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

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

(decl C (bool) A)
(extern constructor C c)

(decl Lower (A) A)

(rule
  (Lower
    (and
      a
      (Ext1 x)
      (Ext2 =q)))
  (C y))

(type R (enum (A (x u32))))

(type Opcode (enum A B C))
(type MachInst (enum D E F))
(decl Lower2 (Opcode) MachInst)
(rule
  (Lower2 (Opcode.A))
  (R.A (Opcode.A)))
(rule
  (Lower2 (Opcode.B))
  (MachInst.E))
(rule
  (Lower2 (Opcode.C))
  (MachInst.F))