--- # System prepended metadata title: T-compiler Meeting Agenda 2026-03-26 tags: [' rustc', weekly] --- --- tags: weekly, rustc type: docs note_id: -cLp7QNdRx6ortU7xb3XWw --- # T-compiler Meeting Agenda 2026-03-26 ## Announcements - Today, patch release 1.94.1, see [blog post](https://github.com/Mark-Simulacrum/blog.rust-lang.org/blob/release-blog/content/1.94.1-release.md) (patches are not for the compiler) - FYI from @_**jieyouxu**: WG-linker is now an active WG :) Zulip group is @_*WG-linker* (see https://github.com/rust-lang/team/pull/2299) - 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). ## MCPs/FCPs - New MCPs (take a look, see if you like them!) - No new proposals this time. - Old MCPs (stale MCP might be closed as per [MCP procedure](https://forge.rust-lang.org/compiler/mcp.html#when-should-major-change-proposals-be-closed)) - None at this time - Old MCPs (not seconded, take a look) - "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 0 days 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: 5 months ago) - concern: [wont-stop-target-names-from-proliferating](https://github.com/rust-lang/compiler-team/issues/850#issuecomment-3074434152) - "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: 8 months ago) - concern: [proposal-wording](https://github.com/rust-lang/compiler-team/issues/876#issuecomment-3078140906) - "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: 8 months ago) - "Split the `-openbsd*` targets by version" [compiler-team#916](https://github.com/rust-lang/compiler-team/issues/916) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Split.20the.20.60-openbsd.2A.60.20targets.20by.20version.20compiler-team.23916)) (last review activity: 5 months ago) - concern: [why-not-ports-rustc](https://github.com/rust-lang/compiler-team/issues/916#issuecomment-3315251054) - concern: [nonsystematic-breakage](https://github.com/rust-lang/compiler-team/issues/916#issuecomment-3315243666) - concern: [version-churn](https://github.com/rust-lang/compiler-team/issues/916#issuecomment-3315239793) - "Stop bumping the bootstrap version on every rustc release" [compiler-team#925](https://github.com/rust-lang/compiler-team/issues/925) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Stop.20bumping.20the.20bootstrap.20version.20on.20eve.E2.80.A6.20compiler-team.23925)) (last review activity: about 40 days ago) - concern: [we-like-using-the-features-we-ship](https://github.com/rust-lang/compiler-team/issues/925#issuecomment-3898616402) - concern: [infra-and-bootstrap-burden](https://github.com/rust-lang/compiler-team/issues/925#issuecomment-3898603216) - "Doc comments and attributes on macro arms" [compiler-team#935](https://github.com/rust-lang/compiler-team/issues/935) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Doc.20comments.20and.20attributes.20on.20macro.20arms.20compiler-team.23935)) (last review activity: 4 months ago) - concern: [lang](https://github.com/rust-lang/compiler-team/issues/935#issuecomment-3444181159) - "Publish `rustc_public` crate v0.1 to crates.io" [compiler-team#949](https://github.com/rust-lang/compiler-team/issues/949) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Publish.20.60rustc_public.60.20crate.20v0.2E1.20to.20crat.E2.80.A6.20compiler-team.23949)) (last review activity: about 3 days ago) - concern: [ease of refreshing in tree rustc_public to match actual rustc](https://github.com/rust-lang/compiler-team/issues/949#issuecomment-4106240317) - concern: [clarify blocking/non-blocking nature of librarification project reviews](https://github.com/rust-lang/compiler-team/issues/949#issuecomment-4106239976) - "Add flag to pass MSRV/`package.rust-version` for use by lints" [compiler-team#950](https://github.com/rust-lang/compiler-team/issues/950) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20.60-Z.20msrv.3Dxx.2Eyy.2Ezz.60.20flag.20compiler-team.23950)) (last review activity: about 55 days ago) - "Create a new Tier 3 target: ` x86_64-nt-windows-msvc`" [compiler-team#952](https://github.com/rust-lang/compiler-team/issues/952) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Create.20a.20new.20Tier.203.20target.3A.20.60.20x86_64-nt-w.E2.80.A6.20compiler-team.23952)) (last review activity: about 55 days ago) - "Query `git` state to get information on a currently ongoing rebase when encountering conflict markers" [compiler-team#955](https://github.com/rust-lang/compiler-team/issues/955) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Query.20.60git.60.20state.20to.20get.20information.20on.20a.E2.80.A6.20compiler-team.23955)) (last review activity: about 55 days ago) - concern: [not worth the complexity](https://github.com/rust-lang/compiler-team/issues/955#issuecomment-3684138445) - "Add repro-check tool for build reproducibility" [compiler-team#962](https://github.com/rust-lang/compiler-team/issues/962) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20repro-check.20tool.20for.20build.20reproducib.E2.80.A6.20compiler-team.23962)) (last review activity: about 55 days ago) - "Allow crates downstream of `rustc_middle` to define queries" [compiler-team#966](https://github.com/rust-lang/compiler-team/issues/966) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Allow.20crates.20downstream.20of.20.60rustc_middle.60.E2.80.A6.20compiler-team.23966)) (last review activity: about 41 days ago) - concern: [complexity](https://github.com/rust-lang/compiler-team/issues/966#issuecomment-3863771183) - concern: [fragmentation](https://github.com/rust-lang/compiler-team/issues/966#issuecomment-3863853297) - "Add -Z dead-fn-elimination to skip codegen of BFS-unreachable functions" [compiler-team#976](https://github.com/rust-lang/compiler-team/issues/976) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20-Z.20dead-fn-elimination.20to.20skip.20codege.E2.80.A6.20compiler-team.23976)) (last review activity: about 2 days ago) - "Change the ABI of powerpc64-unknown-linux-gnu to ELFv2" [compiler-team#977](https://github.com/rust-lang/compiler-team/issues/977) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Change.20the.20ABI.20of.20powerpc64-unknown-linux.E2.80.A6.20compiler-team.23977)) (last review activity: about 6 days ago) - Pending FCP requests (check your boxes!) - merge: [Promote loongarch32-unknown-none* to Tier 2 (compiler-team#968)](https://github.com/rust-lang/compiler-team/issues/968#issuecomment-3907992097) - @_**|124288** @_**|125250** @_**|119031** @_**|353056** - no pending concerns - 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: [Make trait refs & assoc ty paths properly induce trait object lifetime defaults (rust#129543)](https://github.com/rust-lang/rust/pull/129543#issuecomment-2862410551) - @_**|116009** @_**|326176** @_**|216206** @_**|232957** - no pending concerns - merge: [Stabilize stack-protector (rust#146369)](https://github.com/rust-lang/rust/pull/146369#issuecomment-3271397169) - @_**|116266** @_**|426609** @_**|444933** - concerns: [mitigation-enforcement (by Noratrieb)](https://github.com/rust-lang/rust/pull/146369#issuecomment-3286402251) - merge: [Stabilize the `supertrait_item_shadowing` feature (rust#148605)](https://github.com/rust-lang/rust/pull/148605#issuecomment-3582962396) - @_**|124288** @_**|326176** - concerns: [implementation-confidence (by BoxyUwU)](https://github.com/rust-lang/rust/pull/148605#issuecomment-3853046997) [inconsistent-name-res-semantics (by BoxyUwU)](https://github.com/rust-lang/rust/pull/148605#issuecomment-3853051038) - "Implement lint for black_boxing ZSTs" [rust#150037](https://github.com/rust-lang/rust/pull/150037) - merge: [WF checks on closure arguments. (rust#151510)](https://github.com/rust-lang/rust/pull/151510#issuecomment-3996248181) - @_**|124288** @_**|326176** @_**|232957** - concerns: [jobsteal crater regression fix (by lcnr)](https://github.com/rust-lang/rust/pull/151510#issuecomment-3996255213) - merge: [Clean up crate type names to fix dylib vs staticlib confusion (rust#153863)](https://github.com/rust-lang/rust/issues/153863#issuecomment-4061709608) - @_**|120518** @_**|116266** @_**|424212** @_**|124288** @_**|270929** @_**|125250** @_**|116107** @_**|248906** @_**|120179** @_**|245964** @_**|116118** @_**|415544** @_**|296292** @_**|353056** - concerns: [cargo-impact (by epage)](https://github.com/rust-lang/rust/issues/153863#issuecomment-4070064048) - 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: [impl-at-mir-level](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: [lose-debuginfo-data](https://github.com/rust-lang/compiler-team/issues/841#issuecomment-2683562830) - "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)) - concern: [continued-maintainer-interest](https://github.com/rust-lang/compiler-team/issues/864#issuecomment-3535030586) - concern: [documentation](https://github.com/rust-lang/compiler-team/issues/864#issuecomment-3535045453) - "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) - "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)) - "Emit retags in codegen" [compiler-team#958](https://github.com/rust-lang/compiler-team/issues/958) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Emit.20retags.20in.20codegen.20compiler-team.23958)) - "Syntactically reject equality predicates" [rust#153513](https://github.com/rust-lang/rust/pull/153513) - "1.95 beta regression: "malformed `feature` attribute input"" [rust#153764](https://github.com/rust-lang/rust/issues/153764) - "stabilize s390x vector registers" [rust#154184](https://github.com/rust-lang/rust/pull/154184) - Accepted MCPs - "Tier 3 targets proposal: LoongArch UEFI" [compiler-team#953](https://github.com/rust-lang/compiler-team/issues/953) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Tier.203.20targets.20proposal.3A.20LoongArch.20UEFI.20compiler-team.23953)) - "Remove -Csoft-float" [compiler-team#971](https://github.com/rust-lang/compiler-team/issues/971) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Remove.20-Csoft-float.20compiler-team.23971)) - "allow `incomplete_features` in UI tests" [compiler-team#974](https://github.com/rust-lang/compiler-team/issues/974) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/allow.20.60incomplete_features.60.20in.20UI.20tests.20compiler-team.23974)) - "Add `-Zsanitizer=kernel-hwaddress`" [compiler-team#975](https://github.com/rust-lang/compiler-team/issues/975) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20.60-Zsanitizer.3Dkernel-hwaddress.60.20compiler-team.23975)) - Finalized FCPs (disposition merge) - "rustc: Stop passing `--allow-undefined` on wasm targets" [rust#149868](https://github.com/rust-lang/rust/pull/149868) - "switch to v0 mangling by default on stable" [rust#151994](https://github.com/rust-lang/rust/pull/151994) - Other teams finalized FCPs - [T-types] "Always make tuple elements a coercion site" [rust#147834](https://github.com/rust-lang/rust/pull/147834) - [T-rustdoc, T-lang] "Stabilize Frontmatter" [rust#148051](https://github.com/rust-lang/rust/pull/148051) - [T-types] "Always check `ConstArgHasType` even when otherwise ignoring" [rust#152931](https://github.com/rust-lang/rust/pull/152931) ## 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: "[beta] Revert #151380 in beta" [rust#154307](https://github.com/rust-lang/rust/pull/154307) - Authored by ShoyuVanilla - Fixes #153816 and #153849. The fix has two parts: - #154307 (this backport): reverts #151380 on beta - #154308: reverts on nightly #151380 and #153869 - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23154307.3A.20beta-nominated/near/581415691), in favor - :beta: "Init `self_decl` with a correct visibility" [rust#154313](https://github.com/rust-lang/rust/pull/154313) - Authored by mu001999 - Fixes #154295, code compiles that should not be accepted (debug builds only) - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23154313.3A.20beta-nominated/near/581651652), in favor - :beta: "Update LLVM to 22.1.2" [rust#154344](https://github.com/rust-lang/rust/pull/154344) - Authored by dianqk - From ([comment](https://github.com/rust-lang/rust/pull/154344#issuecomment-4124882573)): > Fixes a not so important nightly-only miscompile for the s390x `f16::is_normal` miscompile > BUT fixes quite a few long-standing LLVM 22 issues (at least a ppc64le miscompile affecting the Rust uuid crate, a crash when building with PGO, and a build hang on s390x) - [List of changes](https://github.com/rust-lang/llvm-project/compare/41f177ed26a5252a30ea6090a4da66ce0a96bf44...05918363362b439b9b0bced3daa14badd75da790) - Voting [Zulip topic](https://rust-lang.zulipchat.com/#narrow/channel/474880-t-compiler.2Fbackports/topic/.23154344.3A.20beta-nominated/near/581557110), in favor - No stable nominations for `T-compiler` this time. [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-t-compiler [T-compiler](https://github.com/rust-lang/rust/pulls?q=is%3Aopen+label%3AS-waiting-on-t-compiler) - "Strict version hash is sensitive to presence of standard library source code on host" [rust#153898](https://github.com/rust-lang/rust/issues/153898) - Question: do we provide any stability guarantees for these hashes? - [Issues in progress or waiting on other teams](https://hackmd.io/XYr1BrOWSiqCrl8RCWXRaQ) ## Issues of Note ### Short Summary - [1 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) - [62 T-compiler P-high issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high) - [46 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, 2 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, 0 P-low regression-from-stable-to-nightly](https://github.com/rust-lang/rust/labels/regression-from-stable-to-nightly) - [0 P-critical, 35 P-high, 100 P-medium, 31 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) - None [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) - "Significant compilation time regression starting in v1.95.0-nightly (bevy)" [rust#153910](https://github.com/rust-lang/rust/issues/153910) - Still need investigation. A reduction would be useful (the bevy crate pulls in a lot of deps) - "Complex EH flow miscompiled on wasm" [rust#153948](https://github.com/rust-lang/rust/issues/153948) - Investigated by @_**Hood Chatham** ([comment](https://github.com/rust-lang/rust/issues/153948#issuecomment-4089579826)), opened an upstream issue [llvm-project#187302](https://github.com/llvm/llvm-project/issues/187302). Note: affects only legacy `eh`, the codegen with`-wasm-use-legacy-eh=false` is correct. - asks if in the meanwhile shouldn't we revert #151771 (from @_**apiraino**: I would be in favor of reverting, seems quite self-contained) [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-bootstrap) - No unassigned `P-high` nightly regressions this time. ## Performance logs > [2026-03-24 Triage Log](https://github.com/rust-lang/rustc-perf/tree/master/triage/2026) Lot of mixed results this week. One big regression from [#152931](https://github.com/rust-lang/rust/pull/152931) makes the results look pretty negative, but otherwise the week was fairly quiet. Triage done by **@panstromek**. Revision range: [5b61449e..6f22f613](https://perf.rust-lang.org/?start=5b61449ed85a670f1dd3fca6a8c759ee0b451b66&end=6f22f61305478df09f9a4523743f85d9f558c3d7&absolute=false&stat=instructions%3Au) **Summary**: | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 1.0% | [0.1%, 4.2%] | 27 | | Regressions (secondary) | 0.2% | [0.0%, 0.6%] | 36 | | Improvements (primary) | -0.1% | [-0.2%, -0.1%] | 3 | | Improvements (secondary) | -0.3% | [-2.8%, -0.0%] | 14 | | All (primary) | 0.9% | [-0.2%, 4.2%] | 30 | 1 Regression, 1 Improvement, 4 Mixed; 1 of them in rollups 32 artifact comparisons made in total #### Regressions Always check `ConstArgHasType` even when otherwise ignoring [#152931](https://github.com/rust-lang/rust/pull/152931) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=eb9d3caf0511a5fa9fa70251e2ac9fa33a9a4652&end=f66622c7eca7fc48ccc4dac848ff911b09a4d566&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:----:|:------------:|:-----:| | Regressions (primary) | 1.9% | [0.1%, 4.1%] | 13 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | - | - | 0 | | All (primary) | 1.9% | [0.1%, 4.1%] | 13 | These regressions look real, and it seems like they were not discussed before merge. Regressed benchmarks are both type-heavy, and the regression seems to be entirely in typeck (`assumed_wf_types`, `check_well_formed`, `predicates_of` and `type_alias_is_lazy` all show some negative changes in detailed results). This seems to match the PR changes. Asked on the PR, got response from reviewer: "typenum has a lot of type aliases, so doing additional work for them causing a regression seems expected to me. Looking at the code, I don't know how to avoid this regression" #### Improvements `DepNode` use improvements [#154076](https://github.com/rust-lang/rust/pull/154076) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=6f22f61305478df09f9a4523743f85d9f558c3d7&end=212b0d480f337082bbe1132d2b62be20e7e61f8a&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -0.2% | [-0.3%, -0.0%] | 12 | | All (primary) | - | - | 0 | #### Mixed Do not shallow resolve to root var while fudging [#153869](https://github.com/rust-lang/rust/pull/153869) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=8b86f48958be8c3473c979e0b5504c2d2e0fd4fd&end=1f7f8ea0721a3b1eb73e6c6d25cccb371434b320&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.3% | [0.2%, 0.4%] | 7 | | Improvements (primary) | -0.1% | [-0.1%, -0.1%] | 2 | | Improvements (secondary) | -0.3% | [-0.3%, -0.2%] | 4 | | All (primary) | -0.1% | [-0.1%, -0.1%] | 2 | Improvements mostly outweigh regressions. Secondary regressions in `projection-caching` and `regression-31157` seem to just undo part of the wins from https://github.com/rust-lang/rust/pull/151380, so this still seems like a net improvement overall. Eagerly normalize in generalize [#151746](https://github.com/rust-lang/rust/pull/151746) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=bfc05d6b072585dfd0c792ec1b8728c08a3511fe&end=ac7f9ec7da74d37fd28667c86bf117a39ba5b02a&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.2% | [0.2%, 0.3%] | 7 | | Regressions (secondary) | 0.3% | [0.1%, 0.4%] | 10 | | Improvements (primary) | - | - | 0 | | Improvements (secondary) | -0.4% | [-0.4%, -0.4%] | 1 | | All (primary) | 0.2% | [0.2%, 0.3%] | 7 | Reverted in https://github.com/rust-lang/rust/pull/154257 for other reasons Remove the `anon` query modifier [#154122](https://github.com/rust-lang/rust/pull/154122) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=20f19f4615200b16e3631816e7824e832ff394db&end=562dee4820c458d823175268e41601d4c060588a&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | 0.3% | [0.2%, 0.3%] | 3 | | Regressions (secondary) | - | - | 0 | | Improvements (primary) | -0.2% | [-0.2%, -0.2%] | 2 | | Improvements (secondary) | -0.1% | [-0.2%, -0.1%] | 2 | | All (primary) | 0.1% | [-0.2%, 0.3%] | 5 | Quoting the author (@Zalathar): "Small regressions to `cargo` were expected, and everything else is green. I'm experimenting with [#154162](https://github.com/rust-lang/rust/pull/154162) to undo those small regressions, but that work will have to be judged on its own perf/complexity merits." Rollup of 8 pull requests [#154273](https://github.com/rust-lang/rust/pull/154273) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=f66622c7eca7fc48ccc4dac848ff911b09a4d566&end=6f22f61305478df09f9a4523743f85d9f558c3d7&stat=instructions:u) | (instructions:u) | mean | range | count | |:------------------------:|:-----:|:--------------:|:-----:| | Regressions (primary) | - | - | 0 | | Regressions (secondary) | 0.4% | [0.4%, 0.4%] | 1 | | Improvements (primary) | -0.2% | [-0.3%, -0.1%] | 7 | | Improvements (secondary) | -0.2% | [-0.4%, -0.1%] | 17 | | All (primary) | -0.2% | [-0.3%, -0.1%] | 7 | Regressions are noise, already triaged by @JonathanBrouwer ## Nominated Issues [T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-compiler-nominated) - None ### Open T-compiler RFCs with disposition-merge + finished FCP List: https://github.com/rust-lang/rfcs/issues?q=sort%3Aupdated-desc%20state%3Aopen%20label%3Afinished-final-comment-period%20label%3Adisposition-merge From @_**jieyouxu**: I saw a IRLO thread recently regarding "FCP complete but not merged RFCs" so I was curious how we are doing. I only see two of them: - "Mitigation enforcement" [rfcs#3855](https://github.com/rust-lang/rfcs/pull/3855) - Finished FCP 2 weeks ago: https://github.com/rust-lang/rfcs/pull/3855#issuecomment-4050365833 - AFAICT this one seems okay to merge, I don't see any notable outstanding comments/concerns - Comment from @_**apiraino**: I think I agree, also [rust#146369](https://github.com/rust-lang/rust/pull/146369) was waiting on this (see [comment](https://github.com/rust-lang/rust/pull/146369#issuecomment-3288755608)) - "[RFC2603] Extend `` to include str and structural constants" [rfcs#3161](https://github.com/rust-lang/rfcs/pull/3161) - Finished FCP in 2023: https://github.com/rust-lang/rfcs/pull/3161#issuecomment-1727997539 - Now this RFC I think is maybe not ready for merge: outstanding concerns / notable unresolved questions: - There was some weak concern re. documenting unstable features at the time of FCP: https://github.com/rust-lang/rfcs/pull/3161#issuecomment-1930532909 - https://github.com/rust-lang/rfcs/pull/3161#issuecomment-2180425897 - https://github.com/rust-lang/rfcs/pull/3161#issuecomment-2191837103 - *Maybe* @_*project-const-traits* have some further feedback for the discussions? - EDIT: oh, this is an **amendment** to an existing RFC. Then I'd say I agree with Eric's comment where > Process-wise, instead of amending RFCs, this should probably be done as a PR to update the documentation at rust-lang/rust@master/src/doc/rustc/src/symbol-mangling/v0.md. - Comment from @_**apiraino**: isn't the mangling v0 in FCP now? See: - "switch to v0 mangling by default on stable" [rust#151994](https://github.com/rust-lang/rust/pull/151994) - Very old story, I'd probably leave a ping there and ask about the status [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) - "Store `chunk_domain_size` explicitly in `Chunk`." [rust#147802](https://github.com/rust-lang/rust/pull/147802) (last review activity: 5 months ago) - cc @**cjgillot** Next meetings' agenda draft: [hackmd link](https://hackmd.io/qk6pLRaLSS2_MnVFtHUGqQ)