Simplify trigger notifications in equality engine (#4921)

This is further work towards a centralized approach for equality engines.

This PR merges the eqNotifyTriggerEquality callback with the eqNotifyTriggerPredicate callback, and adds assertions that capture the current behavior. It furthermore makes addTriggerEquality private in equality engine and invoked as a special case of addTriggerPredicate. Note this PR does not impact the internal implementation of these methods in equality engine, which indeed is different.

There are two reasons to merge these callbacks:
(1) all theories implement exactly the same method for the two callbacks, whenever they implement both. It would be trivial to do something different (by case splitting on the kind of predicate that is being notified), and moreover it is not recommended they do anything other than immediately propagate the predicate (regardless of whether it is an equality).
(2) It leads to some confusion with eqNotifyTriggerTermEquality, which is invoked when two trigger terms are merged.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/theory/arrays/theory_arrays.cpp b/src/theory/arrays/theory_arrays.cpp
index 51e1b367c..4cc51a87e 100644
--- a/src/theory/arrays/theory_arrays.cpp
+++ b/src/theory/arrays/theory_arrays.cpp
@@ -697,7 +697,7 @@ void TheoryArrays::preRegisterTermInternal(TNode node)
   case kind::EQUAL:
     // Add the trigger for equality
     // NOTE: note that if the equality is true or false already, it might not be added
-    d_equalityEngine->addTriggerEquality(node);
+    d_equalityEngine->addTriggerPredicate(node);
     break;
   case kind::SELECT: {
     // Invariant: array terms should be preregistered before being added to the equality engine