add a comment explaining why two passes are needed

runtime/sema/type.go

@@ -4956,13 +4956,16 @@ func (t *CompositeType) MemberMap() *StringMemberOrderedMap {
 	return t.Members
 }
 
-// TODO: improve naming
 func newCompositeOrInterfaceSupportedEntitlementSet(
 	members *StringMemberOrderedMap,
 	effectiveInterfaceConformanceSet *InterfaceSet,
 ) *EntitlementSet {
 	set := &EntitlementSet{}
 
+	// We need to handle conjunctions and disjunctions separately, in two passes,
+	// as adding entitlements after disjunctions does not remove disjunctions from the set,
+	// whereas adding disjunctions after entitlements does.
+
 	// First pass: Handle maps and conjunctions
 	members.Foreach(func(_ string, member *Member) {
 		switch access := member.Access.(type) {