diff --git a/mail/base/content/ABSearchDialog.js b/mail/base/content/ABSearchDialog.js
index c49e21e37a..a13c1f1f05 100644
--- a/mail/base/content/ABSearchDialog.js
+++ b/mail/base/content/ABSearchDialog.js
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 Components.utils.import("resource:///modules/ABQueryUtils.jsm");
+Components.utils.import("resource:///modules/iteratorUtils.js");
 Components.utils.import("resource:///modules/mailServices.js");
 Components.utils.import("resource://gre/modules/PluralForm.jsm");
 Components.utils.import("resource://gre/modules/Services.jsm");
@@ -178,11 +179,7 @@ function onSearch()
 
     var searchUri = currentAbURI + "?(";
 
-    var count = gSearchSession.searchTerms.Count();
-
-    for (var i=0; i<count; i++) {
-      var searchTerm = gSearchSession.searchTerms.GetElementAt(i).QueryInterface(nsIMsgSearchTerm);
-
+    for (let searchTerm of fixIterator(gSearchSession.searchTerms, nsIMsgSearchTerm)) {
       // get the "and" / "or" value from the first term
       if (i == 0) {
        if (searchTerm.booleanAnd)
diff --git a/mail/base/modules/searchSpec.js b/mail/base/modules/searchSpec.js
index d9cc892c84..7ce873113d 100644
--- a/mail/base/modules/searchSpec.js
+++ b/mail/base/modules/searchSpec.js
@@ -361,7 +361,7 @@ SearchSpec.prototype = {
     let session = this.session;
 
     // clear out our current terms and scope
-    session.searchTerms.QueryInterface(Ci.nsISupportsArray).Clear();
+    session.searchTerms.clear();
     session.clearScopes();
 
     // the scope logic needs to know if any terms look at the body attribute.
diff --git a/mailnews/base/search/content/FilterEditor.js b/mailnews/base/search/content/FilterEditor.js
index 986185d349..757ac067c8 100644
--- a/mailnews/base/search/content/FilterEditor.js
+++ b/mailnews/base/search/content/FilterEditor.js
@@ -137,9 +137,9 @@ function filterEditorOnLoad()
         }
 
         // copy the search terms
-        for (let i = 0; i < copiedFilter.searchTerms.Count(); i++)
+        for (let i = 0; i < copiedFilter.searchTerms.length; i++)
         {
-          var searchTerm = copiedFilter.searchTerms.QueryElementAt(i,
+          let searchTerm = copiedFilter.searchTerms.queryElementAt(i,
             Components.interfaces.nsIMsgSearchTerm);
 
           var newTerm = newFilter.createTerm();
diff --git a/mailnews/base/search/content/searchTermOverlay.js b/mailnews/base/search/content/searchTermOverlay.js
index 3068065eb4..78f061f397 100644
--- a/mailnews/base/search/content/searchTermOverlay.js
+++ b/mailnews/base/search/content/searchTermOverlay.js
@@ -173,8 +173,8 @@ function initializeBooleanWidgets()
 
 function initializeSearchRows(scope, searchTerms)
 {
-    for (var i = 0; i < searchTerms.Count(); i++) {
-        var searchTerm = searchTerms.QueryElementAt(i, nsIMsgSearchTerm);
+    for (let i = 0; i < searchTerms.length; i++) {
+        let searchTerm = searchTerms.queryElementAt(i, nsIMsgSearchTerm);
         createSearchRow(i, scope, searchTerm, false);
         gTotalSearchTerms++;
     }
@@ -470,19 +470,19 @@ function removeSearchRow(index)
 
 
     if (searchTermObj.searchTerm) {
-        gSearchRemovedTerms[gSearchRemovedTerms.length] = searchTermObj.searchTerm;
+        gSearchRemovedTerms.push(searchTermObj.searchTerm);
     } else {
         //dump("That wasn't real. ignoring \n");
     }
 
     listitem.remove();
-    
+
     // now remove the item from our list of terms
     gSearchTerms.splice(index, 1); 
 }
 
 // save the search terms from the UI back to the actual search terms
-// searchTerms: nsISupportsArray of terms
+// searchTerms: nsIMutableArray of terms
 // termOwner:   object which can contain and create the terms
 //              (will be unnecessary if we just make terms creatable
 //               via XPCOM)
@@ -491,7 +491,7 @@ function saveSearchTerms(searchTerms, termOwner)
     var matchAll = gSearchBooleanRadiogroup.value == 'matchAll';
     var i;
     for (i = 0; i < gSearchRemovedTerms.length; i++)
-        searchTerms.RemoveElement(gSearchRemovedTerms[i]);
+        searchTerms.removeElementAt(searchTerms.indexOf(0, gSearchRemovedTerms[i]));
 
     for (i = 0; i<gSearchTerms.length; i++) {
         try {
@@ -510,7 +510,7 @@ function saveSearchTerms(searchTerms, termOwner)
                 // but we need to make the array longer anyway
                 termOwner.appendTerm(searchTerm);
             }
-            searchTerms.SetElementAt(i, searchTerm);
+            searchTerms.replaceElementAt(searchTerm, i, /* weak */ false);
         } catch (ex) {
             dump("** Error saving element " + i + ": " + ex + "\n");
         }
diff --git a/mailnews/base/search/public/nsIMsgFilter.idl b/mailnews/base/search/public/nsIMsgFilter.idl
index 5571b2f9a9..8780761c6c 100644
--- a/mailnews/base/search/public/nsIMsgFilter.idl
+++ b/mailnews/base/search/public/nsIMsgFilter.idl
@@ -6,18 +6,9 @@
 
 #include "nsISupports.idl"
 #include "nsMsgFilterCore.idl"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-%{C++
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-%}
-interface nsISupportsArray;
 
 interface nsIArray;
+interface nsIMutableArray;
 interface nsIOutputStream;
 interface nsIMsgFilterCustomAction;
 interface nsIMsgFilterList;
@@ -87,7 +78,7 @@ interface nsIMsgFilter : nsISupports {
 
     nsIMsgSearchTerm createTerm();
 
-    attribute nsISupportsArray searchTerms;
+    attribute nsIMutableArray searchTerms;
 
     attribute nsIMsgSearchScopeTerm scope;
 
diff --git a/mailnews/base/search/public/nsIMsgSearchSession.idl b/mailnews/base/search/public/nsIMsgSearchSession.idl
index 36ed7409ef..9c43846d1f 100644
--- a/mailnews/base/search/public/nsIMsgSearchSession.idl
+++ b/mailnews/base/search/public/nsIMsgSearchSession.idl
@@ -6,21 +6,12 @@
 #include "nsISupports.idl"
 #include "nsIMsgSearchValue.idl"
 
+interface nsIMutableArray;
 interface nsIMsgSearchAdapter;
 interface nsIMsgSearchTerm;
 interface nsIMsgSearchNotify;
 interface nsIMsgHdr;
 interface nsIMsgDatabase;
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-%{C++
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-%}
-interface nsISupportsArray;
 interface nsIMsgWindow;
 
 //////////////////////////////////////////////////////////////////////////////
@@ -50,9 +41,9 @@ interface nsIMsgSearchSession :  nsISupports {
                      in boolean BooleanAND,
                      in string customString);
 
-  readonly attribute nsISupportsArray searchTerms;
+  attribute nsIMutableArray searchTerms;
 
-  nsIMsgSearchTerm createTerm ();
+  nsIMsgSearchTerm createTerm();
   void appendTerm(in nsIMsgSearchTerm term);
 
   /**
diff --git a/mailnews/base/search/public/nsIMsgSearchValidityTable.idl b/mailnews/base/search/public/nsIMsgSearchValidityTable.idl
index 43856c88be..9b041964c8 100644
--- a/mailnews/base/search/public/nsIMsgSearchValidityTable.idl
+++ b/mailnews/base/search/public/nsIMsgSearchValidityTable.idl
@@ -5,16 +5,7 @@
 
 #include "nsISupports.idl"
 #include "nsMsgSearchCore.idl"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-%{C++
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-%}
-interface nsISupportsArray;
+interface nsIArray;
 
 [scriptable, uuid(b07f1cb6-fae9-4d92-9edb-03f9ad249c66)]
 interface nsIMsgSearchValidityTable : nsISupports {
@@ -33,7 +24,7 @@ interface nsIMsgSearchValidityTable : nsISupports {
     boolean getValidButNotShown(in nsMsgSearchAttribValue attrib,
                                 in nsMsgSearchOpValue op);
 
-    [noscript] void validateTerms(in nsISupportsArray terms);
+    [noscript] void validateTerms(in nsIArray terms);
 
     readonly attribute long numAvailAttribs;
 
diff --git a/mailnews/base/search/public/nsMsgSearchAdapter.h b/mailnews/base/search/public/nsMsgSearchAdapter.h
index 0b1cd71daf..917584763d 100644
--- a/mailnews/base/search/public/nsMsgSearchAdapter.h
+++ b/mailnews/base/search/public/nsMsgSearchAdapter.h
@@ -29,20 +29,20 @@ class nsIMsgSearchScopeTerm;
 class nsMsgSearchAdapter : public nsIMsgSearchAdapter
 {
 public:
-  nsMsgSearchAdapter (nsIMsgSearchScopeTerm*, nsISupportsArray *);
+  nsMsgSearchAdapter (nsIMsgSearchScopeTerm*, nsIArray*);
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSIMSGSEARCHADAPTER
 
   nsIMsgSearchScopeTerm        *m_scope;
-  nsCOMPtr<nsISupportsArray>  m_searchTerms;       /* linked list of criteria terms */
+  nsCOMPtr<nsIArray>  m_searchTerms;       /* linked list of criteria terms */
 
   bool m_abortCalled;
   nsString  m_defaultCharset;
   bool m_forceAsciiSearch;
 
   static nsresult EncodeImap (char **ppEncoding,
-           nsISupportsArray *searchTerms,
+           nsIArray *searchTerms,
            const char16_t *srcCharset,
            const char16_t *destCharset,
            bool reallyDredd = false);
diff --git a/mailnews/base/search/public/nsMsgSearchScopeTerm.h b/mailnews/base/search/public/nsMsgSearchScopeTerm.h
index 74afd8d19d..a02e3f1445 100644
--- a/mailnews/base/search/public/nsMsgSearchScopeTerm.h
+++ b/mailnews/base/search/public/nsMsgSearchScopeTerm.h
@@ -26,7 +26,7 @@ public:
   NS_DECL_NSIMSGSEARCHSCOPETERM
     
   nsresult TimeSlice (bool *aDone);
-  nsresult InitializeAdapter (nsISupportsArray *termList);
+  nsresult InitializeAdapter (nsIArray *termList);
   
   char *GetStatusBarName ();
   
diff --git a/mailnews/base/search/src/nsMsgFilter.cpp b/mailnews/base/search/src/nsMsgFilter.cpp
index e94240f299..df1882980c 100644
--- a/mailnews/base/search/src/nsMsgFilter.cpp
+++ b/mailnews/base/search/src/nsMsgFilter.cpp
@@ -6,6 +6,7 @@
 // this file implements the nsMsgFilter interface
 
 #include "msgCore.h"
+#include "nsArray.h"
 #include "nsMsgBaseCID.h"
 #include "nsIMsgHdr.h"
 #include "nsMsgFilterList.h"    // for kFileVersion
@@ -17,13 +18,13 @@
 #include "nsIMsgIncomingServer.h"
 #include "nsMsgSearchValue.h"
 #include "nsMsgI18N.h"
+#include "nsIMutableArray.h"
 #include "nsIOutputStream.h"
 #include "nsIStringBundle.h"
 #include "nsDateTimeFormatCID.h"
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
 #include "nsIMsgFilterService.h"
-#include "nsIMutableArray.h"
 #include "prmem.h"
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Services.h"
@@ -172,9 +173,8 @@ nsMsgFilter::nsMsgFilter():
     m_filterList(nullptr),
     m_expressionTree(nullptr)
 {
-  nsresult rv = NS_NewISupportsArray(getter_AddRefs(m_termList));
-  if (NS_FAILED(rv))
-    NS_ASSERTION(false, "Failed to allocate a nsISupportsArray for nsMsgFilter");
+  m_termList = nsArray::Create();
+  NS_ASSERTION(m_termList, "Failed to allocate a nsIMutableArray for m_termList");
 
   m_type = nsMsgFilterType::InboxRule | nsMsgFilterType::Manual;
 }
@@ -245,7 +245,7 @@ NS_IMETHODIMP nsMsgFilter::AppendTerm(nsIMsgSearchTerm * aTerm)
     // invalidate expression tree if we're changing the terms
     delete m_expressionTree;
     m_expressionTree = nullptr;
-    return m_termList->AppendElement(static_cast<nsISupports*>(aTerm));
+    return m_termList->AppendElement(aTerm, /* weak = */ false);
 }
 
 NS_IMETHODIMP
@@ -442,7 +442,7 @@ NS_IMETHODIMP nsMsgFilter::GetTerm(int32_t termIndex,
   return NS_OK;
 }
 
-NS_IMETHODIMP nsMsgFilter::GetSearchTerms(nsISupportsArray **aResult)
+NS_IMETHODIMP nsMsgFilter::GetSearchTerms(nsIMutableArray **aResult)
 {
     NS_ENSURE_ARG_POINTER(aResult);
     // caller can change m_termList, which can invalidate m_expressionTree.
@@ -452,7 +452,7 @@ NS_IMETHODIMP nsMsgFilter::GetSearchTerms(nsISupportsArray **aResult)
     return NS_OK;
 }
 
-NS_IMETHODIMP nsMsgFilter::SetSearchTerms(nsISupportsArray *aSearchList)
+NS_IMETHODIMP nsMsgFilter::SetSearchTerms(nsIMutableArray *aSearchList)
 {
     delete m_expressionTree;
     m_expressionTree = nullptr;
diff --git a/mailnews/base/search/src/nsMsgFilter.h b/mailnews/base/search/src/nsMsgFilter.h
index 077baa2ffd..09d05da511 100644
--- a/mailnews/base/search/src/nsMsgFilter.h
+++ b/mailnews/base/search/src/nsMsgFilter.h
@@ -11,6 +11,7 @@
 #include "nsIMsgFilter.h"
 #include "nsIMsgSearchScopeTerm.h"
 #include "nsMsgSearchBoolExpression.h"
+#include "nsIMutableArray.h"
 #include "nsIDateTimeFormat.h"
 #include "nsIMsgFilterCustomAction.h"
 
@@ -92,7 +93,7 @@ protected:
   bool m_temporary;
   bool m_unparseable;
   nsIMsgFilterList *m_filterList;  /* owning filter list */
-  nsCOMPtr<nsISupportsArray> m_termList;       /* linked list of criteria terms */
+  nsCOMPtr<nsIMutableArray> m_termList;       /* linked list of criteria terms */
   nsCOMPtr<nsIMsgSearchScopeTerm> m_scope;         /* default for mail rules is inbox, but news rules could
                                                   have a newsgroup - LDAP would be invalid */
   nsTArray<nsCOMPtr<nsIMsgRuleAction> > m_actionList;
diff --git a/mailnews/base/search/src/nsMsgFilterList.cpp b/mailnews/base/search/src/nsMsgFilterList.cpp
index d5b93fdc26..c4e8b0daf6 100644
--- a/mailnews/base/search/src/nsMsgFilterList.cpp
+++ b/mailnews/base/search/src/nsMsgFilterList.cpp
@@ -1146,11 +1146,11 @@ nsresult nsMsgFilterList::ComputeArbitraryHeaders()
     rv = GetFilterAt(index, getter_AddRefs(filter));
     if (!(NS_SUCCEEDED(rv) && filter)) continue;
 
-    nsCOMPtr <nsISupportsArray> searchTerms;
-    uint32_t numSearchTerms=0;
+    nsCOMPtr<nsIMutableArray> searchTerms;
+    uint32_t numSearchTerms = 0;
     filter->GetSearchTerms(getter_AddRefs(searchTerms));
     if (searchTerms)
-      searchTerms->Count(&numSearchTerms);
+      searchTerms->GetLength(&numSearchTerms);
     for (uint32_t i = 0; i < numSearchTerms; i++)
     {
       filter->GetTerm(i, &attrib, nullptr, nullptr, nullptr, arbitraryHeader);
diff --git a/mailnews/base/search/src/nsMsgFilterService.cpp b/mailnews/base/search/src/nsMsgFilterService.cpp
index 9b2d50d029..a07dd84873 100644
--- a/mailnews/base/search/src/nsMsgFilterService.cpp
+++ b/mailnews/base/search/src/nsMsgFilterService.cpp
@@ -383,7 +383,7 @@ nsresult nsMsgFilterAfterTheFact::RunNextFilter()
     rv = m_filters->GetFilterAt(m_curFilterIndex++, getter_AddRefs(m_curFilter));
     CONTINUE_IF_FAILURE(rv, "Could not get filter at index");
 
-    nsCOMPtr <nsISupportsArray> searchTerms;
+    nsCOMPtr<nsIMutableArray> searchTerms;
     rv = m_curFilter->GetSearchTerms(getter_AddRefs(searchTerms));
     CONTINUE_IF_FAILURE(rv, "Could not get searchTerms");
 
@@ -393,8 +393,8 @@ nsresult nsMsgFilterAfterTheFact::RunNextFilter()
     BREAK_IF_FAILURE(rv, "Failed to get search session");
 
     nsMsgSearchScopeValue searchScope = nsMsgSearchScope::offlineMail;
-    uint32_t termCount;
-    searchTerms->Count(&termCount);
+    uint32_t termCount = 0;
+    searchTerms->GetLength(&termCount);
     for (uint32_t termIndex = 0; termIndex < termCount; termIndex++)
     {
       nsCOMPtr <nsIMsgSearchTerm> term;
diff --git a/mailnews/base/search/src/nsMsgImapSearch.cpp b/mailnews/base/search/src/nsMsgImapSearch.cpp
index 5b3b2698ad..cb828195ee 100644
--- a/mailnews/base/search/src/nsMsgImapSearch.cpp
+++ b/mailnews/base/search/src/nsMsgImapSearch.cpp
@@ -10,18 +10,11 @@
 #include "nsIMsgHdr.h"
 #include "nsMsgSearchImap.h"
 #include "prmem.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 // Implementation of search for IMAP mail folders
 
 
-nsMsgSearchOnlineMail::nsMsgSearchOnlineMail (nsMsgSearchScopeTerm *scope, nsISupportsArray *termList) : nsMsgSearchAdapter (scope, termList)
+nsMsgSearchOnlineMail::nsMsgSearchOnlineMail (nsMsgSearchScopeTerm *scope, nsIArray *termList) : nsMsgSearchAdapter (scope, termList)
 {
 }
 
@@ -83,7 +76,7 @@ nsresult nsMsgSearchOnlineMail::Search (bool *aDone)
 }
 
 nsresult nsMsgSearchOnlineMail::Encode (nsCString& pEncoding,
-                                        nsISupportsArray *searchTerms,
+                                        nsIArray *searchTerms,
                                         const char16_t *destCharset)
 {
   nsCString imapTerms;
@@ -95,7 +88,7 @@ nsresult nsMsgSearchOnlineMail::Encode (nsCString& pEncoding,
   if (true) // !(srcCharset & CODESET_MASK == STATEFUL || srcCharset & CODESET_MASK == WIDECHAR) )   //assume all single/multiple bytes charset has ascii as subset
   {
     uint32_t termCount;
-    searchTerms->Count(&termCount);
+    searchTerms->GetLength(&termCount);
     uint32_t i = 0;
     
     for (i = 0; i < termCount && asciiOnly; i++)
diff --git a/mailnews/base/search/src/nsMsgLocalSearch.cpp b/mailnews/base/search/src/nsMsgLocalSearch.cpp
index 3ce510b6dd..888928b34e 100644
--- a/mailnews/base/search/src/nsMsgLocalSearch.cpp
+++ b/mailnews/base/search/src/nsMsgLocalSearch.cpp
@@ -14,14 +14,7 @@
 #include "nsMsgSearchTerm.h"
 #include "nsMsgResultElement.h"
 #include "nsIDBFolderInfo.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 #include "nsMsgBaseCID.h"
 #include "nsMsgSearchValue.h"
 #include "nsIMsgLocalMailFolder.h"
@@ -237,7 +230,7 @@ void nsMsgSearchBoolExpression::GenerateEncodeStr(nsCString * buffer)
 
 NS_IMPL_ISUPPORTS_INHERITED(nsMsgSearchOfflineMail, nsMsgSearchAdapter, nsIUrlListener)
 
-nsMsgSearchOfflineMail::nsMsgSearchOfflineMail (nsIMsgSearchScopeTerm *scope, nsISupportsArray *termList) : nsMsgSearchAdapter (scope, termList)
+nsMsgSearchOfflineMail::nsMsgSearchOfflineMail (nsIMsgSearchScopeTerm *scope, nsIArray *termList) : nsMsgSearchAdapter (scope, termList)
 {
 }
 
@@ -310,7 +303,7 @@ nsresult nsMsgSearchOfflineMail::OpenSummaryFile ()
 
 nsresult
 nsMsgSearchOfflineMail::MatchTermsForFilter(nsIMsgDBHdr *msgToMatch,
-                                            nsISupportsArray *termList,
+                                            nsIArray *termList,
                                             const char *defaultCharset,
                                             nsIMsgSearchScopeTerm * scope,
                                             nsIMsgDatabase * db,
@@ -325,7 +318,7 @@ nsMsgSearchOfflineMail::MatchTermsForFilter(nsIMsgDBHdr *msgToMatch,
 // static method which matches a header against a list of search terms.
 nsresult
 nsMsgSearchOfflineMail::MatchTermsForSearch(nsIMsgDBHdr *msgToMatch,
-                                            nsISupportsArray* termList,
+                                            nsIArray* termList,
                                             const char *defaultCharset,
                                             nsIMsgSearchScopeTerm *scope,
                                             nsIMsgDatabase *db,
@@ -336,7 +329,7 @@ nsMsgSearchOfflineMail::MatchTermsForSearch(nsIMsgDBHdr *msgToMatch,
     return MatchTerms(msgToMatch, termList, defaultCharset, scope, db, nullptr, 0, false, aExpressionTree, pResult);
 }
 
-nsresult nsMsgSearchOfflineMail::ConstructExpressionTree(nsISupportsArray * termList,
+nsresult nsMsgSearchOfflineMail::ConstructExpressionTree(nsIArray *termList,
                                             uint32_t termCount,
                                             uint32_t &aStartPosInList,
                                             nsMsgSearchBoolExpression ** aExpressionTree)
@@ -664,7 +657,7 @@ nsresult nsMsgSearchOfflineMail::ProcessSearchTerm(nsIMsgDBHdr *msgToMatch,
 }
 
 nsresult nsMsgSearchOfflineMail::MatchTerms(nsIMsgDBHdr *msgToMatch,
-                                            nsISupportsArray * termList,
+                                            nsIArray *termList,
                                             const char *defaultCharset,
                                             nsIMsgSearchScopeTerm * scope,
                                             nsIMsgDatabase * db,
@@ -681,7 +674,7 @@ nsresult nsMsgSearchOfflineMail::MatchTerms(nsIMsgDBHdr *msgToMatch,
   {
     uint32_t initialPos = 0;
     uint32_t count;
-    termList->Count(&count);
+    termList->GetLength(&count);
     err = ConstructExpressionTree(termList, count, initialPos, aExpressionTree);
     if (NS_FAILED(err))
       return err;
@@ -824,7 +817,7 @@ NS_IMETHODIMP nsMsgSearchOfflineMail::OnStopRunningUrl(nsIURI *url, nsresult aEx
   return NS_OK;
 }
 
-nsMsgSearchOfflineNews::nsMsgSearchOfflineNews (nsIMsgSearchScopeTerm *scope, nsISupportsArray *termList) : nsMsgSearchOfflineMail (scope, termList)
+nsMsgSearchOfflineNews::nsMsgSearchOfflineNews (nsIMsgSearchScopeTerm *scope, nsIArray *termList) : nsMsgSearchOfflineMail (scope, termList)
 {
 }
 
diff --git a/mailnews/base/search/src/nsMsgLocalSearch.h b/mailnews/base/search/src/nsMsgLocalSearch.h
index 020d7b5797..1ea2377a86 100644
--- a/mailnews/base/search/src/nsMsgLocalSearch.h
+++ b/mailnews/base/search/src/nsMsgLocalSearch.h
@@ -24,7 +24,7 @@ class nsMsgSearchBoolExpression;
 class nsMsgSearchOfflineMail : public nsMsgSearchAdapter, public nsIUrlListener
 {
 public:
-  nsMsgSearchOfflineMail (nsIMsgSearchScopeTerm*, nsISupportsArray *);
+  nsMsgSearchOfflineMail (nsIMsgSearchScopeTerm*, nsIArray *);
 
   NS_DECL_ISUPPORTS_INHERITED
 
@@ -36,7 +36,7 @@ public:
   NS_IMETHOD AddResultElement (nsIMsgDBHdr *) override;
 
   static nsresult  MatchTermsForFilter(nsIMsgDBHdr * msgToMatch,
-                                         nsISupportsArray *termList,
+                                         nsIArray *termList,
                                          const char *defaultCharset,
                                          nsIMsgSearchScopeTerm *scope,
                                          nsIMsgDatabase * db,
@@ -46,7 +46,7 @@ public:
                      bool *pResult);
 
   static nsresult MatchTermsForSearch(nsIMsgDBHdr * msgTomatch,
-                                      nsISupportsArray * termList,
+                                      nsIArray *termList,
                                       const char *defaultCharset,
                                       nsIMsgSearchScopeTerm *scope,
                                       nsIMsgDatabase *db,
@@ -67,7 +67,7 @@ public:
 protected:
   virtual ~nsMsgSearchOfflineMail();
   static nsresult MatchTerms(nsIMsgDBHdr *msgToMatch,
-                                nsISupportsArray *termList,
+                                nsIArray *termList,
                                 const char *defaultCharset,
                                 nsIMsgSearchScopeTerm *scope,
                                 nsIMsgDatabase * db,
@@ -77,7 +77,7 @@ protected:
                                 nsMsgSearchBoolExpression ** aExpressionTree,
                 bool *pResult);
 
-    static nsresult ConstructExpressionTree(nsISupportsArray * termList,
+    static nsresult ConstructExpressionTree(nsIArray *termList,
                                       uint32_t termCount,
                                       uint32_t &aStartPosInList,
                                       nsMsgSearchBoolExpression ** aExpressionTree);
@@ -91,7 +91,7 @@ protected:
 class nsMsgSearchOfflineNews : public nsMsgSearchOfflineMail
 {
 public:
-  nsMsgSearchOfflineNews (nsIMsgSearchScopeTerm*, nsISupportsArray *);
+  nsMsgSearchOfflineNews (nsIMsgSearchScopeTerm*, nsIArray*);
   virtual ~nsMsgSearchOfflineNews ();
   NS_IMETHOD ValidateTerms () override;
 
diff --git a/mailnews/base/search/src/nsMsgSearchAdapter.cpp b/mailnews/base/search/src/nsMsgSearchAdapter.cpp
index a6f8778305..e0d94b3699 100644
--- a/mailnews/base/search/src/nsMsgSearchAdapter.cpp
+++ b/mailnews/base/search/src/nsMsgSearchAdapter.cpp
@@ -24,14 +24,7 @@
 #include "nsServiceManagerUtils.h"
 #include "nsMemory.h"
 #include "nsMsgMessageFlags.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 #include "nsAlgorithm.h"
 #include <algorithm>
 #include "mozilla/Attributes.h"
@@ -89,7 +82,7 @@ NS_IMETHODIMP nsMsgSearchAdapter::OpenResultElement(nsMsgResultElement *)
 
 NS_IMPL_ISUPPORTS(nsMsgSearchAdapter, nsIMsgSearchAdapter)
 
-nsMsgSearchAdapter::nsMsgSearchAdapter(nsIMsgSearchScopeTerm *scope, nsISupportsArray *searchTerms)
+nsMsgSearchAdapter::nsMsgSearchAdapter(nsIMsgSearchScopeTerm *scope, nsIArray *searchTerms)
   : m_searchTerms(searchTerms)
 {
   m_scope = scope;
@@ -667,7 +660,7 @@ nsresult nsMsgSearchAdapter::EncodeImapValue(char *encoding, const char *value,
 }
 
 
-nsresult nsMsgSearchAdapter::EncodeImap (char **ppOutEncoding, nsISupportsArray *searchTerms, const char16_t *srcCharset, const char16_t *destCharset, bool reallyDredd)
+nsresult nsMsgSearchAdapter::EncodeImap (char **ppOutEncoding, nsIArray *searchTerms, const char16_t *srcCharset, const char16_t *destCharset, bool reallyDredd)
 {
   // i've left the old code (before using CBoolExpression for debugging purposes to make sure that
   // the new code generates the same encoding string as the old code.....
@@ -676,7 +669,7 @@ nsresult nsMsgSearchAdapter::EncodeImap (char **ppOutEncoding, nsISupportsArray
   *ppOutEncoding = nullptr;
 
   uint32_t termCount;
-  searchTerms->Count(&termCount);
+  searchTerms->GetLength(&termCount);
   uint32_t i = 0;
 
   // create our expression
@@ -823,14 +816,14 @@ nsMsgSearchValidityTable::GetNumAvailAttribs(int32_t *aResult)
 }
 
 nsresult
-nsMsgSearchValidityTable::ValidateTerms (nsISupportsArray *searchTerms)
+nsMsgSearchValidityTable::ValidateTerms (nsIArray *searchTerms)
 {
   nsresult err = NS_OK;
   uint32_t count;
 
   NS_ENSURE_ARG(searchTerms);
 
-  searchTerms->Count(&count);
+  searchTerms->GetLength(&count);
   for (uint32_t i = 0; i < count; i++)
   {
     nsCOMPtr<nsIMsgSearchTerm> pTerm;
diff --git a/mailnews/base/search/src/nsMsgSearchImap.h b/mailnews/base/search/src/nsMsgSearchImap.h
index 8f2849da6c..eacb76e6a8 100644
--- a/mailnews/base/search/src/nsMsgSearchImap.h
+++ b/mailnews/base/search/src/nsMsgSearchImap.h
@@ -14,7 +14,7 @@
 class nsMsgSearchOnlineMail : public nsMsgSearchAdapter
 {
 public:
-  nsMsgSearchOnlineMail (nsMsgSearchScopeTerm *scope, nsISupportsArray *termList);
+  nsMsgSearchOnlineMail (nsMsgSearchScopeTerm *scope, nsIArray *termList);
   virtual ~nsMsgSearchOnlineMail ();
 
   NS_IMETHOD ValidateTerms () override;
@@ -23,7 +23,7 @@ public:
   NS_IMETHOD AddResultElement (nsIMsgDBHdr *) override;
 
   static nsresult Encode (nsCString& ppEncoding,
-                            nsISupportsArray *searchTerms,
+                            nsIArray *searchTerms,
                             const char16_t *destCharset);
 
 
diff --git a/mailnews/base/search/src/nsMsgSearchNews.cpp b/mailnews/base/search/src/nsMsgSearchNews.cpp
index 72d2bd6488..99f1d39344 100644
--- a/mailnews/base/search/src/nsMsgSearchNews.cpp
+++ b/mailnews/base/search/src/nsMsgSearchNews.cpp
@@ -15,14 +15,7 @@
 #include "nsIMsgDatabase.h"
 #include "nsMemory.h"
 #include <ctype.h>
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 
 // Implementation of search for IMAP mail folders
 
@@ -40,7 +33,7 @@ const char *nsMsgSearchNews::m_kNntpSubject = "SUBJECT ";
 const char *nsMsgSearchNews::m_kTermSeparator = "/";
 
 
-nsMsgSearchNews::nsMsgSearchNews (nsMsgSearchScopeTerm *scope, nsISupportsArray *termList) : nsMsgSearchAdapter (scope, termList)
+nsMsgSearchNews::nsMsgSearchNews (nsMsgSearchScopeTerm *scope, nsIArray *termList) : nsMsgSearchAdapter (scope, termList)
 {
 }
 
@@ -223,7 +216,7 @@ nsresult nsMsgSearchNews::Encode (nsCString *outEncoding)
 
   uint32_t numTerms;
 
-  m_searchTerms->Count(&numTerms);
+  m_searchTerms->GetLength(&numTerms);
   char **intermediateEncodings = new char * [numTerms];
   if (intermediateEncodings)
   {
@@ -252,7 +245,7 @@ nsresult nsMsgSearchNews::Encode (nsCString *outEncoding)
     {
       PL_strcpy (encoding, "?search");
 
-      m_searchTerms->Count(&numTerms);
+      m_searchTerms->GetLength(&numTerms);
 
       for (i = 0; i < numTerms; i++)
       {
@@ -335,7 +328,7 @@ void nsMsgSearchNews::CollateHits()
     // in the results of each XPAT command. So if we fire 3 XPAT commands (one
     // per search term), the article number must appear 3 times. If it appears
     // fewer than 3 times, it matched some search terms, but not all.
-    m_searchTerms->Count(&termCount);
+    m_searchTerms->GetLength(&termCount);
   }
   uint32_t candidateCount = 0;
   uint32_t candidate = m_candidateHits[0];
diff --git a/mailnews/base/search/src/nsMsgSearchNews.h b/mailnews/base/search/src/nsMsgSearchNews.h
index 5c5c1ec31a..07d65ea31f 100644
--- a/mailnews/base/search/src/nsMsgSearchNews.h
+++ b/mailnews/base/search/src/nsMsgSearchNews.h
@@ -15,7 +15,7 @@
 class nsMsgSearchNews : public nsMsgSearchAdapter
 {
 public:
-  nsMsgSearchNews (nsMsgSearchScopeTerm *scope, nsISupportsArray *termList);
+  nsMsgSearchNews (nsMsgSearchScopeTerm *scope, nsIArray *termList);
   virtual ~nsMsgSearchNews ();
 
   NS_IMETHOD ValidateTerms () override;
diff --git a/mailnews/base/search/src/nsMsgSearchSession.cpp b/mailnews/base/search/src/nsMsgSearchSession.cpp
index 422e17c404..c64a0b303f 100644
--- a/mailnews/base/search/src/nsMsgSearchSession.cpp
+++ b/mailnews/base/search/src/nsMsgSearchSession.cpp
@@ -4,6 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "msgCore.h"
+#include "nsArray.h"
 #include "nsMsgSearchCore.h"
 #include "nsMsgSearchAdapter.h"
 #include "nsMsgSearchBoolExpression.h"
@@ -32,9 +33,8 @@ nsMsgSearchSession::nsMsgSearchSession()
   m_handlingError = false;
   m_expressionTree = nullptr;
   m_searchPaused = false;
-  nsresult rv = NS_NewISupportsArray(getter_AddRefs(m_termList));
-  if (NS_FAILED(rv))
-    NS_ASSERTION(false, "Failed to allocate a nsISupportsArray for nsMsgFilter");
+  m_termList = nsArray::Create();
+  NS_ASSERTION(m_termList, "Failed to allocate a nsIMutableArray for m_termList");
 }
 
 nsMsgSearchSession::~nsMsgSearchSession()
@@ -62,7 +62,7 @@ nsMsgSearchSession::AddSearchTerm(nsMsgSearchAttribValue attrib,
                                                boolOp, customString);
   NS_ENSURE_TRUE(pTerm, NS_ERROR_OUT_OF_MEMORY);
 
-  m_termList->AppendElement(pTerm);
+  m_termList->AppendElement(pTerm, /* weak = */ false);
   // force the expression tree to rebuild whenever we change the terms
   delete m_expressionTree;
   m_expressionTree = nullptr;
@@ -76,11 +76,11 @@ nsMsgSearchSession::AppendTerm(nsIMsgSearchTerm *aTerm)
     NS_ENSURE_TRUE(m_termList, NS_ERROR_NOT_INITIALIZED);
     delete m_expressionTree;
     m_expressionTree = nullptr;
-    return m_termList->AppendElement(aTerm);
+    return m_termList->AppendElement(aTerm, /* weak = */ false);
 }
 
 NS_IMETHODIMP
-nsMsgSearchSession::GetSearchTerms(nsISupportsArray **aResult)
+nsMsgSearchSession::GetSearchTerms(nsIMutableArray **aResult)
 {
     NS_ENSURE_ARG_POINTER(aResult);
     *aResult = m_termList;
@@ -88,6 +88,13 @@ nsMsgSearchSession::GetSearchTerms(nsISupportsArray **aResult)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsMsgSearchSession::SetSearchTerms(nsIMutableArray *aSearchTerms)
+{
+  m_termList = aSearchTerms;
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsMsgSearchSession::CreateTerm(nsIMsgSearchTerm **aResult)
 {
diff --git a/mailnews/base/search/src/nsMsgSearchSession.h b/mailnews/base/search/src/nsMsgSearchSession.h
index d5d62654fe..c31d91dfd9 100644
--- a/mailnews/base/search/src/nsMsgSearchSession.h
+++ b/mailnews/base/search/src/nsMsgSearchSession.h
@@ -12,14 +12,7 @@
 #include "nsIUrlListener.h"
 #include "nsIMsgWindow.h"
 #include "nsITimer.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIMutableArray.h"
 #include "nsCOMArray.h"
 #include "nsWeakReference.h"
 #include "nsTObserverArray.h"
@@ -55,7 +48,7 @@ protected:
   void ReleaseFolderDBRef();
 
   nsTArray<RefPtr<nsMsgSearchScopeTerm>> m_scopeList;
-  nsCOMPtr <nsISupportsArray> m_termList;
+  nsCOMPtr<nsIMutableArray> m_termList;
 
   nsTArray<nsCOMPtr<nsIMsgSearchNotify> > m_listenerList;
   nsTArray<int32_t> m_listenerFlagList;
diff --git a/mailnews/base/search/src/nsMsgSearchTerm.cpp b/mailnews/base/search/src/nsMsgSearchTerm.cpp
index f19491d127..2c6f930425 100644
--- a/mailnews/base/search/src/nsMsgSearchTerm.cpp
+++ b/mailnews/base/search/src/nsMsgSearchTerm.cpp
@@ -1906,7 +1906,7 @@ nsresult nsMsgSearchScopeTerm::TimeSlice (bool *aDone)
   return m_adapter->Search(aDone);
 }
 
-nsresult nsMsgSearchScopeTerm::InitializeAdapter (nsISupportsArray *termList)
+nsresult nsMsgSearchScopeTerm::InitializeAdapter (nsIArray *termList)
 {
   if (m_adapter)
     return NS_OK;
diff --git a/mailnews/base/src/nsMsgAccountManager.cpp b/mailnews/base/src/nsMsgAccountManager.cpp
index 5dd3893b67..7bc25f0b96 100644
--- a/mailnews/base/src/nsMsgAccountManager.cpp
+++ b/mailnews/base/src/nsMsgAccountManager.cpp
@@ -9,14 +9,7 @@
 
 #include "nsIComponentManager.h"
 #include "nsIServiceManager.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIMutableArray.h"
 #include "nsIArray.h"
 #include "nsArrayUtils.h"
 #include "nsMsgAccountManager.h"
@@ -2559,7 +2552,7 @@ nsresult VirtualFolderChangeListener::Init()
     m_searchSession = do_CreateInstance(NS_MSGSEARCHSESSION_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    nsCOMPtr<nsISupportsArray> searchTerms;
+    nsCOMPtr<nsIMutableArray> searchTerms;
     rv = tempFilter->GetSearchTerms(getter_AddRefs(searchTerms));
     NS_ENSURE_SUCCESS(rv, rv);
 
@@ -2573,7 +2566,7 @@ nsresult VirtualFolderChangeListener::Init()
     searchTerms->Count(&numTerms);
     for (uint32_t i = 0; i < numTerms; i++)
     {
-      nsCOMPtr <nsIMsgSearchTerm> searchTerm (do_QueryElementAt(searchTerms, i));
+      nsCOMPtr<nsIMsgSearchTerm> searchTerm(do_QueryElementAt(searchTerms, i));
       nsMsgSearchAttribValue attrib;
       searchTerm->GetAttrib(&attrib);
       if (attrib == nsMsgSearchAttrib::MsgStatus)
diff --git a/mailnews/base/src/nsMsgDBView.cpp b/mailnews/base/src/nsMsgDBView.cpp
index 6ade749dce..e244f93f03 100644
--- a/mailnews/base/src/nsMsgDBView.cpp
+++ b/mailnews/base/src/nsMsgDBView.cpp
@@ -3593,7 +3593,7 @@ nsMsgDBView::PerformActionsOnJunkMsgs(bool msgsAreJunk)
         //  a delete toggle. So what we have to do is to assemble a new delete
         //  array, keeping only those that are not deleted.
         //
-        nsCOMPtr<nsIMutableArray> hdrsToDelete = do_CreateInstance("@mozilla.org/array;1", &rv);
+        nsCOMPtr<nsIMutableArray> hdrsToDelete = do_CreateInstance(NS_ARRAY_CONTRACTID, &rv);
         NS_ENSURE_SUCCESS(rv, rv);
         uint32_t cnt;
         rv = mJunkHdrs->GetLength(&cnt);
diff --git a/mailnews/base/src/nsMsgXFVirtualFolderDBView.cpp b/mailnews/base/src/nsMsgXFVirtualFolderDBView.cpp
index cdc4f0b5a7..06d064b51e 100644
--- a/mailnews/base/src/nsMsgXFVirtualFolderDBView.cpp
+++ b/mailnews/base/src/nsMsgXFVirtualFolderDBView.cpp
@@ -18,6 +18,7 @@
 #include "nsMsgDBCID.h"
 #include "nsMsgMessageFlags.h"
 #include "nsServiceManagerUtils.h"
+#include "nsIMutableArray.h"
 
 nsMsgXFVirtualFolderDBView::nsMsgXFVirtualFolderDBView()
 {
@@ -383,7 +384,7 @@ nsMsgXFVirtualFolderDBView::OnNewSearch()
 
   nsCString terms;
   dbFolderInfo->GetCharProperty("searchStr", terms);
-  nsCOMPtr<nsISupportsArray> searchTerms;
+  nsCOMPtr<nsIMutableArray> searchTerms;
   rv = searchSession->GetSearchTerms(getter_AddRefs(searchTerms));
   NS_ENSURE_SUCCESS(rv, rv);
   nsCString curSearchAsString;
diff --git a/mailnews/base/src/virtualFolderWrapper.js b/mailnews/base/src/virtualFolderWrapper.js
index efb4ed68af..f1cdf38169 100644
--- a/mailnews/base/src/virtualFolderWrapper.js
+++ b/mailnews/base/src/virtualFolderWrapper.js
@@ -29,9 +29,8 @@ var VirtualFolderHelper = {
    * @param aSearchFolders A list of nsIMsgFolders that you want to use as the
    *     sources for the virtual folder OR a string that is the already '|'
    *     delimited list of folder URIs to use.
-   * @param aSearchTerms The search terms to use for the virtual folder.  This
-   *     should be a JS list/nsIMutableArray/nsISupportsArray of
-   *     nsIMsgSearchTermbs.
+   * @param aSearchTerms The search terms to use for the virtual folder. This
+   *     should be a JS list/nsIMutableArray of nsIMsgSearchTerms.
    * @param aOnlineSearch Should the search attempt to use the server's search
    *     capabilities when possible and appropriate?
    *
@@ -133,8 +132,7 @@ VirtualFolderWrapper.prototype = {
    * Set the search folders that back this virtual folder.
    *
    * @param aFolders Either a "|"-delimited string of folder URIs or a list of
-   *     nsIMsgFolders that fixIterator can traverse (JS array/nsIMutableArray/
-   *     nsISupportsArray).
+   *     nsIMsgFolders that fixIterator can traverse (JS array/nsIMutableArray).
    */
   set searchFolders(aFolders) {
     if (typeof(aFolders) == "string") {
@@ -183,7 +181,7 @@ VirtualFolderWrapper.prototype = {
    *  directly.
    *
    * @param aTerms Some collection that fixIterator can traverse.  A JS list or
-   *     XPCOM array (nsIMutableArray or nsISupportsArray) should work.
+   *     XPCOM array (nsIMutableArray) should work.
    */
   set searchTerms(aTerms) {
     let condition = "";
diff --git a/mailnews/base/util/nsMsgIncomingServer.cpp b/mailnews/base/util/nsMsgIncomingServer.cpp
index a1e897f12f..74079044a6 100644
--- a/mailnews/base/util/nsMsgIncomingServer.cpp
+++ b/mailnews/base/util/nsMsgIncomingServer.cpp
@@ -24,6 +24,7 @@
 #include "nsIMsgWindow.h"
 #include "nsIMsgFilterService.h"
 #include "nsIMsgProtocolInfo.h"
+#include "nsIMutableArray.h"
 #include "nsIPrefService.h"
 #include "nsIRelativeFilePref.h"
 #include "nsIDocShell.h"
@@ -1875,7 +1876,7 @@ nsMsgIncomingServer::ConfigureTemporaryServerSpamFilters(nsIMsgFilterList *filte
      */
 
     // get the list of search terms from the filter
-    nsCOMPtr<nsISupportsArray> searchTerms;
+    nsCOMPtr<nsIMutableArray> searchTerms;
     rv = newFilter->GetSearchTerms(getter_AddRefs(searchTerms));
     NS_ENSURE_SUCCESS(rv, rv);
     uint32_t count = 0;
@@ -1911,7 +1912,7 @@ nsMsgIncomingServer::ConfigureTemporaryServerSpamFilters(nsIMsgFilterList *filte
     searchValue->SetStr(NS_LITERAL_STRING("user"));
     searchTerm->SetValue(searchValue);
 
-    searchTerms->InsertElementAt(searchTerm, count);
+    searchTerms->InsertElementAt(searchTerm, count, /* weak = */ false);
 
     bool moveOnSpam, markAsReadOnSpam;
     spamSettings->GetMoveOnSpam(&moveOnSpam);
diff --git a/mailnews/base/util/nsMsgUtils.cpp b/mailnews/base/util/nsMsgUtils.cpp
index 55be45f982..3ace389e3e 100644
--- a/mailnews/base/util/nsMsgUtils.cpp
+++ b/mailnews/base/util/nsMsgUtils.cpp
@@ -58,14 +58,7 @@
 #include "nsIMsgWindow.h"
 #include "nsIWindowWatcher.h"
 #include "nsIPrompt.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 #include "nsIMsgSearchTerm.h"
 #include "nsTextFormatter.h"
 #include "nsIAtomService.h"
@@ -2237,10 +2230,10 @@ NS_MSG_BASE PRTime MsgConvertAgeInDaysToCutoffDate(int32_t ageInDays)
   return now - PR_USEC_PER_DAY * ageInDays;
 }
 
-NS_MSG_BASE nsresult MsgTermListToString(nsISupportsArray *aTermList, nsCString &aOutString)
+NS_MSG_BASE nsresult MsgTermListToString(nsIArray *aTermList, nsCString &aOutString)
 {
   uint32_t count;
-  aTermList->Count(&count);
+  aTermList->GetLength(&count);
   nsresult rv = NS_OK;
 
   for (uint32_t searchIndex = 0; searchIndex < count;
diff --git a/mailnews/base/util/nsMsgUtils.h b/mailnews/base/util/nsMsgUtils.h
index 5cc9c1ddda..265ed77b05 100644
--- a/mailnews/base/util/nsMsgUtils.h
+++ b/mailnews/base/util/nsMsgUtils.h
@@ -14,14 +14,7 @@
 #include "nsTArray.h"
 #include "nsInterfaceRequestorAgg.h"
 #include "nsILoadGroup.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIArray.h"
 #include "nsIAtom.h"
 #include "nsINetUtil.h"
 #include "nsIRequest.h"
@@ -42,7 +35,6 @@ class nsIMsgDatabase;
 class nsIMutableArray;
 class nsIProxyInfo;
 class nsIMsgWindow;
-class nsISupportsArray;
 class nsIStreamListener;
 
 #define FILE_IO_BUFFER_SIZE (16*1024)
@@ -287,7 +279,7 @@ NS_MSG_BASE PRTime MsgConvertAgeInDaysToCutoffDate(int32_t ageInDays);
  * @param[out] aOutString   result representation of search terms.
  *
  */
-NS_MSG_BASE nsresult MsgTermListToString(nsISupportsArray *aTermList, nsCString &aOutString);
+NS_MSG_BASE nsresult MsgTermListToString(nsIArray *aTermList, nsCString &aOutString);
 
 NS_MSG_BASE nsresult
 MsgStreamMsgHeaders(nsIInputStream *aInputStream, nsIStreamListener *aConsumer);
@@ -404,8 +396,7 @@ ConvertBufToPlainText(nsString &aConBuf, bool formatFlowed, bool delsp,
         EndReading()[-1]
 #define SetCharAt(ch, index) \
         Replace(index, 1, ch)
-#define NS_NewISupportsArray(result) \
-        CallCreateInstance(NS_SUPPORTSARRAY_CONTRACTID, static_cast<nsISupportsArray**>(result))
+
 /**
  * The internal and external methods expect the parameters in a different order.
  * The internal API also always expects a flag rather than a comparator.
diff --git a/mailnews/extensions/mailviews/public/nsIMsgMailView.idl b/mailnews/extensions/mailviews/public/nsIMsgMailView.idl
index 54f22e76f1..fdbe06db9b 100644
--- a/mailnews/extensions/mailviews/public/nsIMsgMailView.idl
+++ b/mailnews/extensions/mailviews/public/nsIMsgMailView.idl
@@ -5,31 +5,21 @@
 
 
 #include "nsISupports.idl"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-%{C++
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-%}
-interface nsISupportsArray;
 
+interface nsIMutableArray;
 interface nsIMsgSearchTerm;
 
 [scriptable, uuid(28AC84DF-CBE5-430d-A5C0-4FA63B5424DF)]
 interface nsIMsgMailView : nsISupports {
     attribute wstring mailViewName;
-	readonly attribute wstring prettyName; // localized pretty name
+    readonly attribute wstring prettyName; // localized pretty name
 
-    // the array of search terms 
-    attribute nsISupportsArray searchTerms;
+    // the array of search terms
+    attribute nsIMutableArray searchTerms;
 
     // these two helper methods are required to allow searchTermsOverlay.js to
     // manipulate a mail view without knowing it is dealing with a mail view. nsIMsgFilter
     // and nsIMsgSearchSession have the same two methods....we should probably make an interface around them.
-	void appendTerm(in nsIMsgSearchTerm term);
-	nsIMsgSearchTerm createTerm();
-
+    void appendTerm(in nsIMsgSearchTerm term);
+    nsIMsgSearchTerm createTerm();
 };
diff --git a/mailnews/extensions/mailviews/src/nsMsgMailViewList.cpp b/mailnews/extensions/mailviews/src/nsMsgMailViewList.cpp
index 8e5e04a3f3..d7fdd6722d 100644
--- a/mailnews/extensions/mailviews/src/nsMsgMailViewList.cpp
+++ b/mailnews/extensions/mailviews/src/nsMsgMailViewList.cpp
@@ -4,14 +4,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsMsgMailViewList.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsArray.h"
+#include "nsIMutableArray.h"
 #include "nsIFileChannel.h"
 #include "nsIMsgFilterService.h"
 #include "nsIMsgMailSession.h"
@@ -23,16 +17,18 @@
 #include "nsComponentManagerUtils.h"
 #include "mozilla/Services.h"
 #include "nsIMsgFilter.h"
+#include "nsArrayUtils.h"
 
 #define kDefaultViewPeopleIKnow "People I Know"
 #define kDefaultViewRecent "Recent Mail"
 #define kDefaultViewFiveDays "Last 5 Days"
 #define kDefaultViewNotJunk "Not Junk"
 #define kDefaultViewHasAttachments "Has Attachments"
- 
+
 nsMsgMailView::nsMsgMailView()
 {
-    mViewSearchTerms = do_CreateInstance(NS_SUPPORTSARRAY_CONTRACTID);
+    mViewSearchTerms = nsArray::Create();
+    NS_ASSERTION(mViewSearchTerms, "Failed to allocate a nsIMutableArray for mViewSearchTerms");
 }
 
 NS_IMPL_ADDREF(nsMsgMailView)
@@ -93,24 +89,24 @@ NS_IMETHODIMP nsMsgMailView::GetPrettyName(char16_t ** aMailViewName)
     return rv;
 }
 
-NS_IMETHODIMP nsMsgMailView::GetSearchTerms(nsISupportsArray ** aSearchTerms)
+NS_IMETHODIMP nsMsgMailView::GetSearchTerms(nsIMutableArray **aSearchTerms)
 {
     NS_ENSURE_ARG_POINTER(aSearchTerms);
     NS_IF_ADDREF(*aSearchTerms = mViewSearchTerms);
     return NS_OK;
 }
 
-NS_IMETHODIMP nsMsgMailView::SetSearchTerms(nsISupportsArray * aSearchTerms)
+NS_IMETHODIMP nsMsgMailView::SetSearchTerms(nsIMutableArray *aSearchTerms)
 {
     mViewSearchTerms = aSearchTerms;
     return NS_OK;
 }
 
-NS_IMETHODIMP nsMsgMailView::AppendTerm(nsIMsgSearchTerm * aTerm)
+NS_IMETHODIMP nsMsgMailView::AppendTerm(nsIMsgSearchTerm *aTerm)
 {
     NS_ENSURE_TRUE(aTerm, NS_ERROR_NULL_POINTER);
-    
-    return mViewSearchTerms->AppendElement(static_cast<nsISupports*>(aTerm));
+
+    return mViewSearchTerms->AppendElement(aTerm, /* weak */ false);
 }
 
 NS_IMETHODIMP nsMsgMailView::CreateTerm(nsIMsgSearchTerm **aResult)
@@ -222,7 +218,7 @@ nsresult nsMsgMailViewList::ConvertMailViewListToFilterList()
       if (!newMailFilter)
           continue;
 
-      nsCOMPtr<nsISupportsArray> searchTerms;
+      nsCOMPtr<nsIMutableArray> searchTerms;
       mailView->GetSearchTerms(getter_AddRefs(searchTerms));
       newMailFilter->SetSearchTerms(searchTerms);
       mFilterList->InsertFilterAt(index, newMailFilter);
@@ -298,7 +294,7 @@ nsresult nsMsgMailViewList::ConvertFilterListToMailViews()
         msgFilter->GetFilterName(filterName);
         newMailView->SetMailViewName(filterName.get());
 
-        nsCOMPtr<nsISupportsArray> filterSearchTerms;
+        nsCOMPtr<nsIMutableArray> filterSearchTerms;
         rv = msgFilter->GetSearchTerms(getter_AddRefs(filterSearchTerms));
         NS_ENSURE_SUCCESS(rv, rv);
         rv = newMailView->SetSearchTerms(filterSearchTerms);
diff --git a/mailnews/extensions/mailviews/src/nsMsgMailViewList.h b/mailnews/extensions/mailviews/src/nsMsgMailViewList.h
index 3218033929..e180458de7 100644
--- a/mailnews/extensions/mailviews/src/nsMsgMailViewList.h
+++ b/mailnews/extensions/mailviews/src/nsMsgMailViewList.h
@@ -11,14 +11,7 @@
 #include "nsIMsgMailViewList.h"
 #include "nsCOMPtr.h"
 #include "nsCOMArray.h"
-// Disable deprecation warnings generated by nsISupportsArray and associated
-// classes.
-#if defined(__GNUC__)
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#elif defined(_MSC_VER)
-#pragma warning (disable : 4996)
-#endif
-#include "nsISupportsArray.h"
+#include "nsIMutableArray.h"
 #include "nsIStringBundle.h"
 #include "nsStringGlue.h"
 #include "nsIMsgFilterList.h"
@@ -36,7 +29,7 @@ protected:
   virtual ~nsMsgMailView();
   nsString mName;
   nsCOMPtr<nsIStringBundle> mBundle;
-  nsCOMPtr<nsISupportsArray> mViewSearchTerms;
+  nsCOMPtr<nsIMutableArray> mViewSearchTerms;
 };
 
 
diff --git a/mailnews/imap/src/nsImapMailFolder.cpp b/mailnews/imap/src/nsImapMailFolder.cpp
index fd5f9f17d0..5cb3a1eedd 100644
--- a/mailnews/imap/src/nsImapMailFolder.cpp
+++ b/mailnews/imap/src/nsImapMailFolder.cpp
@@ -691,7 +691,7 @@ NS_IMETHODIMP nsImapMailFolder::UpdateFolderWithListener(nsIMsgWindow *aMsgWindo
         filter->GetEnabled(&enabled);
         if (!enabled)
           continue;
-        nsCOMPtr<nsISupportsArray> searchTerms;
+        nsCOMPtr<nsIMutableArray> searchTerms;
         uint32_t numSearchTerms = 0;
         filter->GetSearchTerms(getter_AddRefs(searchTerms));
         if (searchTerms)
diff --git a/suite/mailnews/commandglue.js b/suite/mailnews/commandglue.js
index 77965c7330..bfa19591a8 100644
--- a/suite/mailnews/commandglue.js
+++ b/suite/mailnews/commandglue.js
@@ -880,7 +880,7 @@ function getSearchTermString(searchTerms)
   var count = searchTerms.Count();
   for (searchIndex = 0; searchIndex < count; )
   {
-    var term = searchTerms.QueryElementAt(searchIndex++, Components.interfaces.nsIMsgSearchTerm);
+    var term = searchTerms.queryElementAt(searchIndex++, Components.interfaces.nsIMsgSearchTerm);
 
     if (condition.length > 1)
       condition += ' ';
@@ -978,26 +978,33 @@ function setupXFVirtualFolderSearch(folderUrisToSearch, searchTerms, searchOnlin
         gSearchSession.addScopeTerm(!searchOnline ? nsMsgSearchScope.offlineMail : GetScopeForFolder(realFolder), realFolder);
     }
 
-    var termsArray = searchTerms.QueryInterface(Components.interfaces.nsISupportsArray);
     const nsIMsgSearchTerm = Components.interfaces.nsIMsgSearchTerm;
-    for (let term in fixIterator(termsArray, nsIMsgSearchTerm)) {
+    for (let term of fixIterator(searchTerms, nsIMsgSearchTerm)) {
       gSearchSession.appendTerm(term);
     }
 }
 
+/**
+ * Uses an array of search terms to produce a new list usable from quick search.
+ *
+ * @param searchTermsArray  A nsIArray of terms to copy.
+ *
+ * @return nsIMutableArray of search terms
+ */
 function CreateGroupedSearchTerms(searchTermsArray)
 {
 
   var searchSession = gSearchSession ||
     Components.classes[searchSessionContractID].createInstance(Components.interfaces.nsIMsgSearchSession);
 
-  // create a temporary isupports array to store our search terms
-  // since we will be modifying the terms so they work with quick search
-  var searchTermsArrayForQS = Components.classes["@mozilla.org/supports-array;1"].createInstance(Components.interfaces.nsISupportsArray);
+  // Create a temporary nsIMutableArray to store our search terms
+  // since we will be modifying the terms so they work with quick search.
+  var searchTermsArrayForQS = Components.classes["@mozilla.org/array;1"]
+                                        .createInstance(Components.interfaces.nsIMutableArray);
 
-  var numEntries = searchTermsArray.Count();
-  for (var i = 0; i < numEntries; i++) {
-    var searchTerm = searchTermsArray.GetElementAt(i).QueryInterface(Components.interfaces.nsIMsgSearchTerm);
+  var numEntries = searchTermsArray.length;
+  for (let i = 0; i < numEntries; i++) {
+    let searchTerm = searchTermsArray.queryElementAt(i, Components.interfaces.nsIMsgSearchTerm);
 
     // clone the term, since we might be modifying it
     var searchTermForQS = searchSession.createTerm();
@@ -1017,7 +1024,7 @@ function CreateGroupedSearchTerms(searchTermsArray)
     // turn the first term to true to work with quick search...
     searchTermForQS.booleanAnd = i ? searchTerm.booleanAnd : true;
 
-    searchTermsArrayForQS.AppendElement(searchTermForQS);
+    searchTermsArrayForQS.appendElement(searchTermForQS, /* weak = */ false);
   }
   return searchTermsArrayForQS;
 }
diff --git a/suite/mailnews/msgViewPickerOverlay.js b/suite/mailnews/msgViewPickerOverlay.js
index c579f09478..adbd2f2c10 100644
--- a/suite/mailnews/msgViewPickerOverlay.js
+++ b/suite/mailnews/msgViewPickerOverlay.js
@@ -210,8 +210,8 @@ function ViewTagKeyword(keyword)
   PrepareForViewChange();
 
   // create an i supports array to store our search terms
-  var searchTermsArray = Components.classes["@mozilla.org/supports-array;1"]
-                                   .createInstance(Components.interfaces.nsISupportsArray);
+  var searchTermsArray = Components.classes["@mozilla.org/array;1"]
+                                   .createInstance(Components.interfaces.nsIMutableArray);
   var term = gSearchSession.createTerm();
   var value = term.value;
 
@@ -222,7 +222,7 @@ function ViewTagKeyword(keyword)
   term.op = nsMsgSearchOp.Contains;
   term.booleanAnd = true;
 
-  searchTermsArray.AppendElement(term);
+  searchTermsArray.appendElement(term, /* weak = */ false);
   AddVirtualFolderTerms(searchTermsArray);
   createSearchTermsWithList(searchTermsArray);
   gDefaultSearchViewTerms = searchTermsArray;
@@ -234,8 +234,8 @@ function ViewNewMail()
   PrepareForViewChange();
 
   // create an i supports array to store our search terms
-  var searchTermsArray = Components.classes["@mozilla.org/supports-array;1"]
-                                   .createInstance(Components.interfaces.nsISupportsArray);
+  var searchTermsArray = Components.classes["@mozilla.org/array;1"]
+                                   .createInstance(Components.interfaces.nsIMutableArray);
   var term = gSearchSession.createTerm();
   var value = term.value;
 
@@ -245,7 +245,7 @@ function ViewNewMail()
   term.attrib = nsMsgSearchAttrib.MsgStatus;
   term.op = nsMsgSearchOp.Isnt;
   term.booleanAnd = true;
-  searchTermsArray.AppendElement(term);
+  searchTermsArray.appendElement(term, /* weak = */ false);
 
   AddVirtualFolderTerms(searchTermsArray);
 
@@ -260,8 +260,8 @@ function ViewNotDeletedMail()
   PrepareForViewChange();
 
   // create an i supports array to store our search terms
-  var searchTermsArray = Components.classes["@mozilla.org/supports-array;1"]
-                                   .createInstance(Components.interfaces.nsISupportsArray);
+  var searchTermsArray = Components.classes["@mozilla.org/array;1"]
+                                   .createInstance(Components.interfaces.nsIMutableArray);
   var term = gSearchSession.createTerm();
   var value = term.value;
 
@@ -271,7 +271,7 @@ function ViewNotDeletedMail()
   term.attrib = nsMsgSearchAttrib.MsgStatus;
   term.op = nsMsgSearchOp.Isnt;
   term.booleanAnd = true;
-  searchTermsArray.AppendElement(term);
+  searchTermsArray.appendElement(term, /* weak = */ false);
 
   AddVirtualFolderTerms(searchTermsArray);
 
@@ -287,14 +287,10 @@ function AddVirtualFolderTerms(searchTermsArray)
   var virtualFolderSearchTerms = (gVirtualFolderTerms || gXFVirtualFolderTerms);
   if (virtualFolderSearchTerms)
   {
-    var isupports = null;
-    var searchTerm;
-    var termsArray = virtualFolderSearchTerms.QueryInterface(Components.interfaces.nsISupportsArray);
-    for (var i = 0; i < termsArray.Count(); i++)
+    for (let i = 0; i < termsArray.length; i++)
     {
-      isupports = termsArray.GetElementAt(i);
-      searchTerm = isupports.QueryInterface(Components.interfaces.nsIMsgSearchTerm);
-      searchTermsArray.AppendElement(searchTerm);
+      let searchTerm = virtualFolderSearchTerms.queryElementAt(i, Components.interfaces.nsIMsgSearchTerm);
+      searchTermsArray.appendElement(searchTerm, /* weak = */ false);
     }
   }
 }
diff --git a/suite/mailnews/search/ABSearchDialog.js b/suite/mailnews/search/ABSearchDialog.js
index 2649ec6bbf..ba1eb79796 100644
--- a/suite/mailnews/search/ABSearchDialog.js
+++ b/suite/mailnews/search/ABSearchDialog.js
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 Components.utils.import("resource:///modules/ABQueryUtils.jsm");
+Components.utils.import("resource:///modules/iteratorUtils.js");
 Components.utils.import("resource:///modules/mailServices.js");
 Components.utils.import("resource://gre/modules/PluralForm.jsm");
 
@@ -165,11 +166,7 @@ function onSearch()
 
     var searchUri = currentAbURI + "?(";
 
-    var count = gSearchSession.searchTerms.Count();
-
-    for (var i=0; i<count; i++) {
-      var searchTerm = gSearchSession.searchTerms.GetElementAt(i).QueryInterface(nsIMsgSearchTerm);
-
+    for (let searchTerm of fixIterator(gSearchSession.searchTerms, nsIMsgSearchTerm)) {
       // get the "and" / "or" value from the first term
       if (i == 0) {
        if (searchTerm.booleanAnd)
diff --git a/suite/mailnews/searchBar.js b/suite/mailnews/searchBar.js
index e1dcaf1f49..d17288c64e 100644
--- a/suite/mailnews/searchBar.js
+++ b/suite/mailnews/searchBar.js
@@ -4,6 +4,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 Components.utils.import("resource://gre/modules/PluralForm.jsm");
+Components.utils.import("resource:///modules/iteratorUtils.jsm");
 
 var gSearchSession = null;
 var gPreQuickSearchView = null;
@@ -172,7 +173,7 @@ function onEnterInSearchBar()
        var addTerms = gDefaultSearchViewTerms || gVirtualFolderTerms || gXFVirtualFolderTerms;
        if (addTerms)
        {
-           viewDebug ("addTerms = " + addTerms + " count = " + addTerms.Count() + "\n");
+           viewDebug ("addTerms = " + addTerms + " count = " + addTerms.length + "\n");
            initializeSearchBar();
            onSearch(addTerms);
        }
@@ -291,10 +292,8 @@ function createSearchTermsWithList(aTermsArray)
   var nsMsgSearchAttrib = Components.interfaces.nsMsgSearchAttrib;
   var nsMsgSearchOp = Components.interfaces.nsMsgSearchOp;
 
+  gSearchSession.clear();
   gSearchSession.clearScopes();
-  var searchTerms = gSearchSession.searchTerms;
-  var searchTermsArray = searchTerms.QueryInterface(Components.interfaces.nsISupportsArray);
-  searchTermsArray.Clear();
 
   var i;
   var selectedFolder = GetThreadPaneFolder();
@@ -320,11 +319,11 @@ function createSearchTermsWithList(aTermsArray)
     viewDebug ("in createSearchTermsWithList, adding scope term for selected folder\n");
     gSearchSession.addScopeTerm(nsMsgSearchScope.offlineMail, selectedFolder);
   }
-  // add each item in termsArray to the search session
 
-  var termsArray = aTermsArray.QueryInterface(Components.interfaces.nsISupportsArray);
-  for (i = 0; i < termsArray.Count(); ++i)
-    gSearchSession.appendTerm(termsArray.GetElementAt(i).QueryInterface(Components.interfaces.nsIMsgSearchTerm));
+  // Add each item in aTermsArray to the search session.
+  for (let term of fixIterator(aTermsArray, Components.interfaces.nsIMsgSearchTerm)) {
+    gSearchSession.appendTerm(term);
+  }
 }
 
 function createSearchTerms()
@@ -333,8 +332,9 @@ function createSearchTerms()
   var nsMsgSearchAttrib = Components.interfaces.nsMsgSearchAttrib;
   var nsMsgSearchOp = Components.interfaces.nsMsgSearchOp;
 
-  // create an nsISupportsArray to store our search terms
-  var searchTermsArray = Components.classes["@mozilla.org/supports-array;1"].createInstance(Components.interfaces.nsISupportsArray);
+  // create an nsIMutableArray to store our search terms
+  var searchTermsArray = Components.classes["@mozilla.org/array;1"]
+                                   .createInstance(Components.interfaces.nsIMutableArray);
   var selectedFolder = GetThreadPaneFolder();
 
   // implement | for QS
@@ -356,7 +356,7 @@ function createSearchTerms()
     term.attrib = nsMsgSearchAttrib.Subject;
     term.op = nsMsgSearchOp.Contains;
     term.booleanAnd = false;
-    searchTermsArray.AppendElement(term);
+    searchTermsArray.appendElement(term, /* weak = */ false);
 
     // create, fill, and append the AllAddresses term
     term = gSearchSession.createTerm();
@@ -366,7 +366,7 @@ function createSearchTerms()
     term.attrib = nsMsgSearchAttrib.AllAddresses;
     term.op = nsMsgSearchOp.Contains;
     term.booleanAnd = false;
-    searchTermsArray.AppendElement(term);
+    searchTermsArray.appendElement(term, /* weak = */ false);
   }
 
   // now append the default view or virtual folder criteria to the quick search
@@ -376,14 +376,9 @@ function createSearchTerms()
   var defaultSearchTerms = (gDefaultSearchViewTerms || gVirtualFolderTerms || gXFVirtualFolderTerms);
   if (defaultSearchTerms)
   {
-    var isupports = null;
-    var searchTerm;
-    var termsArray = defaultSearchTerms.QueryInterface(Components.interfaces.nsISupportsArray);
-    for (i = 0; i < termsArray.Count(); i++)
+    for (let searchTerm of fixIterator(defaultSearchTerms, Components.interfaces.nsIMsgSearchTerm))
     {
-      isupports = termsArray.GetElementAt(i);
-      searchTerm = isupports.QueryInterface(Components.interfaces.nsIMsgSearchTerm);
-      searchTermsArray.AppendElement(searchTerm);
+      searchTermsArray.appendElement(searchTerm, /* weak = */ false);
     }
   }