Index: src/memorycalendar.cpp
===================================================================
--- src/memorycalendar.cpp
+++ src/memorycalendar.cpp
@@ -111,7 +111,7 @@
      * but i merged them into one (indexed by type) because it simplifies code using
      * it. No need to if else based on type.
      */
-    QMap<IncidenceBase::IncidenceType, QMultiHash<QString, IncidenceBase::Ptr> > mIncidencesForDate;
+    QMap<IncidenceBase::IncidenceType, QMultiHash<QDate, IncidenceBase::Ptr> > mIncidencesForDate;
 
     void insertIncidence(const Incidence::Ptr &incidence);
 
@@ -186,7 +186,7 @@
 
         const QDateTime dt = incidence->dateTime(Incidence::RoleCalendarHashing);
         if (dt.isValid()) {
-            d->mIncidencesForDate[type].remove(dt.date().toString(), incidence);
+            d->mIncidencesForDate[type].remove(dt.date(), incidence);
         }
         // Delete child-incidences.
         if (!incidence->hasRecurrenceId()) {
@@ -286,7 +286,7 @@
         mIncidencesByIdentifier.insert(incidence->instanceIdentifier(), incidence);
         const QDateTime dt = incidence->dateTime(Incidence::RoleCalendarHashing);
         if (dt.isValid()) {
-            mIncidencesForDate[type].insert(dt.date().toString(), incidence);
+            mIncidencesForDate[type].insert(dt.date(), incidence);
         }
 
     } else {
@@ -418,10 +418,8 @@
     Todo::List todoList;
     Todo::Ptr t;
 
-    const QString dateStr = date.toString();
-    QMultiHash<QString, IncidenceBase::Ptr >::const_iterator it =
-        d->mIncidencesForDate[Incidence::TypeTodo].constFind(dateStr);
-    while (it != d->mIncidencesForDate[Incidence::TypeTodo].constEnd() && it.key() == dateStr) {
+    auto it = d->mIncidencesForDate[Incidence::TypeTodo].constFind(date);
+    while (it != d->mIncidencesForDate[Incidence::TypeTodo].constEnd() && it.key() == date) {
         t = it.value().staticCast<Todo>();
         todoList.append(t);
         ++it;
@@ -554,8 +552,7 @@
 
         const QDateTime dt = inc->dateTime(Incidence::RoleCalendarHashing);
         if (dt.isValid()) {
-            const Incidence::IncidenceType type = inc->type();
-            d->mIncidencesForDate[type].remove(dt.date().toString(), inc);
+            d->mIncidencesForDate[inc->type()].remove(dt.date(), inc);
         }
     }
 }
@@ -583,8 +580,7 @@
 
         const QDateTime dt = inc->dateTime(Incidence::RoleCalendarHashing);
         if (dt.isValid()) {
-            const Incidence::IncidenceType type = inc->type();
-            d->mIncidencesForDate[type].insert(dt.date().toString(), inc);
+            d->mIncidencesForDate[inc->type()].insert(dt.date(), inc);
         }
 
         notifyIncidenceChanged(inc);
@@ -608,12 +604,11 @@
     Event::Ptr ev;
 
     // Find the hash for the specified date
-    const QString dateStr = date.toString();
-    QMultiHash<QString, IncidenceBase::Ptr >::const_iterator it =
-        d->mIncidencesForDate[Incidence::TypeEvent].constFind(dateStr);
+    const auto &eventsForDate = d->mIncidencesForDate[Incidence::TypeEvent];
+    auto it = eventsForDate.constFind(date);
     // Iterate over all non-recurring, single-day events that start on this date
     const auto ts = timeZone.isValid() ? timeZone : this->timeZone();
-    while (it != d->mIncidencesForDate[Incidence::TypeEvent].constEnd() && it.key() == dateStr) {
+    while (it != eventsForDate.constEnd() && it.key() == date) {
         ev = it.value().staticCast<Event>();
         QDateTime end(ev->dtEnd().toTimeZone(ev->dtStart().timeZone()));
         if (ev->allDay()) {
@@ -846,11 +841,8 @@
     Journal::List journalList;
     Journal::Ptr j;
 
-    QString dateStr = date.toString();
-    QMultiHash<QString, IncidenceBase::Ptr >::const_iterator it =
-        d->mIncidencesForDate[Incidence::TypeJournal].constFind(dateStr);
-
-    while (it != d->mIncidencesForDate[Incidence::TypeJournal].constEnd() && it.key() == dateStr) {
+    auto it = d->mIncidencesForDate[Incidence::TypeJournal].constFind(date);
+    while (it != d->mIncidencesForDate[Incidence::TypeJournal].constEnd() && it.key() == date) {
         j = it.value().staticCast<Journal>();
         journalList.append(j);
         ++it;