RS.CLIPPY.MANUAL_ASYNC_FN

Manual implementations of `async` functions can be simplified using the dedicated syntax

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: manual_async_fn. Copyright ©2025 The Rust Team. All rights reserved.

What it does

It checks for manual implementations of async functions.

Why is this bad?

It's more idiomatic to use the dedicated syntax.

Example

use std::future::Future;

fn foo() -> impl Future<Output = i32> { async { 42 } }

Use instead:

async fn foo() -> i32 { 42 }