Add `AsyncFn*` to the prelude in all editions
The general vibe is that we will most likely stabilize the `feature(async_closure)` *without* the `async Fn()` trait bound modifier.
Without `async Fn()` bound syntax, this necessitates users to spell the bound like `AsyncFn()`. Since `core::ops::AsyncFn` is not in the prelude, users will need to import these any time they actually want to use the trait. This seems annoying, so let's add these traits to the prelude unstably.
We're trying to work on the general vision of `async` trait bound modifier in general in: https://github.com/rust-lang/rfcs/pull/3710, however that RFC still needs more time for consensus to converge, and we've decided that the value that users get from calling the bound `async Fn()` is *not really* worth blocking landing async closures in general.
btree: don't leak value if destructor of key panics
This PR fixes a regression from https://github.com/rust-lang/rust/pull/84904.
The `BTreeMap` already attempts to handle panicking destructors of the key-value pairs by continuing to execute the remaining destructors after one destructor panicked. However, after #84904 the destructor of a value in a key-value pair gets skipped if the destructor of the key panics, only continuing with the next key-value pair. This PR reverts to the behavior before #84904 to also drop the corresponding value if the destructor of a key panics.
This avoids potential memory leaks and can fix the soundness of programs that rely on the destructors being executed (even though this should not be relied upon, because the std collections currently do not guarantee that the remaining elements are dropped after a panic in a destructor).
cc `@Amanieu` because you had opinions on panicking destructors
Rollup of 6 pull requests
Successful merges:
- #127483 (Allow disabling ASan instrumentation for globals)
- #131505 (use `confstr(_CS_DARWIN_USER_TEMP_DIR, ...)` as a `TMPDIR` fallback on Darwin)
- #132949 (Add specific diagnostic for using macro_rules macro as attribute/derive)
- #133286 (Re-delay a resolve `bug` related to `Self`-ctor in patterns)
- #133332 (Mark `<[T; N]>::as_mut_slice` with the `const` specifier.)
- #133366 (Remove unnecessary bool from `ExpectedFound::new`)
r? `@ghost`
`@rustbot` modify labels: rollup
Minimally constify `Add`
* This PR removes the requirement for `impl const` to have a const stability attribute. cc ``@RalfJung`` I believe you mentioned that it would make much more sense to require `const_trait`s to have const stability instead. I agree with that sentiment but I don't think that is _required_ for a small scale experimentation like this PR. https://github.com/rust-lang/project-const-traits/issues/16 should definitely be prioritized in the future, but removing the impl check should be good for now as all callers need `const_trait_impl` enabled for any const impl to work.
* This PR is intentionally minimal as constifying other traits can become more complicated (`PartialEq`, for example, would run into requiring implementing it for `str` as that is used in matches, which runs into the implementation for slice equality which uses specialization)
Per the reasons above, anyone who is interested in making traits `const` in the standard library are **strongly encouraged** to reach out to us on the [Zulip channel](https://rust-lang.zulipchat.com/#narrow/channel/419616-t-compiler.2Fproject-const-traits) before proceeding with the work.
cc ``@rust-lang/project-const-traits``
I believe there is prior approval from libs that we can experiment, so
r? project-const-traits
Mark `<[T; N]>::as_mut_slice` with the `const` specifier.
Tracking issue: #133333
`<[T; N]>::as_mut_slice` can have the `const` specifier without any changes to the function body.
Rollup of 8 pull requests
Successful merges:
- #132090 (Stop being so bail-y in candidate assembly)
- #132658 (Detect const in pattern with typo)
- #132911 (Pretty print async fn sugar in opaques and trait bounds)
- #133102 (aarch64 softfloat target: always pass floats in int registers)
- #133159 (Don't allow `-Zunstable-options` to take a value )
- #133208 (generate-copyright: Now generates a library file too.)
- #133215 (Fix missing submodule in `./x vendor`)
- #133264 (implement OsString::truncate)
r? `@ghost`
`@rustbot` modify labels: rollup
Implement `~const Destruct` effect goal in the new solver
This also fixed a subtle bug/limitation of the `NeedsConstDrop` check. Specifically, the "`Qualif`" API basically treats const drops as totally structural, even though dropping something that has an explicit `Drop` implementation cannot be structurally decomposed. For example:
```rust
#![feature(const_trait_impl)]
#[const_trait] trait Foo {
fn foo();
}
struct Conditional<T: Foo>(T);
impl Foo for () {
fn foo() {
println!("uh oh");
}
}
impl<T> const Drop for Conditional<T> where T: ~const Foo {
fn drop(&mut self) {
T::foo();
}
}
const FOO: () = {
let _ = Conditional(());
//~^ This should error.
};
fn main() {}
```
In this example, when checking if the `Conditional(())` rvalue is const-drop, since `Conditional` has a const destructor, we would previously recurse into the `()` value and determine it has nothing to drop, which means that it is considered to *not* need a const drop -- even though dropping `Conditional(())` would mean evaluating the destructor which relies on that `T: const Foo` bound to hold!
This could be fixed alternatively by banning any const conditions on `const Drop` impls, but that really sucks -- that means that basically no *interesting* const drop impls could be written. We have the capability to totally and intuitively support the right behavior, which I've implemented here.
Rollup of 8 pull requests
Successful merges:
- #133238 (re-export `is_loongarch_feature_detected`)
- #133288 (Support `each_ref` and `each_mut` in `[T; N]` in constant expressions.)
- #133311 (Miri subtree update)
- #133313 (Use arc4random of libc for RTEMS target)
- #133319 (Simplify `fulfill_implication`)
- #133323 (Bail in effects in old solver if self ty is ty var)
- #133330 (library: update comment around close())
- #133337 (Fix typo in `std:🧵:Scope::spawn` documentation.)
r? `@ghost`
`@rustbot` modify labels: rollup
Support `each_ref` and `each_mut` in `[T; N]` in constant expressions.
Tracking issue: #133289
The methods `<[T; N]>::each_ref` and `<[T; N]>::each_mut` can easily be reimplemented to allow marking them with the `const` specifier.
This specific implementation takes a different approach than the original as to avoid using iterators (which are illegal in constant expressions).
Stabilize `Ipv6Addr::is_unique_local` and `Ipv6Addr::is_unicast_link_local`
Make `Ipv6Addr::is_unique_local` and `Ipv6Addr::is_unicast_link_local` stable (+const).
Newly stable API:
```rust
impl Ipv6Addr {
// Newly stable under `ipv6_is_unique_local`
const fn is_unique_local(&self) -> bool;
// Newly stable under `ipv6_is_unique_local`
const fn is_unicast_link_local(&self) -> bool;
}
```
These stabilise a subset of the following tracking issue:
- #27709
I have looked and could not find any issues with `is_unique_local` and `is_unicast_link_local`. There is a well received comment calling for stabilisation of the latter function.
Both functions are well defined and consistent with implementations in other languages:
- [Go](https://cs.opensource.google/go/go/+/refs/tags/go1.23.0:src/net/netip/netip.go;l=518)
- [Python](e9d1bf353c/Lib/ipaddress.py (L2319-L2321))
- [Ruby (unique local)](https://ruby-doc.org/stdlib-2.5.1/libdoc/ipaddr/rdoc/IPAddr.html#private-3F-source)
- [Ruby (unicast link local)](https://ruby-doc.org/stdlib-2.5.1/libdoc/ipaddr/rdoc/IPAddr.html#link_local-3F-source)
cc implementor `@little-dude`
(I can't find the original PR for `is_unqiue_local`)
r? libs-api
`@rustbot` label +T-libs-api +needs-fcp
Emscripten: link with -sWASM_BIGINT
When linking an executable without dynamic linking, this is a pure improvement. It significantly reduces code size and avoids a lot of buggy behaviors. It is supported in all browsers for many years and in all maintained versions of Node.
It does change the ABI, so people who are dynamically linking with a library or executable that uses the old ABI may need to turn it off. It can be disabled if needed by passing `-Clink-arg -sWASM_BIGINT=0` to `rustc`. But few people will want to turn it off.
Note this includes a libc bump to 0.2.162!
Make `PointerLike` opt-in instead of built-in
The `PointerLike` trait currently is a built-in trait that computes the layout of the type. This is a bit problematic, because types implement this trait automatically. Since this can be broken due to semver-compatible changes to a type's layout, this is undesirable. Also, calling `layout_of` in the trait system also causes cycles.
This PR makes the trait implemented via regular impls, and adds additional validation on top to make sure that those impls are valid. This could eventually be `derive()`d for custom smart pointers, and we can trust *that* as a semver promise rather than risking library authors accidentally breaking it.
On the other hand, we may never expose `PointerLike`, but at least now the implementation doesn't invoke `layout_of` which could cause ICEs or cause cycles.
Right now for a `PointerLike` impl to be valid, it must be an ADT that is `repr(transparent)` and the non-1zst field needs to implement `PointerLike`. There are also some primitive impls for `&T`/ `&mut T`/`*const T`/`*mut T`/`Box<T>`.
Mark `get_mut` and `set_position` in `std::io::Cursor` as const.
Relevant tracking issue: #130801
The methods `get_mut` and `set_position` can trivially be marked as const due to #57349 being stabilised.
Use attributes for `dangling_pointers_from_temporaries` lint
Checking for dangling pointers by function name isn't ideal, and leaves out certain pointer-returning methods that don't follow the `as_ptr` naming convention. Using an attribute for this lint cleans things up and allows more thorough coverage of other methods, such as `UnsafeCell::get()`.
Add vec_deque::Iter::as_slices and friends
Add the following methods, that work similarly to VecDeque::as_slices:
- alloc::collections::vec_deque::Iter::as_slices
- alloc::collections::vec_deque::IterMut::into_slices
- alloc::collections::vec_deque::IterMut::as_slices
- alloc::collections::vec_deque::IterMut::as_mut_slices
Obtaining slices from a VecDeque iterator was not previously possible.
