`rustdoc`: "Methods from `Deref`" section references functions from completely unrelated types.

[olson-sean-k]

I recently published a crate with types that implement Deref. On docs.rs, version 0.2.0 of this crate shows incorrect and completely unrelated methods for the Deref implementation for Vec1. I see the same thing when I build the documentation with recent versions of the nightly toolchain locally (including but not limited to 1.78.0-nightly (f4b771bf1 2024-03-14)).

I only expect the methods of this type (Slice1) to show up in the Deref section for Vec1. However, completely unrelated methods like this from this unrelated type are shown in this section, causing a very large, misleading, and mostly useless list of functions to display.

There are some open bugs regarding the "Methods from Deref" section, but none that seem to observe such unrelated functions. Sorry if I missed something and this is a duplicate and thanks for taking a look!

[theemathas]

MCVE:

use std::ops::Deref;

pub struct Common<T>(T);

pub type RefType = Common<i32>;
pub type Unrelated = Common<i64>;

pub struct OwnedType;

impl Deref for OwnedType {
    type Target = RefType;

    fn deref(&self) -> &Self::Target {
        unimplemented!()
    }
}

impl Unrelated {
    pub fn unrelated_method(&self) {}
}

Running cargo doc --open, and navigating to the OwnedType documentation, gives the following:

[theemathas]

Duplicate of #24686

[tgross35]

Thanks @olson-sean-k for filing this issue, and @theemathas for finding the duplicate. Closing as such.

Kind of unfortunate that issue has been around for as long as it has, probably needs somebody to dig a bit and see if solving it has since gotten easier.