Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

make raw_eq precondition more restrictive #99511

Merged
merged 4 commits into from
Aug 12, 2022
Merged

make raw_eq precondition more restrictive #99511

merged 4 commits into from
Aug 12, 2022

Conversation

RalfJung
Copy link
Member

@RalfJung RalfJung commented Jul 20, 2022 •
edited
Loading

Specifically, don't allow comparing pointers that way. Comparing pointers is subtle because you have to talk about what happens to the provenance.

This matches what Miri already implements, and all existing users are fine with this.

If raw_eq on pointers is ever desired, we can adjust the intrinsic spec and Miri implementation as needed, but for now that seems just unnecessary. Also, this is a const intrinsic, and in const, comparing pointers this way is not possible -- so if we allow the intrinsic to compare pointers in general, we need to impose an extra restrictions saying that in const-context, pointers are not okay.

@rustbot rustbot added the T-libs Relevant to the library team, which will review and decide on the PR/issue. label Jul 20, 2022
@rustbot
Copy link
Collaborator

rustbot commented Jul 20, 2022

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label +T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

  • Stabilizing library features
  • Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
  • Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
  • Changing public documentation in ways that create new stability guarantees
  • Changing observable runtime behavior of library APIs

@rust-highfive
Copy link
Collaborator

r? @joshtriplett

(rust-highfive has picked a reviewer for you, use r? to override)

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 20, 2022
@RalfJung @mcol
fix typo
2d1c683 
Co-authored-by: Marco Colombo <[email protected]>
@RalfJung
Copy link
Member Author

RalfJung commented Aug 3, 2022

14 days without review, let's re-roll the dice...
r? compiler
(since it's just an intrinsic)

@RalfJung @steffahn
grammar
d1cace5 
Co-authored-by: Frank Steffahn <[email protected]>
@RalfJung @nnethercote
more typos
338d7c2 
Co-authored-by: Nicholas Nethercote <[email protected]>
wesleywiser
wesleywiser approved these changes Aug 11, 2022
View reviewed changes
Copy link
Member

@wesleywiser wesleywiser left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is there anything we should do to advertise that the safety invariant (at least, as documented) on this intrinsic has been updated?

@wesleywiser
Copy link
Member

@bors r+ rollup

@bors
Copy link
Contributor

bors commented Aug 11, 2022

📌 Commit 338d7c2 has been approved by wesleywiser

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 11, 2022
@RalfJung
Copy link
Member Author

Is there anything we should do to advertise that the safety invariant (at least, as documented) on this intrinsic has been updated?

I don't think so. It's an intrinsic, and a relatively obscure one.

@matthiaskrgr matthiaskrgr mentioned this pull request Aug 11, 2022
Merged
bors added a commit to rust-lang-ci/rust that referenced this pull request Aug 11, 2022
@bors
Auto merge of rust-lang#100426 - matthiaskrgr:rollup-0ks4dou, r=matth…
2ed0f29 
…iaskrgr

Rollup of 13 pull requests

Successful merges:

 - rust-lang#93896 (rustdoc: make item-infos dimmer on dark theme)
 - rust-lang#99337 (rustdoc: simplify highlight.rs)
 - rust-lang#99421 (add crt-static for android)
 - rust-lang#99500 (Fix flags when using clang as linker for Fuchsia)
 - rust-lang#99511 (make raw_eq precondition more restrictive)
 - rust-lang#99992 (Add `x.sh` and `x.ps1` shell scripts)
 - rust-lang#100112 (Fix test: chunks_mut_are_send_and_sync)
 - rust-lang#100203 (provide correct size hint for unsupported platform `CommandArgs`)
 - rust-lang#100307 (Fix rust-lang#96847)
 - rust-lang#100350 (Stringify non-shorthand visibility correctly)
 - rust-lang#100374 (Improve crate selection on rustdoc search results page)
 - rust-lang#100392 (Simplify visitors)
 - rust-lang#100418 (Add stability attributes to BacktraceStatus variants)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 37efd55 into rust-lang:master Aug 12, 2022
@rustbot rustbot added this to the 1.65.0 milestone Aug 12, 2022
@RalfJung RalfJung deleted the raw_eq branch August 13, 2022 12:05
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers

@mcol mcol mcol left review comments

@steffahn steffahn steffahn left review comments

@nnethercote nnethercote nnethercote left review comments

@wesleywiser wesleywiser wesleywiser approved these changes

Assignees

@wesleywiser wesleywiser

Labels
S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-libs Relevant to the library team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
1.65.0
Development

Successfully merging this pull request may close these issues.
9 participants
@RalfJung @rustbot @rust-highfive @wesleywiser @bors @nnethercote @steffahn @mcol @joshtriplett