I tried this code:

    use std::path::{Path, PathBuf};

    pub struct Foo(PathBuf);
    impl std::ops::Deref for Foo {
        type Target = Path;
        fn deref(&self) -> &Path { &self.0 }
    }

I expected to see this happen: Rustdoc shows the docs for Path::from_str on the docs for Foo, like it used to in 1.51:

Instead, this happened: Rustdoc does not generate those methods:

Meta

searched nightlies: from nightly-2021-04-01 to nightly-2021-07-30
regressed nightly: nightly-2021-06-16
searched commits: from 539d7bd to 607d6b0
regressed commit: d74b36e

cargo bisect-rustc --script ./docs-exist.sh --start 2021-04-01 

#!/bin/sh
cargo doc
grep 'Methods from Deref' ${CARGO_TARGET_DIR:-target}/doc/hello_world/foo/struct.Foo.html

cc @pnkfelix