error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable --> src/main.rs:4:9 | 3 |letx = 5; | -help: consider changing this to be mutable: `mut x` 4 |lety = &mut x; | ^^^ cannot borrow as mutable 左右滑动查看完整代码 3.借用规则 有人可能会有疑问,...
error[E0596]: cannot borrow `x` as mutable, as it is not declared as mutable --> src/main.rs:4:9 | 3 | let x = 5; | - help: consider changing this to be mutable: `mut x` 4 | let y = &mut x; | ^^^ cannot borrow as mutable 1. 2. 3. 4. 5. 6. 7. 3.借用规则...
("{:?}", r1); // 错误 Cannot borrow `r1` as immutable because it is also borrowed as mutable println!("{}", r2); } println!("{}", r1); 你可能会好奇,明明传入方法的是引用类型,为什么前两条报错信息中会显示 *r1?这是因为发生了隐式重借用,r1.len() 实际上是 String::len(&*r1...
error[E0596]: cannot borrow `*some_string` as mutable, as it is behind a `&` reference -->src/main.rs:19:5 | 19 | some_string.push_str(", world"); | ^^^ `some_string` is a `&` reference, so the data it refers to cannot be borrowed as mutable | help: consider changing ...
error[E0501]: cannot borrow `self.runtime` as mutable because previous closure requires unique access --> the_little_things\src\main.rs:28:9 | 28 | self.runtime.block_on(async { | ___^___---___- | | | | | | ___| first borrow ...
Compiling hello_cargo v0.1.0(/Users/zerun.dong/code/rusttest/hello_cargo)error[E0502]:cannot borrow`a`asimmutable because it is also borrowedasmutable-->src/main.rs:4:25|3|leta_ref=&mut a;|---mutable borrow occurs here4|println!("a is {}",a);|^immutable borrow occurs here5|a_...
【Rust问答】借用值的使用是否会影响借用检查的结果,根据借用检查规则,以下代码会报错letmutv=vec![1,2,3,4,5];letthird=&v[0];v.push(6);//cannotborrow`v`asmutablebecauseitisalsoborrowedasimmutableprintln!("thirdis{}",third);但是为什么将最后一行去掉之后,
fnmain(){lets=String::from("Hello World!");lets1_ref=&mut s;lets2_ref=&mut s;// cannot borrow as mutable} 生命周期 一个变量的生命周期从创建的时候开始,到销毁该变量的时候生命周期结束。编译器通过生命周期确保所有的借用都是有效的:即确保借用存在时,原值不会被销毁。在绝大多数情况下,生命周期...
fnmain() {letx=5;lety= &mutx;// 报错 cannot borrow as mutable} 例子: pubtraitMessage{fnsend(&self, msg: &str); }pubstructLimitTracker<'a, T:'a+ Message> { messenger: &'aT, value:usize, max:usize, }impl<'a, T> LimitTracker<'a, T>whereT: Messenger, ...
error: cannot borrow a as mutable because it is also borrowed as immutable &T和&mut T是不能同时使用的, 无论先后顺序,下面的代码一样是错的: let mut a = Box::new(10); let b = &mut a; let c = &a; 编译器就是依靠这样的机制在编译期发现很多问题,避免运行时出错。 以前的一篇文章 写...