Rust-analyser not processing results from next() method of async_std::stream::StreamExt

[SillyMoo]

Rust analyser is not able to process the next() method at the end of the attached rust file. This works ok with vs-code and rls, but vs-code with rust-analyzer it fails to return a type for the result of next().

src.zip

[bjorn3]

Maybe a duplicate of #1791? (types wrong with async/await)

Content of the zip, for mobile users

use async_amqp::*;
use async_std::stream::StreamExt;
use lapin::{
    message::DeliveryResult, options::*, publisher_confirm::Confirmation, types::FieldTable,
    BasicProperties, Connection, ConnectionProperties, Result,
};
use log::info;
use futures::channel::mpsc;
use futures::sink::SinkExt;

struct TaskProperty {
    name: String,
    sval: Option<String>,
    nval: Option<i32>,
}
struct Task {
    task_id: String,
    task_ulid: String,
    sample_id: String,
    vm_profile: String,
    task_properties: Vec<TaskProperty>,
}

#[async_std::main]
async fn main() -> Result<()> {

    env_logger::init();
    
    let (tx, mut rx)= mpsc::channel::<String>(100);


    let addr = "amqp://localhost:5673";
    let conn = Connection::connect(&addr, ConnectionProperties::default().with_async_std()).await?;
    let queue_name = "bob";
    info!("CONNECTED");

    let channel_a = conn.create_channel().await?;
    let channel_b = conn.create_channel().await?;

    let queue = channel_a
        .queue_declare(
            queue_name,
            QueueDeclareOptions::default(),
            FieldTable::default(),
        )
        .await?;

    info!("Declared queue {:?}", queue);

    let consumer = channel_b
        .clone()
        .basic_consume(
            queue_name,
            "my_consumer",
            BasicConsumeOptions::default(),
            FieldTable::default(),
        )
        .await?;

    consumer.set_delegate(move |delivery: DeliveryResult| {
        let channel_b = channel_b.clone();
        let mut tx = tx.clone();
        async move {
            let delivery = delivery.expect("error caught in in consumer");
            if let Some(delivery) = delivery {
                channel_b
                    .basic_ack(delivery.delivery_tag, BasicAckOptions::default())
                    .await
                    .expect("failed to ack");
                tx.send(String::from_utf8(delivery.data).unwrap()).await.unwrap();
            }
        }
    });

    let payload = b"Hello world!";

    
    let confirm = channel_a
        .basic_publish(
            "",
            queue_name,
            BasicPublishOptions::default(),
            payload.to_vec(),
            BasicProperties::default(),
        )
        .await?
        .await?;
    assert_eq!(confirm, Confirmation::NotRequested);
    let res = rx.next().await.unwrap();
    info!("Got {:?}", res);
    Ok(())
}

[package]
name = "ivm2_rust"
version = "0.1.0"
authors = ["Chris Mills <Chris_Mills@symantec.com>"]
edition = "2018"

[dependencies]
smol = "0.1.4"
log = "0.4.8"
async-amqp = "0.1.0-beta3"
env_logger = "0.7.1"
futures = "0.3.4"

[dependencies.async-std]
version = "^1.0"
features = ["default"]

[dev-dependencies.async-std]
version = "^1.0"
features = ["attributes", "default"]

[dependencies.lapin]
version = "1.0.0-beta3"
default-features = true

[SillyMoo]

It's worth noting that the failure is at the call to next() rather than the call to await. So not quite sure if it is the same thing.

[flodiebold]

It looks to me like we're not managing to expand the extension_trait! macro.

[edwin0cheng]

Yeah, it is related to #4039

[edwin0cheng]

@SillyMoo #4283 is landed, and it should fix this issue.

[SillyMoo]

Great stuff, thanks.

[lnicola]

Update: we still don't resolve next.

Or maybe we do, but it doesn't work on my system (#4676).

[lnicola]

Triage: this still happens. It looks like we still don't expand that macro correctly:

[lnicola]

A first step here might be to extract extension_trait! macro and see if we can come up with a smaller reproducible example.

[lnicola]

Somewhat minimized test case:

macro_rules! extension_trait {
    (

        pub trait $name:ident {
            $($body_base:tt)*
        }
    ) => {

        #[cfg(feature = "docs")]
        pub trait $name {
            extension_trait!(@doc () $($body_base)*);
        }
    };

    (@doc ($($head:tt)*) $token:tt $($tail:tt)*) => {
        extension_trait!(@doc ($($head)* $token) $($tail)*);
    };

    (@doc ($($head:tt)*)) => { $($head)* };
}

extension_trait! {
    pub trait Stream {
        type Item;
    }
}

// Recursive expansion of extension_trait! macro
// ==============================================

#[cfg(feature = "docs")]pub trait Stream {
  extension_trait!(@doc()type Item;
  );
  
}

[lnicola]

CC @edwin0cheng :-)