error[E0515]: cannot return value referencing local variable `s` --> $DIR/issue-67765-async-diagnostic.rs:13:5 | LL | let b = &s[..]; | - `s` is borrowed here LL | LL | Err(b)?; | ^^^^^^^ returns a value referencing data owned by the current function error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0515`.