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Warn when a #[test]-like built-in attribute macro is present multiple times. #91172

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merged 1 commit into from
Dec 17, 2021

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Ethiraric
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Fixes #90979.

@GuillaumeGomez
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r? @petrochenkov

@Milo123459
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Shouldn't this emit an error, not a warning? I'm trying to think of a use case where having multiple #[test]'s is a good idea and would probably make sense for it to be an error. Just giving my opinion though, it might make sense to have it as a warning.

@Ethiraric
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It could very well be an error. I don't see any case either where this would be the expected behavior. Having a hard error on that is maybe too inconvenient on what was probably an oversight from the developer and could break existing codebases.

@Milo123459
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It could very well be an error. I don't see any case either where this would be the expected behavior. Having a hard error on that is maybe too inconvenient on what was probably an oversight from the developer and could break existing codebases.

Implementing a fix for it would be super easy; it just has to remove the other usages of #[test] on that function.

@Ethiraric
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How does that weigh in whether this should be an error or a warning?

@GuillaumeGomez
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It's up to @rust-lang/compiler team I guess. But in any case, I think we have to first start with a warning saying it'll become a hard error in the future if we decide that it's not supposed to compile.

@Milo123459
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How does that weigh in whether this should be an error or a warning?

Read it wrong. My bad.

I agree - throwing a hard error might be inconsistent.

@lcnr
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lcnr commented Nov 24, 2021

we currently allow the following without any warnings as well

#[inline]
#[inline]
fn foo() {}

I think that ideally we should hard error for duplicate builtin attributes though starting with a future incompat lint is probably the right choice 🤔 imo we should start a crater run for this, you would have to first convert the warning to an error in that case.

@nagisa
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nagisa commented Nov 24, 2021

Right now the story around duplicate attributes is definitely somewhat erratic. There are some attributes which when duplicated will implement their function twice and sometimes cause an error (though outside of the attribute system). derive and test are an example of this. Some others will behave as if the attribute was specified once (e.g. #[no_mangle]), and some, such as inline will have an overriding behaviour (where only the last applies).

To be fair, I'm not sure if test having the “repeated operation” is the right model for #[test] in the first place – I would've expected it to work more like no_mangle, in which case warning would not be necessary either.

There are also considerations with regards to e.g. macros, where ability to duplicate some attributes may make things significantly easier for them.

@GuillaumeGomez
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There are also considerations with regards to e.g. macros, where ability to duplicate some attributes may make things significantly easier for them.

This is mostly why I think a warning should be enough.

@Ethiraric
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you would have to first convert the warning to an error in that case.

As implemented in this PR, the diagnostic is reported as a warning.

Should you decide on what the behavior for repeated builtin attributes should be, I am willing, in other PRs, to change their behaviors according to what you think is best.

In any case, let me know what changes you want me to do in this PR.

@petrochenkov petrochenkov added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Nov 24, 2021
@jyn514 jyn514 added A-attributes Area: Attributes (`#[…]`, `#![…]`) T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Nov 24, 2021
@ehuss
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ehuss commented Nov 24, 2021

we currently allow the following without any warnings as well

Duplicate attributes should now warn on the latest nightly.

@Ethiraric
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Duplicate attributes should now warn on the latest nightly.

It doesn't as of :

rustc 1.58.0-nightly (65c55bf93 2021-11-23)
binary: rustc
commit-hash: 65c55bf931a55e6b1e5ed14ad8623814a7386424
commit-date: 2021-11-23
host: x86_64-unknown-linux-gnu
release: 1.58.0-nightly
LLVM version: 13.0.0

@ehuss
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ehuss commented Nov 24, 2021

@Ethiraric Can you say more about what you tried? It should display a warning like this:

warning: unused attribute
 --> src/lib.rs:2:1
  |
2 | #[inline]
  | ^^^^^^^^^ help: remove this attribute
  |
  = note: `#[warn(unused_attributes)]` on by default
note: attribute also specified here
 --> src/lib.rs:1:1
  |
1 | #[inline]
  | ^^^^^^^^^
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!

If you tried with #[test], then that is because the lint intentionally doesn't fire on proc-macros.

@Ethiraric
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Ethiraric commented Nov 24, 2021

I tried to compile the file I linked on the issue with the compiler I posted the version of.

Can you try to compile the snippet from #90979 and tell me whether you have a warning?

EDIT: Sorry, hadn't noticed the last line after the snippet.
Why is that that #[test] doesn't show any diagnostic?

@ehuss
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ehuss commented Nov 24, 2021

Why is that that #[test] doesn't show any diagnostic?

#[test] is treated like a proc-macro, and not a built-in attribute. The lint only fires for built-in attributes.

@Ethiraric
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But, with the current behaviour, I don't see any case annotating an item more than once with #[test] would be desired. This is why I thought a warn (not a hard error) would be nice.

I get that because it's a particular macro there currently is no warn. I have implemented this diagnostic here because I think there should be at least something that warns user.

Do you think this would be a bad addition?

@GuillaumeGomez
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I think the same as @Ethiraric in here: having a test run as many times as the #[test] attribute is present deserves at least a warning so at least you know why it's happening (even more if it comes from a macro!).

@ehuss
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ehuss commented Nov 24, 2021

Sorry, I didn't mean to mislead. I wasn't advocating against this change. I was just pointing out in the discussion above that things had changed (for built-in attribute) as of 2 days ago, and people didn't seem to be aware.

@GuillaumeGomez
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Funny that @Ethiraric came across this just in the middle of this "change wave". :)

@petrochenkov
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petrochenkov commented Nov 25, 2021

The full list of test-like built-in attribute macros is cfg_eval, global_allocator, test_case, test and bench.
They should all behave in the same way with regards to duplicates.
(They can be found by searching for calls to check_builtin_macro_attribute.)

@petrochenkov petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 25, 2021
@Ethiraric
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Thank you for your review and pointers. Should I add the lint to all built-in attribute macros in this PR or open a new one?

@Ethiraric
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Updated the comment for the lint.

I think however the build fails because the snippet of code should be run with --test. I know not how to instruct the compiler to do so.

@petrochenkov petrochenkov added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Dec 15, 2021
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@petrochenkov
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petrochenkov commented Dec 15, 2021

I think however the build fails because the snippet of code should be run with --test. I know not how to instruct the compiler to do so.

You can use

```rust,ignore

for disabling the lint-docs check.

@petrochenkov petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 15, 2021
@Ethiraric
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Thanks for your review. I should have fixed all your requested changes!

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@petrochenkov petrochenkov added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Dec 16, 2021
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@bors r+

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bors commented Dec 16, 2021

📌 Commit 2be94d4 has been approved by petrochenkov

@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 Dec 16, 2021
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request Dec 16, 2021
…rochenkov

Warn when a `#[test]`-like built-in attribute macro is present multiple times.

Fixes rust-lang#90979.
bors added a commit to rust-lang-ci/rust that referenced this pull request Dec 16, 2021
…askrgr

Rollup of 7 pull requests

Successful merges:

 - rust-lang#91172 (Warn when a `#[test]`-like built-in attribute macro is present multiple times.)
 - rust-lang#91796 (Fix since attribute for const_manually_drop feature)
 - rust-lang#91879 (Remove `in_band_lifetimes` from `rustc_borrowck`)
 - rust-lang#91947 (Add `io::Error::other`)
 - rust-lang#91967 (Pull in libdevstat on FreeBSD)
 - rust-lang#91987 (Add module documentation for rustdoc passes)
 - rust-lang#92001 (Fix default_method_body_is_const when used across crates)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 7407c4e into rust-lang:master Dec 17, 2021
@rustbot rustbot added this to the 1.59.0 milestone Dec 17, 2021
wip-sync pushed a commit to NetBSD/pkgsrc-wip that referenced this pull request Mar 2, 2022
Pkgsrc changes:
 * Bump available bootstraps to 1.58.1.
 * Adjust one patch (and checksum) so that it still applies.

Upstream changes:

Version 1.59.0 (2022-02-24)
==========================

Language
--------

- [Stabilize default arguments for const generics][90207]
- [Stabilize destructuring assignment][90521]
- [Relax private in public lint on generic bounds and where clauses
  of trait impls][90586]
- [Stabilize asm! and global_asm! for x86, x86_64, ARM, Aarch64,
  and RISC-V][91728]

Compiler
--------

- [Stabilize new symbol mangling format, leaving it opt-in
  (-Csymbol-mangling-version=v0)][90128]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Fix sparc64 ABI for aggregates with floating point members][91003]
- [Warn when a `#[test]`-like built-in attribute macro is present
  multiple times.][91172]
- [Add support for riscv64gc-unknown-freebsd][91284]
- [Stabilize `-Z emit-future-incompat` as `--json future-incompat`][91535]
- [Soft disable incremental compilation][94124]

This release disables incremental compilation, unless the user has explicitly
opted in via the newly added RUSTC_FORCE_INCREMENTAL=1 environment variable.
This is due to a known and relatively frequently occurring bug in incremental
compilation, which causes builds to issue internal compiler errors. This
particular bug is already fixed on nightly, but that fix has not yet rolled out
to stable and is deemed too risky for a direct stable backport.

As always, we encourage users to test with nightly and report bugs so that we
can track failures and fix issues earlier.

See [94124] for more details.

[94124]: rust-lang/rust#94124

Libraries
---------

- [Remove unnecessary bounds for some Hash{Map,Set} methods][91593]

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

- [`std::thread::available_parallelism`][available_parallelism]
- [`Result::copied`][result-copied]
- [`Result::cloned`][result-cloned]
- [`arch::asm!`][asm]
- [`arch::global_asm!`][global_asm]
- [`ops::ControlFlow::is_break`][is_break]
- [`ops::ControlFlow::is_continue`][is_continue]
- [`TryFrom<char> for u8`][try_from_char_u8]
- [`char::TryFromCharError`][try_from_char_err]
  implementing `Clone`, `Debug`, `Display`, `PartialEq`, `Copy`, `Eq`, `Error`
- [`iter::zip`][zip]
- [`NonZeroU8::is_power_of_two`][is_power_of_two8]
- [`NonZeroU16::is_power_of_two`][is_power_of_two16]
- [`NonZeroU32::is_power_of_two`][is_power_of_two32]
- [`NonZeroU64::is_power_of_two`][is_power_of_two64]
- [`NonZeroU128::is_power_of_two`][is_power_of_two128]
- [`DoubleEndedIterator for ToLowercase`][lowercase]
- [`DoubleEndedIterator for ToUppercase`][uppercase]
- [`TryFrom<&mut [T]> for [T; N]`][tryfrom_ref_arr]
- [`UnwindSafe for Once`][unwindsafe_once]
- [`RefUnwindSafe for Once`][refunwindsafe_once]
- [armv8 neon intrinsics for aarch64][stdarch/1266]

Const-stable:

- [`mem::MaybeUninit::as_ptr`][muninit_ptr]
- [`mem::MaybeUninit::assume_init`][muninit_init]
- [`mem::MaybeUninit::assume_init_ref`][muninit_init_ref]
- [`ffi::CStr::from_bytes_with_nul_unchecked`][cstr_from_bytes]

Cargo
-----

- [Stabilize the `strip` profile option][cargo/10088]
- [Stabilize future-incompat-report][cargo/10165]
- [Support abbreviating `--release` as `-r`][cargo/10133]
- [Support `term.quiet` configuration][cargo/10152]
- [Remove `--host` from cargo {publish,search,login}][cargo/10145]

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

- [Refactor weak symbols in std::sys::unix][90846]
  This may add new, versioned, symbols when building with a newer glibc, as the
  standard library uses weak linkage rather than dynamically attempting to load
  certain symbols at runtime.
- [Deprecate crate_type and crate_name nested inside `#![cfg_attr]`][83744]
  This adds a future compatibility lint to supporting the use of cfg_attr
  wrapping either crate_type or crate_name specification within Rust files;
  it is recommended that users migrate to setting the equivalent command line
  flags.
- [Remove effect of `#[no_link]` attribute on name resolution][92034]
  This may expose new names, leading to conflicts with preexisting names in a
  given namespace and a compilation failure.
- [Cargo will document libraries before binaries.][cargo/10172]
- [Respect doc=false in dependencies, not just the root crate][cargo/10201]
- [Weaken guarantee around advancing underlying iterators in zip][83791]
- [Make split_inclusive() on an empty slice yield an empty output][89825]
- [Update std::env::temp_dir to use GetTempPath2 on Windows when
  available.][89999]
- [unreachable! was updated to match other formatting macro behavior
  on Rust 2021][92137]

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

These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.

- [Fix many cases of normalization-related ICEs][91255]
- [Replace dominators algorithm with simple Lengauer-Tarjan][85013]
- [Store liveness in interval sets for region inference][90637]

- [Remove `in_band_lifetimes` from the compiler and standard library,
  in preparation for removing this unstable feature.][91867]

[91867]: rust-lang/rust#91867
[83744]: rust-lang/rust#83744
[83791]: rust-lang/rust#83791
[85013]: rust-lang/rust#85013
[89825]: rust-lang/rust#89825
[89999]: rust-lang/rust#89999
[90128]: rust-lang/rust#90128
[90207]: rust-lang/rust#90207
[90521]: rust-lang/rust#90521
[90586]: rust-lang/rust#90586
[90637]: rust-lang/rust#90637
[90833]: rust-lang/rust#90833
[90846]: rust-lang/rust#90846
[91003]: rust-lang/rust#91003
[91172]: rust-lang/rust#91172
[91255]: rust-lang/rust#91255
[91284]: rust-lang/rust#91284
[91535]: rust-lang/rust#91535
[91593]: rust-lang/rust#91593
[91728]: rust-lang/rust#91728
[91878]: rust-lang/rust#91878
[91896]: rust-lang/rust#91896
[91926]: rust-lang/rust#91926
[91984]: rust-lang/rust#91984
[92020]: rust-lang/rust#92020
[92034]: rust-lang/rust#92034
[92483]: rust-lang/rust#92483
[cargo/10088]: rust-lang/cargo#10088
[cargo/10133]: rust-lang/cargo#10133
[cargo/10145]: rust-lang/cargo#10145
[cargo/10152]: rust-lang/cargo#10152
[cargo/10165]: rust-lang/cargo#10165
[cargo/10172]: rust-lang/cargo#10172
[cargo/10201]: rust-lang/cargo#10201
[cargo/10269]: rust-lang/cargo#10269

[cstr_from_bytes]: https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.from_bytes_with_nul_unchecked
[muninit_ptr]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_ptr
[muninit_init]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init
[muninit_init_ref]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
[unwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-UnwindSafe
[refunwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-RefUnwindSafe
[tryfrom_ref_arr]: https://doc.rust-lang.org/stable/std/convert/trait.TryFrom.html#impl-TryFrom%3C%26%27_%20mut%20%5BT%5D%3E
[lowercase]: https://doc.rust-lang.org/stable/std/char/struct.ToLowercase.html#impl-DoubleEndedIterator
[uppercase]: https://doc.rust-lang.org/stable/std/char/struct.ToUppercase.html#impl-DoubleEndedIterator
[try_from_char_err]: https://doc.rust-lang.org/stable/std/char/struct.TryFromCharError.html
[available_parallelism]: https://doc.rust-lang.org/stable/std/thread/fn.available_parallelism.html
[result-copied]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.copied
[result-cloned]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.cloned
[asm]: https://doc.rust-lang.org/stable/core/arch/macro.asm.html
[global_asm]: https://doc.rust-lang.org/stable/core/arch/macro.global_asm.html
[is_break]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_break
[is_continue]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_continue
[try_from_char_u8]: https://doc.rust-lang.org/stable/std/primitive.char.html#impl-TryFrom%3Cchar%3E
[zip]: https://doc.rust-lang.org/stable/std/iter/fn.zip.html
[is_power_of_two8]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU8.html#method.is_power_of_two
[is_power_of_two16]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU16.html#method.is_power_of_two
[is_power_of_two32]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU32.html#method.is_power_of_two
[is_power_of_two64]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU64.html#method.is_power_of_two
[is_power_of_two128]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU128.html#method.is_power_of_two
[stdarch/1266]: rust-lang/stdarch#1266
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Apr 15, 2022
Pkgsrc changes:
 * Bump available bootstraps to 1.58.1.
 * Adjust one patch (and checksum) so that it still applies.

Upstream changes:

Version 1.59.0 (2022-02-24)
==========================

Language
--------

- [Stabilize default arguments for const generics][90207]
- [Stabilize destructuring assignment][90521]
- [Relax private in public lint on generic bounds and where clauses
  of trait impls][90586]
- [Stabilize asm! and global_asm! for x86, x86_64, ARM, Aarch64,
  and RISC-V][91728]

Compiler
--------

- [Stabilize new symbol mangling format, leaving it opt-in
  (-Csymbol-mangling-version=v0)][90128]
- [Emit LLVM optimization remarks when enabled with `-Cremark`][90833]
- [Fix sparc64 ABI for aggregates with floating point members][91003]
- [Warn when a `#[test]`-like built-in attribute macro is present
  multiple times.][91172]
- [Add support for riscv64gc-unknown-freebsd][91284]
- [Stabilize `-Z emit-future-incompat` as `--json future-incompat`][91535]
- [Soft disable incremental compilation][94124]

This release disables incremental compilation, unless the user has explicitly
opted in via the newly added RUSTC_FORCE_INCREMENTAL=1 environment variable.
This is due to a known and relatively frequently occurring bug in incremental
compilation, which causes builds to issue internal compiler errors. This
particular bug is already fixed on nightly, but that fix has not yet rolled out
to stable and is deemed too risky for a direct stable backport.

As always, we encourage users to test with nightly and report bugs so that we
can track failures and fix issues earlier.

See [94124] for more details.

[94124]: rust-lang/rust#94124

Libraries
---------

- [Remove unnecessary bounds for some Hash{Map,Set} methods][91593]

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

- [`std::thread::available_parallelism`][available_parallelism]
- [`Result::copied`][result-copied]
- [`Result::cloned`][result-cloned]
- [`arch::asm!`][asm]
- [`arch::global_asm!`][global_asm]
- [`ops::ControlFlow::is_break`][is_break]
- [`ops::ControlFlow::is_continue`][is_continue]
- [`TryFrom<char> for u8`][try_from_char_u8]
- [`char::TryFromCharError`][try_from_char_err]
  implementing `Clone`, `Debug`, `Display`, `PartialEq`, `Copy`, `Eq`, `Error`
- [`iter::zip`][zip]
- [`NonZeroU8::is_power_of_two`][is_power_of_two8]
- [`NonZeroU16::is_power_of_two`][is_power_of_two16]
- [`NonZeroU32::is_power_of_two`][is_power_of_two32]
- [`NonZeroU64::is_power_of_two`][is_power_of_two64]
- [`NonZeroU128::is_power_of_two`][is_power_of_two128]
- [`DoubleEndedIterator for ToLowercase`][lowercase]
- [`DoubleEndedIterator for ToUppercase`][uppercase]
- [`TryFrom<&mut [T]> for [T; N]`][tryfrom_ref_arr]
- [`UnwindSafe for Once`][unwindsafe_once]
- [`RefUnwindSafe for Once`][refunwindsafe_once]
- [armv8 neon intrinsics for aarch64][stdarch/1266]

Const-stable:

- [`mem::MaybeUninit::as_ptr`][muninit_ptr]
- [`mem::MaybeUninit::assume_init`][muninit_init]
- [`mem::MaybeUninit::assume_init_ref`][muninit_init_ref]
- [`ffi::CStr::from_bytes_with_nul_unchecked`][cstr_from_bytes]

Cargo
-----

- [Stabilize the `strip` profile option][cargo/10088]
- [Stabilize future-incompat-report][cargo/10165]
- [Support abbreviating `--release` as `-r`][cargo/10133]
- [Support `term.quiet` configuration][cargo/10152]
- [Remove `--host` from cargo {publish,search,login}][cargo/10145]

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

- [Refactor weak symbols in std::sys::unix][90846]
  This may add new, versioned, symbols when building with a newer glibc, as the
  standard library uses weak linkage rather than dynamically attempting to load
  certain symbols at runtime.
- [Deprecate crate_type and crate_name nested inside `#![cfg_attr]`][83744]
  This adds a future compatibility lint to supporting the use of cfg_attr
  wrapping either crate_type or crate_name specification within Rust files;
  it is recommended that users migrate to setting the equivalent command line
  flags.
- [Remove effect of `#[no_link]` attribute on name resolution][92034]
  This may expose new names, leading to conflicts with preexisting names in a
  given namespace and a compilation failure.
- [Cargo will document libraries before binaries.][cargo/10172]
- [Respect doc=false in dependencies, not just the root crate][cargo/10201]
- [Weaken guarantee around advancing underlying iterators in zip][83791]
- [Make split_inclusive() on an empty slice yield an empty output][89825]
- [Update std::env::temp_dir to use GetTempPath2 on Windows when
  available.][89999]
- [unreachable! was updated to match other formatting macro behavior
  on Rust 2021][92137]

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

These changes provide no direct user facing benefits, but represent significant
improvements to the internals and overall performance of rustc
and related tools.

- [Fix many cases of normalization-related ICEs][91255]
- [Replace dominators algorithm with simple Lengauer-Tarjan][85013]
- [Store liveness in interval sets for region inference][90637]

- [Remove `in_band_lifetimes` from the compiler and standard library,
  in preparation for removing this unstable feature.][91867]

[91867]: rust-lang/rust#91867
[83744]: rust-lang/rust#83744
[83791]: rust-lang/rust#83791
[85013]: rust-lang/rust#85013
[89825]: rust-lang/rust#89825
[89999]: rust-lang/rust#89999
[90128]: rust-lang/rust#90128
[90207]: rust-lang/rust#90207
[90521]: rust-lang/rust#90521
[90586]: rust-lang/rust#90586
[90637]: rust-lang/rust#90637
[90833]: rust-lang/rust#90833
[90846]: rust-lang/rust#90846
[91003]: rust-lang/rust#91003
[91172]: rust-lang/rust#91172
[91255]: rust-lang/rust#91255
[91284]: rust-lang/rust#91284
[91535]: rust-lang/rust#91535
[91593]: rust-lang/rust#91593
[91728]: rust-lang/rust#91728
[91878]: rust-lang/rust#91878
[91896]: rust-lang/rust#91896
[91926]: rust-lang/rust#91926
[91984]: rust-lang/rust#91984
[92020]: rust-lang/rust#92020
[92034]: rust-lang/rust#92034
[92483]: rust-lang/rust#92483
[cargo/10088]: rust-lang/cargo#10088
[cargo/10133]: rust-lang/cargo#10133
[cargo/10145]: rust-lang/cargo#10145
[cargo/10152]: rust-lang/cargo#10152
[cargo/10165]: rust-lang/cargo#10165
[cargo/10172]: rust-lang/cargo#10172
[cargo/10201]: rust-lang/cargo#10201
[cargo/10269]: rust-lang/cargo#10269

[cstr_from_bytes]: https://doc.rust-lang.org/stable/std/ffi/struct.CStr.html#method.from_bytes_with_nul_unchecked
[muninit_ptr]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.as_ptr
[muninit_init]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init
[muninit_init_ref]: https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#method.assume_init_ref
[unwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-UnwindSafe
[refunwindsafe_once]: https://doc.rust-lang.org/stable/std/sync/struct.Once.html#impl-RefUnwindSafe
[tryfrom_ref_arr]: https://doc.rust-lang.org/stable/std/convert/trait.TryFrom.html#impl-TryFrom%3C%26%27_%20mut%20%5BT%5D%3E
[lowercase]: https://doc.rust-lang.org/stable/std/char/struct.ToLowercase.html#impl-DoubleEndedIterator
[uppercase]: https://doc.rust-lang.org/stable/std/char/struct.ToUppercase.html#impl-DoubleEndedIterator
[try_from_char_err]: https://doc.rust-lang.org/stable/std/char/struct.TryFromCharError.html
[available_parallelism]: https://doc.rust-lang.org/stable/std/thread/fn.available_parallelism.html
[result-copied]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.copied
[result-cloned]: https://doc.rust-lang.org/stable/std/result/enum.Result.html#method.cloned
[asm]: https://doc.rust-lang.org/stable/core/arch/macro.asm.html
[global_asm]: https://doc.rust-lang.org/stable/core/arch/macro.global_asm.html
[is_break]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_break
[is_continue]: https://doc.rust-lang.org/stable/std/ops/enum.ControlFlow.html#method.is_continue
[try_from_char_u8]: https://doc.rust-lang.org/stable/std/primitive.char.html#impl-TryFrom%3Cchar%3E
[zip]: https://doc.rust-lang.org/stable/std/iter/fn.zip.html
[is_power_of_two8]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU8.html#method.is_power_of_two
[is_power_of_two16]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU16.html#method.is_power_of_two
[is_power_of_two32]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU32.html#method.is_power_of_two
[is_power_of_two64]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU64.html#method.is_power_of_two
[is_power_of_two128]: https://doc.rust-lang.org/stable/core/num/struct.NonZeroU128.html#method.is_power_of_two
[stdarch/1266]: rust-lang/stdarch#1266
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