Transitive closure virtual table.

internal/util/set.go

@@ -0,0 +1,12 @@
+package util
+
+type Set[E comparable] map[E]struct{}
+
+func (s Set[E]) Add(v E) {
+	s[v] = struct{}{}
+}
+
+func (s Set[E]) Contains(v E) bool {
+	_, ok := s[v]
+	return ok
+}