dmypy crash with “Invalid type comment or annotation”

[andrewdotn]

Crash Report

On a fresh checkout of mypy HEAD, with foo.py containing

from typing import TypedDict

class C(TypedDict):
    a: {"c": int}

the command python -m mypy.dmypy run foo.py crashes the daemon.

If I run just mypy, without the daemon, I get the error

foo.py:4: error: Invalid type comment or annotation

but dmypy doesn’t seem to get far enough to report that.

Traceback

Daemon started
Daemon crashed!
Traceback (most recent call last):
File "~/git/mypy/mypy/dmypy_server.py", line 221, in serve
    resp = self.run_command(command, data)
File "~/git/mypy/mypy/dmypy_server.py", line 264, in run_command
    return method(self, **data)
File "~/git/mypy/mypy/dmypy_server.py", line 323, in cmd_run
    return self.check(sources, is_tty, terminal_width)
File "~/git/mypy/mypy/dmypy_server.py", line 380, in check
    res = self.initialize_fine_grained(sources, is_tty, terminal_width)
File "~/git/mypy/mypy/dmypy_server.py", line 410, in initialize_fine_grained
    result = mypy.build.build(sources=sources,
File "~/git/mypy/mypy/build.py", line 180, in build
    result = _build(
File "~/git/mypy/mypy/build.py", line 254, in _build
    graph = dispatch(sources, manager, stdout)
File "~/git/mypy/mypy/build.py", line 2656, in dispatch
    process_graph(graph, manager)
File "~/git/mypy/mypy/build.py", line 2982, in process_graph
    process_stale_scc(graph, scc, manager)
File "~/git/mypy/mypy/build.py", line 3083, in process_stale_scc
    graph[id].finish_passes()
File "~/git/mypy/mypy/build.py", line 2177, in finish_passes
    self.update_fine_grained_deps(self.manager.fg_deps)
File "~/git/mypy/mypy/build.py", line 2225, in update_fine_grained_deps
    merge_dependencies(self.compute_fine_grained_deps(), deps)
File "~/git/mypy/mypy/build.py", line 2216, in compute_fine_grained_deps
    return get_dependencies(target=self.tree,
File "~/git/mypy/mypy/server/deps.py", line 114, in get_dependencies
    target.accept(visitor)
File "~/git/mypy/mypy/nodes.py", line 305, in accept
    return visitor.visit_mypy_file(self)
File "~/git/mypy/mypy/server/deps.py", line 176, in visit_mypy_file
    super().visit_mypy_file(o)
File "~/git/mypy/mypy/traverser.py", line 35, in visit_mypy_file
    d.accept(self)
File "~/git/mypy/mypy/nodes.py", line 950, in accept
    return visitor.visit_class_def(self)
File "~/git/mypy/mypy/server/deps.py", line 239, in visit_class_def
    super().visit_class_def(o)
File "~/git/mypy/mypy/traverser.py", line 71, in visit_class_def
    o.defs.accept(self)
File "~/git/mypy/mypy/nodes.py", line 1015, in accept
    return visitor.visit_block(self)
File "~/git/mypy/mypy/server/deps.py", line 351, in visit_block
    super().visit_block(o)
File "~/git/mypy/mypy/traverser.py", line 39, in visit_block
    s.accept(self)
File "~/git/mypy/mypy/nodes.py", line 1073, in accept
    return visitor.visit_assignment_stmt(self)
File "~/git/mypy/mypy/server/deps.py", line 411, in visit_assignment_stmt
    self.add_type_dependencies(o.type)
File "~/git/mypy/mypy/server/deps.py", line 808, in add_type_dependencies
    for trigger in self.get_type_triggers(typ):
File "~/git/mypy/mypy/server/deps.py", line 861, in get_type_triggers
    return get_type_triggers(typ, self.use_logical_deps())
File "~/git/mypy/mypy/server/deps.py", line 866, in get_type_triggers
    return typ.accept(TypeTriggersVisitor(use_logical_deps))
File "~/git/mypy/mypy/types.py", line 1620, in accept
    assert isinstance(visitor, SyntheticTypeVisitor)
AssertionError

To Reproduce

See above

Your Environment

python 3.9.1 on macOS 11.1