Stream: t-compiler/wg-prioritization/alerts

Topic: #80925 Accessing DST field of packed struct calculates the …


triagebot (Feb 14 2021 at 14:08, on Zulip):

@WG-prioritization/alerts issue #80925 has been requested for prioritization.

Procedure

Léo Lanteri Thauvin (Feb 14 2021 at 14:11, on Zulip):

This sounds very specific

Léo Lanteri Thauvin (Feb 14 2021 at 14:13, on Zulip):

But indeed it's unsound

Léo Lanteri Thauvin (Feb 14 2021 at 14:15, on Zulip):

I'd say this is not P-critical because it's so specific (I mean, who uses DSTs and #[repr(packed)] in the same struct?)

Léo Lanteri Thauvin (Feb 14 2021 at 14:15, on Zulip):

I'd propose P-medium or P-high here

DPC (Feb 14 2021 at 16:09, on Zulip):

agree with p-medium for this

apiraino (Feb 14 2021 at 18:15, on Zulip):

Issue reporter opened a list of issues related to how Rust represents data layout (at least my limited understanding).

apiraino (Feb 14 2021 at 18:17, on Zulip):

I probably don't have the right context , just one question - is it ok if different issues in this set are assigned different priority levels? At a cursory look I see there are unsound behaviours when Rust is instructed to represent differently data layout and apparently this also varies depending on which compiler I am on

Joshua Nelson (Feb 14 2021 at 18:21, on Zulip):

I think so, yes - I kind of disagree that https://github.com/rust-lang/rust/issues/81996 is unsound, it could only cause unsoundness if someone using unsafe makes assumptions about the layout that to my knowledge aren't guarenteed by the compiler. In this instance, it is most certainly unsound because you don't need unsafe.

apiraino (Feb 14 2021 at 18:26, on Zulip):

ah interesting, thank you Joshua!!

apiraino (Feb 14 2021 at 18:27, on Zulip):

this stuff is a bit above my head so It's great to hear and compare opinions

Joshua Nelson (Feb 14 2021 at 18:29, on Zulip):

left a comment on #81996 asking the author to explain the unsound label

triagebot (Feb 17 2021 at 12:24, on Zulip):

Issue #80925's prioritization request has been removed.

hyd-dev (Mar 22 2021 at 08:08, on Zulip):

Although I removed the A-const-eval label, I'm uncertain if that was correct now... The second piece of code that @mahkoh pointed out, according to https://doc.rust-lang.org/nightly/nightly-rustc/rustc_mir/interpret/index.html, is really const-eval related.

Last update: Apr 10 2021 at 22:00UTC