diff --git a/src/corelib/kernel/qobjectdefs_impl.h b/src/corelib/kernel/qobjectdefs_impl.h
index 959a255389e..46a6eab2538 100644
--- a/src/corelib/kernel/qobjectdefs_impl.h
+++ b/src/corelib/kernel/qobjectdefs_impl.h
@@ -93,7 +93,7 @@ namespace QtPrivate {
     template <typename T>
     struct ApplyReturnValue {
         void *data;
-        ApplyReturnValue(void *data_) : data(data_) {}
+        explicit ApplyReturnValue(void *data_) : data(data_) {}
     };
     template<typename T, typename U>
     void operator,(const T &value, const ApplyReturnValue<U> &container) {