821d50aa0c
Warn about unused expressions with closure or generator type. This follows
existing precedence of must use annotations present on `FnOnce`, `FnMut`, `Fn`
traits, which already indirectly apply to closures in some cases, e.g.,:
```rust
fn f() -> impl FnOnce() {
|| {}
}
fn main() {
// an existing warning: unused implementer of `std::ops::FnOnce` that must be used:
f();
// a new warning: unused closure that must be used:
|| {};
}
```
20 lines
482 B
Plaintext
20 lines
482 B
Plaintext
warning: unused variable: `x`
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--> $DIR/unboxed-closures-move-mutable.rs:17:17
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LL | move || x += 1;
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| ^
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= note: `#[warn(unused_variables)]` on by default
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= help: did you mean to capture by reference instead?
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warning: unused variable: `x`
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--> $DIR/unboxed-closures-move-mutable.rs:21:17
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LL | move || x += 1;
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| ^
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= help: did you mean to capture by reference instead?
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warning: 2 warnings emitted
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