dead_code warning not emitted for unused associated constant

[Freax13]

Code

I tried this code:

struct Foo(u16);

pub fn use_foo() {
    let _ = Foo(0);
}

impl Foo {
    pub const BAR: Self = Self(123);
}

impl PartialEq<Foo> for u16 {
    fn eq(&self, other: &Foo) -> bool {
        *self == other.0
    }
}

I expected to see this happen: I expected to see a dead_code warning for Foo::BAR.

Instead, this happened: No warning is emitted.

Version it worked on

It most recently worked on: Rust 1.70

Version with regression

rustc --version --verbose:

rustc 1.71.1 (eb26296b5 2023-08-03)
binary: rustc
commit-hash: eb26296b556cef10fb713a38f3d16b9886080f26
commit-date: 2023-08-03
host: x86_64-unknown-linux-gnu
release: 1.71.1
LLVM version: 16.0.5

Backtrace

N/A

@rustbot modify labels: +regression-from-stable-to-stable -regression-untriaged

[Freax13]

searched nightlies: from nightly-2023-03-04 to nightly-2023-05-27
regressed nightly: nightly-2023-05-15
searched commit range: 2c41369...18bfe5d
regressed commit: ad6ab11

bisected with cargo-bisect-rustc v0.6.6

Host triple: x86_64-unknown-linux-gnu
Reproduce with:

cargo bisect-rustc --start 1.69.0 --end 1.71.0 --regress success --access github -vvvvv -c clippy -- clippy -- -D warnings 

[lqd]

That's #111425, cc PR author @Bryanskiy and reviewer @petrochenkov

[Bryanskiy]

Fixed in #112670

[apiraino]

WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-medium

[lqd]

Indeed, it's fixed on nightly, as well as beta. The fix will land on stable in 12 days. I'll close this but feel free to reopen in the highly unlikely chance that it appears on the next stable.

Thanks for opening an issue!