diff --git a/src/corelib/tools/qarraydataops.h b/src/corelib/tools/qarraydataops.h
index 5f43ed3dc0d..cf054a089fd 100644
--- a/src/corelib/tools/qarraydataops.h
+++ b/src/corelib/tools/qarraydataops.h
@@ -397,8 +397,8 @@ public:
         T *begin;
         qsizetype size;
 
-        qsizetype sourceCopyConstruct, nSource, move, sourceCopyAssign;
-        T *end, *last, *where;
+        qsizetype sourceCopyConstruct = 0, nSource = 0, move = 0, sourceCopyAssign = 0;
+        T *end = nullptr, *last = nullptr, *where = nullptr;
 
         Inserter(QArrayDataPointer<T> *d, QArrayData::GrowthPosition pos)
             : data(d), increment(pos == QArrayData::GrowsAtBeginning ? -1 : 1)
@@ -414,6 +414,7 @@ public:
             data->ptr = begin;
             data->size = size;
         }
+        Q_DISABLE_COPY(Inserter)
 
         void setup(qsizetype pos, qsizetype n)
         {