$ pip3 install --user --upgrade git+https://github.com/python/mypy.git
[...]
Successfully installed mypy-0.820+dev.28718facbeea5b3c33ec96bc335bb018d3b0a395



$ cat mypy_crash.py
*e



$ mypy --show-traceback mypy_crash.py
mypy_crash.py:1: error: Can use starred expression only as assignment target
mypy_crash.py: error: INTERNAL ERROR -- Please try using mypy master on Github:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 0.820+dev.28718facbeea5b3c33ec96bc335bb018d3b0a395
Traceback (most recent call last):
  File "/home/dev/.local/bin/mypy", line 8, in <module>
    sys.exit(console_entry())
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/__main__.py", line 11, in console_entry
    main(None, sys.stdout, sys.stderr)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/main.py", line 98, in main
    res = build.build(sources, options, None, flush_errors, fscache, stdout, stderr)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 180, in build
    sources, options, alt_lib_path, flush_errors, fscache, stdout, stderr, extra_plugins
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 253, in _build
    graph = dispatch(sources, manager, stdout)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 2689, in dispatch
    process_graph(graph, manager)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 3013, in process_graph
    process_stale_scc(graph, scc, manager)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 3114, in process_stale_scc
    graph[id].finish_passes()
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 2209, in finish_passes
    free_tree(self.tree)
  File "/usr/lib/python3.7/contextlib.py", line 130, in __exit__
    self.gen.throw(type, value, traceback)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 1954, in wrap_context
    yield
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 2196, in finish_passes
    self._patch_indirect_dependencies(self.type_checker().module_refs, self.type_map())
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/build.py", line 2223, in _patch_indirect_dependencies
    encountered = self.manager.indirection_detector.find_modules(types) | module_refs
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/indirection.py", line 27, in find_modules
    return self._visit(typs)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/indirection.py", line 41, in _visit
    modules = typ.accept(self)
  File "/home/dev/.local/lib/python3.7/site-packages/mypy/types.py", line 1737, in accept
    assert isinstance(visitor, SyntheticTypeVisitor)
AssertionError: 
mypy_crash.py: : note: use --pdb to drop into pdb