Warning about unparseable C++ cross-reference when

[arwedus]

When I parse a function that's including a custom type based on enum.IntEnum with sphinx-autoapi,

I get this warning:

/workspace/docstring of converters.ros_streamer.VerbosityLevel:1: WARNING: Unparseable C++ cross-reference: 'enum.IntEnum'
Error in cross-reference.
If shorthand ref:
  Invalid C++ declaration: Expected identifier in nested name, got keyword: enum [error at 4]
    enum.IntEnum
    ----^
If full function ref:
  Error when parsing function declaration.
  If the function has no return type:
    Error in declarator or parameters-and-qualifiers
    Invalid C++ declaration: Expected identifier in nested name, got keyword: enum [error at 4]
      enum.IntEnum
      ----^
  If the function has a return type:
    Invalid C++ declaration: Expected identifier in nested name. [error at 4]
      enum.IntEnum
      ----^

The code looks like this:

.. autoapifunction:: converters.ros_converter.ros_to_hdf


.. autoapimodule:: converters.containers
   :members:
   :undoc-members:

# ros_converter.py
from containers import VerbosityLevel

def ros_to_hdf(
    bag,
    hdf_file=None,
    verbosity=VerbosityLevel.NONE,
    topics=None,
):
    pass

# containers.py
from enum import IntEnum

class VerbosityLevel(IntEnum):
    """Defines verbosity levels."""

    NONE = 0
    LOW = 1
    HIGH = 2
    DEBUG = 3

Version info

Python: 3.8
Sphinx: 7.1.2
sphinx-autoapi: 3.3.2

config

# conf.py

# I'm configuring autoapi_dirs to include the referenced code directory...

autoapi_generate_api_docs = False
autoapi_python_use_implicit_namespaces = True
autoapi_python_class_content = "both"
autodoc_typehints = "description"

[AWhetter]

Do you have primary_domain set to cpp?
Without being able to see the docstring of converters.ros_streamer.VerbosityLevel, I'm guessing it's doing something like :obj:`enum.IntEnum`, which if primary_domain = 'cpp' means that you'll need to do :py:obj:`enum.IntEnum`.
Do you have a more complete example?