Treat trailing semicolon as a statement in macro call#78376

Aaron1011 · 2020-10-25T21:15:41Z

See #61733 (comment)

We now preserve the trailing semicolon in a macro invocation, even if
the macro expands to nothing. As a result, the following code no longer
compiles:

macro_rules! empty {
    () => { }
}

fn foo() -> bool { //~ ERROR mismatched
    { true } //~ ERROR mismatched
    empty!();
}

Previously, { true } would be considered the trailing expression, even
though there's a semicolon in empty!();

This makes macro expansion more token-based.

rust-highfive · 2020-10-25T21:15:45Z

r? @varkor

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

Aaron1011 · 2020-10-25T21:15:50Z

r? @ghost

Aaron1011 · 2020-10-25T21:15:54Z

@bors try

bors · 2020-10-25T21:16:04Z

⌛ Trying commit 6d426c227a0be2819845c1072548536ce540643f with merge 1c5262aa6c045a581fb974488793f09ed51fc498...

bors · 2020-10-25T22:02:09Z

☀️ Try build successful - checks-actions
Build commit: 1c5262aa6c045a581fb974488793f09ed51fc498 (1c5262aa6c045a581fb974488793f09ed51fc498)

Aaron1011 · 2020-10-25T22:17:11Z

@craterbot check

craterbot · 2020-10-25T22:17:15Z

👌 Experiment pr-78376 created and queued.
🤖 Automatically detected try build 1c5262aa6c045a581fb974488793f09ed51fc498
🔍 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

Aaron1011 · 2020-10-25T22:31:27Z

compiler/rustc_expand/src/placeholders.rs

I think this is only observable in the post-expansion AST JSON. When we invoke a bang macro, there are no attribute macros left that could observe this.

craterbot · 2020-10-30T20:57:39Z

🚧 Experiment pr-78376 is now running

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

craterbot · 2020-11-02T16:56:34Z

🎉 Experiment pr-78376 is completed!
📊 4 regressed and 10 fixed (127687 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

Aaron1011 · 2020-11-02T17:36:37Z

There appear to be no actual regressions 🎉

See rust-lang#61733 (comment) We now preserve the trailing semicolon in a macro invocation, even if the macro expands to nothing. As a result, the following code no longer compiles: ```rust macro_rules! empty { () => { } } fn foo() -> bool { //~ ERROR mismatched { true } //~ ERROR mismatched empty!(); } ``` Previously, `{ true }` would be considered the trailing expression, even though there's a semicolon in `empty!();` This makes macro expansion more token-based.

Aaron1011 · 2020-11-02T18:06:18Z

@petrochenkov: This is now ready to merge

petrochenkov · 2020-11-02T21:02:38Z

@bors r+

bors · 2020-11-02T21:02:40Z

📌 Commit e78e9d4 has been approved by petrochenkov

…expr, r=petrochenkov Treat trailing semicolon as a statement in macro call See rust-lang#61733 (comment) We now preserve the trailing semicolon in a macro invocation, even if the macro expands to nothing. As a result, the following code no longer compiles: ```rust macro_rules! empty { () => { } } fn foo() -> bool { //~ ERROR mismatched { true } //~ ERROR mismatched empty!(); } ``` Previously, `{ true }` would be considered the trailing expression, even though there's a semicolon in `empty!();` This makes macro expansion more token-based.

Rollup of 8 pull requests Successful merges: - rust-lang#78376 (Treat trailing semicolon as a statement in macro call) - rust-lang#78400 (Fix unindent in doc comments) - rust-lang#78575 (Add a test for compiletest rustc-env & unset-rustc-env directives) - rust-lang#78616 (Document -Zinstrument-coverage) - rust-lang#78663 (Fix ICE when a future-incompat-report has its command-line level capped) - rust-lang#78664 (Fix intrinsic size_of stable link) - rust-lang#78668 (inliner: Remove redundant loop) - rust-lang#78676 (add mipsel-unknown-none target) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup

bors · 2020-11-03T09:18:28Z

⌛ Testing commit e78e9d4 with merge d662f80...

Pkgsrc changes: * Adjust patches, convert tabs to spaces so that tests pass. * Remove patches which are no longer needed (upstream changed) * Minor adjustments for SunOS, e.g. disable stack probes. * Adjust cargo checksum patching accordingly. * Remove commented-out use of PATCHELF on NetBSD, which doesn't work anyway... Upstream changes: Version 1.49.0 (2020-12-31) ============================ Language ----------------------- - [Unions can now implement `Drop`, and you can now have a field in a union with `ManuallyDrop<T>`.][77547] - [You can now cast uninhabited enums to integers.][76199] - [You can now bind by reference and by move in patterns.][76119] This allows you to selectively borrow individual components of a type. E.g. ```rust #[derive(Debug)] struct Person { name: String, age: u8, } let person = Person { name: String::from("Alice"), age: 20, }; // `name` is moved out of person, but `age` is referenced. let Person { name, ref age } = person; println!("{} {}", name, age); ``` Compiler ----------------------- - [Added tier 1\* support for `aarch64-unknown-linux-gnu`.][78228] - [Added tier 2 support for `aarch64-apple-darwin`.][75991] - [Added tier 2 support for `aarch64-pc-windows-msvc`.][75914] - [Added tier 3 support for `mipsel-unknown-none`.][78676] - [Raised the minimum supported LLVM version to LLVM 9.][78848] - [Output from threads spawned in tests is now captured.][78227] - [Change os and vendor values to "none" and "unknown" for some targets][78951] \* Refer to Rust's [platform support page][forge-platform-support] for more information on Rust's tiered platform support. Libraries ----------------------- - [`RangeInclusive` now checks for exhaustion when calling `contains` and indexing.][78109] - [`ToString::to_string` now no longer shrinks the internal buffer in the default implementation.][77997] - [`ops::{Index, IndexMut}` are now implemented for fixed sized arrays of any length.][74989] Stabilized APIs --------------- - [`slice::select_nth_unstable`] - [`slice::select_nth_unstable_by`] - [`slice::select_nth_unstable_by_key`] The following previously stable methods are now `const`. - [`Poll::is_ready`] - [`Poll::is_pending`] Cargo ----------------------- - [Building a crate with `cargo-package` should now be independently reproducible.][cargo/8864] - [`cargo-tree` now marks proc-macro crates.][cargo/8765] - [Added `CARGO_PRIMARY_PACKAGE` build-time environment variable.] [cargo/8758] This variable will be set if the crate being built is one the user selected to build, either with `-p` or through defaults. - [You can now use glob patterns when specifying packages & targets.][cargo/8752] Compatibility Notes ------------------- - [Demoted `i686-unknown-freebsd` from host tier 2 to target tier 2 support.][78746] - [Macros that end with a semi-colon are now treated as statements even if they expand to nothing.][78376] - [Rustc will now check for the validity of some built-in attributes on enum variants.][77015] Previously such invalid or unused attributes could be ignored. - Leading whitespace is stripped more uniformly in documentation comments, which may change behavior. You read [this post about the changes][rustdoc-ws-post] for more details. - [Trait bounds are no longer inferred for associated types.][79904] 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. - [rustc's internal crates are now compiled using the `initial-exec` Thread Local Storage model.][78201] - [Calculate visibilities once in resolve.][78077] - [Added `system` to the `llvm-libunwind` bootstrap config option.][77703] - [Added `--color` for configuring terminal color support to bootstrap.][79004] [75991]: rust-lang/rust#75991 [78951]: rust-lang/rust#78951 [78848]: rust-lang/rust#78848 [78746]: rust-lang/rust#78746 [78376]: rust-lang/rust#78376 [78228]: rust-lang/rust#78228 [78227]: rust-lang/rust#78227 [78201]: rust-lang/rust#78201 [78109]: rust-lang/rust#78109 [78077]: rust-lang/rust#78077 [77997]: rust-lang/rust#77997 [77703]: rust-lang/rust#77703 [77547]: rust-lang/rust#77547 [77015]: rust-lang/rust#77015 [76199]: rust-lang/rust#76199 [76119]: rust-lang/rust#76119 [75914]: rust-lang/rust#75914 [74989]: rust-lang/rust#74989 [79004]: rust-lang/rust#79004 [78676]: rust-lang/rust#78676 [79904]: rust-lang/rust#79904 [cargo/8864]: rust-lang/cargo#8864 [cargo/8765]: rust-lang/cargo#8765 [cargo/8758]: rust-lang/cargo#8758 [cargo/8752]: rust-lang/cargo#8752 [`slice::select_nth_unstable`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable [`slice::select_nth_unstable_by`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by [`slice::select_nth_unstable_by_key`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.select_nth_unstable_by_key [`hint::spin_loop`]: https://doc.rust-lang.org/stable/std/hint/fn.spin_loop.html [`Poll::is_ready`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_ready [`Poll::is_pending`]: https://doc.rust-lang.org/stable/std/task/enum.Poll.html#method.is_pending [rustdoc-ws-post]: https://blog.guillaume-gomez.fr/articles/2020-11-11+New+doc+comment+handling+in+rustdoc

rust-highfive assigned varkor Oct 25, 2020

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 25, 2020

petrochenkov assigned petrochenkov and unassigned varkor Oct 25, 2020

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 Oct 25, 2020

Aaron1011 commented Oct 25, 2020

View reviewed changes

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 Nov 2, 2020

Aaron1011 changed the title ~~[DO NOT MERGE] Treat trailing semicolon as a statement in macro call~~ Treat trailing semicolon as a statement in macro call Nov 2, 2020

Aaron1011 force-pushed the feature/consistent-empty-expr branch from 6d426c2 to e78e9d4 Compare November 2, 2020 18:05

Aaron1011 added the relnotes Marks issues that should be documented in the release notes of the next release. label Nov 2, 2020

Aaron1011 added the A-proc-macros Area: Procedural macros label Nov 2, 2020

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 Nov 2, 2020

Dylan-DPC-zz mentioned this pull request Nov 3, 2020

Rollup of 9 pull requests #78693

Closed

JohnTitor mentioned this pull request Nov 3, 2020

Rollup of 8 pull requests #78697

Merged

bors merged commit 0716724 into rust-lang:master Nov 3, 2020

rustbot added this to the 1.49.0 milestone Nov 3, 2020

Uh oh!

Conversation

Aaron1011 commented Oct 25, 2020 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rust-highfive commented Oct 25, 2020

Uh oh!

Aaron1011 commented Oct 25, 2020

Uh oh!

Aaron1011 commented Oct 25, 2020

Uh oh!

bors commented Oct 25, 2020

Uh oh!

bors commented Oct 25, 2020

Uh oh!

Aaron1011 commented Oct 25, 2020

Uh oh!

craterbot commented Oct 25, 2020

Uh oh!

Aaron1011 Oct 25, 2020 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

craterbot commented Oct 30, 2020

Uh oh!

craterbot commented Nov 2, 2020

Uh oh!

Aaron1011 commented Nov 2, 2020 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Aaron1011 commented Nov 2, 2020

Uh oh!

petrochenkov commented Nov 2, 2020

Uh oh!

bors commented Nov 2, 2020

Uh oh!

bors commented Nov 3, 2020

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants

Aaron1011 commented Oct 25, 2020 •

edited

Loading

Aaron1011 Oct 25, 2020 •

edited

Loading

Aaron1011 commented Nov 2, 2020 •

edited

Loading