(type u32 (primitive u32))
(type A (enum (A1 (x u32))))

(decl Ext1 (u32) A)
(decl Ext2 (u32) A)
(extractor Ext1 ext1)
(extractor Ext2 ext2)

(decl Lower (A) A)

(rule
  (Lower
    (and
      a
      (Ext1 x)
      (Ext2 =x)))
  a)