ref: ae076c5f98e0dda484f92ac400b5657f5924efb5
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
}