E0623 gives wrong error message for following example with fn items

[gaurikholkar-zz]

fn foo(x:  fn(&u8, &u8), y: Vec<&u8>, z: &u8) {
  y.push(z); 
}

fn main(){}

gives

2 | fn foo(x:  fn(&u8, &u8), y: Vec<&u8>, z: &u8) {
  |               ---  --- these references are not declared with the same lifetime...
3 |   y.push(z);
  |          ^ ...but data from `z` flows into `y` here

but should be giving

2 | fn foo(x:  fn(&u8, &u8), y: Vec<&u8>, z: &u8) {
  |                                 ---      --- these references are not declared with the same lifetime...
3 |   y.push(z); // index will be zero or one
  |          ^ ...but data from `z` flows into `y` here

cc @nikomatsakis

[nikomatsakis]

There is a similar problem around trait objects:

fn foo(x: Box<Fn(&u8, &u8)>, y: Vec<&u8>, z: &u8) {
  y.push(z); 
}

fn main(){}

Which currently gives:

error[E0623]: lifetime mismatch
 --> src/main.rs:2:10
  |
1 | fn foo(x: Box<Fn(&u8, &u8)>, y: Vec<&u8>, z: &u8) {
  |                  ---  --- these references are not declared with the same lifetime...
2 |   y.push(z); 
  |          ^ ...but data from `z` flows into `y` here

but it should be highlighting the regions in y and z.

[gaurikholkar-zz]

Fixed in #44516. @nikomatsakis, hence closing