automock fails for method taking Option<&u32>

[qwandor]

Trying to mock the following trait fails:

#[mockall::automock]
trait Foo {
    fn bar(&self, x: Option<&u32>);
}

with a confusing error message:

error[E0106]: missing lifetime specifier
 --> src/main.rs:3:29
  |
3 |     fn bar(&self, x: Option<&u32>);
  |                             ^ expected named lifetime parameter
  |
  = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'a` lifetime
  |
1 ~ for<'a> #[mockall::automock]
2 | trait Foo {
3 ~     fn bar(&self, x: Option<&'a u32>);
  |
help: consider introducing a named lifetime parameter
  |
1 ~ #[mockall::automock]<'a>
2 | trait Foo {
3 ~     fn bar(&self, x: Option<&'a u32>);
  |

error[E0637]: `&` without an explicit lifetime name cannot be used here
 --> src/main.rs:3:29
  |
3 |     fn bar(&self, x: Option<&u32>);
  |                             ^ explicit lifetime name needed here
  |
help: consider introducing a higher-ranked lifetime here
  |
1 ~ for<'a> #[mockall::automock]
2 | trait Foo {
3 ~     fn bar(&self, x: Option<&'a u32>);
  |

Some errors have detailed explanations: E0106, E0637.
For more information about an error, try `rustc --explain E0106`.

If there is some reason this can't be supported, the error message should at least be more helpful in explaining why.

[asomers]

Have you tried adding a lifetime parameter, like this?

fn bar<'a>(&'a self, x: Option<&'a u32>);