allow deref patterns to move out of boxes
This adds a case to lower deref patterns on boxes using a built-in deref instead of a `Deref::deref` or `DerefMut::deref_mut` call: if `deref!(inner): Box<T>` is matching on place `place`, the inner pattern `inner` now matches on `*place` rather than a temporary. No longer needing to call a method also means it won't borrow the scrutinee in match arms. This allows for bindings in `inner` to move out of `*place`.
For comparison with box patterns, this uses the same MIR lowering but different THIR. Consequently, deref patterns on boxes are treated the same as any other deref patterns in match exhaustiveness analysis. Box patterns can't quite be implemented in terms of deref patterns until exhaustiveness checking for deref patterns is implemented (I'll open a PR for exhaustiveness soon!).
Tracking issue: #87121
r? ``@Nadrieril``
Rollup of 7 pull requests
Successful merges:
- #140056 (Fix a wrong error message in 2024 edition)
- #140220 (Fix detection of main function if there are expressions around it)
- #140249 (Remove `weak` alias terminology)
- #140316 (Introduce `BoxMarker` to improve pretty-printing correctness)
- #140347 (ci: clean more disk space in codebuild)
- #140349 (ci: use aws codebuild for the `dist-x86_64-linux` job)
- #140379 (rustc-dev-guide subtree update)
r? `@ghost`
`@rustbot` modify labels: rollup
Async drop codegen
Async drop implementation using templated coroutine for async drop glue generation.
Scopes changes to generate `async_drop_in_place()` awaits, when async droppable objects are out-of-scope in async context.
Implementation details:
https://github.com/azhogin/posts/blob/main/async-drop-impl.md
New fields in Drop terminator (drop & async_fut). Processing in codegen/miri must validate that those fields are empty (in full version async Drop terminator will be expanded at StateTransform pass or reverted to sync version). Changes in terminator visiting to consider possible new successor (drop field).
ResumedAfterDrop messages for panic when coroutine is resumed after it is started to be async drop'ed.
Lang item for generated coroutine for async function async_drop_in_place. `async fn async_drop_in_place<T>()::{{closure0}}`.
Scopes processing for generate async drop preparations. Async drop is a hidden Yield, so potentially async drops require the same dropline preparation as for Yield terminators.
Processing in StateTransform: async drops are expanded into yield-point. Generation of async drop of coroutine itself added.
Shims for AsyncDropGlueCtorShim, AsyncDropGlue and FutureDropPoll.
```rust
#[lang = "async_drop"]
pub trait AsyncDrop {
#[allow(async_fn_in_trait)]
async fn drop(self: Pin<&mut Self>);
}
impl Drop for Foo {
fn drop(&mut self) {
println!("Foo::drop({})", self.my_resource_handle);
}
}
impl AsyncDrop for Foo {
async fn drop(self: Pin<&mut Self>) {
println!("Foo::async drop({})", self.my_resource_handle);
}
}
```
First async drop glue implementation re-worked to use the same drop elaboration code as for sync drop.
`async_drop_in_place` changed to be `async fn`. So both `async_drop_in_place` ctor and produced coroutine have their lang items (`AsyncDropInPlace`/`AsyncDropInPlacePoll`) and shim instances (`AsyncDropGlueCtorShim`/`AsyncDropGlue`).
```
pub async unsafe fn async_drop_in_place<T: ?Sized>(_to_drop: *mut T) {
}
```
AsyncDropGlue shim generation uses `elaborate_drops::elaborate_drop` to produce drop ladder (in the similar way as for sync drop glue) and then `coroutine::StateTransform` to convert function into coroutine poll.
AsyncDropGlue coroutine's layout can't be calculated for generic T, it requires known final dropee type to be generated (in StateTransform). So, `templated coroutine` was introduced here (`templated_coroutine_layout(...)` etc).
Such approach overrides the first implementation using mixing language-level futures in https://github.com/rust-lang/rust/pull/121801.
Introduce `BoxMarker` to improve pretty-printing correctness
Box opening/closing is really easy to get wrong in the pretty-printers. This PR makes it much harder to get wrong.
r? `@Urgau`
Remove `weak` alias terminology
I find the "weak" alias terminology to be quite confusing. It implies the existence of "strong" aliases (which do not exist) and I'm not really sure what about weak aliases is "weak". I much prefer "free alias" as the term. I think it's much more obvious what it means as "free function" is a well defined term that already exists in rust.
It's also a little confusing given "weak alias" is already a term in linker/codegen spaces which are part of the compiler too. Though I'm not particularly worried about that as it's usually very obvious if you're talking about the type system or not lol. I'm also currently trying to write documentation about aliases and it's somewhat awkward/confusing to be talking about *weak* aliases, when I'm not really sure what the basis for that as the term actually *is*.
I would also be happy to just find out there's a nice meaning behind calling them "weak" aliases :-)
r? `@oli-obk`
maybe we want a types MCP to decide on a specific naming here? or maybe we think its just too late to go back on this naming decision ^^'
Fix detection of main function if there are expressions around it
Fixes#140162.
Fixes#139651.
Once this is merged, we can backport and I'll send a follow-up to emit a warning in case a `main` function is about to be "wrapped" (and therefore not run).
r? `@fmease`
try-job: x86_64-mingw-1
Implement a lint for implicit autoref of raw pointer dereference - take 2
*[t-lang nomination comment](https://github.com/rust-lang/rust/pull/123239#issuecomment-2727551097)*
This PR aims at implementing a lint for implicit autoref of raw pointer dereference, it is based on #103735 with suggestion and improvements from https://github.com/rust-lang/rust/pull/103735#issuecomment-1370420305.
The goal is to catch cases like this, where the user probably doesn't realise it just created a reference.
```rust
pub struct Test {
data: [u8],
}
pub fn test_len(t: *const Test) -> usize {
unsafe { (*t).data.len() } // this calls <[T]>::len(&self)
}
```
Since #103735 already went 2 times through T-lang, where they T-lang ended-up asking for a more restricted version (which is what this PR does), I would prefer this PR to be reviewed first before re-nominating it for T-lang.
----
Compared to the PR it is as based on, this PR adds 3 restrictions on the outer most expression, which must either be:
1. A deref followed by any non-deref place projection (that intermediate deref will typically be auto-inserted)
2. A method call annotated with `#[rustc_no_implicit_refs]`.
3. A deref followed by a `addr_of!` or `addr_of_mut!`. See bottom of post for details.
There are several points that are not 100% clear to me when implementing the modifications:
- ~~"4. Any number of automatically inserted deref/derefmut calls." I as never able to trigger this. Am I missing something?~~ Fixed
- Are "index" and "field" enough?
----
cc `@JakobDegen` `@WaffleLapkin`
r? `@RalfJung`
try-job: dist-various-1
try-job: dist-various-2
The pretty-printers open and close "boxes" of text a lot. The open and
close operations must be matched. The matching is currently all implicit
and very easy to get wrong. (#140280 and #140246 are two recent
pretty-printing fixes that both involved unclosed boxes.)
This commit introduces `BoxMarker`, a marker type that represents an
open box. It makes box opening/closing explicit, which makes it much
easier to understand and harder to get wrong.
The commit also removes many comments are on `end` calls saying things
like "end outer head-block", "Close the outer-box". These demonstrate
how confusing the implicit approach was, but aren't necessary any more.
fix(test): Expose '--no-capture' in favor of `--nocapture`
This improves consistency with commonly expected CLI conventions,
avoiding a common stutter people make when running tests (trying what
they expect and then having to check the docs to then user whats
accepted).
An alternative could have been to take a value, like `--capture <value>` (e.g. `pytest` does this).
Overall, we're shifting focus for features to custom test harnesses (see #134283).
Most of `pytest`s modes will likely be irrelevant in that situation.
As for the rest, its too early to tell which, if any, may be relevant,
so we're sticking with this small, quality of life improvement.
I expect we'll warn about `--nocapture` being deprecated in the future after a sufficient transition period has been allowed.
By deprecating `--nocapture`, we intend that custom test harnesses do
not need to support it for reasons outside of their own compatibility
requirements, much like the deprecation in #134283
I'm punting for now on the naming of `RUST_TEST_NOCAPTURE`.
I feel like T-testing-devex should do a wider look at environment
variables role in lib`test` before evaluating whether to
- Deprecate it in favor of the user passing CLI flags or the test runner
providing its own config
- Deprecate in favor of `RUST_TEST_NO_CAPTURE`
- Deprecate in favor of `RUST_TEST_CAPTURE`
Other CLI flags were evaluated for casing consistency:
- `--logfile` has the same problem but was deprecated in #134283
Regarding the implementation, I moved `--nocapture` out of `optgroups()`, into `parse_opts()`, out of an abundance of caution in passing the options without a deprecated value to the usage generation. However, the usage does not actually show optional flags, so this could potentially be dropped, simplifying the PR.
Note: `compiletest` added `--no-capture` instead of `--nocapture` in #134809
T-testing-devex FCP: https://github.com/rust-lang/rust/issues/133073#issuecomment-2486921104Fixes#133073
Download GCC from CI on test builders
This should reduce the duration of the `x86_64-gnu-llvm-18` job, which runs on PR CI, which is currently the only one that builds GCC (outside of the x64 dist builder).
Since we handle the GCC download in the GCC step, and not eagerly in config, we can set this flag globally across all test builders, as it won't do anything unless they actually try to build GCC.
Opening as a draft to test if it works on CI, because I still need to implement logic to avoid the download if there are any local modifications to GCC (essentially the "if-unchanged" mode, although I want to try something a bit different).
r? ```@ghost```
Update lint-docs to default to Rust 2024
This updates the lint-docs tool to default to the 2024 edition. The lint docs are supposed to illustrate the code with the latest edition, and I just forgot to update this in https://github.com/rust-lang/rust/pull/133349.
Some docs needed to add the `edition` attribute since they were assuming a particular edition, but were missing the explicit annotation.
This also includes a commit to simplify the edition handling in lint-docs.
Correctly display stdout and stderr in case a doctest is failing
Fixes https://github.com/rust-lang/rust/issues/140289.
Since the doctest is actually running itself, we need to handle the output directly inside it.
cc `@fmease`
r? `@notriddle`
compiletest: Re-land using the new non-libtest executor by default
This PR re-lands #139998, which had the misfortune of triggering download-rustc in its CI jobs, so we didn't get proper test metrics for comparison with the old implementation. So that was PR was reverted in #140233, with the intention of re-landing it alongside a dummy compiler change to inhibit download-rustc.
---
Original PR description for #139998:
>The new executor was implemented in #139660, but required a manual opt-in. This PR activates the new executor by default, but leaves the old libtest-based executor in place (temporarily) to make reverting easier if something unexpectedly goes horribly wrong.
>
>Currently the new executor can be explicitly disabled by passing the `-N` flag to compiletest (e.g. `./x test ui -- -N`), but eventually that flag will be removed, alongside the removal of the libtest dependency. The flag is mostly there to make manual comparative testing easier if something does go wrong.
>
>As before, there *should* be no user-visible difference between the old executor and the new executor.
---
r? jieyouxu
This updates the lint-docs tool to default to the 2024 edition. The lint
docs are supposed to illustrate the code with the latest edition, and I
just forgot to update this in
https://github.com/rust-lang/rust/pull/133349.
Some docs needed to add the `edition` attribute since they were assuming
a particular edition, but were missing the explicit annotation.
This removes the hard-coded list of edition support in the lint-docs
tool, and instead just assumes the edition attribute is something valid.
There isn't a real reason to have this, as rustc will error if given a
wrong number. This should be easier to maintain going forward.
Update wasm-component-ld to 0.5.13
This commit updates the vendored `wasm-component-ld` binary to 0.5.13 which includes some various bug fixes and new feature updates for upcoming component model features coming down the pike. Not expected to break any existing workflows, just a normal update.
[compiletest] Parallelize test discovery
Certain filesystems are slow to service individual read requests, but can service many in parallel. This change brings down the time to run a single cached test on one of those filesystems from 40s to about 8s.
