diff --git a/lib/src/model/date/date_range_item.dart b/lib/src/model/date/date_range_item.dart
index bb946446..e7cd8ddf 100644
--- a/lib/src/model/date/date_range_item.dart
+++ b/lib/src/model/date/date_range_item.dart
@@ -58,12 +58,13 @@ class DateRangeItem extends Item with DateRanger {
 
   @override
   bool operator ==(Object other) =>
+      super == other &&
       other is DateRangeItem &&
       startDate == other.startDate &&
       endDate == other.endDate;
 
   @override
-  int get hashCode => Object.hash(startDate, endDate);
+  int get hashCode => Object.hash(super.hashCode, startDate, endDate);
 
   @override
   int compareTo(covariant DateRangeItem other) =>
diff --git a/lib/src/model/date/holiday.dart b/lib/src/model/date/holiday.dart
index 55884e1d..6d417ce9 100644
--- a/lib/src/model/date/holiday.dart
+++ b/lib/src/model/date/holiday.dart
@@ -23,6 +23,13 @@ class Holiday extends DateRangeItem {
         ...super.toJson(),
         _JsonFields.kind: kind.index,
       };
+
+  @override
+  bool operator ==(Object other) =>
+      super == other && other is Holiday && kind == other.kind;
+
+  @override
+  int get hashCode => Object.hash(super.hashCode, kind.hashCode);
 }
 
 enum HolidayKind { festivity, freeDisposal }