code: public function setSourceContext(Twig_Source $source = null)
      {
          if (null === $source) {
              $this->sourceCode = $this->filename = $this->sourcePath = null;
          } else {
              $this->sourceCode = $source->getCode();
              $this->filename = $source->getName();
              $this->sourcePath = $source->getPath();
          }
  
          $this->updateRepr();
      }
docs: Sets the source context of the Twig template where the error occurred.