Split-up stability_index query
This PR aims to move deprecation and stability processing away from the monolithic `stability_index` query, and directly implement `lookup_{deprecation,stability,body_stability,const_stability}` queries.
The basic idea is to:
- move per-attribute sanity checks into `check_attr.rs`;
- move attribute compatibility checks into the `MissingStabilityAnnotations` visitor;
- progressively dismantle the `Annotator` visitor and the `stability_index` query.
The first commit contains functional change, and now warns when `#[automatically_derived]` is applied on a non-trait impl block. The other commits should not change visible behaviour.
Perf in https://github.com/rust-lang/rust/pull/143845#issuecomment-3066308630 shows small but consistent improvement, except for unused-warnings case. That case being a stress test, I'm leaning towards accepting the regression.
This PR changes `check_attr`, so has a high conflict rate on that file. This should not cause issues for review.
Rollup of 11 pull requests
Successful merges:
- rust-lang/rust#142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled)
- rust-lang/rust#143271 (Store the type of each GVN value)
- rust-lang/rust#143293 (fix `-Zsanitizer=kcfi` on `#[naked]` functions)
- rust-lang/rust#143719 (Emit warning when there is no space between `-o` and arg)
- rust-lang/rust#143846 (pass --gc-sections if -Zexport-executable-symbols is enabled and improve tests)
- rust-lang/rust#143891 (Port `#[coverage]` to the new attribute system)
- rust-lang/rust#143967 (constify `Option` methods)
- rust-lang/rust#144008 (Fix false positive double negations with macro invocation)
- rust-lang/rust#144010 (Boostrap: add warning on `optimize = false`)
- rust-lang/rust#144049 (rustc-dev-guide subtree update)
- rust-lang/rust#144056 (Copy GCC sources into the build directory even outside CI)
r? `@ghost`
`@rustbot` modify labels: rollup
Copy GCC sources into the build directory even outside CI
It takes ~3.5s on my Linux notebook to perform the copy, but it should only be executed when we actually go build GCC, and that will almost certainly take much longer :) So I think it should be fine. At least we won't be polluting the source directory for local builds.
Fixes: https://github.com/rust-lang/rust/issues/143986
r? `````@nikic`````
Boostrap: add warning on `optimize = false`
I recently came across a bug that can be traced back to the use of `optimize = false` in `bootstrap.toml` in combination with other settings. Following [this](https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/Missing.20box-related.20symbols.20with.20panic.20.3D.20'abort'/with/528992909) conversation, this PR adds a warning from `bootstrap` when `optimize = false` is used.
I notice that in the same file I edited there are two different styles for warnings (`WARN`, `Warning`). I used `WARNING` because, by happenstance, when testing I got a `WARNING` that I didn't set a change id: let me know if I can unify the styles in the file I edited.
fix `-Zsanitizer=kcfi` on `#[naked]` functions
fixes https://github.com/rust-lang/rust/issues/143266
With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call).
My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`.
r? codegen
````@rustbot```` label +A-naked
cc ````@maurer```` ````@rcvalle````
`-Zhigher-ranked-assumptions`: Consider WF of coroutine witness when proving outlives assumptions
### TL;DR
This PR introduces an unstable flag `-Zhigher-ranked-assumptions` which tests out a new algorithm for dealing with some of the higher-ranked outlives problems that come from auto trait bounds on coroutines. See:
* rust-lang/rust#110338
While it doesn't fix all of the issues, it certainly fixed many of them, so I'd like to get this landed so people can test the flag on their own code.
### Background
Consider, for example:
```rust
use std::future::Future;
trait Client {
type Connecting<'a>: Future + Send
where
Self: 'a;
fn connect(&self) -> Self::Connecting<'_>;
}
fn call_connect<C>(c: C) -> impl Future + Send
where
C: Client + Send + Sync,
{
async move { c.connect().await }
}
```
Due to the fact that we erase the lifetimes in a coroutine, we can think of the interior type of the async block as something like: `exists<'r, 's> { C, &'r C, C::Connecting<'s> }`. The first field is the `c` we capture, the second is the auto-ref that we perform on the call to `.connect()`, and the third is the resulting future we're awaiting at the first and only await point. Note that every region is uniquified differently in the interior types.
For the async block to be `Send`, we must prove that both of the interior types are `Send`. First, we have an `exists<'r, 's>` binder, which needs to be instantiated universally since we treat the regions in this binder as *unknown*[^exist]. This gives us two types: `{ &'!r C, C::Connecting<'!s> }`. Proving `&'!r C: Send` is easy due to a [`Send`](https://doc.rust-lang.org/nightly/std/marker/trait.Send.html#impl-Send-for-%26T) impl for references.
Proving `C::Connecting<'!s>: Send` can only be done via the item bound, which then requires `C: '!s` to hold (due to the `where Self: 'a` on the associated type definition). Unfortunately, we don't know that `C: '!s` since we stripped away any relationship between the interior type and the param `C`. This leads to a bogus borrow checker error today!
### Approach
Coroutine interiors are well-formed by virtue of them being borrow-checked, as long as their callers are invoking their parent functions in a well-formed way, then substitutions should also be well-formed. Therefore, in our example above, we should be able to deduce the assumption that `C: '!s` holds from the well-formedness of the interior type `C::Connecting<'!s>`.
This PR introduces the notion of *coroutine assumptions*, which are the outlives assumptions that we can assume hold due to the well-formedness of a coroutine's interior types. These are computed alongside the coroutine types in the `CoroutineWitnessTypes` struct. When we instantiate the binder when proving an auto trait for a coroutine, we instantiate the `CoroutineWitnessTypes` and stash these newly instantiated assumptions in the region storage in the `InferCtxt`. Later on in lexical region resolution or MIR borrowck, we use these registered assumptions to discharge any placeholder outlives obligations that we would otherwise not be able to prove.
### How well does it work?
I've added a ton of tests of different reported situations that users have shared on issues like rust-lang/rust#110338, and an (anecdotally) large number of those examples end up working straight out of the box! Some limitations are described below.
### How badly does it not work?
The behavior today is quite rudimentary, since we currently discharge the placeholder assumptions pretty early in region resolution. This manifests itself as some limitations on the code that we accept.
For example, `tests/ui/async-await/higher-ranked-auto-trait-11.rs` continues to fail. In that test, we must prove that a placeholder is equal to a universal for a param-env candidate to hold when proving an auto trait, e.g. `'!1 = 'a` is required to prove `T: Trait<'!1>` in a param-env that has `T: Trait<'a>`. Unfortunately, at that point in the MIR body, we only know that the placeholder is equal to some body-local existential NLL var `'?2`, which only gets equated to the universal `'a` when being stored into the return local later on in MIR borrowck.
This could be fixed by integrating these assumptions into the type outlives machinery in a more first-class way, and delaying things to the end of MIR typeck when we know the full relationship between existential and universal NLL vars. Doing this integration today is quite difficult today.
`tests/ui/async-await/higher-ranked-auto-trait-11.rs` fails because we don't compute the full transitive outlives relations between placeholders. In that test, we have in our region assumptions that some `'!1 = '!2` and `'!2 = '!3`, but we must prove `'!1 = '!3`.
This can be fixed by computing the set of coroutine outlives assumptions in a more transitive way, or as I mentioned above, integrating these assumptions into the type outlives machinery in a more first-class way, since it's already responsible for the transitive outlives assumptions of universals.
### Moving forward
I'm still quite happy with this implementation, and I'd like to land it for testing. I may work on overhauling both the way we compute these coroutine assumptions and also how we deal with the assumptions during (lexical/nll) region checking. But for now, I'd like to give users a chance to try out this new `-Zhigher-ranked-assumptions` flag to uncover more shortcomings.
[^exist]: Instantiating this binder with infer regions would be incomplete, since we'd be asking for *some* instantiation of the interior types, not proving something for *all* instantiations of the interior types.
* `examples/minimal_lsp.rs` – compact LSP server showing definition,
completion, hover, rustfmt-based formatting, and dummy diagnostics.
Advertises UTF-8 offset encoding.
* `examples/manual_test.sh` – FIFO script that streams the canonical
nine LSP packets so anyone can validate the server from two terminals.
No new runtime deps; `anyhow` stays under [dev-dependencies].
Make frame spans appear on a separate trace line
This PR changes tracing_chrome's `tracing::Layer` so that if a span has the "tracing_separate_line" field as one of the span arguments, that span is put on a separate trace line. See https://github.com/rust-lang/miri/pull/4451 for an earlier attempt and for screenshots explaining better what I mean by "separate trace line".
This PR also makes the "frame" span use this feature (so it appears on a separate trace line, see https://github.com/rust-lang/miri/pull/4451 for motivation), but passes `tracing::field::Empty` as the span parameter value so it is ignored by other tracing layers (e.g. the logger):
```rust
info_span!("frame", tracing_separate_line = Empty, "{}", instance);
```
<details><summary>Also see the following discussion I had with ``@RalfJung</summary>``
> Is there no way to attach metadata we could use instead?
[These](https://docs.rs/tracing-core/0.1.34/src/tracing_core/metadata.rs.html#57) are the **static** metadata items we can control about a span. We can't add more metadata outside of them. The most relevant are:
- `name` (for the frame span it's currently "frame")
- `target` which acts as the category (for the frame span it's currently "rustc_const_eval::interpret::stack" by default)
- `fields` which contains a list of the *names* of each of the arguments passed to the `span!` macro (for the frame span it's currently ["message"], where "message" is the default identifier for data passed in the `format!` syntax)
When the tracing code is called at runtime, the **dynamic** values of the arguments are collected into a [`ValueSet`](https://docs.rs/tracing-core/0.1.34/src/tracing_core/field.rs.html#166). Each argument value stored there corresponds with one of the static names stored in `fields` (see above).
---
We have already determined that filtering out spans by `name` is not a good idea, and I would say the same goes for `target`. Both the `name` and the `target` fields are printed to stderr when `MIRI_LOG=` is enabled, so changing them to contain an identifier (e.g. "frame:tracing_separate_root" instead of "frame" as the name) would uselessly clutter the text logs (unless we add one more filter [there](https://github.com/rust-lang/rust/blob/master/compiler/rustc_log/src/lib.rs#L137), but then it gets even more complicated).
```rust
// examples of how the above (problematic) solutions would look like
info_span!("frame:tracing_separate_root", "{}", instance);
info_span!(target: "tracing_separate_root", "frame", "{}", instance);
```
---
So that leaves us with `fields` and their runtime values. Now, my initial thought (inspired by [this comment](https://github.com/rust-lang/miri/pull/4451#issuecomment-3068072303)) was to use a field with the static name "tracing_separate_root" and with a dynamic boolean value of "true". In `tracing_chrome.rs` we can easily check if this field is true and act accordingly. This would work but then again this field would also be picked up by the logger when `MIRI_LOG=` is enabled, and would uselessly clutter the text logs.
```rust
// example of how the above (problematic) solution would look like
info_span!("frame", tracing_separate_root = true, "{}", instance);
```
---
To avoid cluttering the text logs, we can instead set "tracing_separate_root" to the dynamic value of `tracing::field::Empty`. Citing from [here](https://docs.rs/tracing/0.1.41/tracing/field/struct.Empty.html), "when a field’s value is `Empty`, it will not be recorded". "not being recorded" means that the field and its value won't be printed to stderr text logs, nor will it be printed by any other tracing layers that might be attached in the future. In `tracing_chrome.rs` we would still be able to check if "tracing_separate_root" is in the list of static `fields`, and act accordingly. So I believe this solution would effectively allow us to attach metadata to a span in a way that does not clutter logs and still allows being read in `tracing_chrome.rs`.
If we ever wanted to pass arbitrary metadata (i.e. not just a present/not present flag), it would be possible with a custom `Empty` that also holds data and implement `Value` without doing anything ([like `Empty` does](https://docs.rs/tracing-core/0.1.34/src/tracing_core/field.rs.html#775)).
```rust
// example of how the above solution would look like
info_span!("frame", tracing_separate_root = tracing::field::Empty, "{}", instance);
```
</details>
Reword mismatched-lifetime-syntaxes text based on feedback
Key changes include:
- Removal of the word "syntax" from the lint message. More accurately, it could have been something like "syntax group" or "syntax category", but avoiding it completely is easier.
- The primary lint message now reflects exactly which mismatch is occurring, instead of trying to be general. A new `help` line is general across the mismatch kinds.
- Suggestions have been reduced to be more minimal, no longer also changing non-idiomatic but unrelated aspects.
- Suggestion text no longer mentions changes when those changes don't occur in that specific suggestion.
r? ``@jieyouxu``
update to literal-escaper-0.0.5
Quoting from the changelog, this version brings:
- Use `NonZero<char/u8>` in `unescape_c_str` and `check_raw_c_str` to statically exclude nuls
- Add `#[inline]` to small functions for improved performance
Fix handling of SCRIPT_ARG in docker images
Instead of making this a build parameter, pass the SCRIPT as an environment variable.
To this purpose, normalize on always referring to a script in `/scripts`.
For i686-gnu-nopt-2 I had to create a separate script, because Docker seems to be really terrible at command line argument parsing, so it's not possible to pass an environment variable that contains whitespace.
Fixes https://github.com/rust-lang/rust/issues/143962.
try-job: `dist-x86_64-linux`
try-job: `i686-gnu-nopt-*`
try-job: `i686-gnu-*`
try-job: `x86_64-gnu-llvm-19-*`
try-job: `x86_64-gnu-llvm-20-*`
ci cleanup: rustdoc-gui-test now installs browser-ui-test
this removes the need for --unsafe-perm in the Dockerfile.
cc ```@GuillaumeGomez``` ```@Kobzol```
Implement unstable trait impl
This PR allows marking impls of stable trait with stable type as unstable.
## Approach
In std/core, an impl can be marked as unstable by annotating it with ``#[unstable_feature_bound(feat_name)]``. This will add a ``ClauseKind::Unstable_Feature(feat_name)`` to the list of predicates in ``predicates_of`` .
When an unstable impl's function is called, we will first iterate through all the goals in ``param_env`` to check if there is any ``ClauseKind::UnstableFeature(feat_name)`` in ``param_env``.
The existence of ``ClauseKind::Unstable_Feature(feat_name)`` in ``param_env`` means an``#[unstable_feature_bound(feat_name)]`` is present at the call site of the function, so we allow the check to succeed in this case.
If ``ClauseKind::UnstableFeature(feat_name)`` does not exist in ``param_env``, we will still allow the check to succeed for either of the cases below:
1. The feature is enabled through ``#[feature(feat_name)]`` outside of std / core.
2. We are in codegen because we may be monomorphizing a body from an upstream crate which had an unstable feature enabled that the downstream crate do not.
For the rest of the case, it will fail with ambiguity.
## Limitation
In this PR, we do not support:
1. using items that need ``#[unstable_feature_bound]`` within stable APIs
2. annotate main function with ``#[unstable_feature_bound]``
3. annotate ``#[unstable_feature_bound]`` on items other than free function and impl
## Acknowledgement
The design and mentoring are done by `@BoxyUwU`
There are many places that join path segments with `::` to produce a
string. A lot of these use `join("::")`. Many in rustdoc use
`join_with_double_colon`, and a few use `.joined("..")`. One in Clippy
uses `itertools::join`. A couple of them look for `kw::PathRoot` in the
first segment, which can be important.
This commit introduces `rustc_ast::join_path_{syms,ident}` to do the
joining for everyone. `rustc_ast` is as good a location for these as
any, being the earliest-running of the several crates with a `Path`
type. Two functions are needed because `Ident` printing is more complex
than simple `Symbol` printing.
The commit also removes `join_with_double_colon`, and
`estimate_item_path_byte_length` with it.
There are still a handful of places that join strings with "::" that are
unchanged. They are not that important: some of them are in tests, and
some of them first split a path around "::" and then rejoin with "::".
This fixes one test case where `{{root}}` shows up in an error message.
