ref: 4ef66b11ded8bc99387219a81328d33c775ce7a9
dir: /test/occur.myr/
/* checks that f is not an infinite type (ie, the type
doesn't exist within itself). If 'f' typechecked,
it's type would be:
f : (-> (-> (-> ... ad infinitum ...)))
*/
const f = {
-> f
}