diff --git a/src/testlib/qtestcase.h b/src/testlib/qtestcase.h
index bd65c0ecab3..95a1d9160a6 100644
--- a/src/testlib/qtestcase.h
+++ b/src/testlib/qtestcase.h
@@ -315,16 +315,17 @@ namespace QTest
     template <typename T> // Fallback; for built-in types debug streaming must be possible
     inline typename std::enable_if<!QtPrivate::IsQEnumHelper<T>::Value && !std::is_enum_v<T>, char *>::type toString(const T &t)
     {
+        char *result = nullptr;
 #ifndef QT_NO_DEBUG_STREAM
         if constexpr (QTypeTraits::has_ostream_operator_v<QDebug, T>) {
-            return qstrdup(QDebug::toString(t).toUtf8().constData());
+            result = qstrdup(QDebug::toString(t).toUtf8().constData());
         } else {
             static_assert(!QMetaTypeId2<T>::IsBuiltIn,
                         "Built-in type must implement debug streaming operator "
                         "or provide QTest::toString specialization");
         }
 #endif
-        return nullptr;
+        return result;
     }
 
     template<typename F> // Output QFlags of registered enumerations