Are Infinite Types (aka Recursive Types) not possible in F#?

Question

I was chatting with Sadek Drobi on twitter when be brought up that F# didn\'t seem to support Infinite Types. It turns out that in C# you can do something along these lines

Answer 1

Recursive record types should work as well.

type A = { A : A }
let rec a : A = { A = a }

I'd be interested in a practical application. Or even an impractical one :)