Rollup of 17 pull requests by JonathanBrouwer · Pull Request #164322 · rust-lang/rust

JonathanBrouwer · 2026-10-14T17:29:41Z

Successful merges:

Recover missing turbofish for lifetime arguments in expression position #162749 (Recover missing turbofish for lifetime arguments in expression position)
Add a new rustc_show_spans internal attribute #164165 (Add a new rustc_show_spans internal attribute)
Prefer WriteConsoleW for stdout on Windows #164170 (Prefer WriteConsoleW for stdout on Windows)
Implement better resolution for delegation Self mapping field #164208 (Implement better resolution for delegation Self mapping field)
test DSL eagerly handle false constraints #164255 (test DSL eagerly handle false constraints)
Document zero-sized allocations properly for Box and Vec #163230 (Document zero-sized allocations properly for Box and Vec)
Fix fudging #163442 (Fix fudging)
Parse move exprs as a bottom expr instead of a prefix expr #163940 (Parse move exprs as a bottom expr instead of a prefix expr)
document some quirks around directory symlinks on Windows #164079 (document some quirks around directory symlinks on Windows)
Fix diagnostic::on_unknown format placeholder for paths in expressions and type paths #164178 (Fix diagnostic::on_unknown format placeholder for paths in expressions and type paths)
Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same #164219 (Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same)
rustdoc: Improvements for rustc_must_implement_one_of #164266 (rustdoc: Improvements for rustc_must_implement_one_of)
Add regression test for #155977 #164272 (Add regression test for [ICE]: could not normalize Binder #155977)
Add regression test for hang in overlap check with GAT alias #164287 (Add regression test for hang in overlap check with GAT alias)
Remove the span_use_eq_ctxt lint #164292 (Remove the span_use_eq_ctxt lint)
fix issue number for feature(unsized_const_params) #164301 (fix issue number for feature(unsized_const_params))
point at the opaque when its hidden type cannot be inferred #164309 (point at the opaque when its hidden type cannot be inferred)

…handle-cache, r=aapoalas" This reverts commit 556c0e6, reversing changes made to 2cb8b18.

This new attribute is a first step for solving issue 126763. Now, we can easily test out where spans end up, particularly useful for ensuring that spans end up in the best suitable macro context.

…uct expr

…enerate links to the mentioned methods

…are none if the `rustc_must_implement_one_of` attribute is present

…test improvements for same

PR 163857 changed the span representation and reduced `eq_ctxt` to a trivial equality check, which means `span_a.ctxt() == span_b.ctxt()` is now an ok alternative to `span_a.eq_ctxt(span_b)`. This commit removes `span_use_eq_ctxt` because it's no longer necessary. `eq_ctxt` remains because removing it would cause some churn; it might be worth doing as a follow-up.

This drops the `GetConsoleOutputCP` call, which would otherwise do an RPC to the console server (= slow). This leaves us with `is_console` which was using another RPC via `GetConsoleMode` (= doubly slow). On Windows 8+ we can just use `NtQueryVolumeInformationFile()` to test for `FILE_DEVICE_CONSOLE`, resulting in a ~2x console stdout speedup.

the note for an uninferable hidden type now points at the opaque definition, unless the error already points inside it

@estebank

…rcote Recover missing `turbofish` for `lifetime` arguments in expression position Fixes rust-lang#162656. `Struct<'a> { .. }` and `f<'_>()` were parsed as a `<` comparison whose RHS is a label, producing a cascade of unrelated errors. `parse_path_segment` now accepts `<` followed by a lifetime and `>`/`,` in expression paths, emits one "use `::<...>`" suggestion, and parses the args normally.Since the recovery is inside the path parser, `path.span` and chained forms (`::new()`, `.method()`, `?`) work without AST fix-ups or new `Parser` state; it is guarded by `may_recover()`. cc @estebank

@petrochenkov

…-attr, r=petrochenkov Add a new `rustc_show_spans` internal attribute This new internal attribute is a first step for solving rust-lang#126763. Given the code: ```rust #![feature(rustc_attrs)] mod x { pub const Y: u8 = 1; } macro_rules! path { ($a:tt, $b:tt) => { let _ = $a::$b; }; } #[rustc_show_spans(path)] fn no_macro() { let _ = x::Y; } #[rustc_show_spans(path)] fn path_bug() { path!(x, Y); } ``` We can now report the spans and thus show the bug of the span not falling inside the macro context: ``` note: showing the spans of the path --> test.rs:8:25 | 8 | fn no_macro() { let _ = x::Y; } | ^^^^ note: showing the spans of the path --> test.rs:11:23 | 11 | fn path_bug() { path!(x, Y); } | ^^^^ ``` r? @petrochenkov

…sole, r=ChrisDenton Prefer WriteConsoleW for stdout on Windows This PR reverts rust-lang#159562 and changes stdout on Windows such that all writes use `WriteConsoleW` _if_ stdout refers to a console. This drops the `GetConsoleOutputCP` call, which would otherwise do an RPC to the console server (= slow). This leaves us with `is_console` which was using another RPC via `GetConsoleMode` (= doubly slow). On Windows 8+ we can just use `NtQueryVolumeInformationFile()` to test for `FILE_DEVICE_CONSOLE`, resulting in a ~2x console stdout speedup. ### Linewise output of `RELEASES.md`: Output | Version | lines/s | MB/s | Speedup --------|----------|--------:|------:|-------- console | 1.99.0 | 31526 | 1.79 | console | nightly | 29251 | 1.66 | console | **this** | 67294 | 3.82 | 2.13x `NUL` | 1.99.0 | 784311 | 44.50 | `NUL` | nightly | 776529 | 44.06 | `NUL` | **this** | 1141618 | 64.78 | 1.46x The console output speedup is very noticeable here, as the time to run drops from 0.6s to just 0.25s. ### 128KiB chunked passthrough of `enwik8`: Output | Version | MB/s | Speedup --------|----------|--------:|-------- console | 1.99.0 | 86.99 | console | nightly | 165.27 | 1.90x console | **this** | 165.61 | 1.90x `NUL` | 1.99.0 | 1123.82 | `NUL` | nightly | 1137.30 | `NUL` | **this** | 1289.35 | The limiting factor here is `MAX_BUFFER_SIZE` which deserves to be refactored in another PR in my opinion.

JonathanBrouwer · 2026-10-14T17:29:59Z

@bors r+ p=5 force

Trying commonly failed jobs
@bors try jobs=dist-various-1,test-various,test-x86_64-gnu-aux,test-x86_64-msvc-1,test-aarch64-apple-1,test-aarch64-apple-2,test-x86_64-mingw-1,test-i686-msvc,test-armhf-gnu,test-x86_64-gnu-llvm-22-3

rust-bors · 2026-10-14T17:30:03Z

📌 Commit c080453 has been approved by JonathanBrouwer

It is now in the queue for this repository.

Rollup of 17 pull requests try-job: dist-various-1 try-job: test-various try-job: test-x86_64-gnu-aux try-job: test-x86_64-msvc-1 try-job: test-aarch64-apple-1 try-job: test-aarch64-apple-2 try-job: test-x86_64-mingw-1 try-job: test-i686-msvc try-job: test-armhf-gnu try-job: test-x86_64-gnu-llvm-22-3

rust-bors · 2026-10-14T20:46:42Z

☀️ Try build successful (CI)
Build commit: c81a1a2 (c81a1a22f8ef8481f1f8c552262b286109730be7)
Base parent: f6c1107 (f6c1107f8be13e48465e12c0fd26e6a39fe18e4f)

rust-bors · 2026-10-14T22:00:28Z

☀️ Test successful - CI
Approved by: JonathanBrouwer
Duration: 3h 3m 25s
Pushing 7df8138 to main...

github-actions · 2026-10-14T22:03:44Z

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 f6c1107 (parent) -> 7df8138 (this PR)

Test differences

Show 1371 test diffs

Stage 1

[ui (polonius)] tests/ui/assumptions_on_binders/test-forall-evaluates-to-false.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/assumptions_on_binders/test-top-level-false-constraint.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/attributes/show_spans-nested-items.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/attributes/show_spans_macros.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/coercion/fudge-inference/fudge-eager-resolve-breakage-3.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/coherence/overlap-check-gat-alias-hang-151503.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/const-generics/ice-unevaluated.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/delegation/self-type-mapping-field-name.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name_foreign.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/move-expr/left-operand-of-dot-call-index-try.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/parser/recover/missing-turbofish-lifetime-macro.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/parser/recover/missing-turbofish-lifetime.rs: [missing] -> pass (J1)
[ui (polonius)] tests/ui/traits/next-solver/normalize/higher-ranked-param-env-normalization-155977.rs: [missing] -> pass (J1)
[ui] tests/ui/assumptions_on_binders/test-forall-evaluates-to-false.rs: [missing] -> pass (J2)
[ui] tests/ui/assumptions_on_binders/test-top-level-false-constraint.rs: [missing] -> pass (J2)
[ui] tests/ui/attributes/show_spans-nested-items.rs: [missing] -> pass (J2)
[ui] tests/ui/attributes/show_spans_macros.rs: [missing] -> pass (J2)
[ui] tests/ui/coercion/fudge-inference/fudge-eager-resolve-breakage-3.rs: [missing] -> pass (J2)
[ui] tests/ui/coherence/overlap-check-gat-alias-hang-151503.rs: [missing] -> pass (J2)
[ui] tests/ui/const-generics/ice-unevaluated.rs: [missing] -> pass (J2)
[ui] tests/ui/delegation/self-type-mapping-field-name.rs: [missing] -> pass (J2)
[ui] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name.rs: [missing] -> pass (J2)
[ui] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name_foreign.rs: [missing] -> pass (J2)
[ui] tests/ui/move-expr/left-operand-of-dot-call-index-try.rs: [missing] -> pass (J2)
[ui] tests/ui/parser/recover/missing-turbofish-lifetime-macro.rs: [missing] -> pass (J2)
[ui] tests/ui/parser/recover/missing-turbofish-lifetime.rs: [missing] -> pass (J2)
[ui] tests/ui/traits/next-solver/normalize/higher-ranked-param-env-normalization-155977.rs: [missing] -> pass (J2)
[crashes] tests/crashes/118603.rs: pass -> [missing] (J4)
[rustdoc-html] tests/rustdoc-html/trait-rustc_must_implement_one_of.rs: [missing] -> pass (J4)
[ui] tests/ui-fulldeps/internal-lints/span_use_eq_ctxt.rs: pass -> [missing] (J4)

Stage 2

[crashes] tests/crashes/118603.rs: pass -> [missing] (J0)
[ui] tests/ui/assumptions_on_binders/test-forall-evaluates-to-false.rs: [missing] -> pass (J3)
[ui] tests/ui/assumptions_on_binders/test-top-level-false-constraint.rs: [missing] -> pass (J3)
[ui] tests/ui/attributes/show_spans-nested-items.rs: [missing] -> pass (J3)
[ui] tests/ui/attributes/show_spans_macros.rs: [missing] -> pass (J3)
[ui] tests/ui/coercion/fudge-inference/fudge-eager-resolve-breakage-3.rs: [missing] -> pass (J3)
[ui] tests/ui/coherence/overlap-check-gat-alias-hang-151503.rs: [missing] -> pass (J3)
[ui] tests/ui/const-generics/ice-unevaluated.rs: [missing] -> pass (J3)
[ui] tests/ui/delegation/self-type-mapping-field-name.rs: [missing] -> pass (J3)
[ui] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name.rs: [missing] -> pass (J3)
[ui] tests/ui/diagnostic_namespace/on_unknown/expressions_and_paths_correct_mod_name_foreign.rs: [missing] -> pass (J3)
[ui] tests/ui/move-expr/left-operand-of-dot-call-index-try.rs: [missing] -> pass (J3)
[ui] tests/ui/parser/recover/missing-turbofish-lifetime-macro.rs: [missing] -> pass (J3)
[ui] tests/ui/parser/recover/missing-turbofish-lifetime.rs: [missing] -> pass (J3)
[ui] tests/ui/traits/next-solver/normalize/higher-ranked-param-env-normalization-155977.rs: [missing] -> pass (J3)
[ui] tests/ui-fulldeps/internal-lints/span_use_eq_ctxt.rs: pass -> [missing] (J5)
fs::tests::file_test_windows_fileext_trait_case_6: [missing] -> pass (J6)
[rustdoc-html] tests/rustdoc-html/trait-rustc_must_implement_one_of.rs: [missing] -> pass (J7)

Additionally, 1322 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 7df81381d027710708209f36b98d11b1c88f8d2e --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

test-x86_64-gnu-gcc-core-tests: 9m 37s -> 18m 50s (+95.8%)
test-i686-gnu-2: 1h 4m -> 1h 51m (+71.2%)
test-i686-gnu-nopt-2: 1h 25m -> 2h 25m (+70.2%)
test-x86_64-gnu-stdlib-semver-check: 11m 9s -> 17m 46s (+59.3%)
dist-apple-various: 1h 38m -> 2h 28m (+50.2%)
dist-riscv64-linux-musl: 1h -> 1h 29m (+47.2%)
test-x86_64-gnu-llvm-22-3: 1h 18m -> 1h 54m (+46.4%)
test-various: 1h 27m -> 2h 5m (+43.3%)
test-x86_64-gnu-tools: 48m 9s -> 1h 7m (+40.0%)
test-x86_64-msvc-ext1: 1h 47m -> 2h 28m (+38.1%)

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 · 2026-10-14T23:02:03Z

Finished benchmarking commit (7df8138): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

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Test differences

Stage 1

Stage 2

Job duration changes

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Overall result: ❌✅ regressions and improvements - please read:

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#162749 b85e04b Recover missing turbofish for lifetime arguments in expression position

#164165 382701a Add a new rustc_show_spans internal attribute

#164170 831bebc Prefer WriteConsoleW for stdout on Windows

#164208 ef2739e Implement better resolution for delegation Self mapping field

#164255 e6d819b test DSL eagerly handle false constraints

#163230 47ef034 Document zero-sized allocations properly for Box and Vec

#163442 beedcee Fix fudging

#163940 c7eb226 Parse move exprs as a bottom expr instead of a prefix expr

#164079 ddf9067 document some quirks around directory symlinks on Windows

#164178 c9fc3fa Fix diagnostic::on_unknown format placeholder for paths in expressions and type paths

#164219 5cf62aa Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same

#164266 4edec2f rustdoc: Improvements for rustc_must_implement_one_of

#164272 5671c4b Add regression test for #155977

#164287 8a370f5 Add regression test for hang in overlap check with GAT alias

#164292 8703bff Remove the span_use_eq_ctxt lint

#164301 a6952c9 fix issue number for feature(unsized_const_params)

#164309 bfc99ae point at the opaque when its hidden type cannot be inferred

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JonathanBrouwer commented Oct 14, 2026 •

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#162749 `b85e04b` Recover missing `turbofish` for `lifetime` arguments in expression position

#164165 `382701a` Add a new `rustc_show_spans` internal attribute

#164170 `831bebc` Prefer WriteConsoleW for stdout on Windows

#164208 `ef2739e` Implement better resolution for delegation `Self` mapping field

#164255 `e6d819b` test DSL eagerly handle false constraints

#163230 `47ef034` Document zero-sized allocations properly for `Box` and `Vec`

#163442 `beedcee` Fix fudging

#163940 `c7eb226` Parse move exprs as a bottom expr instead of a prefix expr

#164079 `ddf9067` document some quirks around directory symlinks on Windows

#164178 `c9fc3fa` Fix `diagnostic::on_unknown` format placeholder for paths in expressions and type paths

#164219 `5cf62aa` Windows FileExt trait doesn't need to handle ErrorKind::Interrupted; test improvements for same

#164266 `4edec2f` rustdoc: Improvements for `rustc_must_implement_one_of`

#164272 `5671c4b` Add regression test for #155977

#164287 `8a370f5` Add regression test for hang in overlap check with GAT alias

#164292 `8703bff` Remove the `span_use_eq_ctxt` lint

#164301 `a6952c9` fix issue number for feature(unsized_const_params)

#164309 `bfc99ae` point at the opaque when its hidden type cannot be inferred