error.txt

   Compiling testproject v0.1.0 (/tmp/testproject)
error[E0277]: the trait bound `std::future::GenFuture<[static generator@src/main.rs:8:31: 8:41 x:_ _]>: std::marker::Unpin` is not satisfied in `impl core::future::future::Future`
  --> src/main.rs:10:39
   |
10 |     while let Some(stream) = incoming.next().await {
   |                                       ^^^^ within `impl core::future::future::Future`, the trait `std::marker::Unpin` is not implemented for `std::future::GenFuture<[static generator@src/main.rs:8:31: 8:41 x:_ _]>`
   |
   = help: the following implementations were found:
             <std::future::GenFuture<T> as std::marker::Unpin>
   = note: required because it appears within the type `impl core::future::future::Future`
   = note: required because of the requirements on the impl of `std::marker::Unpin` for `futures_util::stream::stream::filter_map::FilterMap<tokio::net::tcp::incoming::Incoming<'_>, impl core::future::future::Future, [closure@src/main.rs:8:21: 8:41]>`

error[E0277]: the trait bound `std::future::GenFuture<[static generator@src/main.rs:8:31: 8:41 x:_ _]>: std::marker::Unpin` is not satisfied in `impl core::future::future::Future`
   --> src/main.rs:10:30
    |
10  |     while let Some(stream) = incoming.next().await {
    |                              ^^^^^^^^^^^^^^^^^^^^^ within `impl core::future::future::Future`, the trait `std::marker::Unpin` is not implemented for `std::future::GenFuture<[static generator@src/main.rs:8:31: 8:41 x:_ _]>`
    |
    = help: the following implementations were found:
              <std::future::GenFuture<T> as std::marker::Unpin>
    = note: required because it appears within the type `impl core::future::future::Future`
    = note: required because of the requirements on the impl of `std::marker::Unpin` for `futures_util::stream::stream::filter_map::FilterMap<tokio::net::tcp::incoming::Incoming<'_>, impl core::future::future::Future, [closure@src/main.rs:8:21: 8:41]>`
    = note: required because of the requirements on the impl of `core::future::future::Future` for `futures_util::stream::stream::next::Next<'_, futures_util::stream::stream::filter_map::FilterMap<tokio::net::tcp::incoming::Incoming<'_>, impl core::future::future::Future, [closure@src/main.rs:8:21: 8:41]>>`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.
error: could not compile `testproject`.

To learn more, run the command again with --verbose.

main.rs

use tokio::net::TcpListener;
use futures::stream::StreamExt;
use std::error::Error;

async fn listen() -> Result<(), Box<dyn Error>> {
    let mut listener = TcpListener::bind("127.0.0.1:8000").await?;
    let mut incoming = listener.incoming()
        .filter_map(|x| async { x.ok() });

    while let Some(stream) = incoming.next().await {

    }

    Ok(())
}

#[tokio::main]
async fn main() {
    listen().await;
}