Add `SliceLike` to `rustc_type_ir`, use it in the generic solver code (+ some other changes)
First, we split out `TraitRef::new_from_args` which takes *just* `ty::GenericArgsRef` from `TraitRef::new` which takes `impl IntoIterator<Item: Into<GenericArg>>`. I will explain in a minute why.
Second, we introduce `SliceLike`, which allows us to be generic over `List<T>` and `[T]`. This trait has an `as_slice()` and `into_iter()` method, and some other convenience functions. However, importantly, since types like `I::GenericArgs` now implement `SliceLike` rather than `IntoIter<Item = I::GenericArg>`, we can't use `TraitRef::new` on this directly. That's where `new_from_args` comes in.
Finally, we adjust all the code to use these slice operators. Some things get simpler, some things get a bit more annoying since we need to use `as_slice()` in a few places. 🤷
r? lcnr
Rollup of 11 pull requests
Successful merges:
- #124460 (Show notice about "never used" of Debug for enum)
- #124712 (Deprecate no-op codegen option `-Cinline-threshold=...`)
- #125082 (Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.)
- #125575 (SmartPointer derive-macro)
- #126413 (compiletest: make the crash test error message abit more informative)
- #126673 (Ensure we don't accidentally succeed when we want to report an error)
- #126682 (coverage: Overhaul validation of the `#[coverage(..)]` attribute)
- #126899 (Suggest inline const blocks for array initialization)
- #126904 (Small fixme in core now that NonZero is generic)
- #126909 (add `@kobzol` to bootstrap team for triagebot)
- #126911 (Split the lifetimes of `MirBorrowckCtxt`)
r? `@ghost`
`@rustbot` modify labels: rollup
Split the lifetimes of `MirBorrowckCtxt`
These lifetimes are sometimes too general and will link things together that are independent. These are a blocker for actually finishing tracking more state (e.g. error tainting) in the diagnostic context handle, and I'd rather land it in its own PR instead of together with functional changes.
Also changes a bunch of named lifetimes to `'_` where they were irrelevant
follow-up to https://github.com/rust-lang/rust/pull/126623
coverage: Overhaul validation of the `#[coverage(..)]` attribute
This PR makes sweeping changes to how the (currently-unstable) coverage attribute is validated:
- Multiple coverage attributes on the same item/expression are now treated as an error.
- The attribute must always be `#[coverage(off)]` or `#[coverage(on)]`, and the error messages for this are more consistent.
- A trailing comma is still allowed after off/on, since that's part of the normal attribute syntax.
- Some places that silently ignored a coverage attribute now produce an error instead.
- These cases were all clearly bugs.
- Some places that ignored a coverage attribute (with a warning) now produce an error instead.
- These were originally added as lints, but I don't think it makes much sense to knowingly allow new attributes to be used in meaningless places.
- Some of these errors might soon disappear, if it's easy to extend recursive coverage attributes to things like modules and impl blocks.
---
One of the goals of this PR is to lay a more solid foundation for making the coverage attribute recursive, so that it applies to all nested functions/closures instead of just the one it is directly attached to.
Fixes#126658.
This PR incorporates #126659, which adds more tests for validation of the coverage attribute.
`@rustbot` label +A-code-coverage
Ensure we don't accidentally succeed when we want to report an error
This also changes the `DefiningOpaqueTypes::No` to `Yes` without adding tests, as it is solely run on the error path to improve diagnostics. I was unable to provide a test that changes diagnostics, as all the tests I came up with ended up successfully constraining the opaque type and thus succeeding the coercion.
r? ```@compiler-errors```
cc https://github.com/rust-lang/rust/issues/116652
SmartPointer derive-macro
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Possibly replacing #123472 for continued upkeep of the proposal rust-lang/rfcs#3621 and implementation of the tracking issue #123430.
cc `@Darksonn` `@wedsonaf`
Remove `MaybeUninit::uninit_array()` and replace it with inline const blocks.
\[This PR originally contained the changes in #125995 too. See edit history for the original PR description.]
The documentation of `MaybeUninit::uninit_array()` says:
> Note: in a future Rust version this method may become unnecessary when Rust allows [inline const expressions](https://github.com/rust-lang/rust/issues/76001). The example below could then use `let mut buf = [const { MaybeUninit::<u8>::uninit() }; 32];`.
The PR adding it also said: <https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a standard library method that will be replaceable with `let buffer = [MaybeUninit::<T>::uninit(); $N];`
That time has come to pass — inline const expressions are stable — so `MaybeUninit::uninit_array()` is now unnecessary. The only remaining question is whether it is an important enough *convenience* to keep it around.
I believe it is net good to remove this function, on the principle that it is better to compose two orthogonal features (`MaybeUninit` and array construction) than to have a specific function for the specific combination, now that that is possible.
Deprecate no-op codegen option `-Cinline-threshold=...`
This deprecates `-Cinline-threshold` since using it has no effect. This has been the case since the new LLVM pass manager started being used, more than 2 years ago.
Recommend using `-Cllvm-args=--inline-threshold=...` instead.
Closes#89742 which is E-help-wanted.
Show notice about "never used" of Debug for enum
Close#123068
If an ADT implements `Debug` trait and it is not used, the compiler says a note that indicates intentionally ignored during dead code analysis as [this note](2207179a59/tests/ui/lint/dead-code/unused-variant.stderr (L9)).
However this node is not shown for variants that have fields in enum. This PR fixes to show the note.
Save 2 pointers in `TerminatorKind` (96 → 80 bytes)
These things don't need to be `Vec`s; boxed slices are enough.
The frequent one here is call arguments, but MIR building knows the number of arguments from the THIR, so the collect is always getting the allocation right in the first place, and thus this shouldn't ever add the shrink-in-place overhead.
This is possible now that inline const blocks are stable; the idea was
even mentioned as an alternative when `uninit_array()` was added:
<https://github.com/rust-lang/rust/pull/65580#issuecomment-544200681>
> if it’s stabilized soon enough maybe it’s not worth having a
> standard library method that will be replaceable with
> `let buffer = [MaybeUninit::<T>::uninit(); $N];`
Const array repetition and inline const blocks are now stable (in the
next release), so that circumstance has come to pass, and we no longer
have reason to want `uninit_array()` other than convenience. Therefore,
let’s evaluate the inconvenience by not using `uninit_array()` in
the standard library, before potentially deleting it entirely.
std: refactor the TLS implementation
As discovered by Mara in #110897, our TLS implementation is a total mess. In the past months, I have simplified the actual macros and their expansions, but the majority of the complexity comes from the platform-specific support code needed to create keys and register destructors. In keeping with #117276, I have therefore moved all of the `thread_local_key`/`thread_local_dtor` modules to the `thread_local` module in `sys` and merged them into a new structure, so that future porters of `std` can simply mix-and-match the existing code instead of having to copy the same (bad) implementation everywhere. The new structure should become obvious when looking at `sys/thread_local/mod.rs`.
Unfortunately, the documentation changes associated with the refactoring have made this PR rather large. That said, this contains no functional changes except for two small ones:
* the key-based destructor fallback now, by virtue of sharing the implementation used by macOS and others, stores its list in a `#[thread_local]` static instead of in the key, eliminating one indirection layer and drastically simplifying its code.
* I've switched over ZKVM (tier 3) to use the same implementation as WebAssembly, as the implementation was just a way worse version of that
Please let me know if I can make this easier to review! I know these large PRs aren't optimal, but I couldn't think of any good intermediate steps.
`@rustbot` label +A-thread-locals
Rollup of 4 pull requests
Successful merges:
- #125241 (Add `rust_analyzer` as a predefined tool)
- #126213 (Update docs for AtomicBool/U8/I8 with regard to alignment)
- #126414 (Tier 2 std support must always be known)
- #126882 (Special case when a code line only has multiline span starts)
r? `@ghost`
`@rustbot` modify labels: rollup
Special case when a code line only has multiline span starts
Minimize multline span overlap when there are multiple of them starting on the same line:
```
3 | X0 Y0 Z0
| _____^ - -
| | _______| |
| || _________|
4 | ||| X1 Y1 Z1
5 | ||| X2 Y2 Z2
| |||____^__-__- `Z` label
| ||_____|__|
| |______| `Y` is a good letter too
| `X` is a good letter
```
Tier 2 std support must always be known
We should never have a tier 2 target without knowing its support status so I think this line in the tier 2 section is a bit wrong:
> ? indicates the standard library support is unknown or a work-in-progress.
My first inclination was just to drop the "unknown or" part. However, after thinking about it some more, I think we should just use `✓` for this. The only affected targets are UEFI and frankly there are targets with worse std support that are marked with `✓` (e.g. wasm).
I think a `✓` should mean "this supports building with std (and is checked in CI for tier 2+)". The target errata can detail the current limitations or special requirements for doing so.
Update docs for AtomicBool/U8/I8 with regard to alignment
Fixes#126084.
Since `AtomicBool`/`AtomicU8`/`AtomicI8` are guaranteed to have size == 1, and Rust guarantees that `size % align == 0`, they also must have alignment equal to 1, so some current docs are contradictory/confusing when describing their alignment requirements.
Specifically:
* Fix `AtomicBool::from_ptr` claiming that `align_of::<AtomicBool>() > align_of::<bool>()` on some platforms. (same for `AtomicU8::from_ptr`/`AtomicI8::from_ptr`)
* Explicitly state that `AtomicU8`/`AtomicI8` have the same alignment as `u8`/`i8` (in addition to size and bit validity)
* (internal) Change the `if_not_8_bit` macro to be `if_8_bit` and to allow an "if-else"-like structure, instead of just "if"-like.
---
I opted to leave the "`ptr` must be aligned" wording in `from_ptr`'s docs and just clarify that it is always satsified, instead of just removing the wording entirely. If that is instead preferred I can do that.
It might make sense to allow this in the future, if we add values that aren't
mutually exclusive, but for now having multiple coverage attributes on one item
is useless.
Rollup of 9 pull requests
Successful merges:
- #126177 (Add hard error and migration lint for unsafe attrs)
- #126298 (Promote loongarch64-unknown-linux-musl to Tier 2 with host tools)
- #126455 (For [E0308]: mismatched types, when expr is in an arm's body, not add semicolon ';' at the end of it.)
- #126754 (Implement `use<>` formatting in rustfmt)
- #126807 (std::unix::fs: copy simplification for apple.)
- #126845 (Weekly `cargo update`)
- #126849 (Fix 32-bit Arm reg classes by hierarchically sorting them)
- #126854 (std::unix::os::home_dir: fallback's optimisation.)
- #126888 (Remove stray println from rustfmt's `rewrite_static`)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove stray println from rustfmt's `rewrite_static`
r? `@calebcartwright` `@ytmimi` -- though anyone should probably r+ this so it gets into nightly sooner than later, since it's obviously wrong.
This can just be fixed in-tree, since I don't think we want to wait until the next sync to fix this.
Fix https://github.com/rust-lang/rustfmt/issues/6210
Fix https://github.com/rust-lang/rust/issues/126887
Fix 32-bit Arm reg classes by hierarchically sorting them
We were rejecting legal `asm!` because we were asking for the "greatest" feature that includes a register class, instead of the "least" feature that includes a register class. This was only revealed on certain 32-bit Arm targets because not all have the same register limitations.
This is a somewhat hacky solution, but other solutions would require potentially rearchitecting how the internals of parsing or rejecting register classes work for all targets.
Fixes#126797
r? ``@Amanieu``
std::unix::fs: copy simplification for apple.
since we do support from macOs Sierra, we avoid the little runtime overhead with the fclonefileat symbol check.
Implement `use<>` formatting in rustfmt
This PR implements formatting for precise-capturing `use<>` syntax as proposed in https://github.com/rust-lang/rust/pull/126753.
The syntax is implemented as-if the `use<>` bound were a trait bound but with the `use` keyword as its path segment identifier.
I opted to develop this in the rust-lang/rust tree since I'm not certain when the next rustfmt subtree sync is going to be, and I'd rather not block landing nightly support for `use<>` on something I have no control over. If ``@rust-lang/rustfmt`` would rather I move this PR over to that repository, then I would at least like to know when the next rustfmt->rust subtree sync is going to be, since stabilizing `precise_capturing` without formatting will be disruptive.
This implementation is otherwise rather straightforward.
Tracking:
- https://github.com/rust-lang/rust/issues/123432
For [E0308]: mismatched types, when expr is in an arm's body, not add semicolon ';' at the end of it.
For [E0308]: mismatched types, when expr is in an arm's body, and it is the end expr without a semicolon of the block, not add semicolon ';' at the end of it.
fixes#126222
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