error: unsatisfied lifetime constraints
  --> $DIR/issue-40510-3.rs:18:9
   |
LL |       || {
   |       --
   |       ||
   |       |return type of closure is [closure@$DIR/issue-40510-3.rs:18:9: 20:10 x:&'2 mut std::vec::Vec<()>]
   |       lifetime `'1` represents this closure's body
LL | /         || {
LL | |             x.push(())
LL | |         }
   | |_________^ returning this value requires that `'1` must outlive `'2`
   |
   = note: closure implements `FnMut`, so references to captured variables can't escape the closure

error: aborting due to previous error