`rustdoc` emits spurious build errors due to unsatisfied trait bounds on code that compiles fine

I tried this code: https://github.com/zopfli-rs/zopfli/pull/36

I expected to see this happen: the CI build workflow completes fine.

Instead, this happened: the CI build workflow run failed to build the crate documentation. However, the crate compiles without any problems when using cargo test and cargo build with the same features:

I suspect there's a new issue with the latest nightly rustdoc, leading to unexpected trait bound errors. This suspicion stems from the fact that the same command works well under rustc 1.75.0-nightly (df871fbf0 2023-10-24). Additionally, there have been recent changes made to the code that rustdoc accepts: https://github.com/rust-lang/rust/issues/117622, https://github.com/rust-lang/rust/pull/117450

Meta

rustc --version --verbose:

rustc 1.75.0-nightly (0f44eb32f 2023-11-09)
binary: rustc
commit-hash: 0f44eb32f1123ac93ab404d74c295263ce468343
commit-date: 2023-11-09
host: x86_64-unknown-linux-gnu
release: 1.75.0-nightly
LLVM version: 17.0.4

Reproduce the failure using the linked zopfli-rs/zopfli pull request and the recorded nightly rustc version, comparing rustdoc with cargo test and cargo build under the same features. Trace the rustdoc diagnostics for the unsatisfied trait bounds; done means the crate documentation builds without errors when the crate itself compiles successfully.