Fix ICE #7012

[camsteffen]

changelog: none

Fixes #7012

[rust-highfive]

r? @giraffate

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[digama0]

This fixes the ICE, but it looks like it might give the wrong result when Self is used in variants. Does this variation on the first example in match_wildcard_for_single_variants.rs correctly trigger the match_wildcard_for_single_variants lint?

#![warn(clippy::match_wildcard_for_single_variants)]
#![allow(dead_code)]

enum Color {
    Red,
    Green,
    Blue,
    Rgb(u8, u8, u8),
}
impl Color {
    fn f(&self) {
        match self {
            Self::Red => (),
            Self::Green => (),
            &Self::Rgb(_, _, _) => (),
            _ => (),
        };
    }
}

fn main() {}

[digama0]

I think, instead of opt_def_id, it should match on if let Res::Def(_, id) | Res::SelfTy(_, Some((id, _))) = res, since opt_def_id returns None on SelfTy for some reason.

[camsteffen]

I'd like to just fix the ICE first. But feel free to file a bug and/or open a PR.

[giraffate]

It looks good!

The test looks to fail because of formatting, so can you update on this?

[camsteffen]

Oops. Fixed.

[giraffate]

@bors r+

Thanks!

[bors]

📌 Commit 7014340 has been approved by giraffate

[bors]

⌛ Testing commit 7014340 with merge a15d987...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: giraffate
Pushing a15d987 to master...