diff --git a/calendar/base/content/agenda-listbox-utils.js b/calendar/base/content/agenda-listbox-utils.js
index a250c1c831..079e01f930 100644
--- a/calendar/base/content/agenda-listbox-utils.js
+++ b/calendar/base/content/agenda-listbox-utils.js
@@ -558,12 +558,7 @@ agendaListbox.deleteSelectedItem = function(aDoNotConfirm) {
   let listItem = this.agendaListboxControl.selectedItem;
   if (this.isEventListItem(listItem)) {
     let selectedItems = [listItem.occurrence];
-    calendarViewController.deleteOccurrences(
-      selectedItems.length,
-      selectedItems,
-      false,
-      aDoNotConfirm
-    );
+    calendarViewController.deleteOccurrences(selectedItems, false, aDoNotConfirm);
   }
 };
 
diff --git a/calendar/base/content/calendar-clipboard.js b/calendar/base/content/calendar-clipboard.js
index 3591bee2c8..882f356994 100644
--- a/calendar/base/content/calendar-clipboard.js
+++ b/calendar/base/content/calendar-clipboard.js
@@ -122,7 +122,7 @@ function copyToClipboard(aCalendarItemArray = null, aCutMode = false) {
     if (aCutMode) {
       // check for MODIFICATION_PARENT
       let useParent = response == 3;
-      calendarViewController.deleteOccurrences(targetItems.length, targetItems, useParent, true);
+      calendarViewController.deleteOccurrences(targetItems, useParent, true);
     }
   }
 }
diff --git a/calendar/base/content/calendar-management.js b/calendar/base/content/calendar-management.js
index dc454c0f33..03e5ca9727 100644
--- a/calendar/base/content/calendar-management.js
+++ b/calendar/base/content/calendar-management.js
@@ -514,7 +514,7 @@ function calendarListSetupContextMenu(event) {
   }
 
   // Only enable calendar search if there's actually the chance of finding something:
-  let hasProviders = cal.getCalendarSearchService().getProviders({}).length < 1 && "true";
+  let hasProviders = cal.getCalendarSearchService().getProviders().length < 1 && "true";
   setElementValue("list-calendars-context-find", hasProviders, "collapsed");
 }
 
diff --git a/calendar/base/content/calendar-task-tree-utils.js b/calendar/base/content/calendar-task-tree-utils.js
index 415a8a5348..de5a359b65 100644
--- a/calendar/base/content/calendar-task-tree-utils.js
+++ b/calendar/base/content/calendar-task-tree-utils.js
@@ -287,7 +287,7 @@ function modifyTaskFromContext(aEvent, initialDate) {
  */
 function deleteToDoCommand(aEvent, aDoNotConfirm) {
   let tasks = getSelectedTasks(aEvent);
-  calendarViewController.deleteOccurrences(tasks.length, tasks, false, aDoNotConfirm);
+  calendarViewController.deleteOccurrences(tasks, false, aDoNotConfirm);
 }
 
 /**
diff --git a/calendar/base/content/calendar-views-utils.js b/calendar/base/content/calendar-views-utils.js
index abcbf6604b..39a80a44bf 100644
--- a/calendar/base/content/calendar-views-utils.js
+++ b/calendar/base/content/calendar-views-utils.js
@@ -89,13 +89,7 @@ var calendarViewController = {
    * Deletes the given occurrences
    * @see calICalendarViewController
    */
-  deleteOccurrences: function(
-    count,
-    occurrencesArg,
-    useParentItems,
-    doNotConfirm,
-    extResponseArg = null
-  ) {
+  deleteOccurrences: function(occurrencesArg, useParentItems, doNotConfirm, extResponseArg = null) {
     startBatchTransaction();
     let recurringItems = {};
     let extResponse = extResponseArg || { responseMode: Ci.calIItipItem.USER };
@@ -544,7 +538,7 @@ function getLastCalendarView() {
  */
 function deleteSelectedEvents() {
   let selectedItems = currentView().getSelectedItems({});
-  calendarViewController.deleteOccurrences(selectedItems.length, selectedItems, false, false);
+  calendarViewController.deleteOccurrences(selectedItems, false, false);
   // clear selection
   currentView().setSelectedItems(0, [], true);
 }
diff --git a/calendar/base/public/calICalendarSearchProvider.idl b/calendar/base/public/calICalendarSearchProvider.idl
index 96dc36810c..41718398df 100644
--- a/calendar/base/public/calICalendarSearchProvider.idl
+++ b/calendar/base/public/calICalendarSearchProvider.idl
@@ -50,8 +50,7 @@ interface calICalendarSearchService : calICalendarSearchProvider
     /**
      * Gets the currently registered set of search providers.
      */
-    void getProviders(out uint32_t aCount,
-                      [array, size_is(aCount), retval] out calICalendarSearchProvider aProviders);
+    Array<calICalendarSearchProvider> getProviders();
 
     /**
      * Adds a new search provider.
diff --git a/calendar/base/public/calICalendarViewController.idl b/calendar/base/public/calICalendarViewController.idl
index caadb8569f..dff5820434 100644
--- a/calendar/base/public/calICalendarViewController.idl
+++ b/calendar/base/public/calICalendarViewController.idl
@@ -63,8 +63,7 @@ interface calICalendarViewController : nsISupports
    * @param aDoNotConfirm   If set, the events will be deleted without
    *                        confirmation.
    */
-  void deleteOccurrences (in uint32_t aCount,
-                          [array, size_is(aCount)] in calIItemBase aOccurrences,
+  void deleteOccurrences (in Array<calIItemBase> aOccurrences,
                           in boolean aUseParentItems,
                           in boolean aDoNotConfirm);
 };
diff --git a/calendar/base/src/calCalendarSearchService.js b/calendar/base/src/calCalendarSearchService.js
index 5672b26eec..057b3a72d6 100644
--- a/calendar/base/src/calCalendarSearchService.js
+++ b/calendar/base/src/calCalendarSearchService.js
@@ -83,8 +83,7 @@ calCalendarSearchService.prototype = {
   },
 
   // calICalendarSearchService:
-  getProviders: function(out_aCount) {
-    out_aCount.value = this.mProviders.size;
+  getProviders: function() {
     return [...this.mProviders];
   },
   addProvider: function(aProvider) {
diff --git a/calendar/test/unit/test_search_service.js b/calendar/test/unit/test_search_service.js
index d14136e379..81fab725ca 100644
--- a/calendar/test/unit/test_search_service.js
+++ b/calendar/test/unit/test_search_service.js
@@ -14,9 +14,9 @@ function run_test() {
 }
 
 function test_found() {
-  search.getProviders({}).forEach(search.removeProvider, search);
+  search.getProviders().forEach(search.removeProvider, search);
 
-  equal(search.getProviders({}).length, 0);
+  equal(search.getProviders().length, 0);
 
   let provider1 = {
     id: 1,
@@ -42,12 +42,12 @@ function test_found() {
   provider2.wrappedJSObject = provider2;
 
   search.addProvider(provider1);
-  equal(search.getProviders({}).length, 1);
+  equal(search.getProviders().length, 1);
   search.addProvider(provider2);
-  equal(search.getProviders({}).length, 2);
+  equal(search.getProviders().length, 2);
   search.removeProvider(provider1);
-  equal(search.getProviders({}).length, 1);
-  equal(search.getProviders({})[0].wrappedJSObject.id, 2);
+  equal(search.getProviders().length, 1);
+  equal(search.getProviders()[0].wrappedJSObject.id, 2);
 
   let listener = {
     called: false,
@@ -66,7 +66,7 @@ function test_found() {
 }
 
 function test_failure() {
-  search.getProviders({}).forEach(search.removeProvider, search);
+  search.getProviders().forEach(search.removeProvider, search);
 
   let provider = {
     searchForCalendars: function(aStr, aHint, aMax, aListener) {
@@ -90,7 +90,7 @@ function test_failure() {
 }
 
 function test_cancel() {
-  search.getProviders({}).forEach(search.removeProvider, search);
+  search.getProviders().forEach(search.removeProvider, search);
 
   let provider = {
     QueryInterface: cal.generateQI([Ci.calICalendarSearchProvider, Ci.calIOperation]),