error[E0621]: explicit lifetime required in the type of `x`
  --> $DIR/ex1-return-one-existing-name-if-else-using-impl-3.rs:18:36
   |
16 |   fn foo<'a>(&'a self, x: &i32) -> &i32 {
   |                        - consider changing the type of `x` to `&'a i32`
17 | 
18 |     if true { &self.field } else { x }
   |                                    ^ lifetime `'a` required

error: aborting due to previous error(s)