diff --git a/packages/NodeTypeResolver/TypeAnalyzer/CountableTypeAnalyzer.php b/packages/NodeTypeResolver/TypeAnalyzer/CountableTypeAnalyzer.php
index 0717d2d95b1e..a6a7e77c9dc8 100644
--- a/packages/NodeTypeResolver/TypeAnalyzer/CountableTypeAnalyzer.php
+++ b/packages/NodeTypeResolver/TypeAnalyzer/CountableTypeAnalyzer.php
@@ -65,7 +65,7 @@ private function isCountableObjectType(Type $type): bool
 
         if ($type instanceof ObjectType) {
             foreach ($countableObjectTypes as $countableObjectType) {
-                if (! is_a($type->getClassName(), $countableObjectType->getClassName(), true)) {
+                if ($countableObjectType->isSuperTypeOf($type)->no()) {
                     continue;
                 }