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#![warn(clippy::unused_async)]
#![allow(incomplete_features)]
use std::future::Future;
use std::pin::Pin;
mod issue10800 {
#![allow(dead_code, unused_must_use, clippy::no_effect)]
use std::future::ready;
async fn async_block_await() {
//~^ ERROR: unused `async` for function with no await statements
async {
ready(()).await;
};
}
async fn normal_block_await() {
{
{
ready(()).await;
}
}
}
}
mod issue10459 {
trait HasAsyncMethod {
async fn do_something() -> u32;
}
impl HasAsyncMethod for () {
async fn do_something() -> u32 {
1
}
}
}
mod issue9695 {
use std::future::Future;
async fn f() {}
async fn f2() {}
async fn f3() {}
//~^ ERROR: unused `async` for function with no await statements
fn needs_async_fn<F: Future<Output = ()>>(_: fn() -> F) {}
fn test() {
let x = f;
needs_async_fn(x); // async needed in f
needs_async_fn(f2); // async needed in f2
f3(); // async not needed in f3
}
}
async fn foo() -> i32 {
//~^ ERROR: unused `async` for function with no await statements
4
}
async fn bar() -> i32 {
foo().await
}
struct S;
impl S {
async fn unused(&self) -> i32 {
//~^ ERROR: unused `async` for function with no await statements
1
}
async fn used(&self) -> i32 {
self.unused().await
}
}
trait AsyncTrait {
fn trait_method() -> Pin<Box<dyn Future<Output = i32>>>;
}
macro_rules! async_trait_impl {
() => {
impl AsyncTrait for S {
fn trait_method() -> Pin<Box<dyn Future<Output = i32>>> {
async fn unused() -> i32 {
5
}
Box::pin(unused())
}
}
};
}
async_trait_impl!();
fn main() {
foo();
bar();
}
|
