1 files changed, 8 insertions, 6 deletions
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index 790c187cb9..d262e4ebc9 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -156,6 +156,12 @@ namespace QtSharedPointer {
         inline void checkQObjectShared(...) { }
         inline void setQObjectShared(...) { }
 
+        // Normally, only subclasses of ExternalRefCountData are allocated
+        // One exception exists in getAndRef; that uses the global operator new
+        // to prevent a mismatch with the custom operator delete
+        inline void *operator new(std::size_t) = delete;
+        // placement new
+        inline void *operator new(std::size_t, void *ptr) noexcept { return ptr; }
         inline void operator delete(void *ptr) { ::operator delete(ptr); }
         inline void operator delete(void *, void *) { }
     };
@@ -881,7 +887,7 @@ Q_INLINE_TEMPLATE bool operator<(T *ptr1, const QSharedPointer<X> &ptr2)
 template <class T>
 Q_INLINE_TEMPLATE uint qHash(const QSharedPointer<T> &ptr, uint seed = 0)
 {
-    return QT_PREPEND_NAMESPACE(qHash)(ptr.data(), seed);
+    return qHash(ptr.data(), seed);
 }
 
 
@@ -1012,15 +1018,11 @@ std::shared_ptr<X> qobject_pointer_cast(std::shared_ptr<T> &&src)
     using element_type = typename std::shared_ptr<X>::element_type;
     auto castResult = qobject_cast<element_type *>(src.get());
     if (castResult) {
-        auto result = std::shared_ptr<X>(std::move(src), castResult);
-#if __cplusplus <= 201703L
         // C++2a's move aliasing constructor will leave src empty.
         // Before C++2a we don't really know if the compiler has support for it.
         // The move aliasing constructor is the resolution for LWG2996,
         // which does not impose a feature-testing macro. So: clear src.
-        src.reset();
-#endif
-        return result;
+        return std::shared_ptr<X>(qExchange(src, nullptr), castResult);
     }
     return std::shared_ptr<X>();
 }