diff --git a/src/smt/theory_seq.cpp b/src/smt/theory_seq.cpp
index cdea02c48..3e1436aa6 100644
--- a/src/smt/theory_seq.cpp
+++ b/src/smt/theory_seq.cpp
@@ -3819,6 +3819,15 @@ void theory_seq::new_eq_eh(dependency* deps, enode* n1, enode* n2) {
         solve_eqs(m_eqs.size()-1);
         enforce_length_coherence(n1, n2);
     }
+    else if (n1 != n2 && m_util.is_re(n1->get_owner())) {
+        warning_msg("equality between regular expressions is not yet supported");
+        eautomaton* a1 = get_automaton(n1->get_owner());
+        eautomaton* a2 = get_automaton(n2->get_owner());
+        // eautomaton* b1 = mk_difference(*a1, *a2);
+        // eautomaton* b2 = mk_difference(*a2, *a1);
+        // eautomaton* c = mk_union(*b1, *b2);
+        // then some emptiness check.
+    }
 }
 
 void theory_seq::new_diseq_eh(theory_var v1, theory_var v2) {