# Chapter 4 Warning: Reference to captured var 'countdown' in concurrently-executing code; this is an error in Swift 6

**URL:** <https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712>\
**Category:** Modern Concurrency in Swift\
**Created:** [August 12, 2022, 10:10pm UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712 "2022-08-12T22:10:08Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![penacristian](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/penacristian/32/105169_2.png) [@penacristian](https://forums.kodeco.com/u/penacristian)\
**Post date:** [August 12, 2022, 10:10pm UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/1 "2022-08-12T22:10:08Z")

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Swift 6 will not allow referencing or mutating the ‘countdown’ variable inside the scheduleTimer block.  
What would be a Swift 6-compatible solution?

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**Author:** ![icanzilb](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/icanzilb/32/109333_2.png) [@icanzilb](https://forums.kodeco.com/u/icanzilb)\
**Post date:** [August 13, 2022, 3:54am UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/2 "2022-08-13T03:54:15Z")

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Swift 6 isn’t released yet, I can’t speculate how the code would look like when released.

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**Author:** ![fyasin](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/fyasin/32/110937_2.png) [@fyasin](https://forums.kodeco.com/u/fyasin)\
**Post date:** [January 14, 2023, 8:34pm UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/3 "2023-01-14T20:34:50Z")

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As Swift 6 is released, could you please advise a solution

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**Author:** ![icanzilb](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/icanzilb/32/109333_2.png) [@icanzilb](https://forums.kodeco.com/u/icanzilb)\
**Post date:** [January 15, 2023, 4:24pm UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/4 "2023-01-15T16:24:46Z")

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It is still not released

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**Author:** ![djryanash](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/djryanash/32/108473_2.png) [@djryanash](https://forums.kodeco.com/u/djryanash)\
**Post date:** [January 8, 2024, 10:38am UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/5 "2024-01-08T10:38:25Z")

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I was hoping to find answers here but not very helpful.

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**Author:** ![marek5791](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/marek5791/32/102075_2.png) [@marek5791](https://forums.kodeco.com/u/marek5791)\
**Post date:** [August 25, 2024, 11:27am UTC](https://forums.kodeco.com/t/chapter-4-warning-reference-to-captured-var-countdown-in-concurrently-executing-code-this-is-an-error-in-swift-6/176712/6 "2024-08-25T11:27:46Z")

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Any update on this issue? Is there going to be an updated version of the book?