code: def _validate_field_can_be_tagged_with_redactor(self, field):
          
          if is_alias(field.data_type):
              raise InvalidSpec(
                  "Redactors can only be applied to alias definitions, not "
                  "to alias references.",
                  field._ast_node.lineno, field._ast_node.path)
  
          self._validate_object_can_be_tagged_with_redactor(field)
docs: Validates that the field type can be annotated and that alias does not have
          conflicting annotations.