Georg Semmler

From the search linked above it's missing the following impls: * `Insertable for Arc/Rc` * `Migration for Arc/Rc` * `AppearsOnTable for Arc/Rc` * `SelectableExpression for Arc/Rc` * `ValidGrouping for Arc/Rc`...

That's kind of expected that this fails as the list of traits as written above is not designed to enable that use-case, but only `Arc/Rc`. If that other things is...

> Just to better understand, https://github.com/diesel-rs/diesel/discussions/4609 I was asking exactly regarding the use of Rc in such structs, but maybe I had explained myself poorly. Do you believe it should...

> Thank you for your reply - regarding extending the AsExpression derive, I can try to add the Rc and Arc derive impls and report how much the compile time...

> I will go through the comments and update the PR accordingly - regarding the Send/Rc issue, should I open an issue in diesel-async on the topic and, after this...

So I had a look at the relevant code and it seems like that this PR is missing that impl for `Rc` and `Arc`: https://github.com/diesel-rs/diesel/blob/15216dcb1d36fd55bc583c4f7a4704bc53983b7b/diesel/src/expression/mod.rs#L166-L168 This impl enables the `Box`...

> I see you added a distinct() function, e.g. dsl::count(users::id).distinct(), is that functionally the same as count_distinct()? Yes that's the same for `count()`, it just generalizes that to any aggregate...

I pushed an update that brings most of the infrastructure for in place for supporting several backends. This was rather tricky as different backends have different restrictions on which functions...

@diesel-rs/reviewers This PR is now ready to be merged. I'm looking forward to your review here.

Thanks for opening this PR. I'm not sure if that's the best solution as this command line flag sounds like something that fits mostly your workflow, but I do not...