Use same table join code for both read and list functions

[dullbananas]

This will fix #2763 and might reduce compile time (#3610).

It works by doing the table joins in a closure so that the return type can be inferred. The closure is inside of a function that returns 2 closures for read and list, which both capture and call the closure that has the join logic.

[dessalines]

Nice, this will be great to have.

[dullbananas]

Rustfmt issue: rust-lang/style-team#138

[Nutomic]

No need for a separate file, you should be able to put the cfg attribute directly on the macro. Or otherwise put a mod {} declaration in lib.rs

[dullbananas]

This is now ready to merge if I didn't mess up anything

[dullbananas]

The build time of lemmy_db_views when re-running the first cargo command in fix-clippy changed from 208.4s to 65.6s

[Nutomic]

Fails to compile:

    Checking lemmy_db_views v0.18.1 (/woodpecker/src/github.com/LemmyNet/lemmy/crates/db_views)
error[E0424]: expected value, found module `self`
   --> crates/db_views/src/comment_view.rs:242:10
    |
57  | fn queries<'a>() -> Queries<
    |    ------- this function can't have a `self` parameter
...
242 |       if self.post_id.is_some() {
    |          ^^^^ `self` value is a keyword only available in methods with a `self` parameter

[dessalines]

I really do wish there was a better way to handle this, but oh well. Seems like such a common case, but because our type is so complicated, its near impossible to reverse.

We'll still merge, but if you get some time, ask @weiznich on matrix or here if there really is no better alternative for what we need.

[dullbananas]

It now compiles

[Nutomic]

Thanks!