E1:     C1 CALL pred catch.main/2-0 (cc_multi) catch.m:16
mdb> echo on
Command echo enabled.
mdb> register --quiet
mdb> break p
 0: + stop  interface pred catch.p/2-0 (cc_multi)
mdb> continue
      E2:     C2 CALL pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:17)
mdb> finish
      E3:     C2 EXIT pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:17)
mdb> dd -d 3 -n 7
p(1, exception(univ_cons("q: bad input")))
Valid? no
Call q(1, _)
Throws "q: bad input"
Expected? no
Found unhandled or incorrect exception:
q(1, _)
"q: bad input"
Is this a bug? yes
      E4:     C3 EXCP pred catch.q/2-0 (det) e;c3; catch.m:33 (exception.m:NNNN)
mdb> continue
      E3:     C2 EXIT pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:17)
mdb> continue
exception(univ_cons("q: bad input"))
      E5:     C4 CALL pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:19)
mdb> finish
      E6:     C4 EXIT pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:19)
mdb> dd -d 3 -n 7
p(2, succeeded(2))
Valid? no
q(2, 2)
Valid? yes
Found incorrect contour:
try(q(2), succeeded(2))
p(2, succeeded(2))
Is this a bug? yes
      E6:     C4 EXIT pred catch.p/2-0 (cc_multi) catch.m:24 (catch.m:19)
mdb> continue
succeeded(2)