|  | error[E0525]: expected a closure that implements the `Fn` trait, but this closure only implements `FnOnce` | 
|  | --> $DIR/issue-26046-fn-once.rs:4:19 | 
|  | | | 
|  | LL |     let closure = move || { | 
|  | |                   ^^^^^^^ this closure implements `FnOnce`, not `Fn` | 
|  | LL |         vec | 
|  | |         --- closure is `FnOnce` because it moves the variable `vec` out of its environment | 
|  | ... | 
|  | LL |     Box::new(closure) | 
|  | |     ----------------- the requirement to implement `Fn` derives from here | 
|  | | | 
|  | = note: required for the cast from `Box<{closure@$DIR/issue-26046-fn-once.rs:4:19: 4:26}>` to `Box<(dyn Fn() -> Vec<u8> + 'static)>` | 
|  |  | 
|  | error: aborting due to 1 previous error | 
|  |  | 
|  | For more information about this error, try `rustc --explain E0525`. |