Fill match arms duplicates arm with imported variants

[lnicola]

Spotted in #15143.

            ProjectionElem::Field(f) => match &base.data(Interner).kind {
                TyKind::Adt(_, subst) => {
                    db.field_types(f.parent)[f.local_id].clone().substitute(Interner, subst)
                }
                chalk_ir::TyKind::Adt(_, _) => todo!(),
                // ...

[lnicola]

Minimal repro:

mod m {
    pub enum E {
        A,
    }
}

use m::E::{self, *};

fn foo(e: E) {
    match e {
        E::A => {}
    }
}

[alibektas]

@rustbot claim

[jbr]

@alibektas Is there anything I can do to help resolve this? I'm the reporter of #15143 and am unable to use rust-analyzer in my work codebase because it panics almost constantly. My hunch is that the code in question is proc-macro code from sea-orm, but I don't know how to inspect the specific code that RA is looking at when it panics. I don't believe I have any code that looks like the minimal repro

[alibektas]

@jbr let me work on this for the next couple of hours and I will let you know either at the end of my day ( UTC+2 ) or tomorrow. Perhaps you could let me know whether the problem still continues once this is issue is closed.

[alibektas]

@jbr So I checked what the problem is. This issue has a link to #15143 because the problem was encountered while trying to understand the causes of #15143. I will try to solve the original issue, but I am inexperienced in HIR matters but let's see.