super(type, cls).__new__ saying not an instance when it is

When upgrading to the latest mypy I started getting a weird new error. Here's a simplified example:

class X:
    def __new__(cls) -> "X":
        return super(type, cls).__new__(cls)    # error: Argument 2 for "super" not an instance of argument 1

However:

>>> isinstance(X, type) 
True

My settings: mypy 0.730

[mypy]
python_version=3.6
incremental=True
ignore_missing_imports=True
follow_imports=normal
warn_redundant_casts=True
warn_unused_ignores=True
strict_optional=True
no_implicit_optional=True
disallow_untyped_defs=True
disallow_any_generics=True

(Note: I'm using super to skip an inherited __new__ when I create the object.)

Start by running the minimal X.new example with mypy 0.730 and inspect how the checker handles super(type, cls) and the new call. No source files or tests are named in the report; done means the valid example no longer produces the instance-type error, with coverage for this regression.