diff --git a/src/corelib/itemmodels/qgenericitemmodel.h b/src/corelib/itemmodels/qgenericitemmodel.h
index 66ef0bd3956..9f6b01ab66e 100644
--- a/src/corelib/itemmodels/qgenericitemmodel.h
+++ b/src/corelib/itemmodels/qgenericitemmodel.h
@@ -181,7 +181,7 @@ protected:
             return 0;
 
         if constexpr (QGenericItemModelDetails::test_size<C>()) {
-            return std::size(c);
+            return int(std::size(c));
         } else {
 #if defined(__cpp_lib_ranges)
             return int(std::ranges::distance(QGenericItemModelDetails::begin(c),