# An unexpected \`Sendable\` pitfall

**URL:** <https://forums.swift.org/t/an-unexpected-sendable-pitfall/81012>\
**Category:** Using Swift\
**Created:** [July 9, 2025, 10:37am UTC](https://forums.swift.org/t/an-unexpected-sendable-pitfall/81012 "2025-07-09T10:37:39Z")\
**Posts on this page:** 1\
**Showing post:** 4

<div class="post-metadata">

**Author:** ![Nickolas\_Pohilets](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/nickolas_pohilets/32/10659_2.png) [@Nickolas\_Pohilets](https://forums.swift.org/u/Nickolas_Pohilets)\
**Post date:** [July 12, 2025, 3:46pm UTC](https://forums.swift.org/t/an-unexpected-sendable-pitfall/81012/4 "2025-07-12T15:46:07Z")

</div>

IIUC, there are no plans to implement this.

Down the thread @Douglas_Gregor mentions that he was thinking of a limited solution that wouldn't actually work in general case:

> [@SE-0470: Global-actor isolated conformances](https://forums.swift.org/t/se-0470-global-actor-isolated-conformances/78704/10):
>
> Oh, this is tricky. I was thinking of it as something we would do specifically for the casts themselves, because changing the identity of existential types (such as `any Sendable & P` is distinct from `any P` at runtime) can have far-ranging implications. But that means that my approach here _won't_ fix this existing issue with marker protocols.

---

_[View the full topic](https://forums.swift.org/t/an-unexpected-sendable-pitfall/81012)._