diff --git a/docshell/base/BrowsingContextGroup.cpp b/docshell/base/BrowsingContextGroup.cpp
index 382a23d7b774..9950235f8be2 100644
--- a/docshell/base/BrowsingContextGroup.cpp
+++ b/docshell/base/BrowsingContextGroup.cpp
@@ -34,11 +34,9 @@ already_AddRefed<BrowsingContextGroup> BrowsingContextGroup::GetOrCreate(
     ClearOnShutdown(&sBrowsingContextGroups);
   }
 
-  return sBrowsingContextGroups->WithEntryHandle(aId, [&aId](auto&& entry) {
-    RefPtr<BrowsingContextGroup> group = entry.OrInsertWith(
-        [&aId] { return do_AddRef(new BrowsingContextGroup(aId)); });
-    return group.forget();
-  });
+  RefPtr<BrowsingContextGroup> group = sBrowsingContextGroups->GetOrInsertWith(
+      aId, [&aId] { return do_AddRef(new BrowsingContextGroup(aId)); });
+  return group.forget();
 }
 
 already_AddRefed<BrowsingContextGroup> BrowsingContextGroup::Create() {
diff --git a/dom/animation/EffectCompositor.cpp b/dom/animation/EffectCompositor.cpp
index 885f8ce07137..737c5c1b1c02 100644
--- a/dom/animation/EffectCompositor.cpp
+++ b/dom/animation/EffectCompositor.cpp
@@ -240,23 +240,14 @@ void EffectCompositor::RequestRestyle(dom::Element* aElement,
   auto& elementsToRestyle = mElementsToRestyle[aCascadeLevel];
   PseudoElementHashEntry::KeyType key = {aElement, aPseudoType};
 
+  bool& restyleEntry = elementsToRestyle.GetOrInsert(key, false);
   if (aRestyleType == RestyleType::Throttled) {
-    elementsToRestyle.WithEntryHandle(
-        key, [](auto&& entry) { entry.OrInsert(false); });
     mPresContext->PresShell()->SetNeedThrottledAnimationFlush();
   } else {
-    // Update hashtable first in case PostRestyleForAnimation mutates it.
+    // Update hashtable first in case PostRestyleForAnimation mutates it
+    // and invalidates the restyleEntry reference.
     // (It shouldn't, but just to be sure.)
-    const bool skipRestyle =
-        elementsToRestyle.WithEntryHandle(key, [](auto&& p) {
-          if (p) {
-            return std::exchange(p.Data(), true);
-          }
-
-          p.Insert(true);
-          return false;
-        });
-
+    bool skipRestyle = std::exchange(restyleEntry, true);
     if (!skipRestyle) {
       PostRestyleForAnimation(aElement, aPseudoType, aCascadeLevel);
     }
diff --git a/dom/base/CustomElementRegistry.cpp b/dom/base/CustomElementRegistry.cpp
index ad886774db25..2a1b002d4f34 100644
--- a/dom/base/CustomElementRegistry.cpp
+++ b/dom/base/CustomElementRegistry.cpp
@@ -1105,12 +1105,8 @@ already_AddRefed<Promise> CustomElementRegistry::WhenDefined(
     return promise.forget();
   }
 
-  return mWhenDefinedPromiseMap
-      .WithEntryHandle(nameAtom,
-                       [&promise](auto&& entry) -> RefPtr<Promise> {
-                         return entry.OrInsert(std::move(promise));
-                       })
-      .forget();
+  return do_AddRef(
+      mWhenDefinedPromiseMap.GetOrInsert(nameAtom, std::move(promise)));
 }
 
 namespace {
diff --git a/dom/base/Document.h b/dom/base/Document.h
index b0ac1f1ca7d1..5a1bd2dedad2 100644
--- a/dom/base/Document.h
+++ b/dom/base/Document.h
@@ -1637,9 +1637,7 @@ class Document : public nsINode,
     RawServoSelectorList* GetListOrInsertFrom(const nsACString& aSelector,
                                               F&& aFrom) {
       MOZ_ASSERT(NS_IsMainThread());
-      return mTable.WithEntryHandle(aSelector, [&aFrom](auto&& entry) {
-        return entry.OrInsertWith(std::forward<F>(aFrom)).get();
-      });
+      return mTable.GetOrInsertWith(aSelector, std::forward<F>(aFrom)).get();
     }
 
     ~SelectorCache();
diff --git a/dom/base/DocumentOrShadowRoot.cpp b/dom/base/DocumentOrShadowRoot.cpp
index f8629d5916cf..e21fd01f3df6 100644
--- a/dom/base/DocumentOrShadowRoot.cpp
+++ b/dom/base/DocumentOrShadowRoot.cpp
@@ -218,11 +218,8 @@ void DocumentOrShadowRoot::CloneAdoptedSheetsFrom(
   MOZ_ASSERT(clonedSheetMap);
 
   for (const StyleSheet* sheet : aSource.mAdoptedStyleSheets) {
-    RefPtr<StyleSheet> clone = clonedSheetMap->WithEntryHandle(
-        sheet, [&sheet, &ownerDoc](auto&& entry) {
-          return entry.OrInsertWith(
-              [&] { return sheet->CloneAdoptedSheet(ownerDoc); });
-        });
+    RefPtr<StyleSheet> clone = clonedSheetMap->GetOrInsertWith(
+        sheet, [&] { return sheet->CloneAdoptedSheet(ownerDoc); });
     MOZ_ASSERT(clone);
     MOZ_DIAGNOSTIC_ASSERT(clone->ConstructorDocumentMatches(ownerDoc));
     DebugOnly<bool> succeeded = list.AppendElement(std::move(clone), fallible);
@@ -755,10 +752,9 @@ nsRadioGroupStruct* DocumentOrShadowRoot::GetRadioGroup(
 
 nsRadioGroupStruct* DocumentOrShadowRoot::GetOrCreateRadioGroup(
     const nsAString& aName) {
-  return mRadioGroups.WithEntryHandle(aName, [](auto&& entry) {
-    return entry.OrInsertWith([] { return MakeUnique<nsRadioGroupStruct>(); })
-        .get();
-  });
+  return mRadioGroups
+      .GetOrInsertWith(aName, [] { return MakeUnique<nsRadioGroupStruct>(); })
+      .get();
 }
 
 int32_t DocumentOrShadowRoot::StyleOrderIndexOfSheet(
diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 08ab1587dc97..f1ea519eb81b 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -3954,14 +3954,12 @@ void Element::RegisterIntersectionObserver(DOMIntersectionObserver* aObserver) {
     return;
   }
 
-  observers->WithEntryHandle(aObserver, [](auto&& entry) {
-    // Value can be:
-    //   -2:   Makes sure next calculated threshold always differs, leading to a
-    //         notification task being scheduled.
-    //   -1:   Non-intersecting.
-    //   >= 0: Intersecting, valid index of aObserver->mThresholds.
-    entry.OrInsert(eUninitialized);
-  });
+  // Value can be:
+  //   -2:   Makes sure next calculated threshold always differs, leading to a
+  //         notification task being scheduled.
+  //   -1:   Non-intersecting.
+  //   >= 0: Intersecting, valid index of aObserver->mThresholds.
+  Unused << observers->GetOrInsert(aObserver, eUninitialized);
 }
 
 void Element::UnregisterIntersectionObserver(
diff --git a/dom/base/ResizeObserver.cpp b/dom/base/ResizeObserver.cpp
index 1fd2f244d577..7dd6a427dc46 100644
--- a/dom/base/ResizeObserver.cpp
+++ b/dom/base/ResizeObserver.cpp
@@ -150,10 +150,7 @@ void ResizeObserver::Observe(Element& aTarget,
     mDocument->AddResizeObserver(*this);
   }
 
-  auto& observation = mObservationMap.WithEntryHandle(
-      &aTarget, [](auto&& entry) -> RefPtr<ResizeObservation>& {
-        return entry.OrInsert(nullptr);
-      });
+  auto& observation = mObservationMap.GetOrInsert(&aTarget);
   if (observation) {
     if (observation->BoxOptions() == aOptions.mBox) {
       // Already observed this target and the observed box is the same, so
diff --git a/dom/base/nsDOMMutationObserver.cpp b/dom/base/nsDOMMutationObserver.cpp
index f57a04f5ffc2..2aa35b41e8e9 100644
--- a/dom/base/nsDOMMutationObserver.cpp
+++ b/dom/base/nsDOMMutationObserver.cpp
@@ -320,15 +320,15 @@ void nsMutationReceiver::ContentRemoved(nsIContent* aChild,
       bool transientExists = false;
       bool isNewEntry = false;
       auto* const transientReceivers =
-          Observer()->mTransientReceivers.WithEntryHandle(
-              aChild, [&isNewEntry](auto&& entry) {
-                return entry
-                    .OrInsertWith([&isNewEntry] {
-                      isNewEntry = true;
-                      return MakeUnique<nsCOMArray<nsMutationReceiver>>();
-                    })
-                    .get();
-              });
+          Observer()
+              ->mTransientReceivers
+              .GetOrInsertWith(
+                  aChild,
+                  [&isNewEntry] {
+                    isNewEntry = true;
+                    return MakeUnique<nsCOMArray<nsMutationReceiver>>();
+                  })
+              .get();
       if (!isNewEntry) {
         for (int32_t i = 0; i < transientReceivers->Count(); ++i) {
           nsMutationReceiver* r = transientReceivers->ObjectAt(i);
@@ -1039,13 +1039,11 @@ void nsAutoMutationBatch::Done() {
 
       if (allObservers.Length()) {
         auto* const transientReceivers =
-            ob->mTransientReceivers.WithEntryHandle(removed, [](auto&& entry) {
-              return entry
-                  .OrInsertWith([] {
-                    return MakeUnique<nsCOMArray<nsMutationReceiver>>();
-                  })
-                  .get();
-            });
+            ob->mTransientReceivers
+                .GetOrInsertWith(
+                    removed,
+                    [] { return MakeUnique<nsCOMArray<nsMutationReceiver>>(); })
+                .get();
         for (uint32_t k = 0; k < allObservers.Length(); ++k) {
           nsMutationReceiver* r = allObservers[k];
           nsMutationReceiver* orig = r->GetParent() ? r->GetParent() : r;
diff --git a/dom/base/nsFrameMessageManager.cpp b/dom/base/nsFrameMessageManager.cpp
index 7677e2345383..e08cfdbb7f8f 100644
--- a/dom/base/nsFrameMessageManager.cpp
+++ b/dom/base/nsFrameMessageManager.cpp
@@ -240,14 +240,14 @@ void nsFrameMessageManager::AddMessageListener(const nsAString& aMessageName,
                                                bool aListenWhenClosed,
                                                ErrorResult& aError) {
   auto* const listeners =
-      mListeners.WithEntryHandle(aMessageName, [](auto&& entry) {
-        return entry
-            .OrInsertWith([] {
-              return MakeUnique<
-                  nsAutoTObserverArray<nsMessageListenerInfo, 1>>();
-            })
-            .get();
-      });
+      mListeners
+          .GetOrInsertWith(
+              aMessageName,
+              [] {
+                return MakeUnique<
+                    nsAutoTObserverArray<nsMessageListenerInfo, 1>>();
+              })
+          .get();
   uint32_t len = listeners->Length();
   for (uint32_t i = 0; i < len; ++i) {
     MessageListener* strongListener = listeners->ElementAt(i).mStrongListener;
@@ -315,14 +315,14 @@ void nsFrameMessageManager::AddWeakMessageListener(
 #endif
 
   auto* const listeners =
-      mListeners.WithEntryHandle(aMessageName, [](auto&& entry) {
-        return entry
-            .OrInsertWith([] {
-              return MakeUnique<
-                  nsAutoTObserverArray<nsMessageListenerInfo, 1>>();
-            })
-            .get();
-      });
+      mListeners
+          .GetOrInsertWith(
+              aMessageName,
+              [] {
+                return MakeUnique<
+                    nsAutoTObserverArray<nsMessageListenerInfo, 1>>();
+              })
+          .get();
   uint32_t len = listeners->Length();
   for (uint32_t i = 0; i < len; ++i) {
     if (listeners->ElementAt(i).mWeakListener == weak) {
diff --git a/dom/base/nsGlobalWindowInner.cpp b/dom/base/nsGlobalWindowInner.cpp
index 3eda4135c827..2da36ad2b9c8 100644
--- a/dom/base/nsGlobalWindowInner.cpp
+++ b/dom/base/nsGlobalWindowInner.cpp
@@ -7160,13 +7160,13 @@ ChromeMessageBroadcaster* nsGlobalWindowInner::GetGroupMessageManager(
     const nsAString& aGroup) {
   MOZ_ASSERT(IsChromeWindow());
 
-  return mChromeFields.mGroupMessageManagers.WithEntryHandle(
-      aGroup, [&](auto&& entry) {
-        return entry
-            .OrInsertWith(
-                [&] { return new ChromeMessageBroadcaster(MessageManager()); })
-            .get();
-      });
+  return mChromeFields.mGroupMessageManagers
+      .GetOrInsertWith(
+          aGroup,
+          [&] {
+            return MakeAndAddRef<ChromeMessageBroadcaster>(MessageManager());
+          })
+      .get();
 }
 
 void nsGlobalWindowInner::InitWasOffline() { mWasOffline = NS_IsOffline(); }
diff --git a/dom/broadcastchannel/BroadcastChannelService.cpp b/dom/broadcastchannel/BroadcastChannelService.cpp
index 610b8452374d..8b475cc2952b 100644
--- a/dom/broadcastchannel/BroadcastChannelService.cpp
+++ b/dom/broadcastchannel/BroadcastChannelService.cpp
@@ -82,12 +82,11 @@ void BroadcastChannelService::RegisterActor(
   MOZ_ASSERT(aParent);
 
   auto* const parents =
-      mAgents.WithEntryHandle(aOriginChannelKey, [](auto&& entry) {
-        return entry
-            .OrInsertWith(
-                [] { return MakeUnique<nsTArray<BroadcastChannelParent*>>(); })
-            .get();
-      });
+      mAgents
+          .GetOrInsertWith(
+              aOriginChannelKey,
+              [] { return MakeUnique<nsTArray<BroadcastChannelParent*>>(); })
+          .get();
 
   MOZ_ASSERT(!parents->Contains(aParent));
   parents->AppendElement(aParent);
diff --git a/dom/commandhandler/nsCommandManager.cpp b/dom/commandhandler/nsCommandManager.cpp
index 5490482e38f7..ecf1d391ada8 100644
--- a/dom/commandhandler/nsCommandManager.cpp
+++ b/dom/commandhandler/nsCommandManager.cpp
@@ -81,11 +81,10 @@ nsCommandManager::AddCommandObserver(nsIObserver* aCommandObserver,
 
   // for each command in the table, we make a list of observers for that command
   auto* const commandObservers =
-      mObserversTable.WithEntryHandle(aCommandToObserve, [](auto&& entry) {
-        return entry
-            .OrInsertWith([] { return mozilla::MakeUnique<ObserverList>(); })
-            .get();
-      });
+      mObserversTable
+          .GetOrInsertWith(aCommandToObserve,
+                           [] { return mozilla::MakeUnique<ObserverList>(); })
+          .get();
 
   // need to check that this command observer hasn't already been registered
   int32_t existingIndex = commandObservers->IndexOf(aCommandObserver);
diff --git a/dom/events/EventListenerService.cpp b/dom/events/EventListenerService.cpp
index d10643d07574..f8c21e72d50b 100644
--- a/dom/events/EventListenerService.cpp
+++ b/dom/events/EventListenerService.cpp
@@ -374,12 +374,10 @@ void EventListenerService::NotifyAboutMainThreadListenerChangeInternal(
   }
 
   RefPtr<EventListenerChange> changes =
-      mPendingListenerChangesSet.WithEntryHandle(aTarget, [&](auto&& entry) {
-        return entry.OrInsertWith([&] {
-          EventListenerChange* c = new EventListenerChange(aTarget);
-          mPendingListenerChanges->AppendElement(c);
-          return c;
-        });
+      mPendingListenerChangesSet.GetOrInsertWith(aTarget, [&] {
+        auto c = MakeRefPtr<EventListenerChange>(aTarget);
+        mPendingListenerChanges->AppendElement(c);
+        return c;
       });
   changes->AddChangedListenerName(aName);
 }
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 554032036701..33b2a7f024ff 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -4696,11 +4696,10 @@ OverOutElementsWrapper* EventStateManager::GetWrapperByEventID(
     }
     return mMouseEnterLeaveHelper;
   }
-  return mPointersEnterLeaveHelper.WithEntryHandle(
-      pointer->pointerId, [](auto&& entry) {
-        return entry.OrInsertWith([] { return new OverOutElementsWrapper(); })
-            .get();
-      });
+  return mPointersEnterLeaveHelper
+      .GetOrInsertWith(pointer->pointerId,
+                       [] { return new OverOutElementsWrapper(); })
+      .get();
 }
 
 /* static */
diff --git a/dom/html/HTMLAllCollection.cpp b/dom/html/HTMLAllCollection.cpp
index 487a6aca46d4..445c8cbc0a85 100644
--- a/dom/html/HTMLAllCollection.cpp
+++ b/dom/html/HTMLAllCollection.cpp
@@ -104,15 +104,14 @@ static bool DocAllResultMatch(Element* aElement, int32_t aNamespaceID,
 }
 
 nsContentList* HTMLAllCollection::GetDocumentAllList(const nsAString& aID) {
-  return mNamedMap.WithEntryHandle(aID, [&](auto&& entry) {
-    return entry
-        .OrInsertWith([this, &aID] {
-          RefPtr<nsAtom> id = NS_Atomize(aID);
-          return new nsContentList(mDocument, DocAllResultMatch, nullptr,
-                                   nullptr, true, id);
-        })
-        .get();
-  });
+  return mNamedMap
+      .GetOrInsertWith(aID,
+                       [this, &aID] {
+                         RefPtr<nsAtom> id = NS_Atomize(aID);
+                         return new nsContentList(mDocument, DocAllResultMatch,
+                                                  nullptr, nullptr, true, id);
+                       })
+      .get();
 }
 
 void HTMLAllCollection::NamedGetter(
diff --git a/dom/html/HTMLFormElement.cpp b/dom/html/HTMLFormElement.cpp
index fb336d6701a3..f8498559ca68 100644
--- a/dom/html/HTMLFormElement.cpp
+++ b/dom/html/HTMLFormElement.cpp
@@ -2170,10 +2170,8 @@ HTMLFormElement::WalkRadioGroup(const nsAString& aName,
 void HTMLFormElement::AddToRadioGroup(const nsAString& aName,
                                       HTMLInputElement* aRadio) {
   if (aRadio->IsRequired()) {
-    mRequiredRadioButtonCounts.WithEntryHandle(aName, [](auto&& entry) {
-      uint32_t& value = entry.OrInsert(0);
-      ++value;
-    });
+    uint32_t& value = mRequiredRadioButtonCounts.GetOrInsert(aName, 0);
+    ++value;
   }
 }
 
diff --git a/dom/localstorage/ActorsParent.cpp b/dom/localstorage/ActorsParent.cpp
index c0fc33b27a2c..d37350938a67 100644
--- a/dom/localstorage/ActorsParent.cpp
+++ b/dom/localstorage/ActorsParent.cpp
@@ -5451,8 +5451,7 @@ void Snapshot::SaveItem(const nsAString& aKey, const LSValue& aOldValue,
   }
 
   if (!mLoadedItems.GetEntry(aKey) && !mUnknownItems.GetEntry(aKey)) {
-    mValues.WithEntryHandle(aKey,
-                            [&](auto&& entry) { entry.OrInsert(aOldValue); });
+    Unused << mValues.GetOrInsert(aKey, aOldValue);
   }
 
   if (aAffectsOrder && !mSavedKeys) {
diff --git a/dom/media/ogg/OggCodecState.cpp b/dom/media/ogg/OggCodecState.cpp
index 8a3dc6129500..5ddc19f243fa 100644
--- a/dom/media/ogg/OggCodecState.cpp
+++ b/dom/media/ogg/OggCodecState.cpp
@@ -1712,14 +1712,13 @@ bool SkeletonState::DecodeFisbone(ogg_packet* aPacket) {
 
           if ((i == 0 && IsAscii(strMsg)) || (i != 0 && IsUtf8(strMsg))) {
             EMsgHeaderType eHeaderType = kFieldTypeMaps[i].mMsgHeaderType;
-            field->mValuesStore.WithEntryHandle(eHeaderType, [=](auto&& entry) {
-              entry.OrInsertWith([i, msgHead, msgProbe]() {
-                uint32_t nameLen =
-                    strlen(kFieldTypeMaps[i].mPatternToRecognize);
-                return MakeUnique<nsCString>(msgHead + nameLen,
-                                             msgProbe - msgHead - nameLen);
-              });
-            });
+            Unused << field->mValuesStore.GetOrInsertWith(
+                eHeaderType, [i, msgHead, msgProbe]() {
+                  uint32_t nameLen =
+                      strlen(kFieldTypeMaps[i].mPatternToRecognize);
+                  return MakeUnique<nsCString>(msgHead + nameLen,
+                                               msgProbe - msgHead - nameLen);
+                });
             isContentTypeParsed = i == 0 ? true : isContentTypeParsed;
           }
           break;
diff --git a/dom/payments/PaymentRequestManager.cpp b/dom/payments/PaymentRequestManager.cpp
index 8d502f21fc6c..20c9b1e9736f 100644
--- a/dom/payments/PaymentRequestManager.cpp
+++ b/dom/payments/PaymentRequestManager.cpp
@@ -380,8 +380,7 @@ nsresult PaymentRequestManager::SendRequestPayment(
   }
 
   if (aResponseExpected) {
-    mActivePayments.WithEntryHandle(aRequest,
-                                    [](auto&& count) { ++count.OrInsert(0); });
+    ++mActivePayments.GetOrInsert(aRequest, 0);
   }
   return NS_OK;
 }
diff --git a/dom/quota/ActorsParent.cpp b/dom/quota/ActorsParent.cpp
index 4264bb2f6b6b..4a3f6ca1fc4f 100644
--- a/dom/quota/ActorsParent.cpp
+++ b/dom/quota/ActorsParent.cpp
@@ -4368,15 +4368,12 @@ already_AddRefed<QuotaObject> QuotaManager::GetQuotaObject(
     // pointer directly since QuotaObject::AddRef would try to acquire the same
     // mutex.
     const NotNull<QuotaObject*> quotaObject =
-        originInfo->mQuotaObjects.WithEntryHandle(
-            path, [&](auto&& entryHandle) {
-              return entryHandle.OrInsertWith([&] {
-                // Create a new QuotaObject. The hashtable is not responsible to
-                // delete the QuotaObject.
-                return WrapNotNullUnchecked(
-                    new QuotaObject(originInfo, aClientType, path, fileSize));
-              });
-            });
+        originInfo->mQuotaObjects.GetOrInsertWith(path, [&] {
+          // Create a new QuotaObject. The hashtable is not responsible to
+          // delete the QuotaObject.
+          return WrapNotNullUnchecked(
+              new QuotaObject(originInfo, aClientType, path, fileSize));
+        });
 
     // Addref the QuotaObject and move the ownership to the result. This must
     // happen before we unlock!
@@ -6941,21 +6938,16 @@ auto QuotaManager::GetDirectoryLockTable(PersistenceType aPersistenceType)
 bool QuotaManager::IsSanitizedOriginValid(const nsACString& aSanitizedOrigin) {
   AssertIsOnIOThread();
 
-  return mValidOrigins.WithEntryHandle(
-      aSanitizedOrigin, [&aSanitizedOrigin](auto&& entry) {
-        if (entry) {
-          // We already parsed this sanitized origin string.
-          return entry.Data();
-        }
+  // Do not parse this sanitized origin string, if we already parsed it.
+  return mValidOrigins.GetOrInsertWith(aSanitizedOrigin, [&aSanitizedOrigin] {
+    nsCString spec;
+    OriginAttributes attrs;
+    nsCString originalSuffix;
+    const auto result = OriginParser::ParseOrigin(aSanitizedOrigin, spec,
+                                                  &attrs, originalSuffix);
 
-        nsCString spec;
-        OriginAttributes attrs;
-        nsCString originalSuffix;
-        const auto result = OriginParser::ParseOrigin(aSanitizedOrigin, spec,
-                                                      &attrs, originalSuffix);
-
-        return entry.Insert(result == OriginParser::ValidOrigin);
-      });
+    return result == OriginParser::ValidOrigin;
+  });
 }
 
 int64_t QuotaManager::GenerateDirectoryLockId() {
diff --git a/dom/serviceworkers/ServiceWorkerManager.cpp b/dom/serviceworkers/ServiceWorkerManager.cpp
index 65f8bf695573..1acf7ff2ca8c 100644
--- a/dom/serviceworkers/ServiceWorkerManager.cpp
+++ b/dom/serviceworkers/ServiceWorkerManager.cpp
@@ -1594,13 +1594,9 @@ ServiceWorkerManager::GetOrCreateJobQueue(const nsACString& aKey,
             .get();
   }
 
-  return data->mJobQueues
-      .WithEntryHandle(aScope,
-                       [](auto&& entry) {
-                         return entry.OrInsertWith(
-                             [] { return new ServiceWorkerJobQueue(); });
-                       })
-      .forget();
+  RefPtr queue = data->mJobQueues.GetOrInsertWith(
+      aScope, [] { return new ServiceWorkerJobQueue(); });
+  return queue.forget();
 }
 
 /* static */
@@ -1911,12 +1907,11 @@ void ServiceWorkerManager::AddScopeAndRegistration(
   MOZ_ASSERT(!scopeKey.IsEmpty());
 
   auto* const data =
-      swm->mRegistrationInfos.WithEntryHandle(scopeKey, [](auto&& entry) {
-        return entry
-            .OrInsertWith(
-                [] { return MakeUnique<RegistrationDataPerPrincipal>(); })
-            .get();
-      });
+      swm->mRegistrationInfos
+          .GetOrInsertWith(
+              scopeKey,
+              [] { return MakeUnique<RegistrationDataPerPrincipal>(); })
+          .get();
 
   data->mScopeContainer.InsertScope(aScope);
   data->mInfos.Put(aScope, RefPtr{aInfo});
diff --git a/dom/storage/SessionStorageManager.cpp b/dom/storage/SessionStorageManager.cpp
index 51b12c2ba4de..8c19152d665c 100644
--- a/dom/storage/SessionStorageManager.cpp
+++ b/dom/storage/SessionStorageManager.cpp
@@ -632,11 +632,10 @@ BackgroundSessionStorageManager* BackgroundSessionStorageManager::GetOrCreate(
         }));
   }
 
-  return sManagers->WithEntryHandle(aTopContextId, [](auto&& entry) {
-    return entry
-        .OrInsertWith([] { return new BackgroundSessionStorageManager(); })
-        .get();
-  });
+  return sManagers
+      ->GetOrInsertWith(aTopContextId,
+                        [] { return new BackgroundSessionStorageManager(); })
+      .get();
 }
 
 BackgroundSessionStorageManager::BackgroundSessionStorageManager() {
diff --git a/dom/workers/RuntimeService.cpp b/dom/workers/RuntimeService.cpp
index e7df6ded13a3..0bfdf3cc978b 100644
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@@ -1150,18 +1150,18 @@ bool RuntimeService::RegisterWorker(WorkerPrivate& aWorkerPrivate) {
     MutexAutoLock lock(mMutex);
 
     auto* const domainInfo =
-        mDomainMap.WithEntryHandle(domain, [&](auto&& entry) {
-          return entry
-              .OrInsertWith([&domain, parent] {
-                NS_ASSERTION(!parent, "Shouldn't have a parent here!");
-                Unused << parent;  // silence clang -Wunused-lambda-capture in
-                                   // opt builds
-                auto wdi = MakeUnique<WorkerDomainInfo>();
-                wdi->mDomain = domain;
-                return wdi;
-              })
-              .get();
-        });
+        mDomainMap
+            .GetOrInsertWith(
+                domain,
+                [&domain, parent] {
+                  NS_ASSERTION(!parent, "Shouldn't have a parent here!");
+                  Unused << parent;  // silence clang -Wunused-lambda-capture in
+                                     // opt builds
+                  auto wdi = MakeUnique<WorkerDomainInfo>();
+                  wdi->mDomain = domain;
+                  return wdi;
+                })
+            .get();
 
     queued = gMaxWorkersPerDomain &&
              domainInfo->ActiveWorkerCount() >= gMaxWorkersPerDomain &&
@@ -1222,14 +1222,12 @@ bool RuntimeService::RegisterWorker(WorkerPrivate& aWorkerPrivate) {
     if (!isServiceWorker) {
       // Service workers are excluded since their lifetime is separate from
       // that of dom windows.
-      if (auto* const windowArray = mWindowMap.WithEntryHandle(
-              window,
-              [](auto&& entry) {
-                return entry
-                    .OrInsertWith(
-                        [] { return MakeUnique<nsTArray<WorkerPrivate*>>(1); })
-                    .get();
-              });
+      if (auto* const windowArray =
+              mWindowMap
+                  .GetOrInsertWith(
+                      window,
+                      [] { return MakeUnique<nsTArray<WorkerPrivate*>>(1); })
+                  .get();
           !windowArray->Contains(&aWorkerPrivate)) {
         windowArray->AppendElement(&aWorkerPrivate);
       } else {
diff --git a/gfx/gl/GLContextProviderEGL.cpp b/gfx/gl/GLContextProviderEGL.cpp
index f7c2bde0a866..64cb450f77a9 100644
--- a/gfx/gl/GLContextProviderEGL.cpp
+++ b/gfx/gl/GLContextProviderEGL.cpp
@@ -867,11 +867,9 @@ EGLSurface GLContextEGL::CreateWaylandBufferSurface(
       config, reinterpret_cast<EGLNativeWindowType>(eglwindow), 0);
   if (surface) {
 #ifdef MOZ_GTK_WAYLAND
-    WaylandGLSurface* waylandData = new WaylandGLSurface(wlsurface, eglwindow);
-    // XXX This looks as if this should unconditionally insert. Otherwise,
-    // waylandData would be leaked.
-    sWaylandGLSurface.WithEntryHandle(
-        surface, [&](auto&& entry) { entry.OrInsert(waylandData); });
+    MOZ_ASSERT(!sWaylandGLSurface.Contains(surface));
+    sWaylandGLSurface.GetOrInsert(surface,
+                                  new WaylandGLSurface(wlsurface, eglwindow));
 #endif
   }
 
diff --git a/gfx/thebes/gfxFcPlatformFontList.cpp b/gfx/thebes/gfxFcPlatformFontList.cpp
index d6b60aa210a0..e78a0a8038ea 100644
--- a/gfx/thebes/gfxFcPlatformFontList.cpp
+++ b/gfx/thebes/gfxFcPlatformFontList.cpp
@@ -1591,17 +1591,22 @@ void gfxFcPlatformFontList::InitSharedFontListForPlatform() {
       aFamilyName = ToCharPtr(canonical);
 
       // Add new family record if one doesn't already exist.
-      faceListPtr = faces.WithEntryHandle(keyName, [&](auto&& faceList) {
-        if (!faceList) {
-          faceList.Insert(MakeUnique<FaceInitArray>());
-          FontVisibility visibility =
-              aAppFont ? FontVisibility::Base : GetVisibilityForFamily(keyName);
-          families.AppendElement(fontlist::Family::InitData(
-              keyName, aFamilyName, fontlist::Family::kNoIndex, visibility,
-              /*bundled*/ aAppFont, /*badUnderline*/ false));
-        }
-        return faceList.Data().get();
-      });
+      faceListPtr =
+          faces
+              .GetOrInsertWith(
+                  keyName,
+                  [&] {
+                    FontVisibility visibility =
+                        aAppFont ? FontVisibility::Base
+                                 : GetVisibilityForFamily(keyName);
+                    families.AppendElement(fontlist::Family::InitData(
+                        keyName, aFamilyName, fontlist::Family::kNoIndex,
+                        visibility,
+                        /*bundled*/ aAppFont, /*badUnderline*/ false));
+
+                    return MakeUnique<FaceInitArray>();
+                  })
+              .get();
     }
 
     char* s = (char*)FcNameUnparse(aPattern);
@@ -1650,18 +1655,21 @@ void gfxFcPlatformFontList::InitSharedFontListForPlatform() {
       keyName = otherFamilyName;
       ToLowerCase(keyName);
 
-      faces.WithEntryHandle(keyName, [&](auto&& faceList) {
-        if (!faceList) {
-          faceList.Insert(MakeUnique<FaceInitArray>());
-          FontVisibility visibility =
-              aAppFont ? FontVisibility::Base : GetVisibilityForFamily(keyName);
-          families.AppendElement(fontlist::Family::InitData(
-              keyName, otherFamilyName, fontlist::Family::kNoIndex, visibility,
-              /*bundled*/ aAppFont, /*badUnderline*/ false));
-        }
-        faceList.Data()->AppendElement(fontlist::Face::InitData{
-            descriptor, 0, false, weight, stretch, style});
-      });
+      faces
+          .GetOrInsertWith(keyName,
+                           [&] {
+                             FontVisibility visibility =
+                                 aAppFont ? FontVisibility::Base
+                                          : GetVisibilityForFamily(keyName);
+                             families.AppendElement(fontlist::Family::InitData(
+                                 keyName, otherFamilyName,
+                                 fontlist::Family::kNoIndex, visibility,
+                                 /*bundled*/ aAppFont, /*badUnderline*/ false));
+
+                             return MakeUnique<FaceInitArray>();
+                           })
+          ->AppendElement(fontlist::Face::InitData{descriptor, 0, false, weight,
+                                                   stretch, style});
 
       n++;
       if (n == int(cIndex)) {
diff --git a/gfx/thebes/gfxPlatformFontList.cpp b/gfx/thebes/gfxPlatformFontList.cpp
index 269b7519aabc..bc2ed9342f60 100644
--- a/gfx/thebes/gfxPlatformFontList.cpp
+++ b/gfx/thebes/gfxPlatformFontList.cpp
@@ -1588,10 +1588,9 @@ gfxFontEntry* gfxPlatformFontList::FindFontForFamily(
 
 gfxFontEntry* gfxPlatformFontList::GetOrCreateFontEntry(
     fontlist::Face* aFace, const fontlist::Family* aFamily) {
-  return mFontEntries.WithEntryHandle(aFace, [&](auto&& entry) {
-    return entry.OrInsertWith([=] { return CreateFontEntry(aFace, aFamily); })
-        .get();
-  });
+  return mFontEntries
+      .GetOrInsertWith(aFace, [=] { return CreateFontEntry(aFace, aFamily); })
+      .get();
 }
 
 void gfxPlatformFontList::AddOtherFamilyName(
diff --git a/layout/base/PresShell.cpp b/layout/base/PresShell.cpp
index 786bf015ecaf..6d863481b253 100644
--- a/layout/base/PresShell.cpp
+++ b/layout/base/PresShell.cpp
@@ -10551,11 +10551,11 @@ void ReflowCountMgr::Add(const char* aName, nsIFrame* aFrame) {
   NS_ASSERTION(aName != nullptr, "Name shouldn't be null!");
 
   if (mDumpFrameCounts) {
-    auto* const counter = mCounts.WithEntryHandle(aName, [this](auto&& entry) {
-      return entry
-          .OrInsertWith([this] { return MakeUnique<ReflowCounter>(this); })
-          .get();
-    });
+    auto* const counter =
+        mCounts
+            .GetOrInsertWith(aName,
+                             [this] { return MakeUnique<ReflowCounter>(this); })
+            .get();
     counter->Add();
   }
 
@@ -10564,16 +10564,16 @@ void ReflowCountMgr::Add(const char* aName, nsIFrame* aFrame) {
     char key[KEY_BUF_SIZE_FOR_PTR];
     SprintfLiteral(key, "%p", (void*)aFrame);
     auto* const counter =
-        mIndiFrameCounts.WithEntryHandle(key, [&](auto&& entry) {
-          return entry
-              .OrInsertWith([&aName, &aFrame, this]() {
-                auto counter = MakeUnique<IndiReflowCounter>(this);
-                counter->mFrame = aFrame;
-                counter->mName.AssignASCII(aName);
-                return counter;
-              })
-              .get();
-        });
+        mIndiFrameCounts
+            .GetOrInsertWith(key,
+                             [&aName, &aFrame, this]() {
+                               auto counter =
+                                   MakeUnique<IndiReflowCounter>(this);
+                               counter->mFrame = aFrame;
+                               counter->mName.AssignASCII(aName);
+                               return counter;
+                             })
+            .get();
     // this eliminates extra counts from super classes
     if (counter && counter->mName.EqualsASCII(aName)) {
       counter->mCount++;
diff --git a/layout/base/nsCounterManager.cpp b/layout/base/nsCounterManager.cpp
index 0c937d3250d7..295c9ff9b384 100644
--- a/layout/base/nsCounterManager.cpp
+++ b/layout/base/nsCounterManager.cpp
@@ -308,9 +308,9 @@ bool nsCounterManager::AddCounterChanges(nsIFrame* aFrame) {
 
 nsCounterList* nsCounterManager::CounterListFor(nsAtom* aCounterName) {
   MOZ_ASSERT(aCounterName);
-  return mNames.WithEntryHandle(aCounterName, [](auto&& entry) {
-    return entry.OrInsertWith([] { return MakeUnique<nsCounterList>(); }).get();
-  });
+  return mNames
+      .GetOrInsertWith(aCounterName, [] { return MakeUnique<nsCounterList>(); })
+      .get();
 }
 
 void nsCounterManager::RecalcAll() {
diff --git a/layout/base/nsRefreshDriver.cpp b/layout/base/nsRefreshDriver.cpp
index 26e698f88b99..bedd17008d1b 100644
--- a/layout/base/nsRefreshDriver.cpp
+++ b/layout/base/nsRefreshDriver.cpp
@@ -1354,10 +1354,10 @@ bool nsRefreshDriver::AddImageRequest(imgIRequest* aRequest) {
   if (delay == 0) {
     mRequests.PutEntry(aRequest);
   } else {
-    auto* const start = mStartTable.WithEntryHandle(delay, [](auto&& entry) {
-      return entry.OrInsertWith([] { return MakeUnique<ImageStartData>(); })
-          .get();
-    });
+    auto* const start =
+        mStartTable
+            .GetOrInsertWith(delay, [] { return MakeUnique<ImageStartData>(); })
+            .get();
     start->mEntries.PutEntry(aRequest);
   }
 
diff --git a/layout/printing/nsPrintJob.cpp b/layout/printing/nsPrintJob.cpp
index f84c78fd8105..6ef7fcf27a92 100644
--- a/layout/printing/nsPrintJob.cpp
+++ b/layout/printing/nsPrintJob.cpp
@@ -2029,10 +2029,9 @@ void SelectionRangeState::SelectNodesExceptInSubtree(const Position& aStart,
   static constexpr auto kEllipsis = u"\x2026"_ns;
 
   nsINode* root = aStart.mNode->SubtreeRoot();
-  auto& start =
-      mPositions.WithEntryHandle(root, [&](auto&& entry) -> Position& {
-        return entry.OrInsertWith([&] { return Position{root, 0}; });
-      });
+  auto& start = mPositions.GetOrInsertWith(root, [&] {
+    return Position{root, 0};
+  });
 
   bool ellipsizedStart = false;
   if (auto* text = Text::FromNode(aStart.mNode)) {
diff --git a/layout/style/FontFaceSet.cpp b/layout/style/FontFaceSet.cpp
index f2b454c7a02a..64cf3ac4d4e7 100644
--- a/layout/style/FontFaceSet.cpp
+++ b/layout/style/FontFaceSet.cpp
@@ -1279,9 +1279,8 @@ void FontFaceSet::CacheFontLoadability() {
         if (src.mSourceType != gfxFontFaceSrc::eSourceType_URL) {
           continue;
         }
-        mAllowedFontLoads.WithEntryHandle(&src, [&](auto&& entry) {
-          entry.OrInsertWith([&] { return IsFontLoadAllowed(src); });
-        });
+        Unused << mAllowedFontLoads.GetOrInsertWith(
+            &src, [&] { return IsFontLoadAllowed(src); });
       }
     }
   }
diff --git a/layout/style/ImageLoader.cpp b/layout/style/ImageLoader.cpp
index f89a7b45a391..30c9c749dcc1 100644
--- a/layout/style/ImageLoader.cpp
+++ b/layout/style/ImageLoader.cpp
@@ -169,38 +169,37 @@ void ImageLoader::AssociateRequestToFrame(imgIRequest* aRequest,
   }
 
   auto* const frameSet =
-      mRequestToFrameMap.WithEntryHandle(aRequest, [&](auto&& entry) {
-        return entry
-            .OrInsertWith([&] {
-              mDocument->ImageTracker()->Add(aRequest);
+      mRequestToFrameMap
+          .GetOrInsertWith(
+              aRequest,
+              [&] {
+                mDocument->ImageTracker()->Add(aRequest);
 
-              if (auto entry = sImages->Lookup(aRequest)) {
-                DebugOnly<bool> inserted =
-                    entry.Data()->mImageLoaders.EnsureInserted(this);
-                MOZ_ASSERT(inserted);
-              } else {
-                MOZ_ASSERT_UNREACHABLE(
-                    "Shouldn't be associating images not in sImages");
-              }
+                if (auto entry = sImages->Lookup(aRequest)) {
+                  DebugOnly<bool> inserted =
+                      entry.Data()->mImageLoaders.EnsureInserted(this);
+                  MOZ_ASSERT(inserted);
+                } else {
+                  MOZ_ASSERT_UNREACHABLE(
+                      "Shouldn't be associating images not in sImages");
+                }
 
-              if (nsPresContext* presContext = GetPresContext()) {
-                nsLayoutUtils::RegisterImageRequestIfAnimated(
-                    presContext, aRequest, nullptr);
-              }
-              return MakeUnique<FrameSet>();
-            })
-            .get();
-      });
+                if (nsPresContext* presContext = GetPresContext()) {
+                  nsLayoutUtils::RegisterImageRequestIfAnimated(
+                      presContext, aRequest, nullptr);
+                }
+                return MakeUnique<FrameSet>();
+              })
+          .get();
 
   auto* const requestSet =
-      mFrameToRequestMap.WithEntryHandle(aFrame, [=](auto&& entry) {
-        return entry
-            .OrInsertWith([=]() {
-              aFrame->SetHasImageRequest(true);
-              return MakeUnique<RequestSet>();
-            })
-            .get();
-      });
+      mFrameToRequestMap
+          .GetOrInsertWith(aFrame,
+                           [=]() {
+                             aFrame->SetHasImageRequest(true);
+                             return MakeUnique<RequestSet>();
+                           })
+          .get();
 
   // Add frame to the frameSet, and handle any special processing the
   // frame might require.
@@ -441,9 +440,8 @@ already_AddRefed<imgRequestProxy> ImageLoader::LoadImage(
   if (NS_FAILED(rv) || !request) {
     return nullptr;
   }
-  sImages->WithEntryHandle(request, [](auto&& entry) {
-    entry.OrInsertWith([] { return MakeUnique<ImageTableEntry>(); });
-  });
+  sImages->GetOrInsertWith(request,
+                           [] { return MakeUnique<ImageTableEntry>(); });
   return request.forget();
 }
 
diff --git a/layout/style/ShadowParts.cpp b/layout/style/ShadowParts.cpp
index d406b0f13c34..c80ed254dfe3 100644
--- a/layout/style/ShadowParts.cpp
+++ b/layout/style/ShadowParts.cpp
@@ -106,11 +106,10 @@ ShadowParts ShadowParts::Parse(const nsAString& aString) {
       continue;
     }
     nsAtom* second = mapping.second.get();
-    parts.mMappings.WithEntryHandle(mapping.first, [&](auto&& entry) {
-      entry.OrInsertWith([] { return MakeUnique<PartList>(); })
-          ->AppendElement(std::move(mapping.second));
-    });
-    parts.mReverseMappings.GetOrInsert(second) = std::move(mapping.first);
+    parts.mMappings
+        .GetOrInsertWith(mapping.first, [] { return MakeUnique<PartList>(); })
+        ->AppendElement(std::move(mapping.second));
+    parts.mReverseMappings.Put(second, std::move(mapping.first));
   }
 
   return parts;
diff --git a/layout/style/SharedStyleSheetCache.cpp b/layout/style/SharedStyleSheetCache.cpp
index 7c23b92c3ffe..2da7b42e62c1 100644
--- a/layout/style/SharedStyleSheetCache.cpp
+++ b/layout/style/SharedStyleSheetCache.cpp
@@ -573,9 +573,8 @@ void SharedStyleSheetCache::CancelLoadsForLoader(css::Loader& aLoader) {
 
 void SharedStyleSheetCache::RegisterLoader(css::Loader& aLoader) {
   MOZ_ASSERT(aLoader.GetDocument());
-  mLoaderPrincipalRefCnt.WithEntryHandle(
-      aLoader.GetDocument()->NodePrincipal(),
-      [](auto&& entry) { entry.OrInsert(0) += 1; });
+  mLoaderPrincipalRefCnt.GetOrInsert(aLoader.GetDocument()->NodePrincipal(),
+                                     0) += 1;
 }
 
 void SharedStyleSheetCache::UnregisterLoader(css::Loader& aLoader) {
diff --git a/netwerk/dns/ChildDNSService.cpp b/netwerk/dns/ChildDNSService.cpp
index d05fcd8f9a6d..3f3cf051a5f7 100644
--- a/netwerk/dns/ChildDNSService.cpp
+++ b/netwerk/dns/ChildDNSService.cpp
@@ -135,12 +135,11 @@ nsresult ChildDNSService::AsyncResolveInternal(
     nsCString key;
     GetDNSRecordHashKey(hostname, DNSResolverInfo::URL(aResolver), type,
                         aOriginAttributes, flags, originalListenerAddr, key);
-    mPendingRequests.WithEntryHandle(key, [&](auto&& entry) {
-      entry
-          .OrInsertWith(
-              [] { return MakeUnique<nsTArray<RefPtr<DNSRequestSender>>>(); })
-          ->AppendElement(sender);
-    });
+    mPendingRequests
+        .GetOrInsertWith(
+            key,
+            [] { return MakeUnique<nsTArray<RefPtr<DNSRequestSender>>>(); })
+        ->AppendElement(sender);
   }
 
   sender->StartRequest();
diff --git a/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp b/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp
index 1c8bfa22a659..7011ac41434a 100644
--- a/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp
+++ b/toolkit/components/antitracking/TemporaryAccessGrantObserver.cpp
@@ -35,27 +35,24 @@ void TemporaryAccessGrantObserver::Create(PermissionManager* aPM,
   if (!sObservers) {
     sObservers = MakeUnique<ObserversTable>();
   }
-  sObservers->WithEntryHandle(
+  Unused << sObservers->GetOrInsertWith(
       std::make_pair(nsCOMPtr<nsIPrincipal>(aPrincipal), nsCString(aType)),
-      [&](auto&& entry) {
-        entry.OrInsertWith([&]() -> nsITimer* {
-          // Only create a new observer if we don't have a matching
-          // entry in our hashtable.
-          nsCOMPtr<nsITimer> timer;
-          RefPtr<TemporaryAccessGrantObserver> observer =
-              new TemporaryAccessGrantObserver(aPM, aPrincipal, aType);
-          nsresult rv =
-              NS_NewTimerWithObserver(getter_AddRefs(timer), observer,
-                                      24 * 60 * 60 * 1000,  // 24 hours
-                                      nsITimer::TYPE_ONE_SHOT);
+      [&]() -> nsCOMPtr<nsITimer> {
+        // Only create a new observer if we don't have a matching
+        // entry in our hashtable.
+        nsCOMPtr<nsITimer> timer;
+        RefPtr<TemporaryAccessGrantObserver> observer =
+            new TemporaryAccessGrantObserver(aPM, aPrincipal, aType);
+        nsresult rv = NS_NewTimerWithObserver(getter_AddRefs(timer), observer,
+                                              24 * 60 * 60 * 1000,  // 24 hours
+                                              nsITimer::TYPE_ONE_SHOT);
 
-          if (NS_SUCCEEDED(rv)) {
-            observer->SetTimer(timer);
-            return timer;
-          }
-          timer->Cancel();
-          return nullptr;
-        });
+        if (NS_SUCCEEDED(rv)) {
+          observer->SetTimer(timer);
+          return timer;
+        }
+        timer->Cancel();
+        return nullptr;
       });
 }
 
diff --git a/toolkit/xre/UntrustedModulesData.cpp b/toolkit/xre/UntrustedModulesData.cpp
index d3b22a8867f9..606069a0a999 100644
--- a/toolkit/xre/UntrustedModulesData.cpp
+++ b/toolkit/xre/UntrustedModulesData.cpp
@@ -318,8 +318,7 @@ void UntrustedModulesData::AddNewLoads(
       continue;
     }
 
-    mModules.WithEntryHandle(
-        iter.Key(), [&](auto&& addPtr) { addPtr.OrInsert(iter.Data()); });
+    Unused << mModules.GetOrInsert(iter.Key(), iter.Data());
   }
 
   // This constant matches the maximum in Telemetry::CombinedStacks