diff --git a/src/Rules/PHPUnit/MockMethodCallRule.php b/src/Rules/PHPUnit/MockMethodCallRule.php
index 107b4ea..cac776c 100644
--- a/src/Rules/PHPUnit/MockMethodCallRule.php
+++ b/src/Rules/PHPUnit/MockMethodCallRule.php
@@ -56,15 +56,19 @@ public function processNode(Node $node, Scope $scope): array
 				)
 				&& !$type->hasMethod($method)->yes()
 			) {
-				$mockClass = array_filter($type->getObjectClassNames(), static function (string $class): bool {
+				$mockClasses = array_filter($type->getObjectClassNames(), static function (string $class): bool {
 					return $class !== MockObject::class && $class !== Stub::class;
 				});
+				if (count($mockClasses) === 0) {
+					continue;
+				}
 
 				$errors[] = sprintf(
 					'Trying to mock an undefined method %s() on class %s.',
 					$method,
-					implode('&', $mockClass)
+					implode('&', $mockClasses)
 				);
+				continue;
 			}
 
 			$mockedClassObject = $type->getTemplateType(InvocationMocker::class, 'TMockedClass');
diff --git a/tests/Rules/PHPUnit/data/mock-method-call.php b/tests/Rules/PHPUnit/data/mock-method-call.php
index bf0fd05..478fa44 100644
--- a/tests/Rules/PHPUnit/data/mock-method-call.php
+++ b/tests/Rules/PHPUnit/data/mock-method-call.php
@@ -36,6 +36,11 @@ public function testBadMethodOnStub()
 		$this->createStub(Bar::class)->method('doBadThing');
 	}
 
+	public function testMockObject(\PHPUnit\Framework\MockObject\MockObject $mock)
+	{
+		$mock->method('doFoo');
+	}
+
 }
 
 class Bar {