diff --git a/src/corelib/io/qabstractfileengine.cpp b/src/corelib/io/qabstractfileengine.cpp
index c9f218ddf5..ea5ce13b5e 100644
--- a/src/corelib/io/qabstractfileengine.cpp
+++ b/src/corelib/io/qabstractfileengine.cpp
@@ -779,10 +779,7 @@ bool QAbstractFileEngine::atEnd() const
 
 uchar *QAbstractFileEngine::map(qint64 offset, qint64 size, QFile::MemoryMapFlags flags)
 {
-    MapExtensionOption option;
-    option.offset = offset;
-    option.size = size;
-    option.flags = flags;
+    const MapExtensionOption option(offset, size, flags);
     MapExtensionReturn r;
     if (!extension(MapExtension, &option, &r))
         return nullptr;
@@ -803,8 +800,7 @@ uchar *QAbstractFileEngine::map(qint64 offset, qint64 size, QFile::MemoryMapFlag
  */
 bool QAbstractFileEngine::unmap(uchar *address)
 {
-    UnMapExtensionOption options;
-    options.address = address;
+    const UnMapExtensionOption options(address);
     return extension(UnMapExtension, &options);
 }
 
diff --git a/src/corelib/io/qabstractfileengine_p.h b/src/corelib/io/qabstractfileengine_p.h
index 903ee1276c..b2e0b248da 100644
--- a/src/corelib/io/qabstractfileengine_p.h
+++ b/src/corelib/io/qabstractfileengine_p.h
@@ -147,19 +147,26 @@ public:
     {};
 
     class MapExtensionOption : public ExtensionOption {
+        Q_DISABLE_COPY_MOVE(MapExtensionOption)
     public:
         qint64 offset;
         qint64 size;
         QFile::MemoryMapFlags flags;
+        constexpr MapExtensionOption(qint64 off, qint64 sz, QFile::MemoryMapFlags f)
+            : offset(off), size(sz), flags(f) {}
     };
     class MapExtensionReturn : public ExtensionReturn {
+        Q_DISABLE_COPY_MOVE(MapExtensionReturn)
     public:
-        uchar *address;
+        MapExtensionReturn() = default;
+        uchar *address = nullptr;
     };
 
     class UnMapExtensionOption : public ExtensionOption {
+        Q_DISABLE_COPY_MOVE(UnMapExtensionOption)
     public:
-        uchar *address;
+        uchar *address = nullptr;
+        constexpr UnMapExtensionOption(uchar *p) : address(p) {}
     };
 
     virtual bool extension(Extension extension, const ExtensionOption *option = nullptr, ExtensionReturn *output = nullptr);