1 error[E0597]: `books` does not live long enough
2 --> $DIR/borrowck-escaping-closure-error-2.rs:21:14
4 LL | Box::new(|| books.push(4))
5 | ^^^^^^^^^^^^^^^^ borrowed value does not live long enough
8 | - `books` dropped here while still borrowed
10 note: borrowed value must be valid for the lifetime 'a as defined on the function body at 19:8...
11 --> $DIR/borrowck-escaping-closure-error-2.rs:19:8
13 LL | fn foo<'a>(x: &'a i32) -> Box<FnMut()+'a> {
16 error: aborting due to previous error
18 For more information about this error, try `rustc --explain E0597`.