code: func isInJSONContext(exp criteria.Expression) bool {
  	result := false
  	criteria.IterateParents(exp, func(exp criteria.Expression) bool {
  		if exp.Annotation(jsonAnnotation) == true {
  			result = true
  			return false
  		}
  		return true
  	})
  	return result
  }
docs: // iterate the parent chain to see if this expression references json fields