Error: the trait tokio::io::async_read::AsyncRead is not implemented for tokio::net::TcpStream

[Urhengulas]

Though AsyncRead and AsyncWrite should be implemented for TcpStream (see here) rust tells me that it's not:

error[E0277]: the trait bound `tokio::net::TcpStream: tokio::io::async_read::AsyncRead` is not satisfied
   --> tarpc/src/serde_transport.rs:176:55
    |
176 |             Poll::Ready(Ok(new(self.config.new_framed(io), (self.codec_fn)())))
    |                                                       ^^ the trait `tokio::io::async_read::AsyncRead` is not implemented for `tokio::net::TcpStream`

Corresponding code: https://github.com/google/tarpc/blob/d27f341bdebe29df927b6d2b6f1a26fd657a0efe/tarpc/src/serde_transport.rs#L176

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I also tried to enable the "net"-feature, but this actually changes nothing...

[Darksonn]

I do not get that error when I compile your project at that commit with --all-features.

[Urhengulas]

In the code I linked tokio isn't bumped to 0.3 yet.

But I think I resolved this by next to upgrading tokio to 0.3 also upgrading tokio-util to 0.4..

[taiki-e]

@Urhengulas: You are probably using an old tokio-util. Can you check that tokio-util is 0.4?

[Urhengulas]

@taiki-e This solves the problem!

But I actually don't understand why... Could you please briefly explain this?

[Darksonn]

The TcpStream in Tokio 0.3 implements the AsyncRead trait from Tokio 0.3, but tokio-util 0.3 requires the AsyncRead trait from Tokio 0.2.