Relax some Hash bounds on HashMap<K, V, S> and HashSet<T, S> #58370
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r? @Amanieu |
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Could you give a full example of when this would be useful? In particular, to construct a |
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The job Click to expand the log.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 |
Short answer: I shouldn't have to add Long answer: I do fancy things in this project of mine, in which I pointer cast Also, all other collections (apart from |
That is dealt with by #44491.
Ah; thanks. Btw.. |
I don't think you can call that "dealt with", given that means adding bounds to that collection when, say, |
Yeah, that's fair. |
Amanieu
reviewed
Feb 11, 2019
src/libstd/collections/hash/map.rs
Outdated
| /// let hasher: &RandomState = map.hasher(); | ||
| /// ``` | ||
| #[stable(feature = "hashmap_public_hasher", since = "1.9.0")] | ||
| pub fn hasher(&self) -> &S { |
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I would prefer if this function kept the S: BuildHasher bound. I have some changes to hashbrown (which will soon replace the libstd hashmap) which may require this bound in the future.
Do you really need to call map.hasher() without a S: BuildHasher bound? If you really need it then I can try looking into a workaround, but it might get a bit ugly.
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Do you really need to call
map.hasher()without aS: BuildHasherbound? If you really need it then I can try looking into a workaround, but it might get a bit ugly.
Nope, it was just one of the methods I saw that didn't need a bound, I can add it back.
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I moved it back where it was before with the same bounds.
|
Apart from my concern on |
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The job Click to expand the log.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 |
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Assuming the change for @rfcbot fcp merge |
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Awesome! I just wanted this the other day 🙂 (Same kind of things as nox already mentioned: passed a |
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Pushed a commit that I didn't intend to push directly in that PR, but I guess maybe I should? I did a similar patch for |
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Sorry, I meant |
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☔ The latest upstream changes (presumably #58341) made this pull request unmergeable. Please resolve the merge conflicts. |
Notably, hash iterators don't require any trait bounds to be iterated.
|
@rfcbot reviewed under the understanding that the set of API changes is: impl<K, V, S> HashMap<K, V, S>
- where
- K: Eq + Hash,
- S: BuildHasher,
{
fn capacity(&self) -> usize;
fn keys(&self) -> Keys<K, V>;
fn values(&self) -> Values<K, V>;
fn values_mut(&mut self) -> ValuesMut<K, V>;
fn iter(&self) -> Iter<K, V>;
fn iter_mut(&mut self) -> IterMut<K, V>;
fn len(&self) -> usize;
fn is_empty(&self) -> bool;
fn drain(&mut self) -> Drain<K, V>;
fn clear(&mut self);
}
impl<'a, K, V, S> IntoIterator for &'a HashMap<K, V, S>
- where
- K: Eq + Hash,
- S: BuildHasher;
impl<'a, K, V, S> IntoIterator for &'a mut HashMap<K, V, S>
- where
- K: Eq + Hash,
- S: BuildHasher;
impl<K, V, S> IntoIterator for HashMap<K, V, S>
- where
- K: Eq + Hash,
- S: BuildHasher;
impl<T, S> HashSet<T, S>
- where
- T: Eq + Hash,
- S: BuildHasher,
{
fn capacity(&self) -> usize;
fn iter(&self) -> Iter<T>;
fn len(&self) -> usize;
fn is_empty(&self) -> bool;
fn drain(&mut self) -> Drain<T>;
fn clear(&mut self);
}
impl<'a, T, S> IntoIterator for &'a HashSet<T, S>
- where
- T: Eq + Hash,
- S: BuildHasher;
impl<T, S> IntoIterator for HashSet<T, S>
- where
- T: Eq + Hash,
- S: BuildHasher; |
|
Edit: never mind, this isn't like Vec::drain where there can be items left afterward. |
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Currently |
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🔔 This is now entering its final comment period, as per the review above. 🔔 |
rfcbot
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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 @sfacklerfor their work and everyone else who contributed. The RFC will be merged soon. |
rfcbot
added
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@bors r+ |
|
📌 Commit d9e2259 has been approved by |
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Centril
added a commit
to Centril/rust
that referenced
this pull request
Feb 25, 2019
Relax some Hash bounds on HashMap<K, V, S> and HashSet<T, S> Notably, hash iterators don't require any trait bounds to be iterated.
bors
added a commit
that referenced
this pull request
Feb 25, 2019
Rollup of 5 pull requests Successful merges: - #58370 (Relax some Hash bounds on HashMap<K, V, S> and HashSet<T, S>) - #58421 (Relax some Ord bounds on BinaryHeap<T>) - #58686 (replace deprecated rustfmt_skip with rustfmt::skip) - #58697 (Use ? in some macros) - #58704 (Remove some unnecessary 'extern crate') Failed merges: r? @ghost
netbsd-srcmastr
pushed a commit
to NetBSD/pkgsrc
that referenced
this pull request
Apr 14, 2019
Pkgsrc changes:
* Bump required rust version to build to 1.33.0.
* Adapt patches to changed file locations.
* (I worry about 32-bit ports, now that Atomic64 apparently is First-Class;
this has been built on NetBSD/amd64 so far)
Upstream changes:
Version 1.34.0 (2019-04-11)
==========================
Language
--------
- [You can now use `#[deprecated = "reason"]`][58166] as a shorthand for
`#[deprecated(note = "reason")]`. This was previously allowed by mistake
but had no effect.
- [You can now accept token streams in `#[attr()]`,`#[attr[]]`, and
`#[attr{}]` procedural macros.][57367]
- [You can now write `extern crate self as foo;`][57407] to import your
crate's root into the extern prelude.
Compiler
--------
- [You can now target `riscv64imac-unknown-none-elf` and
`riscv64gc-unknown-none-elf`.][58406]
- [You can now enable linker plugin LTO optimisations with
`-C linker-plugin-lto`.][58057] This allows rustc to compile your Rust code
into LLVM bitcode allowing LLVM to perform LTO optimisations across C/C++ FFI
boundaries.
- [You can now target `powerpc64-unknown-freebsd`.][57809]
Libraries
---------
- [The trait bounds have been removed on some of `HashMap<K, V, S>`'s and
`HashSet<T, S>`'s basic methods.][58370] Most notably you no longer require
the `Hash` trait to create an iterator.
- [The `Ord` trait bounds have been removed on some of `BinaryHeap<T>`'s basic
methods.][58421] Most notably you no longer require the `Ord` trait to create
an iterator.
- [The methods `overflowing_neg` and `wrapping_neg` are now `const` functions
for all numeric types.][58044]
- [Indexing a `str` is now generic over all types that
implement `SliceIndex<str>`.][57604]
- [`str::trim`, `str::trim_matches`, `str::trim_{start, end}`, and
`str::trim_{start, end}_matches` are now `#[must_use]`][57106] and will
produce a warning if their returning type is unused.
- [The methods `checked_pow`, `saturating_pow`, `wrapping_pow`, and
`overflowing_pow` are now available for all numeric types.][57873] These are
equivalvent to methods such as `wrapping_add` for the `pow` operation.
Stabilized APIs
---------------
#### std & core
* [`Any::type_id`]
* [`Error::type_id`]
* [`atomic::AtomicI16`]
* [`atomic::AtomicI32`]
* [`atomic::AtomicI64`]
* [`atomic::AtomicI8`]
* [`atomic::AtomicU16`]
* [`atomic::AtomicU32`]
* [`atomic::AtomicU64`]
* [`atomic::AtomicU8`]
* [`convert::Infallible`]
* [`convert::TryFrom`]
* [`convert::TryInto`]
* [`iter::from_fn`]
* [`iter::successors`]
* [`num::NonZeroI128`]
* [`num::NonZeroI16`]
* [`num::NonZeroI32`]
* [`num::NonZeroI64`]
* [`num::NonZeroI8`]
* [`num::NonZeroIsize`]
* [`slice::sort_by_cached_key`]
* [`str::escape_debug`]
* [`str::escape_default`]
* [`str::escape_unicode`]
* [`str::split_ascii_whitespace`]
#### std
* [`Instant::checked_add`]
* [`Instant::checked_sub`]
* [`SystemTime::checked_add`]
* [`SystemTime::checked_sub`]
Cargo
-----
- [You can now use alternative registries to crates.io.][cargo/6654]
Misc
----
- [You can now use the `?` operator in your documentation tests without manually
adding `fn main() -> Result<(), _> {}`.][56470]
Compatibility Notes
-------------------
- [`Command::before_exec` is now deprecated in favor of the
unsafe method `Command::pre_exec`.][58059]
- [Use of `ATOMIC_{BOOL, ISIZE, USIZE}_INIT` is now deprecated.][57425] As you
can now use `const` functions in `static` variables.
[58370]: rust-lang/rust#58370
[58406]: rust-lang/rust#58406
[58421]: rust-lang/rust#58421
[58166]: rust-lang/rust#58166
[58044]: rust-lang/rust#58044
[58057]: rust-lang/rust#58057
[58059]: rust-lang/rust#58059
[57809]: rust-lang/rust#57809
[57873]: rust-lang/rust#57873
[57604]: rust-lang/rust#57604
[57367]: rust-lang/rust#57367
[57407]: rust-lang/rust#57407
[57425]: rust-lang/rust#57425
[57106]: rust-lang/rust#57106
[56470]: rust-lang/rust#56470
[cargo/6654]: rust-lang/cargo#6654
[`Any::type_id`]: https://doc.rust-lang.org/std/any/trait.Any.html#tymethod.type_id
[`Error::type_id`]: https://doc.rust-lang.org/std/error/trait.Error.html#tymethod.type_id
[`atomic::AtomicI16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI16.html
[`atomic::AtomicI32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI32.html
[`atomic::AtomicI64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI64.html
[`atomic::AtomicI8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI8.html
[`atomic::AtomicU16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU16.html
[`atomic::AtomicU32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU32.html
[`atomic::AtomicU64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU64.html
[`atomic::AtomicU8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU8.html
[`convert::Infallible`]: https://doc.rust-lang.org/std/convert/enum.Infallible.html
[`convert::TryFrom`]: https://doc.rust-lang.org/std/convert/trait.TryFrom.html
[`convert::TryInto`]: https://doc.rust-lang.org/std/convert/trait.TryInto.html
[`iter::from_fn`]: https://doc.rust-lang.org/std/iter/fn.from_fn.html
[`iter::successors`]: https://doc.rust-lang.org/std/iter/fn.successors.html
[`num::NonZeroI128`]: https://doc.rust-lang.org/std/num/struct.NonZeroI128.html
[`num::NonZeroI16`]: https://doc.rust-lang.org/std/num/struct.NonZeroI16.html
[`num::NonZeroI32`]: https://doc.rust-lang.org/std/num/struct.NonZeroI32.html
[`num::NonZeroI64`]: https://doc.rust-lang.org/std/num/struct.NonZeroI64.html
[`num::NonZeroI8`]: https://doc.rust-lang.org/std/num/struct.NonZeroI8.html
[`num::NonZeroIsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroIsize.html
[`slice::sort_by_cached_key`]: https://doc.rust-lang.org/std/slice/fn.sort_by_cached_key
[`str::escape_debug`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug
[`str::escape_default`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_default
[`str::escape_unicode`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_unicode
[`str::split_ascii_whitespace`]: https://doc.rust-lang.org/std/primitive.str.html#method.split_ascii_whitespace
[`Instant::checked_add`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_add
[`Instant::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_sub
[`SystemTime::checked_add`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_add
[`SystemTime::checked_sub`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_sub
netbsd-srcmastr
pushed a commit
to NetBSD/pkgsrc
that referenced
this pull request
May 19, 2019
Pkgsrc changes:
* Bump required rust version to build to 1.33.0.
* Adapt patches to changed file locations.
* (I worry about 32-bit ports, now that Atomic64 apparently is First-Class;
this has been built on NetBSD/amd64 so far)
Upstream changes:
Version 1.34.0 (2019-04-11)
==========================
Language
--------
- [You can now use `#[deprecated = "reason"]`][58166] as a shorthand for
`#[deprecated(note = "reason")]`. This was previously allowed by mistake
but had no effect.
- [You can now accept token streams in `#[attr()]`,`#[attr[]]`, and
`#[attr{}]` procedural macros.][57367]
- [You can now write `extern crate self as foo;`][57407] to import your
crate's root into the extern prelude.
Compiler
--------
- [You can now target `riscv64imac-unknown-none-elf` and
`riscv64gc-unknown-none-elf`.][58406]
- [You can now enable linker plugin LTO optimisations with
`-C linker-plugin-lto`.][58057] This allows rustc to compile your Rust code
into LLVM bitcode allowing LLVM to perform LTO optimisations across C/C++ FFI
boundaries.
- [You can now target `powerpc64-unknown-freebsd`.][57809]
Libraries
---------
- [The trait bounds have been removed on some of `HashMap<K, V, S>`'s and
`HashSet<T, S>`'s basic methods.][58370] Most notably you no longer require
the `Hash` trait to create an iterator.
- [The `Ord` trait bounds have been removed on some of `BinaryHeap<T>`'s basic
methods.][58421] Most notably you no longer require the `Ord` trait to create
an iterator.
- [The methods `overflowing_neg` and `wrapping_neg` are now `const` functions
for all numeric types.][58044]
- [Indexing a `str` is now generic over all types that
implement `SliceIndex<str>`.][57604]
- [`str::trim`, `str::trim_matches`, `str::trim_{start, end}`, and
`str::trim_{start, end}_matches` are now `#[must_use]`][57106] and will
produce a warning if their returning type is unused.
- [The methods `checked_pow`, `saturating_pow`, `wrapping_pow`, and
`overflowing_pow` are now available for all numeric types.][57873] These are
equivalvent to methods such as `wrapping_add` for the `pow` operation.
Stabilized APIs
---------------
#### std & core
* [`Any::type_id`]
* [`Error::type_id`]
* [`atomic::AtomicI16`]
* [`atomic::AtomicI32`]
* [`atomic::AtomicI64`]
* [`atomic::AtomicI8`]
* [`atomic::AtomicU16`]
* [`atomic::AtomicU32`]
* [`atomic::AtomicU64`]
* [`atomic::AtomicU8`]
* [`convert::Infallible`]
* [`convert::TryFrom`]
* [`convert::TryInto`]
* [`iter::from_fn`]
* [`iter::successors`]
* [`num::NonZeroI128`]
* [`num::NonZeroI16`]
* [`num::NonZeroI32`]
* [`num::NonZeroI64`]
* [`num::NonZeroI8`]
* [`num::NonZeroIsize`]
* [`slice::sort_by_cached_key`]
* [`str::escape_debug`]
* [`str::escape_default`]
* [`str::escape_unicode`]
* [`str::split_ascii_whitespace`]
#### std
* [`Instant::checked_add`]
* [`Instant::checked_sub`]
* [`SystemTime::checked_add`]
* [`SystemTime::checked_sub`]
Cargo
-----
- [You can now use alternative registries to crates.io.][cargo/6654]
Misc
----
- [You can now use the `?` operator in your documentation tests without manually
adding `fn main() -> Result<(), _> {}`.][56470]
Compatibility Notes
-------------------
- [`Command::before_exec` is now deprecated in favor of the
unsafe method `Command::pre_exec`.][58059]
- [Use of `ATOMIC_{BOOL, ISIZE, USIZE}_INIT` is now deprecated.][57425] As you
can now use `const` functions in `static` variables.
[58370]: rust-lang/rust#58370
[58406]: rust-lang/rust#58406
[58421]: rust-lang/rust#58421
[58166]: rust-lang/rust#58166
[58044]: rust-lang/rust#58044
[58057]: rust-lang/rust#58057
[58059]: rust-lang/rust#58059
[57809]: rust-lang/rust#57809
[57873]: rust-lang/rust#57873
[57604]: rust-lang/rust#57604
[57367]: rust-lang/rust#57367
[57407]: rust-lang/rust#57407
[57425]: rust-lang/rust#57425
[57106]: rust-lang/rust#57106
[56470]: rust-lang/rust#56470
[cargo/6654]: rust-lang/cargo#6654
[`Any::type_id`]: https://doc.rust-lang.org/std/any/trait.Any.html#tymethod.type_id
[`Error::type_id`]: https://doc.rust-lang.org/std/error/trait.Error.html#tymethod.type_id
[`atomic::AtomicI16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI16.html
[`atomic::AtomicI32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI32.html
[`atomic::AtomicI64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI64.html
[`atomic::AtomicI8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicI8.html
[`atomic::AtomicU16`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU16.html
[`atomic::AtomicU32`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU32.html
[`atomic::AtomicU64`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU64.html
[`atomic::AtomicU8`]: https://doc.rust-lang.org/std/atomic/struct.AtomicU8.html
[`convert::Infallible`]: https://doc.rust-lang.org/std/convert/enum.Infallible.html
[`convert::TryFrom`]: https://doc.rust-lang.org/std/convert/trait.TryFrom.html
[`convert::TryInto`]: https://doc.rust-lang.org/std/convert/trait.TryInto.html
[`iter::from_fn`]: https://doc.rust-lang.org/std/iter/fn.from_fn.html
[`iter::successors`]: https://doc.rust-lang.org/std/iter/fn.successors.html
[`num::NonZeroI128`]: https://doc.rust-lang.org/std/num/struct.NonZeroI128.html
[`num::NonZeroI16`]: https://doc.rust-lang.org/std/num/struct.NonZeroI16.html
[`num::NonZeroI32`]: https://doc.rust-lang.org/std/num/struct.NonZeroI32.html
[`num::NonZeroI64`]: https://doc.rust-lang.org/std/num/struct.NonZeroI64.html
[`num::NonZeroI8`]: https://doc.rust-lang.org/std/num/struct.NonZeroI8.html
[`num::NonZeroIsize`]: https://doc.rust-lang.org/std/num/struct.NonZeroIsize.html
[`slice::sort_by_cached_key`]: https://doc.rust-lang.org/std/slice/fn.sort_by_cached_key
[`str::escape_debug`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_debug
[`str::escape_default`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_default
[`str::escape_unicode`]: https://doc.rust-lang.org/std/primitive.str.html#method.escape_unicode
[`str::split_ascii_whitespace`]: https://doc.rust-lang.org/std/primitive.str.html#method.split_ascii_whitespace
[`Instant::checked_add`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_add
[`Instant::checked_sub`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.checked_sub
[`SystemTime::checked_add`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_add
[`SystemTime::checked_sub`]: https://doc.rust-lang.org/std/time/struct.SystemTime.html#method.checked_sub
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Notably, hash iterators don't require any trait bounds to be iterated.