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New lint: Recommend using ptr::eq when possible#4596

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New lint: Recommend using ptr::eq when possible#4596
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tesuji:lint-ptr-eq

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@tesuji tesuji commented Sep 28, 2019

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changelog: Recommend using ptr::eq when possible

Closes #3661

@JohnTitor JohnTitor added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties label Sep 28, 2019
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bors commented Oct 8, 2019

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☔ The latest upstream changes (presumably #4592) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Oct 9, 2019

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☔ The latest upstream changes (presumably #4615) made this pull request unmergeable. Please resolve the merge conflicts.

@tesuji

tesuji commented Oct 9, 2019

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Network errors in mac builder.

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bors commented Oct 14, 2019

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☔ The latest upstream changes (presumably #4560) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Oct 18, 2019

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☔ The latest upstream changes (presumably #4683) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Oct 18, 2019

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☔ The latest upstream changes (presumably #4657) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Nov 7, 2019

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☔ The latest upstream changes (presumably #4788) made this pull request unmergeable. Please resolve the merge conflicts.

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bors commented Nov 23, 2019

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☔ The latest upstream changes (presumably #4839) made this pull request unmergeable. Please resolve the merge conflicts.

flip1995
flip1995 reviewed Nov 25, 2019
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Comment thread tests/ui/ptr_eq.fixed
@flip1995 flip1995 added the A-lint Area: New lints label Nov 25, 2019
@tesuji tesuji closed this Nov 28, 2019
@tesuji tesuji reopened this Nov 28, 2019
flip1995
flip1995 reviewed Nov 28, 2019
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Comment thread clippy_lints/src/ptr_eq.rs
LINT_MSG,
"try",
sugg,
Applicability::MachineApplicable,

@flip1995 flip1995 Nov 28, 2019

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How confident are you with the MachineApplicableility? I'M asking because of the formulation of

static LINT_MSG: &str = "use `std::ptr::eq` when applicable";

@tesuji tesuji Nov 30, 2019

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I've just added a macro check. But maybe there are more cases that I can't think of.

phansch
phansch reviewed Dec 4, 2019
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I'm just learning about raw pointers, as I've never really used FFI before. Apologies if it sounds a bit pedantic but I genuinely don't know most of this yet 🙇‍♂️

Comment thread clippy_lints/src/ptr_eq.rs Outdated
declare_clippy_lint! {
/// **What it does:** Use `std::ptr::eq` when applicable
///
/// **Why is this bad?** This can be used to compare `&T` references

@phansch phansch Dec 4, 2019

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What's This, the first word, meant to reference? ptr::eq? If yes, I think it would read better as ptr::eq can be used to ...

Comment thread clippy_lints/src/ptr_eq.rs
///
/// **Why is this bad?** This can be used to compare `&T` references
/// (which coerce to `*const T` implicitly) by their address rather than
/// comparing the values they point to.

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Is there another benefit in using ptr::eq, apart from being shorter?

Comment thread clippy_lints/src/ptr_eq.rs Outdated
Comment thread clippy_lints/src/ptr_eq.rs Outdated
Comment thread clippy_lints/src/ptr_eq.rs Outdated
Comment thread clippy_lints/src/ptr_eq.rs Outdated
@phansch phansch added S-waiting-on-author Status: This is awaiting some action from the author. (Use `@rustbot ready` to update this status) and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties labels Dec 5, 2019
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☔ The latest upstream changes (presumably #4889) made this pull request unmergeable. Please resolve the merge conflicts.

@tesuji

tesuji commented Dec 8, 2019

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Unfortunately, I don't think this lint is very useful.
cc @matthiaskrgr for #4596 (comment) ?

@phansch

phansch commented Dec 9, 2019

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@lzutao I think this could still fit as a style lint, no?

@tesuji tesuji force-pushed the lint-ptr-eq branch 3 times, most recently from 6fc0670 to b5a9c82 Compare December 10, 2019 04:31
@tesuji @phansch
New lint: Recommend using ptr::eq when possible
edc9371 
Co-Authored-By: Phil Hansch <dev@phansch.net>
@flip1995 flip1995 added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties and removed S-waiting-on-author Status: This is awaiting some action from the author. (Use `@rustbot ready` to update this status) labels Dec 11, 2019
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bors commented Dec 22, 2019

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☔ The latest upstream changes (presumably #4930) made this pull request unmergeable. Please resolve the merge conflicts.

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tesuji commented Dec 22, 2019

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Closed as inactive.

@tesuji tesuji closed this Dec 22, 2019
@tesuji tesuji deleted the lint-ptr-eq branch December 22, 2019 10:13
@flip1995 flip1995 added S-inactive-closed Status: Closed due to inactivity and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties labels Dec 22, 2019
@ambroisie ambroisie mentioned this pull request Oct 7, 2020
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bors added a commit that referenced this pull request Oct 9, 2020
@bors
Auto merge of #6130 - Ambroisie:lint-ptr-eq, r=Manishearth
947516f 
New lint: Recommend using `ptr::eq` when possible

This is based almost entirely on the code available in the previous PR #4596. I merely updated the code to make it compile.

Fixes #3661.

- [ ] I'm not sure about the lint name, but it was the one used in the original PR.
- [X] Added passing UI tests (including committed `.stderr` file)
- [X] `cargo test` passes locally
- [X] Executed `cargo dev update_lints`
- [X] Added lint documentation
- [X] Run `cargo dev fmt`

---

changelog: none
@hkalbasi

hkalbasi commented Jul 29, 2021

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finished in #6130
@rustbot label -S-inactive-closed

@rustbot rustbot removed the S-inactive-closed Status: Closed due to inactivity label Jul 29, 2021
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new lint: suggest ptr::eq() instead of "x as *const _ as usize == y as *const as usize"

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@tesuji @bors @phansch @hkalbasi @flip1995 @JohnTitor @rustbot