Commit Graph

310172 Commits

Author SHA1 Message Date
Mads Marquart dd2159e75d Simplify jemalloc setup
Using the new `override_allocator_on_supported_platforms` feature in
`tikv-jemalloc-sys v0.6.1` we can avoid the manual statics.
2025-11-11 20:16:15 +01:00
bors 2636cb4c13 Auto merge of #148818 - Zalathar:rollup-4vujcg0, r=Zalathar
Rollup of 13 pull requests

Successful merges:

 - rust-lang/rust#148694 (std: support `RwLock` and thread parking on TEEOS)
 - rust-lang/rust#148712 (Port `cfg_select!` to the new attribute parsing system)
 - rust-lang/rust#148760 (rustc_target: hide TargetOptions::vendor)
 - rust-lang/rust#148771 (IAT: Reinstate early bailout)
 - rust-lang/rust#148775 (Fix a typo in the documentation for the strict_shr function)
 - rust-lang/rust#148779 (Implement DynSend and DynSync for std::panic::Location.)
 - rust-lang/rust#148781 ([rustdoc] Remove unneeded `allow(rustc::potential_query_instability)`)
 - rust-lang/rust#148783 (add test for assoc type norm wf check)
 - rust-lang/rust#148785 (Replace `master` branch references with `main`)
 - rust-lang/rust#148791 (fix "is_closure_like" doc comment)
 - rust-lang/rust#148792 (Prefer to use file.stable_id over file.name from source map)
 - rust-lang/rust#148805 (rustc-dev-guide subtree update)
 - rust-lang/rust#148807 (Document (and test) a problem with `Clone`/`Copy` deriving.)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-11-11 13:30:50 +00:00
Stuart Cook 224ff38814 Rollup merge of #148807 - nnethercote:doc-Copy-Clone-problem, r=saethlin
Document (and test) a problem with `Clone`/`Copy` deriving.

I think this is useful information. I have worked on `derive` impls quite a bit and didn't know about this issue until today.

r? `@saethlin`
2025-11-11 21:11:57 +11:00
Stuart Cook b30c0045a9 Rollup merge of #148805 - tshepang:rdg-sync, r=tshepang
rustc-dev-guide subtree update

Subtree update of `rustc-dev-guide` to https://github.com/rust-lang/rustc-dev-guide/commit/02ba22e3a9b6c26946b0430e9f49e52d4c573381.

Created using https://github.com/rust-lang/josh-sync.

r? `@ghost`
2025-11-11 21:11:56 +11:00
Stuart Cook a929960b05 Rollup merge of #148792 - chenyukang:yukang-fix-file-name, r=Muscraft
Prefer to use file.stable_id over file.name from source map

From https://github.com/rust-lang/rust/pull/148735#discussion_r2508484125

r? `@Muscraft`
2025-11-11 21:11:55 +11:00
Stuart Cook c9158cef3e Rollup merge of #148791 - luca3s:fix-doc-comment, r=lqd
fix "is_closure_like" doc comment

Noticed that the [docs](https://doc.rust-lang.org/nightly/nightly-rustc/rustc_middle/ty/struct.TyCtxt.html#method.is_closure_like) stopped in the middle of the sentence. The text exists, but wasn't rendered because it was a regular comment.
2025-11-11 21:11:55 +11:00
Stuart Cook 3382d31b99 Rollup merge of #148785 - reddevilmidzy:rename-to-main, r=Kobzol
Replace `master` branch references with `main`

Additional work on branch name changes

r? ```@Kobzol```

related pr: https://github.com/rust-lang/rust/pull/148564
2025-11-11 21:11:54 +11:00
Stuart Cook 561d0a1792 Rollup merge of #148783 - lcnr:add-soundness-test, r=BoxyUwU
add test for assoc type norm wf check

This is soundness critical 😁 sure is helpful to have tests for that. cc ``@rust-lang/types``

r? ``@BoxyUwU``
2025-11-11 21:11:53 +11:00
Stuart Cook 2171eeeb6a Rollup merge of #148781 - GuillaumeGomez:rm-unneeded-attr, r=yotamofek
[rustdoc] Remove unneeded `allow(rustc::potential_query_instability)`

Originally replaced it with an `expect` and since it failed compilation because it wasn't triggered, I removed it.
2025-11-11 21:11:53 +11:00
Stuart Cook 58b44fc0f0 Rollup merge of #148779 - zachs18:panic-location-dynsendsync, r=nnethercote
Implement DynSend and DynSync for std::panic::Location.

Allows the compiler to build with the `debug_refcell` stdlib cargo feature.

With `rust.std-features = ["debug_refcell"]` in bootstrap.toml, `./x.py build --stage 2` fails before this patch, and succeeds afterwards.

<details> <summary>error for `./x.py build --stage 2` before this patch</summary>

```Rust
error[E0277]: `NonNull<str>` doesn't implement `DynSync`. Add it to `rustc_data_structures::marker` or use `IntoDynSyncSend` if it's already `Sync`
    --> compiler/rustc_query_system/src/dep_graph/serialized.rs:719:33
     |
 719 |           let results = broadcast(|_| {
     |  _______________________---------_^
     | |                       |
     | |                       required by a bound introduced by this call
 720 | |             let mut local = self.local.borrow_mut();
...    |
 734 | |         });
     | |_________^ within `Location<'static>`, the trait `DynSync` is not implemented for `NonNull<str>`
     |
note: required because it appears within the type `Location<'static>`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/library/core/src/panic/location.rs:39:12
     |
  39 | pub struct Location<'a> {
     |            ^^^^^^^^
     = note: required for `&'static Location<'static>` to implement `DynSend`
note: required because it appears within the type `std::option::Option<&'static Location<'static>>`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/library/core/src/option.rs:599:10
     |
 599 | pub enum Option<T> {
     |          ^^^^^^
note: required because it appears within the type `std::cell::UnsafeCell<std::option::Option<&'static Location<'static>>>`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/library/core/src/cell.rs:2289:12
     |
2289 | pub struct UnsafeCell<T: ?Sized> {
     |            ^^^^^^^^^^
note: required because it appears within the type `Cell<std::option::Option<&'static Location<'static>>>`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/library/core/src/cell.rs:313:12
     |
 313 | pub struct Cell<T: ?Sized> {
     |            ^^^^
note: required because it appears within the type `RefCell<LocalEncoderState>`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/library/core/src/cell.rs:822:12
     |
 822 | pub struct RefCell<T: ?Sized> {
     |            ^^^^^^^
     = note: required for `rustc_data_structures::sync::WorkerLocal<RefCell<LocalEncoderState>>` to implement `DynSync`
note: required because it appears within the type `EncoderState<D>`
    --> compiler/rustc_query_system/src/dep_graph/serialized.rs:546:8
     |
 546 | struct EncoderState<D: Deps> {
     |        ^^^^^^^^^^^^
     = note: required because it appears within the type `&EncoderState<D>`
note: required because it's used within this closure
    --> compiler/rustc_query_system/src/dep_graph/serialized.rs:719:33
     |
 719 |         let results = broadcast(|_| {
     |                                 ^^^
note: required by a bound in `rustc_data_structures::sync::broadcast`
    --> /home/zachary/opt_mount/zachary/Programming/rust-compiler-2/compiler/rustc_data_structures/src/sync/parallel.rs:239:56
     |
 239 | pub fn broadcast<R: DynSend>(op: impl Fn(usize) -> R + DynSync) -> Vec<R> {
     |                                                        ^^^^^^^ required by this bound in `broadcast`

For more information about this error, try `rustc --explain E0277`.
error: could not compile `rustc_query_system` (lib) due to 1 previous error
warning: build failed, waiting for other jobs to finish...
Build completed unsuccessfully in 0:02:04
```

</details>
2025-11-11 21:11:52 +11:00
Stuart Cook 0c615a1adb Rollup merge of #148775 - reddevilmidzy:fix-typo, r=joboet
Fix a typo in the documentation for the strict_shr function

fix: rust-lang/rust#148761
2025-11-11 21:11:51 +11:00
Stuart Cook 24e0724c6b Rollup merge of #148771 - fmease:iat-reinstate-early-elim, r=BoxyUwU
IAT: Reinstate early bailout

Apparently, some people are already using IATs in their projects and get blocked by https://github.com/rust-lang/rust/issues/142006#issuecomment-3508543649 (cc dupes https://github.com/rust-lang/rust/issues/143952 & https://github.com/rust-lang/rust/issues/148535). Since the (temporary) fix is so trivial, let's just do it.

Addresses https://github.com/rust-lang/rust/issues/142006#issuecomment-3508543649.

cc ```@luissantosHCIT``` (https://github.com/rust-lang/rust/issues/148535).

r? ```@BoxyUwU```
2025-11-11 21:11:50 +11:00
bors 9312cd6d38 Auto merge of #148817 - Zalathar:rollup-tf5ti2m, r=Zalathar
Rollup of 15 pull requests

Successful merges:

 - rust-lang/rust#141470 (Add new `function_casts_as_integer` lint)
 - rust-lang/rust#143619 (`c_variadic`: Add future-incompatibility warning for `...` arguments without a pattern outside of `extern` blocks)
 - rust-lang/rust#146495 (rustdoc: Erase `#![doc(document_private_items)]`)
 - rust-lang/rust#147771 (Rename `*exact_{div,shr,shl}` to `*{div,shr,shl}_exact`)
 - rust-lang/rust#147833 (rustdoc-json: move `target` to `json::conversions`)
 - rust-lang/rust#147955 (compiletest: Migrate `TestProps` directive handling to a system of named handlers)
 - rust-lang/rust#148480 (Add `Steal::risky_hack_borrow_mut`)
 - rust-lang/rust#148506 (Special case detecting `'static` lifetime requirement coming from `-> Box<dyn Trait>`)
 - rust-lang/rust#148508 (Provide more context when mutably borrowing an imutably borrowed value)
 - rust-lang/rust#148530 (update the bootstrap readme)
 - rust-lang/rust#148608 (Add test for --test-builder success path)
 - rust-lang/rust#148636 (bootstrap: respect `build.python` on macOS)
 - rust-lang/rust#148639 (test(rustdoc): move tests into jump-to-def)
 - rust-lang/rust#148647 (Check unsafety for non-macro attributes in `validate_attr`)
 - rust-lang/rust#148667 (a few small clippy fixes)

r? `@ghost`
`@rustbot` modify labels: rollup
2025-11-11 10:11:49 +00:00
Stuart Cook d738f03a27 Rollup merge of #148760 - tamird:avoid-vendor-logic, r=madsmtm
rustc_target: hide TargetOptions::vendor

Discussed in https://github.com/rust-lang/rust/pull/148531#discussion_r2507383167.

r? `````@bjorn3`````
2025-11-11 21:11:49 +11:00
Stuart Cook e26b42333d Rollup merge of #148712 - JonathanBrouwer:cfg_select, r=jdonszelmann
Port `cfg_select!` to the new attribute parsing system

Best reviewed commit by commit, since it involves some moving around of code

r? `````@jdonszelmann`````
2025-11-11 21:11:48 +11:00
Stuart Cook 3150714f40 Rollup merge of #148694 - joboet:teeos-sync, r=ChrisDenton
std: support `RwLock` and thread parking on TEEOS

Since TEEOS supports pthread mutexes and condvars, it can share the pthread-based thread parking implementation and thus also the queue-based `RwLock` implementation used on other platforms.

CC ``@petrochenkov`` ``@Sword-Destiny``
2025-11-11 21:11:47 +11:00
Stuart Cook 16944b814b Rollup merge of #148667 - hkBst:clippy-fix-14, r=Kivooeo
a few small clippy fixes
2025-11-11 21:09:42 +11:00
Stuart Cook 7327bbc811 Rollup merge of #148647 - JonathanBrouwer:unsafe_attr_refactor, r=jdonszelmann
Check unsafety for non-macro attributes in `validate_attr`

r? `````@jdonszelmann`````

Also adds a test for a previously untested case, unnecessary unsafe on a proc macro attribute

In preparation for https://github.com/rust-lang/rust/issues/148453
2025-11-11 21:09:41 +11:00
Stuart Cook f342c62537 Rollup merge of #148639 - midsterx:test/rustdoc, r=GuillaumeGomez
test(rustdoc): move tests into jump-to-def

Fixes https://github.com/rust-lang/rust/issues/148548
2025-11-11 21:09:40 +11:00
Stuart Cook e8404e4e7d Rollup merge of #148636 - xSetech:boostrap/set-python-on-macos, r=jieyouxu
bootstrap: respect `build.python` on macOS

The `python()` method was hardcoded to return `/usr/bin/python3` on macOS, ignoring the `build.python` config option. This change respects the config while maintaining the system Python as the default.
2025-11-11 21:09:39 +11:00
Stuart Cook 303dd1cb35 Rollup merge of #148608 - osamakader:doc-test-builder, r=GuillaumeGomez
Add test for --test-builder success path

Fixes rust-lang/rust#148586
2025-11-11 21:09:39 +11:00
Stuart Cook 3227f260f7 Rollup merge of #148530 - Shourya742:2025-11-05-update-bootstrap-documentation, r=Kobzol
update the bootstrap readme

This PR updates the bootstrap readme and makes it consistent with the latest stage 0 redesign.

r? ```@Kobzol```
2025-11-11 21:09:38 +11:00
Stuart Cook 417bea36ef Rollup merge of #148508 - estebank:issue-74617, r=nnethercote
Provide more context when mutably borrowing an imutably borrowed value

Point at statics and consts being mutable borrowed or written to:

```
error[E0594]: cannot assign to immutable static item `NUM`
  --> $DIR/E0594.rs:4:5
   |
LL | static NUM: i32 = 18;
   | --------------- this `static` cannot be written to
...
LL |     NUM = 20;
   |     ^^^^^^^^ cannot assign
```

Point at the expression that couldn't be mutably borrowed from a pattern:

```
error[E0596]: cannot borrow data in a `&` reference as mutable
  --> $DIR/mut-pattern-of-immutable-borrow.rs:19:14
   |
LL |     match &arg.field {
   |           ---------- this cannot be borrowed as mutable
LL |         Some(ref mut s) => s.push('a'),
   |              ^^^^^^^^^ cannot borrow as mutable
```

Partially address rust-lang/rust#74617.
2025-11-11 21:09:38 +11:00
Stuart Cook eb415e9a25 Rollup merge of #148506 - estebank:issue-41966, r=davidtwco
Special case detecting `'static` lifetime requirement coming from `-> Box<dyn Trait>`

```
error[E0310]: the parameter type `R` may not live long enough
  --> $DIR/implicit-static-lifetime-in-dyn-trait-return-type.rs:10:5
   |
LL | fn bb<R>(r: R) -> Box<dyn Foo> {
   |                       ------- this `dyn Trait` has an implicit `'static` lifetime bound
LL |     Box::new(Bar(r))
   |     ^^^^^^^^^^^^^^^^
   |     |
   |     the parameter type `R` must be valid for the static lifetime...
   |     ...so that the type `R` will meet its required lifetime bounds
   |
help: consider adding an explicit lifetime bound
   |
LL | fn bb<R: 'static>(r: R) -> Box<dyn Foo> {
   |        +++++++++
```

Partly address rust-lang/rust#41966 and rust-lang/rust#54753. rust-lang/rust#103849, which shows a case where there's an intermediary binding, is not addressed at all, as aren't cases *other* than `Box<dyn Trait>` return type.
2025-11-11 21:09:37 +11:00
Stuart Cook 01ae075dd1 Rollup merge of #148480 - Lysxia:steal-mut, r=davidtwco
Add `Steal::risky_hack_borrow_mut`

I'm working on a rustc driver (Creusot) which needs to modify the MIR read by two queries, `mir_borrowck` and `check_liveness`, in different ways for each query. Both of these queries use `mir_promoted` to read the MIR, which is immutable (until it is stolen).

This adds an escape hatch so rustc drivers can mutate MIR for specific queries. And this removes `get_mut` which is unused and also unusable now that there's no way to get a `&mut Steal` from the rustc API.

Another approach may be to override the queries to modify the MIR after having read it from `mir_promoted`. However the implementation of queries is largely hidden, so I can't just copy their code to then modify it. A solution would be to parameterize the queries with callbacks which get instantiated with `mir_promoted` by default, but that seems more involved and ad hoc. That's why I'm proposing this smaller change instead.
2025-11-11 21:09:36 +11:00
Stuart Cook 24873aac00 Rollup merge of #147955 - Zalathar:handlers, r=jieyouxu
compiletest: Migrate `TestProps` directive handling to a system of named handlers

One of the very silly things about directive processing in compiletest is that for each directive in the test file, we proceed to check it against dozens of different directive names in linear sequence, without any kind of indexed lookup, and without any early-exit after a known directive name is found (unless a panic occurs).

This PR is a big step away from that, by taking the `iter_directives` loop in `TestProps::load_from` and making all of its directive processing dispatch to a hashtable of individual name-specific handlers instead.

---

The handler system is set up in a way that should allow us to add capabilities or change the implementation as needed, without having to mass-modify the existing handlers (e.g. this is why the `handler` and `multi_handler` functions are used).

---

This PR is focused on mass-migrating all of the `TestProps` directive processing into handlers. Most of the resulting handlers could obviously be simplified further (e.g. by avoiding the redundant name checks that were needed in the pre-migration code), but I've avoided doing any such simplifications in this PR to keep its scope limited and make reviewing easier.

The patches in this PR have been arranged so that the main migration can be inspected with `git diff --color-moved --color-moved-ws=ignore-all-space` to verify that it moves all of the relevant lines intact, without modifying or discarding any of them.

r? jieyouxu
2025-11-11 21:09:36 +11:00
Stuart Cook c7bfd7f599 Rollup merge of #147833 - aDotInTheVoid:rdj-shuffle, r=camelid
rustdoc-json: move `target` to `json::conversions`

It belongs here, because it moves from a `rustc_*` type to a `rustdoc_json_types` type.

r? ```````@GuillaumeGomez```````
2025-11-11 21:09:35 +11:00
Stuart Cook 044c079b15 Rollup merge of #147771 - nxsaken:div_shlr_exact, r=dtolnay
Rename `*exact_{div,shr,shl}` to `*{div,shr,shl}_exact`

Related to rust-lang/rust#144336 and rust-lang/rust#139911, see https://github.com/rust-lang/rust/issues/139911#issuecomment-3406807537. I haven't touched the `exact_div`, `exact_udiv` and `exact_sdiv` intrinsics. Let me know if I should.
2025-11-11 21:09:34 +11:00
Stuart Cook 6487148d80 Rollup merge of #146495 - fmease:rustdoc-erase-doc-priv-items-attr, r=GuillaumeGomez
rustdoc: Erase `#![doc(document_private_items)]`

I just found out about the existence of `#![doc(document_private_items)]`. Apparently it was added by PR rust-lang/rust#50669 back in 2018 without any tests or docs as a replacement for some specific forms of the removed `#![doc(passes)]` / `#![doc(no_default_passes)]`.

However, rustc and rustdoc actually emit the deny-by-default lint `invalid_doc_attributes` for it (but if you allow it, the attribute does function)! To be more precise since PR rust-lang/rust#82708 (1.52, May 2021) which introduced lint `invalid_doc_attributes`, rust{,do}c has emitted a future-incompat warning for this attribute. And since PR rust-lang/rust#111505 (1.78, May 2024) that lint is deny by default. I presume nobody knew this attribute existed and thus it was never allowlisted.

Given the fact that since 2021 nobody has ever opened a ticket ([via](https://github.com/rust-lang/rust/issues?q=is%3Aissue+document_private_items)) complaining about the lint emission and the fact that GitHub code search doesn't yield any actual uses ([via](https://github.com/search?q=%2F%23%21%5C%5Bdoc%5C%28.*%3Fdocument_private_items%2F+language%3ARust&type=code&ref=advsearch)), I'm led to believe that nobody knows about and uses this attribute.

I don't find the existence of this attribute to be justified since in my view the flag `--document-private-items` is strictly superior: In most if not all cases, you don't want to "couple" your crate with this "mode" even if you gate it behind a cfg; instead, you most likely want to set this manually at invocation time, via a build config file like `.cargo/config.toml` or via a command runner like `just` I'd say.

Because of this I propose to wipe this attribute from existence. I don't believe it's worth cratering this (i.e., temporarily emitting a hard error for this attribute and running crater) given the fact that it's been undocumented since forever and led to a warning for years.
2025-11-11 21:09:33 +11:00
Stuart Cook 3538bc18fe Rollup merge of #143619 - beetrees:varargs-named, r=jdonszelmann
`c_variadic`: Add future-incompatibility warning for `...` arguments without a pattern outside of `extern` blocks

This PR makes `...` arguments without a pattern in non-foreign functions (such as the argument in `unsafe extern "C" fn f(...) {}`) a future-compatibility warning; making this error would be consistent with how `unsafe extern "C" fn f(u32) {}` is handled. Allowing `...` arguments without a pattern in non-foreign functions is a source of confusion for programmers coming from C, where the `...` parameter is never named and instead calling `va_start` is required; disallowing `...` arguments without a pattern also improves the overall consistency of the Rust language by matching the treatment of other arguments without patterns. `...` arguments without a pattern in `extern` blocks (such as `unsafe extern "C" { fn f(...); }`) continue to compile without warnings after this PR, as they are already stable and heavily used (and don't cause the mentioned confusion as they are just being used in function declarations).

As all the syntax gating for `c_variadic` has been done post-expansion, this is technically a breaking change. In particular, code like this has compiled on stable since Rust 1.35.0:
```rust
#[cfg(any())] // Equivalent to the more recent #[cfg(false)]
unsafe extern "C" fn bar(_: u32, ...) {}
```
Since this is more or less a stability hole and a Crater run shows only the `binrw` crate is using this, I think it would be ok to break this. This will require a lang FCP.

The idea of rejecting `...` pre-expansion was first raised here https://github.com/rust-lang/rust/pull/143546#issuecomment-3043142052.

Tracking issue: rust-lang/rust#44930
cc `@folkertdev` `@workingjubilee`
r? `@joshtriplett`
2025-11-11 21:09:33 +11:00
Stuart Cook 5b9211c5b3 Rollup merge of #141470 - GuillaumeGomez:function_casts_as_integer, r=urgau
Add new `function_casts_as_integer` lint

The `function_casts_as_integer` lint detects cases where users cast a function pointer into an integer.

*warn-by-default*

### Example

```rust
fn foo() {}
let x = foo as usize;
```

```
warning: casting a function into an integer implicitly
  --> $DIR/function_casts_as_integer.rs:9:17
   |
LL |     let x = foo as usize;
   |                 ^^^^^^^^
   |
help: add `fn() as usize`
   |
LL |     let x = foo as fn() as usize;
   |                 +++++++
```

### Explanation

You should never cast a function directly into an integer but go through a cast as `fn` first to make it obvious what's going on. It also allows to prevent confusion with (associated) constants.

Related to https://github.com/rust-lang/rust/issues/81686 and https://stackoverflow.com/questions/68701177/whats-the-meaning-of-casting-a-rust-enum-variant-to-a-numeric-data-type

r? ````@urgau````
2025-11-11 21:09:32 +11:00
lcnr 2570c2322b add test for assoc type norm wf check 2025-11-11 11:05:47 +01:00
bors c8f22ca269 Auto merge of #148737 - zachs18:unit-is-zero, r=joboet
Implement IsZero for (), and optimize `IsZero::is_zero` for arrays

These are probably not super useful optimizations, but they make it so that `vec![expr; LARGE_LENGTH]` has better performance for some `expr`s, e.g.

* array of length zero in debug mode
* tuple containing `()` and zero-valued integers in debug and release mode
* array of `()` or other zero-sized `IsZero` type in debug mode

<details> <summary>very rough benchmarks</summary>

```Rust
use std::time::Instant;
use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};

struct NonCopyZst;
static COUNTER: AtomicUsize = AtomicUsize::new(0);

impl Clone for NonCopyZst {
    fn clone(&self) -> Self {
        COUNTER.fetch_add(1, Relaxed);
        Self
    }
}

macro_rules! timeit {
    ($e:expr) => {
        let start = Instant::now();
        _ = $e;
        println!("{:56}: {:?}", stringify!($e), start.elapsed());
    };
}

fn main() {
    timeit!(vec![[String::from("hello"); 0]; 1_000_000_000]); // gets a lot better in debug mode
    timeit!(vec![(0u8, (), 0u16); 1_000_000_000]); // gets a lot better in debug *and* release mode
    timeit!(vec![[[(); 37]; 1_000_000_000]; 1_000_000_000]); // gets a lot better in debug mode
    timeit!(vec![[NonCopyZst; 0]; 1_000_000_000]); // gets a lot better in debug mode
    timeit!(vec![[[1u8; 0]; 1_000_000]; 1_000_000]); // gets a little bit better in debug mode
    timeit!(vec![[[(); 37]; 1_000_000]; 1_000_000]); // gets a little bit better in debug mode
    timeit!(vec![[[1u128; 0]; 1_000_000]; 1_000_000]); // gets a little bit better in debug mode

    // check that we don't regress existing optimizations
    timeit!(vec![(0u8, 0u16); 1_000_000_000]); // about the same time
    timeit!(vec![0u32; 1_000_000_000]); // about the same time

    // check that we still call clone for non-IsZero ZSTs
    timeit!(vec![[const { NonCopyZst }; 2]; 1_000]); // about the same time
    assert_eq!(COUNTER.load(Relaxed), 1998);
    timeit!(vec![NonCopyZst; 10_000]); // about the same time
    assert_eq!(COUNTER.load(Relaxed), 1998 + 9_999);
}

```

```rs
$ cargo +nightly run
// ...
vec![[String::from("hello"); 0]; 1_000_000_000]         : 11.13999724s
vec![(0u8, (), 0u16); 1_000_000_000]                    : 5.254646651s
vec![[[(); 37]; 1_000_000_000]; 1_000_000_000]          : 2.738062531s
vec![[NonCopyZst; 0]; 1_000_000_000]                    : 9.483690922s
vec![[[1u8; 0]; 1_000_000]; 1_000_000]                  : 2.919236ms
vec![[[(); 37]; 1_000_000]; 1_000_000]                  : 2.927755ms
vec![[[1u128; 0]; 1_000_000]; 1_000_000]                : 2.931486ms
vec![(0u8, 0u16); 1_000_000_000]                        : 19.46µs
vec![0u32; 1_000_000_000]                               : 9.34µs
vec![[const { NonCopyZst }; 2]; 1_000]                  : 31.88µs
vec![NonCopyZst; 10_000]                                : 36.519µs
```

```rs
$ cargo +dev run
// ...
vec![[String::from("hello"); 0]; 1_000_000_000]         : 4.12µs
vec![(0u8, (), 0u16); 1_000_000_000]                    : 16.299µs
vec![[[(); 37]; 1_000_000_000]; 1_000_000_000]          : 210ns
vec![[NonCopyZst; 0]; 1_000_000_000]                    : 210ns
vec![[[1u8; 0]; 1_000_000]; 1_000_000]                  : 170ns
vec![[[(); 37]; 1_000_000]; 1_000_000]                  : 110ns
vec![[[1u128; 0]; 1_000_000]; 1_000_000]                : 140ns
vec![(0u8, 0u16); 1_000_000_000]                        : 11.56µs
vec![0u32; 1_000_000_000]                               : 10.71µs
vec![[const { NonCopyZst }; 2]; 1_000]                  : 36.08µs
vec![NonCopyZst; 10_000]                                : 73.21µs
```

(checking release mode to make sure this doesn't regress perf there)

```rs
$ cargo +nightly run --release
// ...
vec![[String::from("hello"); 0]; 1_000_000_000]         : 70ns
vec![(0u8, (), 0u16); 1_000_000_000]                    : 1.269457501s
vec![[[(); 37]; 1_000_000_000]; 1_000_000_000]          : 10ns
vec![[NonCopyZst; 0]; 1_000_000_000]                    : 20ns
vec![[[1u8; 0]; 1_000_000]; 1_000_000]                  : 10ns
vec![[[(); 37]; 1_000_000]; 1_000_000]                  : 20ns
vec![[[1u128; 0]; 1_000_000]; 1_000_000]                : 20ns
vec![(0u8, 0u16); 1_000_000_000]                        : 20ns
vec![0u32; 1_000_000_000]                               : 20ns
vec![[const { NonCopyZst }; 2]; 1_000]                  : 2.66µs
vec![NonCopyZst; 10_000]                                : 13.39µs
```

```rs
$ cargo +dev run --release
vec![[String::from("hello"); 0]; 1_000_000_000]         : 90ns
vec![(0u8, (), 0u16); 1_000_000_000]                    : 30ns
vec![[[(); 37]; 1_000_000_000]; 1_000_000_000]          : 20ns
vec![[NonCopyZst; 0]; 1_000_000_000]                    : 30ns
vec![[[1u8; 0]; 1_000_000]; 1_000_000]                  : 20ns
vec![[[(); 37]; 1_000_000]; 1_000_000]                  : 20ns
vec![[[1u128; 0]; 1_000_000]; 1_000_000]                : 20ns
vec![(0u8, 0u16); 1_000_000_000]                        : 30ns
vec![0u32; 1_000_000_000]                               : 20ns
vec![[const { NonCopyZst }; 2]; 1_000]                  : 3.52µs
vec![NonCopyZst; 10_000]                                : 17.13µs
```
</details>

The specific expression I ran into a perf issue that this PR addresses is `vec![[(); LARGE]; LARGE]`, as I was trying to demonstrate `Vec::into_flattened` panicking on length overflow in the playground, but got a timeout error instead since `vec![[(); LARGE]; LARGE]` took so long to run in debug mode (it runs fine on the playground in release mode)
2025-11-11 02:44:37 +00:00
Nicholas Nethercote c6dbda8996 Document (and test) a problem with Clone/Copy deriving. 2025-11-11 11:35:10 +11:00
Tshepang Mbambo dbd05d336e Merge pull request #2638 from rust-lang/tshepang/sembr
sembr sanitizers.md and improve it a bit
2025-11-11 00:39:57 +02:00
Tshepang Mbambo de1b7754d1 some text improvements 2025-11-11 00:38:30 +02:00
Tshepang Mbambo 7675d7a1f0 sembr sanitizers.md 2025-11-11 00:27:59 +02:00
Tshepang Mbambo 191778d6cc Merge pull request #2637 from rust-lang/tshepang/sembr
sembr tests/running.md and improve it a bit
2025-11-11 00:13:59 +02:00
Tshepang Mbambo 6e14d2a7b1 a more suitable marker 2025-11-11 00:12:04 +02:00
Tshepang Mbambo 87c406469f fix code block language marker 2025-11-11 00:10:42 +02:00
Tshepang Mbambo 241e8909a0 tests/running.md: minor improvements 2025-11-11 00:08:31 +02:00
Tshepang Mbambo b271341781 sembr: handle text inside div blocks
The hackiness of this tool is getting more and more embarassing
2025-11-11 00:08:31 +02:00
Tshepang Mbambo 299a13b060 sembr tests/running.md 2025-11-10 23:36:16 +02:00
Tshepang Mbambo 2ae4b0bdad Merge pull request #2636 from rust-lang/tshepang/sembr
sembr getting-started.md and improve it a bit
2025-11-10 23:33:44 +02:00
Seth Junot 191a3e3c19 Noted the previous forced default in the change tracker 2025-11-10 13:32:39 -08:00
Tshepang Mbambo b4a91c396b a double dot is not end of sentence 2025-11-10 23:27:51 +02:00
Tshepang Mbambo 7a7608cd0e overlong 2025-11-10 23:27:51 +02:00
Tshepang Mbambo 49143e5be8 use chapter name instead of text that does not fit well 2025-11-10 23:27:51 +02:00
Tshepang Mbambo f4e2f0b10b sembr src/getting-started.md 2025-11-10 23:27:32 +02:00
Seth Junot a726de2305 bootstrap: respect build.python on macOS
The `python()` method was hardcoded to return `/usr/bin/python3` on
macOS, ignoring the `build.python` config option. This change respects
the config and removes the macOS-specific default.
2025-11-10 13:27:11 -08:00