Ran into an issue where clippy was complaining about a crate being compiled against a wrong rustc even though "cargo check" ran successfully.
Turns out if you have a rust version installed via homebrew clippy can choose the incorrect one.
GH Issue: https://github.com/rust-lang/rust-clippy/issues/9560
Tracked down why rustc might be installed by homebrew. I was playing with cargo-nextest as an alternate test runner. The recommended install path was to use homebrew. That package has a dependency on homebrew rust.
To remove:
homebrew remove cargo-nextest rust