rustdoc leaks private types in Implementations on Foreign Types

Problem

When a pub trait is implemented on a constructed type—not counting references if those are "type constructors"—that was constructed based on a private type, it is shown in the documentation. Ideally it would not do this as I like private types to not leak into my documentation. The type constructor has to be pub of course (e.g., a slice).

Steps

/// `Foo`.
pub trait Foo {}
/// `Fizz`.
struct Fizz;
impl Foo for [Fizz] {}

cargo doc --open will generate documentation that shows the trait Foo. When clicking on it, it will show impl Foo for [Fizz] under "Implementations on Foreign Types".

Possible Solution(s)

No response

Notes

No response

Version

[zack@laptop src]$ cargo version --verbose
cargo 1.79.0 (ffa9cf99a 2024-06-03)
release: 1.79.0
commit-hash: ffa9cf99a594e59032757403d4c780b46dc2c43a
commit-date: 2024-06-03
host: x86_64-unknown-linux-gnu
libgit2: 1.7.2 (sys:0.18.3 vendored)
libcurl: 8.6.0-DEV (sys:0.4.72+curl-8.6.0 vendored ssl:OpenSSL/1.1.1w)
ssl: OpenSSL 1.1.1w  11 Sep 2023
os: Arch Linux [64-bit]

Reproduce the issue with the Rust snippet and run cargo doc --open to inspect the generated "Implementations on Foreign Types" entry. Start at the rustdoc handling for implementations involving constructed types, then verify that impls based on private types are omitted while valid public implementations remain documented.