impl PartialEq<{str,String}> for {Path,PathBuf} (and reversed)

[Kixunil]

Comparison of paths and strings is expected to be possible and needed e.g. in tests. This change adds the impls os PartialEq between strings and paths, both owned and unsized, in both directions.

Because this is trait impl it's expected to be insta-stable.

ACP: rust-lang/libs-team#151

[rustbot]

r? @joshtriplett

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[rustbot]

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

[Kixunil]

@rustbot label +T-libs-api -T-libs

[ChrisDenton]

Since this is instantly stable, I think it's worth asking why these weren't implemented before. I doubt this omission was unintentional.

EDIT: Hm, looking at the proposed implementation I think my initial guess as to why was wrong. Still, my question stands,

[ChrisDenton]

Ah, looking at the above error it seems like this may cause type inference issues? In which case it would be a breaking change to implement this. See also previous attempts in #31861 and #76189

[Kixunil]

@ChrisDenton the errors in CI are just changed outputs in UI tests which is fine. I didn't have time to update them and will be unable for a few days I think. The linked issues seem like people gave up too soon but I will look later if different errors appear.

[ChrisDenton]

Fair enough. If it's just the case that people keep giving up too early then I don't have any problem. I just prefer to know, if possible, why something seemingly obvious hasn't been done before rather than assuming it's just an oversight.

[bors]

☔ The latest upstream changes (presumably #106215) made this pull request unmergeable. Please resolve the merge conflicts.

[pitaj]

@rustbot label -S-waiting-on-review +S-waiting-on-ACP

[workingjubilee]

r? libs-api

Needs FCP for a bunch of PartialEq between str and String with Path and PathBuf. ACP was already accepted.

[workingjubilee]

Though doesn't Deref handle some of them? Hmm...