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Detect uninhabited types early in const eval #109435

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merged 2 commits into from
Mar 22, 2023

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oli-obk
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@oli-obk oli-obk commented Mar 21, 2023

r? @RalfJung

implements #108442 (comment)

this is a breaking change, as some UB during const eval is now detected instead of silently being ignored. Users can see this and other UB that may cause future breakage with -Zextra-const-ub-checks or just by running miri on their code, which sets that flag by default.

This is in preparation of checking the validity only of certain types.
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rustbot commented Mar 21, 2023

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @RalfJung (or someone else) soon.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

  • @rustbot author: the review is finished, PR author should check the comments and take action accordingly
  • @rustbot review: the author is ready for a review, this PR will be queued again in the reviewer's queue

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 21, 2023
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rustbot commented Mar 21, 2023

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

The Miri subtree was changed

cc @rust-lang/miri

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oli-obk commented Mar 21, 2023

@bors try @rust-timer queue

I don't expect perf to be affected, but let's check.

We need a try build for a crater run anyway

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@rustbot rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 21, 2023
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bors commented Mar 21, 2023

⌛ Trying commit 2965d7c7e4e6d6e30eae2623bfe5c5971f6fff02 with merge 8f22a9063e227203491552646fe23bfaeddd99ba...

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r=me, except -- should we be worried about the breaking aspect of this? Do we need a transition period?

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oli-obk commented Mar 21, 2023

Do we need a transition period?

no, last time we had a situation like this we concluded that having the -Z flag (and miri already setting it) is enough. If you are using unsafe code, best practices (like using miri and not transmuting to uninhabited types) should be upheld. This does not cause new silent miscompilations, just stops compiling code that was already unsound. I'll still run crater, but that doesn't take more than two days anymore nowadays.

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bors commented Mar 21, 2023

☀️ Try build successful - checks-actions
Build commit: 8f22a9063e227203491552646fe23bfaeddd99ba (8f22a9063e227203491552646fe23bfaeddd99ba)

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bors commented Mar 21, 2023

☀️ Try build successful - checks-actions
Build commit: 8f22a9063e227203491552646fe23bfaeddd99ba (8f22a9063e227203491552646fe23bfaeddd99ba)

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Finished benchmarking commit (8f22a9063e227203491552646fe23bfaeddd99ba): comparison URL.

Overall result: no relevant changes - no action needed

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

@bors rollup=never
@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)
1.6% [1.3%, 1.9%] 2
Regressions ❌
(secondary)
- - 0
Improvements ✅
(primary)
-0.5% [-0.5%, -0.5%] 1
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) 0.9% [-0.5%, 1.9%] 3

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)
- - 0
Regressions ❌
(secondary)
- - 0
Improvements ✅
(primary)
-0.4% [-0.4%, -0.4%] 1
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) -0.4% [-0.4%, -0.4%] 1

@rustbot rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Mar 21, 2023
fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks
fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>, layout: TyAndLayout<'tcx>) -> bool {
ecx.tcx.sess.opts.unstable_opts.extra_const_ub_checks || layout.abi.is_uninhabited()
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Oh, nice! That also means future PRs can easily try tuning this to catch more things where validation is cheap enough that perf says it's ok. (Like maybe checking just bool+char, or .abi.is_scalar().)

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Sadly perf being clean mostly means we don't have stress tests going through that path

@oli-obk oli-obk added the relnotes Marks issues that should be documented in the release notes of the next release. label Mar 22, 2023
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oli-obk commented Mar 22, 2023

@bors r=RalfJung

heads up @rust-lang/lang we're catching more UB at const eval time. Notably we're now rejecting the following piece of code:

#[derive(Copy, Clone)]
pub struct ChildStdin {
    inner: AnonPipe,
}
#[derive(Copy, Clone)]
enum AnonPipe {}
const FOO: () = {
    union Foo {
        a: ChildStdin,
        b: (),
    }
    let x = unsafe { Foo { b: () }.a };
};

which we accepted before, as the value x of uninhabited type was never used. We only errored on use cases.

This is not going through crater or an FCP as we already report this if the constant is used in a program checked by miri or if the user passes -Zextra-const-ub-checks. There is no warning period, as this is a very niche issue, obviously UB in other cases (using transmute instead of a union would've already errored) and would already have errored if x were used in any interesting way (so anything but taking a reference to it).

Last time we accidentally broke such a case, the verdict was that the existance of a -Z flag or miri to check for that UB is sufficient for us to break code using that UB.

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bors commented Mar 22, 2023

📌 Commit f066d67 has been approved by RalfJung

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Mar 22, 2023
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@bors rollup=maybe
perf neutral

bors added a commit to rust-lang-ci/rust that referenced this pull request Mar 22, 2023
Rollup of 11 pull requests

Successful merges:

 - rust-lang#100311 (Fix handling of trailing bare CR in str::lines)
 - rust-lang#108997 (Change text -> rust highlighting in sanitizer.md)
 - rust-lang#109179 (move Option::as_slice to intrinsic)
 - rust-lang#109187 (Render source page layout with Askama)
 - rust-lang#109280 (Remove `VecMap`)
 - rust-lang#109295 (refactor `fn bootstrap::builder::Builder::compiler_for` logic)
 - rust-lang#109312 (rustdoc: Cleanup parent module tracking for doc links)
 - rust-lang#109317 (Update links for custom discriminants.)
 - rust-lang#109405 (RPITITs are `DefKind::Opaque` with new lowering strategy)
 - rust-lang#109414 (Do not consider synthesized RPITITs on missing items checks)
 - rust-lang#109435 (Detect uninhabited types early in const eval)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit eda88a3 into rust-lang:master Mar 22, 2023
@rustbot rustbot added this to the 1.70.0 milestone Mar 22, 2023
wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request Jun 3, 2023
Pkgsrc changes:
 * Adjust patches and cargo checksums to new versions.
 * Adjust to not cross-build to 8.0, due to LLVM using c++17,
   so adjust USE_LANGUAGES.

Upstream changes:

Version 1.70.0 (2023-06-01)
==========================

Language
--------
- [Relax ordering rules for `asm!` operands]
  (rust-lang/rust#105798)
- [Properly allow macro expanded `format_args` invocations to uses
  captures] (rust-lang/rust#106505)
- [Lint ambiguous glob re-exports]
  (rust-lang/rust#107880)
- [Perform const and unsafe checking for expressions in `let _ =
  expr` position.]
  (rust-lang/rust#102256)

Compiler
--------
- [Extend -Cdebuginfo with new options and named aliases]
  (rust-lang/rust#109808)
  This provides a smaller version of debuginfo for cases that only
  need line number information (`-Cdebuginfo=line-tables-only`),
  which may eventually become the default for `-Cdebuginfo=1`.
- [Make `unused_allocation` lint against `Box::new` too]
  (rust-lang/rust#104363)
- [Detect uninhabited types early in const eval]
  (rust-lang/rust#109435)
- [Switch to LLD as default linker for {arm,thumb}v4t-none-eabi]
  (rust-lang/rust#109721)
- [Add tier 3 target `loongarch64-unknown-linux-gnu`]
  (rust-lang/rust#96971)
- [Add tier 3 target for `i586-pc-nto-qnx700` (QNX Neutrino RTOS,
  version 7.0)] (rust-lang/rust#109173),
- [Insert alignment checks for pointer dereferences as debug assertions]
  (rust-lang/rust#98112)
  This catches undefined behavior at runtime, and may cause existing
  code to fail.

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------
- [Document NonZeroXxx layout guarantees]
  (rust-lang/rust#94786)
- [Windows: make `Command` prefer non-verbatim paths]
  (rust-lang/rust#96391)
- [Implement Default for some alloc/core iterators]
  (rust-lang/rust#99929)
- [Fix handling of trailing bare CR in str::lines]
  (rust-lang/rust#100311)
- [allow negative numeric literals in `concat!`]
  (rust-lang/rust#106844)
- [Add documentation about the memory layout of `Cell`]
  (rust-lang/rust#106921)
- [Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`]
  (rust-lang/rust#108157)
- [Stabilize `atomic_as_ptr`]
  (rust-lang/rust#108419)
- [Stabilize `nonnull_slice_from_raw_parts`]
  (rust-lang/rust#97506)
- [Partial stabilization of `once_cell`]
  (rust-lang/rust#105587)
- [Stabilize `nonzero_min_max`]
  (rust-lang/rust#106633)
- [Flatten/inline format_args!() and (string and int) literal
  arguments into format_args!()]
  (rust-lang/rust#106824)
- [Stabilize movbe target feature]
  (rust-lang/rust#107711)
- [don't splice from files into pipes in io::copy]
  (rust-lang/rust#108283)
- [Add a builtin unstable `FnPtr` trait that is implemented for
  all function pointers]
  (rust-lang/rust#108080)
  This extends `Debug`, `Pointer`, `Hash`, `PartialEq`, `Eq`,
  `PartialOrd`, and `Ord` implementations for function pointers
  with all ABIs.

Stabilized APIs
---------------

- [`NonZero*::MIN/MAX`]
  (https://doc.rust-lang.org/stable/std/num/struct.NonZeroI8.html#associatedconstant.MIN)
- [`BinaryHeap::retain`]
  (https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.retain)
- [`Default for std::collections::binary_heap::IntoIter`]
  (https://doc.rust-lang.org/stable/std/collections/binary_heap/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoIter, Iter, IterMut}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoKeys, Keys}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html)
- [`Default for std::collections::btree_map::{IntoValues, Values}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html)
- [`Default for std::collections::btree_map::Range`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.Range.html)
- [`Default for std::collections::btree_set::{IntoIter, Iter}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.IntoIter.html)
- [`Default for std::collections::btree_set::Range`]
  (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.Range.html)
- [`Default for std::collections::linked_list::{IntoIter, Iter, IterMut}`]
  (https://doc.rust-lang.org/stable/alloc/collections/linked_list/struct.IntoIter.html)
- [`Default for std::vec::IntoIter`]
  (https://doc.rust-lang.org/stable/alloc/vec/struct.IntoIter.html#impl-Default-for-IntoIter%3CT,+A%3E)
- [`Default for std::iter::Chain`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Chain.html)
- [`Default for std::iter::Cloned`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Cloned.html)
- [`Default for std::iter::Copied`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Copied.html)
- [`Default for std::iter::Enumerate`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Enumerate.html)
- [`Default for std::iter::Flatten`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Flatten.html)
- [`Default for std::iter::Fuse`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Fuse.html)
- [`Default for std::iter::Rev`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Rev.html)
- [`Default for std::slice::Iter`]
  (https://doc.rust-lang.org/stable/std/slice/struct.Iter.html)
- [`Default for std::slice::IterMut`]
  (https://doc.rust-lang.org/stable/std/slice/struct.IterMut.html)
- [`Rc::into_inner`]
  (https://doc.rust-lang.org/stable/alloc/rc/struct.Rc.html#method.into_inner)
- [`Arc::into_inner`]
  (https://doc.rust-lang.org/stable/alloc/sync/struct.Arc.html#method.into_inner)
- [`std::cell::OnceCell`]
  (https://doc.rust-lang.org/stable/std/cell/struct.OnceCell.html)
- [`Option::is_some_and`]
  (https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.is_some_and)
- [`NonNull::slice_from_raw_parts`]
  (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.slice_from_raw_parts)
- [`Result::is_ok_and`]
  (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_ok_and)
- [`Result::is_err_and`]
  (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_err_and)
- [`std::sync::atomic::Atomic*::as_ptr`]
  (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicU8.html#method.as_ptr)
- [`std::io::IsTerminal`]
  (https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html)
- [`std::os::linux::net::SocketAddrExt`]
  (https://doc.rust-lang.org/stable/std/os/linux/net/trait.SocketAddrExt.html)
- [`std::os::unix::net::UnixDatagram::bind_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.bind_addr)
- [`std::os::unix::net::UnixDatagram::connect_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.connect_addr)
- [`std::os::unix::net::UnixDatagram::send_to_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.send_to_addr)
- [`std::os::unix::net::UnixListener::bind_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixListener.html#method.bind_addr)
- [`std::path::Path::as_mut_os_str`]
  (https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.as_mut_os_str)
- [`std::sync::OnceLock`]
  (https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html)

Cargo
-----

- [Add `CARGO_PKG_README`]
  (rust-lang/cargo#11645)
- [Make `sparse` the default protocol for crates.io]
  (rust-lang/cargo#11791)
- [Accurately show status when downgrading dependencies]
  (rust-lang/cargo#11839)
- [Use registry.default for login/logout]
  (rust-lang/cargo#11949)
- [Stabilize `cargo logout`]
  (rust-lang/cargo#11950)

Misc
----

- [Stabilize rustdoc `--test-run-directory`]
  (rust-lang/rust#103682)

Compatibility Notes
-------------------

- [Prevent stable `libtest` from supporting `-Zunstable-options`]
  (rust-lang/rust#109044)
- [Perform const and unsafe checking for expressions in `let _ =
  expr` position.] (rust-lang/rust#102256)
- [WebAssembly targets enable `sign-ext` and `mutable-globals`
  features in codegen] (rust-lang/rust#109807)
  This may cause incompatibility with older execution environments.
- [Insert alignment checks for pointer dereferences as debug assertions]
  (rust-lang/rust#98112)
  This catches undefined behavior at runtime, and may cause existing
  code to fail.

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.

- [Upgrade to LLVM 16]
  (rust-lang/rust#109474)
- [Use SipHash-1-3 instead of SipHash-2-4 for StableHasher]
  (rust-lang/rust#107925)
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Jul 10, 2023
Pkgsrc changes:
 * Adjust patches and cargo checksums to new versions.
 * Add support for NetBSD/riscv64.

Upstream changes:

Version 1.70.0 (2023-06-01)
==========================

Language
--------
- [Relax ordering rules for `asm!` operands]
  (rust-lang/rust#105798)
- [Properly allow macro expanded `format_args` invocations to uses captures]
  (rust-lang/rust#106505)
- [Lint ambiguous glob re-exports]
  (rust-lang/rust#107880)
- [Perform const and unsafe checking for expressions in `let _ =
  expr` position.]
  (rust-lang/rust#102256)

Compiler
--------
- [Extend -Cdebuginfo with new options and named aliases]
  (rust-lang/rust#109808)
  This provides a smaller version of debuginfo for cases that only
  need line number information (`-Cdebuginfo=line-tables-only`),
  which may eventually become the default for `-Cdebuginfo=1`.
- [Make `unused_allocation` lint against `Box::new` too]
  (rust-lang/rust#104363)
- [Detect uninhabited types early in const eval]
  (rust-lang/rust#109435)
- [Switch to LLD as default linker for {arm,thumb}v4t-none-eabi]
  (rust-lang/rust#109721)
- [Add tier 3 target `loongarch64-unknown-linux-gnu`]
  (rust-lang/rust#96971)
- [Add tier 3 target for `i586-pc-nto-qnx700`(QNX Neutrino RTOS, version 7.0)]
  (rust-lang/rust#109173),
- [Insert alignment checks for pointer dereferences as debug assertions]
  (rust-lang/rust#98112)
  This catches undefined behavior at runtime, and may cause existing
  code to fail.

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------
- [Document NonZeroXxx layout guarantees]
  (rust-lang/rust#94786)
- [Windows: make `Command` prefer non-verbatim paths]
  (rust-lang/rust#96391)
- [Implement Default for some alloc/core iterators]
  (rust-lang/rust#99929)
- [Fix handling of trailing bare CR in str::lines]
  (rust-lang/rust#100311)
- [allow negative numeric literals in `concat!`]
  (rust-lang/rust#106844)
- [Add documentation about the memory layout of `Cell`]
  (rust-lang/rust#106921)
- [Use `partial_cmp` to implement tuple `lt`/`le`/`ge`/`gt`]
  (rust-lang/rust#108157)
- [Stabilize `atomic_as_ptr`]
  (rust-lang/rust#108419)
- [Stabilize `nonnull_slice_from_raw_parts`]
  (rust-lang/rust#97506)
- [Partial stabilization of `once_cell`]
  (rust-lang/rust#105587)
- [Stabilize `nonzero_min_max`]
  (rust-lang/rust#106633)
- [Flatten/inline format_args!() and (string and int) literal
  arguments into format_args!()]
  (rust-lang/rust#106824)
- [Stabilize movbe target feature]
  (rust-lang/rust#107711)
- [don't splice from files into pipes in io::copy]
  (rust-lang/rust#108283)
- [Add a builtin unstable `FnPtr` trait that is implemented for
  all function pointers]
  (rust-lang/rust#108080)
  This extends `Debug`, `Pointer`, `Hash`, `PartialEq`, `Eq`,
  `PartialOrd`, and `Ord` implementations for function pointers
  with all ABIs.


Stabilized APIs
---------------

- [`NonZero*::MIN/MAX`]
  (https://doc.rust-lang.org/stable/std/num/struct.NonZeroI8.html#associatedconstant.MIN)
- [`BinaryHeap::retain`]
  (https://doc.rust-lang.org/stable/std/collections/struct.BinaryHeap.html#method.retain)
- [`Default for std::collections::binary_heap::IntoIter`]
  (https://doc.rust-lang.org/stable/std/collections/binary_heap/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoIter, Iter, IterMut}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoIter.html)
- [`Default for std::collections::btree_map::{IntoKeys, Keys}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html)
- [`Default for std::collections::btree_map::{IntoValues, Values}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.IntoKeys.html)
- [`Default for std::collections::btree_map::Range`]
  (https://doc.rust-lang.org/stable/std/collections/btree_map/struct.Range.html)
- [`Default for std::collections::btree_set::{IntoIter, Iter}`]
  (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.IntoIter.html)
- [`Default for std::collections::btree_set::Range`]
  (https://doc.rust-lang.org/stable/std/collections/btree_set/struct.Range.html)
- [`Default for std::collections::linked_list::{IntoIter, Iter, IterMut}`]
  (https://doc.rust-lang.org/stable/alloc/collections/linked_list/struct.IntoIter.html)
- [`Default for std::vec::IntoIter`]
  (https://doc.rust-lang.org/stable/alloc/vec/struct.IntoIter.html#impl-Default-for-IntoIter%3CT,+A%3E)
- [`Default for std::iter::Chain`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Chain.html)
- [`Default for std::iter::Cloned`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Cloned.html)
- [`Default for std::iter::Copied`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Copied.html)
- [`Default for std::iter::Enumerate`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Enumerate.html)
- [`Default for std::iter::Flatten`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Flatten.html)
- [`Default for std::iter::Fuse`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Fuse.html)
- [`Default for std::iter::Rev`]
  (https://doc.rust-lang.org/stable/std/iter/struct.Rev.html)
- [`Default for std::slice::Iter`]
  (https://doc.rust-lang.org/stable/std/slice/struct.Iter.html)
- [`Default for std::slice::IterMut`]
  (https://doc.rust-lang.org/stable/std/slice/struct.IterMut.html)
- [`Rc::into_inner`]
  (https://doc.rust-lang.org/stable/alloc/rc/struct.Rc.html#method.into_inner)
- [`Arc::into_inner`]
  (https://doc.rust-lang.org/stable/alloc/sync/struct.Arc.html#method.into_inner)
- [`std::cell::OnceCell`]
  (https://doc.rust-lang.org/stable/std/cell/struct.OnceCell.html)
- [`Option::is_some_and`]
  (https://doc.rust-lang.org/stable/std/option/enum.Option.html#method.is_some_and)
- [`NonNull::slice_from_raw_parts`]
  (https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.slice_from_raw_parts)
- [`Result::is_ok_and`]
  (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_ok_and)
- [`Result::is_err_and`]
  (https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.is_err_and)
- [`std::sync::atomic::Atomic*::as_ptr`]
  (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicU8.html#method.as_ptr)
- [`std::io::IsTerminal`]
  (https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html)
- [`std::os::linux::net::SocketAddrExt`]
  (https://doc.rust-lang.org/stable/std/os/linux/net/trait.SocketAddrExt.html)
- [`std::os::unix::net::UnixDatagram::bind_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.bind_addr)
- [`std::os::unix::net::UnixDatagram::connect_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.connect_addr)
- [`std::os::unix::net::UnixDatagram::send_to_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixDatagram.html#method.send_to_addr)
- [`std::os::unix::net::UnixListener::bind_addr`]
  (https://doc.rust-lang.org/stable/std/os/unix/net/struct.UnixListener.html#method.bind_addr)
- [`std::path::Path::as_mut_os_str`]
  (https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.as_mut_os_str)
- [`std::sync::OnceLock`]
  (https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html)

Cargo
-----

- [Add `CARGO_PKG_README`]
  (rust-lang/cargo#11645)
- [Make `sparse` the default protocol for crates.io]
  (rust-lang/cargo#11791)
- [Accurately show status when downgrading dependencies]
  (rust-lang/cargo#11839)
- [Use registry.default for login/logout]
  (rust-lang/cargo#11949)
- [Stabilize `cargo logout`]
  (rust-lang/cargo#11950)

Misc
----

- [Stabilize rustdoc `--test-run-directory`]
  (rust-lang/rust#103682)

Compatibility Notes
-------------------

- [Prevent stable `libtest` from supporting `-Zunstable-options`]
  (rust-lang/rust#109044)
- [Perform const and unsafe checking for expressions in `let _ =
  expr` position.]
  (rust-lang/rust#102256)
- [WebAssembly targets enable `sign-ext` and `mutable-globals`
  features in codegen]
  (rust-lang/rust#109807)
  This may cause incompatibility with older execution environments.
- [Insert alignment checks for pointer dereferences as debug assertions]
  (rust-lang/rust#98112)
  This catches undefined behavior at runtime, and may cause existing
  code to fail.

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.

- [Upgrade to LLVM 16]
  (rust-lang/rust#109474)
- [Use SipHash-1-3 instead of SipHash-2-4 for StableHasher]
  (rust-lang/rust#107925)
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