Embedded TypedDict produces AST error on Python 3.10

[Andrew-Chen-Wang]

Bug in TypedDict AST parsing running on Python 3.10. Runs fine during running of Python application/web server with no output. Black and isort formatting doesn't have a problem either. Example code:

CycleT = TypedDict(
    "CycleT",
    {
        "query": list[
            TypedDict(
                "query",
                {
                    "branches": list[
                        TypedDict(
                            "branches",
                            {
                                "branches": list[
                                    TypedDict(
                                        "branches",
                                        {
                                            "branches": list[
                                                TypedDict(
                                                    "branches",
                                                    {"count": int},
                                                )
                                            ]
                                        },
                                    )
                                ]
                            },
                        )
                    ]
                },
            )
        ],
    },
)

Pre-commit file

  - repo: https://github.com/asottile/pyupgrade
    rev: v3.3.1
    hooks:
      - id: pyupgrade
        args: ['--py310-plus', '--keep-mock']

Stacktrace

pyupgrade................................................................Failed
- hook id: pyupgrade
- exit code: 1

Traceback (most recent call last):
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/bin/pyupgrade", line 8, in <module>
    sys.exit(main())
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_main.py", line 381, in main
    ret |= _fix_file(filename, args)
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_main.py", line 318, in _fix_file
    contents_text = _fix_plugins(
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_main.py", line 80, in _fix_plugins
    callback(i, tokens)
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_plugins/typing_classes.py", line 143, in _fix_dict_typed_dict
    end, attrs = _typed_class_replacement(tokens, i, call, types)
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_plugins/typing_classes.py", line 84, in _typed_class_replacement
    member = f'{indent}{k}: {_unparse(v)}'
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_plugins/typing_classes.py", line 39, in _unparse
    slice_s = _unparse(node_slice)
  File "/Users/andrewcwang/.cache/pre-commit/repoof0hoxn7/py_env-python3.10/lib/python3.10/site-packages/pyupgrade/_plugins/typing_classes.py", line 52, in _unparse
    raise NotImplementedError(ast.dump(node))
NotImplementedError: Call(func=Name(id='TypedDict', ctx=Load()), args=[Constant(value='query'), Dict(keys=[Constant(value='branches')], values=[Subscript(value=Name(id='list', ctx=Load()), slice=Call(func=Name(id='TypedDict', ctx=Load()), args=[Constant(value='branches'), Dict(keys=[Constant(value='branches')], values=[Subscript(value=Name(id='list', ctx=Load()), slice=Call(func=Name(id='TypedDict', ctx=Load()), args=[Constant(value='branches'), Dict(keys=[Constant(value='branches')], values=[Subscript(value=Name(id='list', ctx=Load()), slice=Call(func=Name(id='TypedDict', ctx=Load()), args=[Constant(value='branches'), Dict(keys=[Constant(value='count')], values=[Name(id='int', ctx=Load())])], keywords=[]), ctx=Load())])], keywords=[]), ctx=Load())])], keywords=[]), ctx=Load())])], keywords=[])