Closed
Description
Compiling this code (playground):
#![feature(nll)]
use std::collections::{HashMap};
fn main() {
let map: HashMap<u32, Vec<u32>> = HashMap::new();
for (_, nodes) in map.iter() {
nodes.retain(|&n| n == 3);
}
}
Gives this error:
error[E0596]: cannot borrow immutable item `*nodes` as mutable
--> src/main.rs:8:13
|
7 | for (_, nodes) in map.iter() {
| ----- help: consider changing this to be a mutable reference: `&mut odes`
8 | nodes.retain(|&n| n == 3);
| ^^^^^ `nodes` is a `&` reference, so the data it refers to cannot be borrowed as mutable
See that it creates a recommendation of using "&mut odes" which assumes I had an &nodes in my source code.
A similar error is seen here (playground) where it chops off the value being iterated over instead of the value being bound to the iterator's Item.
5 | for nodes in vector.iter() {
| ------------- help: consider changing this to be a mutable reference: `&mut ector.iter()`
Removing the #![feature(nll)] causes there to be less suggestion text from the compiler, and thus does not have this bug.