UMLR — Section: 15.3.12, p 588, 589

There are 3 kinds (TransitionKind) of transitions: internal, external and local. Are there firing priorities between these? For example, consider the case of an internal transition within a state and an external transition with same state as its source state, triggered by the same event, with no guard conditions. If that event occurs, which transition(s) will fire? The standard states, "An internal transition in a state conflicts only with transitions that cause an exit from that state," but neither the firing priorities nor the transition selection algorithm define how such a conflict should be resolved.