| ---------- required by `Visit::visit`
...
LL | <() as Visit>::visit();
- | ^^^^^^^^^^^^^^^^^^^^ expected (), found &()
+ | ^^^^^^^^^^^^^^^^^^^^ expected `()`, found `&()`
|
- = note: expected type `()`
- found type `&()`
= note: required because of the requirements on the impl of `Visit` for `()`
error: aborting due to previous error