error[E0308]: mismatched types
  --> $DIR/ex2b-push-no-existing-names.rs:16:12
   |
16 |     x.push(y);
   |            ^ lifetime mismatch
   |
   = note: expected type `Ref<'_, _>`
              found type `Ref<'_, _>`
note: the anonymous lifetime #3 defined on the body at 15:43...
  --> $DIR/ex2b-push-no-existing-names.rs:15:44
   |
15 |   fn foo(x: &mut Vec<Ref<i32>>, y: Ref<i32>) {
   |  ____________________________________________^ starting here...
16 | |     x.push(y);
17 | | }
   | |_^ ...ending here
note: ...does not necessarily outlive the anonymous lifetime #2 defined on the body at 15:43
  --> $DIR/ex2b-push-no-existing-names.rs:15:44
   |
15 |   fn foo(x: &mut Vec<Ref<i32>>, y: Ref<i32>) {
   |  ____________________________________________^ starting here...
16 | |     x.push(y);
17 | | }
   | |_^ ...ending here

error: aborting due to previous error