diff --git a/src/dbus/qdbusextratypes.h b/src/dbus/qdbusextratypes.h
index c548cbe7bb5..cb63df4f932 100644
--- a/src/dbus/qdbusextratypes.h
+++ b/src/dbus/qdbusextratypes.h
@@ -78,9 +78,8 @@ class Q_DBUS_EXPORT QDBusSignature
     QString m_signature;
 public:
     QDBusSignature() noexcept
-    {
-        m_signature.detach(); // mark non-null (empty signatures are valid)
-    }
+        : m_signature(QLatin1StringView("")) // mark non-null (empty signatures are valid)
+    {}
     // compiler-generated copy/move constructor/assignment operators are ok!
     // compiler-generated destructor is ok!