E1:     C1 CALL pred dice.main/2-0 (det) dice.m:20
mdb> mdb> Contexts will not be printed.
mdb> echo on
Command echo enabled.
mdb> trust library_forwarding
Trusting module library_forwarding
mdb> break dice.merge_sort
 0: + stop  interface pred dice.merge_sort/2-0 (det)
mdb> continue
      E2:     C2 CALL pred dice.merge_sort/2-0 (det)
mdb> delete *
 0: E stop  interface pred dice.merge_sort/2-0 (det)
mdb> finish
      E3:     C2 EXIT pred dice.merge_sort/2-0 (det)
mdb> format pretty
mdb> format_param depth 10
mdb> dd -s sdq -f dice.fail -p dice.pass
merge_sort([4, 1, 2, 3], [1, 1, 2, 3])
Valid? n
merge([4], [1], [1, 1])
Valid? n
merge([], [1], [1])
Valid? y
Found incorrect contour:
merge([], [1], [1])
merge([4], [1], [1, 1])
Is this a bug? y
      E4:     C3 EXIT pred dice.merge/3-0 (det)
mdb> quit -y