---
tags: weekly, rustc
---

# T-compiler Meeting Agenda 2023-05-11

## Announcements

- [steering: deny-by-default lints in unreachable code (bug vs QoL)](https://www.google.com/calendar/event?eid=NWNuYmxpb2w4YW9vaXN2bXI1c3JxZXUydmYgNnU1cnJ0Y2U2bHJ0djA3cGZpM2RhbWdqdXNAZw) at <time:2023-05-12T10:00:00-04:00>
- [Types team meeting](https://www.google.com/calendar/event?eid=MTg3MDhpdTc3YXBqMGMzbnNxanUwdWZnazhfMjAyMzA1MTVUMTQwMDAwWiA2dTVycnRjZTZscnR2MDdwZmkzZGFtZ2p1c0Bn) at <time:2023-05-15T10:00:00-04:00>
- Reminder: T-compiler and compiler-contributors are asked to check their emails and make sure they got their ballot for the council representative. Reach out to Felix or Wesley if you need assistance.
- Reminder: if you see a PR/issue that seems like there might be legal implications due to copyright/IP/etc, please let the Core team know (or at least message @_**pnkfelix** or @_**Wesley Wiser** so we can pass it along).

### Other WG meetings ([calendar link](https://calendar.google.com/calendar/embed?src=6u5rrtce6lrtv07pfi3damgjus%40group.calendar.google.com))
- [wg-async weekly](https://www.google.com/calendar/event?eid=N211N3RrYzVqcnVvNnBycGFrcW9mcjNocTNfMjAyMzA1MTFUMTYwMDAwWiA2dTVycnRjZTZscnR2MDdwZmkzZGFtZ2p1c0Bn) at <time:2023-05-11T12:00:00-04:00>
- [wg-debugging triage meeting](https://www.google.com/calendar/event?eid=NjAwbDEwNzNmMzVsNDZucnFsdDdwbGJrdDRfMjAyMzA1MTVUMTQwMDAwWiA2dTVycnRjZTZscnR2MDdwZmkzZGFtZ2p1c0Bn) at <time:2023-05-15T10:00:00-04:00>
- [wg-rls-2.0 weekly sync-up](https://www.google.com/calendar/event?eid=MXJnbzBscDExNHJjNmVsdGhsaW8xcDljMmdfMjAyMzA1MTVUMTUwMDAwWiA2dTVycnRjZTZscnR2MDdwZmkzZGFtZ2p1c0Bn) at <time:2023-05-15T11:00:00-04:00>

## MCPs/FCPs

- New MCPs (take a look, see if you like them!)
- "Runtime checks for occupied niches" [compiler-team#624](https://github.com/rust-lang/compiler-team/issues/624)
- "Tier 3 target proposal: bare-metal loongarch64" [compiler-team#628](https://github.com/rust-lang/compiler-team/issues/628)
- "Add support for Zephyr OS" [compiler-team#629](https://github.com/rust-lang/compiler-team/issues/629)
- "Add `mips64r6` option to `target_arch`" [compiler-team#632](https://github.com/rust-lang/compiler-team/issues/632)
- 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)
- "Rustc Contributor Program Major Change Proposal" [compiler-team#557](https://github.com/rust-lang/compiler-team/issues/557) (last review activity: 3 months ago)
- "Take MIR `Analysis` by `&mut`" [compiler-team#598](https://github.com/rust-lang/compiler-team/issues/598) (last review activity: about 48 days ago)
- "-C linker-flavor=clang" [compiler-team#601](https://github.com/rust-lang/compiler-team/issues/601) (last review activity: about 48 days ago)
- "Increase `TypeId`'s hash from 64 bits to 128 bits." [compiler-team#608](https://github.com/rust-lang/compiler-team/issues/608) (last review activity: about 20 days ago)
- "Disallow incoherent cfgs" [compiler-team#610](https://github.com/rust-lang/compiler-team/issues/610) (last review activity: about 27 days ago)
- "2024: Decrease debuginfo generated by `-Cdebuginfo=1`" [compiler-team#613](https://github.com/rust-lang/compiler-team/issues/613) (last review activity: about 20 days ago)
- "Cell Broadband Engine SPU support" [compiler-team#614](https://github.com/rust-lang/compiler-team/issues/614) (last review activity: about 27 days ago)
- "Revise error code documentation standard" [compiler-team#615](https://github.com/rust-lang/compiler-team/issues/615) (last review activity: about 20 days ago)
- Pending FCP requests (check your boxes!)
- "[mir-opt] SimplifyLocals should also clean up debuginfo" [rust#110702](https://github.com/rust-lang/rust/pull/110702#issuecomment-1528821029)
- Things in FCP (make sure you're good with it)
- "Add a blanket flag to enable/disable codegen UB checks" [compiler-team#625](https://github.com/rust-lang/compiler-team/issues/625)
- "Unimplement `unsized_locals`" [compiler-team#630](https://github.com/rust-lang/compiler-team/issues/630)
- "Experimental feature gate for `extern "crabi"` ABI" [compiler-team#631](https://github.com/rust-lang/compiler-team/issues/631)
- "Remove misleading target feature aliases" [rust#107707](https://github.com/rust-lang/rust/pull/107707)
- Accepted MCPs
- "Stable -C binary-dep-depinfo flag" [compiler-team#604](https://github.com/rust-lang/compiler-team/issues/604)
- "Integrate Enzyme into nightly rustc" [compiler-team#611](https://github.com/rust-lang/compiler-team/issues/611)
- "Add a `--print=unmap-path-prefixes` flag" [compiler-team#612](https://github.com/rust-lang/compiler-team/issues/612)
- "move constructors from `TyCtxt` to the constructed types" [compiler-team#616](https://github.com/rust-lang/compiler-team/issues/616)
- "Rename `NEEDS_SUBST` and `NEEDS_INFER`" [compiler-team#617](https://github.com/rust-lang/compiler-team/issues/617)
- "Enable the LLVM option `NoTrapAfterNoreturn` when `TrapUnreachable` is enabled." [compiler-team#618](https://github.com/rust-lang/compiler-team/issues/618)
- "Redesign bootstrap stages" [compiler-team#619](https://github.com/rust-lang/compiler-team/issues/619)
- "Policy for ICEs on incorrect usage of internal-only features" [compiler-team#620](https://github.com/rust-lang/compiler-team/issues/620)
- "Remove multi-field `repr(simd)`" [compiler-team#621](https://github.com/rust-lang/compiler-team/issues/621)
- "Add a new `--crate-version` flag to rustc" [compiler-team#622](https://github.com/rust-lang/compiler-team/issues/622)
- "Stronger typing for `DefId`s" [compiler-team#623](https://github.com/rust-lang/compiler-team/issues/623)
- Finalized FCPs (disposition merge)
- "Tracking Issue for `debugger_visualizer`" [rust#95939](https://github.com/rust-lang/rust/issues/95939)
- "Evaluate place expression in `PlaceMention`" [rust#104844](https://github.com/rust-lang/rust/pull/104844)
- "Add deployment-target --print flag for Apple targets" [rust#105354](https://github.com/rust-lang/rust/pull/105354)
- "Update the version of musl used on `*-linux-musl` targets to 1.2.3" [rust#107129](https://github.com/rust-lang/rust/pull/107129)
- "Only check outlives goals on impl compared to trait" [rust#109356](https://github.com/rust-lang/rust/pull/109356)
- "Stabilize raw-dylib, link_ordinal, import_name_type and -Cdlltool" [rust#109677](https://github.com/rust-lang/rust/pull/109677)
- "rustdoc: restructure type search engine to pick-and-use IDs" [rust#110371](https://github.com/rust-lang/rust/pull/110371)
- "Use fulfillment to check `Drop` impl compatibility" [rust#110577](https://github.com/rust-lang/rust/pull/110577)

### WG checkins

- @_*WG-async-foundations* by @**nikomatsakis** and @**tmandry** ([previous checkin](https://hackmd.io/EewyTLZXQpmtfaH633GU-A#WG-checkins)):
> Checkin text

- Generic Associated Types initiative by @**Jack Huey** ([previous checkin](https://hackmd.io/1yvNT5QMQLeHxEoMBaULJw#WG-checkins)):
> Checkin text

## Backport nominations

Tip: next to the `:beta:` tag, put the target version number (see the PR or ask if in doubt)

[T-compiler stable](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-compiler) / [T-compiler beta](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Astable-nominated+-label%3Astable-accepted+label%3AT-compiler)
- [1.70.0] :beta: "debuginfo: split method declaration and definition" [rust#111167](https://github.com/rust-lang/rust/pull/111167)
- nominated by @**cuviper** ([comment](https://github.com/rust-lang/rust/pull/111167#issuecomment-1536416391))
- Fixes #109730 and #109934 (regressions related to an previous LLVM upgrade, reporetd a crate and firefox not compiling when LTO=true)
<!--
/poll Approve beta backport of #111167?
approve
decline
don't know
-->
- No stable nominations for `T-compiler` this time.

[T-rustdoc stable](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Abeta-nominated+-label%3Abeta-accepted+label%3AT-rustdoc) / [T-rustdoc beta](https://github.com/rust-lang/rust/issues?q=is%3Aall+label%3Astable-nominated+-label%3Astable-accepted+label%3AT-rustdoc)
- No beta nominations for `T-rustdoc` this time.
- No stable nominations for `T-rustdoc` this time.

:back: / :shrug: / :hand:

## 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)
- Other issues [in progress or waiting on other teams](https://hackmd.io/XYr1BrOWSiqCrl8RCWXRaQ)

### 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)
- "Use 128 bits for TypeId hash" [rust#109953](https://github.com/rust-lang/rust/pull/109953) (last review activity: about 23 days ago)
- cc: @**davidtwco** probably ready for another review
- "Add armv8r-none-eabihf target for the Cortex-R52." [rust#110482](https://github.com/rust-lang/rust/pull/110482) (last review activity: about 22 days ago)
- seems the review is bouncing around. Can anyone help?
- "Fix target_feature 1.1 should print the list of missing target features" [rust#109710](https://github.com/rust-lang/rust/pull/109710) (last review activity: about 22 days ago)
- review assigned to @_**oli** but PR author mentions @**Michael Goulet (compiler-errors)** @**Jubilee** (since previously reviewed)

## 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)
- [62 T-compiler P-high issues](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AT-compiler+label%3AP-high)
- [29 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, 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, 2 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, 95 P-medium, 15 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` at 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` at this time.

[T-rustdoc](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AP-critical+label%3AT-rustdoc)
- No `P-critical` issues for `T-rustdoc` at 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 new p-high beta regressions

[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

N/A this week?

## Nominated Issues

[T-compiler](https://github.com/rust-lang/rust/issues?q=is%3Aopen+label%3AI-compiler-nominated)
- "Tracking Issue for `debugger_visualizer`" [rust#95939](https://github.com/rust-lang/rust/issues/95939)
- nominated by @**lcnr** after comment from @**ehuss** ([comment](https://github.com/rust-lang/rust/issues/95939#issuecomment-1537190916)), concern about stabilization as it is today
- either fix or revert - suggests @**Michael Goulet (compiler-errors)**
- "feat: add `expansion_growth_limit` attr as another expansion limit" [rust#103029](https://github.com/rust-lang/rust/pull/103029)
- PR work in progress, current design seems to be in need of some work. PR author @**Vincenzo Palazzo** asks for mentoring / design suggestions
- PR received comments, was also discussed on Zulip [here](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/macro.20grow.20limit.20expansion.20discussion) and [here](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/rustc_expand.20keep.20into.20count.20expansion.20limit.20also.20the))
- [comments from vincenzopalazzo]: a good summary of what it is going one this [this one](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/rustc_expand.20keep.20into.20count.20expansion.20limit.20also.20the/near/292808431)
- Some open questions are:
- This may result in a breaking change if we patch this case for all kind of macros (quote may impacted and this implies a very big numbers of macros)
- An idea is to patch only the buggy macros with the bang operator (mentioned in the PR), and then in a new edition put this for all the other macros?

[RFC](https://github.com/rust-lang/rfcs/issues?q=is%3Aopen+label%3AI-compiler-nominated)
- No I-compiler-nominated RFCs this time.

## Next week's WG checkins

- @_*WG-diagnostics* by @**Esteban Küber** and @**oli**
- @_*WG-rustc-dev-guide* by @**Santiago Pastorino** and @**Yuki Okushi|217081**

Agenda draft: https://hackmd.io/AvJQh432RbWk3nzBfR9_gA