Bug 1237151 (part 3) - Remove ignored qualifiers in all remaining code. r=froydnj.

docshell/base/timeline/AbstractTimelineMarker.h

@@ -49,8 +49,8 @@ public:
   DOMHighResTimeStamp GetTime() const { return mTime; }
   MarkerTracingType GetTracingType() const { return mTracingType; }
 
-  const uint8_t GetProcessType() const { return mProcessType; };
-  const bool IsOffMainThread() const { return mIsOffMainThread; };
+  uint8_t GetProcessType() const { return mProcessType; };
+  bool IsOffMainThread() const { return mIsOffMainThread; };
 
 private:
   const char* mName;

dom/gamepad/cocoa/CocoaGamepad.cpp

@@ -93,7 +93,7 @@ class Gamepad {
   // Index given by our superclass.
   uint32_t mSuperIndex;
 
-  const bool isDpad(IOHIDElementRef element) const
+  bool isDpad(IOHIDElementRef element) const
   {
     return element == mDpad;
   }

dom/inputport/InputPortData.cpp

@@ -103,7 +103,7 @@ InputPortData::GetId() const
   return mId;
 }
 
-const InputPortType
+InputPortType
 InputPortData::GetType() const
 {
   return ToInputPortType(mType);

dom/inputport/InputPortData.h

@@ -33,7 +33,7 @@ public:
 
   const nsString& GetId() const;
 
-  const InputPortType GetType() const;
+  InputPortType GetType() const;
 
 private:
   ~InputPortData();

dom/media/android/AndroidMediaDecoder.h

@@ -17,7 +17,7 @@ class AndroidMediaDecoder : public MediaDecoder
 public:
   AndroidMediaDecoder(MediaDecoderOwner* aOwner, const nsACString& aType);
 
-  const nsresult GetContentType(nsACString& aType) const {
+  nsresult GetContentType(nsACString& aType) const {
     aType = mType;
     return NS_OK;
   }

dom/media/omx/OMXCodecWrapper.cpp

@@ -805,7 +805,7 @@ public:
 private:
   uint8_t* GetPointer() { return mData + mOffset; }
 
-  const size_t AvailableSize() { return mCapicity - mOffset; }
+  size_t AvailableSize() const { return mCapicity - mOffset; }
 
   void IncreaseOffset(size_t aValue)
   {
@@ -814,12 +814,12 @@ private:
     mOffset += aValue;
   }
 
-  bool IsEmpty()
+  bool IsEmpty() const
   {
     return (mOffset == 0);
   }
 
-  const size_t GetCapacity()
+  size_t GetCapacity() const
   {
     return mCapicity;
   }

dom/notification/Notification.h

@@ -344,7 +344,7 @@ protected:
     }
   }
 
-  static const NotificationDirection StringToDirection(const nsAString& aDirection)
+  static NotificationDirection StringToDirection(const nsAString& aDirection)
   {
     if (aDirection.EqualsLiteral("ltr")) {
       return NotificationDirection::Ltr;

dom/plugins/ipc/PluginMessageUtils.h

@@ -120,7 +120,7 @@ typedef mozilla::null_t DXGISharedSurfaceHandle;
 // XXX maybe not the best place for these. better one?
 
 #define VARSTR(v_)  case v_: return #v_
-inline const char* const
+inline const char*
 NPPVariableToString(NPPVariable aVar)
 {
     switch (aVar) {

dom/presentation/provider/MulticastDNSDeviceProvider.h

@@ -86,12 +86,12 @@ private:
       return mAddress;
     }
 
-    const uint16_t Port() const
+    uint16_t Port() const
     {
       return mPort;
     }
 
-    const DeviceState State() const
+    DeviceState State() const
     {
       return mState;
     }

dom/smil/nsSMILCSSValueType.cpp

@@ -72,7 +72,7 @@ GetZeroValueForUnit(StyleAnimationValue::Unit aUnit)
 // with a eUnit_Float value.  (See comment below.)
 //
 // Returns true on success, or false.
-static const bool
+static bool
 FinalizeStyleAnimationValues(const StyleAnimationValue*& aValue1,
                              const StyleAnimationValue*& aValue2)
 {

dom/svg/SVGTransform.h

@@ -134,7 +134,7 @@ protected:
 
   // Interface for SVGMatrix's use
   friend class dom::SVGMatrix;
-  const bool IsAnimVal() const {
+  bool IsAnimVal() const {
     return mIsAnimValItem;
   }
   const gfxMatrix& Matrixgfx() const {

embedding/components/printingui/unixshared/nsPrintingPromptService.cpp

@@ -43,7 +43,7 @@ public:
       return CallCreateInstance(NS_DIALOGPARAMBLOCK_CONTRACTID, &mBlock);
     }
     nsIDialogParamBlock * operator->() const MOZ_NO_ADDREF_RELEASE_ON_RETURN { return mBlock; }
-    operator nsIDialogParamBlock * const ()  { return mBlock; }
+    operator nsIDialogParamBlock * () const { return mBlock; }
 
 private:
     nsIDialogParamBlock *mBlock;

gfx/layers/Layers.cpp

@@ -941,7 +941,7 @@ Layer::ApplyPendingUpdatesForThisTransaction()
   }
 }
 
-const float
+float
 Layer::GetLocalOpacity()
 {
   float opacity = mOpacity;

gfx/layers/Layers.h

@@ -1354,7 +1354,7 @@ public:
    * Returns the local opacity for this layer: either mOpacity or,
    * for shadow layers, GetShadowOpacity()
    */
-  const float GetLocalOpacity();
+  float GetLocalOpacity();
 
   /**
    * DRAWING PHASE ONLY
@@ -1637,7 +1637,7 @@ public:
    * marked as needed to be recomposited.
    */
   const nsIntRegion& GetInvalidRegion() { return mInvalidRegion; }
-  const void AddInvalidRegion(const nsIntRegion& aRegion) {
+  void AddInvalidRegion(const nsIntRegion& aRegion) {
     mInvalidRegion.Or(mInvalidRegion, aRegion);
   }
 

gfx/thebes/gfxUtils.cpp

@@ -92,11 +92,11 @@ void mozilla_dump_image(void* bytes, int width, int height, int bytepp,
 
 }
 
-static const uint8_t PremultiplyValue(uint8_t a, uint8_t v) {
+static uint8_t PremultiplyValue(uint8_t a, uint8_t v) {
     return gfxUtils::sPremultiplyTable[a*256+v];
 }
 
-static const uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) {
+static uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) {
     return gfxUtils::sUnpremultiplyTable[a*256+v];
 }
 

ipc/chromium/src/chrome/common/ipc_message.h

@@ -194,7 +194,7 @@ class Message : public Pickle {
     header()->seqno = aSeqno;
   }
 
-  const char* const name() const {
+  const char* name() const {
     return name_;
   }
 

ipc/chromium/src/chrome/common/ipc_message_utils.h

@@ -53,7 +53,7 @@ class MessageIterator {
       NOTREACHED();
     return val;
   }
-  const void NextData(const char** data, int* length) const {
+  void NextData(const char** data, int* length) const {
     if (!msg_.ReadData(&iter_, data, length)) {
       NOTREACHED();
     }

ipc/ipdl/ipdl/lower.py

@@ -577,7 +577,7 @@ def _cxxConstPtrToType(ipdltype, side):
         t.ptrconstptr = 1
         return t
     t.const = 1
-    t.ptrconst = 1
+    t.ptr = 1
     return t
 
 def _allocMethod(ptype, side):

layout/base/nsPresContext.h

@@ -403,18 +403,18 @@ public:
   /**
    * Get the default colors
    */
-  const nscolor DefaultColor() const { return mDefaultColor; }
-  const nscolor DefaultBackgroundColor() const { return mBackgroundColor; }
-  const nscolor DefaultLinkColor() const { return mLinkColor; }
-  const nscolor DefaultActiveLinkColor() const { return mActiveLinkColor; }
-  const nscolor DefaultVisitedLinkColor() const { return mVisitedLinkColor; }
-  const nscolor FocusBackgroundColor() const { return mFocusBackgroundColor; }
-  const nscolor FocusTextColor() const { return mFocusTextColor; }
+  nscolor DefaultColor() const { return mDefaultColor; }
+  nscolor DefaultBackgroundColor() const { return mBackgroundColor; }
+  nscolor DefaultLinkColor() const { return mLinkColor; }
+  nscolor DefaultActiveLinkColor() const { return mActiveLinkColor; }
+  nscolor DefaultVisitedLinkColor() const { return mVisitedLinkColor; }
+  nscolor FocusBackgroundColor() const { return mFocusBackgroundColor; }
+  nscolor FocusTextColor() const { return mFocusTextColor; }
 
   /**
    * Body text color, for use in quirks mode only.
    */
-  const nscolor BodyTextColor() const { return mBodyTextColor; }
+  nscolor BodyTextColor() const { return mBodyTextColor; }
   void SetBodyTextColor(nscolor aColor) { mBodyTextColor = aColor; }
 
   bool GetUseFocusColors() const { return mUseFocusColors; }

layout/generic/nsGridContainerFrame.cpp

@@ -321,7 +321,7 @@ private:
   }
 
   // Return true if aName exists at aIndex.
-  const bool Contains(uint32_t aIndex, const nsString& aName) const
+  bool Contains(uint32_t aIndex, const nsString& aName) const
   {
     if (!mHasRepeatAuto) {
       return mLineNameLists[aIndex].Contains(aName);

mozglue/linker/Mappable.h

@@ -239,18 +239,18 @@ private:
     }
 
     /* Returns offset + length */
-    const off_t endOffset() const {
+    off_t endOffset() const {
       return offset + length;
     }
 
     /* Returns the offset corresponding to the given address */
-    const off_t offsetOf(const void *ptr) const {
+    off_t offsetOf(const void *ptr) const {
       return reinterpret_cast<uintptr_t>(ptr)
              - reinterpret_cast<uintptr_t>(addr) + offset;
     }
 
     /* Returns whether the given address is in the LazyMap range */
-    const bool Contains(const void *ptr) const {
+    bool Contains(const void *ptr) const {
       return (ptr >= addr) && (ptr < end());
     }
   };

mozglue/linker/SeekableZStream.h

@@ -77,18 +77,18 @@ public:
   bool DecompressChunk(void *where, size_t chunk, size_t length = 0);
  
   /* Returns the uncompressed size of the complete zstream */
-  const size_t GetUncompressedSize() const
+  size_t GetUncompressedSize() const
   {
     return (offsetTable.numElements() - 1) * chunkSize + lastChunkSize;
   }
 
   /* Returns the chunk size of the given chunk */
-  const size_t GetChunkSize(size_t chunk = 0) const {
+  size_t GetChunkSize(size_t chunk = 0) const {
     return (chunk == offsetTable.numElements() - 1) ? lastChunkSize : chunkSize;
   }
 
   /* Returns the number of chunks */
-  const size_t GetChunksNum() const {
+  size_t GetChunksNum() const {
     return offsetTable.numElements();
   }
 

netwerk/cache2/CacheObserver.cpp

@@ -240,7 +240,7 @@ CacheObserver::AttachToPreferences()
 }
 
 // static
-uint32_t const CacheObserver::MemoryCacheCapacity()
+uint32_t CacheObserver::MemoryCacheCapacity()
 {
   if (sMemoryCacheCapacity >= 0)
     return sMemoryCacheCapacity << 10;
@@ -278,7 +278,7 @@ uint32_t const CacheObserver::MemoryCacheCapacity()
 }
 
 // static
-bool const CacheObserver::UseNewCache()
+bool CacheObserver::UseNewCache()
 {
   uint32_t useNewCache = sUseNewCache;
 
@@ -441,7 +441,7 @@ nsresult Run(NeckoOriginAttributes const &aOa)
 } // anon
 
 // static
-bool const CacheObserver::EntryIsTooBig(int64_t aSize, bool aUsingDisk)
+bool CacheObserver::EntryIsTooBig(int64_t aSize, bool aUsingDisk)
 {
   // If custom limit is set, check it.
   int64_t preferredLimit = aUsingDisk ? sMaxDiskEntrySize : sMaxMemoryEntrySize;

netwerk/cache2/CacheObserver.h

@@ -27,49 +27,49 @@ class CacheObserver : public nsIObserver
   static CacheObserver* Self() { return sSelf; }
 
   // Access to preferences
-  static bool const UseNewCache();
-  static bool const UseDiskCache()
+  static bool UseNewCache();
+  static bool UseDiskCache()
     { return sUseDiskCache; }
-  static bool const UseMemoryCache()
+  static bool UseMemoryCache()
     { return sUseMemoryCache; }
-  static uint32_t const MetadataMemoryLimit() // result in bytes.
+  static uint32_t MetadataMemoryLimit() // result in bytes.
     { return sMetadataMemoryLimit << 10; }
-  static uint32_t const MemoryCacheCapacity(); // result in bytes.
-  static uint32_t const DiskCacheCapacity() // result in bytes.
+  static uint32_t MemoryCacheCapacity(); // result in bytes.
+  static uint32_t DiskCacheCapacity() // result in bytes.
     { return sDiskCacheCapacity << 10; }
   static void SetDiskCacheCapacity(uint32_t); // parameter in bytes.
-  static uint32_t const DiskFreeSpaceSoftLimit() // result in bytes.
+  static uint32_t DiskFreeSpaceSoftLimit() // result in bytes.
     { return sDiskFreeSpaceSoftLimit << 10; }
-  static uint32_t const DiskFreeSpaceHardLimit() // result in bytes.
+  static uint32_t DiskFreeSpaceHardLimit() // result in bytes.
     { return sDiskFreeSpaceHardLimit << 10; }
-  static bool const SmartCacheSizeEnabled()
+  static bool SmartCacheSizeEnabled()
     { return sSmartCacheSizeEnabled; }
-  static uint32_t const PreloadChunkCount()
+  static uint32_t PreloadChunkCount()
     { return sPreloadChunkCount; }
-  static uint32_t const MaxMemoryEntrySize() // result in bytes.
+  static uint32_t MaxMemoryEntrySize() // result in bytes.
     { return sMaxMemoryEntrySize << 10; }
-  static uint32_t const MaxDiskEntrySize() // result in bytes.
+  static uint32_t MaxDiskEntrySize() // result in bytes.
     { return sMaxDiskEntrySize << 10; }
-  static uint32_t const MaxDiskChunksMemoryUsage(bool aPriority) // result in bytes.
+  static uint32_t MaxDiskChunksMemoryUsage(bool aPriority) // result in bytes.
     { return aPriority ? sMaxDiskPriorityChunksMemoryUsage << 10
                        : sMaxDiskChunksMemoryUsage << 10; }
-  static uint32_t const CompressionLevel()
+  static uint32_t CompressionLevel()
     { return sCompressionLevel; }
-  static uint32_t const HalfLifeSeconds()
+  static uint32_t HalfLifeSeconds()
     { return sHalfLifeHours * 60.0F * 60.0F; }
-  static int32_t const HalfLifeExperiment()
+  static int32_t HalfLifeExperiment()
     { return sHalfLifeExperiment; }
-  static bool const ClearCacheOnShutdown()
+  static bool ClearCacheOnShutdown()
     { return sSanitizeOnShutdown && sClearCacheOnShutdown; }
-  static bool const CacheFSReported()
+  static bool CacheFSReported()
     { return sCacheFSReported; }
   static void SetCacheFSReported();
-  static bool const HashStatsReported()
+  static bool HashStatsReported()
     { return sHashStatsReported; }
   static void SetHashStatsReported();
   static void ParentDirOverride(nsIFile ** aDir);
 
-  static bool const EntryIsTooBig(int64_t aSize, bool aUsingDisk);
+  static bool EntryIsTooBig(int64_t aSize, bool aUsingDisk);
 
 private:
   static CacheObserver* sSelf;

netwerk/cache2/CacheStorageService.cpp

@@ -88,7 +88,7 @@ CacheStorageService::MemoryPool::~MemoryPool()
   }
 }
 
-uint32_t const
+uint32_t
 CacheStorageService::MemoryPool::Limit() const
 {
   switch (mType) {

netwerk/cache2/CacheStorageService.h

@@ -324,7 +324,7 @@ private:
     void PurgeAll(uint32_t aWhat);
 
   private:
-    uint32_t const Limit() const;
+    uint32_t Limit() const;
     MemoryPool() = delete;
   };
 

parser/htmlparser/nsParser.cpp

@@ -1684,7 +1684,7 @@ ExtractCharsetFromXmlDeclaration(const unsigned char* aBytes, int32_t aLen,
   return !oCharset.IsEmpty();
 }
 
-inline const char
+inline char
 GetNextChar(nsACString::const_iterator& aStart,
             nsACString::const_iterator& aEnd)
 {

storage/mozStorageBindingParamsArray.h

@@ -46,7 +46,7 @@ public:
   /**
    * @return the number of elemets the array contains.
    */
-  const size_type length() const { return mArray.Length(); }
+  size_type length() const { return mArray.Length(); }
 
   class iterator {
   public:

toolkit/components/osfile/NativeOSFileInternals.cpp

@@ -84,7 +84,7 @@ struct ScopedArrayBufferContentsTraits {
     type result = {0, 0};
     return result;
   }
-  const static void release(type ptr) {
+  static void release(type ptr) {
     js_free(ptr.data);
     ptr.data = nullptr;
     ptr.nbytes = 0;

toolkit/mozapps/update/updater/automounter_gonk.h

@@ -27,7 +27,7 @@ public:
   GonkAutoMounter();
   ~GonkAutoMounter();
 
-  const MountAccess GetAccess()
+  MountAccess GetAccess() const
   {
     return mAccess;
   }

tools/profiler/lul/LulCommon.cpp

@@ -77,7 +77,7 @@ class UniqueString {
   const char* str_;
 };
 
-const char* const FromUniqueString(const UniqueString* ustr)
+const char* FromUniqueString(const UniqueString* ustr)
 {
   return ustr->str_;
 }

tools/profiler/lul/LulCommonExt.h

@@ -85,7 +85,7 @@ using std::map;
 class UniqueString;
 
 // Get the contained C string (debugging only)
-const char* const FromUniqueString(const UniqueString*);
+const char* FromUniqueString(const UniqueString*);
 
 // Is the given string empty (that is, "") ?
 bool IsEmptyUniqueString(const UniqueString*);

tools/profiler/lul/LulDwarf.cpp

@@ -1803,7 +1803,7 @@ void CallFrameInfo::Reporter::ClearingCFARule(uint64 offset,
 }
 
 
-const unsigned int DwarfCFIToModule::RegisterNames::I386() {
+unsigned int DwarfCFIToModule::RegisterNames::I386() {
   /*
    8 "$eax", "$ecx", "$edx", "$ebx", "$esp", "$ebp", "$esi", "$edi",
    3 "$eip", "$eflags", "$unused1",
@@ -1818,7 +1818,7 @@ const unsigned int DwarfCFIToModule::RegisterNames::I386() {
   return 8 + 3 + 8 + 2 + 8 + 8 + 3 + 8 + 2;
 }
 
-const unsigned int DwarfCFIToModule::RegisterNames::X86_64() {
+unsigned int DwarfCFIToModule::RegisterNames::X86_64() {
   /*
    8 "$rax", "$rdx", "$rcx", "$rbx", "$rsi", "$rdi", "$rbp", "$rsp",
    8 "$r8",  "$r9",  "$r10", "$r11", "$r12", "$r13", "$r14", "$r15",
@@ -1837,7 +1837,7 @@ const unsigned int DwarfCFIToModule::RegisterNames::X86_64() {
 }
 
 // Per ARM IHI 0040A, section 3.1
-const unsigned int DwarfCFIToModule::RegisterNames::ARM() {
+unsigned int DwarfCFIToModule::RegisterNames::ARM() {
   /*
    8 "r0",  "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
    8 "r8",  "r9",  "r10", "r11", "r12", "sp",  "lr",  "pc",

tools/profiler/lul/LulDwarfExt.h

@@ -1203,13 +1203,13 @@ class DwarfCFIToModule: public CallFrameInfo::Handler {
   class RegisterNames {
    public:
     // Intel's "x86" or IA-32.
-    static const unsigned int I386();
+    static unsigned int I386();
 
     // AMD x86_64, AMD64, Intel EM64T, or Intel 64
-    static const unsigned int X86_64();
+    static unsigned int X86_64();
 
     // ARM.
-    static const unsigned int ARM();
+    static unsigned int ARM();
   };
 
   // Create a handler for the dwarf2reader::CallFrameInfo parser that

widget/gtk/nsPrintDialogGTK.cpp

@@ -116,7 +116,7 @@ class nsPrintDialogWidgetGTK {
     nsPrintDialogWidgetGTK(nsIDOMWindow *aParent, nsIPrintSettings *aPrintSettings);
     ~nsPrintDialogWidgetGTK() { gtk_widget_destroy(dialog); }
     NS_ConvertUTF16toUTF8 GetUTF8FromBundle(const char* aKey);
-    const gint Run();
+    gint Run();
 
     nsresult ImportSettings(nsIPrintSettings *aNSSettings);
     nsresult ExportSettings(nsIPrintSettings *aNSSettings);
@@ -343,7 +343,7 @@ nsPrintDialogWidgetGTK::OptionWidgetToString(GtkWidget *dropdown)
     return header_footer_tags[index];
 }
 
-const gint
+gint
 nsPrintDialogWidgetGTK::Run()
 {
   const gint response = gtk_dialog_run(GTK_DIALOG(dialog));

xpcom/build/PoisonIOInterposerBase.cpp

@@ -38,8 +38,9 @@ namespace {
 struct DebugFilesAutoLockTraits
 {
   typedef PRLock* type;
-  const static type empty() { return nullptr; }
-  const static void release(type aL) { PR_Unlock(aL); }
+  typedef const PRLock* const_type;
+  static const_type empty() { return nullptr; }
+  static void release(type aL) { PR_Unlock(aL); }
 };
 
 class DebugFilesAutoLock : public Scoped<DebugFilesAutoLockTraits>

xpcom/ds/nsIAtom.idl

@@ -16,7 +16,7 @@
  * pointer identity.
  */
  
-[scriptable, builtinclass, uuid(1f341018-521a-49de-b806-1bef5c9a00b0)]
+[scriptable, builtinclass, uuid(8b8c11d4-3ed5-4079-8974-73c7576cdb34)]
 interface nsIAtom : nsISupports
 {
   /**
@@ -48,7 +48,7 @@ interface nsIAtom : nsISupports
     return mString;
   }
 
-  inline const uint32_t GetLength() const {
+  inline uint32_t GetLength() const {
     return mLength;
   }
 

xpcom/glue/PLDHashTable.h

@@ -305,7 +305,7 @@ public:
   ~PLDHashTable();
 
   // This should be used rarely.
-  const PLDHashTableOps* const Ops() { return mOps; }
+  const PLDHashTableOps* Ops() const { return mOps; }
 
   // Size in entries (gross, not net of free and removed sentinels) for table.
   // This can be zero if no elements have been added yet, in which case the

xpcom/glue/nsTArray.h

@@ -260,6 +260,7 @@ template<class E, class Derived>
 struct nsTArray_SafeElementAtHelper<E*, Derived>
 {
   typedef E*       elem_type;
+  //typedef const E* const_elem_type;   XXX: see below
   typedef size_t   index_type;
 
   elem_type SafeElementAt(index_type aIndex)
@@ -267,7 +268,11 @@ struct nsTArray_SafeElementAtHelper<E*, Derived>
     return static_cast<Derived*>(this)->SafeElementAt(aIndex, nullptr);
   }
 
-  const elem_type SafeElementAt(index_type aIndex) const
+  // XXX: Probably should return const_elem_type, but callsites must be fixed.
+  // Also, the use of const_elem_type for nsTArray<xpcGCCallback> in
+  // xpcprivate.h causes build failures on Windows because xpcGCCallback is a
+  // function pointer and MSVC doesn't like qualifying it with |const|.
+  elem_type SafeElementAt(index_type aIndex) const
   {
     return static_cast<const Derived*>(this)->SafeElementAt(aIndex, nullptr);
   }
@@ -279,6 +284,7 @@ template<class E, class Derived>
 struct nsTArray_SafeElementAtSmartPtrHelper
 {
   typedef E*       elem_type;
+  typedef const E* const_elem_type;
   typedef size_t   index_type;
 
   elem_type SafeElementAt(index_type aIndex)
@@ -286,7 +292,8 @@ struct nsTArray_SafeElementAtSmartPtrHelper
     return static_cast<Derived*>(this)->SafeElementAt(aIndex, nullptr);
   }
 
-  const elem_type SafeElementAt(index_type aIndex) const
+  // XXX: Probably should return const_elem_type, but callsites must be fixed.
+  elem_type SafeElementAt(index_type aIndex) const
   {
     return static_cast<const Derived*>(this)->SafeElementAt(aIndex, nullptr);
   }
@@ -313,8 +320,9 @@ template<class T> class OwningNonNull;
 template<class E, class Derived>
 struct nsTArray_SafeElementAtHelper<mozilla::OwningNonNull<E>, Derived>
 {
-  typedef E*     elem_type;
-  typedef size_t index_type;
+  typedef E*       elem_type;
+  typedef const E* const_elem_type;
+  typedef size_t   index_type;
 
   elem_type SafeElementAt(index_type aIndex)
   {
@@ -324,7 +332,8 @@ struct nsTArray_SafeElementAtHelper<mozilla::OwningNonNull<E>, Derived>
     return nullptr;
   }
 
-  const elem_type SafeElementAt(index_type aIndex) const
+  // XXX: Probably should return const_elem_type, but callsites must be fixed.
+  elem_type SafeElementAt(index_type aIndex) const
   {
     if (aIndex < static_cast<const Derived*>(this)->Length()) {
       return static_cast<const Derived*>(this)->ElementAt(aIndex);