Support cfg and cfg_attr on generic parameters#61547
Conversation
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r? @pnkfelix (rust_highfive has picked a reviewer for you, use r? to override) |
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I don't know whether we have any lint check attributes that affect generic parameters, but how does the language interact with those before / after this PR? |
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I see no reason not to do this and every reason to both in terms of consistency and usability. That said, since it is a language change, let's formally approve this change... @rfcbot merge |
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Team member @Centril 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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N.B. Aaron is on leave so I've checked their box. |
This change is orthogonal to lint checking attributes. fn f<#[allow(warnings)] foo>() {} // warning: type parameter `foo` should have an upper camel case name |
Thanks! Would you mind filing an issue if there isn't one already? |
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🔔 This is now entering its final comment period, as per the review above. 🔔 |
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r? @Centril r=me rollup on the implementation when FCP completes. |
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☔ The latest upstream changes (presumably #60669) made this pull request unmergeable. Please resolve the merge conflicts. |
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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 the author for their work and everyone else who contributed. The RFC will be merged soon. |
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@bors r=Centril rollup |
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📌 Commit 0b58bb3 has been approved by |
Support `cfg` and `cfg_attr` on generic parameters `cfg` attributes are supported in all other positions where attributes are accepted at all. They were previously prohibited in rust-lang#51283 because they weren't implemented correctly before that and were simply ignored.
Support `cfg` and `cfg_attr` on generic parameters `cfg` attributes are supported in all other positions where attributes are accepted at all. They were previously prohibited in rust-lang#51283 because they weren't implemented correctly before that and were simply ignored.
Pkgsrc changes:
* Add a patch to llvm to deal with const dli_saddr.
* Adapt two other patches.
* Cross-build currently fails, so i386, powerpc and sparc64 bootstrap
kits for 1.37.0 are built natively. Missing aarch64 hardware, so that's
not available yet.
* Bump bootstrap requirements to 1.36.0 except for armv7-unknown-netbsd-eabihf
which I've not managed to cross-build.
Upstream changes:
Version 1.37.0 (2019-08-15)
==========================
Language
--------
- `#[must_use]` will now warn if the type is contained in a [tuple][61100],
[`Box`][62228], or an [array][62235] and unused.
- [You can now use the `cfg` and `cfg_attr` attributes on
generic parameters.][61547]
- [You can now use enum variants through type alias.][61682] e.g. You can
write the following:
```rust
type MyOption = Option<u8>;
fn increment_or_zero(x: MyOption) -> u8 {
match x {
MyOption::Some(y) => y + 1,
MyOption::None => 0,
}
}
```
- [You can now use `_` as an identifier for consts.][61347] e.g. You can write
`const _: u32 = 5;`.
- [You can now use `#[repr(align(X)]` on enums.][61229]
- [The `?`/_"Kleene"_ macro operator is now available in the
2015 edition.][60932]
Compiler
--------
- [You can now enable Profile-Guided Optimization with the `-C profile-generate`
and `-C profile-use` flags.][61268] For more information on how to use profile
guided optimization, please refer to the [rustc book][rustc-book-pgo].
- [The `rust-lldb` wrapper script should now work again.][61827]
Libraries
---------
- [`mem::MaybeUninit<T>` is now ABI-compatible with `T`.][61802]
Stabilized APIs
---------------
- [`BufReader::buffer`]
- [`BufWriter::buffer`]
- [`Cell::from_mut`]
- [`Cell<[T]>::as_slice_of_cells`][`Cell<slice>::as_slice_of_cells`]
- [`DoubleEndedIterator::nth_back`]
- [`Option::xor`]
- [`Wrapping::reverse_bits`]
- [`i128::reverse_bits`]
- [`i16::reverse_bits`]
- [`i32::reverse_bits`]
- [`i64::reverse_bits`]
- [`i8::reverse_bits`]
- [`isize::reverse_bits`]
- [`slice::copy_within`]
- [`u128::reverse_bits`]
- [`u16::reverse_bits`]
- [`u32::reverse_bits`]
- [`u64::reverse_bits`]
- [`u8::reverse_bits`]
- [`usize::reverse_bits`]
Cargo
-----
- [`Cargo.lock` files are now included by default when publishing executable crates
with executables.][cargo/7026]
- [You can now specify `default-run="foo"` in `[package]` to specify the
default executable to use for `cargo run`.][cargo/7056]
Misc
----
Compatibility Notes
-------------------
- [Using `...` for inclusive range patterns will now warn by default.][61342]
Please transition your code to using the `..=` syntax for inclusive
ranges instead.
- [Using a trait object without the `dyn` will now warn by default.][61203]
Please transition your code to use `dyn Trait` for trait objects instead.
[62228]: rust-lang/rust#62228
[62235]: rust-lang/rust#62235
[61802]: rust-lang/rust#61802
[61827]: rust-lang/rust#61827
[61547]: rust-lang/rust#61547
[61682]: rust-lang/rust#61682
[61268]: rust-lang/rust#61268
[61342]: rust-lang/rust#61342
[61347]: rust-lang/rust#61347
[61100]: rust-lang/rust#61100
[61203]: rust-lang/rust#61203
[61229]: rust-lang/rust#61229
[60932]: rust-lang/rust#60932
[cargo/7026]: rust-lang/cargo#7026
[cargo/7056]: rust-lang/cargo#7056
[`BufReader::buffer`]: https://doc.rust-lang.org/std/io/struct.BufReader.html#method.buffer
[`BufWriter::buffer`]: https://doc.rust-lang.org/std/io/struct.BufWriter.html#method.buffer
[`Cell::from_mut`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.from_mut
[`Cell<slice>::as_slice_of_cells`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_slice_of_cells
[`DoubleEndedIterator::nth_back`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.nth_back
[`Option::xor`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.xor
[`RefCell::try_borrow_unguarded`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.try_borrow_unguarded
[`Wrapping::reverse_bits`]: https://doc.rust-lang.org/std/num/struct.Wrapping.html#method.reverse_bits
[`i128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i128.html#method.reverse_bits
[`i16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i16.html#method.reverse_bits
[`i32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i32.html#method.reverse_bits
[`i64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i64.html#method.reverse_bits
[`i8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i8.html#method.reverse_bits
[`isize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.isize.html#method.reverse_bits
[`slice::copy_within`]: https://doc.rust-lang.org/std/primitive.slice.html#method.copy_within
[`u128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u128.html#method.reverse_bits
[`u16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u16.html#method.reverse_bits
[`u32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u32.html#method.reverse_bits
[`u64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u64.html#method.reverse_bits
[`u8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u8.html#method.reverse_bits
[`usize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.usize.html#method.reverse_bits
[rustc-book-pgo]: https://doc.rust-lang.org/rustc/profile-guided-optimization.html
cfgattributes are supported in all other positions where attributes are accepted at all.They were previously prohibited in #51283 because they weren't implemented correctly before that and were simply ignored.