ref: 77a37e3330f03b9f1a9c45810994d94c921b45ae
dir: /test/occur.myr/
use std /* 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 }