/// **Why is this bad?** `Rc` is used in single thread and `Mutex` is used in multi thread.
/// Consider using `Rc<RefCell<T>>` in single thread or `Arc<Mutex<T>>` in multi thread.
///
- /// **Known problems:** Maybe false positive on trait generic.
+ /// **Known problems:** Sometimes combining generic types can lead to the requirement that a
+ /// type use Rc in conjunction with Mutex. We must consider those cases false positives, but
+ /// alas they are quite hard to rule out. Luckily they are also rare.
///
/// **Example:**
/// ```rust,ignore