Skip parenthesis if . makes statement boundary unambiguous
#134833
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r? compiler-errors @bors r+ rollup |
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…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
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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
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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
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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: