syntax: Support modern attribute syntax in the `meta` matcher #63674

petrochenkov · 2019-08-17T23:17:57Z

Where "modern" means #57367:

PATH
PATH `(` TOKEN_STREAM `)`
PATH `[` TOKEN_STREAM `]`
PATH `{` TOKEN_STREAM `}`

Unfortunately, meta wasn't future-proofed using the FOLLOW token set like other matchers (#34011), so code like $meta:meta { or $meta:meta [ may break, and we need a crater run to find out how often this happens in practice.

Closes #49629 (by fully supporting meta rather than removing it.)

rust-highfive · 2019-08-17T23:18:01Z

r? @eddyb

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petrochenkov · 2019-08-17T23:54:16Z

@bors try

bors · 2019-08-17T23:54:27Z

⌛ Trying commit d73c85e with merge 81ebaa6...

syntax: Support modern attribute syntax in the `meta` matcher Where "modern" means #57367: ``` PATH PATH `(` TOKEN_STREAM `)` PATH `[` TOKEN_STREAM `]` PATH `{` TOKEN_STREAM `}` ``` Unfortunately, `meta` wasn't future-proofed using the `FOLLOW` token set like other matchers (#34011), so code like `$meta:meta {` or `$meta:meta [` may break, and we need a crater run to find out how often this happens in practice. Closes #49629 (by fully supporting `meta` rather than removing it.)

bors · 2019-08-18T02:40:09Z

☀️ Try build successful - checks-azure
Build commit: 81ebaa6

Centril · 2019-08-18T07:50:27Z

Hah; the crater queue is getting crazy, oh well =P

@craterbot run mode=check-only

craterbot · 2019-08-18T07:50:28Z

👌 Experiment pr-63674 created and queued.
🤖 Automatically detected try build 81ebaa6
🔍 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

petrochenkov · 2019-08-18T10:09:23Z

the crater queue is getting crazy

That's a problem with the number of crater instances first of all.

(Two was enough to keep the queue almost empty, but with one it looks like it's going to grow to infinity, so the average PR stream "density" should be somewhere in between.)

sgrif · 2019-08-18T20:21:30Z

so code like $meta:meta { or $meta:meta [ may break, and we need a crater run to find out how often this happens in practice.

This sentiment concerns me. Crater can tell you if a breaking change does affect code, but it can't tell you that a breaking change doesn't affect code. It's one thing if we're talking about a bugfix or soundness change and introducing a necessary breaking change because of that, using crater to mitigate the impact. But this is clearly a new feature, and I don't think we should consider breaking any Rust code to support it acceptable, even if none of the code checked by crater is affected. Folks use Rust because it has strong stability guarantees, and we should be trying to uphold that.

Centril · 2019-08-18T20:33:40Z

@sgrif For language team praxis, please see: #60932 (comment), #53668 (comment), #53668 (comment), and #53668 (comment).

sgrif · 2019-08-18T20:54:11Z

I agree with

Seperately, I think it would be useful to open an RFC that makes this "practical definition" of breaking changes more explicit and tries to narrow down and layout the criteria when what is a "breaking change" (versus a "change that theoretically breaks") -- the rustc bug fix procedure does exactly this, but in a narrower context.

from one of those comments. Until then, please forgive me for pointing this out when I see it, as I continue to find it troubling <3

craterbot · 2019-09-08T09:49:23Z

🚧 Experiment pr-63674 is now running on agent aws-1.

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

pietroalbini · 2019-09-08T10:17:41Z

@craterbot abort

craterbot · 2019-09-08T10:17:46Z

🗑️ Experiment pr-63674 deleted!

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

pietroalbini · 2019-09-08T10:18:00Z

@craterbot run mode=check-only p=1

craterbot · 2019-09-08T10:18:03Z

👌 Experiment pr-63674 created and queued.
🤖 Automatically detected try build 81ebaa6
🔍 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

pietroalbini · 2019-09-08T11:27:16Z

@craterbot crates=full

rfcbot · 2019-09-29T19:24:06Z

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.

petrochenkov · 2019-09-30T22:14:37Z

@bors r=Centril

bors · 2019-09-30T22:14:38Z

📌 Commit 6ea4a52 has been approved by Centril

syntax: Support modern attribute syntax in the `meta` matcher Where "modern" means rust-lang#57367: ``` PATH PATH `(` TOKEN_STREAM `)` PATH `[` TOKEN_STREAM `]` PATH `{` TOKEN_STREAM `}` ``` Unfortunately, `meta` wasn't future-proofed using the `FOLLOW` token set like other matchers (rust-lang#34011), so code like `$meta:meta {` or `$meta:meta [` may break, and we need a crater run to find out how often this happens in practice. Closes rust-lang#49629 (by fully supporting `meta` rather than removing it.)

@ghost

Rollup of 10 pull requests Successful merges: - #63674 (syntax: Support modern attribute syntax in the `meta` matcher) - #63931 (Stabilize macros in some more positions) - #64887 (syntax: recover trailing `|` in or-patterns) - #64895 (async/await: improve not-send errors) - #64896 (Remove legacy grammar) - #64907 (A small amount of tidying-up factored out from PR #64648) - #64928 (Add tests for some issues) - #64930 (Silence unreachable code lint from await desugaring) - #64935 (Improve code clarity) - #64937 (Deduplicate closure type errors) Failed merges: r? @ghost

Manishearth · 2019-10-02T01:32:03Z

This may be causing an ICE #64964

ghost · 2019-10-02T02:41:06Z

The ICE still happens, assuming I properly reverted this PR by applying it in patch form.

So, must be some other PR then? (hope clean build dir wasn't required)

Version 1.40.0 (2019-12-19) =========================== Language -------- - [You can now use tuple `struct`s and tuple `enum` variant's constructors in `const` contexts.][65188] e.g. ```rust pub struct Point(i32, i32); const ORIGIN: Point = { let constructor = Point; constructor(0, 0) }; ``` - [You can now mark `struct`s, `enum`s, and `enum` variants with the `#[non_exhaustive]` attribute to indicate that there may be variants or fields added in the future.][64639] For example this requires adding a wild-card branch (`_ => {}`) to any match statements on a non-exhaustive `enum`. [(RFC 2008)] - [You can now use function-like procedural macros in `extern` blocks and in type positions.][63931] e.g. `type Generated = macro!();` - [Function-like and attribute procedural macros can now emit `macro_rules!` items, so you can now have your macros generate macros.][64035] - [The `meta` pattern matcher in `macro_rules!` now correctly matches the modern attribute syntax.][63674] For example `(#[$m:meta])` now matches `#[attr]`, `#[attr{tokens}]`, `#[attr[tokens]]`, and `#[attr(tokens)]`. Compiler -------- - [Added tier 3 support\* for the `thumbv7neon-unknown-linux-musleabihf` target.][66103] - [Added tier 3 support for the `aarch64-unknown-none-softfloat` target.][64589] - [Added tier 3 support for the `mips64-unknown-linux-muslabi64`, and `mips64el-unknown-linux-muslabi64` targets.][65843] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries --------- - [The `is_power_of_two` method on unsigned numeric types is now a `const` function.][65092] Stabilized APIs --------------- - [`BTreeMap::get_key_value`] - [`HashMap::get_key_value`] - [`Option::as_deref_mut`] - [`Option::as_deref`] - [`Option::flatten`] - [`UdpSocket::peer_addr`] - [`f32::to_be_bytes`] - [`f32::to_le_bytes`] - [`f32::to_ne_bytes`] - [`f64::to_be_bytes`] - [`f64::to_le_bytes`] - [`f64::to_ne_bytes`] - [`f32::from_be_bytes`] - [`f32::from_le_bytes`] - [`f32::from_ne_bytes`] - [`f64::from_be_bytes`] - [`f64::from_le_bytes`] - [`f64::from_ne_bytes`] - [`mem::take`] - [`slice::repeat`] - [`todo!`] Cargo ----- - [Cargo will now always display warnings, rather than only on fresh builds.][cargo/7450] - [Feature flags (except `--all-features`) passed to a virtual workspace will now produce an error.][cargo/7507] Previously these flags were ignored. - [You can now publish `dev-dependencies` without including a `version`.][cargo/7333] Misc ---- - [You can now specify the `#[cfg(doctest)]` attribute to include an item only when running documentation tests with `rustdoc`.][63803] Compatibility Notes ------------------- - [As previously announced, any previous NLL warnings in the 2015 edition are now hard errors.][64221] - [The `include!` macro will now warn if it failed to include the entire file.][64284] The `include!` macro unintentionally only includes the first _expression_ in a file, and this can be unintuitive. This will become either a hard error in a future release, or the behavior may be fixed to include all expressions as expected. - [Using `#[inline]` on function prototypes and consts now emits a warning under `unused_attribute` lint.][65294] Using `#[inline]` anywhere else inside traits or `extern` blocks now correctly emits a hard error. [65294]: rust-lang/rust#65294 [66103]: rust-lang/rust#66103 [65843]: rust-lang/rust#65843 [65188]: rust-lang/rust#65188 [65092]: rust-lang/rust#65092 [64589]: rust-lang/rust#64589 [64639]: rust-lang/rust#64639 [64221]: rust-lang/rust#64221 [64284]: rust-lang/rust#64284 [63931]: rust-lang/rust#63931 [64035]: rust-lang/rust#64035 [63674]: rust-lang/rust#63674 [63803]: rust-lang/rust#63803 [cargo/7450]: rust-lang/cargo#7450 [cargo/7507]: rust-lang/cargo#7507 [cargo/7525]: rust-lang/cargo#7525 [cargo/7333]: rust-lang/cargo#7333 [(rfc 2008)]: https://rust-lang.github.io/rfcs/2008-non-exhaustive.html [`f32::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_be_bytes [`f32::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_le_bytes [`f32::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.to_ne_bytes [`f64::to_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_be_bytes [`f64::to_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_le_bytes [`f64::to_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.to_ne_bytes [`f32::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_be_bytes [`f32::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_le_bytes [`f32::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f32.html#method.from_ne_bytes [`f64::from_be_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_be_bytes [`f64::from_le_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_le_bytes [`f64::from_ne_bytes`]: https://doc.rust-lang.org/std/primitive.f64.html#method.from_ne_bytes [`option::flatten`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.flatten [`option::as_deref`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref [`option::as_deref_mut`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.as_deref_mut [`hashmap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.HashMap.html#method.get_key_value [`btreemap::get_key_value`]: https://doc.rust-lang.org/std/collections/struct.BTreeMap.html#method.get_key_value [`slice::repeat`]: https://doc.rust-lang.org/std/primitive.slice.html#method.repeat [`mem::take`]: https://doc.rust-lang.org/std/mem/fn.take.html [`udpsocket::peer_addr`]: https://doc.rust-lang.org/std/net/struct.UdpSocket.html#method.peer_addr [`todo!`]: https://doc.rust-lang.org/std/macro.todo.html

cuviper · 2020-02-18T19:16:12Z

so code like $meta:meta { or $meta:meta [ may break

We just discovered that this change broke mac's $cfg:meta $t:block -- reem/rust-mac#15 -- but the crate was masked from the crater run due to existing errors from deny(warnings).

rust-highfive assigned eddyb Aug 17, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Aug 17, 2019

petrochenkov added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 17, 2019

petrochenkov mentioned this pull request Aug 17, 2019

Remove $:meta matcher in decl macros #49629

Closed

Centril added relnotes Marks issues that should be documented in the release notes of the next release. T-lang Relevant to the language team, which will review and decide on the PR/issue. needs-fcp This change is insta-stable, so needs a completed FCP to proceed. labels Aug 18, 2019

Centril added this to the 1.39 milestone Aug 18, 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 Sep 8, 2019

craterbot added S-waiting-on-crater Status: Waiting on a crater run to be completed. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 8, 2019

rfcbot added the finished-final-comment-period The final comment period is finished for this PR / Issue. label Sep 29, 2019

rfcbot removed the final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. label Sep 29, 2019

petrochenkov 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-team Status: Awaiting decision from the relevant subteam (see the T-<team> label). labels Sep 30, 2019

petrochenkov added 3 commits September 30, 2019 22:36

syntax: Split ast::Attribute into container and inner parts

535d474

syntax: Support modern attribute syntax in the meta matcher

957986d

Address review comments

6ea4a52

petrochenkov force-pushed the meta2 branch from d73c85e to 6ea4a52 Compare September 30, 2019 22:11

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 Sep 30, 2019

Centril mentioned this pull request Oct 1, 2019

Rollup of 9 pull requests #64944

Closed

Centril mentioned this pull request Oct 1, 2019

Rollup of 10 pull requests #64946

Merged

bors merged commit 6ea4a52 into rust-lang:master Oct 1, 2019

ehuss mentioned this pull request Oct 1, 2019

Update for new meta fragment syntax rust-lang/reference#688

Closed

ghost mentioned this pull request Oct 2, 2019

ICE while compiling hyper (StableHasher: unexpected region '_#0r) #64964

Closed

mystor referenced this pull request in mystor/synstructure Nov 6, 2019

Add documentation and make matchers more flexible

2d9479a

petrochenkov mentioned this pull request Dec 12, 2019

Stabilize attribute macros on inline modules #64273

Merged

cuviper mentioned this pull request Feb 18, 2020

One of tests is broken reem/rust-mac#15

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syntax: Support modern attribute syntax in the `meta` matcher #63674

syntax: Support modern attribute syntax in the `meta` matcher #63674

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syntax: Support modern attribute syntax in the meta matcher #63674

syntax: Support modern attribute syntax in the meta matcher #63674

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syntax: Support modern attribute syntax in the `meta` matcher #63674

syntax: Support modern attribute syntax in the `meta` matcher #63674

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