Fixed usage of LimitIterator

lib/Twig/Extension/Core.php

@@ -697,7 +697,7 @@ function twig_slice(Twig_Environment $env, $item, $start, $length = null, $prese
         }
 
         if ($start >= 0 && $length >= 0) {
-            return iterator_to_array(new LimitIterator($item, $start, $length), $preserveKeys);
+            return iterator_to_array(new LimitIterator($item, $start, $length === null ? -1 : $length), $preserveKeys);
         }
 
         $item = iterator_to_array($item, $preserveKeys);

test/Twig/Tests/Fixtures/filters/slice.test

@@ -19,6 +19,9 @@
 {{ '1234'|slice(1) }}
 {{ '1234'[1:] }}
 {{ '1234'[:1] }}
+
+{{ arr|slice(3)|join('') }}
+{{ arr[2:]|join('') }}
 --DATA--
 return array('start' => 1, 'length' => 2, 'arr' => new ArrayObject(array(1, 2, 3, 4)))
 --EXPECT--
@@ -40,3 +43,6 @@ bc
 234
 234
 1
+
+4
+34