Skip `if-let-rescope` lint unless requested by migration
Tracked by #124085
Related to https://github.com/rust-lang/rust/pull/131984#issuecomment-2448329667
Given that `if-let-rescope` is a lint to be enabled globally by an edition migration, there is no point in extracting the precise lint level on the HIR expression. This mitigates the performance regression discovered by the earlier perf-run.
cc `@Kobzol` `@rylev` `@traviscross` I propose a `rust-timer` run to measure how much performance that we can recover from the mitigation. 🙇
The limit was introduced in https://github.com/rust-lang/rust-analyzer/pull/1408#discussion_r294059044 to avoid infinite cycles but it effectively caps the number of derefs to 10. Types like `ID3D12Device14` from the `windows` crate run into this because it derefs to `ID3D12Device13`, 13 to 12 and so on. Increasing it to 20 is a quick fix; a better cycle detection method would be nicer long term.
Properly record metavar spans for other expansions other than TT
This properly records metavar spans for nonterminals other than tokentree. This means that we operations like `span.to(other_span)` work correctly for macros. As you can see, other diagnostics involving metavars have improved as a result.
Fixes#132908
Alternative to #133270
cc `@ehuss`
cc `@petrochenkov`
Update our range `assume`s to the format that LLVM prefers
I found out in https://github.com/llvm/llvm-project/issues/123278#issuecomment-2597440158 that the way I started emitting the `assume`s in #109993 was suboptimal, and as seen in that LLVM issue the way we're doing it -- with two `assume`s sometimes -- can at times lead to CVP/SCCP not realize what's happening because one of them turns into a `ne` instead of conveying a range.
So this updates how it's emitted from
```
assume( x >= LOW );
assume( x <= HIGH );
```
or
```
// (for ranges that wrap the range)
assume( (x <= LOW) | (x >= HIGH) );
```
to
```
assume( (x - LOW) <= (HIGH - LOW) );
```
so that we don't need multiple `icmp`s nor multiple `assume`s for a single value, and both wrappping and non-wrapping ranges emit the same shape.
(And we don't bother emitting the subtraction if `LOW` is zero, since that's trivial for us to check too.)
Ensure that all the fields that rust-analyzer understands are in the
manual, they all have doc comments, and they use consistent
punctuation (`;` rather than mixing `,` and `;`).
Whilst we're here, fix the `sysroot_src` example and add 2024 as a
legal value for Rust edition.
remove support for the (unstable) #[start] attribute
As explained by `@Noratrieb:`
`#[start]` should be deleted. It's nothing but an accidentally leaked implementation detail that's a not very useful mix between "portable" entrypoint logic and bad abstraction.
I think the way the stable user-facing entrypoint should work (and works today on stable) is pretty simple:
- `std`-using cross-platform programs should use `fn main()`. the compiler, together with `std`, will then ensure that code ends up at `main` (by having a platform-specific entrypoint that gets directed through `lang_start` in `std` to `main` - but that's just an implementation detail)
- `no_std` platform-specific programs should use `#![no_main]` and define their own platform-specific entrypoint symbol with `#[no_mangle]`, like `main`, `_start`, `WinMain` or `my_embedded_platform_wants_to_start_here`. most of them only support a single platform anyways, and need cfg for the different platform's ways of passing arguments or other things *anyways*
`#[start]` is in a super weird position of being neither of those two. It tries to pretend that it's cross-platform, but its signature is a total lie. Those arguments are just stubbed out to zero on ~~Windows~~ wasm, for example. It also only handles the platform-specific entrypoints for a few platforms that are supported by `std`, like Windows or Unix-likes. `my_embedded_platform_wants_to_start_here` can't use it, and neither could a libc-less Linux program.
So we have an attribute that only works in some cases anyways, that has a signature that's a total lie (and a signature that, as I might want to add, has changed recently, and that I definitely would not be comfortable giving *any* stability guarantees on), and where there's a pretty easy way to get things working without it in the first place.
Note that this feature has **not** been RFCed in the first place.
*This comment was posted [in May](https://github.com/rust-lang/rust/issues/29633#issuecomment-2088596042) and so far nobody spoke up in that issue with a usecase that would require keeping the attribute.*
Closes https://github.com/rust-lang/rust/issues/29633
try-job: x86_64-gnu-nopt
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
try-job: test-various
If the user doesn't have rustc on $PATH, rust-analyzer won't be able
to run `rustc --print cfg`. This isn't really an error, as
rust-analyzer can still proceed without it.
This is particularly noticeable when loading crates defined in a
rust-project.json. Until the configuration is loaded, the opened files
are briefly treated as detached files and users see this error.
Environments with rust-project.json generally have a sysroot and rustc
elsewhere, so the error confuses users.
Rework dyn trait lowering to stop being so intertwined with trait alias expansion
This PR reworks the trait object lowering code to stop handling trait aliases so funky, and removes the `TraitAliasExpander` in favor of a much simpler design. This refactoring is important for making the code that I'm writing in https://github.com/rust-lang/rust/pull/133397 understandable and easy to maintain, so the diagnostics regressions are IMO inevitable.
In the old trait object lowering code, we used to be a bit sloppy with the lists of traits in their unexpanded and expanded forms. This PR largely rewrites this logic to expand the trait aliases *once* and handle them more responsibly throughout afterwards.
Please review this with whitespace disabled.
r? lcnr
Enable `unreachable_pub` lint in core
This PR enables the [`unreachable_pub`](https://doc.rust-lang.org/rustc/lints/listing/allowed-by-default.html#unreachable-pub) as warn in `core`, `rtstartup` and `panic_unwind`.
The motivation is similar to the compiler [MCP: Enable deny(unreachable_pub) on `rustc_*` crates](https://github.com/rust-lang/compiler-team/issues/773#issue-2467219005) :
> "Where is this thing used?" is a question I ask all the time when reading unfamiliar code. Because of this, I generally find it annoying when things are marked with a more permissive visibility than necessary. "This thing marked pub, which other crates is it used in? Oh, it's not used in any other crates."
Another motivation is to help to lint by utilizing it in-tree and seeing it's limitation in more complex scenarios.
The diff was mostly generated with `./x.py fix --stage 1 library/core/ -- --broken-code`, as well as manual edits for code in macros, generated code and other targets.
r? libs
Subtree sync for rustc_codegen_cranelift
Nothing too exciting this time, but this includes a fix for a linker hang on Windows: https://github.com/rust-lang/rustc_codegen_cranelift/pull/1554
r? ``@ghost``
``@rustbot`` label +A-codegen +A-cranelift +T-compiler
Partial progress on #132735: Replace extern "rust-intrinsic" with #[rustc_intrinsic] across the codebase
Part of #132735: Replace `extern "rust-intrinsic"` with `#[rustc_intrinsic]` macro
- Updated all instances of `extern "rust-intrinsic"` to use the `#[rustc_intrinsic]` macro.
- Skipped `.md` files and test files to avoid unnecessary changes.
Reexport likely/unlikely in std::hint
Since `likely`/`unlikely` should be working now, we could reexport them in `std::hint`. I'm not sure if this is already approved or if it requires approval
Tracking issue: #26179
This time, when completing the keyword (e.g. `fn` + whitespace).
The bug was actually a double-bug:
First, we did not resolve the impl in the macro-expanded file but in the real file, which of course cannot work.
Second, in analysis the whitespace was correlated with the `impl` and not the incomplete `fn`, which caused fake (where we insert an identifier after the whitespace) and real expansions to go out of sync, which failed analysis. The fix is to skip whitespaces in analysis.
