Fix ICE: Restrict param constraint suggestion
When encountering an associated item with a type param that could be constrained, do not look at the parent item if the type param comes from the associated item.
Fix#117209, fix#89868.
Properly restore snapshot when failing to recover parsing ternary
If the recovery parsed an expression, then failed to eat a `:`, it would return `false` without restoring the snapshot. Fix this by always restoring the snapshot when returning `false`.
Draft for now because I'd like to try and improve this recovery further.
Fixes#117208
```
error[E0277]: the trait bound `S: d::Hidden` is not satisfied
--> $DIR/sealed-trait-local.rs:53:20
|
LL | impl c::Sealed for S {}
| ^ the trait `d::Hidden` is not implemented for `S`
|
note: required by a bound in `c::Sealed`
--> $DIR/sealed-trait-local.rs:17:23
|
LL | pub trait Sealed: self::d::Hidden {
| ^^^^^^^^^^^^^^^ required by this bound in `Sealed`
= note: `Sealed` is a "sealed trait", because to implement it you also need to implement `c::d::Hidden`, which is not accessible; this is usually done to force you to use one of the provided types that already implement it
= help: the following types implement the trait:
- c::X
- c::Y
```
The last `help` is new.
When encountering
```rust
foo()
*bar = baz;
```
We currently emit potentially two errors, one for the return type of
`foo` not being multiplyiable by the type of `bar`, and another for
`foo() * bar` not being assignable.
We now check for this case and suggest adding a semicolon in the right
place.
Fix#80446.
Lint overlapping ranges as a separate pass
This reworks the [`overlapping_range_endpoints`](https://doc.rust-lang.org/beta/nightly-rustc/rustc_lint_defs/builtin/static.OVERLAPPING_RANGE_ENDPOINTS.html) lint. My motivations are:
- It was annoying to have this lint entangled with the exhaustiveness algorithm, especially wrt librarification;
- This makes the lint behave consistently.
Here's the consistency story. Take the following matches:
```rust
match (0u8, true) {
(0..=10, true) => {}
(10..20, true) => {}
(10..20, false) => {}
_ => {}
}
match (true, 0u8) {
(true, 0..=10) => {}
(true, 10..20) => {}
(false, 10..20) => {}
_ => {}
}
```
There are two semantically consistent options: option 1 we lint all overlaps between the ranges, option 2 we only lint the overlaps that could actually occur (i.e. the ones with `true`). Option 1 is what this PR does. Option 2 is possible but would require the exhaustiveness algorithm to track more things for the sake of the lint. The status quo is that we're inconsistent between the two.
Option 1 generates more false postives, but I prefer it from a maintainer's perspective. I do think the difference is minimal; cases where the difference is observable seem rare.
This PR adds a separate pass, so this will have a perf impact. Let's see how bad, it looked ok locally.
notes
This commit extends the `#[diagnostic::on_unimplemented]` (and
`#[rustc_on_unimplemented]`) attributes to allow multiple `note`
options. This enables emitting multiple notes for custom error messages.
For now I've opted to not change any of the existing usages of
`#[rustc_on_unimplemented]` and just updated the relevant compile tests.
Rollup of 6 pull requests
Successful merges:
- #114998 (feat(docs): add cargo-pgo to PGO documentation 📝)
- #116868 (Tweak suggestion span for outer attr and point at item following invalid inner attr)
- #117240 (Fix documentation typo in std::iter::Iterator::collect_into)
- #117241 (Stash and cancel cycle errors for auto trait leakage in opaques)
- #117262 (Create a new ConstantKind variant (ZeroSized) for StableMIR)
- #117266 (replace transmute by raw pointer cast)
r? `@ghost`
`@rustbot` modify labels: rollup
Stash and cancel cycle errors for auto trait leakage in opaques
We don't need to emit a traditional cycle error when we have a selection error that explains what's going on but in more detail.
We may want to augment this error to actually point out the cycle, now that the cycle error is not being emitted. We could do that by storing the set of opaques that was in the `CyclePlaceholder` that gets returned from `type_of_opaque`.
r? `@oli-obk` cc `@estebank` #117235
Refactor some `char`, `u8` ASCII functions to be branchless
Extract conditions in singular `matches!` with or-patterns to individual `matches!` statements which enables branchless code output. The following functions were changed:
- `is_ascii_alphanumeric`
- `is_ascii_hexdigit`
- `is_ascii_punctuation`
Added codegen tests
---
Continued from https://github.com/rust-lang/rust/pull/103024.
Based on the comment from `@scottmcm` https://github.com/rust-lang/rust/pull/103024#pullrequestreview-1248697206.
The unmodified `is_ascii_*` functions didn't seem to benefit from extracting the conditions.
I've never written a codegen test before, but I tried to check that no branches were emitted.
Allow target specs to use an LLD flavor, and self-contained linking components
This PR allows:
- target specs to use an LLD linker-flavor: this is needed to switch `x86_64-unknown-linux-gnu` to using LLD, and is currently not possible because the current flavor json serialization fails to roundtrip on the modern linker-flavors. This can e.g. be seen in https://github.com/rust-lang/rust/pull/115622#discussion_r1321312880 which explains where an `Lld::Yes` is ultimately deserialized into an `Lld::No`.
- target specs to declare self-contained linking components: this is needed to switch `x86_64-unknown-linux-gnu` to using `rust-lld`
- adds an end-to-end test of a custom target json simulating `x86_64-unknown-linux-gnu` being switched to using `rust-lld`
- disables codegen backends from participating because they don't support `-Zgcc-ld=lld` which is the basis of mcp510.
r? `@petrochenkov:` if the approach discussed https://github.com/rust-lang/rust/pull/115622#discussion_r1329403467 and on zulip would work for you: basically, see if we can emit only modern linker flavors in the json specs, but accept both old and new flavors while reading them, to fix the roundtrip issue.
The backwards compatible `LinkSelfContainedDefault` variants are still serialized and deserialized in `crt-objects-fallback`, while the spec equivalent of e.g. `-Clink-self-contained=+linker` is serialized into a different json object (with future-proofing to incorporate `crt-objects-fallback` in the future).
---
I've been test-driving this in https://github.com/rust-lang/rust/pull/113382 to test actually switching `x86_64-unknown-linux-gnu` to `rust-lld` (and fix what needs to be fixed in CI, bootstrap, etc), and it seems to work fine.
Decompose singular `matches!` with or-patterns to individual `matches!`
statements to enable branchless code output. The following functions
were changed:
- `is_ascii_alphanumeric`
- `is_ascii_hexdigit`
- `is_ascii_punctuation`
Add codegen tests
Co-authored-by: George Bateman <george.bateman16@gmail.com>
Co-authored-by: scottmcm <scottmcm@users.noreply.github.com>
When expecting closure argument but finding block provide suggestion
Detect if there is a potential typo where the `{` meant to open the closure body was written before the body.
```
error[E0277]: expected a `FnOnce<({integer},)>` closure, found `Option<usize>`
--> $DIR/ruby_style_closure_successful_parse.rs:3:31
|
LL | let p = Some(45).and_then({|x|
| ______________________--------_^
| | |
| | required by a bound introduced by this call
LL | | 1 + 1;
LL | | Some(x * 2)
| | ----------- this tail expression is of type `Option<usize>`
LL | | });
| |_____^ expected an `FnOnce<({integer},)>` closure, found `Option<usize>`
|
= help: the trait `FnOnce<({integer},)>` is not implemented for `Option<usize>`
note: required by a bound in `Option::<T>::and_then`
--> $SRC_DIR/core/src/option.rs:LL:COL
help: you might have meant to open the closure body instead of placing a closure within a block
|
LL - let p = Some(45).and_then({|x|
LL + let p = Some(45).and_then(|x| {
|
```
Detect the potential typo where the closure header is missing.
```
error[E0277]: expected a `FnOnce<(&bool,)>` closure, found `bool`
--> $DIR/block_instead_of_closure_in_arg.rs:3:23
|
LL | Some(true).filter({
| _________________------_^
| | |
| | required by a bound introduced by this call
LL | |/ if number % 2 == 0 {
LL | || number == 0
LL | || } else {
LL | || number != 0
LL | || }
| ||_________- this tail expression is of type `bool`
LL | | });
| |______^ expected an `FnOnce<(&bool,)>` closure, found `bool`
|
= help: the trait `for<'a> FnOnce<(&'a bool,)>` is not implemented for `bool`
note: required by a bound in `Option::<T>::filter`
--> $SRC_DIR/core/src/option.rs:LL:COL
help: you might have meant to create the closure instead of a block
|
LL | Some(true).filter(|_| {
| +++
```
Partially address #27300. Fix#104690.
When encountering an associated item with a type param that could be
constrained, do not look at the parent item if the type param comes from
the associated item.
Fix#117209.
Rollup of 8 pull requests
Successful merges:
- #116905 (refactor(compiler/resolve): simplify some code)
- #117095 (Add way to differentiate argument locals from other locals in Stable MIR)
- #117143 (Avoid unbounded O(n^2) when parsing nested type args)
- #117194 (Minor improvements to `rustc_incremental`)
- #117202 (Revert "Remove TaKO8Ki from reviewers")
- #117207 (The value of `-Cinstrument-coverage=` doesn't need to be `Option`)
- #117214 (Quietly fail if an error has already occurred)
- #117221 (Rename type flag `HAS_TY_GENERATOR` to `HAS_TY_COROUTINE`)
r? `@ghost`
`@rustbot` modify labels: rollup
Add way to differentiate argument locals from other locals in Stable MIR
This PR resolvesrust-lang/project-stable-mir#47 which request a way to differentiate argument locals in a SMIR `Body` from other locals.
Specifically, this PR exposes the `arg_count` field from the MIR `Body`. However, I'm opening this as a draft PR because I think there are a few outstanding questions on how this information should be exposed and described. Namely:
- Is exposing `arg_count` the best way to surface this information to SMIR users? Would it be better to leave `arg_count` as a private field and add public methods (e.g. `fn arguments(&self) -> Iter<'_, LocalDecls>`) that may use the underlying `arg_count` info from the MIR body, but expose this information to users in a more convenient form? Or is it best to stick close to the current MIR convention?
- If the answer to the above point is to stick with the current MIR convention (`arg_count`), is it reasonable to also commit to sticking to the current MIR convention that the first local is always the return local, while the next `arg_count` locals are always the (in-order) argument locals?
- Should `Body` in SMIR only represent function bodies (as implied by the comment I added)? That seems to be the current case in MIR, but should this restriction always be the case for SMIR?
r? `@celinval`
r? `@oli-obk`
Never consider raw pointer casts to be trival
HIR typeck tries to figure out which casts are trivial by doing them as
coercions and seeing whether this works. Since HIR typeck is oblivious
of lifetimes, this doesn't work for pointer casts that only change the
lifetime of the pointee, which are, as borrowck will tell you, not
trivial.
This change makes it so that raw pointer casts are never considered
trivial.
This also incidentally fixes the "trivial cast" lint false positive on
the same code. Unfortunately, "trivial cast" lints are now never emitted
on raw pointer casts, even if they truly are trivial. This could be
fixed by also doing the lint in borrowck for raw pointers specifically.
fixes#113257
Rework negative coherence to properly consider impls that only partly overlap
This PR implements a modified negative coherence that handles impls that only have partial overlap.
It does this by:
1. taking both impl trait refs, instantiating them with infer vars
2. equating both trait refs
3. taking the equated trait ref (which represents the two impls' intersection), and resolving any vars
4. plugging all remaining infer vars with placeholder types
these placeholder-plugged trait refs can then be used normally with the new trait solver, since we no longer have to worry about the issue with infer vars in param-envs.
We use the **new trait solver** to reason correctly about unnormalized trait refs (due to deferred projection equality), since this avoid having to normalize anything under param-envs with infer vars in them.
This PR then additionally:
* removes the `FnPtr` knowable hack by implementing proper negative `FnPtr` trait bounds for rigid types.
---
An example:
Consider these two partially overlapping impls:
```
impl<T, U> PartialEq<&U> for &T where T: PartialEq<U> {}
impl<F> PartialEq<F> for F where F: FnPtr {}
```
Under the old algorithm, we would take one of these impls and replace it with infer vars, then try unifying it with the other impl under identity substitutions. This is not possible in either direction, since it either sets `T = U`, or tries to equate `F = &?0`.
Under the new algorithm, we try to unify `?0: PartialEq<?0>` with `&?1: PartialEq<&?2>`. This gives us `?0 = &?1 = &?2` and thus `?1 = ?2`. The intersection of these two trait refs therefore looks like: `&?1: PartialEq<&?1>`. After plugging this with placeholders, we get a trait ref that looks like `&!0: PartialEq<&!0>`, with the first impl having substs `?T = ?U = !0` and the second having substs `?F = &!0`[^1].
Then we can take the param-env from the first impl, and try to prove the negated where clause of the second.
We know that `&!0: !FnPtr` never holds, since it's a rigid type that is also not a fn ptr, we successfully detect that these impls may never overlap.
[^1]: For the purposes of this example, I just ignored lifetimes, since it doesn't really matter.
Store #[stable] attribute's `since` value in structured form
Followup to https://github.com/rust-lang/rust/pull/116773#pullrequestreview-1680913901.
Prior to this PR, if you wrote an improper `since` version in a `stable` attribute, such as `#[stable(feature = "foo", since = "wat.0")]`, rustc would emit a diagnostic saying **_'since' must be a Rust version number, such as "1.31.0"_** and then throw out the whole `stable` attribute as if it weren't there. This strategy had 2 problems, both fixed in this PR:
1. If there was also a `#[deprecated]` attribute on the same item, rustc would want to enforce that the stabilization version is older than the deprecation version. This involved reparsing the `stable` attribute's `since` version, with a diagnostic **_invalid stability version found_** if it failed to parse. Of course this diagnostic was unreachable because an invalid `since` version would have already caused the `stable` attribute to be thrown out. This PR deletes that unreachable diagnostic.
2. By throwing out the `stable` attribute when `since` is invalid, you'd end up with a second diagnostic saying **_function has missing stability attribute_** even though your function is not missing a stability attribute. This PR preserves the `stable` attribute even when `since` cannot be parsed, avoiding the misleading second diagnostic.
Followups I plan to try next:
- Do the same for the `since` value of `#[deprecated]`.
- See whether it makes sense to also preserve `stable` and/or `unstable` attributes when they contain an invalid `feature`. What redundant/misleading diagnostics can this eliminate? What problems arise from not having a usable feature name for some API, in the situation that we're already failing compilation, so not concerned about anything that happens in downstream code?
