--- a/xpcom/glue/nsISupportsImpl.h
+++ b/xpcom/glue/nsISupportsImpl.h
@@ -166,16 +166,19 @@ class nsCycleCollectingAutoRefCnt
 public:
   nsCycleCollectingAutoRefCnt() : mRefCntAndFlags(0) {}
 
   explicit nsCycleCollectingAutoRefCnt(uintptr_t aValue)
     : mRefCntAndFlags(aValue << NS_NUMBER_OF_FLAGS_IN_REFCNT)
   {
   }
 
+  nsCycleCollectingAutoRefCnt(const nsCycleCollectingAutoRefCnt&) = delete;
+  void operator=(const nsCycleCollectingAutoRefCnt&) = delete;
+
   MOZ_ALWAYS_INLINE uintptr_t incr(nsISupports* aOwner)
   {
     return incr(aOwner, nullptr);
   }
 
   MOZ_ALWAYS_INLINE uintptr_t incr(void* aOwner,
                                    nsCycleCollectionParticipant* aCp)
   {
@@ -260,16 +263,19 @@ private:
 };
 
 class nsAutoRefCnt
 {
 public:
   nsAutoRefCnt() : mValue(0) {}
   explicit nsAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {}
 
+  nsAutoRefCnt(const nsAutoRefCnt&) = delete;
+  void operator=(const nsAutoRefCnt&) = delete;
+
   // only support prefix increment/decrement
   nsrefcnt operator++() { return ++mValue; }
   nsrefcnt operator--() { return --mValue; }
 
   nsrefcnt operator=(nsrefcnt aValue) { return (mValue = aValue); }
   operator nsrefcnt() const { return mValue; }
   nsrefcnt get() const { return mValue; }
 
@@ -282,16 +288,19 @@ private:
 
 namespace mozilla {
 class ThreadSafeAutoRefCnt
 {
 public:
   ThreadSafeAutoRefCnt() : mValue(0) {}
   explicit ThreadSafeAutoRefCnt(nsrefcnt aValue) : mValue(aValue) {}
 
+  ThreadSafeAutoRefCnt(const ThreadSafeAutoRefCnt&) = delete;
+  void operator=(const ThreadSafeAutoRefCnt&) = delete;
+
   // only support prefix increment/decrement
   MOZ_ALWAYS_INLINE nsrefcnt operator++() { return ++mValue; }
   MOZ_ALWAYS_INLINE nsrefcnt operator--() { return --mValue; }
 
   MOZ_ALWAYS_INLINE nsrefcnt operator=(nsrefcnt aValue)
   {
     return (mValue = aValue);
   }