(intersects (values-types-equal-or-intersect old-atype atype))
(new-atype (values-type-intersection old-atype atype))
(new-ctype (values-type-intersection
(intersects (values-types-equal-or-intersect old-atype atype))
(new-atype (values-type-intersection old-atype atype))
(new-ctype (values-type-intersection