error[E0623]: lifetime mismatch
  --> $DIR/ex3-both-anon-regions-using-impl-items.rs:6:16
   |
LL |     fn foo(x: &mut Vec<&u8>, y: &u8) {
   |                        ---      --- these two types are declared with different lifetimes...
LL |         x.push(y);
   |                ^ ...but data from `y` flows into `x` here
   |
   = note: each elided lifetime in input position becomes a distinct lifetime
help: consider introducing a named lifetime parameter and update trait if needed
   |
LL |     fn foo<'a>(x: &mut Vec<&'a u8>, y: &'a u8) {
   |           ++++              ++          ++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0623`.