Warn for #[unstable] on trait impls when it has no effect.
Earlier today I sent a PR with an `#[unstable]` attribute on a trait `impl`, but was informed that this attribute has no effect there. (comment: https://github.com/rust-lang/rust/pull/76525#issuecomment-689678895, issue: https://github.com/rust-lang/rust/issues/55436)
This PR adds a warning for this situation. Trait `impl` blocks with `#[unstable]` where both the type and the trait are stable will result in a warning:
```
warning: An `#[unstable]` annotation here has no effect. See issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information.
--> library/std/src/panic.rs:235:1
|
235 | #[unstable(feature = "integer_atomics", issue = "32976")]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
---
It detects three problems in the existing code:
1. A few `RefUnwindSafe` implementations for the atomic integer types in `library/std/src/panic.rs`. Example:
d92155bf6a/library/std/src/panic.rs (L235-L236)
2. An implementation of `Error` for `LayoutErr` in `library/std/srd/error.rs`:
d92155bf6a/library/std/src/error.rs (L392-L397)
3. `From` implementations for `Waker` and `RawWaker` in `library/alloc/src/task.rs`. Example:
d92155bf6a/library/alloc/src/task.rs (L36-L37)
Case 3 interesting: It has a bound with an `#[unstable]` trait (`W: Wake`), so appears to have much effect on stable code. It does however break similar blanket implementations. It would also have immediate effect if `Wake` was implemented for any stable type. (Which is not the case right now, but there are no warnings in place to prevent it.) Whether this case is a problem or not is not clear to me. If it isn't, adding a simple `c.visit_generics(..);` to this PR will stop the warning for this case.
Finish off revisions for const generics UI tests.
This time it really does fix it. 😅 The only ones left are `min-and-full-same-time.rs`, which doesn't need it, and `array-impls/` which check the feature indirectly.
Fixes#75279.
r? @lcnr
Add saturating methods for `Duration`
In some project, I needed a `saturating_add` method for `Duration`. I implemented it myself but i thought it would be a nice addition to the standard library as it matches closely with the integers types.
3 new methods have been introduced and are gated by the new `duration_saturating_ops` unstable feature:
* `Duration::saturating_add`
* `Duration::saturating_sub`
* `Duration::saturating_mul`
If have left the tracking issue to `none` for now as I want first to understand if those methods would be acceptable at all. If agreed, I'll update the PR with the tracking issue.
Further more, to match the behavior of integers types, I introduced 2 associated constants:
* `Duration::MIN`: this one is somehow a duplicate from `Duration::zero()` method, but at the time this method was added, `MIN` was rejected as it was considered a different semantic (see https://github.com/rust-lang/rust/pull/72790#issuecomment-636511743).
* `Duration::MAX`
Both have been gated by the already existing unstable feature `duration_constants`, I can introduce a new unstable feature if needed or just re-use the `duration_saturating_ops`.
We might have to decide whether:
* `MIN` should be replaced by `ZERO`?
* associated constants over methods?
Give better suggestion when const Range*'s are used as patterns
Fixes#76191
let me know if there is more/different information you want to show in this case
Improve suggestions for broken intra-doc links
~~Depends on #74489 and should not be merged before that PR.~~ Merged 🎉
~~Depends on #75916 and should not be merged before.~~ Merged
Fixes https://github.com/rust-lang/rust/issues/75305.
This does a lot of different things 😆.
- Add `PerNS::into_iter()` so I didn't have to keep rewriting hacks around it. Also add `PerNS::iter()` for consistency. Let me know if this should be `impl IntoIterator` instead.
- Make `ResolutionFailure` an enum instead of a unit variant. This was most of the changes: everywhere that said `ErrorKind::ResolutionFailure` now has to say _why_ the link failed to resolve.
- Store the resolution in case of an anchor failure. Previously this was implemented as variants on `AnchorFailure` which was prone to typos and had inconsistent output compared to the rest of the diagnostics.
- Turn some `Err`ors into unwrap() or panic()s, because they're rustdoc bugs and not user error. These have comments as to why they're bugs (in particular this would have caught #76073 as a bug a while ago).
- If an item is not in scope at all, say the first segment in the path that failed to resolve
- If an item exists but not in the current namespaces, say that and suggests linking to that namespace.
- If there is a partial resolution for an item (part of the segments resolved, but not all of them), say the partial resolution and why the following segment didn't resolve.
- Add the `DefId` of associated items to `kind_side_channel` so it can be used for diagnostics (tl;dr of the hack: the rest of rustdoc expects the id of the item, but for diagnostics we need the associated item).
- No longer suggests escaping the brackets for every link that failed to resolve; this was pretty obnoxious. Now it only suggests `\[ \]` if no segment resolved and there is no `::` in the link.
- Add `Suggestion`, which says _what_ to prefix the link with, not just 'prefix with the item kind'.
Places where this is currently buggy:
<details><summary>All outdated</summary>
~~1. When the link has the wrong namespace:~~ Now fixed.
<details>
```rust
/// [type@S::h]
impl S {
pub fn h() {}
}
/// [type@T::g]
pub trait T {
fn g() {}
}
```
```
error: unresolved link to `T::g`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:53:6
|
53 | /// [type@T::g]
| ^^^^^^^^^
|
= note: this link partially resolves to the trait `T`,
= note: `T` has no field, variant, or associated item named `g`
error: unresolved link to `S::h`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:48:6
|
48 | /// [type@S::h]
| ^^^^^^^^^
|
= note: this link partially resolves to the struct `S`,
= note: `S` has no field, variant, or associated item named `h`
```
Instead it should suggest changing the disambiguator, the way it currently does for macros:
```
error: unresolved link to `S`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:38:6
|
38 | /// [S!]
| ^^ help: to link to the unit struct, use its disambiguator: `value@S`
|
= note: this link resolves to the unit struct `S`, which is not in the macro namespace
```
</details>
2. ~~Associated items for values. It says that the value isn't in scope; instead it should say that values can't have associated items.~~ Fixed.
<details>
```
error: unresolved link to `f::A`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:14:6
|
14 | /// [f::A]
| ^^^^
|
= note: no item named `f` is in scope
= help: to escape `[` and `]` characters, add '\' before them like `\[` or `\]`
```
This is _mostly_ fixed, it now says
```rust
warning: unresolved link to `f::A`
--> /home/joshua/test-rustdoc/f.rs:1:6
|
1 | /// [f::A]
| ^^^^
|
= note: this link partially resolves to the function `f`
= note: `f` is a function, not a module
```
'function, not a module' seems awfully terse when what I actually mean is '`::` isn't allowed here', though.
</details>
It looks a lot nicer now, it says
```
error: unresolved link to `f::A`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:13:6
|
13 | /// [f::A]
| ^^^^
|
= note: `f` is a function, not a module or type, and cannot have associated items
```
3. ~~I'm also not very happy with the second note for this error:~~
<details>
```
error: unresolved link to `S::A`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:19:6
|
19 | /// [S::A]
| ^^^^
|
= note: this link partially resolves to the struct `S`,
= note: `S` has no field, variant, or associated item named `A`
```
but I'm not sure how better to word it.
I ended up going with 'no `A` in `S`' to match `rustc_resolve` but that seems terse as well.
</details>
This now says
```
error: unresolved link to `S::A`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:17:6
|
17 | /// [S::A]
| ^^^^
|
= note: the struct `S` has no field or associated item named `A`
```
which I think looks pretty good :)
4. This is minor, but it would be nice to say that `path` wasn't found instead of the full thing:
```
error: unresolved link to `path::to::nonexistent::module`
--> /home/joshua/rustc/src/test/rustdoc-ui/intra-link-errors.rs:8:6
|
8 | /// [path::to::nonexistent::module]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
It will now look at most 3 paths up (so it reports `path::to` as not in scope), but it doesn't work with arbitrarily many paths.
</details>
~~I recommend only reviewing the last few commits - the first 7 are all from #74489.~~ Rebased so that only the relevant commits are shown. Let me know if I should squash the history some more.
r? `@estebank`
Give better diagnostic when using a private tuple struct constructor
Fixes#75907
Some notes:
1. This required some deep changes, including removing a Copy impl for PatKind. If some tests fail, I would still appreciate review on the overall approach
2. this only works with basic patterns (no wildcards for example), and fails if there is any problems getting the visibility of the fields (i am not sure what the failure that can happen in resolve_visibility_speculative, but we check the length of our fields in both cases against each other, so if anything goes wrong, we fall back to the worse error. This could be extended to more patterns
3. this does not yet deal with #75906, but I believe it will be similar
4. let me know if you want more tests
5. doesn't yet at the suggestion that `@yoshuawuyts` suggested at the end of their issue, but that could be added relatively easily (i believe)
Add help note when using type in place of const
This adds a small help note when it might be possible that wrapping a parameter in braces might resolve the issue of having a type where a const was expected.
Currently, I am displaying the `HirId`, and I'm not particularly sure where to get the currently displayed path(?).
r? `@lcnr`
add the `const_evaluatable_checked` feature
Implements a rather small subset of https://github.com/rust-lang/compiler-team/issues/340
Unlike the MCP, this does not try to compare different constant, but instead only adds the constants found in where clauses
to the predicates of a function. This PR adds the feature gate `const_evaluatable_checked`, without which nothing should change.
r? @oli-obk @eddyb
typeck: don't suggest inaccessible private fields
Fixes#76077.
This PR adjusts the missing field diagnostic logic in typeck so that when none of the missing fields in a struct expr are accessible then the error is less confusing.
r? @estebank
Add revisions to const generic issue UI tests.
Fixes#75279.
I have gotten into the flow, so I can do more of these if requested. I'm looking for feedback as to whether my work is on the right track so far.
This commit adjusts the missing field diagnostic logic for struct
patterns in typeck to improve the diagnostic when the missing fields are
inaccessible.
Signed-off-by: David Wood <david@davidtw.co>
This commit adjusts the missing field diagnostic logic for struct
expressions in typeck to improve the diagnostic when the missing
fields are inaccessible.
Signed-off-by: David Wood <david@davidtw.co>
rustbuild: Build tests with LLD if `use-lld = true` was passed
Addresses https://github.com/rust-lang/rust/pull/76127#discussion_r479932392.
Our test suite is generally ready to run with an explicitly specified linker (https://github.com/rust-lang/rust/pull/45191),
so LLD specified with `use-lld = true` works as well.
Only 4 tests fail (on `x86_64-pc-windows-msvc`):
```
ui/panic-runtime/lto-unwind.rs
run-make-fulldeps/debug-assertions
run-make-fulldeps/foreign-exceptions
run-make-fulldeps/test-harness
```
All of them are legitimate issues with LLD (or at least with combination Rust+LLD) and manifest in segfaults on access to TLS (https://github.com/rust-lang/rust/pull/76127#issuecomment-683473325). UPD: These issues are caused by https://github.com/rust-lang/rust/issues/72145 and appear because I had `-Ctarget-cpu=native` set.
UPD: Further commits build tests with LLD for non-MSVC targets and propagate LLD to more places when `use-lld` is enabled.
Add CONST_ITEM_MUTATION lint
Fixes#74053Fixes#55721
This PR adds a new lint `CONST_ITEM_MUTATION`.
Given an item `const FOO: SomeType = ..`, this lint fires on:
* Attempting to write directly to a field (`FOO.field = some_val`) or
array entry (`FOO.array_field[0] = val`)
* Taking a mutable reference to the `const` item (`&mut FOO`), including
through an autoderef `FOO.some_mut_self_method()`
The lint message explains that since each use of a constant creates a
new temporary, the original `const` item will not be modified.
Improve unresolved use error message
"use of undeclared type or module `foo`" doesn't mention that it could be a crate.
This error can happen when users forget to add a dependency to `Cargo.toml`, so I think it's important to mention that it could be a missing crate.
I've used a heuristic based on Rust's naming conventions. It complains about an unknown type if the ident starts with an upper-case letter, and crate or module otherwise. It seems to work very well. The expanded error help covers both an unknown type and a missing crate case.
VS code graphviz extensions use d3-graphviz, which supports `Courier`
fontname but does not support `monospace`. This caused graphs to render
poorly because the text sizes were wrong.
make `ConstEvaluatable` more strict
relevant zulip discussion: https://rust-lang.zulipchat.com/#narrow/stream/146212-t-compiler.2Fconst-eval/topic/.60ConstEvaluatable.60.20generic.20functions/near/204125452
Let's see how much this impacts. Depending on how this goes this should probably be a future compat warning.
Short explanation: we currently forbid anonymous constants which depend on generic types, e.g. `[0; std::mem::size_of::<T>]` currently errors.
We previously checked this by evaluating the constant and returned an error if that failed. This however allows things like
```rust
const fn foo<T>() -> usize {
if std::mem::size_of::<*mut T>() < 8 { // size of *mut T does not depend on T
std::mem::size_of::<T>()
} else {
8
}
}
fn test<T>() {
let _ = [0; foo::<T>()];
}
```
which is a backwards compatibility hazard. This also has worrying interactions with mir optimizations (https://github.com/rust-lang/rust/pull/74491#issuecomment-661890421) and intrinsics (#74538).
r? `@oli-obk` `@eddyb`
Make rustdoc output deterministic for UI tests
Closes https://github.com/rust-lang/rust/issues/76442 (hopefully, since it's non-deterministic I don't have a way to test).
r? `@Mark-Simulacrum`
cc `@GuillaumeGomez`
Add help note to unconstrained const parameter
Resolves#68366, since it is currently intended behaviour.
If demonstrating `T -> U` is injective, there should be an additional word that it is not **yet** supported.
r? @lcnr
