Unexpected behavior when using `Rc` with `RefCell` in a Rust multi-threaded context
I'm trying to configure I'm experimenting with I'm trying to debug Could someone explain Does anyone know how to I'm encountering an issue while trying to share a mutable state across threads using `Rc<RefCell<T>>`. My intention is to share a counter across multiple threads, incrementing its value every time a thread accesses it. However, I'm getting a runtime panic with the message `borrow of borrowed data occurs here` when trying to mutate the value. I attempted the following implementation using the `std::thread` module to spawn multiple threads: ```rust use std::rc::Rc; use std::cell::RefCell; use std::thread; fn main() { let counter = Rc::new(RefCell::new(0)); let mut handles = vec![]; for _ in 0..10 { let counter_clone = Rc::clone(&counter); let handle = thread::spawn(move || { for _ in 0..1000 { let mut num = counter_clone.borrow_mut(); *num += 1; } }); handles.push(handle); } for handle in handles { handle.join().unwrap(); } println!("Final counter value: {}", *counter.borrow()); } ``` This approach works fine in a single-threaded context, but when I try to run it with multiple threads, I face the aforementioned panic. I understand that `Rc` is not thread-safe, and that's likely part of the issue, but I haven't found a straightforward way to adapt my code. I've tried replacing `Rc` with `Arc`, but I still ran into borrowing issues. Is there a recommended pattern for sharing mutable state in a thread-safe manner using `RefCell`? Should I be using a different synchronization primitive altogether? Any guidance on best practices for this scenario would be greatly appreciated. I'm working with Rust in a Docker container on Ubuntu 20.04. What are your experiences with this? The stack includes Rust and several other technologies. Is this even possible? I recently upgraded to Rust 3.10. Thanks in advance! This issue appeared after updating to Rust latest.