a16722d221
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
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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.
20 lines
508 B
Rust
20 lines
508 B
Rust
#![feature(stmt_expr_attributes)]
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fn foo() -> String {
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#[cfg(feature = "validation")]
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[1, 2, 3].iter().map(|c| c.to_string()).collect::<String>() //~ ERROR expected `;`, found `#`
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#[cfg(not(feature = "validation"))]
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String::new()
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}
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fn bar() -> String {
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#[attr]
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[1, 2, 3].iter().map(|c| c.to_string()).collect::<String>() //~ ERROR expected `;`, found `#`
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#[attr] //~ ERROR cannot find attribute `attr` in this scope
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String::new()
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}
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fn main() {
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println!("{}", foo());
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}
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