Error when trying to construct TypedDict with ** unpacking

[Dreamsorcerer]

Am I asking too much of Mypy, or am I doing something wrong with this code?

I get Incompatible types in assignment (expression has type "Dict[str, str]", variable has type "Union[_TokenParamsPassword, _TokenParamsRefresh]") [assignment] on the assignment in this function:

    async def _get_token(self, data: AuthParams) -> TokenResponse:
        request_data: TokenParams = {
            'client_id': OAUTH_CLIENT_ID,
            'client_secret': OAUTH_CLIENT_SECRET,
            **data
        }

The type definitions are:

class _AuthParamsPassword(TypedDict):
    grant_type: Literal["password"]
    email: str
    password: str
class _AuthParamsRefresh(TypedDict):
    grant_type: Literal["refresh_token"]
    refresh_token: str
AuthParams = Union[_AuthParamsPassword, _AuthParamsRefresh]

class _TokenParamsPassword(TypedDict):
    grant_type: Literal["password"]
    client_id: str
    client_secret: str
    email: str
    password: str
class _TokenParamsRefresh(TypedDict):
    grant_type: Literal["refresh_token"]
    client_id: str
    client_secret: str
    refresh_token: str
TokenParams = Union[_TokenParamsPassword, _TokenParamsRefresh]

So, I'm using the AuthParam, which is a subset of keys of TokenParam, and then building a full TokenParam dictionary from that. Is there a better way to do this?

[AlexWaygood]

Closing as a duplicate of #9408, which is a more recent issue but has a simpler repro