rust/tests/ui/redundant_async_block.rs

112 lines
2.5 KiB
Rust

// run-rustfix
#![allow(unused)]
#![warn(clippy::redundant_async_block)]
use std::future::Future;
async fn func1(n: usize) -> usize {
n + 1
}
async fn func2() -> String {
let s = String::from("some string");
let f = async { (*s).to_owned() };
let x = async { f.await };
x.await
}
macro_rules! await_in_macro {
($e:expr) => {
std::convert::identity($e).await
};
}
async fn func3(n: usize) -> usize {
// Do not lint (suggestion would be `std::convert::identity(func1(n))`
// which copies code from inside the macro)
async move { await_in_macro!(func1(n)) }.await
}
// This macro should never be linted as `$e` might contain `.await`
macro_rules! async_await_parameter_in_macro {
($e:expr) => {
async { $e.await }
};
}
// MISSED OPPORTUNITY: this macro could be linted as the `async` block does not
// contain code coming from the parameters
macro_rules! async_await_in_macro {
($f:expr) => {
($f)(async { func2().await })
};
}
fn main() {
let fut1 = async { 17 };
let fut2 = async { fut1.await };
let fut1 = async { 25 };
let fut2 = async move { fut1.await };
let fut = async { async { 42 }.await };
// Do not lint: not a single expression
let fut = async {
func1(10).await;
func2().await
};
// Do not lint: expression contains `.await`
let fut = async { func1(func2().await.len()).await };
let fut = async_await_parameter_in_macro!(func2());
let fut = async_await_in_macro!(std::convert::identity);
}
#[allow(clippy::let_and_return)]
fn capture_local() -> impl Future<Output = i32> {
// Lint
let fut = async { 17 };
async move { fut.await }
}
fn capture_local_closure(s: &str) -> impl Future<Output = &str> {
let f = move || std::future::ready(s);
// Do not lint: `f` would not live long enough
async move { f().await }
}
#[allow(clippy::let_and_return)]
fn capture_arg(s: &str) -> impl Future<Output = &str> {
// Lint
let fut = async move { s };
async move { fut.await }
}
#[derive(Debug, Clone)]
struct F {}
impl F {
async fn run(&self) {}
}
pub async fn run() {
let f = F {};
let c = f.clone();
// Do not lint: `c` would not live long enough
spawn(async move { c.run().await });
let _f = f;
}
fn spawn<F: Future + 'static>(_: F) {}
async fn work(_: &str) {}
fn capture() {
let val = "Hello World".to_owned();
// Do not lint: `val` would not live long enough
spawn(async { work(&{ val }).await });
}