code: private function getFileAst(\ReflectionFunction $reflection)
      {
          $fileName = $reflection->getFileName();
          if (!file_exists($fileName)) {
              throw new ClosureAnalysisException(
                  "The file containing the closure, \"{$fileName}\" did not exist."
              );
          }
  
  
          return $this->getParser()->parse(file_get_contents($fileName));
      }
docs: @param \ReflectionFunction $reflection
  
  @throws ClosureAnalysisException
  
  @return \PhpParser\Node[]