"Lifetime in struct : "this value requires that `'1` must outlive `'static` - rust

Question

I am new to the concept of lifetime but I don't understand why the current code gives me an error
error ->
[1]: https://i.stack.imgur.com/v4Yf6.png
Code :
pub struct Folder<'a> {
pub name: &'a str,
pub contents: Vec<Box<dyn Executable>>,
pub parent: Box<Option<&'a Folder<'a>>>
}
impl<'a> Folder<'a> {
pub fn new(folder_name: &'a str, json_content: &'a Value) -> Self {
Self {
name: folder_name,
contents: Folder::get_content(json_content),
parent: Box::new(None)
}
}
fn get_content(json_content: &Value) -> Vec<Box<dyn Executable>> {
let elements_in_folder: &Vec<Value> = json_content.as_array().unwrap();
let mut contents: Vec<Box<dyn Executable>> = Vec::new();
for element in elements_in_folder.iter() {
match element["type"].as_str().unwrap() {
"folder" => {
let folder = Folder::new(
element["name"].as_str().unwrap(),
&element["content"],
);
contents.push(Box::new(folder))
}
"command" => contents.push(Box::new(Command::new(&element))),
"combo" => contents.push(Box::new(Combo::new(&element))),
_ => panic!("Folder: field type unknow"),
}
}
contents // THE ERROR IS HERE
}
}
Folder Command and Combo impl Executable

Answer 1

Your contents is borrowing values from inside the argument. You need to make that explicit, with a lifetime constraint.
fn get_content<'a>(json_content: &'a Value) -> Vec<Box<dyn Executable + 'a>> {
...
}
or, equivalently, you can use the anonymous lifetime. The following is equivalent to the above but shorter.
fn get_content(json_content: &Value) -> Vec<Box<dyn Executable + '_>> {
...
}