Apply #[must_use] lint to components of tuples #61100

varkor · 2019-05-23T21:57:03Z

Fixes #61061.

rust-highfive · 2019-05-23T21:57:15Z

r? @michaelwoerister

(rust_highfive has picked a reviewer for you, use r? to override)

varkor · 2019-05-23T21:57:37Z

@bors try (for crater run)

bors · 2019-05-23T21:57:49Z

⌛ Trying commit 4a5e4efe85075bbb7347a09f77515d89f4df5514 with merge 49ae6b765de90f324a1eb52a6884406f2543815f...

src/test/ui/lint/must_use-tuple.rs

bors · 2019-05-23T23:26:34Z

💔 Test failed - checks-travis

varkor · 2019-05-24T00:32:08Z

@TimNN: the above error message cut off the important part.

varkor · 2019-05-24T00:37:54Z

@bors try

(I tested this before, but one of the compiler internal lints failed.)

bors · 2019-05-24T00:38:08Z

⌛ Trying commit 68c0ced with merge 58b2112...

Apply #[must_use] lint to components of tuples Fixes #61061.

bors · 2019-05-24T02:51:50Z

☀️ Try build successful - checks-travis
Build commit: 58b2112

varkor · 2019-05-24T08:24:42Z

@craterbot run mode=check-only

craterbot · 2019-05-24T08:24:45Z

👌 Experiment pr-61100 created and queued.
🤖 Automatically detected try build 58b2112
🔍 You can check out the queue and this experiment's details.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2019-05-24T08:24:47Z

🚧 Experiment pr-61100 is now running on agent aws-3-tmp.

ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

craterbot · 2019-05-26T00:08:26Z

🎉 Experiment pr-61100 is completed!
📊 2 regressed and 0 fixed (60951 total)
📰 Open the full report.

⚠️ If you notice any spurious failure please add them to the blacklist!
ℹ️ Crater is a tool to run experiments across parts of the Rust ecosystem. Learn more

Centril · 2019-05-27T04:53:41Z

That's a rather small amount of regressions... Possibly too few?
...This seems bad in terms of justifying adding the lint to (t0, .., tn)?

On the other hand, the supporting code is small... thoughts?

varkor · 2019-05-27T14:22:46Z

On the other hand, the supporting code is small... thoughts?

I think this change is small enough that there's not much reason to prefer not to add it if it helps catch a few more mistakes. There aren't going to be any additional false positives either.

varkor · 2019-05-27T15:49:22Z

A warning is produced for each #[must_use] component of a tuple now, pointing to the correct span.

r? @cramertj

cramertj · 2019-06-03T16:39:00Z

r=me with missing test. Thanks so much for doing this! :)

varkor · 2019-06-03T17:50:08Z

@bors r=cramertj

bors · 2019-06-03T17:50:11Z

📌 Commit de2bf3a has been approved by cramertj

bors · 2019-06-03T19:12:24Z

⌛ Testing commit de2bf3a with merge 6ffb8f5...

Apply #[must_use] lint to components of tuples Fixes #61061.

bors · 2019-06-03T22:05:49Z

☀️ Test successful - checks-travis, status-appveyor
Approved by: cramertj
Pushing 6ffb8f5 to master...

scottmcm · 2019-06-03T22:15:42Z

This seems bad in terms of justifying adding the lint

I don't think crater should necessarily be expected to find lint warnings, @Centril, because it's code that theoretically works. It can't tell use whether someone wrote the code wrong, had to debug to find it, fixed it, and then uploaded to crates.io once it worked.

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 michaelwoerister May 23, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 23, 2019

varkor mentioned this pull request May 23, 2019

tuples containing #[must_use] types should be #[must_use] #61061

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cramertj reviewed May 23, 2019

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varkor force-pushed the must_use-tuple-expr branch from 4a5e4ef to 68c0ced Compare May 24, 2019 00:36

bors added a commit that referenced this pull request May 24, 2019

Auto merge of #61100 - varkor:must_use-tuple-expr, r=<try>

58b2112

Apply #[must_use] lint to components of tuples Fixes #61061.

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels May 24, 2019

craterbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-crater Status: Waiting on a crater run to be completed. labels May 26, 2019

varkor added 6 commits June 3, 2019 18:19

Warn for #[must_use] in tuples

bbac81a

Add test for #[must_use] in tuples

fd36b5f

Use precise span for must_use tuple components

e121d96

Fix issue with recursively encountering uninhabited type

3c768ad

Add function call to test

058551c

Specify tuple element in lint message

81fa794

varkor force-pushed the must_use-tuple-expr branch from d65e7d2 to de2bf3a Compare June 3, 2019 17:50

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 3, 2019

Add nested must_use variant

de2bf3a

bors added a commit that referenced this pull request Jun 3, 2019

Auto merge of #61100 - varkor:must_use-tuple-expr, r=cramertj

6ffb8f5

Apply #[must_use] lint to components of tuples Fixes #61061.

bors added the merged-by-bors This PR was explicitly merged by bors. label Jun 3, 2019

bors merged commit de2bf3a into rust-lang:master Jun 3, 2019

varkor deleted the must_use-tuple-expr branch June 3, 2019 22:09

Centril mentioned this pull request Jun 29, 2019

Extend the #[must_use] lint to arrays #62235

Merged

varkor mentioned this pull request Jul 1, 2019

Extend #[must_use] to nested structures #62262

Closed

matthiaskrgr mentioned this pull request Mar 25, 2024

Using derive(PartialEq) on an enum with a variant that accepts(Box<dyn SomeTrait>) causes cryptic build error. #123056

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Apply #[must_use] lint to components of tuples #61100

Apply #[must_use] lint to components of tuples #61100

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Apply #[must_use] lint to components of tuples #61100

Apply #[must_use] lint to components of tuples #61100

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