rust/tests/ui/parser/attribute/multiple-tail-expr-behind-cfg.rs, branch 1.90.0
https://github.com/rust-lang/rust
http://git.dreamy.place/mirrors/rust/atom?h=1.90.0
2025-04-03T21:41:58+00:00
Use `cfg(false)` in UI tests
2025-04-03T21:41:58+00:00
clubby789
jamie@hill-daniel.co.uk
2025-03-29T17:24:03+00:00
urn:sha1:303c1b45c29f8bb186a9a95cb56643d1aef773fa
Unify all the always-false cfgs under the `FALSE` cfg
2024-04-06T23:16:45+00:00
Urgau
urgau@numericable.fr
2024-04-06T22:43:00+00:00
urn:sha1:c4a97d9407556081c5a8d8927ef86529b3bf4572
Handle attempts to have multiple `cfg`d tail expressions
2023-11-16T21:21:26+00:00
Esteban Küber
esteban@kuber.com.ar
2023-11-16T21:21:26+00:00
urn:sha1:a16722d2210caa5eea941ffa20837859e249fd05
When encountering code that seems like it might be trying to have
multiple tail expressions depending on `cfg` information, suggest
alternatives that will success to parse.
```rust
fn foo() -> String {
#[cfg(feature = "validation")]
[1, 2, 3].iter().map(|c| c.to_string()).collect::<String>()
#[cfg(not(feature = "validation"))]
String::new()
}
```
```
error: expected `;`, found `#`
--> $DIR/multiple-tail-expr-behind-cfg.rs:5:64
|
LL | #[cfg(feature = "validation")]
| ------------------------------ only `;` terminated statements or tail expressions are allowed after this attribute
LL | [1, 2, 3].iter().map(|c| c.to_string()).collect::<String>()
| ^ expected `;` here
LL | #[cfg(not(feature = "validation"))]
| - unexpected token
|
help: add `;` here
|
LL | [1, 2, 3].iter().map(|c| c.to_string()).collect::<String>();
| +
help: alternatively, consider surrounding the expression with a block
|
LL | { [1, 2, 3].iter().map(|c| c.to_string()).collect::<String>() }
| + +
help: it seems like you are trying to provide different expressions depending on `cfg`, consider using `if cfg!(..)`
|
LL ~ if cfg!(feature = "validation") {
LL ~ [1, 2, 3].iter().map(|c| c.to_string()).collect::<String>()
LL ~ } else if cfg!(not(feature = "validation")) {
LL ~ String::new()
LL + }
|
```
Fix #106020.