The trait MultiConnection is not implemented

[Ludea]

Setup

Versions

• Rust: 1.72.0
• Diesel: 2.1.1
• Diesel_async: 0.4.1
• Database: Mysql / Postgresql
• Operating System Ubuntu 22.04

Feature Flags

• diesel:
• diesel_async: mysql, postresql

Problem Description

I can't use MultiConnection with async Connection

What are you trying to accomplish?

I would like to use MultiConnection trait with async connection

What is the expected output?

No issue

What is the actual output?

the trait diesel::Connection is not implemented for diesel_async::AsyncMysqlConnection

Are you seeing any additional errors?

Steps to reproduce

#[derive(diesel::MultiConnection)]
pub enum InferConnection {
    Pg(AsyncPgConnection),
    Mysql(AsyncMysqlConnection),
}

Checklist

• I have already looked over the issue tracker for similar possible closed issues.

• This issue can be reproduced on Rust's stable channel. (Your issue will be
  closed if this is not the case)
• This issue can be reproduced without requiring a third party crate

[weiznich]

This is expected behavior as the #[derive(MultiConnection)] proc macro is designed to be used with diesel::Connection types and not with async connection types. It's not a focus for me to provide this functionality for the async crate as well. If someone is interested in this I'm happy to review a PR that includes tests + documentation for this. Otherwise it's also possible to implement that outside of diesel-async.