Erroneous 'Too many arguments' error #4997

It appears as though mypy treats argument unpacking as containing at least one element. Here's an example:

from typing import List

class Foo:
    pass

args: List[str] = []
packet = Foo(*args)

tbug.py:7: error: Too many arguments for "Foo"

I guess Mypy is assuming that you would never unpack zero arguments.

In my particular case I have a registry of 'packet classes' and a dynamic number of arguments parsed from the network. Some of those packet classes legitimately have 0 parameters, and Mypy gives me an error about each of them.

Running mypy 0.600 with no other flags.