Rc<RefCell<T>>のTを編集できない `Rc``RefCell` use std::borrow::BorrowMut; use std::cell::RefCell; use std::rc::Rc; #[derive(Debug)] struct Test { num: i32, } fn main() { let a = Rc::new(RefCell::new(Test { num: 100 })); let a1 = a.clone(); a.borrow_mut().num = 100; a1.borrow_mut().num = 100; println!("a: {:?}", a); println!("a1: {:?}", a1); } 100 error[E0609]: no field `num` on type `&mut Rc<RefCell<Test>>` --> src/main.rs:13:20 | 13 | a.borrow_mut().num = 100; | ^^^ unknown field Rust Cell, RefCell `Test`

error[E0609]: no field `num` on type `&mut Rc>`


RefCell::borrow_mut .num Rc BorrowMut::borrow_mut
BorrowMut use Rc borrow_mut (deref) RefCell borrow_mut