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Add [T; N]: TryFrom<Vec<T>>
(insta-stable)
#76310
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(rust_highfive has picked a reviewer for you, use r? to override) |
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This is very similar to the existing `Box<[T; N]>: TryFrom<Box<[T]>>`, but allows avoiding the `shrink_to_fit` if you have a vector and not a boxed slice.
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Code looks good (apart from Rust version nit). Having Vec<T>
be the error type also makes sense to me.
As this is insta-stable and I can't start FCPs:
r? @KodrAus
Oh right, review comments are not picked up. r? @KodrAus |
Team member @KodrAus 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. |
Thanks, Amanieu Co-authored-by: Amanieu d'Antras <[email protected]>
🔔 This is now entering its final comment period, as per the review above. 🔔 |
The final comment period, with a disposition to merge, as per the review above, is now complete. As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed. The RFC will be merged soon. |
@bors r+ |
📌 Commit 3d89ee9 has been approved by |
It's unclear to me what happened here -- maybe the job just never started? https://buildbot2.rust-lang.org/homu/results/rust/76310 @bors retry |
⌛ Testing commit 3d89ee9 with merge f976b4641b963dbcc1ed4edb155fce5db28807b1... |
💔 Test failed - checks-actions |
Can't tell what failed. This is the only failing job I see: seemed to be working then got killed with signal 9. Finished release [optimized] target(s) in 1m 05s
[TIMING] ToolBuild { compiler: Compiler { stage: 0, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None }, tool: "tidy", path: "src/tools/tidy", mode: ToolBootstrap, is_optional_tool: false, source_type: InTree, extra_features: [] } -- 65.034
[TIMING] Tidy { compiler: Compiler { stage: 0, host: TargetSelection { triple: "x86_64-apple-darwin", file: None } }, target: TargetSelection { triple: "x86_64-apple-darwin", file: None } } -- 0.000
tidy check
command did not execute successfully: "/Users/runner/work/rust/rust/build/x86_64-apple-darwin/stage0-tools-bin/tidy" "/Users/runner/work/rust/rust" "/Users/runner/work/rust/rust/build/x86_64-apple-darwin/stage0/bin/cargo"
expected success, got: signal: 9
failed to run: /Users/runner/work/rust/rust/build/bootstrap/debug/bootstrap --stage 2 test
Build completed unsuccessfully in 0:01:13 @bors retry |
Add `[T; N]: TryFrom<Vec<T>>` (insta-stable) This is very similar to the [existing](https://doc.rust-lang.org/nightly/std/convert/trait.TryFrom.html#impl-TryFrom%3CBox%3C%5BT%5D%3E%3E) `Box<[T; N]>: TryFrom<Box<[T]>>`, but allows avoiding the `shrink_to_fit` if you have a vector and not a boxed slice. Like the slice equivalents of this, it fails if the length of the vector is not exactly `N`. This uses `Vec<T>` as the `Error` type to return the input, like how the `Rc<[T]> -> Rc<[T; N]>` (and Arc) ones also reflect the input directly in the error type. ```rust #[stable(feature = "array_try_from_vec", since = "1.47.0")] impl<T, const N: usize> TryFrom<Vec<T>> for [T; N] { type Error = Vec<T>; fn try_from(mut vec: Vec<T>) -> Result<[T; N], Vec<T>>; } ``` Inspired by this zulip thread: https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/APIs.20for.20getting.20stuff.20from.20a.20Vec.20by.20owned/near/209048103
@bors rollup |
Rollup of 14 pull requests Successful merges: - rust-lang#73963 (deny(unsafe_op_in_unsafe_fn) in libstd/path.rs) - rust-lang#75099 (lint/ty: move fns to avoid abstraction violation) - rust-lang#75502 (Use implicit (not explicit) rules for promotability by default in `const fn`) - rust-lang#75580 (Add test for checking duplicated branch or-patterns) - rust-lang#76310 (Add `[T; N]: TryFrom<Vec<T>>` (insta-stable)) - rust-lang#76400 (Clean up vec benches bench_in_place style) - rust-lang#76434 (do not inline black_box when building for Miri) - rust-lang#76492 (Add associated constant `BITS` to all integer types) - rust-lang#76525 (Add as_str() to string::Drain.) - rust-lang#76636 (assert ScalarMaybeUninit size) - rust-lang#76749 (give *even better* suggestion when matching a const range) - rust-lang#76757 (don't convert types to the same type with try_into (clippy::useless_conversion)) - rust-lang#76796 (Give a better error message when x.py uses the wrong stage for CI) - rust-lang#76798 (Build fixes for RISC-V 32-bit Linux support) Failed merges: r? `@ghost`
Clean up some of the pkgsrc Makefile, there's still lots in here that should just be deleted though. Switch SunOS to the illumos bootstrap by default. Version 1.48.0 (2020-11-19) ========================== Language -------- - [The `unsafe` keyword is now syntactically permitted on modules.][75857] This is still rejected *semantically*, but can now be parsed by procedural macros. Compiler -------- - [Stabilised the `-C link-self-contained=<yes|no>` compiler flag.][76158] This tells `rustc` whether to link its own C runtime and libraries or to rely on a external linker to find them. (Supported only on `windows-gnu`, `linux-musl`, and `wasi` platforms.) - [You can now use `-C target-feature=+crt-static` on `linux-gnu` targets.][77386] Note: If you're using cargo you must explicitly pass the `--target` flag. - [Added tier 2\* support for `aarch64-unknown-linux-musl`.][76420] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`io::Write` is now implemented for `&ChildStdin` `&Sink`, `&Stdout`, and `&Stderr`.][76275] - [All arrays of any length now implement `TryFrom<Vec<T>>`.][76310] - [The `matches!` macro now supports having a trailing comma.][74880] - [`Vec<A>` now implements `PartialEq<[B]>` where `A: PartialEq<B>`.][74194] - [The `RefCell::{replace, replace_with, clone}` methods now all use `#[track_caller]`.][77055] Stabilized APIs --------------- - [`slice::as_ptr_range`] - [`slice::as_mut_ptr_range`] - [`VecDeque::make_contiguous`] - [`future::pending`] - [`future::ready`] The following previously stable methods are now `const fn`'s: - [`Option::is_some`] - [`Option::is_none`] - [`Option::as_ref`] - [`Result::is_ok`] - [`Result::is_err`] - [`Result::as_ref`] - [`Ordering::reverse`] - [`Ordering::then`] Cargo ----- Rustdoc ------- - [You can now link to items in `rustdoc` using the intra-doc link syntax.][74430] E.g. ``/// Uses [`std::future`]`` will automatically generate a link to `std::future`'s documentation. See ["Linking to items by name"][intradoc-links] for more information. - [You can now specify `#[doc(alias = "<alias>")]` on items to add search aliases when searching through `rustdoc`'s UI.][75740] Compatibility Notes ------------------- - [Promotion of references to `'static` lifetime inside `const fn` now follows the same rules as inside a `fn` body.][75502] In particular, `&foo()` will not be promoted to `'static` lifetime any more inside `const fn`s. - [Associated type bindings on trait objects are now verified to meet the bounds declared on the trait when checking that they implement the trait.][27675] - [When trait bounds on associated types or opaque types are ambiguous, the compiler no longer makes an arbitrary choice on which bound to use.][54121] - [Fixed recursive nonterminals not being expanded in macros during pretty-print/reparse check.][77153] This may cause errors if your macro wasn't correctly handling recursive nonterminal tokens. - [`&mut` references to non zero-sized types are no longer promoted.][75585] - [`rustc` will now warn if you use attributes like `#[link_name]` or `#[cold]` in places where they have no effect.][73461] - [Updated `_mm256_extract_epi8` and `_mm256_extract_epi16` signatures in `arch::{x86, x86_64}` to return `i32` to match the vendor signatures.][73166] - [`mem::uninitialized` will now panic if any inner types inside a struct or enum disallow zero-initialization.][71274] - [`#[target_feature]` will now error if used in a place where it has no effect.][78143] - [Foreign exceptions are now caught by `catch_unwind` and will cause an abort.][70212] Note: This behaviour is not guaranteed and is still considered undefined behaviour, see the [`catch_unwind`] documentation for further information. 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. - [Building `rustc` from source now uses `ninja` by default over `make`.][74922] You can continue building with `make` by setting `ninja=false` in your `config.toml`. - [cg_llvm: `fewer_names` in `uncached_llvm_type`][76030] - [Made `ensure_sufficient_stack()` non-generic][76680] [78143]: rust-lang/rust#78143 [76680]: rust-lang/rust#76680 [76030]: rust-lang/rust#76030 [70212]: rust-lang/rust#70212 [27675]: rust-lang/rust#27675 [54121]: rust-lang/rust#54121 [71274]: rust-lang/rust#71274 [77386]: rust-lang/rust#77386 [77153]: rust-lang/rust#77153 [77055]: rust-lang/rust#77055 [76275]: rust-lang/rust#76275 [76310]: rust-lang/rust#76310 [76420]: rust-lang/rust#76420 [76158]: rust-lang/rust#76158 [75857]: rust-lang/rust#75857 [75585]: rust-lang/rust#75585 [75740]: rust-lang/rust#75740 [75502]: rust-lang/rust#75502 [74880]: rust-lang/rust#74880 [74922]: rust-lang/rust#74922 [74430]: rust-lang/rust#74430 [74194]: rust-lang/rust#74194 [73461]: rust-lang/rust#73461 [73166]: rust-lang/rust#73166 [intradoc-links]: https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html [`catch_unwind`]: https://doc.rust-lang.org/std/panic/fn.catch_unwind.html [`Option::is_some`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some [`Option::is_none`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none [`Option::as_ref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_ref [`Result::is_ok`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok [`Result::is_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err [`Result::as_ref`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.as_ref [`Ordering::reverse`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.reverse [`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then [`slice::as_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr_range [`slice::as_mut_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_mut_ptr_range [`VecDeque::make_contiguous`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.make_contiguous [`future::pending`]: https://doc.rust-lang.org/std/future/fn.pending.html [`future::ready`]: https://doc.rust-lang.org/std/future/fn.ready.html
Pkgsrc changes: * Compensate for files being moved around upstream. * Introduce optional, on-by-default semi-static building of cargo, using the internal curl and openssl sources. This reduces the dynamic dependencies of cargo and therefore the rust package itself. Ref. options.mk. * The 1.47.0 bootstrap kits have been re-built with the above option turned on, so no longer depends on curl or openssl from pkgsrc and/or from earlier OS or pkgsrc versions. This should hopefully fix installation of rust with non-default PREFIX, ref. PR#54453. Upstream changes: Version 1.48.0 (2020-11-19) ========================== Language -------- - [The `unsafe` keyword is now syntactically permitted on modules.][75857] This is still rejected *semantically*, but can now be parsed by procedural macros. Compiler -------- - [Stabilised the `-C link-self-contained=<yes|no>` compiler flag.][76158] This tells `rustc` whether to link its own C runtime and libraries or to rely on a external linker to find them. (Supported only on `windows-gnu`, `linux-musl`, and `wasi` platforms.) - [You can now use `-C target-feature=+crt-static` on `linux-gnu` targets.] [77386] Note: If you're using cargo you must explicitly pass the `--target` flag. - [Added tier 2\* support for `aarch64-unknown-linux-musl`.][76420] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [`io::Write` is now implemented for `&ChildStdin` `&Sink`, `&Stdout`, and `&Stderr`.][76275] - [All arrays of any length now implement `TryFrom<Vec<T>>`.][76310] - [The `matches!` macro now supports having a trailing comma.][74880] - [`Vec<A>` now implements `PartialEq<[B]>` where `A: PartialEq<B>`.][74194] - [The `RefCell::{replace, replace_with, clone}` methods now all use `#[track_caller]`.][77055] Stabilized APIs --------------- - [`slice::as_ptr_range`] - [`slice::as_mut_ptr_range`] - [`VecDeque::make_contiguous`] - [`future::pending`] - [`future::ready`] The following previously stable methods are now `const fn`'s: - [`Option::is_some`] - [`Option::is_none`] - [`Option::as_ref`] - [`Result::is_ok`] - [`Result::is_err`] - [`Result::as_ref`] - [`Ordering::reverse`] - [`Ordering::then`] Cargo ----- Rustdoc ------- - [You can now link to items in `rustdoc` using the intra-doc link syntax.][74430] E.g. ``/// Uses [`std::future`]`` will automatically generate a link to `std::future`'s documentation. See ["Linking to items by name"][intradoc-links] for more information. - [You can now specify `#[doc(alias = "<alias>")]` on items to add search aliases when searching through `rustdoc`'s UI.][75740] Compatibility Notes ------------------- - [Promotion of references to `'static` lifetime inside `const fn` now follows the same rules as inside a `fn` body.][75502] In particular, `&foo()` will not be promoted to `'static` lifetime any more inside `const fn`s. - [Associated type bindings on trait objects are now verified to meet the bounds declared on the trait when checking that they implement the trait.][27675] - [When trait bounds on associated types or opaque types are ambiguous, the compiler no longer makes an arbitrary choice on which bound to use.][54121] - [Fixed recursive nonterminals not being expanded in macros during pretty-print/reparse check.][77153] This may cause errors if your macro wasn't correctly handling recursive nonterminal tokens. - [`&mut` references to non zero-sized types are no longer promoted.][75585] - [`rustc` will now warn if you use attributes like `#[link_name]` or `#[cold]` in places where they have no effect.][73461] - [Updated `_mm256_extract_epi8` and `_mm256_extract_epi16` signatures in `arch::{x86, x86_64}` to return `i32` to match the vendor signatures.][73166] - [`mem::uninitialized` will now panic if any inner types inside a struct or enum disallow zero-initialization.][71274] - [`#[target_feature]` will now error if used in a place where it has no effect.][78143] - [Foreign exceptions are now caught by `catch_unwind` and will cause an abort.][70212] Note: This behaviour is not guaranteed and is still considered undefined behaviour, see the [`catch_unwind`] documentation for further information. 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. - [Building `rustc` from source now uses `ninja` by default over `make`.][74922] You can continue building with `make` by setting `ninja=false` in your `config.toml`. - [cg_llvm: `fewer_names` in `uncached_llvm_type`][76030] - [Made `ensure_sufficient_stack()` non-generic][76680] [78143]: rust-lang/rust#78143 [76680]: rust-lang/rust#76680 [76030]: rust-lang/rust#76030 [70212]: rust-lang/rust#70212 [27675]: rust-lang/rust#27675 [54121]: rust-lang/rust#54121 [71274]: rust-lang/rust#71274 [77386]: rust-lang/rust#77386 [77153]: rust-lang/rust#77153 [77055]: rust-lang/rust#77055 [76275]: rust-lang/rust#76275 [76310]: rust-lang/rust#76310 [76420]: rust-lang/rust#76420 [76158]: rust-lang/rust#76158 [75857]: rust-lang/rust#75857 [75585]: rust-lang/rust#75585 [75740]: rust-lang/rust#75740 [75502]: rust-lang/rust#75502 [74880]: rust-lang/rust#74880 [74922]: rust-lang/rust#74922 [74430]: rust-lang/rust#74430 [74194]: rust-lang/rust#74194 [73461]: rust-lang/rust#73461 [73166]: rust-lang/rust#73166 [intradoc-links]: https://doc.rust-lang.org/rustdoc/linking-to-items-by-name.html [`catch_unwind`]: https://doc.rust-lang.org/std/panic/fn.catch_unwind.html [`Option::is_some`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_some [`Option::is_none`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.is_none [`Option::as_ref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_ref [`Result::is_ok`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_ok [`Result::is_err`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.is_err [`Result::as_ref`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.as_ref [`Ordering::reverse`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.reverse [`Ordering::then`]: https://doc.rust-lang.org/std/cmp/enum.Ordering.html#method.then [`slice::as_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_ptr_range [`slice::as_mut_ptr_range`]: https://doc.rust-lang.org/std/primitive.slice.html#method.as_mut_ptr_range [`VecDeque::make_contiguous`]: https://doc.rust-lang.org/std/collections/struct.VecDeque.html#method.make_contiguous [`future::pending`]: https://doc.rust-lang.org/std/future/fn.pending.html [`future::ready`]: https://doc.rust-lang.org/std/future/fn.ready.html
Add `Box<[T; N]>: TryFrom<Vec<T>>` We have `[T; N]: TryFrom<Vec<T>>` (rust-lang#76310) and `Box<[T; N]>: TryFrom<Box<[T]>>`, but not this combination. `vec.into_boxed_slice().try_into()` isn't quite a replacement for this, as that'll reallocate unnecessarily in the error case. **Insta-stable, so needs an FCP** (I tried to make this work with `, A`, but that's disallowed because of `#[fundamental]` rust-lang#29635 (comment))
This is very similar to the existing
Box<[T; N]>: TryFrom<Box<[T]>>
, but allows avoiding theshrink_to_fit
if you have a vector and not a boxed slice.Like the slice equivalents of this, it fails if the length of the vector is not exactly
N
.This uses
Vec<T>
as theError
type to return the input, like how theRc<[T]> -> Rc<[T; N]>
(and Arc) ones also reflect the input directly in the error type.Inspired by this zulip thread: https://rust-lang.zulipchat.com/#narrow/stream/219381-t-libs/topic/APIs.20for.20getting.20stuff.20from.20a.20Vec.20by.20owned/near/209048103