The following code won't compile:
fn test<'a>(index: usize, v: &'a mut Vec<i32>) -> Option<&'a i32> {
{
let t = v.get(index);
if t.is_some() {
return t
}
//return t
}
v.insert(index, index as i32 + 1);
v.get(index)
}
error[E0502]: cannot borrow `*v` as mutable because it is also borrowed as immutable
--> src/main.rs:9:5
|
3 | let t = v.get(index);
| - immutable borrow occurs here
...
9 | v.insert(index, index as i32 + 1);
| ^ mutable borrow occurs here
10 | v.get(index)
11 | }
| - immutable borrow ends here
I thought this code would be fine because the immutable borrow occurs in an inner block. What's weird is that if I remove the if-clause and just return "t" in the inner block then the code compiles fine.
Am I missing something here? I am using Rust 1.22.1 on Linux.
