error[E0532]: expected tuple struct or tuple variant, found unit variant `FarmAnimal::Cow`
  --> $DIR/issue-84700.rs:15:9
   |
LL |     Cow,
   |     --- `FarmAnimal::Cow` defined here
...
LL |         FarmAnimal::Cow(_) => "moo".to_string(),
   |         ^^^^^^^^^^^^^^^^^^ help: use this syntax instead: `FarmAnimal::Cow`

error[E0164]: expected tuple struct or tuple variant, found struct variant `FarmAnimal::Chicken`
  --> $DIR/issue-84700.rs:17:9
   |
LL |         FarmAnimal::Chicken(_) => "cluck, cluck!".to_string(),
   |         ^^^^^^^^^^^^^^^^^^^^^^ not a tuple struct or tuple variant

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0164, E0532.
For more information about an error, try `rustc --explain E0164`.