---
# System prepended metadata

title: Lang/RfL meeting 2024-07-31
tags: [T-lang, minutes, design-meeting]

---

---
title: "Lang/RfL meeting 2024-07-31"
tags: ["T-lang", "design-meeting", "minutes"]
date: 2024-07-31
url: https://hackmd.io/w0lyM4haQY-UWkkqn4ISmQ
---

# Discussion

People: TC, Josh, tmandry, Miguel, Alice Ryhl, Benno Lossin, Boqun Feng, Gary Guo, Xiang, Andreas Hindborg, Mitchell Levy

https://rust-lang.github.io/rust-project-goals/2024h2/rfl_stable.html

https://github.com/nikomatsakis/rfcs/blob/rfl-project-goal/text/0000-rust-for-linux-project-goal-2024h2.md#ownership-and-other-resources

## Action items (from last meeting)

* Benno to do write-up for `Unique<T>`.
  - https://rust-lang.zulipchat.com/#narrow/stream/425075-rust-for-linux/topic/.60Unique.3CT.3E.60.20pointer.20type/near/454586934
  - https://hackmd.io/@y86-dev/HJW2MiSOC
* Miguel to talk to Jakub + Guillaume.
* Josh Triplett + TC to reach out to Debian about the edition timeline and see if we can find a solution here regarding Trixie. Maybe cc Miguel.

## Outreach to Debian

We sent out the message we had planned:

https://alioth-lists.debian.net/pipermail/pkg-rust-maintainers/2024-July/044870.html

And we've received a positive reply:

https://alioth-lists.debian.net/pipermail/pkg-rust-maintainers/2024-July/044887.html

They're in the middle of their big conference.  We're expecting to perhaps hear more after that.

## `Unique<T>`

https://hackmd.io/@y86-dev/HJW2MiSOC

Getting T-opsem to look at this is probably the right next step.

It may be worth opening an issue on the unsafe guidelines repository.

Then this could be turned into an RFC.

## CI changes

Miguel talked with Jaub and Guillaume.

They agreed with it, PRs sent and merged:

- https://github.com/rust-lang/rust/pull/128322
- https://github.com/rust-lang/rust/pull/128367

Single job run syntax: `try-job: x86_64-rust-for-linux`

Try permissions for the ping group? Not sure if that is a thing, Jakub suggested it.

- https://github.com/rust-lang/team/pull/1512
- Action Item: update PR and ping t-lang

`rustfmt` and Clippy probably to be enabled as well in the RFL CI job.
  + In the past we had an ICE on `rustfmt` on `-Zpretty=expanded` output, so that was an instance that could have been spotted if we add this.

## Arbitrary self types v2

We accepted the RFC.  We're waiting on some implementation there.

TC reached out to Adrian.  Adrian replied that it's going slow but steady.  He offered an update a couple weeks back here:

https://github.com/rust-lang/rust/issues/44874#issuecomment-2236916509

## `derive(SmartPointer)`

Making progress there; PRs are getting merged.

## `asm_goto`

Patch series in R4L mailing list: https://lore.kernel.org/rust-for-linux/20240628-tracepoint-v4-1-353d523a9c15@google.com/

The current design may not be the best way to do this, so we're looking into this further:

Zulip thread for design discussion: https://rust-lang.zulipchat.com/#narrow/stream/216763-project-inline-asm/topic/asm.20goto

C inline assembler have "i" constraint which allow a constant  to be added to the inline assembly even if it's a function argument: https://elixir.bootlin.com/linux/v6.10.2/source/arch/arm64/include/asm/jump_label.h#L26

GCC: https://gcc.gnu.org/onlinedocs/gcc/Simple-Constraints.html#index-constants-in-constraints

Something we may or may not want to revive:

https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/atomic.3A.3AOrdering.20as.20a.20const.20generic

https://rust-for-linux.zulipchat.com/#narrow/stream/288089-General/topic/Argument-position.20const.20generics

This relates to raw pointers in const generics.

asm block returning arbitrary typed value:

https://rust-lang.zulipchat.com/#narrow/stream/216763-project-inline-asm/topic/asm.20goto/near/410450102

The next step here is writing up a design document and proposing a design meeting.  Gary is interested in doing this.

## Extended `offset_of` syntax

There was just a stabilization of `offset_of_nested`:

https://github.com/rust-lang/rust/pull/128284

This doesn't stabilize it for enums, but RfL doesn't have a use case for that at the moment anyway.

So for RfL purposes, this crosses the item off the list.

## Pointers to statics in constants

The stabilization report is now up:

https://github.com/rust-lang/rust/issues/128183

We've proposed FCP merge.

## Sanitizers supported only when another flag is passed

Alice would like a reviewer for:

https://github.com/rust-lang/rust/pull/128348

Tyler will review it or find a reviewer.
