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@matthiaskrgr matthiaskrgr commented Nov 22, 2025

Successful merges:

r? @ghost
@rustbot modify labels: rollup

Create a similar rollup

Muscraft and others added 27 commits November 18, 2025 19:07
…s, r=JonathanBrouwer

Warn against calls which mutate an interior mutable `const`-item

## `const_item_interior_mutations`

~~`interior_mutable_const_item_mutations`~~

~~`suspicious_mutation_of_interior_mutable_consts`~~

*warn-by-default*

The `const_item_interior_mutations` lint checks for calls which mutates an interior mutable const-item.

### Example

```rust
use std::sync::Once;

const INIT: Once = Once::new(); // using `INIT` will always create a temporary and
                                // never modify it-self on use, should be a `static`
                                // instead for shared use

fn init() {
    INIT.call_once(|| {
        println!("Once::call_once first call");
    });
}
```

```text
warning: mutation of an interior mutable `const` item with call to `call_once`
  --> a.rs:11:5
   |
11 |       INIT.call_once(|| {
   |       ^---
   |       |
   |  _____`INIT` is a interior mutable `const` item of type `std::sync::Once`
   | |
12 | |         println!("Once::call_once first call");
13 | |     });
   | |______^
   |
   = note: each usage of a `const` item creates a new temporary
   = note: only the temporaries and never the original `const INIT` will be modified
   = help: for more details on interior mutability see <https://doc.rust-lang.org/reference/interior-mutability.html>
   = note: `#[warn(const_item_interior_mutations)]` on by default
help: for a shared instance of `INIT`, consider making it a `static` item instead
   |
 6 - const INIT: Once = Once::new(); // using `INIT` will always create a temporary and
 6 + static INIT: Once = Once::new(); // using `INIT` will always create a temporary and
   |
```

### Explanation

Calling a method which mutates an interior mutable type has no effect as const-item are essentially inlined wherever they are used, meaning that they are copied directly into the relevant context when used rendering modification through interior mutability ineffective across usage of that const-item.

The current implementation of this lint only warns on significant `std` and `core` interior mutable types, like `Once`, `AtomicI32`, ... this is done out of prudence and may be extended in the future.

----

This PR is an targeted alternative to rust-lang#132146. It avoids false-positives by adding an internal-only attribute `#[rustc_should_not_be_called_on_const_items]` on methods and functions that mutates an interior mutale type through a shared reference (mutable refrences are already linted by the `const_item_mutation` lint).

It should also be noted that this is NOT an uplift of the more general [`clippy::borrow_interior_mutable_const`](https://rust-lang.github.io/rust-clippy/master/index.html#/borrow_interior_mutable_const) lint, which is a much more general lint regarding borrow of interior mutable types, but has false-positives that are completly avoided by this lint.

A simple [GitHub Search](https://github.com/search?q=lang%3Arust+%2F%28%3F-i%29const+%5Ba-zA-Z0-9_%5D*%3A+Once%2F&type=code) reveals many instance where the user probably wanted to use a `static`-item instead.

----

````@rustbot```` labels +I-lang-nominated +T-lang
cc ````@traviscross````
r? compiler

Fixes [IRLO - Forbidding creation of constant mutexes, etc](https://internals.rust-lang.org/t/forbidding-creation-of-constant-mutexes-etc/19005)
Fixes rust-lang#132028
Fixes rust-lang#40543
…ions, r=davidtwco

Address annotate-snippets test differences

When `annotate-snippets` became the default renderer on `nightly`, it came with a few rendering differences. I was not entirely happy with a few of the differences, and after talking with ``@davidtwco`` about them, I decided to address those that seemed like regressions.

r? ``@davidtwco``
…0, r=davidtwco

Fix the issue of unused assignment from MIR liveness checking

Fixes rust-lang#148960
Fixes rust-lang#148418

r? ``@davidtwco``

cc ``@cjgillot``

My first try on MIR related code, so it may not be the best fix.
…=davidtwco

feat: Enable annotate-snippets' simd feature

`annotate-snippets` `simd` feature enables the use of `memchr` when searching for `char`/`str`. This should hopefully improve performance when [`annotate-snippets` is passed large `source`](rust-lang#148188 (comment)).
Fix ICE when collecting opaques from trait method declarations

fixes rust-lang#148622

When using an `opaque` type as a `const` generic parameter, the compiler would attempt to collect TAIT from trait method declarations, causing an ICE by panicking in `hir_body_owned_by`.
Couple of refactors to SharedEmitter

I was trying to get rid of a dedicated `inline_asm_error` method in favor the regular error methods on `DiagCtxt` to allow replacing `SharedEmitter` with `sess.dcx()` when running on the main thread, but the `sess.source_map().new_source_file()` for the inline asm snippets prevents doing this. I'm going to solve the original motivating problem in a different way for this reason, but I figured these refactors do improve things a tiny bit.
…yukang

Handle cycles when checking impl candidates for `doc(hidden)`

Fixes rust-lang#149092
Move safe computation out of unsafe block
@rustbot rustbot added A-attributes Area: Attributes (`#[…]`, `#![…]`) A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. A-translation Area: Translation infrastructure, and migrating existing diagnostics to SessionDiagnostic labels Nov 22, 2025
@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-clippy Relevant to the Clippy team. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. rollup A PR which is a rollup labels Nov 22, 2025
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@bors2 try jobs=dist-ohos-aarch64

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rust-bors bot added a commit that referenced this pull request Nov 22, 2025
Rollup of 9 pull requests

try-job: dist-ohos-aarch64
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@bors r+ rollup=never p=5

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bors commented Nov 22, 2025

📌 Commit be4c672 has been approved by matthiaskrgr

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 Nov 22, 2025
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rust-bors bot commented Nov 22, 2025

☀️ Try build successful (CI)
Build commit: a872d29 (a872d291c4d1ea29213192a1df6c0c76106d6580, parent: 1dd43f247e6ec20a84dd017e4665266fa65e3a89)

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bors commented Nov 22, 2025

⌛ Testing commit be4c672 with merge 94b49fd...

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bors commented Nov 22, 2025

☀️ Test successful - checks-actions
Approved by: matthiaskrgr
Pushing 94b49fd to main...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Nov 22, 2025
@bors bors merged commit 94b49fd into rust-lang:main Nov 22, 2025
13 checks passed
@rustbot rustbot added this to the 1.93.0 milestone Nov 22, 2025
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📌 Perf builds for each rolled up PR:

PR# Message Perf Build Sha
#148407 Warn against calls which mutate an interior mutable const 372bf9d2acc068f56d6483bcc957660cda400102 (link)
#149065 Address annotate-snippets test differences 56c43c66877072a4d92503d0df1d2e1b15a2745f (link)
#149072 Fix the issue of unused assignment from MIR liveness checki… 3b29b8b848b3f94ea2fc54dc39d75fe3a7423f24 (link)
#149077 feat: Enable annotate-snippets' simd feature 73da0b3af8c97996370af7ef6057e03ae19d0943 (link)
#149168 Fix ICE when collecting opaques from trait method declarati… 770ef0decf6bcc188763bf89f1c56c6ea9b54eef (link)
#149180 Couple of refactors to SharedEmitter f12a4fe0ec069f8f46d56236a89bbab9fa20c4d4 (link)
#149185 Handle cycles when checking impl candidates for `doc(hidden… cadad9c7ada368bca49b0d0b5b0d9497d5979234 (link)
#149194 Move safe computation out of unsafe block fecb7e60ee3c7655fcec7b5e1d34e4e6b3ef0802 (link)
#149204 Fix typo in HashMap performance comment 90866db4e694eb8f44591a266f43dfe06747bbbc (link)

previous master: 4b1b6dde0c

In the case of a perf regression, run the following command for each PR you suspect might be the cause: @rust-timer build $SHA

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What is this? This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 4b1b6dd (parent) -> 94b49fd (this PR)

Test differences

Show 1786 test diffs

Stage 1

  • [ui] tests/ui/impl-trait/ice-148622-opaque-as-const-generics.rs: [missing] -> pass (J1)
  • [ui] tests/ui/lint/const-item-interior-mutations-const-atomics.rs: [missing] -> pass (J1)
  • [ui] tests/ui/lint/const-item-interior-mutations-const-cell.rs: [missing] -> pass (J1)
  • [ui] tests/ui/lint/const-item-interior-mutations-const.rs: [missing] -> pass (J1)
  • [ui] tests/ui/lint/unused/unused-assign-148960.rs: [missing] -> pass (J1)

Stage 2

  • [ui] tests/ui/impl-trait/ice-148622-opaque-as-const-generics.rs: [missing] -> pass (J0)
  • [ui] tests/ui/lint/const-item-interior-mutations-const-atomics.rs: [missing] -> pass (J0)
  • [ui] tests/ui/lint/const-item-interior-mutations-const-cell.rs: [missing] -> pass (J0)
  • [ui] tests/ui/lint/const-item-interior-mutations-const.rs: [missing] -> pass (J0)
  • [ui] tests/ui/lint/unused/unused-assign-148960.rs: [missing] -> pass (J0)

Additionally, 1776 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 94b49fd998d6723e0a9240a7cff5f9df37b84dd8 --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

  1. dist-x86_64-illumos: 6959.8s -> 5885.1s (-15.4%)
  2. dist-arm-linux-musl: 6654.6s -> 5638.5s (-15.3%)
  3. dist-aarch64-apple: 5697.0s -> 6548.4s (+14.9%)
  4. dist-powerpc-linux: 5553.3s -> 4807.5s (-13.4%)
  5. aarch64-msvc-1: 6377.1s -> 7184.9s (+12.7%)
  6. dist-aarch64-windows-gnullvm: 4721.3s -> 5134.3s (+8.7%)
  7. x86_64-mingw-2: 8002.1s -> 7333.9s (-8.3%)
  8. aarch64-apple: 8365.5s -> 7706.7s (-7.9%)
  9. x86_64-gnu-llvm-20: 2631.5s -> 2825.1s (+7.4%)
  10. i686-msvc-1: 10675.0s -> 9906.9s (-7.2%)
How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

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A-attributes Area: Attributes (`#[…]`, `#![…]`) A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. A-translation Area: Translation infrastructure, and migrating existing diagnostics to SessionDiagnostic merged-by-bors This PR was explicitly merged by bors. rollup A PR which is a rollup S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-clippy Relevant to the Clippy team. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-libs Relevant to the library team, which will review and decide on the PR/issue. T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue.

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