error[E0596]: cannot borrow `y` as mutable, as it is not declared as mutable
  --> $DIR/ex3-both-anon-regions-using-trait-objects.rs:2:3
   |
LL |   y.push(z);
   |   ^ cannot borrow as mutable
   |
help: consider changing this to be mutable
   |
LL | fn foo(x:Box<dyn Fn(&u8, &u8)> , mut y: Vec<&u8>, z: &u8) {
   |                                  +++

error: lifetime may not live long enough
  --> $DIR/ex3-both-anon-regions-using-trait-objects.rs:2:3
   |
LL | fn foo(x:Box<dyn Fn(&u8, &u8)> , y: Vec<&u8>, z: &u8) {
   |                                         -        - let's call the lifetime of this reference `'1`
   |                                         |
   |                                         let's call the lifetime of this reference `'2`
LL |   y.push(z);
   |   ^^^^^^^^^ argument requires that `'1` must outlive `'2`
   |
help: consider introducing a named lifetime parameter
   |
LL | fn foo<'a>(x:Box<dyn Fn(&u8, &u8)> , y: Vec<&'a u8>, z: &'a u8) {
   |       ++++                                   ++          ++

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0596`.