RS.CLIPPY.RC_MUTEX

Usage of `Rc<Mutex<T>>`

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: rc_mutex. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Checks for Rc<Mutex<T>>.

Why restrict this?

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

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

use std::rc::Rc;
use std::sync::Mutex;
fn foo(interned: Rc<Mutex<i32>>) { ... }

Better:

use std::rc::Rc;
use std::cell::RefCell
fn foo(interned: Rc<RefCell<i32>>) { ... }

Configuration

avoid-breaking-exported-api: Suppress lints whenever the suggested change would cause breakage for other crates.

(default: true)