cons x (One y ps) = Zero (cons (x, y) ps)
--
11:21-11:42: Expected <Vec (a, a)> got <Vec a>.
-11:33-11:34: Type (a, a) is not a subtype of a.
-11:36-11:37: Type (a, a) is not a subtype of a.
+11:32-11:38: Expected <a> got <(b, c)>.
11:39-11:41: Expected <Vec a> got <Vec (a, a)>.
\ No newline at end of file