Reference’s lifetime of borrowed content doesn’t match the expected lifetime.
Erroneous code example:
pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'static str {
if maybestr.is_none() {
"(none)"
} else {
let s: &'a str = maybestr.as_ref().unwrap();
s // Invalid lifetime!
}
}To fix this error, either lessen the expected lifetime or find a way to not have to use this reference outside of its current scope (by running the code directly in the same block for example?):
// In this case, we can fix the issue by switching from "static" lifetime to 'a
pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'a str {
if maybestr.is_none() {
"(none)"
} else {
let s: &'a str = maybestr.as_ref().unwrap();
s // Ok!
}
}