Do better with generated defs

[nrc]

This is mostly a rustc/save-analysis issue. When a definition is generated by a macro, we have the span of the macro use which we could use, but either in save-analysis or the RLS we avoid doing this. We have to be a bit careful since in some circumstances this can lead to bad spans and other errors, but at least in some cases this should work. E.g.,

#[derive(new)]
struct Foo { ... }

fn main() {
    Foo::new(...);
}

Goto def on new should jump to the derive(new) span, but currently we get nothing.

[KalitaAlexey]

macro_rules! define_enum {
    () => (
        enum E {
            A,
            B,
            C
        }
    )
}

define_enum!();

fn main() {
    let e = E::A; // Here

    match e {
        E::A => {} // Here
        _ => {}
    }
}

It doesn't find a span for neither E nor E::A.

Is that same problem?

[sophiajt]

I believe this should be filed on the https://github.com/nrc/rls-analysis repo.

@nrc - are you consolidating all the issues here?

[nrc]

rust-dev-tools/rls-analysis#110