No error when attempting to use property object as that property's type

• Are you reporting a bug, or opening a feature request? Bug
• Please insert below the code you are checking with mypy,
  or a mock-up repro if the source is private. We would appreciate
  if you try to simplify your case to a minimal repro.

from typing import NamedTuple


class C(NamedTuple):
    a: int = 1


print(C.a * 2)

• What is the actual behavior/output?

mypy a.py produces no output.

• What is the behavior/output you expect?

An error at C.a * 2, as it will cause an error at runtime: TypeError: unsupported operand type(s) for *: 'property' and 'int'

• What are the versions of mypy and Python you are using?

python --version: 3.7.2
mypy --version: 0.660+dev.97d7760dca6d95806a97b02992ae88a082898a0e

Do you see the same issue after installing mypy from Git master? Yes

• What are the mypy flags you are using? (For example --strict-optional) None

Start by running mypy a.py with the reported example and confirm that it produces no output while Python raises the stated TypeError. Trace how mypy handles the NamedTuple property access and arithmetic expression; done means mypy reports an error at C.a * 2 for this case.