T-compiler Meeting Agenda 2025-10-09

--- tags: weekly, rustc type: docs note_id: znD7hBT3TBSH7UUgFzFKvg --- # T-compiler Meeting Agenda 2025-10-09 ## Announcements - Reminder: if you see a PR/issue that seems like there might be legal implications due to copyright/IP/etc, please let us know (or at least message @_**davidtwco** or @_**Wesley Wiser** so we can pass it along). - Mentioning [MCP#919](https://github.com/rust-lang/compiler-team/issues/919). Discussion on Zulip, [from this message](https://rust-lang.zulipchat.com/#narrow/channel/233931-t-compiler.2Fmajor-changes/topic/target.20tier.203.20support.20for.20hexagon-unknown.E2.80.A6.20compiler-team.23919/near/543658888) - Proponent contacted Qualcomm legal team ([comment](https://rust-lang.zulipchat.com/#narrow/channel/233931-t-compiler.2Fmajor-changes/topic/target.20tier.203.20support.20for.20hexagon-unknown.E2.80.A6.20compiler-team.23919/near/543771438) and following) with the quesiton in the thread ### Other WG meetings - WG-async design meeting <time:2025-10-0925T19:00:00+02:00> ## MCPs/FCPs - New MCPs (take a look, see if you like them!) - "Turn emscripten-wasm-eh unwinding ABI on by default" [compiler-team#920](https://github.com/rust-lang/compiler-team/issues/920) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Turn.20emscripten-wasm-eh.20unwinding.20ABI.20on.20.E2.80.A6.20compiler-team.23920)) - "Rename `hexagon-unknown-{none-elf,linux-musl}` targets" [compiler-team#921](https://github.com/rust-lang/compiler-team/issues/921) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Rename.20.60hexagon-unknown-.7Bnone-elf.2Clinux-m.E2.80.A6.20compiler-team.23921)) - "Optimize `repr(Rust)` enums by omitting tags in more cases involving uninhabited variants." [compiler-team#922](https://github.com/rust-lang/compiler-team/issues/922) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Optimize.20.60repr.28Rust.29.60.20enums.20by.20omitting.20t.E2.80.A6.20compiler-team.23922)) - "Run main rust-analyzer tests in rust-lang/rust CI" [compiler-team#923](https://github.com/rust-lang/compiler-team/issues/923) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Run.20main.20rust-analyzer.20tests.20in.20rust-lang.E2.80.A6.20compiler-team.23923)) - "Remove diagnostic translation infrastructure" [compiler-team#924](https://github.com/rust-lang/compiler-team/issues/924) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Remove.20diagnostic.20translation.20infrastruct.E2.80.A6.20compiler-team.23924)) - concern: [people-like-structs](https://github.com/rust-lang/compiler-team/issues/924#issuecomment-3377416128) - Old MCPs (not seconded, take a look) - "Compile UI tests as libraries by default" [compiler-team#842](https://github.com/rust-lang/compiler-team/issues/842) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Compile.20UI.20tests.20as.20libraries.20by.20default.20compiler-team.23842)) (last review activity: 7 months ago) - "Unify ui test inline error annotation style" [compiler-team#859](https://github.com/rust-lang/compiler-team/issues/859) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Unify.20ui.20test.20inline.20error.20annotation.20sty.E2.80.A6.20compiler-team.23859)) (last review activity: 2 months ago) - "Promote tier 3 riscv32 ESP-IDF targets to tier 2" [compiler-team#864](https://github.com/rust-lang/compiler-team/issues/864) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Promote.20tier.203.20riscv32.20ESP-IDF.20targets.20to.E2.80.A6.20compiler-team.23864)) (last review activity: 3 months ago) - "Add support for specifying split-debuginfo=unpacked output directory" [compiler-team#871](https://github.com/rust-lang/compiler-team/issues/871) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20support.20for.20specifying.20split-debuginf.E2.80.A6.20compiler-team.23871)) (last review activity: 5 months ago) - "Relative VTables for Rust" [compiler-team#903](https://github.com/rust-lang/compiler-team/issues/903) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Relative.20VTables.20for.20Rust.20compiler-team.23903)) (last review activity: 2 months ago) - "Experiment with replacing specialization in libcore with downcasting" [compiler-team#904](https://github.com/rust-lang/compiler-team/issues/904) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Experiment.20with.20replacing.20specialization.20.E2.80.A6.20compiler-team.23904)) (last review activity: 2 months ago) - Pending FCP requests (check your boxes!) - merge: [Promote `riscv64a23-unknown-linux-gnu` to Tier 2 with host tools (compiler-team#910)](https://github.com/rust-lang/compiler-team/issues/910#issuecomment-3302421999) - @_**|124288** @_**|125250** @_**|119031** @_**|426609** @_**|116122** @_**|116118** @_**|259697** @_**|444933** - concerns: [no-hardware-available (by davidtwco)](https://github.com/rust-lang/compiler-team/issues/910#issuecomment-3302832854) [unclear-justification (by jieyouxu)](https://github.com/rust-lang/compiler-team/issues/910#issuecomment-3305030219) - merge: [sanitizers: Stabilize AddressSanitizer and LeakSanitizer for the Tier 1 targets (rust#123617)](https://github.com/rust-lang/rust/pull/123617#issuecomment-2135121317) - no pending checkboxes - concerns: [stabilization-scope (by wesleywiser)](https://github.com/rust-lang/rust/pull/123617#issuecomment-2192330122) - merge: [Impls and impl items inherit `dead_code` lint level of the corresponding traits and trait items (rust#144113)](https://github.com/rust-lang/rust/pull/144113#issuecomment-3382027300) - @_**|116009** @_**|614535** @_**|125270** - no pending concerns - merge: [Stabilize -Zno-jump-tables into -Cjump-tables=bool (rust#145974)](https://github.com/rust-lang/rust/pull/145974#issuecomment-3349582314) - @**|124288** @**|119031** @**|426609** - no pending concerns - merge: [Stabilize stack-protector (rust#146369)](https://github.com/rust-lang/rust/pull/146369#issuecomment-3271397169) - @_**|116266** @_**|119031** @_**|426609** @_**|116122** @_**|444933** - concerns: [mitigation-enforcement (by Noratrieb)](https://github.com/rust-lang/rust/pull/146369#issuecomment-3286402251) - Things in FCP (make sure you're good with it) - "Proposal for Adapt Stack Protector for Rust" [compiler-team#841](https://github.com/rust-lang/compiler-team/issues/841) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/.28My.20major.20change.20proposal.29.20compiler-team.23841)) - concern: [lose-debuginfo-data](https://github.com/rust-lang/compiler-team/issues/841#issuecomment-2683562830) - concern: [inhibit-opts](https://github.com/rust-lang/compiler-team/issues/841#issuecomment-2683562830) - concern: [impl-at-mir-level](https://github.com/rust-lang/compiler-team/issues/841#issuecomment-2683562830) - "Proposal for a dedicated test suite for the parallel frontend" [compiler-team#906](https://github.com/rust-lang/compiler-team/issues/906) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Proposal.20for.20a.20dedicated.20test.20suite.20for.20t.E2.80.A6.20compiler-team.23906)) - concern: [name-a-specific-reason](https://github.com/rust-lang/compiler-team/issues/906#issuecomment-3137732970) - concern: [can-we-just-enhance-ui-suite](https://github.com/rust-lang/compiler-team/issues/906#issuecomment-3137762379) - "Promote armv7a-none-eabihf to Tier 2" [compiler-team#913](https://github.com/rust-lang/compiler-team/issues/913) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Promote.20armv7a-none-eabihf.20to.20Tier.202.20compiler-team.23913)) - "Promote armv8r-none-eabihf to Tier 2" [compiler-team#914](https://github.com/rust-lang/compiler-team/issues/914) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Promote.20armv8r-none-eabihf.20to.20Tier.202.20compiler-team.23914)) - "target tier 3 support for hexagon-unknown-qurt" [compiler-team#919](https://github.com/rust-lang/compiler-team/issues/919) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/target.20tier.203.20support.20for.20hexagon-unknown.E2.80.A6.20compiler-team.23919)) - "Remove current code for embedding command-line args in PDB" [rust#147022](https://github.com/rust-lang/rust/pull/147022) - Accepted MCPs - "Demote both armebv7r-none-* targets" [compiler-team#912](https://github.com/rust-lang/compiler-team/issues/912) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Demote.20both.20armebv7r-none-.2A.20targets.20compiler-team.23912)) - MCPs blocked on unresolved concerns - "WebAssembly for procedural macros" [compiler-team#876](https://github.com/rust-lang/compiler-team/issues/876) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/WebAssembly.20for.20procedural.20macros.20compiler-team.23876)) (last review activity: 2 months ago) - concern: [proposal-wording](https://github.com/rust-lang/compiler-team/issues/876#issuecomment-3078140906) - "Promote `armv7-unknown-linux-musleabihf` to tier 2 with host tools" [compiler-team#888](https://github.com/rust-lang/compiler-team/issues/888) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Promote.20.60armv7-unknown-linux-musleabihf.60.20.E2.80.A6.20compiler-team.23888)) (last review activity: 2 months ago) - concern: [lack-of-maintainers](https://github.com/rust-lang/compiler-team/issues/888#issuecomment-3035366625) - "Basic target naming rules" [compiler-team#850](https://github.com/rust-lang/compiler-team/issues/850) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Basic.20target.20naming.20rules.20compiler-team.23850)) (last review activity: about 2 days ago) - concern: [wont-stop-target-names-from-proliferating](https://github.com/rust-lang/compiler-team/issues/850#issuecomment-3074434152) - "Add hygiene attributes to compile expanded source code" [compiler-team#692](https://github.com/rust-lang/compiler-team/issues/692) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20option.20to.20compile.20expanded.20ASTs.20for.20h.E2.80.A6.20compiler-team.23692)) (last review activity: 3 months ago) - concern: [path-to-stabilization](https://github.com/rust-lang/compiler-team/issues/692#issuecomment-2980212568) - "Rename "dylib" crate type to "rdylib" (keep old name but deprecate it), and maybe do the same for "staticlib" → "cstaticlib"" [compiler-team#825](https://github.com/rust-lang/compiler-team/issues/825) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Rename.20.22dylib.22.20create.20type.20to.20.22rdylib.22.20.28k.E2.80.A6.20compiler-team.23825)) (last review activity: 3 months ago) - concern: [needs-a-blog-post](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024360549) - concern: [needs-a-sufficiently-long-deprecation-timeline](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024361071) - concern: [broad-change-needs-tlang-buy-in-possibly-fcp](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024361199) - Finalized FCPs (disposition merge) - "Fix accidental type inference in array coercion" [rust#140283](https://github.com/rust-lang/rust/pull/140283) - "Fix backtraces with `-C panic=abort` on linux; emit unwind tables by default" [rust#143613](https://github.com/rust-lang/rust/pull/143613) - Other teams finalized FCPs - "Fix accidental type inference in array coercion" [rust#140283](https://github.com/rust-lang/rust/pull/140283) - "Allow `&raw [mut | const]` for union field in safe code" [rust#141469](https://github.com/rust-lang/rust/pull/141469) - "Do not materialise X in [X; 0] when X is unsizing a const" [rust#145277](https://github.com/rust-lang/rust/pull/145277) - "Allow borrowing array elements from packed structs with ABI align <= packed align" [rust#145419](https://github.com/rust-lang/rust/pull/145419) - "Reject invalid literal suffixes in tuple indexing, tuple struct indexing, and struct field name position" [rust#145463](https://github.com/rust-lang/rust/pull/145463) - "Opportunistically split `!=` to successfully parse never type" [rust#145536](https://github.com/rust-lang/rust/pull/145536) - "docs(style): Specify the frontmatter style" [rust#145617](https://github.com/rust-lang/rust/pull/145617) - "Stabilize `std::panic::Location::file_as_c_str`" [rust#145664](https://github.com/rust-lang/rust/pull/145664) - "the `#[track_caller]` shim should not inherit `#[no_mangle]`" [rust#145724](https://github.com/rust-lang/rust/pull/145724) - "Deny-by-default never type lints" [rust#146167](https://github.com/rust-lang/rust/pull/146167) - "Allow specifying multiple bounds for same associated item, except in trait objects" [rust#146593](https://github.com/rust-lang/rust/pull/146593) ## Backport nominations [T-compiler beta](https://github.com/rust-lang/rust/issues?q=is%3Apr+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-compiler) / [T-compiler stable](https://github.com/rust-lang/rust/issues?q=is%3Apr+label%3Astable-nominated+-label%3Astable-accepted+label%3AT-compiler) - :beta: "Don't normalize higher-ranked assumptions if they're not used" [rust#147299](https://github.com/rust-lang/rust/pull/147299) - Authored by compiler-errors - No voting Zulip topics :shrug:, backports need to be decided here - Fixes #147244 and #147285 (2 P-high stable regressions)  - :beta: "Fix target list of `link_section`" [rust#147418](https://github.com/rust-lang/rust/pull/147418) - Authored by JonathanBrouwer - Fixes an annoying and confusing warning from #147411 - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23147418.3A.20beta-nominated/near/543410779), in favor - :stable: "Don't normalize higher-ranked assumptions if they're not used" [rust#147299](https://github.com/rust-lang/rust/pull/147299) - Authored by compiler-errors  [T-types beta](https://github.com/rust-lang/rust/issues?q=is%3Apr+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-types) / [T-types stable](https://github.com/rust-lang/rust/issues?q=is%3Apr+label%3Astable-nominated+-label%3Astable-accepted+label%3AT-types) - :beta: and :stable: "Don't normalize higher-ranked assumptions if they're not used" [rust#147299](https://github.com/rust-lang/rust/pull/147299) - Discussed above ## PRs S-waiting-on-t-compiler [T-compiler](https://github.com/rust-lang/rust/pulls?q=is%3Aopen+label%3AS-waiting-on-t-compiler) - No PRs waiting on `T-compiler` this time. - [Issues in progress or waiting on other teams](https://hackmd.io/XYr1BrOWSiqCrl8RCWXRaQ) ## Issues of Note ### Short Summary - [0 T-compiler P-critical issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-critical) - [0 of those are unassigned](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-critical+no%3Aassignee) - [59 T-compiler P-high issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high) - [40 of those are unassigned](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high+no%3Aassignee) - [1 P-critical, 4 P-high, 3 P-medium, 0 P-low regression-from-stable-to-beta](https://github.com/rust-lang/rust/labels/regression-from-stable-to-beta) - [0 P-critical, 0 P-high, 1 P-medium, 1 P-low regression-from-stable-to-nightly](https://github.com/rust-lang/rust/labels/regression-from-stable-to-nightly) - [0 P-critical, 30 P-high, 100 P-medium, 25 P-low regression-from-stable-to-stable](https://github.com/rust-lang/rust/labels/regression-from-stable-to-stable) - "Coverage behavioral changes on #[derive] lines" [rust#147434](https://github.com/rust-lang/rust/issues/147434) - Question: what are our guarantees about code `llvm-cov`? - See [previous discussion](https://rust-lang.zulipchat.com/#narrow/channel/241545-t-release/topic/llvm-tools.20stabilization/near/421067194) about `llvm-tools` (from last year, though) ### P-critical [T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AP-critical+label%3AT-compiler) - No `P-critical` issues for `T-compiler` this time. [T-types](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AP-critical+label%3AT-types) - No `P-critical` issues for `T-types` this time. ### P-high regressions [P-high beta regressions](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3Aregression-from-stable-to-beta+label%3AP-high+-label%3AT-infra+-label%3AT-libs+-label%3AT-libs-api+-label%3AT-release+-label%3AT-rustdoc+-label%3AT-core) - "`alloc-variant-zeroed` causing issues with LTO" [rust#145995](https://github.com/rust-lang/rust/issues/145995) - "Duplicate warning on some attributes with wrong targets" [rust#147417](https://github.com/rust-lang/rust/issues/147417) [Unassigned P-high nightly regressions](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3Aregression-from-stable-to-nightly+label%3AP-high+no%3Aassignee+-label%3AT-infra+-label%3AT-libs+-label%3AT-libs-api+-label%3AT-release+-label%3AT-rustdoc+-label%3AT-core+) - No unassigned `P-high` nightly regressions this time. ## Performance logs > [triage logs for 2025-10-06](https://github.com/rust-lang/rustc-perf/blob/master/triage/2025/2025-10-06.md) Largely a positive week. Big win coming from avoiding unnecessary work for debug log in [#147293](https://github.com/rust-lang/rust/pull/147293), and another one for rustdoc from optimized span representation for highlighter [#147189](https://github.com/rust-lang/rust/pull/147189). Lots of noisy results otherwise. Triage done by **@panstromek**. Revision range: [8d72d3e1..1a3cdd34](https://perf.rust-lang.org/?start=8d72d3e1e96f58ca10059a6bb6e8aecba4a0e9cd&end=1a3cdd34629306fa67624eaa60d73687e7fcf855&absolute=false&stat=instructions%3Au) **Summary**: | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:---------------:|:-----:| | Regressions (primary) | 0.5% | [0.2%, 2.0%] | 10 | | Regressions (secondary) | 0.4% | [0.0%, 0.8%] | 50 | | Improvements (primary) | -1.3% | [-5.3%, -0.2%] | 147 | | Improvements (secondary) | -1.3% | [-12.7%, -0.1%] | 111 | | All (primary) | -1.2% | [-5.3%, 2.0%] | 157 | 6 Regressions, 3 Improvements, 6 Mixed; 8 of them in rollups 40 artifact comparisons made in total #### Regressions Rollup of 7 pull requests [#147140](https://github.com/rust-lang/rust/pull/147140) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=772f380092b30680313b70a622cafc17f03e6bff&end=7af913fc90968844286e5ff6675ab66afa98cdc6&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 0.2% | [0.1%, 0.3%] | 6 | | Regressions (secondary) | 0.2% | [0.0%, 0.4%] | 2 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 0.2% | [0.1%, 0.3%] | 6 | Based on perf runs on respective PRs, this seems to be https://github.com/rust-lang/rust/pull/133477. https://github.com/rust-lang/rust/pull/147092 was tested but regressions on that are noise and don't match this PR. Other PR's don't touch benchmarked code. This could also be noise, since the results somewhat fit a bimodal pattern and changes are tiny, but detailed results show increases in number of executed visibility related queries. Rollup of 5 pull requests [#147186](https://github.com/rust-lang/rust/pull/147186) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=a2db9280539229a3b8a084a09886670a57bc7e9c&end=42d009c0a9be0f7020a03f85dd47faa00d6d7bdf&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 3.0% | [3.0%, 3.0%] | 1 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 3.0% | [3.0%, 3.0%] | 1 | `clap_derive` bimodal noise Turn ProjectionElem::Subtype into CastKind::Subtype [#147055](https://github.com/rust-lang/rust/pull/147055) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=3369e82c6bc03c5cdb66f730dba6f738b74c8e1d&end=42b384ec0dfcd528d99a4db0a337d9188a9eecaa&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 3.0% | [3.0%, 3.0%] | 1 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 3.0% | [3.0%, 3.0%] | 1 | `clap_derive` bimodal noise Rollup of 9 pull requests [#147261](https://github.com/rust-lang/rust/pull/147261) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=4b9c62b4da3e17cee99d3d2052f1c576b188e2a8&end=94ecb52bbeeccc990545d4ebc9e9c35dcaf285e3&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 2.8% | [2.8%, 2.8%] | 1 | | Regressions (secondary) | 0.1% | [0.1%, 0.1%] | 1 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 2.8% | [2.8%, 2.8%] | 1 | `clap_derive` bimodal noise and something that looks like optimization shuffling in `coercions` (most of the changes are in the backend). This is a small change in secondary benchmark, so I don't think this is worth more investigation. Extending `#[rustc_force_inline]` to be applicable to inherent methods [#147231](https://github.com/rust-lang/rust/pull/147231) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=5c7ae0c7ed184c603e5224604a9f33ca0e8e0b36&end=8d603ef2879fd263f8e9aea340b4c035ed7973db&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 3.1% | [3.1%, 3.1%] | 1 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 3.1% | [3.1%, 3.1%] | 1 | `clap_derive` bimodal noise don't make empty ident when printing `'` ident from `extern "'"` [#147377](https://github.com/rust-lang/rust/pull/147377) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=828c2a9afccf3b3ff8133368cfbc8bfe526aaa4d&end=1a3cdd34629306fa67624eaa60d73687e7fcf855&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.9% | [0.8%, 1.0%] | 6 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | - | - | 0 | Perf results are noise. Looks like `wg-grammar` became bimodal recently. #### Improvements Rollup of 11 pull requests [#147220](https://github.com/rust-lang/rust/pull/147220) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=1e1a39441bd11aba541a48ba714d939490fc7b85&end=d4ae855111df8c7ee255bea4c112e74b7d72cf45&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:---------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.1% | [0.1%, 0.1%] | 1 | | Improvements (primary) | -1.3% | [-5.4%, -0.2%] | 19 | | Improvements (secondary) | -3.8% | [-12.6%, -0.2%] | 13 | | All (primary) | -1.3% | [-5.4%, -0.2%] | 19 | Test: Ambigious bindings in same namespace with the same res [#147196](https://github.com/rust-lang/rust/pull/147196) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=94ecb52bbeeccc990545d4ebc9e9c35dcaf285e3&end=5c7ae0c7ed184c603e5224604a9f33ca0e8e0b36&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -2.9% | [-2.9%, -2.9%] | 1 | | Improvements (secondary) | - | - | 0 | | All (primary) | -2.9% | [-2.9%, -2.9%] | 1 | Rollup of 6 pull requests [#147282](https://github.com/rust-lang/rust/pull/147282) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=8d603ef2879fd263f8e9aea340b4c035ed7973db&end=3b8665c5ab3aeced9b01672404c3764583e722ca&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -2.9% | [-2.9%, -2.9%] | 1 | | Improvements (secondary) | - | - | 0 | | All (primary) | -2.9% | [-2.9%, -2.9%] | 1 | #### Mixed Rollup of 6 pull requests [#147197](https://github.com/rust-lang/rust/pull/147197) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=42d009c0a9be0f7020a03f85dd47faa00d6d7bdf&end=fa3155a644dd62e865825087b403646be01d4cef&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.3% | [0.3%, 0.3%] | 1 | | Improvements (primary) | -1.5% | [-2.9%, -0.4%] | 3 | | Improvements (secondary) | -0.6% | [-1.2%, -0.3%] | 5 | | All (primary) | -1.5% | [-2.9%, -0.4%] | 3 | Improvements outweigh regressions. `coercions` regression also looks like noise. Split Bound index into Canonical and Bound [#147138](https://github.com/rust-lang/rust/pull/147138) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=42b384ec0dfcd528d99a4db0a337d9188a9eecaa&end=4b9c62b4da3e17cee99d3d2052f1c576b188e2a8&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.2% | [0.1%, 0.4%] | 7 | | Regressions (secondary) | 0.1% | [0.1%, 0.2%] | 11 | | Improvements (primary) | -1.0% | [-2.8%, -0.1%] | 4 | | Improvements (secondary) | -0.3% | [-1.1%, -0.0%] | 11 | | All (primary) | -0.3% | [-2.8%, 0.4%] | 11 | Improvements outweigh regressions, but some of those improvements are noise (clap-derive and syn). Main regressions match pre-merge results, so I assume this was deemed acceptable as a part of work on new solver, but I don't see any explicit justification. Introduce debuginfo to statements in MIR [#142771](https://github.com/rust-lang/rust/pull/142771) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=dd091003ace19d9556c647d87f7a9cd1e8dcc17e&end=8b6b15b877fbceb1ee5d9a5a4746e7515901574a&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.5% | [0.1%, 2.0%] | 9 | | Regressions (secondary) | 0.5% | [0.1%, 0.9%] | 43 | | Improvements (primary) | -0.3% | [-1.2%, -0.1%] | 101 | | Improvements (secondary) | -0.3% | [-1.0%, -0.1%] | 102 | | All (primary) | -0.3% | [-1.2%, 2.0%] | 110 | Improvements outweigh regressions. Some secondary regressions are just noise (`wg-grammar`), the biggest meaningful change seems to be `diesel` opt, as mentioned in https://github.com/rust-lang/rust/pull/142771#issuecomment-3367798805, due to more inlining, `syn` seems to be a similar case. Rollup of 10 pull requests [#147340](https://github.com/rust-lang/rust/pull/147340) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=99ca0ae87ba5571acee116ea83d1f9e88a7bf8d8&end=2cb4e7dce84fdebc0279159f1082f92b99299d87&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.1% | [0.1%, 0.1%] | 2 | | Regressions (secondary) | 0.2% | [0.1%, 0.3%] | 12 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -0.9% | [-1.0%, -0.8%] | 6 | | All (primary) | 0.1% | [0.1%, 0.1%] | 2 | Non-doc changes are mostly noise. Doc changes are not super clear to me. Even hello-world changed a tiny bit, so maybe this is just caused by the number of std changes? Some of those changes also mirror https://github.com/rust-lang/rust/pull/142771 dip, so it could also be noise. Either way, all doc changes are small and mostly secondary, I think we don't need to look more deeply into it. Avoid getting `dep_dep_node` unnecessarily. [#147293](https://github.com/rust-lang/rust/pull/147293) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=2cb4e7dce84fdebc0279159f1082f92b99299d87&end=227ac7c3cd486872d5c2352b3df02b571500e53a&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.9% | [0.8%, 1.0%] | 6 | | Improvements (primary) | -1.3% | [-3.5%, -0.2%] | 115 | | Improvements (secondary) | -1.1% | [-2.6%, -0.2%] | 61 | | All (primary) | -1.3% | [-3.5%, -0.2%] | 115 | `wg-grammar` regressions are noise, this is clearly a win otherwise. Rollup of 7 pull requests [#147363](https://github.com/rust-lang/rust/pull/147363) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=227ac7c3cd486872d5c2352b3df02b571500e53a&end=e2c96cc06bdbdbc6f59c7551194d6a742260d6ff&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.1% | [0.1%, 0.1%] | 1 | | Improvements (primary) | -0.5% | [-1.6%, -0.2%] | 6 | | Improvements (secondary) | -0.5% | [-1.6%, -0.0%] | 4 | | All (primary) | -0.5% | [-1.6%, -0.2%] | 6 | Improvements outweigh a small regression in secondary stress test. ## Nominated Issues [T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-compiler-nominated) - "Gate tests with the right edition" [rust#147498](https://github.com/rust-lang/rust/pull/147498) - Nominated by @**Jieyou Xu**, asks to check if it looks good - This PR implements what was discussed in [mcp#861](https://github.com/rust-lang/compiler-team/issues/861) (i.e. add capability to run tests, splitting by edition) [RFC](https://github.com/rust-lang/rfcs/issues?q=is%3Aopen+label%3AI-compiler-nominated) - No I-compiler-nominated RFCs this time. ### Oldest PRs waiting for review [T-compiler](https://github.com/rust-lang/rust/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-asc+label%3AS-waiting-on-review+draft%3Afalse+label%3AT-compiler) - "Revert "Change prefetch to avoid deadlock"" [rust#121910](https://github.com/rust-lang/rust/pull/121910) (last review activity: 19 months ago) - cc @**cjgillot** (just unblocked) - "feat: add `succinct-zkvm` os and target" [rust#138463](https://github.com/rust-lang/rust/pull/138463) (last review activity: 6 months ago) - cc @**Wesley Wiser** (here the [last discussion](https://rust-lang.zulipchat.com/#narrow/channel/238009-t-compiler.2Fmeetings/topic/.5Bweekly.5D.202025-04-24/near/514151632)) - "diagnostics: hide expansion of builtin-like macros" [rust#141314](https://github.com/rust-lang/rust/pull/141314) (last review activity: 4 months ago) - cc @**Vadim Petrochenkov** does your last comment mean that that PR can be closed? Next meetings' agenda draft: [hackmd link](https://hackmd.io/jMDUHDugQf6qe0jgFPdzHQ)

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