OnlyDsl::only() does not work together with aliases when doing inner_join

[Ploppz]

Setup

Versions

• Rust: 1.66.1
• Diesel: 2.0.4
• Database: Postgres
• Operating System Arch Linux

Feature Flags

• diesel: "postgres"

Problem

Compiler error when I try to inner join a table with .only() together with an alias of a different table.

use diesel::dsl::OnlyDsl;
use diesel::prelude::*;
use diesel::sql_types::*;
use diesel::{joinable, table};

table! {
    hci.measurement (id) {
        id -> Int8,
    }
}

table! {
    hci.worker_job (id) {
        id -> Int8,
        measurement_id -> Nullable<Int8>,
    }
}

joinable!(worker_job -> measurement (measurement_id));

allow_tables_to_appear_in_same_query!(measurement, worker_job);

fn main() {
    let (worker_job1, worker_job2) =
        diesel::alias!(worker_job as worker_job1, worker_job as worker_job2);

    // Works well:
    measurement::table.only().inner_join(
        worker_job::table.on(worker_job::measurement_id.eq(measurement::id.nullable())),
    );

    // Does not work:
    measurement::table.only().inner_join(
        worker_job1.on(worker_job1
            .field(worker_job::measurement_id)
            .eq(measurement::id.nullable())),
    );
}

Error:

error[E0277]: the trait bound `query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>: AppearsInFromClause<Alias<worker_job1>>` is not satisfied
  --> src/main.rs:33:31
   |
33 |     measurement::table.only().inner_join(
   |                               ^^^^^^^^^^ the trait `AppearsInFromClause<Alias<worker_job1>>` is not implemented for `query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>`
   |
   = help: the trait `AppearsInFromClause<T>` is implemented for `query_source::joins::Join<Left, Right, Kind>`
   = note: required for `AliasedField<worker_job1, worker_job::columns::id>` to implement `AppearsOnTable<query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>>`
   = note: 2 redundant requirements hidden
   = note: required for `((measurement::columns::id,), (AliasedField<worker_job1, worker_job::columns::id>, AliasedField<worker_job1, worker_job::columns::measurement_id>))` to implement `AppearsOnTable<query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>>`
   = note: required for `query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>` to implement `QuerySource`
   = note: 1 redundant requirement hidden
   = note: required for `JoinOn<query_source::joins::Join<Only<measurement::table>, Alias<worker_job1>, Inner>, diesel::expression::grouped::Grouped<diesel::expression::operators::Eq<AliasedField<worker_job1, worker_job::columns::measurement_id>, NullableExpression<measurement::columns::id>>>>` to implement `QuerySource`
   = note: required for `SelectStatement<FromClause<Only<measurement::table>>>` to implement `InternalJoinDsl<Alias<worker_job1>, Inner, diesel::expression::grouped::Grouped<diesel::expression::operators::Eq<AliasedField<worker_job1, worker_job::columns::measurement_id>, NullableExpression<measurement::columns::id>>>>`

Checklist

• I have already looked over the issue tracker and the disussion forum 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

[JainVidit12]

I came across this issue while I am trying to learn rust. Can I take this up?

[weiznich]

@JainVidit12 We are generally happy to get contributions for any open issue, so yes you can take up this one. That written: This issue likely requires debugging some complicated trait setup. I'm not sure whether that's a good issue for someone still learning rust. That shouldn't stop you from working on this issue, I just want to avoid potential frustration.
Now to write something about the actual issue: I would start with checking for similar trait impls that that ones listed in the required for section of the error message. Likely one of the impls there is missing or to restrictive.