E0515 — Cannot Return Reference to Local Variable

Co powoduje ten błąd

The local variable will be dropped when the function returns, so a reference to it would be dangling. Rust prevents returning references to data that does not outlive the function call.

Jak to naprawić

Return an owned value (String, Vec, Box) instead of a reference. Move the data to a longer-lived scope. Use a static reference if the data is a compile-time constant.

fn foo() -> &str {
  let s = String::from("hi");
  &s
}