Remove pin::Unpin reexport and add Unpin to the prelude.
Change Pin associated functions to methods.
Rename get_mut_unchecked_ to get_unchecked_mut
Remove impl Unpin for Pin
Mark Pin repr(transparent)
This lets you write methods using `self: Rc<Self>`, `self: Arc<Self>`, `self: Pin<&mut Self>`, `self: Pin<Box<Self>`, and other combinations involving `Pin` and another stdlib receiver type, without needing the `arbitrary_self_types`. Other user-created receiver types can be used, but they still require the feature flag to use.
This is implemented by introducing a new trait, `Receiver`, which the method receiver's type must implement if the `arbitrary_self_types` feature is not enabled. To keep composed receiver types such as `&Arc<Self>` unstable, the receiver type is also required to implement `Deref<Target=Self>` when the feature flag is not enabled.
This lets you use `self: Rc<Self>` and `self: Arc<Self>` in stable Rust, which was not allowed previously. It was agreed that they would be stabilized in #55786. `self: Pin<&Self>` and other pinned receiver types do not require the `arbitrary_self_types` feature, but they cannot be used on stable because `Pin` still requires the `pin` feature.
Fix grammar in compiler error for array iterators
This fixes a small grammatical mistake in the message the compiler gives when attempting to iterate directly over an array `arr` without calling `arr.iter()` or borrowing `&arr`.
Fix various aspects around `let` bindings inside const functions
* forbid `let` bindings in const contexts that use short circuiting operators
* harden analysis code against derefs of mutable references
Initially this PR was about stabilizing `let` bindings, but too many flaws were exposed that need some more testing on nightly
Remove u8 cttz hack
This issue has since been fixed in LLVM: 1886c8e29a
Furthermore this code doesn't actually work, because the 8 literal does not match the $BITS provided from the macro invocation, so effectively this was just dead code. Ref #43024.
What LLVM does is still not ideal for CPUs that only have bsf but not tzcnt, will create a patch for that later.
r? @nagisa
Documentation for impl From for AtomicBool and other Atomic types
As part of issue #51430 (cc @skade).
The impl is very simple, so not sure if we need to go into any details.
This issue has since been fixed in LLVM:
1886c8e29a
Furthermore this doesn't actually work, because the "8" literal does
not match the $BITS provided from the macro invocation, so effectively
this code was not being used anyway...
#[must_use] on traits in stdlib
Based on #55506.
Adds `#[must_use]` attribute to traits in the stdlib:
- `Iterator`
- `Future`
- `FnOnce`
- `Fn`
- `FnMut`
There may be other traits that should have the attribute, but I couldn't find/think of any.
VecDeque: fix for stacked borrows
`VecDeque` violates a version of stacked borrows where creating a shared reference is not enough to make a location *mutably accessible* from raw pointers (and I think that is the version we want). There are two problems:
* Creating a `NonNull<T>` from `&mut T` goes through `&T` (inferred for a `_`), then `*const T`, then `NonNull<T>`. That means in this stricter version of Stacked Borrows, we cannot actually write to such a `NonNull` because it was created from a shared reference! This PR fixes that by going from `&mut T` to `*mut T` to `*const T`.
* `VecDeque::drain` creates the `Drain` struct by *first* creating a `NonNull` from `self` (which is an `&mut VecDeque`), and *then* calling `self.buffer_as_mut_slice()`. The latter reborrows `self`, asserting that `self` is currently the unique pointer to access this `VecDeque`, and hence invalidating the `NonNull` that was created earlier. This PR fixes that by instead using `self.buffer_as_slice()`, which only performs read accesses and creates only shared references, meaning the raw pointer (`NonNull`) remains valid.
It is possible that other methods on `VecDeque` do something similar, miri's test coverage of `VecDeque` is sparse to say the least.
Cc @nikomatsakis @Gankro
* Update bootstrap compiler
* Update version to 1.33.0
* Remove some `#[cfg(stage0)]` annotations
Actually updating the version number is blocked on updating Cargo
Ever since we added a Cargo-based build system for the compiler the
standard library has always been a little special, it's never been able
to depend on crates.io crates for runtime dependencies. This has been a
result of various limitations, namely that Cargo doesn't understand that
crates from crates.io depend on libcore, so Cargo tries to build crates
before libcore is finished.
I had an idea this afternoon, however, which lifts the strategy
from #52919 to directly depend on crates.io crates from the standard
library. After all is said and done this removes a whopping three
submodules that we need to manage!
The basic idea here is that for any crate `std` depends on it adds an
*optional* dependency on an empty crate on crates.io, in this case named
`rustc-std-workspace-core`. This crate is overridden via `[patch]` in
this repository to point to a local crate we write, and *that* has a
`path` dependency on libcore.
Note that all `no_std` crates also depend on `compiler_builtins`, but if
we're not using submodules we can publish `compiler_builtins` to
crates.io and all crates can depend on it anyway! The basic strategy
then looks like:
* The standard library (or some transitive dep) decides to depend on a
crate `foo`.
* The standard library adds
```toml
[dependencies]
foo = { version = "0.1", features = ['rustc-dep-of-std'] }
```
* The crate `foo` has an optional dependency on `rustc-std-workspace-core`
* The crate `foo` has an optional dependency on `compiler_builtins`
* The crate `foo` has a feature `rustc-dep-of-std` which activates these
crates and any other necessary infrastructure in the crate.
A sample commit for `dlmalloc` [turns out to be quite simple][commit].
After that all `no_std` crates should largely build "as is" and still be
publishable on crates.io! Notably they should be able to continue to use
stable Rust if necessary, since the `rename-dependency` feature of Cargo
is soon stabilizing.
As a proof of concept, this commit removes the `dlmalloc`,
`libcompiler_builtins`, and `libc` submodules from this repository. Long
thorns in our side these are now gone for good and we can directly
depend on crates.io! It's hoped that in the long term we can bring in
other crates as necessary, but for now this is largely intended to
simply make it easier to manage these crates and remove submodules.
This should be a transparent non-breaking change for all users, but one
possible stickler is that this almost for sure breaks out-of-tree
`std`-building tools like `xargo` and `cargo-xbuild`. I think it should
be relatively easy to get them working, however, as all that's needed is
an entry in the `[patch]` section used to build the standard library.
Hopefully we can work with these tools to solve this problem!
[commit]: 28ee12db81
Hopefully just another routine update!
So far this starts to enable the `std::arch` in stage0 builds of rustc.
This means that we may need stage0/not(stage0) in stdsimd itself, but
more and more code is starting to use `std::arch` so I think it's time
to start shifting the balance of work here.
name old ns/iter new ns/iter diff ns/iter diff % speedup
iter::bench_cycle_take_ref_sum 927,152 927,194 42 0.00% x 1.00
iter::bench_cycle_take_sum 938,129 603,492 -334,637 -35.67% x 1.55
codegen: Fix va_list - aarch64 iOS/Windows
## Summary
Fix code generated for `VaList` on Aarch64 iOS/Windows.
## Details
According to the [Apple - ARM64 Function Calling Conventions]:
> ... the type va_list is an alias for char * rather than for the struct
> type specified in the generic PCS.
The current implementation uses the generic Aarch64 structure for `VaList`
for Aarch64 iOS. Switch to using the `char *` variant of the `VaList`
and use the corresponding `emit_ptr_va_arg` for the `va_arg` intrinsic.
Windows always uses the `char *` variant of the `VaList`. Update the `va_arg`
intrinsic to use `emit_ptr_va_arg`.
[Apple - ARM64 Function Calling Conventions]: https://developer.apple.com/library/archive/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html
According to the Apple developer docs:
> The type va_list is an alias for char * rather than for the struct
> type specified in the generic PCS.
The current implementation uses the generic Aarch64 structure for VaList
for Aarch64 iOS.
Windows always uses the char * variant of the va_list.
This commit replaces many usages of `File::open` and reading or writing
with `fs::read_to_string`, `fs::read` and `fs::write`. This reduces code
complexity, and will improve performance for most reads, since the
functions allocate the buffer to be the size of the file.
I believe that this commit will not impact behavior in any way, so some
matches will check the error kind in case the file was not valid UTF-8.
Some of these cases may not actually care about the error.
Fix a stutter in the docs for slice::exact_chunks
Before this change, the docs for `slice::exact_chunks` reads like this:
> See `chunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact` for the same iterator but starting at the end of the slice of the slice.
Notice that stutter at the end? This commit fixes it.
Introduce ptr::hash for references
The RHS is what I used, which wasn't as convenient as `ptr::eq`, so I wondered: should `ptr::hash` exist?
My first Rust PR, so I'm going to need some guidance. :)
