Extend the `#[must_use]` lint to arrays by varkor · Pull Request #62235 · rust-lang/rust

varkor · 2019-06-29T15:25:54Z

Based on top of #62228.

src/librustc_lint/unused.rs

Centril · 2019-06-29T15:50:03Z

r=me with CI passing, the first nit fixed, and optionally the second.

@rust-lang/lang N.B. This PR extends #[must_use] to arrays. I believe this should be uncontroversial given #61100 and our approval of that given that an array can be viewed as a sort of homogeneous tuple type. Arrays are also structural-ish.

varkor · 2019-06-29T19:43:27Z

@bors r=Centril

bors · 2019-06-29T19:43:28Z

📌 Commit 0fccbf0 has been approved by Centril

@Centril

…entril Extend the `#[must_use]` lint to arrays Based on top of rust-lang#62228. r? @Centril

Centril · 2019-06-30T12:26:12Z

@bors r- ; seems we have a toolstate failure in #62242 (comment).

varkor · 2019-06-30T14:32:48Z

This will be fixed once rust-lang/miri#806 is merged.

Centril · 2019-06-30T14:34:54Z

r=me then :)

varkor · 2019-06-30T16:45:28Z

@bors r=Centril

bors · 2019-06-30T16:45:29Z

📌 Commit 0fccbf0 has been approved by Centril

varkor · 2019-06-30T17:21:28Z

@bors r=Centril

bors · 2019-06-30T17:21:28Z

📌 Commit 76f5b50 has been approved by Centril

@Centril

…entril Extend the `#[must_use]` lint to arrays Based on top of rust-lang#62228. r? @Centril

@ghost

Rollup of 8 pull requests Successful merges: - #62062 (Use a more efficient iteration order for forward dataflow) - #62063 (Use a more efficient iteration order for backward dataflow) - #62224 (rustdoc: remove unused derives and variants) - #62228 (Extend the #[must_use] lint to boxed types) - #62235 (Extend the `#[must_use]` lint to arrays) - #62239 (Fix a typo) - #62241 (Always parse 'async unsafe fn' + properly ban in 2015) - #62248 (before_exec actually will only get deprecated with 1.37) Failed merges: r? @ghost

Extend `#[must_use]` to nested structures Extends the `#[must_use]` lint to apply when `#[must_use]` types are nested within `struct`s (or one-variant `enum`s), making the lint much more generally useful. This is in line with #61100 extending the lint to tuples. Fixes #39524. cc @rust-lang/lang and @rust-lang/compiler for discussion in case this is a controversial change. In particular, we might want to consider allowing annotations on fields containing `#[must_use]` types in user-defined types (e.g. `#[allow(unused_must_use)]`) to opt out of this behaviour, if there are cases where we this this is likely to have frequent false positives. (This is based on top of #62235.)

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

Extend `#[must_use]` to nested structures Extends the `#[must_use]` lint to apply when `#[must_use]` types are nested within `struct`s (or one-variant `enum`s), making the lint much more generally useful. This is in line with #61100 extending the lint to tuples. Fixes #39524. cc @rust-lang/lang and @rust-lang/compiler for discussion in case this is a controversial change. In particular, we might want to consider allowing annotations on fields containing `#[must_use]` types in user-defined types (e.g. `#[allow(unused_must_use)]`) to opt out of this behaviour, if there are cases where we this this is likely to have frequent false positives. (This is based on top of #62235.)

rust-highfive assigned Centril Jun 29, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jun 29, 2019

Centril reviewed Jun 29, 2019

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varkor force-pushed the must_use-adt-components branch from ffc5bf7 to 0fccbf0 Compare June 29, 2019 16:02

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-review Status: Awaiting review from the assignee but also interested parties. labels Jun 29, 2019

Centril added a commit to Centril/rust that referenced this pull request Jun 29, 2019

Rollup merge of rust-lang#62235 - varkor:must_use-adt-components, r=C…

eedbfc0

…entril Extend the `#[must_use]` lint to arrays Based on top of rust-lang#62228. r? @Centril

Centril mentioned this pull request Jun 29, 2019

Rollup of 5 pull requests #62242

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bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 30, 2019

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 30, 2019

varkor added 5 commits June 30, 2019 18:19

Extend the #[must_use] lint to boxed types

b613ef1

Improve error messages for boxed trait objects in tuples

d066f19

Fix run-pass tests

75f31e7

Update miri

400fd60

Extend #[must_use] lint to arrays

76f5b50

varkor force-pushed the must_use-adt-components branch from 0fccbf0 to 76f5b50 Compare June 30, 2019 17:21

Centril added a commit to Centril/rust that referenced this pull request Jun 30, 2019

Rollup merge of rust-lang#62235 - varkor:must_use-adt-components, r=C…

2b313b1

…entril Extend the `#[must_use]` lint to arrays Based on top of rust-lang#62228. r? @Centril

Centril mentioned this pull request Jun 30, 2019

Rollup of 8 pull requests #62253

Merged

This was referenced Jul 1, 2019

Extend #[must_use] to nested structures #62262

Closed

rust-highfive only warns about updated submodules when a PR is created rust-lang/highfive#223

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bors merged commit 76f5b50 into rust-lang:master Jul 1, 2019

Centril added relnotes Marks issues that should be documented in the release notes of the next release. T-lang Relevant to the language team labels Jul 1, 2019

Centril added this to the 1.37 milestone Jul 1, 2019

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Extend the `#[must_use]` lint to arrays#62235

Extend the `#[must_use]` lint to arrays#62235
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