Adding minimal test to verify EntityManager behavior against #5796

tests/Doctrine/Tests/ORM/EntityManagerTest.php

@@ -232,6 +232,24 @@ class EntityManagerTest extends OrmTestCase
         EntityManager::create(1, $config);
     }
 
+    /**
+     * @group #5796
+     */
+    public function testTransactionalReThrowsThrowables()
+    {
+        try {
+            $this->_em->transactional(function () {
+                (function (array $value) {
+                    // this only serves as an IIFE that throws a `TypeError`
+                })(null);
+            });
+
+            self::fail('TypeError expected to be thrown');
+        } catch (\TypeError $ignored) {
+            self::assertFalse($this->_em->isOpen());
+        }
+    }
+
     /**
      * @group 6017
      */