Use ptr::metadata in <[T]>::len implementation
This avoids duplication of ptr::metadata code.
I believe this is acceptable as the previous approach essentially duplicated `ptr::metadata` because back then `rustc_allow_const_fn_unstable` annotation did not exist.
I would like somebody to ping `@rust-lang/wg-const-eval` as the documentation says:
> Always ping `@rust-lang/wg-const-eval` if you are adding more rustc_allow_const_fn_unstable attributes to any const fn.
Rollup of 11 pull requests
Successful merges:
- #100462 (Clarify `array::from_fn` documentation)
- #101644 (Document surprising and dangerous fs::Permissions behaviour on Unix)
- #103005 (kmc-solid: Handle errors returned by `SOLID_FS_ReadDir`)
- #103140 (Add diagnostic for calling a function with the same name with unresolved Macro)
- #103254 (rustdoc: do not filter out cross-crate `Self: Sized` bounds)
- #103347 (bootstrap: also create rustc-src component in sysroot)
- #103402 (Fix wrapped valid-range handling in ty_find_init_error)
- #103414 (Pretty print lifetimes captured by RPIT)
- #103424 (rustdoc: remove no-op CSS `.code-header { border-bottom: none }`)
- #103434 (Use functions for jump-to-def-background rustdoc GUI test)
- #103447 (`MaybeUninit`: use `assume_init_drop()` in the partially initialized array example)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
`MaybeUninit`: use `assume_init_drop()` in the partially initialized array example
The `assume_init_drop()` method does the same thing as the pointer conversion, and makes the example more straightforward.
rustdoc: remove no-op CSS `.code-header { border-bottom: none }`
The code headers are always h3 or h4, which don't have border-bottom by default anyway.
Pretty print lifetimes captured by RPIT
This specifically makes the output in #103409 change from:
```diff
error: `impl` item signature doesn't match `trait` item signature
--> $DIR/signature-mismatch.rs:15:5
|
LL | fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>;
| ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>>`
...
LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a {
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>>`
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2`
|
= note: expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>>`
- found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>>`
+ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2`
= help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait`
= help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output
error: aborting due to previous error
```
Along with the UI tests in this PR, which I think are all improvements!
r? `@oli-obk` though feel free to re-roll
Fix wrapped valid-range handling in ty_find_init_error
Rust's niche handling allows for wrapping valid ranges with end < start;
for instance, a valid range with start=43 and end=41 means a niche of
42. Most places in the compiler handle this correctly, but
`ty_find_init_error` assumed that `lo > 0` means the type cannot contain a
zero.
Fix it to handle wrapping ranges.
rustdoc: do not filter out cross-crate `Self: Sized` bounds
All type parameters **except `Self`** are implicitly `Sized` ([via](https://doc.rust-lang.org/nightly/std/marker/trait.Sized.html)). Previously, we disregarded the exception of `Self` and omitted cross-crate `Sized` bounds of *any* type parameter *including* `Self` when rendering.
From now on, we *do* render cross-crate `Self: Sized` bounds.
Most notably, in `std` we now finally properly render the `Sized` bound of the `Clone` trait as well as the `Self: Sized` bound on `Iterator::map`.
Fixes#24183.
``@rustbot`` label T-rustdoc A-cross-crate-reexports
r? rustdoc
kmc-solid: Handle errors returned by `SOLID_FS_ReadDir`
Fixes the issue where the `std::fs::ReadDir` implementaton of the [`*-kmc-solid_*`](https://doc.rust-lang.org/nightly/rustc/platform-support/kmc-solid.html) Tier 3 targets silently suppressed errors returned by the underlying `SOLID_FS_ReadDir` system function. The new implementation correctly handles all cases:
- `SOLID_ERR_NOTFOUND` indicates the end of directory stream.
- `SOLID_ERR_OK` + non-empty `d_name` indicates success.
- Some old filesystem drivers may return `SOLID_ERR_OK` + empty `d_name` to indicate the end of directory stream.
- Any other negative values (per ITRON convention) represent an error.
Document surprising and dangerous fs::Permissions behaviour on Unix
This documents the very surprising behaviour that `set_readonly(false)` will make a file *world writable* on Unix. I would go so far as to say that this function should be deprecated on Unix, or maybe even entirely. But documenting the bad behaviour is a good first step.
Fixes#74895
Clarify `array::from_fn` documentation
I've seen quite a few of people on social media confused of where the length of array is coming from in the newly stabilized `array::from_fn` example.
This PR tries to clarify the documentation on this.
Upgrade dist-mips*-linux to ubuntu:22.04 + crosstool-ng
These have no change in compatibility, still Linux 4.4 and glibc 2.23.
The main motivation for upgrading is that LLVM 16 will require at least GCC 7.1. Using crosstool-ng lets us choose our own toolchain versions, and then the Ubuntu version doesn't matter so much, just for the host compilation while we cross-compile.
Eliminate 280-byte memset from ReadDir iterator
This guy:
1536ab1b38/library/std/src/sys/unix/fs.rs (L589)
It turns out `libc::dirent64` is quite big—https://docs.rs/libc/0.2.135/libc/struct.dirent64.html. In #103135 this memset accounted for 0.9% of the runtime of iterating a big directory.
Almost none of the big zeroed value is ever used. We memcpy a tiny prefix (19 bytes) into it, and then read just 9 bytes (`d_ino` and `d_type`) back out. We can read exactly those 9 bytes we need directly from the original entry_ptr instead.
## History
This code got added in #93459 and tweaked in #94272 and #94750.
Prior to #93459, there was no memset but a full 280 bytes were being copied from the entry_ptr.
<table><tr><td>copy 280 bytes</td></tr></table>
This was not legal because not all of those bytes might be initialized, or even allocated, depending on the length of the directory entry's name, leading to a segfault. That PR fixed the segfault by creating a new zeroed dirent64 and copying just the guaranteed initialized prefix into it.
<table><tr><td>memset 280 bytes</td><td>copy 19 bytes</td></tr></table>
However this was still buggy because it used `addr_of!((*entry_ptr).d_name)`, which is considered UB by Miri in the case that the full extent of entry_ptr is not in bounds of the same allocation. (Arguably this shouldn't be a requirement, but here we are.)
The UB got fixed by #94272 by replacing `addr_of` with some pointer manipulation based on `offset_from`, but still fundamentally the same operation.
<table><tr><td>memset 280 bytes</td><td>copy 19 bytes</td></tr></table>
Then #94750 noticed that only 9 of those 19 bytes were even being used, so we could pick out only those 9 to put in the ReadDir value.
<table><tr><td>memset 280 bytes</td><td>copy 19 bytes</td><td>copy 9 bytes</td></tr></table>
After my PR we just grab the 9 needed bytes directly from entry_ptr.
<table><tr><td>copy 9 bytes</td></tr></table>
The resulting code is more complex but I believe still worthwhile to land for the following reason. This is an extremely straightforward thing to accomplish in C and clearly libc assumes that; literally just `entry_ptr->d_name`. The extra work in comparison to accomplish it in Rust is not an example of any actual safety being provided by Rust. I believe it's useful to have uncovered that and think about what could be done in the standard library or language to support this obvious operation better.
## References
- https://man7.org/linux/man-pages/man3/readdir.3.html
Enable LTO for rustc_driver.so
Alternative to https://github.com/rust-lang/rust/pull/97154
This enables LTO'ing dylibs behind a feature flag and uses this feature for compiling rustc_driver.so.
Rollup of 6 pull requests
Successful merges:
- #101293 (Recover when unclosed char literal is parsed as a lifetime in some positions)
- #101908 (Suggest let for assignment, and some code refactor)
- #103192 (rustdoc: Eliminate uses of `EarlyDocLinkResolver::all_traits`)
- #103226 (Check `needs_infer` before `needs_drop` during HIR generator analysis)
- #103249 (resolve: Revert "Set effective visibilities for imports more precisely")
- #103305 (Move some tests to more reasonable places)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
resolve: Revert "Set effective visibilities for imports more precisely"
In theory the change was correct, but in practice the use of import items in HIR is limited and hacky, and it expects that (effective) visibilities for all (up to) 3 IDs of the import are set to the value reflecting (effective) visibility of the whole syntactic `use` item rather than its individual components.
Fixes https://github.com/rust-lang/rust/issues/102352
r? `@oli-obk`
Check `needs_infer` before `needs_drop` during HIR generator analysis
This is kinda a revival of #103036, but with the understanding that after fallback, a generator-interior type will only have `needs_infer` true if there's an error that prevented int or float variable fallback to occur (modulo region variables, which are erased).
Therefore the best choice here is to delay a bug and skip the `needs_drop` call altogether.
r? `@lcnr` feel free to reassign though
Flatten diagnostic slug modules
This makes it easier to grep for the slugs in the code.
See https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/Localization.20infra.20interferes.20with.20grepping.20for.20error for more discussion about it.
This was mostly done with a few regexes and a bunch of manual work. This also exposes a pretty annoying inconsistency for the extra labels. Some of the extra labels are defined as additional properties in the fluent message (which makes them not prefixed with the crate name) and some of them are new fluent messages themselves (which makes them prefixed with the crate name). I don't know whether we want to clean this up at some point but it's useful to know.
r? `@davidtwco`
Change `unknown_lint` applicability to `MaybeIncorrect`
This small PR changes the applicability of `unknown_lint` to `MaybeIncorrect`, because the suggested lint might not be the correct one.
Here is one example where the current applicability causes a problem. Clippy has a set of internal lints guarded by a feature called `internal`. If the feature is not enabled, then the internal lints are "unknown." In that case, running `cargo clippy --fix ...` on `clippy_utils` causes lines such as the followig
26c96e3416/src/tools/clippy/clippy_utils/src/paths.rs (L51-L52)
to be changed to
```rust
#[expect(clippy::invalid_regex)] // internal lints do not know about all external crates
pub const FUTURES_IO_ASYNCREADEXT: [&str; 3] = ["futures_util", "io", "AsyncReadExt"];
```
which is not correct.
Delay ambiguity span bug in normalize query iff not rustdoc
Oli and I decided that the compiler debt of adding another usage of `tcx.sess.opts.actually_rustdoc` is fine, because we don't really want to add more complexity to the normalize query, and moving rustdoc to use fulfill normalization (`fully_normalize`, i.e. not use the normalize query) is unnecessary overhead given that it's skipping binders and stuff.
r? oli-obk
Fixes#102827Fixes#103181
Handle return-position `impl Trait` in traits properly in `register_hidden_type`
The bounds that we get by calling `bound_explicit_item_bounds` from an RPITIT have projections, not opaques, but when we're *registering* an opaque, we want to treat it like an opaque.
Coincidentally fixes#102688 as well, which makes sense, since that was failing because we were inferring an opaque type to be equal to itself (opaque cycle error => "cannot resolve opaque type").
Fixes#103352
r? ```@oli-obk```
Do not suggest trivially false const predicates
Pass through constness to `predicate_can_apply` and don't suggest other impls if it's satisfied but not const.
Fixes#103267
Introduce `subst_iter` and `subst_iter_copied` on `EarlyBinder`
Makes working with bounds lists a bit easier, which I seem to do a lot.
Specifically, means that we don't need to do `.transpose_iter().map(|(pred, _)| *pred)` every time we want to iterate through an `EarlyBinder<&'tcx [(Predicate, Span)]>` (and even then, still have to call `subst` later), which was a very awkward idiom imo.
Rust's niche handling allows for wrapping valid ranges with end < start;
for instance, a valid range with start=43 and end=41 means a niche of
42. Most places in the compiler handle this correctly, but
ty_find_init_error assumed that `lo > 0` means the type cannot contain a
zero.
Fix it to handle wrapping ranges.
Add a test to cover this case.
