[gecode-users] Access to the last propagator invoked in case of ES_FAILED

[David Rijsman]

But one could enumerate the reasons. I mean being in a search one
could conclude that the reason of a failure is due to the branching in
case one has no propagator and because of the propagator if one has
one. Being outside the search one can conclude the same but the reason
is not the branching but the posting of the constraint in case of a
failure without a last propagator.