Clarify examples related to `Sync` and `SyncView` by tisonkun · Pull Request #162621 · rust-lang/rust

tisonkun · 2026-09-11T02:43:38Z

Updated examples to clarify the role of non-Sync fields and the functionality of SyncView.

This refers to #98407

rustbot · 2026-09-11T02:43:44Z

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pthariensflame · 2026-09-11T03:24:11Z

 /// ```
 ///
-/// `SyncView` ensures the struct is `Sync` without stripping the future of its
+/// `SyncView` makes the struct `Sync` without stripping the struct of its


Suggested change

/// `SyncView` makes the struct `Sync` without stripping the struct of its

/// `SyncView` makes the value `Sync` without stripping the struct of its

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Adopted. But I wonder if there is some references to teach more English or Rust's terminology to decide between words?

tbh I do feel like struct or type is more accurate here. value refers to a specific instantiation of a struct/type whose Sync-ness is entirely dependent on the syncness of its type. And it applies here especially since the "struct" in this case is contrasting with the "struct" mentioned a few lines earlier

Yeah, perhaps the best phrasing for both correctness and stylistic clarity would be “SyncView makes the type Sync without stripping it of its functionality…”.

JohnTitor · 2026-09-11T11:15:42Z

@bors squash

@tisonkun

* Clarify examples related to `Sync` and `SyncView` Updated examples to clarify the role of non-`Sync` fields and the functionality of `SyncView`. * Apply suggestion from @tisonkun * Update library/core/src/sync/sync_view.rs Co-authored-by: Laine Taffin Altman <alexanderaltman@me.com>

rust-bors · 2026-09-11T11:16:05Z

🔨 3 commits were squashed into ea39610.

JohnTitor

Thanks! @bors r+ rollup

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rust-bors · 2026-09-11T11:16:28Z

📌 Commit ea39610 has been approved by JohnTitor

It is now in the queue for this repository.

Clarify examples related to `Sync` and `SyncView` Updated examples to clarify the role of non-`Sync` fields and the functionality of `SyncView`. This refers to rust-lang#98407

JonathanBrouwer · 2026-09-11T13:41:53Z

💔 I suspect this PR failed tests as part of a rollup
@bors r-

After fixing the problem, consider running a try job for the failed job before re-approving.

Link to failure: #162636 (comment)

rust-bors · 2026-09-11T13:42:01Z

This pull request was unapproved.

This PR was contained in a rollup (#162636), which was unapproved.

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tisonkun · 2026-09-11T13:49:20Z

Weird .. Let me see ..

tisonkun · 2026-09-11T13:54:27Z

Add ignore-wasm to the second example that uses thread::spawn. This follows how atomic.rs's example does.

This should work now. cc @JohnTitor @JonathanBrouwer

JonathanBrouwer · 2026-09-11T13:55:17Z

@bors try jobs=test-various

Clarify examples related to `Sync` and `SyncView` try-job: test-various

rust-bors · 2026-09-11T16:06:42Z

☀️ Try build successful (CI)
Build commit: 24a3d70 (24a3d70870e3c8133d74346197944fa19fe23452)
Base parent: ada41e1 (ada41e1ce81819f01577c0ee40ccbd6fc41384e8)

JonathanBrouwer · 2026-09-11T16:12:23Z

@bors r=JohnTitor

rust-bors · 2026-09-11T16:12:26Z

📌 Commit f47f54d has been approved by JohnTitor

It is now in the queue for this repository.

Clarify examples related to `Sync` and `SyncView` Updated examples to clarify the role of non-`Sync` fields and the functionality of `SyncView`. This refers to rust-lang#98407

…uwer Rollup of 7 pull requests Successful merges: - #161413 (mir-transform: Remove `is_optimization_stage`) - #161430 (Re-export `core::fmt::NumBuffer` in `alloc` (and `std`)) - #162446 (Prevent `should-fail` to be used in `rustdoc-ui` testsuite) - #162621 (Clarify examples related to `Sync` and `SyncView`) - #162650 (Initialize mingw for all mingw targets) - #162651 (Remove needless test running instructions) - #162658 (Remove noras target docs mention)

Rollup merge of #162621 - tisonkun:patch-2, r=JohnTitor Clarify examples related to `Sync` and `SyncView` Updated examples to clarify the role of non-`Sync` fields and the functionality of `SyncView`. This refers to #98407

tgross35 · 2026-09-15T03:43:23Z

-/// ```
+/// ```ignore-wasm


This gives a "This example is not tested on wasm" warning in the docs https://doc.rust-lang.org/nightly/std/sync/struct.SyncView.html#examples which is a bit weird. Perhaps this and the original Atomic example should gate on target_has_threads instead?

This isn't super accurate anyway since we have wasm targets with threads and non-wasm targets without threads, it just happens that the wasm target in CI is the only thing we flag.

Thanks for your suggestion.

My concern is that target_has_threads doesn't guarantee that std::thread::spawn is supported.

For example, on wasm32-unknown-unknown, enabling +atomics makes singlethread() return false, which enables target_has_threads. However, std still selects the unsupported thread backend, where Thread::new always returns UNSUPPORTED_PLATFORM.

rustbot assigned JohnTitor Sep 11, 2026

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tisonkun mentioned this pull request Sep 11, 2026

Tracking Issue for SyncView #98407

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rust-bors Bot force-pushed the patch-2 branch from 3ab7a36 to ea39610 Compare September 11, 2026 11:16

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Rollup of 5 pull requests #162636

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tisonkun commented Sep 11, 2026

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f47f54d

tisonkun requested a review from JohnTitor September 11, 2026 13:53

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Auto merge of #162621 - tisonkun:patch-2, r=<try>

24a3d70

Clarify examples related to `Sync` and `SyncView` try-job: test-various

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This was referenced Sep 11, 2026

Rollup of 8 pull requests #162659

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Rollup of 7 pull requests #162664

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rust-bors Bot merged commit 69e0636 into rust-lang:main Sep 11, 2026
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tisonkun deleted the patch-2 branch September 11, 2026 22:30

tgross35 reviewed Sep 15, 2026

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	/// `SyncView` makes the struct `Sync` without stripping the struct of its
	/// `SyncView` makes the value `Sync` without stripping the struct of its

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