Mypy crashes with from .. import * import

[matzipan]

In my example at #4110 , if I change the import in backends/Bla.py to from .. import * and remove references to blamodule., like so:

I have the following directory structure:

blamodule
|-- __init__.py
|-- backends
|   |-- Bla.py
|   `-- __init__.py
`-- call_command.py

With the following contents:

• blamodule/__init__.py

from . import call_command
from . import backends

• blamodule/backends/__init__.py

from .Bla import Bla

• blamodule/backends/Bla.py

from .. import *
from typing import Iterable

class Bla:
    def __init__(self, path: str) -> None:
        self.path = path

    def method(self, options: Iterable[str]) -> str:
        return call_command.call(["BLA"])

• blamodule/call_command.py

import io

def call() -> str:

    output_buffer = io.StringIO()

    return output_buffer.getvalue()

I crash mypy with the following backtrace:

Traceback (most recent call last):
  File "/path/py3env/bin/mypy", line 11, in <module>
    sys.exit(console_entry())
  File "/path/py3env/lib/python3.5/site-packages/mypy/__main__.py", line 7, in console_entry
    main(None)
  File "/path/py3env/lib/python3.5/site-packages/mypy/main.py", line 50, in main
    res = type_check_only(sources, bin_dir, options)
  File "/path/py3env/lib/python3.5/site-packages/mypy/main.py", line 103, in type_check_only
    options=options)
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 198, in build
    graph = dispatch(sources, manager)
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1833, in dispatch
    graph = load_graph(sources, manager)
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1946, in load_graph
    caller_state=st, caller_line=st.dep_line_map.get(dep, 1))
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1466, in __init__
    self.parse_file()
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1663, in parse_file
    self.ignore_all or self.options.ignore_errors)
  File "/usr/lib/python3.5/contextlib.py", line 77, in __exit__
    self.gen.throw(type, value, traceback)
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1554, in wrap_context
    yield
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 1663, in parse_file
    self.ignore_all or self.options.ignore_errors)
  File "/path/py3env/lib/python3.5/site-packages/mypy/build.py", line 589, in parse_file
    tree = parse(source, path, self.errors, options=self.options)
  File "/path/py3env/lib/python3.5/site-packages/mypy/parse.py", line 25, in parse
    options=options)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 96, in parse
    ).visit(ast)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 169, in visit
    return super().visit(node)
  File "/path/py3env/lib/python3.5/site-packages/typed_ast/ast3.py", line 275, in visit
    return visitor(node)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 289, in visit_Module
    body = self.fix_function_overloads(self.translate_stmt_list(mod.body))
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 182, in translate_stmt_list
    stmt = self.visit(e)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 169, in visit
    return super().visit(node)
  File "/path/py3env/lib/python3.5/site-packages/typed_ast/ast3.py", line 275, in visit
    return visitor(node)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 126, in wrapper
    node = f(self, ast)
  File "/path/py3env/lib/python3.5/site-packages/mypy/fastparse.py", line 654, in visit_ImportFrom
    assert n.module is not None
AssertionError: 

[ilevkivskyi]

Yes, this is actually a regression introduced by me. Fortunately, this one is easy to fix (just replace None with '').