make sure ScalarPair enums have ScalarPair variants; add some layout sanity checks
`@eddyb` suggested that it might be reasonable for `ScalarPair` enums to simply adjust the ABI of their variants accordingly, such that the layout invariant Miri expects actually holds. This PR implements that. I should note though that I don't know much about this layout computation code and what non-Miri consumers expect from it, so tread with caution!
I also added a function to sanity-check that computed layouts are internally consistent. This helped a lot in figuring out the final shape of this PR, though I am also not 100% sure that these sanity checks are the right ones.
Cc `@oli-obk`
Fixes https://github.com/rust-lang/rust/issues/96221
Properly fix#96638Closes#96638
The main part of this change is `Error::Invalid` now returns both the input and arg indices. However, I realized the code here was kind of confusing and not internally consistent (and thus I was having trouble getting the right behavior). So I've also switched `input_indices` and `arg_indices` to more closely match some naming in `checks` (although I think a more thorough cleanup there could be beneficial). I've added comments, but essentially `input_indices` refers to *user provided* inputs and `arg_indices` refers to *expected* args.
Do not lint on explicit outlives requirements from external macros.
The current implementation of the list rightfully skipped where predicates from external macros.
However, if the where predicate came from the current macro but the bounds were from an external macro, the lint still fired.
Closes https://github.com/rust-lang/rust/issues/96640
This fixes#96449, but I haven't yet been able to
make the reproducer work using `#[cfg]` attributes,
so we can't use the 'revision' infra to write a test
The previous implementation relied on sorting by `PlaceRef`.
This requires sorting by a `DefId`, which uses untracked state
(see #93315)
Fortify handing of where bounds on trait & trait alias definitions
Closes https://github.com/rust-lang/rust/issues/96664
Closes https://github.com/rust-lang/rust/issues/96665
Since https://github.com/rust-lang/rust/pull/93803, when listing all bounds and predicates we now need to account for the possible presence of predicates on any of the generic parameters. Both bugs were hidden by the special handling of bounds at the generic parameter declaration position.
Trait alias expansion used to confuse predicates on `Self` and where predicates.
Exiting too late when listing all the bounds caused a cycle error.
Optimize switch sources representation and usage
* Avoid constructing switch sources unless necessary - switch sources are used by backward analysis with a custom switch int edge effects, but are otherwise unnecessarily computed.
* Use sparse representation of switch sources to avoid quadratic space overhead.
Some subst cleanup
Two separate things here. Both changes are useful for some refactoring I'm doing to add an "EarlyBinder" newtype. (Part of chalkification).
1) Remove `subst_spanned` and just use `subst`. It wasn't used much anyways. In practice, I think we can probably get most of the info just from the actual error message. If not, outputting logs should do the trick. (The specific line probably wouldn't help much anyways).
2) Call `.subst()` before `replace_bound_vars_with_fresh_vars` and `erase_late_bound_regions` in three places that do the opposite. I think there might have been some time in the past that the order here matter for something, but this shouldn't be the case anymore. Conceptually, it makes more sense to the of the *early bound* vars on `fn`s as "outside" the late bound vars.
Actually fix ICE from #96583
PR #96746 fixed a very similar bug, so the same logic is used in a different place.
I originally concluded that the two issues (#96583 and #96738) were identical by comparing the backtrace, but I didn't look close enough.
Warn on unused `#[doc(hidden)]` attributes on trait impl items
[Zulip conversation](https://rust-lang.zulipchat.com/#narrow/stream/266220-rustdoc/topic/.E2.9C.94.20Validy.20checks.20for.20.60.23.5Bdoc.28hidden.29.5D.60).
Whether an associated item in a trait impl is shown or hidden in the documentation entirely depends on the corresponding item in the trait declaration. Rustdoc completely ignores `#[doc(hidden)]` attributes on impl items. No error or warning is emitted:
```rust
pub trait Tr { fn f(); }
pub struct Ty;
impl Tr for Ty { #[doc(hidden)] fn f() {} }
// ^^^^^^^^^^^^^^ ignored by rustdoc and currently
// no error or warning issued
```
This may lead users to the wrong belief that the attribute has an effect. In fact, several such cases are found in the standard library (I've removed all of them in this PR).
There does not seem to exist any incentive to allow this in the future either: Impl'ing a trait for a type means the type *fully* conforms to its API. Users can add `#[doc(hidden)]` to the whole impl if they want to hide the implementation or add the attribute to the corresponding associated item in the trait declaration to hide the specific item. Hiding an implementation of an associated item does not make much sense: The associated item can still be found on the trait page.
This PR emits the warn-by-default lint `unused_attribute` for this case with a future-incompat warning.
`@rustbot` label T-compiler T-rustdoc A-lint
optimize `promote_consts` by caching the results of `validate_local`
From the FIXME in the impl of `promote_consts`. Early return the `validate_local` should save some compile time.
`qualif_local` is similar to this, but requires futher changing because there are different types of qualif checks. If this PR is effective, I will do it as well.
Remove `#[rustc_deprecated]`
This removes `#[rustc_deprecated]` and introduces diagnostics to help users to the right direction (that being `#[deprecated]`). All uses of `#[rustc_deprecated]` have been converted. CI is expected to fail initially; this requires #95958, which includes converting `stdarch`.
I plan on following up in a short while (maybe a bootstrap cycle?) removing the diagnostics, as they're only intended to be short-term.
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`
