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Stabilize uniform_paths #56759

Merged
merged 6 commits into from
Jan 12, 2019
Merged

Stabilize uniform_paths #56759

merged 6 commits into from
Jan 12, 2019

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petrochenkov
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@petrochenkov petrochenkov commented Dec 12, 2018

Address all the things described in #56417.

Assign visibilities to macro_rules items - pub to macro_export-ed macros and pub(crate) to non-exported macros, these visibilities determine how far these macros can be reexported with use.

Prohibit use of reexported inert attributes and "tool modules", after renaming (e.g. use inline as imported_inline) their respective tools and even compiler passes won't be able to recognize and properly check them.

Also turn use of uniform paths in 2015 macros into an error, I'd prefer to neither remove nor stabilize them right away because I still want to make some experiments in this area (uniform path fallback was added to 2015 macros used on 2018 edition in #56053 (comment)).

UPDATE: The last commit also stabilizes the feature uniform_paths.

Closes #53130
Closes #55618
Closes #56326
Closes #56398
Closes #56417
Closes #56821
Closes #57252
Closes #57422

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r? @Centril

@petrochenkov petrochenkov added T-lang Relevant to the language team, which will review and decide on the PR/issue. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 16, 2018
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bors commented Dec 18, 2018

☔ The latest upstream changes (presumably #56303) made this pull request unmergeable. Please resolve the merge conflicts.

@petrochenkov petrochenkov changed the title resolve: Prepare uniform paths to stabilization Stabilize uniform_paths Dec 27, 2018
@petrochenkov petrochenkov added beta-nominated Nominated for backporting to the compiler in the beta channel. S-waiting-on-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Dec 27, 2018
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@Centril
I've added one more commit actually stabilizing the feature.
Could you start an FCP?

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petrochenkov commented Dec 27, 2018

Stabilization report

Feature name: #![feature(uniform_paths)]
Version target: 1.32 (2019-01-18)

Implemented in #52923 (v1) and #55884 (v2) and landed 4.5 and 1.5 months ago respectively.
Tracking issues are #53130, #55618 and #56417.
Documentation issue is rust-lang/reference#487.
Tests for the feature can be found in src/test/run-pass/uniform-paths and src/test/ui/rust-2018/uniform-paths.

What is being stabilized

If import path resolves without errors, then it's resolved in exactly same way as a non-import path.

Possible extra errors (e.g. ambiguities) in import paths compared to other paths are caused by the fact that import paths are resolved early, when module structure of the crate is still in flux.
Some of the errors are artificial and can be relaxed backward-compatibly in the future, making import paths even closer to non-import paths.

Right now an ambiguity error is reported if the number of different candidates in scope for the first import segment (foo in use foo::bar::baz;) is more than one.
Multiple candidates with same definition don't produce an error:

struct S; // Candidate 1
fn main() {
    use self::S; // Candidate 2
    {
        use self::S; // Candidate 3
        use S as _; // Not an error
    }
}

Known issues

Known deviations of macro paths and 2018 import paths from the "uniform path" model

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Centril commented Dec 27, 2018

@petrochenkov

@Centril
I've added one more commit actually stabilizing the feature.
Could you start an FCP?

I've been meaning to read this and the other issues / descriptions you wrote but I've been a bit pressed for time. Would you mind waiting a bit (~a day) before I start FCP?

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@Centril
Sure, a day is okay, we have 3 weeks until the release.

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Tests, and from what I can see implementation, looks good.

Reassigning for further technical review to:
r? @nikomatsakis

@Centril Centril assigned nikomatsakis and unassigned Centril Dec 28, 2018
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Centril commented Dec 28, 2018

~A day later...

  • Proposal: treat #[macro_export] macro_rules! { ... } as pub, treat other macro_rules! { ... } as pub(crate).
  • Proposal: Allow imports of built-in attributes, but prohibit actually using names imported this way in attribute positions.
  • Proposal: Allow imports of derive helper attributes, but prohibit actually using names imported this way in attribute positions.
  • Proposal: Allow imports of tool modules, but prohibit actually using names imported this way in attribute paths.
  • Some of the errors are artificial and can be relaxed backward-compatibly in the future, making import paths even closer to non-import paths.

This seems like the right incremental balance for the time being. 👍

All in all, let's:

@rfcbot merge


Known deviations of macro paths and 2018 import paths from the "uniform path" model

There's still some future-proofing in place turning imports referring to local variables and generic parameters into errors - 22a13ef, but that future proofing has two holes.

These 2 holes seem quite pathological... but how much work work would it be to fix them?

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rfcbot commented Dec 28, 2018

Team member @Centril has proposed to merge this. The next step is review by the rest of the tagged teams:

No concerns currently listed.

Once a majority of reviewers approve (and none object), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

@rfcbot rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Dec 28, 2018
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petrochenkov commented Dec 28, 2018

These 2 holes seem quite pathological... but how much work work would it be to fix them?

The first one is relatively hard, but it only affects macros, not imports.
I'll look at the second one in the next few days, it shouldn't be too hard to fix, I just treated it as low-priority. UPDATE: Done in aa31d43

@Centril Centril added the relnotes Marks issues that should be documented in the release notes of the next release. label Dec 28, 2018
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I have a question: From the comments, it seemed like there was some "concern" about stabilizing this in time for the next release, is there any particular reason for that urgency?

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(Not saying I'm opposed, just asking)

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@bors r=nikomatsakis

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bors commented Jan 12, 2019

📌 Commit 250935d has been approved by nikomatsakis

@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-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). labels Jan 12, 2019
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@bors p=1
(Needs to get into the upcoming beta.)

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bors commented Jan 12, 2019

⌛ Testing commit 250935d with merge 1bcbb2c...

bors added a commit that referenced this pull request Jan 12, 2019
Stabilize `uniform_paths`

Address all the things described in #56417.

Assign visibilities to `macro_rules` items - `pub` to `macro_export`-ed macros and `pub(crate)` to non-exported macros, these visibilities determine how far these macros can be reexported with `use`.

Prohibit use of reexported inert attributes and "tool modules", after renaming (e.g. `use inline as imported_inline`) their respective tools and even compiler passes won't be able to recognize and properly check them.

Also turn use of uniform paths in 2015 macros into an error, I'd prefer to neither remove nor stabilize them right away because I still want to make some experiments in this area (uniform path fallback was added to 2015 macros used on 2018 edition in #56053 (comment)).

UPDATE: The last commit also stabilizes the feature `uniform_paths`.

Closes #53130
Closes #55618
Closes #56326
Closes #56398
Closes #56417
Closes #56821
Closes #57252
Closes #57422
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bors commented Jan 12, 2019

💔 Test failed - checks-travis

@bors bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jan 12, 2019
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The job dist-x86_64-apple of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.
[02:50:18] travis_time:end:stage2-cargo-miri:start=1547312941492659000,finish=1547312942099053000,duration=606394000

[02:50:18] [TIMING] ToolBuild { compiler: Compiler { stage: 2, host: "x86_64-apple-darwin" }, target: "x86_64-apple-darwin", tool: "cargo-miri", path: "src/tools/miri", mode: ToolRustc, is_optional_tool: true, source_type: Submodule, extra_features: [] } -- 0.637
[02:50:19] [TIMING] Miri { stage: 2, target: "x86_64-apple-darwin" } -- 1.472
The job exceeded the maximum time limit for jobs, and has been terminated.

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

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The job exceeded the maximum time limit for jobs, and has been terminated.

Looks spurious.
@bors retry

@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 Jan 12, 2019
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bors commented Jan 12, 2019

⌛ Testing commit 250935d with merge 75a369c...

bors added a commit that referenced this pull request Jan 12, 2019
Stabilize `uniform_paths`

Address all the things described in #56417.

Assign visibilities to `macro_rules` items - `pub` to `macro_export`-ed macros and `pub(crate)` to non-exported macros, these visibilities determine how far these macros can be reexported with `use`.

Prohibit use of reexported inert attributes and "tool modules", after renaming (e.g. `use inline as imported_inline`) their respective tools and even compiler passes won't be able to recognize and properly check them.

Also turn use of uniform paths in 2015 macros into an error, I'd prefer to neither remove nor stabilize them right away because I still want to make some experiments in this area (uniform path fallback was added to 2015 macros used on 2018 edition in #56053 (comment)).

UPDATE: The last commit also stabilizes the feature `uniform_paths`.

Closes #53130
Closes #55618
Closes #56326
Closes #56398
Closes #56417
Closes #56821
Closes #57252
Closes #57422
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bors commented Jan 12, 2019

☀️ Test successful - checks-travis, status-appveyor
Approved by: nikomatsakis
Pushing 75a369c to master...

@bors bors merged commit 250935d into rust-lang:master Jan 12, 2019
@rfcbot rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Jan 13, 2019
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request Jan 19, 2019
Changelog:
Version 1.32.0 (2019-01-17)
==========================

Language
--------
#### 2018 edition
- [You can now use the `?` operator in macro definitions.][56245] The `?`
  operator allows you to specify zero or one repetitions similar to the `*` and
  `+` operators.
- [Module paths with no leading keyword like `super`, `self`, or `crate`, will
  now always resolve to the item (`enum`, `struct`, etc.) available in the
  module if present, before resolving to a external crate or an item the prelude.][56759]
  E.g.
  ```rust
  enum Color { Red, Green, Blue }

  use Color::*;
  ```

#### All editions
- [You can now match against `PhantomData<T>` types.][55837]
- [You can now match against literals in macros with the `literal`
  specifier.][56072] This will match against a literal of any type.
  E.g. `1`, `'A'`, `"Hello World"`
- [Self can now be used as a constructor and pattern for unit and tuple structs.][56365] E.g.
  ```rust
  struct Point(i32, i32);

  impl Point {
      pub fn new(x: i32, y: i32) -> Self {
          Self(x, y)
      }

      pub fn is_origin(&self) -> bool {
          match self {
              Self(0, 0) => true,
              _ => false,
          }
      }
  }
  ```
- [Self can also now be used in type definitions.][56366] E.g.
  ```rust
  enum List<T>
  where
      Self: PartialOrd<Self> // can write `Self` instead of `List<T>`
  {
      Nil,
      Cons(T, Box<Self>) // likewise here
  }
  ```
- [You can now mark traits with `#[must_use]`.][55663] This provides a warning if
  a `impl Trait` or `dyn Trait` is returned and unused in the program.

Compiler
--------
- [The default allocator has changed from jemalloc to the default allocator on
  your system.][55238] The compiler itself on Linux & macOS will still use
  jemalloc, but programs compiled with it will use the system allocator.
- [Added the `aarch64-pc-windows-msvc` target.][55702]

Libraries
---------
- [`PathBuf` now implements `FromStr`.][55148]
- [`Box<[T]>` now implements `FromIterator<T>`.][55843]
- [The `dbg!` macro has been stabilized.][56395] This macro enables you to
  easily debug expressions in your rust program. E.g.
  ```rust
  let a = 2;
  let b = dbg!(a * 2) + 1;
  //      ^-- prints: [src/main.rs:4] a * 2 = 4
  assert_eq!(b, 5);
  ```

The following APIs are now `const` functions and can be used in a
`const` context.

- [`Cell::as_ptr`]
- [`UnsafeCell::get`]
- [`char::is_ascii`]
- [`iter::empty`]
- [`ManuallyDrop::new`]
- [`ManuallyDrop::into_inner`]
- [`RangeInclusive::start`]
- [`RangeInclusive::end`]
- [`NonNull::as_ptr`]
- [`slice::as_ptr`]
- [`str::as_ptr`]
- [`Duration::as_secs`]
- [`Duration::subsec_millis`]
- [`Duration::subsec_micros`]
- [`Duration::subsec_nanos`]
- [`CStr::as_ptr`]
- [`Ipv4Addr::is_unspecified`]
- [`Ipv6Addr::new`]
- [`Ipv6Addr::octets`]

Stabilized APIs
---------------
- [`i8::to_be_bytes`]
- [`i8::to_le_bytes`]
- [`i8::to_ne_bytes`]
- [`i8::from_be_bytes`]
- [`i8::from_le_bytes`]
- [`i8::from_ne_bytes`]
- [`i16::to_be_bytes`]
- [`i16::to_le_bytes`]
- [`i16::to_ne_bytes`]
- [`i16::from_be_bytes`]
- [`i16::from_le_bytes`]
- [`i16::from_ne_bytes`]
- [`i32::to_be_bytes`]
- [`i32::to_le_bytes`]
- [`i32::to_ne_bytes`]
- [`i32::from_be_bytes`]
- [`i32::from_le_bytes`]
- [`i32::from_ne_bytes`]
- [`i64::to_be_bytes`]
- [`i64::to_le_bytes`]
- [`i64::to_ne_bytes`]
- [`i64::from_be_bytes`]
- [`i64::from_le_bytes`]
- [`i64::from_ne_bytes`]
- [`i128::to_be_bytes`]
- [`i128::to_le_bytes`]
- [`i128::to_ne_bytes`]
- [`i128::from_be_bytes`]
- [`i128::from_le_bytes`]
- [`i128::from_ne_bytes`]
- [`isize::to_be_bytes`]
- [`isize::to_le_bytes`]
- [`isize::to_ne_bytes`]
- [`isize::from_be_bytes`]
- [`isize::from_le_bytes`]
- [`isize::from_ne_bytes`]
- [`u8::to_be_bytes`]
- [`u8::to_le_bytes`]
- [`u8::to_ne_bytes`]
- [`u8::from_be_bytes`]
- [`u8::from_le_bytes`]
- [`u8::from_ne_bytes`]
- [`u16::to_be_bytes`]
- [`u16::to_le_bytes`]
- [`u16::to_ne_bytes`]
- [`u16::from_be_bytes`]
- [`u16::from_le_bytes`]
- [`u16::from_ne_bytes`]
- [`u32::to_be_bytes`]
- [`u32::to_le_bytes`]
- [`u32::to_ne_bytes`]
- [`u32::from_be_bytes`]
- [`u32::from_le_bytes`]
- [`u32::from_ne_bytes`]
- [`u64::to_be_bytes`]
- [`u64::to_le_bytes`]
- [`u64::to_ne_bytes`]
- [`u64::from_be_bytes`]
- [`u64::from_le_bytes`]
- [`u64::from_ne_bytes`]
- [`u128::to_be_bytes`]
- [`u128::to_le_bytes`]
- [`u128::to_ne_bytes`]
- [`u128::from_be_bytes`]
- [`u128::from_le_bytes`]
- [`u128::from_ne_bytes`]
- [`usize::to_be_bytes`]
- [`usize::to_le_bytes`]
- [`usize::to_ne_bytes`]
- [`usize::from_be_bytes`]
- [`usize::from_le_bytes`]
- [`usize::from_ne_bytes`]

Cargo
-----
- [You can now run `cargo c` as an alias for `cargo check`.][cargo/6218]
- [Usernames are now allowed in alt registry URLs.][cargo/6242]

Misc
----
- [`libproc_macro` has been added to the `rust-src` distribution.][55280]

Compatibility Notes
-------------------
- [The argument types for AVX's
  `_mm256_stream_si256`, `_mm256_stream_pd`, `_mm256_stream_ps`][55610] have
  been changed from `*const` to `*mut` as the previous implementation
  was unsound.


[55148]: rust-lang/rust#55148
[55238]: rust-lang/rust#55238
[55280]: rust-lang/rust#55280
[55610]: rust-lang/rust#55610
[55663]: rust-lang/rust#55663
[55702]: https://github.com/rust-lag/rust/pull/55702/
[55837]: rust-lang/rust#55837
[55843]: rust-lang/rust#55843
[56072]: rust-lang/rust#56072
[56245]: rust-lang/rust#56245
[56365]: https:/ttps://github.com/rust-lang/rust/pull/56395/
[56759]: rust-lang/rust#56759
[cargo/6218]: rust-lang/cargo#6218
[cargo/6242]: rust-lang/cargo#6242
[`CStr::as_ptr`]: https://doc.rust-`Duration::as_secs`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs
[`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
[`Duration::subsec_millis`]: https://doc.rust-lang.org/sct.Duration.html#method.subsec_nanos
[`Ipv4Addr::is_unspecified`]: https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.is_unspecified
[`Ipv6Addr::new`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.new
[`Ipv6Addr::octets`]: httpw`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.new
[`NonNull::as_ptr`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.as_ptr
[`RangeInclusive::end`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.end
[`RangeInclusive::start`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.start
[`UnsafeCell::get`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get
[`slice::as_ptr`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr
[`char::is_ascii`]: https://doc.rust-lang.org/std/primitive.char.html#method.is_ascii
[`i128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_be_bytes
[`i128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_le_bytes
[`i128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_ne_bytes
[`i128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_be_bytes
[`i128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_le_bytes
[`i128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_ne_bytes
[`i16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_be_bytes
[`i16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_le_bytes
[`i16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_ne_bytes
[`i16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_be_bytes
[`i16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_le_bytes
[`i16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_ne_bytes
[`i32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_be_bytes
[`i32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_le_bytes
[`i32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_ne_bytes
[`i32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_be_bytes
[`i32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_le_bytes
[`i32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_ne_bytes
[`i64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_be_bytes
[`i64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_le_bytes
[`i64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_ne_bytes
[`i64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_be_bytes
[`i64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_le_bytes
[`i64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_ne_bytes
[`i8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_be_bytes
[`i8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_le_bytes
[`i8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_ne_bytes
[`i8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_be_bytes
[`i8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_le_bytes
[`i8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_ne_bytes
[`isize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_be_bytes
[`isize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_le_bytes
[`isize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_ne_bytes
[`isize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_be_bytes
[`isize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_le_bytes
[`isize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_ne_bytes
[`iter::empty`]: https://doc.rust-lang.org/std/iter/fn.empty.html
[`str::as_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_ptr
[`u128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_be_bytes
[`u128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_le_bytes
[`u128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_ne_bytes
[`u128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_be_bytes
[`u128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_le_bytes
[`u128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_ne_bytes
[`u16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_be_bytes
[`u16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_le_bytes
[`u16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_ne_bytes
[`u16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_be_bytes
[`u16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_le_bytes
[`u16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_ne_bytes
[`u32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_be_bytes
[`u32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_le_bytes
[`u32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_ne_bytes
[`u32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_be_bytes
[`u32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_le_bytes
[`u32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_ne_bytes
[`u64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_be_bytes
[`u64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_le_bytes
[`u64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_ne_bytes
[`u64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_be_bytes
[`u64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_le_bytes
[`u64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_ne_bytes
[`u8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_be_bytes
[`u8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_le_bytes
[`u8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_ne_bytes
[`u8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_be_bytes
[`u8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_le_bytes
[`u8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ne_bytes
[`usize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_be_bytes
[`usize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_le_bytes
[`usize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_ne_bytes
[`usize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_be_bytes
[`usize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_le_bytes
[`usize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_ne_bytes
@Centril Centril added this to the 1.32 milestone Apr 26, 2019
@petrochenkov petrochenkov deleted the prestabuni branch June 5, 2019 16:28
jperkin pushed a commit to TritonDataCenter/pkgsrc that referenced this pull request Jun 20, 2019
Changelog:
Version 1.32.0 (2019-01-17)
==========================

Language
--------
#### 2018 edition
- [You can now use the `?` operator in macro definitions.][56245] The `?`
  operator allows you to specify zero or one repetitions similar to the `*` and
  `+` operators.
- [Module paths with no leading keyword like `super`, `self`, or `crate`, will
  now always resolve to the item (`enum`, `struct`, etc.) available in the
  module if present, before resolving to a external crate or an item the prelude.][56759]
  E.g.
  ```rust
  enum Color { Red, Green, Blue }

  use Color::*;
  ```

#### All editions
- [You can now match against `PhantomData<T>` types.][55837]
- [You can now match against literals in macros with the `literal`
  specifier.][56072] This will match against a literal of any type.
  E.g. `1`, `'A'`, `"Hello World"`
- [Self can now be used as a constructor and pattern for unit and tuple structs.][56365] E.g.
  ```rust
  struct Point(i32, i32);

  impl Point {
      pub fn new(x: i32, y: i32) -> Self {
          Self(x, y)
      }

      pub fn is_origin(&self) -> bool {
          match self {
              Self(0, 0) => true,
              _ => false,
          }
      }
  }
  ```
- [Self can also now be used in type definitions.][56366] E.g.
  ```rust
  enum List<T>
  where
      Self: PartialOrd<Self> // can write `Self` instead of `List<T>`
  {
      Nil,
      Cons(T, Box<Self>) // likewise here
  }
  ```
- [You can now mark traits with `#[must_use]`.][55663] This provides a warning if
  a `impl Trait` or `dyn Trait` is returned and unused in the program.

Compiler
--------
- [The default allocator has changed from jemalloc to the default allocator on
  your system.][55238] The compiler itself on Linux & macOS will still use
  jemalloc, but programs compiled with it will use the system allocator.
- [Added the `aarch64-pc-windows-msvc` target.][55702]

Libraries
---------
- [`PathBuf` now implements `FromStr`.][55148]
- [`Box<[T]>` now implements `FromIterator<T>`.][55843]
- [The `dbg!` macro has been stabilized.][56395] This macro enables you to
  easily debug expressions in your rust program. E.g.
  ```rust
  let a = 2;
  let b = dbg!(a * 2) + 1;
  //      ^-- prints: [src/main.rs:4] a * 2 = 4
  assert_eq!(b, 5);
  ```

The following APIs are now `const` functions and can be used in a
`const` context.

- [`Cell::as_ptr`]
- [`UnsafeCell::get`]
- [`char::is_ascii`]
- [`iter::empty`]
- [`ManuallyDrop::new`]
- [`ManuallyDrop::into_inner`]
- [`RangeInclusive::start`]
- [`RangeInclusive::end`]
- [`NonNull::as_ptr`]
- [`slice::as_ptr`]
- [`str::as_ptr`]
- [`Duration::as_secs`]
- [`Duration::subsec_millis`]
- [`Duration::subsec_micros`]
- [`Duration::subsec_nanos`]
- [`CStr::as_ptr`]
- [`Ipv4Addr::is_unspecified`]
- [`Ipv6Addr::new`]
- [`Ipv6Addr::octets`]

Stabilized APIs
---------------
- [`i8::to_be_bytes`]
- [`i8::to_le_bytes`]
- [`i8::to_ne_bytes`]
- [`i8::from_be_bytes`]
- [`i8::from_le_bytes`]
- [`i8::from_ne_bytes`]
- [`i16::to_be_bytes`]
- [`i16::to_le_bytes`]
- [`i16::to_ne_bytes`]
- [`i16::from_be_bytes`]
- [`i16::from_le_bytes`]
- [`i16::from_ne_bytes`]
- [`i32::to_be_bytes`]
- [`i32::to_le_bytes`]
- [`i32::to_ne_bytes`]
- [`i32::from_be_bytes`]
- [`i32::from_le_bytes`]
- [`i32::from_ne_bytes`]
- [`i64::to_be_bytes`]
- [`i64::to_le_bytes`]
- [`i64::to_ne_bytes`]
- [`i64::from_be_bytes`]
- [`i64::from_le_bytes`]
- [`i64::from_ne_bytes`]
- [`i128::to_be_bytes`]
- [`i128::to_le_bytes`]
- [`i128::to_ne_bytes`]
- [`i128::from_be_bytes`]
- [`i128::from_le_bytes`]
- [`i128::from_ne_bytes`]
- [`isize::to_be_bytes`]
- [`isize::to_le_bytes`]
- [`isize::to_ne_bytes`]
- [`isize::from_be_bytes`]
- [`isize::from_le_bytes`]
- [`isize::from_ne_bytes`]
- [`u8::to_be_bytes`]
- [`u8::to_le_bytes`]
- [`u8::to_ne_bytes`]
- [`u8::from_be_bytes`]
- [`u8::from_le_bytes`]
- [`u8::from_ne_bytes`]
- [`u16::to_be_bytes`]
- [`u16::to_le_bytes`]
- [`u16::to_ne_bytes`]
- [`u16::from_be_bytes`]
- [`u16::from_le_bytes`]
- [`u16::from_ne_bytes`]
- [`u32::to_be_bytes`]
- [`u32::to_le_bytes`]
- [`u32::to_ne_bytes`]
- [`u32::from_be_bytes`]
- [`u32::from_le_bytes`]
- [`u32::from_ne_bytes`]
- [`u64::to_be_bytes`]
- [`u64::to_le_bytes`]
- [`u64::to_ne_bytes`]
- [`u64::from_be_bytes`]
- [`u64::from_le_bytes`]
- [`u64::from_ne_bytes`]
- [`u128::to_be_bytes`]
- [`u128::to_le_bytes`]
- [`u128::to_ne_bytes`]
- [`u128::from_be_bytes`]
- [`u128::from_le_bytes`]
- [`u128::from_ne_bytes`]
- [`usize::to_be_bytes`]
- [`usize::to_le_bytes`]
- [`usize::to_ne_bytes`]
- [`usize::from_be_bytes`]
- [`usize::from_le_bytes`]
- [`usize::from_ne_bytes`]

Cargo
-----
- [You can now run `cargo c` as an alias for `cargo check`.][cargo/6218]
- [Usernames are now allowed in alt registry URLs.][cargo/6242]

Misc
----
- [`libproc_macro` has been added to the `rust-src` distribution.][55280]

Compatibility Notes
-------------------
- [The argument types for AVX's
  `_mm256_stream_si256`, `_mm256_stream_pd`, `_mm256_stream_ps`][55610] have
  been changed from `*const` to `*mut` as the previous implementation
  was unsound.


[55148]: rust-lang/rust#55148
[55238]: rust-lang/rust#55238
[55280]: rust-lang/rust#55280
[55610]: rust-lang/rust#55610
[55663]: rust-lang/rust#55663
[55702]: https://github.com/rust-lag/rust/pull/55702/
[55837]: rust-lang/rust#55837
[55843]: rust-lang/rust#55843
[56072]: rust-lang/rust#56072
[56245]: rust-lang/rust#56245
[56365]: https:/ttps://github.com/rust-lang/rust/pull/56395/
[56759]: rust-lang/rust#56759
[cargo/6218]: rust-lang/cargo#6218
[cargo/6242]: rust-lang/cargo#6242
[`CStr::as_ptr`]: https://doc.rust-`Duration::as_secs`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.as_secs
[`Duration::subsec_micros`]: https://doc.rust-lang.org/std/time/struct.Duration.html#method.subsec_micros
[`Duration::subsec_millis`]: https://doc.rust-lang.org/sct.Duration.html#method.subsec_nanos
[`Ipv4Addr::is_unspecified`]: https://doc.rust-lang.org/std/net/struct.Ipv4Addr.html#method.is_unspecified
[`Ipv6Addr::new`]: https://doc.rust-lang.org/std/net/struct.Ipv6Addr.html#method.new
[`Ipv6Addr::octets`]: httpw`]: https://doc.rust-lang.org/std/mem/struct.ManuallyDrop.html#method.new
[`NonNull::as_ptr`]: https://doc.rust-lang.org/std/ptr/struct.NonNull.html#method.as_ptr
[`RangeInclusive::end`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.end
[`RangeInclusive::start`]: https://doc.rust-lang.org/std/ops/struct.RangeInclusive.html#method.start
[`UnsafeCell::get`]: https://doc.rust-lang.org/std/cell/struct.UnsafeCell.html#method.get
[`slice::as_ptr`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr
[`char::is_ascii`]: https://doc.rust-lang.org/std/primitive.char.html#method.is_ascii
[`i128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_be_bytes
[`i128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_le_bytes
[`i128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.from_ne_bytes
[`i128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_be_bytes
[`i128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_le_bytes
[`i128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i128.html#method.to_ne_bytes
[`i16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_be_bytes
[`i16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_le_bytes
[`i16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.from_ne_bytes
[`i16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_be_bytes
[`i16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_le_bytes
[`i16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i16.html#method.to_ne_bytes
[`i32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_be_bytes
[`i32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_le_bytes
[`i32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.from_ne_bytes
[`i32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_be_bytes
[`i32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_le_bytes
[`i32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i32.html#method.to_ne_bytes
[`i64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_be_bytes
[`i64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_le_bytes
[`i64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.from_ne_bytes
[`i64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_be_bytes
[`i64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_le_bytes
[`i64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i64.html#method.to_ne_bytes
[`i8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_be_bytes
[`i8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_le_bytes
[`i8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.from_ne_bytes
[`i8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_be_bytes
[`i8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_le_bytes
[`i8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.i8.html#method.to_ne_bytes
[`isize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_be_bytes
[`isize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_le_bytes
[`isize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.from_ne_bytes
[`isize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_be_bytes
[`isize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_le_bytes
[`isize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.isize.html#method.to_ne_bytes
[`iter::empty`]: https://doc.rust-lang.org/std/iter/fn.empty.html
[`str::as_ptr`]: https://doc.rust-lang.org/std/primitive.str.html#method.as_ptr
[`u128::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_be_bytes
[`u128::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_le_bytes
[`u128::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.from_ne_bytes
[`u128::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_be_bytes
[`u128::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_le_bytes
[`u128::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u128.html#method.to_ne_bytes
[`u16::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_be_bytes
[`u16::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_le_bytes
[`u16::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.from_ne_bytes
[`u16::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_be_bytes
[`u16::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_le_bytes
[`u16::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u16.html#method.to_ne_bytes
[`u32::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_be_bytes
[`u32::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_le_bytes
[`u32::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.from_ne_bytes
[`u32::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_be_bytes
[`u32::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_le_bytes
[`u32::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u32.html#method.to_ne_bytes
[`u64::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_be_bytes
[`u64::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_le_bytes
[`u64::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.from_ne_bytes
[`u64::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_be_bytes
[`u64::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_le_bytes
[`u64::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u64.html#method.to_ne_bytes
[`u8::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_be_bytes
[`u8::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_le_bytes
[`u8::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.from_ne_bytes
[`u8::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_be_bytes
[`u8::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_le_bytes
[`u8::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.u8.html#method.to_ne_bytes
[`usize::from_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_be_bytes
[`usize::from_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_le_bytes
[`usize::from_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.from_ne_bytes
[`usize::to_be_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_be_bytes
[`usize::to_le_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_le_bytes
[`usize::to_ne_bytes`]: https://doc.rust-lang.org/stable/std/primitive.usize.html#method.to_ne_bytes
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