T-compiler Meeting Agenda 2025-07-03

--- tags: weekly, rustc type: docs note_id: mPODDOR8T2S4ol9Pje65og --- # T-compiler Meeting Agenda 2025-07-03 ## 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). ### Other WG meetings - WG-async design meeting <time:2025-07-03T19:00:00+02:00> - Stable MIR weekly meeting <time:2025-07-04T17:00:00+02:00> - WG-async planning meeting <time:2025-07-04T19:00:00+02:00> ## MCPs/FCPs - New MCPs (take a look, see if you like them!) - No new proposals this time. - Old MCPs (not seconded, take a look) - "Add Hotpatch flag" [compiler-team#745](https://github.com/rust-lang/compiler-team/issues/745) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20Hotpatch.20flag.20compiler-team.23745)) (last review activity: 8 months ago) - "Policy change around adding new unstable flags" [compiler-team#787](https://github.com/rust-lang/compiler-team/issues/787) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Policy.20change.20around.20adding.20new.20unstable.20.E2.80.A6.20compiler-team.23787)) (last review activity: 8 months ago) - "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: 3 months ago) - "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: 3 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: about 20 days 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: 2 months ago) - "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: about 34 days ago) - "Upgrade `*-linux-musl` targets to musl 1.2.5" [compiler-team#887](https://github.com/rust-lang/compiler-team/issues/887) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Upgrade.20.60.2A-linux-musl.60.20targets.20to.20musl.201.2E.E2.80.A6.20compiler-team.23887)) (last review activity: about 6 days ago) - "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: about 6 days ago) - Pending FCP requests (check your boxes!) - 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: [Add `target_env = "macabi"` and `target_env = "sim"` (rust#139451)](https://github.com/rust-lang/rust/pull/139451#issuecomment-2793613930) - @_**|116266** @_**|119031** @_**|353056** - no pending concerns - 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: [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) - concern: [lose-debuginfo-data](https://github.com/rust-lang/compiler-team/issues/841#issuecomment-2683562830) - "Make the UI test suite more amenable to multiple editions" [compiler-team#861](https://github.com/rust-lang/compiler-team/issues/861) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Run.20the.20UI.20test.20suite.20with.20multiple.20editi.E2.80.A6.20compiler-team.23861)) - concern: [edition-directive-meaning](https://github.com/rust-lang/compiler-team/issues/861#issuecomment-2796811016) - "Create `rustc_target::spec::Target` from a Builder" [compiler-team#890](https://github.com/rust-lang/compiler-team/issues/890) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Create.20.60rustc_target.3A.3Aspec.3A.3ATarget.60.20from.20.E2.80.A6.20compiler-team.23890)) - "Run more tests for rustc_codegen_gcc in the CI" [compiler-team#891](https://github.com/rust-lang/compiler-team/issues/891) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Run.20more.20tests.20for.20rustc_codegen_gcc.20in.20t.E2.80.A6.20compiler-team.23891)) - "Auto-create tracking issues for accepted MCPs" [compiler-team#892](https://github.com/rust-lang/compiler-team/issues/892) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Auto-create.20tracking.20issues.20for.20accepted.20.E2.80.A6.20compiler-team.23892)) - "Policy: Empower reviewers to reject burdensome PRs" [compiler-team#893](https://github.com/rust-lang/compiler-team/issues/893) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Policy.3A.20Reject.20low-effort.20AI-generated.20PRs.20compiler-team.23893)) - concern: [wait-for-some-discussions-to-settle](https://github.com/rust-lang/compiler-team/issues/893#issuecomment-3012233397) - Accepted MCPs - "setup typos check in CI (for rust repo)" [compiler-team#817](https://github.com/rust-lang/compiler-team/issues/817) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/setup.20typos.20check.20in.20CI.20.28for.20rust.20repo.29.20compiler-team.23817)) - "Add one more "late metadata"/"digest" file to rlib archives" [compiler-team#853](https://github.com/rust-lang/compiler-team/issues/853) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20one.20more.20.22late.20metadata.22.2F.22digest.22.20fil.E2.80.A6.20compiler-team.23853)) - "Constrain process required for some user-facing changes to lower support tier targets" [compiler-team#884](https://github.com/rust-lang/compiler-team/issues/884) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Constrain.20process.20required.20for.20some.20user-.E2.80.A6.20compiler-team.23884)) - "Expose `target_abi = "elfv{1,2}"` on `powerpc64-any-unixy-elfy` targets" [compiler-team#885](https://github.com/rust-lang/compiler-team/issues/885) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Expose.20.60target_abi.20.3D.20.22elfv.7B1.2C2.7D.22.60.20on.20.60pow.E2.80.A6.20compiler-team.23885)) - "use separate build directory for rust-analyzer to use" [compiler-team#889](https://github.com/rust-lang/compiler-team/issues/889) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/use.20separate.20build.20directory.20for.20rust-ana.E2.80.A6.20compiler-team.23889)) - MCPs blocked on unresolved concerns - "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: about 15 days 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: about 1 days ago) - concern: [needs-a-blog-post](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024360549) - concern: [broad-change-needs-tlang-buy-in-possibly-fcp](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024361199) - concern: [needs-a-sufficiently-long-deprecation-timeline](https://github.com/rust-lang/compiler-team/issues/825#issuecomment-3024361071) - Finalized FCPs (disposition merge) - "Use lld by default on `x86_64-unknown-linux-gnu` stable" [rust#140525](https://github.com/rust-lang/rust/pull/140525) - Other teams finalized FCPs - "Allow `#[must_use]` on associated types to warn on unused values in generic contexts" [rust#142590](https://github.com/rust-lang/rust/pull/142590) ## 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: "Reduce mismatched-lifetime-syntaxes suggestions to MaybeIncorrect" [rust#142980](https://github.com/rust-lang/rust/pull/142980) - Authored by shepmaster - Fixes #142998, fixes an annoying multiple lint suggestion generated from cargo fix ([comment](https://github.com/rust-lang/rust/pull/142980#issuecomment-3013518031)) - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23142980.3A.20beta-nominated/near/525704185), in favor - :beta: "Fix hang in --print=file-names in bootstrap" [rust#142928](https://github.com/rust-lang/rust/pull/142928) - This is a bootstrap backport, nominated by @**Wesley Wiser** (do we approve their backports as well?) - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/507486-t-infra.2Fbootstrap.2Fbackports/topic/.23142928.3A.20beta-nominated/near/525590742), in favor - :stable: "Do not ICE when reassigning in GatherLocalsVisitor on the bad path" [rust#140827](https://github.com/rust-lang/rust/pull/140827) - Authored by compiler-errors - Nominated by @_**cyrgani** in [comment](https://github.com/rust-lang/rust/pull/140827#issuecomment-3017028820) - Fixes a bunch of reported ICEs (#140785 #140730 #143188 #143209) but they don't seem critical - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23140827.3A.20stable-nominated/near/526290626), generally not in favor [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) - No beta nominations for `T-types` this time. - No stable nominations for `T-types` this time. ## PRs S-waiting-on-team [T-compiler](https://github.com/rust-lang/rust/pulls?q=is%3Aopen+label%3AS-waiting-on-team+label%3AT-compiler) - [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) - [58 T-compiler P-high issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high) - [39 of those are unassigned](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high+no%3Aassignee) - [0 P-critical, 0 P-high, 0 P-medium, 3 P-low regression-from-stable-to-beta](https://github.com/rust-lang/rust/labels/regression-from-stable-to-beta) - [0 P-critical, 2 P-high, 1 P-medium, 0 P-low regression-from-stable-to-nightly](https://github.com/rust-lang/rust/labels/regression-from-stable-to-nightly) - [0 P-critical, 33 P-high, 100 P-medium, 23 P-low regression-from-stable-to-stable](https://github.com/rust-lang/rust/labels/regression-from-stable-to-stable) ### 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) - No `P-high` beta regressions this time. [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 2025-06-30](https://github.com/rust-lang/rustc-perf/blob/master/triage/2025/2025-06-30.md) Lots of changes this week with results dominated by the 1-5% improvements from [#142941](https://github.com/rust-lang/rust/pull/142941) across lots of primary benchmarks in the suite. Triage done by **@simulacrum**. Revision range: [42245d34..ad3b7257](https://perf.rust-lang.org/?start=42245d34d22ade32b3f276dcf74deb826841594c&end=ad3b7257615c28aaf8212a189ec032b8af75de51&absolute=false&stat=instructions%3Au) **Summary**: | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:---------------:|:-----:| | Regressions (primary) | 2.9% | [0.2%, 21.6%] | 16 | | Regressions (secondary) | 1.5% | [0.1%, 13.5%] | 38 | | Improvements (primary) | -0.9% | [-4.5%, -0.1%] | 99 | | Improvements (secondary) | -6.2% | [-67.9%, -0.1%] | 100 | | All (primary) | -0.4% | [-4.5%, 21.6%] | 115 | 3 Regressions, 6 Improvements, 5 Mixed; 4 of them in rollups 39 artifact comparisons made in total #### Regressions Rollup of 10 pull requests [#143091](https://github.com/rust-lang/rust/pull/143091) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=13c46fd0b089360922a557d8e18a63a2c41dfbeb&end=fe5f3dedf7b4d6bea2cadb17343f747d70b4c66b&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 2.1% | [0.1%, 2.7%] | 7 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -0.1% | [-0.1%, -0.1%] | 1 | | All (primary) | - | - | 0 | Regressions in ctfe and match stress tests, trying to find the PR that introduced them in case there's obvious tweaks, but not particularly noteworthy given the limited impact. Rollup of 9 pull requests [#143116](https://github.com/rust-lang/rust/pull/143116) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=bdaba05a953eb5abeba0011cdda2560d157aed2e&end=d41e12f1f4e4884c356f319b881921aa37040de5&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 1.1% | [0.9%, 1.3%] | 9 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | - | - | 0 | Regressions are in the `coercions` stress test, not clear which of the rolled up PRs caused it. Started one candidate perf run. Rollup of 11 pull requests [#143173](https://github.com/rust-lang/rust/pull/143173) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=dddd7ab96229ea5f2ca96afcb5984a9831393a13&end=5ca574e85b67cec0a6fc3fddfe398cbe676c9c69&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 0.5% | [0.3%, 0.7%] | 2 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 0.5% | [0.3%, 0.7%] | 2 | Likely due to [#142641](https://github.com/rust-lang/rust/pull/142641) which added extra work to proc-macro crates, which are the benchmarks affected here. #### Improvements Encode hir attributes cross-crate properly [#142777](https://github.com/rust-lang/rust/pull/142777) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d14d202262d13df896b0c624b0cec6e4bfde631a&end=0fa4ec6cde46fa17ab07acb5531cfe0dc1349ffa&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.4% | [-1.4%, -0.1%] | 16 | | Improvements (secondary) | -0.6% | [-1.3%, -0.2%] | 20 | | All (primary) | -0.4% | [-1.4%, -0.1%] | 16 | Rollup of 8 pull requests [#143057](https://github.com/rust-lang/rust/pull/143057) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=b03b3a7ec92682be2917540b679478d41c95a30c&end=513999b936c37902120380f4171963d1f1d80347&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.4% | [-0.4%, -0.3%] | 3 | | Improvements (secondary) | - | - | 0 | | All (primary) | -0.4% | [-0.4%, -0.3%] | 3 | Fast path for WF goals in new solver [#142223](https://github.com/rust-lang/rust/pull/142223) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=e61dd437f33b5a640e67dc3628397689c664c17f&end=df32e15c56f582eb2bdde07711af6271f2ae660b&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.2% | [-0.4%, -0.1%] | 8 | | Improvements (secondary) | -1.5% | [-3.5%, -0.3%] | 13 | | All (primary) | -0.2% | [-0.4%, -0.1%] | 8 | Collapse Analysis|Borrowck|PostBorrowckAnalysis when there are no opaques [#142802](https://github.com/rust-lang/rust/pull/142802) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=ed2d759783dc9de134bbb3f01085b1e6dbf539f3&end=35f6036521777bdc0dcea1f980be4c192962a168&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.2% | [0.1%, 0.2%] | 2 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -2.4% | [-7.5%, -0.5%] | 14 | | All (primary) | - | - | 0 | Shallowly bail from `coerce_unsized` more [#142941](https://github.com/rust-lang/rust/pull/142941) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=35f6036521777bdc0dcea1f980be4c192962a168&end=f19142044f270760ce0ebc03b2c3a44217d8703d&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:---------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.8% | [0.8%, 0.8%] | 1 | | Improvements (primary) | -0.8% | [-4.6%, -0.2%] | 84 | | Improvements (secondary) | -5.6% | [-21.6%, -0.1%] | 71 | | All (primary) | -0.8% | [-4.6%, -0.2%] | 84 | #### Mixed update to literal-escaper 0.0.4 for better API without `unreachable` and faster string parsing [#140999](https://github.com/rust-lang/rust/pull/140999) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=3de5b08ef6b260277dd4c77f7472fe6904bd6002&end=2c2bb995af398383e3b93b859302bdc447ca7a7c&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.2% | [0.2%, 0.3%] | 3 | | Regressions (secondary) | 0.3% | [0.3%, 0.3%] | 1 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -0.7% | [-1.2%, -0.4%] | 16 | | All (primary) | 0.2% | [0.2%, 0.3%] | 3 | Regressions limited to stm32f4, some mild improvements, doesn't seem worth further investigation. Stop collecting unmentioned constants [#142893](https://github.com/rust-lang/rust/pull/142893) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=d51b6f97122671c5de27cfc08cded235357e0d97&end=13c46fd0b089360922a557d8e18a63a2c41dfbeb&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:------:|:----------------:|:-----:| | Regressions (primary) | 19.2% | [17.2%, 21.2%] | 2 | | Regressions (secondary) | 9.1% | [6.0%, 13.4%] | 5 | | Improvements (primary) | -1.6% | [-2.3%, -0.8%] | 8 | | Improvements (secondary) | -67.8% | [-67.9%, -67.8%] | 2 | | All (primary) | 2.6% | [-2.3%, 21.2%] | 10 | Regressed benchmarks are incremental scenarios which have changed codegen units -- overall, this is an improvement in the typical case. Don't fold in Instantiate when there's nothing to fold [#142317](https://github.com/rust-lang/rust/pull/142317) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=b63223c152212832ce37a109e26cc5f84c577532&end=7ba34c704529e7fcab80130c3fe40efe415d61b5&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.2% | [0.1%, 0.3%] | 9 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.2% | [-0.3%, -0.1%] | 3 | | Improvements (secondary) | -2.6% | [-2.9%, -2.4%] | 6 | | All (primary) | 0.1% | [-0.3%, 0.3%] | 12 | Some mixed results from this but improvements were deemed as outweighing the regressions ([comment](https://github.com/rust-lang/rust/pull/142317#issuecomment-2964689882)). Only compute recursive callees once. [#142625](https://github.com/rust-lang/rust/pull/142625) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=7ba34c704529e7fcab80130c3fe40efe415d61b5&end=11ad40bb839ca16f74784b4ab72596ad85587298&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.4% | [0.3%, 0.6%] | 3 | | Regressions (secondary) | 0.3% | [0.3%, 0.3%] | 2 | | Improvements (primary) | -1.3% | [-2.5%, -0.2%] | 2 | | Improvements (secondary) | - | - | 0 | | All (primary) | -0.3% | [-2.5%, 0.6%] | 5 | Per the PR description makes some intentional tradeoffs between two variants of implementation and is overall an improvement or neutral. Stop backends from needing to support nullary intrinsics [#142839](https://github.com/rust-lang/rust/pull/142839) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f19142044f270760ce0ebc03b2c3a44217d8703d&end=ad3b7257615c28aaf8212a189ec032b8af75de51&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 2.7% | [2.7%, 2.7%] | 1 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.3% | [-0.4%, -0.3%] | 5 | | Improvements (secondary) | - | - | 0 | | All (primary) | 0.2% | [-0.4%, 2.7%] | 6 | Some slight changes, no particularly significant changes. ## Nominated Issues [T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-compiler-nominated) - No I-compiler-nominated issues this time. [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) - "[Coverage][MCDC] Do not initialize mcdc parameters for instances containing no mcdc statements" [rust#129989](https://github.com/rust-lang/rust/pull/129989) (last review activity: 3 months ago) - Assigned reviewer @**Zalathar** last expressed concerns about the PR - I wonder if we should discuss this, there is a tracking issue for [MCDC coverage](https://github.com/rust-lang/rust/issues/124144) - "Do not eagerly reject inference vars when trying to resolve method calls." [rust#126316](https://github.com/rust-lang/rust/pull/126316) (last review activity: 2 months ago) - cc @**lcnr** (just reminder, but it's something to work with Oli) - "Do not run per-module late lints if they can be all skipped" [rust#139597](https://github.com/rust-lang/rust/pull/139597) (last review activity: 2 months ago) - cc: @**Boxy** - "Suppress suggestions while span is in external library" [rust#139316](https://github.com/rust-lang/rust/pull/139316) (last review activity: 2 months ago) - unsure about this one, seems it needs some design first ([comment](https://github.com/rust-lang/rust/pull/139316#pullrequestreview-2809567076)) - "Don't lint against named labels in `naked_asm!`" [rust#140871](https://github.com/rust-lang/rust/pull/140871) (last review activity: about 53 days ago) - cc @**Michael (compiler-errors) Goulet** Next meetings' agenda draft: [hackmd link](https://hackmd.io/XCRrBw9CTCyurvEHtb7WnQ)

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