Merge branch '2.3' into 2.7

* 2.3:
  [Process] Unset callback after stop to free memory
  Improve error message for undefined DIC aliases
  Fix typo
  CS: remove unneeded parentheses around control statements

Author: stof

Parser.php

@@ -707,6 +707,6 @@ private function isNextLineUnIndentedCollection()
      */
     private function isStringUnIndentedCollectionItem()
     {
-        return (0 === strpos($this->currentLine, '- '));
+        return 0 === strpos($this->currentLine, '- ');
     }
 }