Fix getting a property on an object casted to an array

src/Extension/CoreExtension.php

@@ -1673,7 +1673,7 @@ final class CoreExtension extends AbstractExtension
                     $env->getExtension(SandboxExtension::class)->checkPropertyAllowed($object, $item, $lineno, $source);
                 }
 
-                return $object->$item;
+                return isset($object->$item) ? $object->$item : ((array) $object)[(string) $item];
             }
         }
 

tests/Fixtures/expressions/attributes.test

@@ -0,0 +1,13 @@
+--TEST--
+"." notation
+--TEMPLATE--
+{{ property.foo }}
+{{ date.timezone }}
+--DATA--
+return [
+    'date' => new \DateTimeImmutable('now', new \DateTimeZone('Europe/Paris')),
+    'property' => (object) array('foo' => 'bar'),
+]
+--EXPECT--
+bar
+Europe/Paris