Used type abbreviation in BFF example.

examples/bff_paper_example.c

@@ -39,6 +39,8 @@ typedef u64 pte_t;
 //@  pte_leaf_attr_hi: integer[51..63]
 //@rc::end
 
+//@rc::typedef pte_t ≔ bitfield<Pte>
+
 #define PTE_TYPE_BLOCK 0
 #define PTE_TYPE_PAGE  1
 #define PTE_TYPE_TABLE 1
@@ -55,7 +57,7 @@ typedef u64 pte_t;
 //@rc::end
 
 [[rc::parameters("pte : Pte")]]
-[[rc::args("pte @ bitfield<Pte>")]]
+[[rc::args("pte @ pte_t")]]
 [[rc::requires("{bitfield_wf pte}")]] // FIXME not necessary.
 [[rc::returns("{pte_valid pte} @ boolean<bool_it>")]]
 static bool pte_valid(pte_t pte) {
@@ -78,7 +80,7 @@ static bool pte_valid(pte_t pte) {
 
 [[rc::requires("{bitfield_wf old}", "{bitfield_wf pa}", "{bitfield_wf attr}")]] // FIXME not necessary.
 [[rc::parameters("p : loc", "old : Pte", "pa : Pte", "attr : Pte", "level : Z")]]
-[[rc::args("p @ &own<old @ bitfield<Pte>>", "pa @ bitfield<Pte>", "attr @ bitfield<Pte>", "level @ int<u32>")]]
+[[rc::args("p @ &own<old @ pte_t>", "pa @ pte_t", "attr @ pte_t", "level @ int<u32>")]]
 [[rc::requires("{old.(pte_valid) = false}")]]
 [[rc::returns("{true} @ boolean<bool_it>")]]
 [[rc::ensures("own p : {svl_pte pa level attr} @ bitfield<Pte>")]]