Internal error when identifier in except clause shadows imported module name

[ethframe]

Crash Report

Mypy crashes while analysing a try statement in which one of the except clauses uses the same identifier as one of the imported modules.

Traceback

bug.py:3: error: INTERNAL ERROR -- Please try using mypy master on Github:
https://mypy.rtfd.io/en/latest/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 0.790
Traceback (most recent call last):
  File "C:\Users\User\AppData\Local\Programs\Python\Python36\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\Users\User\AppData\Local\Programs\Python\Python36\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "mypy\checker.py", line 401, in accept
  File "mypy\nodes.py", line 1235, in accept
  File "mypy\checker.py", line 3350, in visit_try_stmt
  File "mypy\checker.py", line 3403, in visit_try_without_finally
  File "mypy\checker.py", line 2053, in check_assignment
  File "mypy\checker.py", line 2799, in check_lvalue
TypeError: mypy.nodes.Var object expected; got mypy.nodes.MypyFile
bug.py:3: : note: use --pdb to drop into pdb

To Reproduce

bug.py contents:

import re

try:
    pass
except Exception as re:
    pass

Command: mypy bug.py

Your Environment

• Mypy version used: 0.790
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.6.8
• Operating system and version: Windows 10 2004

[andrewgodwin]

It's worth noting that a very similar problem occurs when the identifier in the except clause is declared global, but that identifier is not declared in the outside scope:

# Note that e is not defined out here
def main()
    global e
    try:
        ...
    except Exception as e:
        pass

This results in TypeError: mypy.nodes.Var object expected; got None