1:      1  1 CALL pred deep_warning.main/2-0 (det) deep_warning.m:16
mdb> echo on
Command echo enabled.
mdb> register --quiet
mdb> break p
 0: + stop  interface pred deep_warning.p/2-0 (nondet)
mdb> break q
 1: + stop  interface pred deep_sub.q/1-0 (multi)
mdb> continue
       3:      2  2 CALL pred deep_warning.p/2-0 (nondet) deep_warning.m:36 (deep_warning.m:18)
mdb> finish
       5:      3  3 CALL pred deep_sub.q/1-0 (multi) deep_sub.m:12 (deep_warning.m:37)
       7:      3  3 EXIT pred deep_sub.q/1-0 (multi) deep_sub.m:12 (deep_warning.m:37)
       8:      2  2 EXIT pred deep_warning.p/2-0 (nondet) deep_warning.m:36 (deep_warning.m:18)
mdb> dd -d 3 -n 7
Warning: some modules were compiled with a trace level lower than `decl'.
This may result in calls being omitted from the debugging tree.
p(1, 1)
Valid? no
Found incorrect contour:
p(1, 1)
Is this a bug? yes
       8:      2  2 EXIT pred deep_warning.p/2-0 (nondet) deep_warning.m:36 (deep_warning.m:18)
mdb> retry
       3:      2  2 CALL pred deep_warning.p/2-0 (nondet) deep_warning.m:36 (deep_warning.m:18)
mdb> continue
       5:      3  3 CALL pred deep_sub.q/1-0 (multi) deep_sub.m:12 (deep_warning.m:37)
mdb> finish
       7:      3  3 EXIT pred deep_sub.q/1-0 (multi) deep_sub.m:12 (deep_warning.m:37)
mdb> dd -d 3 -n 7
mdb: cannot start declarative debugging, because some event types were
suppressed when this procedure was compiled.
mdb> quit -y