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:
|| {};
}
```
17 lines
401 B
Rust
17 lines
401 B
Rust
// run-pass
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#![feature(generators)]
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fn main() {
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static || { //~ WARN unused generator that must be used
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loop {
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// Test that `opt` is not live across the yield, even when borrowed in a loop
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// See https://github.com/rust-lang/rust/issues/52792
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let opt = {
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yield;
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true
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};
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&opt;
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}
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};
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}
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