--- a/js/src/jsapi-tests/testThreadingMutex.cpp
+++ b/js/src/jsapi-tests/testThreadingMutex.cpp
@@ -29,22 +29,8 @@ END_TEST(testThreadingLockGuard)
 BEGIN_TEST(testThreadingUnlockGuard)
 {
     js::Mutex mutex(js::mutexid::TestMutex);
     js::LockGuard<js::Mutex> guard(mutex);
     js::UnlockGuard<js::Mutex> unguard(guard);
     return true;
 }
 END_TEST(testThreadingUnlockGuard)
-
-BEGIN_TEST(testThreadingMoveMutex)
-{
-    js::Mutex mutex(js::mutexid::TestMutex);
-    mutex.lock();
-    mutex.unlock();
-
-    js::Mutex another(mozilla::Move(mutex));
-    another.lock();
-    another.unlock();
-
-    return true;
-}
-END_TEST(testThreadingMoveMutex)

--- a/js/src/threading/Mutex.h
+++ b/js/src/threading/Mutex.h
@@ -25,29 +25,16 @@ namespace detail {
 class MutexImpl
 {
 public:
   struct PlatformData;
 
   MutexImpl();
   ~MutexImpl();
 
-  MutexImpl(MutexImpl&& rhs)
-    : platformData_(rhs.platformData_)
-  {
-    MOZ_ASSERT(this != &rhs, "self move disallowed!");
-    rhs.platformData_ = nullptr;
-  }
-
-  MutexImpl& operator=(MutexImpl&& rhs) {
-    this->~MutexImpl();
-    new (this) MutexImpl(mozilla::Move(rhs));
-    return *this;
-  }
-
   bool operator==(const MutexImpl& rhs) {
     return platformData_ == rhs.platformData_;
   }
 
 protected:
   void lock();
   void unlock();