error[E0716]: temporary value dropped while borrowed
  --> $DIR/issue-30438-a.rs:22:17
   |
LL |         return &Test { s: &self.s};
   |                 ^^^^^^^^^^^^^^^^^^- temporary value is freed at the end of this statement
   |                 |
   |                 creates a temporary which is freed while still in use
   |
note: borrowed value must be valid for the anonymous lifetime #1 defined on the method body at 21:5...
  --> $DIR/issue-30438-a.rs:21:5
   |
LL | /     fn index(&self, _: usize) -> &Self::Output {
LL | |         return &Test { s: &self.s};
LL | |         //~^ ERROR: borrowed value does not live long enough
LL | |     }
   | |_____^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0716`.