Cannot return value that references local variable
Local variables, function parameters and temporaries are all dropped before the
end of the function body. So a reference to them cannot be returned.
Erroneous code example:
```compile_fail,E0515
fn get_dangling_reference() -> &'static i32 {
let x = 0;
&x
}
```
```compile_fail,E0515
use std::slice::Iter;
fn get_dangling_iterator<'a>() -> Iter<'a, i32> {
let v = vec![1, 2, 3];
v.iter()
}
```
Consider returning an owned value instead:
```
use std::vec::IntoIter;
fn get_integer() -> i32 {
let x = 0;
x
}
fn get_owned_iterator() -> IntoIter<i32> {
let v = vec![1, 2, 3];
v.into_iter()
}
```