smart pointer (try_)map #144420

Qelxiros · 2025-07-24T21:13:53Z

Tracking issue: #144419

rustbot · 2025-07-25T00:12:56Z

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Qelxiros · 2025-07-25T00:12:59Z

As far as I can tell, the ICE here is because of the function signature of Box::try_map. The return type is equivalent to ChangeOutputType<...> from the ACP, but that definition is in core, so I implemented it manually here. However, when I add the same type alias to alloc, the ICE persists. Is there a workaround here that remains in the spirit of the ACP? Is this a known compiler bug?

joboet

I have no clue about the ICE – perhaps try filing an issue?

View changes since this review

library/alloc/src/boxed.rs

Qelxiros · 2025-09-04T13:55:27Z

I'm not sure how to move forward given the ICE (issue #146174).

@rustbot label +S-blocked

…iler-errors fix ICE when suggesting `::new` fixes rust-lang#146174 This code suggests to write `Foo::new(...)` when the user writes `Foo(...)` or `Foo { ... }` and the constructor is private, where `new` is some associated function that returns `Self`. When checking that the return type of `new` is `Self`, we need to instantiate the parameters of `new` with infer vars, so we don't end up with a type like `Box<$param(0)>` in a context that doesn't have any parameters. But then we can't use `normalize_erasing_late_bound_regions` anymore because that goes though a query that can't deal with infer vars. Since this is diagnostic-only code that is supposed to check for exactly `-> Self`, I think it's fine to just skip normalizing here, especially since The Correct WayTM would involve a probe and make this code even more complicated. Also, the code here does almost the same thing, and these suggestions can probably be unified in the future: https://github.com/rust-lang/rust/blob/4ca8078d37c53ee4ff8fb32b4453b915116f25b8/compiler/rustc_hir_typeck/src/method/suggest.rs#L2123-L2129 r? `@compiler-errors` cc `@Qelxiros` -- this should unblock rust-lang#144420

…iler-errors fix ICE when suggesting `::new` fixes rust-lang#146174 This code suggests to write `Foo::new(...)` when the user writes `Foo(...)` or `Foo { ... }` and the constructor is private, where `new` is some associated function that returns `Self`. When checking that the return type of `new` is `Self`, we need to instantiate the parameters of `new` with infer vars, so we don't end up with a type like `Box<$param(0)>` in a context that doesn't have any parameters. But then we can't use `normalize_erasing_late_bound_regions` anymore because that goes though a query that can't deal with infer vars. Since this is diagnostic-only code that is supposed to check for exactly `-> Self`, I think it's fine to just skip normalizing here, especially since The Correct WayTM would involve a probe and make this code even more complicated. Also, the code here does almost the same thing, and these suggestions can probably be unified in the future: https://github.com/rust-lang/rust/blob/4ca8078d37c53ee4ff8fb32b4453b915116f25b8/compiler/rustc_hir_typeck/src/method/suggest.rs#L2123-L2129 r? ```@compiler-errors``` cc ```@Qelxiros``` -- this should unblock rust-lang#144420

…iler-errors fix ICE when suggesting `::new` fixes rust-lang#146174 This code suggests to write `Foo::new(...)` when the user writes `Foo(...)` or `Foo { ... }` and the constructor is private, where `new` is some associated function that returns `Self`. When checking that the return type of `new` is `Self`, we need to instantiate the parameters of `new` with infer vars, so we don't end up with a type like `Box<$param(0)>` in a context that doesn't have any parameters. But then we can't use `normalize_erasing_late_bound_regions` anymore because that goes though a query that can't deal with infer vars. Since this is diagnostic-only code that is supposed to check for exactly `-> Self`, I think it's fine to just skip normalizing here, especially since The Correct WayTM would involve a probe and make this code even more complicated. Also, the code here does almost the same thing, and these suggestions can probably be unified in the future: https://github.com/rust-lang/rust/blob/4ca8078d37c53ee4ff8fb32b4453b915116f25b8/compiler/rustc_hir_typeck/src/method/suggest.rs#L2123-L2129 r? ````@compiler-errors```` cc ````@Qelxiros```` -- this should unblock rust-lang#144420

Rollup merge of #146217 - lukas-code:suggest-new-ice, r=compiler-errors fix ICE when suggesting `::new` fixes #146174 This code suggests to write `Foo::new(...)` when the user writes `Foo(...)` or `Foo { ... }` and the constructor is private, where `new` is some associated function that returns `Self`. When checking that the return type of `new` is `Self`, we need to instantiate the parameters of `new` with infer vars, so we don't end up with a type like `Box<$param(0)>` in a context that doesn't have any parameters. But then we can't use `normalize_erasing_late_bound_regions` anymore because that goes though a query that can't deal with infer vars. Since this is diagnostic-only code that is supposed to check for exactly `-> Self`, I think it's fine to just skip normalizing here, especially since The Correct WayTM would involve a probe and make this code even more complicated. Also, the code here does almost the same thing, and these suggestions can probably be unified in the future: https://github.com/rust-lang/rust/blob/4ca8078d37c53ee4ff8fb32b4453b915116f25b8/compiler/rustc_hir_typeck/src/method/suggest.rs#L2123-L2129 r? ````@compiler-errors```` cc ````@Qelxiros```` -- this should unblock #144420

Qelxiros · 2025-10-06T20:12:27Z

I'm not sure if the transmute is worth the readability from using Box::take, or if transmute is the only way to go from Box<MaybeUninit<T>> to Box<MaybeUninit>. Let me know if I'm missing something obvious.

joboet · 2025-10-07T12:22:25Z

I'm not sure if the transmute is worth the readability from using Box::take, or if transmute is the only way to go from Box<MaybeUninit<T>> to Box<MaybeUninit>. Let me know if I'm missing something obvious.

transmute is fine. You could also use Box::from_raw(Box::into_raw(..) as ..), if you prefer.

rustbot · 2025-10-07T13:59:11Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

Qelxiros · 2025-10-15T12:00:22Z

@rustbot ready
edit: ignore me, I got my labels confused and thought I'd forgotten to do this.

joboet

Great!
r=me with the nit applied

View changes since this review

joboet · 2025-10-31T13:46:09Z

library/alloc/src/sync.rs

+            && Arc::is_unique(&this)
+        {
+            unsafe {
+                use core::mem::MaybeUninit;


Please move this import to the top of the file.

joboet · 2025-10-31T13:46:50Z

library/alloc/src/sync.rs

+            && Arc::is_unique(&this)
+        {
+            unsafe {
+                use core::mem::MaybeUninit;


joboet · 2025-10-31T13:48:38Z

@bors delegate+

bors · 2025-10-31T13:48:42Z

✌️ @Qelxiros, you can now approve this pull request!

If @joboet told you to "r=me" after making some further change, please make that change, then do @bors r=@joboet

Qelxiros · 2025-10-31T14:14:44Z

@bors r=@joboet

bors · 2025-10-31T14:14:47Z

📌 Commit 9c5be67 has been approved by joboet

It is now in the queue for this repository.

…joboet smart pointer (try_)map Tracking issue: rust-lang#144419

Rollup of 7 pull requests Successful merges: - #139310 (add first HelenOS compilation targets) - #144420 (smart pointer (try_)map) - #145974 (Stabilize -Zno-jump-tables into -Cjump-tables=bool) - #147161 (implement VecDeque extend_from_within and prepend_from_within) - #147780 (Implement VecDeque::extract_if) - #148319 (docs: Fix argument names for `carrying_mul_add`) - #148322 (Enable file locking support in illumos) r? `@ghost` `@rustbot` modify labels: rollup

bors · 2025-10-31T17:09:51Z

⌛ Testing commit 9c5be67 with merge 82ae0ee...

bors · 2025-10-31T20:24:28Z

☀️ Test successful - checks-actions
Approved by: joboet
Pushing 82ae0ee to master...

github-actions · 2025-10-31T20:27:46Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 51f5892 (parent) -> 82ae0ee (this PR)

Test differences

Show 994 test diffs

994 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 82ae0ee6487e93bd6c05167ccb2ef3485fdbc890 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

dist-x86_64-apple: 7286.5s -> 8916.6s (+22.4%)
aarch64-apple: 6823.9s -> 8325.5s (+22.0%)
i686-gnu-nopt-1: 7847.9s -> 6802.5s (-13.3%)
test-various: 7105.6s -> 6160.7s (-13.3%)
x86_64-gnu-tools: 3474.8s -> 3068.9s (-11.7%)
x86_64-gnu-aux: 7047.9s -> 6274.4s (-11.0%)
x86_64-mingw-1: 9720.2s -> 10475.4s (+7.8%)
x86_64-gnu-nopt: 7244.4s -> 6719.1s (-7.3%)
dist-aarch64-linux: 6635.8s -> 6166.4s (-7.1%)
dist-ohos-x86_64: 4258.9s -> 3959.2s (-7.0%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2025-10-31T21:59:07Z

Finished benchmarking commit (82ae0ee): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results (primary 0.7%, secondary -1.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.7%	[0.7%, 0.7%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.9%	[-1.9%, -1.9%]	1
All ❌✅ (primary)	0.7%	[0.7%, 0.7%]	1

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

Results (secondary 0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Bootstrap: 474.501s -> 475.716s (0.26%)
Artifact size: 390.85 MiB -> 390.89 MiB (0.01%)

…boet smart pointer (try_)map Tracking issue: rust-lang#144419

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jul 24, 2025

Qelxiros mentioned this pull request Jul 24, 2025

Tracking Issue for smart pointer (try_)map #144419

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Qelxiros marked this pull request as ready for review July 25, 2025 00:12

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Complex function signature in Box method causes ICE #146174

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rustbot added the S-blocked Status: Blocked on something else such as an RFC or other implementation work. label Sep 4, 2025

lukas-code mentioned this pull request Sep 4, 2025

fix ICE when suggesting ::new #146217

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add {Box, (Unique){Rc, Arc}}::(try_)map

9c5be67

Qelxiros force-pushed the smart_pointer_try_map branch from 60cdf88 to 9c5be67 Compare October 31, 2025 14:14

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 31, 2025

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Oct 31, 2025

Rollup merge of rust-lang#144420 - Qelxiros:smart_pointer_try_map, r=…

44a9bc9

…joboet smart pointer (try_)map Tracking issue: rust-lang#144419

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Rollup of 7 pull requests #148331

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bors added the merged-by-bors This PR was explicitly merged by bors. label Oct 31, 2025

bors merged commit 82ae0ee into rust-lang:master Oct 31, 2025
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arbitrary_self_types: Split the Autoderef chain #146095

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replace box_new with lower-level intrinsics #148190

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Toolchain upgrade to nightly-2025-11-07 flux-rs/flux#1345

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makai410 pushed a commit to makai410/rust that referenced this pull request Nov 8, 2025

Auto merge of rust-lang#144420 - Qelxiros:smart_pointer_try_map, r=jo…

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…boet smart pointer (try_)map Tracking issue: rust-lang#144419

smart pointer (try_)map #144420

smart pointer (try_)map #144420

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