Skip parenthesis if . makes statement boundary unambiguous
#134833
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rustbot
added
S-waiting-on-review
compiler-errors
approved these changes
Dec 27, 2024
|
r? compiler-errors @bors r+ rollup |
bors
added
S-waiting-on-bors
matthiaskrgr
added a commit
to matthiaskrgr/rust
that referenced
this pull request
Dec 28, 2024
…r-errors
Skip parenthesis if `.` makes statement boundary unambiguous
There is a rule in the parser that statements and match-arms never end in front of a `.` or `?` token (except when the `.` is really `..` or `..=` or `...`). So some of the leading subexpressions that need parentheses inserted when followed by some other operator like `-` or `+`, do not need parentheses when followed by `.` or `?`.
Example:
```rust
fn main() {
loop {}.to_string() + "";
match () {
_ => loop {}.to_string() + "",
};
}
```
`-Zunpretty=expanded` before:
```console
#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
fn main() {
(loop {}).to_string() + "";
match () { _ => (loop {}).to_string() + "", };
}
```
After:
```console
#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
fn main() {
loop {}.to_string() + "";
match () { _ => loop {}.to_string() + "", };
}
```
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Dec 28, 2024
Rollup of 4 pull requests Successful merges: - rust-lang#134823 (Fix typos) - rust-lang#134827 (Some random region tweaks) - rust-lang#134833 (Skip parenthesis if `.` makes statement boundary unambiguous) - rust-lang#134834 (Skip parenthesis around tuple struct field calls) r? `@ghost` `@rustbot` modify labels: rollup
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Dec 28, 2024
Rollup merge of rust-lang#134833 - dtolnay:leftmostwithdot, r=compiler-errors Skip parenthesis if `.` makes statement boundary unambiguous There is a rule in the parser that statements and match-arms never end in front of a `.` or `?` token (except when the `.` is really `..` or `..=` or `...`). So some of the leading subexpressions that need parentheses inserted when followed by some other operator like `-` or `+`, do not need parentheses when followed by `.` or `?`. Example: ```rust fn main() { loop {}.to_string() + ""; match () { _ => loop {}.to_string() + "", }; } ``` `-Zunpretty=expanded` before: ```console #![feature(prelude_import)] #[prelude_import] use std::prelude::rust_2021::*; #[macro_use] extern crate std; fn main() { (loop {}).to_string() + ""; match () { _ => (loop {}).to_string() + "", }; } ``` After: ```console #![feature(prelude_import)] #[prelude_import] use std::prelude::rust_2021::*; #[macro_use] extern crate std; fn main() { loop {}.to_string() + ""; match () { _ => loop {}.to_string() + "", }; } ```
poliorcetics
pushed a commit
to poliorcetics/rust
that referenced
this pull request
Dec 28, 2024
…r-errors
Skip parenthesis if `.` makes statement boundary unambiguous
There is a rule in the parser that statements and match-arms never end in front of a `.` or `?` token (except when the `.` is really `..` or `..=` or `...`). So some of the leading subexpressions that need parentheses inserted when followed by some other operator like `-` or `+`, do not need parentheses when followed by `.` or `?`.
Example:
```rust
fn main() {
loop {}.to_string() + "";
match () {
_ => loop {}.to_string() + "",
};
}
```
`-Zunpretty=expanded` before:
```console
#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
fn main() {
(loop {}).to_string() + "";
match () { _ => (loop {}).to_string() + "", };
}
```
After:
```console
#![feature(prelude_import)]
#[prelude_import]
use std::prelude::rust_2021::*;
#[macro_use]
extern crate std;
fn main() {
loop {}.to_string() + "";
match () { _ => loop {}.to_string() + "", };
}
```
poliorcetics
pushed a commit
to poliorcetics/rust
that referenced
this pull request
Dec 28, 2024
Rollup of 4 pull requests Successful merges: - rust-lang#134823 (Fix typos) - rust-lang#134827 (Some random region tweaks) - rust-lang#134833 (Skip parenthesis if `.` makes statement boundary unambiguous) - rust-lang#134834 (Skip parenthesis around tuple struct field calls) r? `@ghost` `@rustbot` modify labels: rollup
dtolnay
removed
the
S-waiting-on-bors
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There is a rule in the parser that statements and match-arms never end in front of a
.or?token (except when the.is really..or..=or...). So some of the leading subexpressions that need parentheses inserted when followed by some other operator like-or+, do not need parentheses when followed by.or?.Example:
-Zunpretty=expandedbefore:After: