Uninhabited types in recursive types with "infinite" size

[alecmocatta]

This enum is in theory finitely sized, though it's being detected as infinitely sized.

#![feature(never_type)]
enum Enum<T> {
    A,
    B(Enum<!>, T)
}

(Playground)

error[E0072]: recursive type `Enum` has infinite size
 --> src/lib.rs:2:1
  |
2 | enum Enum<T> {
  | ^^^^^^^^^^^^ recursive type has infinite size
3 |     A,
4 |     B(Enum<!>, T)
  |       ------- recursive without indirection
  |
  = help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Enum` representable