don't encode only locally used attrs
Part of https://github.com/rust-lang/compiler-team/issues/505.
We now filter builtin attributes before encoding them in the crate metadata in case they should only be used in the local crate. To prevent accidental misuse `get_attrs` now requires the caller to state which attribute they are interested in. For places where that isn't trivially possible, I've added a method `fn get_attrs_unchecked` which I intend to remove in a followup PR.
After this pull request landed, we can then slowly move all attributes to only be used in the local crate while being certain that we don't accidentally try to access them from extern crates.
cc https://github.com/rust-lang/rust/pull/94963#issuecomment-1082924289
New lint: [`derive_partial_eq_without_eq`]
Introduces a new lint, [`derive_partial_eq_without_eq`].
See: #1781 (doesn't close it though).
changelog: add lint [`derive_partial_eq_without_eq`]
Replace `#[allow]` with `#[expect]` in Clippy
Hey `@rust-lang/clippy,` `@Alexendoo,` `@dswij,` I'm currently working on the expect attribute as defined in [Rust RFC 2383](https://rust-lang.github.io/rfcs/2383-lint-reasons.html). With that, an `#[allow]` attribute can be replaced with a `#[expect]` attribute that suppresses the lint, but also emits a warning, if the lint isn't emitted in the expected scope.
With this PR I would like to test the attribute on a project scale and Clippy obviously came to mind. This PR replaces (almost) all `#[allow]` attributes in `clippy_utils` and `clippy_lints` with the `#[expect]` attribute. I was also able to remove some allows since, the related FPs have been fixed 🎉.
My question is now, are there any concerns regarding this? It's still okay to add normal `#[allow]` attributes, I see the need to nit-pick about that in new PRs, unless it's actually a FP. Also, I would not recommend using `#[expect]` in tests, as changes to a lint could the trigger the expect attribute in other files.
Additionally, I've noticed that Clippy has a bunch of `#[allow(clippy::too_many_lines)]` attributes. Should we maybe allow the lint all together or increase the threshold setting? To me, it seems like we mostly just ignore it in our code. 😅🙃
---
changelog: none
r? `@flip1995` (I've requested you for now, since you're also helping with reviewing the expect implementation. You are welcome to delegate this PR, even if it should be a simple review 🙃 )
Recommend let chains over if_chain in docs
Switches over bit_mask.rs to let chains in order to create a nice example
While the rustfmt thing isn't resolved yet, my rust-analyzer isn't a fan of large `if_chains!`s, it stops giving me hover info and such after some number of if statements
changelog: none
Support tool lints with the `#[expect]` attribute (RFC 2383)
This PR fixes the ICE https://github.com/rust-lang/rust/issues/94953 by making the assert for converted expectation IDs conditional.
Additionally, it moves the lint expectation check into a separate query to support rustdoc and other tools. On the way, I've also added some tests to ensure that the attribute works for Clippy and rustdoc lints.
The number of changes comes from the long test file. This may look like a monster PR, this may smell like a monster PR and this may be a monster PR, but it's a harmless monster. 🦕
---
Closes: https://github.com/rust-lang/rust/issues/94953
cc: https://github.com/rust-lang/rust/issues/85549
r? `@wesleywiser`
cc: `@rust-lang/rustdoc`
Optionally allow `expect` and `unwrap` in tests
This addresses #1015, except it makes the new behavior optional.
The reason for the msrv-related changes is as follows.
Rather than expand `check_methods` list of arguments, it seemed easier to make `check_methods` a method of `Methods`, so that `check_methods` could access `Methods`' fields.
`check_methods` had an `msrv` parameter, which I consequently made a field of `Methods`. But, to avoid adding a lifetime parameter to `Methods`, I made the field type `Option<RustcVersion>` instead of the parameter's existing type, `Option<&RustcVersion>`. This seemed sensible since `RustcVersion` implements `Copy`. But this broke a lot of code that expected an `Option<&RustcVersion>` or `&Option<RustcVersion>`. I changed all of those occurrences to `Option<RustcVersion>`. IMHO, the code is better as a result of these changes, though.
The msrv-related changes are in their own commit to (hopefully) ease review.
Closes#1015
changelog: optionally allow `expect` and `unwrap` in tests
r? `@llogiq`
Track if a where bound comes from a impl Trait desugar
With https://github.com/rust-lang/rust/pull/93803 `impl Trait` function arguments get desugared to hidden where bounds. However, Clippy needs to know if a bound was originally a `impl Trait` or an actual bound. This adds a field to the `WhereBoundPredicate` struct to keep track of this information during AST->HIR lowering.
r? `@cjgillot`
cc `@estebank` (as the reviewer of #93803)
Create clippy lint against unexpectedly late drop for temporaries in match scrutinee expressions
A new clippy lint for issue 93883 (https://github.com/rust-lang/rust/issues/93883). Relies on a new trait in `marker` (called `SignificantDrop` to enable linting), which is why this PR is for the rust-lang repo and not the clippy repo.
changelog: new lint [`significant_drop_in_scrutinee`]
With #93803 `impl Trait` function arguments get desugared to hidden
where bounds. However, Clippy needs to know if a bound was originally a
impl Trait or an actual bound. This adds a field to the
`WhereBoundPredicate` struct to keep track of this information during
HIR lowering.
Address `unnecessary_to_owned` false positive
My proposed fix for #8759 is to revise the conditions that delineate `redundant_clone` and `unnecessary_to_owned`:
```rust
// Only flag cases satisfying at least one of the following three conditions:
// * the referent and receiver types are distinct
// * the referent/receiver type is a copyable array
// * the method is `Cow::into_owned`
// This restriction is to ensure there is no overlap between `redundant_clone` and this
// lint. It also avoids the following false positive:
// https://github.com/rust-lang/rust-clippy/issues/8759
// Arrays are a bit of a corner case. Non-copyable arrays are handled by
// `redundant_clone`, but copyable arrays are not.
```
This change causes a few cases that were previously flagged by `unnecessary_to_owned` to no longer be flagged. But one could argue those cases would be better handled by `redundant_clone`.
Closes#8759
changelog: none
Allow inline consts to reference generic params
Tracking issue: #76001
The RFC says that inline consts cannot reference to generic parameters (for now), same as array length expressions. And expresses that it's desirable for it to reference in-scope generics, when array length expressions gain that feature as well.
However it is possible to implement this for inline consts before doing this for all anon consts, because inline consts are only used as values and they won't be used in the type system. So we can have:
```rust
fn foo<T>() {
let x = [4i32; std::mem::size_of::<T>()]; // NOT ALLOWED (for now)
let x = const { std::mem::size_of::<T>() }; // ALLOWED with this PR!
let x = [4i32; const { std::mem::size_of::<T>() }]; // NOT ALLOWED (for now)
}
```
This would make inline consts super useful for compile-time checks and assertions:
```rust
fn assert_zst<T>() {
const { assert!(std::mem::size_of::<T>() == 0) };
}
```
This would create an error during monomorphization when `assert_zst` is instantiated with non-ZST `T`s. A error during mono might sound scary, but this is exactly what a "desugared" inline const would do:
```rust
fn assert_zst<T>() {
struct F<T>(T);
impl<T> F<T> {
const V: () = assert!(std::mem::size_of::<T>() == 0);
}
let _ = F::<T>::V;
}
```
It should also be noted that the current inline const implementation can already reference the type params via type inference, so this resolver-level restriction is not any useful either:
```rust
fn foo<T>() -> usize {
let (_, size): (PhantomData<T>, usize) = const {
const fn my_size_of<T>() -> (PhantomData<T>, usize) {
(PhantomData, std::mem::size_of::<T>())
}
my_size_of()
};
size
}
```
```@rustbot``` label: F-inline_const
Pass through extra args in `cargo dev lint`
changelog: Pass through extra args in `cargo dev lint`
Lets you pass some useful flags through, like `-A/W/etc`, `--fix`, `--force-warn`
