Fix uses of "adaptor"
These docs are in en_US, so "adapter" is the correct spelling (and indeed used in the next line.)
A second commit comes along for the ride to fix other instances in non-rustdoc comments.
Rehome 30 `tests/ui/issues/` tests to other subdirectories under `tests/ui/` [#3 of Batch #2]
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
Less greedily parse `[const]` bounds
> [!IMPORTANT]
> If you're coming here from any beta backport nomination thread on Zulip, only the last commit is truly relevant (the first commit doesn't need to be backported, it only contains test modifications)!
Don't consider `[` to start a bound, only consider `[const]` in its entirety to do so. This drastically reduces (but doesn't eliminate!) the chance of *real* breakages. Like `const`, `~const` and `async` before, `[const]` unavoidably brings along theoretical breakages, see preexisting tests: `macro-const-trait-bound-theoretical-regression.rs` and `macro-async-trait-bound-theoretical-regression.rs`.
Side note: It's unfortunate that we have to do this but apart from the known fact that MBE hurts forward compatibility, the `[const]` syntax is simply a bit scuffed (also CC'ing https://github.com/rust-lang/rust/issues/146122, section (3)).
Fixes [after beta backport] rust-lang/rust#146417.
* 1st commit: Restore the original test intentions of several preexisting related tests that were unfortunately lost over time
* I've added a bunch of SCREAMING comments to make it less likely to be lost again
* CC PR rust-lang/rust#119099 which added most of these tests
* CC [#144409 (comment)](https://github.com/rust-lang/rust/pull/144409#discussion_r2337587513) for further context (NB: It's not the only PR that negatively affected the test intention)
* 2nd commit: Actually address the regression
r? `@oli-obk` or anyone
Suggest bounds in more cases, accounting for type parameters referenced in predicate
Use a `ty::Visitor` to see if the failed predicate references a type parameter. If it does, then we only suggest adding a bound to an (associated) item only if the referenced parameter is present in its generics.
Provide adding bound suggestion in trait and impl associated functions in cases we previously weren't:
```
error[E0277]: `?` couldn't convert the error to `ApplicationError`
--> $DIR/suggest-complex-bound-on-method.rs:18:16
|
LL | t.run()?;
| -----^ the trait `From<<T as Trait>::Error>` is not implemented for `ApplicationError`
| |
| this can't be annotated with `?` because it has type `Result<_, <T as Trait>::Error>`
|
note: `ApplicationError` needs to implement `From<<T as Trait>::Error>`
--> $DIR/suggest-complex-bound-on-method.rs:12:1
|
LL | enum ApplicationError {
| ^^^^^^^^^^^^^^^^^^^^^
= note: the question mark operation (`?`) implicitly performs a conversion on the error value using the `From` trait
help: consider introducing a `where` clause, but there might be an alternative better way to express this requirement
|
LL | fn thing<T: Trait>(&self, t: T) -> Result<(), ApplicationError> where ApplicationError: From<<T as Trait>::Error> {
| +++++++++++++++++++++++++++++++++++++++++++++++++
```
Fixrust-lang/rust#144734.
Constify conversion traits (part 1)
This is the first part of rust-lang/rust#144289 being split into smaller pieces. It adds/moves constness of several traits under the `const_convert` feature:
* `From`
* `Into`
* `TryFrom`
* `TryInto`
* `FromStr`
* `AsRef`
* `AsMut`
* `Borrow`
* `BorrowMut`
* `Deref`
* `DerefMut`
There are a few methods that are intrinsically tied to these traits which I've included in the feature. Particularly, those which are wrappers over `AsRef`:
* `ByteStr::new` (unstable under `bstr` feature)
* `OsStr::new`
* `Path::new`
Those which directly use `Into`:
* `Result::into_ok`
* `Result::into_err`
And those which use `Deref` and `DerefMut`:
* `Pin::as_ref`
* `Pin::as_mut`
* `Pin::as_deref_mut`
* `Option::as_deref`
* `Option::as_deref_mut`
* `Result::as_deref`
* `Result::as_deref_mut`
(note: the `Option` and `Result` methods were suggested by ``@npmccallum`` initially as rust-lang/rust#146101)
The parts which are missing from this PR are:
* Anything that involves heap-allocated types
* Making any method const than the ones listed above
* Anything that could rely on the above, *or* could rely on system-specific code for `OsStr` or `Path` (note: this mostly makes these methods useless since `str` doesn't implement `AsRef<OsStr>` yet, but it's better to track the method for now and add impls later, IMHO)
r? ``@tgross35`` (who mostly already reviewed this)
Rehome 30 `tests/ui/issues/` tests to other subdirectories under `tests/ui/` [#2 of Batch #2]
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
Rehome 30 `tests/ui/issues/` tests to other subdirectories under `tests/ui/` [#1 of Batch #2]
Part of rust-lang/rust#133895
Methodology:
1. Refer to the previously written `tests/ui/SUMMARY.md`
2. Find an appropriate category for the test, using the original issue thread and the test contents.
3. Add the issue URL at the bottom (not at the top, as that would mess up stderr line numbers)
4. Rename the tests to make their purpose clearer
Inspired by the methodology that `@Kivooeo` was using.
r? `@jieyouxu`
When determining if a trait has no entries for the purposes of omitting vptrs from subtrait vtables, consider its transitive supertraits' entries, instead of just its own entries.
When determining if a non-first supertrait vptr can be omitted from a subtrait vtable, check if the supertrait or any of its (transitive) supertraits have methods, instead of only checking if the supertrait itself has methods.
This fixes the soundness issue where a vptr would be omitted for a supertrait with no methods but that itself had a supertrait with methods, while still optimizing the case where the supertrait is "truly" empty (it has no own vtable entries, and none of its (transitive) supertraits have any own vtable entries).
Fixes <https://github.com/rust-lang/rust/issues/145752>
-----
Old description:
~~Treat all non-auto traits as non-empty (possibly having methods) for purposes of determining if we need to emit a vptr for a non-direct supertrait (and for new "sibling" entries after a direct or non-direct supertrait).~~
This fixes (I believe) the soundness issue, ~~but regresses vtable sizes and possibly upcasting perf in some cases when using trait hierarchies with empty non-auto traits (see `tests/ui/traits/vtable/multiple-markers.stderr`) since we use vptrs in some cases where we could re-use the vtable.~~
Fixes <https://github.com/rust-lang/rust/issues/145752>
Re-opens (not anymore) <https://github.com/rust-lang/rust/issues/114942>
Should not affect <https://github.com/rust-lang/rust/issues/131813> (i.e. the soundness issue is still fixed, ~~though the relevant vtables in the `trait Evil` example will be larger now~~)
cc implementation history <https://github.com/rust-lang/rust/pull/131864> <https://github.com/rust-lang/rust/pull/113856>
-----
~~It should be possible to check if a trait has any methods from itself *or* supertraits (instead of just from itself), but to fix the immediate soundness issue, just assume any non-auto trait could have methods. A more optimistic check can be implemented later (or if someone does it soon it could just supercede this PR 😄).~~ Done in latest push
`@rustbot` label A-dyn-trait F-trait_upcasting
change HIR typeck region uniquification handling approach
rust-lang/rust#144405 causes structural lookup of opaque types to not work during HIR typeck, so instead avoid uniquifying goals and instead only reprove them if MIR borrowck actually encounters an error.
This doesn't perfectly maintain the property that HIR typeck succeeding implies that MIR typeck succeeds, instead weakening this check to only guarantee that HIR typeck implies that MIR typeck succeeds modulo region uniquification. This means we still get the actually desirable ICEs if we MIR building is broken or we forget to check some property in HIR typeck, without having to deal with the fallout of uniquification in HIR typeck itself.
We report errors using the original obligation sources of HIR typeck so diagnostics aren't that negatively impacted either.
Here's the history of region uniquification while working on the new trait solver:
- rust-lang/rust#107981
- rust-lang/rust#110180
- rust-lang/rust#114117
- rust-lang/rust#130821
- rust-lang/rust#144405
- rust-lang/rust#145706 <- we're here 🎉
r? `@BoxyUwU`
When encountering an unmet trait bound, point at local type that doesn't implement the trait:
```
error[E0277]: the trait bound `Bar<T>: Foo` is not satisfied
--> $DIR/issue-64855.rs:9:19
|
LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ;
| ^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
|
help: the trait `Foo` is not implemented for `Bar<T>`
--> $DIR/issue-64855.rs:9:1
|
LL | pub struct Bar<T>(<Self as Foo>::Type) where Self: ;
| ^^^^^^^^^^^^^^^^^
```
Unconditionally-const supertraits are considered not dyn compatible
Let's save some space in the design of const traits by making `dyn Trait` where `trait Trait: const Super` not dyn compatible.
Such a trait cannot satisfy `dyn Trait: Trait`; we could in the future make this dyn compatible but *NOT* implement `Trait`, but that's a bit weird and seems like it needs to be independently justified moving forward.
Fixes https://github.com/rust-lang/rust/issues/145198
r? fee1-dead
mention lint group in default level lint note
### Summary
This PR updates lint diagnostics so that default-level notes now mention the lint group they belong to, if any.
Fixes: rust-lang/rust#65464.
### Example
```rust
fn main() {
let x = 5;
}
```
Before:
```
= note: `#[warn(unused_variables)]` on by default
```
After:
```
= note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
```
### Unchanged Cases
Messages remain the same when the lint level is explicitly set, e.g.:
* Attribute on the lint `#[warn(unused_variables)]`:
```
note: the lint level is defined here
LL | #[warn(unused_variables)]
| ^^^^^^^^^^^^^^^^
```
* Attribute on the group `#[warn(unused)]:`:
```
= note: `#[warn(unused_variables)]` implied by `#[warn(unused)]`
```
* CLI option `-W unused`:
```
= note: `-W unused-variables` implied by `-W unused`
= help: to override `-W unused` add `#[allow(unused_variables)]`
```
* CLI option `-W unused-variables`:
```
= note: requested on the command line with `-W unused-variables`
```
ignore head usages from ignored candidates
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/210. The test now takes 0.8s to compile, which seems good enough to me. We are actually still walking the entire graph here, we're just avoiding unnecessary reruns.
The basic idea is that if we've only accessed a cycle head inside of a candidate which didn't impact the final result of our goal, we don't need to rerun that cycle head even if is the used provisional result differs from the final result.
We also use this information when rebasing goals over their cycle heads. If a goal doesn't actually depend on the result of that cycle head, rebasing always succeeds. However, we still need to make sure we track the fact that we relied on the cycle head at all to avoid query instability.
It is implemented by tracking the number of `HeadUsages` for every head while evaluating goals. We then also track the head usages while evaluating a single candidate, which the search graph returns as `CandidateHeadUsages`. If there is now an always applicable candidate candidate we know that all other candidates with that source did not matter. We then call `fn ignore_candidate_head_usages` to remove the usages while evaluating this single candidate from the total. If the final `HeadUsages` end up empty, we know that the result of this cycle head did not matter when evaluating its nested goals.
