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Derive Clone + Eq for std::string::FromUtf8Error #68738

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merged 1 commit into from
Feb 9, 2020
Merged

Derive Clone + Eq for std::string::FromUtf8Error #68738

merged 1 commit into from
Feb 9, 2020

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kennytm
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@kennytm kennytm commented Feb 1, 2020

Implement Clone and Eq for std::string::FromUtf8Error.

Both the inner Vec<u8> and std::str::Utf8Error are also Clone + Eq, so I don't see why we shouldn't derive them on FromUtf8Error as well.

(impl are insta-stable, requiring FCP from T-libs.)

@kennytm kennytm added T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. needs-fcp This change is insta-stable, so needs a completed FCP to proceed. labels Feb 1, 2020
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r? @sfackler

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sfackler commented Feb 1, 2020

My only potential concern would be if we changed the implementation to track more information such that previously equal values became non-equal in the future. I think that would probably fall under expected breakage though?

@rfcbot fcp merge

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rfcbot commented Feb 1, 2020 •
edited by Amanieu
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Team member @sfackler has proposed to merge this. The next step is review by the rest of the tagged team members:

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), 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 Feb 1, 2020
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dtolnay commented Feb 1, 2020

These seem fine but could you explain the use case that requires Clone and Eq so that we have a record when considering future cases? The ones for Utf8Error are 5 years old (#19741) and in that time I don't know of anyone having asked for them on FromUtf8Error.

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kennytm commented Feb 2, 2020

@sfackler We could switch to manually-implemented PartialEq to keep the previous behavior, if the previous behavior does make more sense.

@dtolnay I wanted to encapsulate Result<String, FromUtf8Error> as a single "maybe-UTF-8-string" object, and also implement Clone on it (PartialEq can be manually implemented).

While this type is isomorphic to Result<String, (Vec<u8>, Utf8Error)> so we don't require FromUtf8Error: Clone, I see no reason we should not implement Clone + PartialEq + Eq on it.

@kennytm kennytm added 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 Feb 5, 2020
@rfcbot rfcbot added the final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. label Feb 9, 2020
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rfcbot commented Feb 9, 2020

🔔 This is now entering its final comment period, as per the review above. 🔔

@rfcbot rfcbot removed the proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. label Feb 9, 2020
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sfackler commented Feb 9, 2020

@bors r+

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bors commented Feb 9, 2020

📌 Commit 847d5b4 has been approved by sfackler

@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 Feb 9, 2020
@jonas-schievink jonas-schievink mentioned this pull request Feb 9, 2020
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bors added a commit that referenced this pull request Feb 9, 2020
@bors
Auto merge of #69004 - jonas-schievink:rollup-z2ymler, r=jonas-schievink
71c7e14 
Rollup of 5 pull requests

Successful merges:

 - #68738 (Derive Clone + Eq for std::string::FromUtf8Error)
 - #68742 (implement AsMut<str> for String)
 - #68881 (rustc_codegen_llvm: always set AlwaysPreserve on all debuginfo variables)
 - #68911 (Speed up the inherent impl overlap check)
 - #68913 (Pretty-print generic params and where clauses on associated types)

Failed merges:

r? @ghost
@bors bors merged commit 847d5b4 into rust-lang:master Feb 9, 2020
@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 Feb 19, 2020
netbsd-srcmastr pushed a commit to NetBSD/pkgsrc that referenced this pull request May 16, 2020
@he32
Update lang/rust to version 1.43.0.
28527ca 
Pkgsrc changes:
 * Bump rust bootstrap version to 1.42.0, except for Darwin/i686 where the
   bootstrap is not (yet?) available.

Upstream changes:

Version 1.43.0 (2020-04-23)
==========================

Language
--------
- [Fixed using binary operations with `&{number}` (e.g. `&1.0`) not having
  the type inferred correctly.][68129]
- [Attributes such as `#[cfg()]` can now be used on `if` expressions.][69201]

**Syntax only changes**
- [Allow `type Foo: Ord` syntactically.][69361]
- [Fuse associated and extern items up to defaultness.][69194]
- [Syntactically allow `self` in all `fn` contexts.][68764]
- [Merge `fn` syntax + cleanup item parsing.][68728]
- [`item` macro fragments can be interpolated into `trait`s, `impl`s,
  and `extern` blocks.][69366]
  For example, you may now write:
  ```rust
  macro_rules! mac_trait {
      ($i:item) => {
          trait T { $i }
      }
  }
  mac_trait! {
      fn foo() {}
  }
  ```
These are still rejected *semantically*, so you will likely receive an error but
these changes can be seen and parsed by macros and
conditional compilation.


Compiler
--------
- [You can now pass multiple lint flags to rustc to override the previous
  flags.][67885] For example; `rustc -D unused -A unused-variables` denies
  everything in the `unused` lint group except `unused-variables` which
  is explicitly allowed. However, passing `rustc -A unused-variables -D unused` denies
  everything in the `unused` lint group **including** `unused-variables` since
  the allow flag is specified before the deny flag (and therefore overridden).
- [rustc will now prefer your system MinGW libraries over its bundled libraries
  if they are available on `windows-gnu`.][67429]
- [rustc now buffers errors/warnings printed in JSON.][69227]

Libraries
---------
- [`Arc<[T; N]>`, `Box<[T; N]>`, and `Rc<[T; N]>`, now implement
  `TryFrom<Arc<[T]>>`,`TryFrom<Box<[T]>>`, and `TryFrom<Rc<[T]>>`
  respectively.][69538] **Note** These conversions are only available when `N`
  is `0..=32`.
- [You can now use associated constants on floats and integers directly, rather
  than having to import the module.][68952] e.g. You can now write `u32::MAX` or
  `f32::NAN` with no imports.
- [`u8::is_ascii` is now `const`.][68984]
- [`String` now implements `AsMut<str>`.][68742]
- [Added the `primitive` module to `std` and `core`.][67637] This module
  reexports Rust's primitive types. This is mainly useful in macros
  where you want avoid these types being shadowed.
- [Relaxed some of the trait bounds on `HashMap` and `HashSet`.][67642]
- [`string::FromUtf8Error` now implements `Clone + Eq`.][68738]

Stabilized APIs
---------------
- [`Once::is_completed`]
- [`f32::LOG10_2`]
- [`f32::LOG2_10`]
- [`f64::LOG10_2`]
- [`f64::LOG2_10`]
- [`iter::once_with`]

Cargo
-----
- [You can now set config `[profile]`s in your `.cargo/config`, or through
  your environment.][cargo/7823]
- [Cargo will now set `CARGO_BIN_EXE_<name>` pointing to a binary's
  executable path when running integration tests or benchmarks.][cargo/7697]
  `<name>` is the name of your binary as-is e.g. If you wanted the executable
  path for a binary named `my-program`you would use
  `env!("CARGO_BIN_EXE_my-program")`.

Misc
----
- [Certain checks in the `const_err` lint were deemed unrelated to const
  evaluation][69185], and have been moved to the `unconditional_panic` and
  `arithmetic_overflow` lints.

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

- [Having trailing syntax in the `assert!` macro is now a hard error.][69548]
  This has been a warning since 1.36.0.
- [Fixed `Self` not having the correctly inferred type.][69340] This incorrectly
  led to some instances being accepted, and now correctly emits a hard error.

[69340]: rust-lang/rust#69340

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

- [All components are now built with `opt-level=3` instead of `2`.][67878]
- [Improved how rustc generates drop code.][67332]
- [Improved performance from `#[inline]`-ing certain hot functions.][69256]
- [traits: preallocate 2 Vecs of known initial size][69022]
- [Avoid exponential behaviour when relating types][68772]
- [Skip `Drop` terminators for enum variants without drop glue][68943]
- [Improve performance of coherence checks][68966]
- [Deduplicate types in the generator witness][68672]
- [Invert control in struct_lint_level.][68725]

[67332]: rust-lang/rust#67332
[67429]: rust-lang/rust#67429
[67637]: rust-lang/rust#67637
[67642]: rust-lang/rust#67642
[67878]: rust-lang/rust#67878
[67885]: rust-lang/rust#67885
[68129]: rust-lang/rust#68129
[68672]: rust-lang/rust#68672
[68725]: rust-lang/rust#68725
[68728]: rust-lang/rust#68728
[68738]: rust-lang/rust#68738
[68742]: rust-lang/rust#68742
[68764]: rust-lang/rust#68764
[68772]: rust-lang/rust#68772
[68943]: rust-lang/rust#68943
[68952]: rust-lang/rust#68952
[68966]: rust-lang/rust#68966
[68984]: rust-lang/rust#68984
[69022]: rust-lang/rust#69022
[69185]: rust-lang/rust#69185
[69194]: rust-lang/rust#69194
[69201]: rust-lang/rust#69201
[69227]: rust-lang/rust#69227
[69548]: rust-lang/rust#69548
[69256]: rust-lang/rust#69256
[69361]: rust-lang/rust#69361
[69366]: rust-lang/rust#69366
[69538]: rust-lang/rust#69538
[cargo/7823]: rust-lang/cargo#7823
[cargo/7697]: rust-lang/cargo#7697
[`Once::is_completed`]: https://doc.rust-lang.org/std/sync/struct.Once.html#method.is_completed
[`f32::LOG10_2`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG10_2.html
[`f32::LOG2_10`]: https://doc.rust-lang.org/std/f32/consts/constant.LOG2_10.html
[`f64::LOG10_2`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG10_2.html
[`f64::LOG2_10`]: https://doc.rust-lang.org/std/f64/consts/constant.LOG2_10.html
[`iter::once_with`]: https://doc.rust-lang.org/std/iter/fn.once_with.html
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