <https://forums.swift.org/t/accepted-se-0471-improved-custom-serialexecutor-isolation-checking-for-concurrency-runtime/79894>\
**Category:** Announcements\
**Created:** [May 14, 2025, 5:14pm UTC](https://forums.swift.org/t/accepted-se-0471-improved-custom-serialexecutor-isolation-checking-for-concurrency-runtime/79894 "2025-05-14T17:14:46Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Douglas\_Gregor](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/douglas_gregor/32/1362_2.png) [@Douglas\_Gregor](https://forums.swift.org/u/Douglas_Gregor)\
**Post date:** [May 14, 2025, 5:14pm UTC](https://forums.swift.org/t/accepted-se-0471-improved-custom-serialexecutor-isolation-checking-for-concurrency-runtime/79894/1 "2025-05-14T17:14:46Z")

</div>

Hello Swift Community,

The [review](https://forums.swift.org/t/se-0471-improved-custom-serialexecutor-isolation-checking-for-concurrency-runtime/78834) of [SE-0471 "Improved Custom SerialExecutor isolation checking for Concurrency Runtime"](https://github.com/swiftlang/swift-evolution/blob/main/proposals/0471-SerialExecutor-isIsolated.md) concluded on April 29, 2025. The proposal underwent two modifications during the extended review period:

- The `isIsolatingCurrentContext` property now produces a `Bool?` to express the case where the serial executor cannot tell whether it is executing
- The `Actor.executor` property was added to make it possible to use the new functionality on an actor safely.

The Language Steering Group has decided to **accept** with these changes.

Thank you,  
Doug Gregor, Review Manager