`clippy::rc_mutex`

Use RefCell inside Rc for single-threaded sharing, or Arc<Mutex<T>> when the value really crosses threads.

What it reads

Clippy, with the compiler behind it. The only pass that compiles.

Ordinary defect.

The tier bounds how severe a rule may be; its category bounds the tier.

Turn it off, or make it blocking, without touching the code it flags:

rust-doctor --rule clippy::rc_mutex=off .
rust-doctor --rule clippy::rc_mutex=error .