T-compiler Meeting Agenda 2024-09-05

--- tags: weekly, rustc type: docs note_id: 68SAwhUVRmC5oPTrsheiBg --- # T-compiler Meeting Agenda 2024-09-05 ## Announcements - Today Rust stable release 1.81. [Blog post](https://github.com/rust-lang/blog.rust-lang.org/blob/d6462701b5bba2581eba936fa0d322cfe8157a3f/posts/2024-09-05-Rust-1.81.0.md) - Draft blog post for the election of the Project Directors (PDs): https://github.com/rust-lang/blog.rust-lang.org/blob/fb8299d3dd4d42eb928442115a8a730889c466bb/posts/inside-rust/2024-09-04-electing-new-project-directors.md - Draft blog post about upcoming changes in WASM targets : https://github.com/rust-lang/blog.rust-lang.org/pull/1385 - Context: https://github.com/rust-lang/rust/pull/128511 - after a cursory review from t-compiler (thanks!), we can set a date for publishing - 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 - Types Team: ITE (Impl Trait Everywhere) Triage <time:2024-09-05T22:00:00+01:00> - wg-rust-analyzer steering meeting on Zulip (https://rust-lang.zulipchat.com/#narrow/stream/185405-t-compiler.2Fwg-rls-2.2E0/topic/Steering.20meeting) <time:2024-09-06T17:00:00+01:00> - wg-macros triage meeting Zulip (https://rust-lang.zulipchat.com/#narrow/stream/410876-wg-macros.2Ftriage) <time:2024-09-06T18:00:00+01:00> ## MCPs/FCPs - New MCPs (take a look, see if you like them!) - "Add `evex512` target feature for AVX10" [compiler-team#778](https://github.com/rust-lang/compiler-team/issues/778) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20.60evex512.60.20target.20feature.20for.20AVX10.20compiler-team.23778)) - "mark some target features as 'forbidden' so they cannot be (un)set with -Ctarget-feature" [compiler-team#780](https://github.com/rust-lang/compiler-team/issues/780) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/mark.20some.20target.20features.20as.20.27forbidden.27.20.E2.80.A6.20compiler-team.23780)) - 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) - "Target families for executable format" [compiler-team#716](https://github.com/rust-lang/compiler-team/issues/716) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Target.20families.20for.20executable.20format.20compiler-team.23716)) (last review activity: 7 months ago) - "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: 3 months ago) - "Opt-in flag for absolute paths in diagnostics" [compiler-team#770](https://github.com/rust-lang/compiler-team/issues/770) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Opt-in.20flag.20for.20absolute.20paths.20in.20diagnos.E2.80.A6.20compiler-team.23770)) (last review activity: about 20 days ago) - Pending FCP requests (check your boxes!) - "sanitizers: Stabilize AddressSanitizer and LeakSanitizer for the Tier 1 targets" [rust#123617](https://github.com/rust-lang/rust/pull/123617) - "Add `--print host-triple` to print host target triple" [rust#125579](https://github.com/rust-lang/rust/pull/125579) - Things in FCP (make sure you're good with it) - "Don't track `--emit=` options as part of crate SVH" [compiler-team#769](https://github.com/rust-lang/compiler-team/issues/769) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Don.27t.20track.20.60--emit.3D.60.20options.20as.20part.20of.20.E2.80.A6.20compiler-team.23769)) - "`--hint-msrv=version` option so the compiler can take MSRV into account when linting" [compiler-team#772](https://github.com/rust-lang/compiler-team/issues/772) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/.60-C.20msrv.3Dversion.60.20option.20so.20the.20compiler.20.E2.80.A6.20compiler-team.23772)) - "Deprecate `-Csoft-float`" [compiler-team#779](https://github.com/rust-lang/compiler-team/issues/779) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Deprecate.20.60-Csoft-float.60.20compiler-team.23779)) - "const-eval interning: accept interior mutable pointers in final value" [rust#128543](https://github.com/rust-lang/rust/pull/128543) - "Don't warn empty branches unreachable for now" [rust#129103](https://github.com/rust-lang/rust/pull/129103) - Accepted MCPs - No new accepted proposals this time. - 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: 7 months ago) - concern: [added-complexity-to-frontend](https://github.com/rust-lang/compiler-team/issues/692#issuecomment-1845169318) - "Add a new `--build-id` flag to rustc" [compiler-team#635](https://github.com/rust-lang/compiler-team/issues/635) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Add.20a.20new.20.60--build-id.60.20flag.20to.20rustc.20compiler-team.23635)) - concern: [other-existing-options](https://github.com/rust-lang/compiler-team/issues/635#issuecomment-1779597156) - concern: [option-name](https://github.com/rust-lang/compiler-team/issues/635#issuecomment-1785349936) - "Retire the mailing list and make all decisions on zulip" [compiler-team#649](https://github.com/rust-lang/compiler-team/issues/649) ([Zulip](https://rust-lang.zulipchat.com/#narrow/stream/233931-xxx/topic/Retire.20the.20mailing.20list.20and.20make.20all.20deci.E2.80.A6.20compiler-team.23649)) - concern: [automatic-sync](https://github.com/rust-lang/compiler-team/issues/649#issuecomment-1618902660) - Finalized FCPs (disposition merge) - None - Other teams finalized FCPs - "rustdoc: add header map to the table of contents" [rust#120736](https://github.com/rust-lang/rust/pull/120736) - "doc: Make block of inline Deref methods foldable" [rust#127474](https://github.com/rust-lang/rust/pull/127474) ### WG checkins None ## Backport nominations [T-compiler beta](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-compiler) / [T-compiler stable](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Astable-nominated+-label%3Astable-accepted+label%3AT-compiler) - No beta nominations for `T-compiler` this time. - No stable nominations for `T-compiler` this time. [T-types stable](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-types) / [T-types beta](https://github.com/rust-lang/rust/issues?q=is%3Aall+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) - "Stabilize `extended_varargs_abi_support`" [rust#116161](https://github.com/rust-lang/rust/pull/116161) - "Better errors with bad/missing identifiers in MBEs" [rust#118939](https://github.com/rust-lang/rust/pull/118939) - "Uplift `clippy::invalid_null_ptr_usage` lint" [rust#119220](https://github.com/rust-lang/rust/pull/119220) - "Rename `AsyncIterator` back to `Stream`, introduce an AFIT-based `AsyncIterator` trait" [rust#119550](https://github.com/rust-lang/rust/pull/119550) - "Disallow deriving (other than Copy/Clone) on types with unnamed fields" [rust#121270](https://github.com/rust-lang/rust/pull/121270) - "Emit a warning if a `match` is too complex" [rust#122685](https://github.com/rust-lang/rust/pull/122685) - "Add Unicode block-drawing compiler output support" [rust#126597](https://github.com/rust-lang/rust/pull/126597) - "Emit error when calling/declaring functions with vectors that require missing target feature" [rust#127731](https://github.com/rust-lang/rust/pull/127731) - "[crater] Make `missing_fragment_specifier` an unconditional error" [rust#128425](https://github.com/rust-lang/rust/pull/128425) - "repr(int) fieldless enums are ABI-compatible with int" [rust#128600](https://github.com/rust-lang/rust/pull/128600) - "`optimize` attribute applied to things other than methods/functions/c…" [rust#128943](https://github.com/rust-lang/rust/pull/128943) - "Gate `repr(Rust)` correctly on non-ADT items" [rust#129422](https://github.com/rust-lang/rust/pull/129422) - [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) - [66 T-compiler P-high issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high) - [38 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, 1 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, 5 P-medium, 2 P-low regression-from-stable-to-nightly](https://github.com/rust-lang/rust/labels/regression-from-stable-to-nightly) - [0 P-critical, 36 P-high, 100 P-medium, 16 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+-label%3AT-core) - [SIGTRAP during compilation on MacOS · Issue #129887 · rust-lang/rust](https://github.com/rust-lang/rust/issues/129887) - issue just slipped from nightly to beta. Already fixed upstream in LLVM 19 ([comment](https://github.com/rust-lang/rust/issues/129887#issuecomment-2330461075)) - "regression: overflow evaluating the requirement" [rust#128887](https://github.com/rust-lang/rust/issues/128887) - accepted regression, some crates that regressed fixed downstream. - fixed by #129714 (beta backported) and #129073 (in progress), thus keeping it open for tracking purposes [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 2024-09-03](https://github.com/Kobzol/rustc-perf/blob/ee7cd7e680ebf9d588ad23cc0f1ba32b3caf1813/triage/2024-09-03.md) This week we had some trouble with our performance bot, but luckily the issue has been resolved. In the end, we saw much more improvements than regressions. Triage done by **@kobzol**. Revision range: [acb4e8b6..6199b69c](https://perf.rust-lang.org/?start=acb4e8b6251f1d8da36f08e7a70fa23fc581839e&end=6199b69c53a8c275ca3cd59647ea0af5ca29aae2&absolute=false&stat=instructions%3Au) **Summary**: | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions ❌ (primary) | 0.3% | [0.2%, 0.4%] | 8 | | Regressions ❌ (secondary) | 0.7% | [0.2%, 1.5%] | 9 | | Improvements ✅ (primary) | -0.8% | [-3.4%, -0.2%] | 158 | | Improvements ✅ (secondary) | -0.7% | [-2.3%, -0.2%] | 96 | | All ❌✅ (primary) | -0.7% | [-3.4%, 0.4%] | 166 | 2 Regressions, 3 Improvements, 1 Mixed; 3 of them in rollups 19 artifact comparisons made in total #### Regressions Rollup of 7 pull requests [#129750](https://github.com/rust-lang/rust/pull/129750) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=784d444733d65c3d305ce5edcbb41e3d0d0aee2e&end=0d634185dfddefe09047881175f35c65d68dcff1&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:----:|:------------:|:-----:| | Regressions ❌ (primary) | 0.4% | [0.3%, 0.5%] | 7 | | Regressions ❌ (secondary) | 6.0% | [6.0%, 6.0%] | 1 | | Improvements ✅ (primary) | - | - | 0 | | Improvements ✅ (secondary) | - | - | 0 | | All ❌✅ (primary) | 0.4% | [0.3%, 0.5%] | 7 | - This was bimodal noise. Rollup of 8 pull requests [#129922](https://github.com/rust-lang/rust/pull/129922) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=6199b69c53a8c275ca3cd59647ea0af5ca29aae2&end=d6c8169c186ab16a3404cd0d0866674018e8a19e&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:----:|:------------:|:-----:| | Regressions ❌ (primary) | - | - | 0 | | Regressions ❌ (secondary) | 5.8% | [5.8%, 5.8%] | 1 | | Improvements ✅ (primary) | - | - | 0 | | Improvements ✅ (secondary) | - | - | 0 | | All ❌✅ (primary) | - | - | 0 | - Likely the same story, just with a different benchmark. - Not marking as triaged yet. #### Improvements Rollup of 15 pull requests [#129809](https://github.com/rust-lang/rust/pull/129809) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=fa72f0763de6bc1596208fc1419883ce5aea0de4&end=9649706eada1b2c68cf6504356efb058f68ad739&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions ❌ (primary) | - | - | 0 | | Regressions ❌ (secondary) | - | - | 0 | | Improvements ✅ (primary) | -0.3% | [-0.9%, -0.2%] | 21 | | Improvements ✅ (secondary) | -0.7% | [-5.9%, -0.1%] | 18 | | All ❌✅ (primary) | -0.3% | [-0.9%, -0.2%] | 21 | Revert "Auto merge of #127537 - veluca93:struct_tf, r=BoxyUwU" [#129854](https://github.com/rust-lang/rust/pull/129854) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=a48861a6279b386ad2b9c3518490181d238fe727&end=94885bc699512cfee8560e73c2a01ee6b4b76563&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions ❌ (primary) | - | - | 0 | | Regressions ❌ (secondary) | - | - | 0 | | Improvements ✅ (primary) | -0.4% | [-1.1%, -0.2%] | 81 | | Improvements ✅ (secondary) | -0.5% | [-2.2%, -0.2%] | 24 | | All ❌✅ (primary) | -0.4% | [-1.1%, -0.2%] | 81 | - Revert of an earlier PR that had larger than expected regressions. - Investigation is ongoing on how to land it without such large regressions. Apply size optimizations to panic machinery and some cold functions [#129063](https://github.com/rust-lang/rust/pull/129063) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=94885bc699512cfee8560e73c2a01ee6b4b76563&end=e71f9529121ca8f687e4b725e3c9adc3f1ebab4d&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions ❌ (primary) | 0.2% | [0.2%, 0.2%] | 2 | | Regressions ❌ (secondary) | - | - | 0 | | Improvements ✅ (primary) | -1.2% | [-3.0%, -0.3%] | 16 | | Improvements ✅ (secondary) | -1.0% | [-1.5%, -0.4%] | 4 | | All ❌✅ (primary) | -1.0% | [-3.0%, 0.2%] | 18 | #### Mixed Rewrite lint_expectations in a single pass. [#127313](https://github.com/rust-lang/rust/pull/127313) [(Comparison Link)](https://perf.rust-lang.org/compare.html?start=1a1cc050d8efc906ede39f444936ade1fdc9c6cb&end=a48861a6279b386ad2b9c3518490181d238fe727&stat=instructions:u) | (instructions:u) | mean | range | count | |:----------------------------------:|:-----:|:--------------:|:-----:| | Regressions ❌ (primary) | 0.4% | [0.3%, 0.4%] | 9 | | Regressions ❌ (secondary) | 0.6% | [0.2%, 1.5%] | 14 | | Improvements ✅ (primary) | -0.5% | [-1.5%, -0.2%] | 82 | | Improvements ✅ (secondary) | -0.7% | [-1.8%, -0.1%] | 58 | | All ❌✅ (primary) | -0.4% | [-1.5%, 0.4%] | 91 | - More improvements than regressions, marking as triaged. ## Nominated Issues [T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-compiler-nominated) - "Tracking peak total storage use" [rust#129808](https://github.com/rust-lang/rust/issues/129808) - nominated by @**Jubilee** - Context: last week our CI started to fail due to not having enough storage available - Questions for all teams: > - Are we aware of past efforts being aware of whether or not we have reduced the size? > - What information is [t-compiler] currently tracking re: size? > - What information would [t-compiler] like to have available re: size? - "Add Unicode block-drawing compiler output support" [rust#126597](https://github.com/rust-lang/rust/pull/126597) - Proposal from @**Esteban Küber** - Nominated by @**León Orell Liehr (fmease)** (assigned reviewer), asks if this proposal would benefit from some sort of agreement from T-compiler (MCP or other) - More context [here](https://github.com/rust-lang/rust/pull/126597#issuecomment-2267602708) and [here](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Unstable.20Unicode.20box.20drawing.20support.20for.20diagnostics.3A.20MCP.3F/near/467577067) [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) - "fix: get llvm type of global val" [rust#128820](https://github.com/rust-lang/rust/pull/128820) (last review activity: about 21 days ago) - cc @**Nikita Popov** - "Implement a lint for implicit autoref of raw pointer dereference - take 2" [rust#123239](https://github.com/rust-lang/rust/pull/123239) - cc: @**León Orell Liehr (fmease)** - "Apply `EarlyOtherwiseBranch` to scalar value" [rust#129047](https://github.com/rust-lang/rust/pull/129047) (last review activity: about 22 days ago) - cc: @**cjgillot** ## Next week's WG checkins None Next meetings' agenda draft: [hackmd link](https://hackmd.io/XV_FIeKwRx2TTtvsbVuTFA)

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