Stabilize assoc_int_consts associated int/float constants #68952
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Great work, thanks!
(If you are comfortable with git rebase/squash/fixup you could improve the git history a bit by squashing your three "Fix ..." commits with the respective commits that is being fixed. That makes it a bit easier for commit-by-commit reviewing. However, that's really not important.)
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The code changes are good. However, as I mentioned in chat, I am not really a fan of stabilizing these constants only a few weeks after they have been added. @Mark-Simulacrum disagreed. To get another opinion and since I can't start FCP merges anyway, reassigning: r? @dtolnay |
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Git history fixed :) I usually do that, but must have been lazy this time. Thanks. With regards to when to stabilize. My two cents is that things sit around as unstable because we are evaluating if the naming is good, the API has a usable/ergonomic design, it's properly implemented, people actually seem to use/want this etc. But we basically already know all those things for this feature. It just moves an existing feature. For reference, moving the |
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Thanks, I think it's pretty clear that we want these so I am on board with moving forward.
I think the deprecation notice on the integer modules is too aggressive for now.
Could you remove the bold second sentences? I think this is not among the most important information to feature in the module index, especially not with emphasis. I think the links inside the module showing what to use instead are sufficient.
Could you also restore the "See also the i16 primitive type." links exactly how it existed before? Anyone who lands on the module's documentation is much more likely looking for the type and its methods, not the associated constants. So the way you've put the type link at the end of a paragraph about deprecation warnings and associated constants is not as good.
Sure. Add it to a new line so it ends up in the module docs, but not in the first-line summary like now? Or remove
Will do. |
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Done. |
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@rfcbot fcp merge @rust-lang/libs: This stabilizes associated constants on the primitive integer and float types to make e.g. i64::MAX work the way we've always liked for them to work, without importing std::i64. The constants involved are:
The existing module-level constants' documentation will now link to the associated constants, but we don't trigger any new deprecation warnings. We can navigate deprecation at some (far) later time. |
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Team member @dtolnay 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. |
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☔ The latest upstream changes (presumably #68491) made this pull request unmergeable. Please resolve the merge conflicts. |
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finally stop using min/max_value and the integer modules rust-lang/rust#68952 landed, so we can finally do this :)
Use associated constants of integer types Take advantage of rust-lang#68952 in the interpreter and some nearby modules :)
Use associated constants of integer types Take advantage of rust-lang#68952 in the interpreter and some nearby modules :)
Use associated constants of integer types Take advantage of rust-lang#68952 in the interpreter and some nearby modules :)
Use associated constants of integer types Take advantage of rust-lang#68952 in the interpreter and some nearby modules :)
Use associated constants of integer types Take advantage of rust-lang#68952 in the interpreter and some nearby modules :)
Use associated numeric consts in documentation Now when the associated constants on int/float types are stabilized and the recommended way of accessing said constants (rust-lang#68952). We can start using it in this repository, and recommend it via documentation example code. This PR is the reincarnation of rust-lang#67913 minus the actual adding + stabilization of said constants. (EDIT: Now it's only changing the documentation. So users will see the new consts, but we don't yet update the internal code) Because of how fast bit rot happens to PRs that touch this many files, it does not try to replace 100% of the old usage of the constants in the entire repo, but a good chunk of them.
Use associated numeric consts in documentation Now when the associated constants on int/float types are stabilized and the recommended way of accessing said constants (rust-lang#68952). We can start using it in this repository, and recommend it via documentation example code. This PR is the reincarnation of rust-lang#67913 minus the actual adding + stabilization of said constants. (EDIT: Now it's only changing the documentation. So users will see the new consts, but we don't yet update the internal code) Because of how fast bit rot happens to PRs that touch this many files, it does not try to replace 100% of the old usage of the constants in the entire repo, but a good chunk of them.
Use assoc int and float consts instead of module level ones changelog: Recommend primitive type associated constants instead of module level constants In Rust 1.43 integer and float primitive types will have a number of new associated constants. For example `MAX`, `MIN` and a number of constants related to the machine representation of floats. rust-lang/rust#68952 These new constants are preferred over the module level constants in `{core,std}::{f*, u*, i*}`. I have in the last few days made sure that the documentation in the main rust repository uses the new constants in every place I could find (rust-lang/rust#69860, rust-lang/rust#70782). So the next step is naturally to make the linter recommend the new constants as well. This PR only changes two lints. There are more. But I did not want the PR to be too big. And since I have not contributed to clippy before it felt saner to start with a small PR so I see if there are any quirks. More will come later.
…dtolnay Add const examples I only added them to `std::f32` to get feedback on this approach before adding the other constants. When looking at rust-lang#68952, I found the docs a little confusing. Unless you're intimately aware of what's going on here, I don't think it's super clear what is deprecated and what you're supposed to do instead. I think short examples really clarify what's meant here, so that's what I did.
…dtolnay Add const examples I only added them to `std::f32` to get feedback on this approach before adding the other constants. When looking at rust-lang#68952, I found the docs a little confusing. Unless you're intimately aware of what's going on here, I don't think it's super clear what is deprecated and what you're supposed to do instead. I think short examples really clarify what's meant here, so that's what I did.
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
The next step in RFC rust-lang/rfcs#2700 (tracking issue #68490). Stabilizing the associated constants that were added in #68325.
assoc_int_constsfeature flag.uint_macroand useint_macrofor all integer types since the macros were identical anyway.r? @LukasKalbertodt