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@qguv
Created Dec 11, 2021
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// extended from example at:
// https://willmurphyscode.net/2018/04/25/fixing-a-simple-lifetime-error-in-rust/
pub struct SomeCollection<'a> {
strings: Vec<&'a str>,
}
impl<'a> SomeCollection<'a> {
pub fn new() -> Self {
SomeCollection {
strings: Vec::new(),
}
}
pub fn insert(&mut self, s: &'a str) {
self.strings.push(s);
}
// an attempt to avoid the borrow error, see below
pub fn insert_push(&mut self, v: &'a mut Vec<String>, value: String) {
// store in vector
v.push(value);
// get reference to just-stored item
let vp = v.last().unwrap();
// store reference in collection
self.insert(vp);
}
// another attempt at avoiding the borrow error, see below
pub fn insert_last(&mut self, v: &'a Vec<String>) {
self.strings.push(v.last().unwrap());
}
}
#[cfg(test)]
mod tests {
use super::SomeCollection;
#[test]
fn test() {
let mut storage = Vec::new();
let mut my_collection = SomeCollection::new();
(0..10).for_each(|item| {
let value = format!("value number {}", item + 1);
// error: borrow of moved value (rust doesn't update the reference, sure, understandable)
//storage.push(value);
//my_collection.insert(&value);
// error: borrowed data escapes outside of closure
storage.push(value);
my_collection.insert(storage.last().unwrap());
// error: borrowed data escapes outside of closure
//storage.push(value);
//my_collection.insert_last(&storage);
// error: borrowed data escapes outside of closure
//my_collection.insert_push(&mut storage, value);
});
}
}
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