library/std: Remove unused `gimli-symbolize` feature
library/backtrace also declares a feature called `gimli-symbolize` which appear used, but the feature in std with the same name is unused, so remove it.
String.truncate comment microfix (greater or equal)
String.truncate calls Vec.truncate, in turn, and that states "is greater or equal to". Beside common sense.
deref patterns: impl `DerefPure` for more std types
Context: [deref patterns](https://github.com/rust-lang/rust/issues/87121). The requirements of `DerefPure` aren't precise yet, but these types unambiguously satisfy them.
Interestingly, a hypothetical `impl DerefMut for Cow` that does a `Clone` would *not* be eligible for `DerefPure` if we allow mixing deref patterns with normal patterns. If the following is exhaustive then the `DerefMut` would cause UB:
```rust
match &mut Cow::Borrowed(&()) {
Cow::Owned(_) => ..., // Doesn't match
deref!(_x) if false => ..., // Causes the variant to switch to `Owned`
Cow::Borrowed(_) => ..., // Doesn't match
// We reach unreachable
}
```
In the stabilization attempt of `#[unix_sigpipe = "sig_dfl"]`, a concern
was raised related to using a language attribute for the feature: Long
term, we want `fn lang_start()` to be definable by any crate, not just
libstd. Having a special language attribute in that case becomes
awkward.
So as a first step towards towards the next stabilization attempt, this
PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag
`-Zon-broken-pipe=...` to remove that concern, since now the language
is not "contaminated" by this feature.
Another point was also raised, namely that the ui should not leak
**how** it does things, but rather what the **end effect** is. The new
flag uses the proposed naming. This is of course something that can be
iterated on further before stabilization.
Document never type fallback in `!`'s docs
Pulled the documentation I've written for #123939.
I want a single place where never type fallback is explained, which can be referred in all the lints and migration materials.
library/backtrace also declares a feature called `gimli-symbolize` which
appear used, but the feature in std with the same name is unused, so
remove it.
Use `target_vendor = "apple"` instead of `target_os = "..."`
Use `target_vendor = "apple"` instead of `all(target_os = "macos", target_os = "ios", target_os = "tvos", target_os = "watchos", target_os = "visionos")`.
The apple targets are quite close to being identical, with iOS, tvOS, watchOS and visionOS being even closer, so using `target_vendor` when possible makes it clearer when something is actually OS-specific, or just Apple-specific.
Note that `target_vendor` will [be deprecated in the future](https://github.com/rust-lang/rust/issues/100343), but not before an alternative (like `target_family = "apple"`) is available.
While doing this, I found various inconsistencies and small mistakes in the standard library, see the commits for details. Will follow-up with an extra PR for a similar issue that need a bit more discussion. EDIT: https://github.com/rust-lang/rust/pull/124494
Since you've talked about using `target_vendor = "apple"` in the past:
r? workingjubilee
CC `@simlay,` `@thomcc`
`@rustbot` label O-macos O-ios O-tvos O-watchos O-visionos
Fix#124478 - offset_of! returns a temporary
This was due to the must_use() call. Adding HIR's `OffsetOf` to the must_use checking within the compiler avoids this issue while maintaining the lint output.
Fixes#124478. `@tgross35`
Update `is_val_statically_known` Docs
* Add `Type Requirements` section, listing the allowed inputs, as requested by #121115
* Add `Pointers` subsection, explaining is_val_statically_known handles pointers.
* Add `Stability concerns` section, referring to other documentation relating to consistency in `const` functions.
Fixes#121115
Sorry this took so long.
`man posix_spawn` documents it to be able to return `ENOENT`, and there
should be nothing preventing this. Tested in the iOS simulator and on
Mac Catalyst.
Abort a process when FD ownership is violated
When an owned FD has already been closed before it's dropped that means something else touched an FD in ways it is not allowed to. At that point things can already be arbitrarily bad, e.g. clobbered mmaps. Recovery is not possible.
All we can do is hasten the fire.
Unlike the previous attempt in #124130 this shouldn't suffer from the possibility that FUSE filesystems can return arbitrary errors.
Unconditionally call `really_init` on GNU/Linux
This makes miri not diverge in behavior, it fixes running Rust linux-gnu binaries on musl with gcompat, it fixes dlopen edge-cases that cranelift somehow hits, etc.
Fixes#124126
thou hast gazed into this abyss with me:
r? ``@ChrisDenton``
This makes miri not diverge in behavior, it fixes running Rust linux-gnu
binaries on musl with gcompat, it fixes dlopen edge-cases that cranelift
somehow hits, etc.
thread_local: be excruciatingly explicit in dtor code
Use raw pointers to accomplish internal mutability, and clearly split references where applicable. This reduces the likelihood that any of these parts are misunderstood, either by humans or the compiler's optimizations.
Fixes#124317
r? ``@joboet``
PathBuf: replace transmuting by accessor functions
The existing `repr(transparent)` was anyway insufficient as `OsString` was not `repr(transparent)`. And furthermore, on Windows it was blatantly wrong as `OsString` wraps `Wtf8Buf` which is a `repr(Rust)` type with 2 fields:
51a7396ad3/library/std/src/sys_common/wtf8.rs (L131-L146)
So let's just be honest about what happens and add accessor methods that make this abstraction-breaking act of PathBuf visible on the APIs that it pierces through.
Fixes https://github.com/rust-lang/rust/issues/124409
Convert some iter macros to normal functions
With all the MIR optimization changes that have happened since these were written, let's see if they still actually matter.
\*perf comes back\*
Well, it looks like it's not longer relevant for instruction, cycle, nor wall-time perf. Looks like a bunch of things are maybe 10kb bigger in debug, but some are also 50k *smaller* in debug.
So I think they should switch to being normal functions as the "greatly improves performance" justification for them being macros seems to no longer be true -- probably thanks to us always building `core` with `-Z inline-mir` so the difference is negligible.
Add diagnostic item for `std::iter::Enumerate`
This adds a diagnostic item for `std::iter::Enumerate`. The change will be used by the clippy `unused_enumerate_index` lint to move away from type paths to using diagnostic items.
see: https://github.com/rust-lang/rust-clippy/issues/5393
windows fill_utf16_buf: explain the expected return value
The comment just says "return what the syscall returns", but that doesn't work for all syscalls as the Windows API is not consistent in how buffer size is negotiated. For instance, GetUserProfileDirectoryW works a bit differently, and so home_dir_crt has to translate this to the usual protocol itself. So it's worth describing that protocol.
r? ``@ChrisDenton``
Rollup of 3 pull requests
Successful merges:
- #124003 (Dellvmize some intrinsics (use `u32` instead of `Self` in some integer intrinsics))
- #124169 (Don't fatal when calling `expect_one_of` when recovering arg in `parse_seq`)
- #124286 (Subtree sync for rustc_codegen_cranelift)
r? `@ghost`
`@rustbot` modify labels: rollup
Dellvmize some intrinsics (use `u32` instead of `Self` in some integer intrinsics)
This implements https://github.com/rust-lang/compiler-team/issues/693 minus what was implemented in #123226.
Note: I decided to _not_ change `shl`/... builder methods, as it just doesn't seem worth it.
r? ``@scottmcm``
alloc::Layout: explicitly document size invariant on the type level
https://github.com/rust-lang/rust/pull/95295 added this to the constructor, but it seems worth documenting the type invariant at the type level.
panic_str only exists for the migration to 2021 panic macros
The only caller is `expect_failed`, which is already a cold inline(never) function, so inlining into that function should be fine. (And indeed `panic_str` was `#[inline]` anyway.)
The existence of panic_str risks someone calling it when they should call `panic` instead, and I can't see a reason why this footgun should exist.
I also extended the comment in `panic` to explain why it needs a `'static` string -- I know I've wondered about this in the past and it took me quite a while to understand.
remove an unused type from the reentrant lock tests
At least it seems unused. This was added back in 45aa6c8d1b together with a test related to poisoning; when the test got removed, it seems like it was forgotten to also remove this type.
Add simple async drop glue generation
This is a prototype of the async drop glue generation for some simple types. Async drop glue is intended to behave very similar to the regular drop glue except for being asynchronous. Currently it does not execute synchronous drops but only calls user implementations of `AsyncDrop::async_drop` associative function and awaits the returned future. It is not complete as it only recurses into arrays, slices, tuples, and structs and does not have same sensible restrictions as the old `Drop` trait implementation like having the same bounds as the type definition, while code assumes their existence (requires a future work).
This current design uses a workaround as it does not create any custom async destructor state machine types for ADTs, but instead uses types defined in the std library called future combinators (deferred_async_drop, chain, ready_unit).
Also I recommend reading my [explainer](https://zetanumbers.github.io/book/async-drop-design.html).
This is a part of the [MCP: Low level components for async drop](https://github.com/rust-lang/compiler-team/issues/727) work.
Feature completeness:
- [x] `AsyncDrop` trait
- [ ] `async_drop_in_place_raw`/async drop glue generation support for
- [x] Trivially destructible types (integers, bools, floats, string slices, pointers, references, etc.)
- [x] Arrays and slices (array pointer is unsized into slice pointer)
- [x] ADTs (enums, structs, unions)
- [x] tuple-like types (tuples, closures)
- [ ] Dynamic types (`dyn Trait`, see explainer's [proposed design](https://github.com/zetanumbers/posts/blob/main/async-drop-design.md#async-drop-glue-for-dyn-trait))
- [ ] coroutines (https://github.com/rust-lang/rust/pull/123948)
- [x] Async drop glue includes sync drop glue code
- [x] Cleanup branch generation for `async_drop_in_place_raw`
- [ ] Union rejects non-trivially async destructible fields
- [ ] `AsyncDrop` implementation requires same bounds as type definition
- [ ] Skip trivially destructible fields (optimization)
- [ ] New [`TyKind::AdtAsyncDestructor`](https://github.com/zetanumbers/posts/blob/main/async-drop-design.md#adt-async-destructor-types) and get rid of combinators
- [ ] [Synchronously undroppable types](https://github.com/zetanumbers/posts/blob/main/async-drop-design.md#exclusively-async-drop)
- [ ] Automatic async drop at the end of the scope in async context
checked_ilog: improve performance
Addresses #115874.
(This PR replicates the original #115875, which I accidentally closed by deleting my forked repository...)
Oli Scherer