diff --git a/src/Type/ObjectType.php b/src/Type/ObjectType.php
index 05705fe683..04441d0e03 100644
--- a/src/Type/ObjectType.php
+++ b/src/Type/ObjectType.php
@@ -946,6 +946,10 @@ public function getArraySize(): Type
 			return new ErrorType();
 		}
 
+		if ($this->hasMethod('count')->yes() === false) {
+			return IntegerRangeType::fromInterval(0, null);
+		}
+
 		return RecursionGuard::run($this, fn (): Type => $this->getMethod('count', new OutOfClassScope())->getOnlyVariant()->getReturnType());
 	}
 
diff --git a/tests/PHPStan/Analyser/nsrt/countable.php b/tests/PHPStan/Analyser/nsrt/countable.php
index d2cafc3d4e..1399228135 100644
--- a/tests/PHPStan/Analyser/nsrt/countable.php
+++ b/tests/PHPStan/Analyser/nsrt/countable.php
@@ -30,6 +30,9 @@ static public function doBar() {
 	}
 }
 
+interface Baz {
+}
+
 class NonCountable {}
 
 function doNonCountable() {
@@ -43,3 +46,7 @@ function doFoo() {
 function doBar() {
 	assertType('-1', count(new Bar()));
 }
+
+function doBaz(Baz $baz) {
+	assertType('int<0, max>', count($baz));
+}