Crash with forward reference in NamedTuple #3315
Description
Found this testing my production codebase against mypy master:
(venv) jelle@devjelle:~/mypy$ cat testnt.py
from typing import NamedTuple
class A(NamedTuple):
b: 'B'
x: int
class B:
pass
(venv) jelle@devjelle:~/mypy$ python -m mypy --show-traceback testnt.py
testnt.py:3: error: INTERNAL ERROR -- please report a bug at https://github.com/python/mypy/issues version: 0.510-dev-09e7b124b82dae1207d9eac6805b64a98290015c
Traceback (most recent call last):
File "/home/jelle/ans/venv64/lib/python3.6/runpy.py", line 193, in _run_module_as_main
"__main__", mod_spec)
File "/home/jelle/ans/venv64/lib/python3.6/runpy.py", line 85, in _run_code
exec(code, run_globals)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/__main__.py", line 5, in <module>
main(None)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/main.py", line 46, in main
res = type_check_only(sources, bin_dir, options)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/main.py", line 93, in type_check_only
options=options)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/build.py", line 188, in build
graph = dispatch(sources, manager)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/build.py", line 1595, in dispatch
process_graph(graph, manager)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/build.py", line 1838, in process_graph
process_stale_scc(graph, scc, manager)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/build.py", line 1931, in process_stale_scc
graph[id].semantic_analysis()
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/build.py", line 1495, in semantic_analysis
self.manager.semantic_analyzer.visit_file(self.tree, self.xpath, self.options)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 257, in visit_file
self.accept(d)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 3279, in accept
node.accept(self)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/nodes.py", line 749, in accept
return visitor.visit_class_def(self)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 617, in visit_class_def
with self.analyze_class_body(defn) as should_continue:
File "/home/jelle/ans/venv64/lib/python3.6/contextlib.py", line 82, in __enter__
return next(self.gen)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 629, in analyze_class_body
if self.analyze_namedtuple_classdef(defn):
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 819, in analyze_namedtuple_classdef
defn.name, items, types, default_items)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/semanal.py", line 2053, in build_namedtuple_typeinfo
fallback = self.named_type('__builtins__.tuple', [join.join_type_list(types)])
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/join.py", line 388, in join_type_list
joined = join_types(joined, t)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/join.py", line 88, in join_types
return t.accept(TypeJoinVisitor(s))
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/types.py", line 411, in accept
return visitor.visit_instance(self)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/join.py", line 141, in visit_instance
return join_instances(t, self.s)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/join.py", line 295, in join_instances
return join_instances_via_supertype(s, t)
File "/home/jelle/mypy/venv/lib/python3.6/site-packages/mypy/join.py", line 314, in join_instances_via_supertype
assert best is not None
AssertionError:
testnt.py:3: note: use --pdb to drop into pdb
Haven't tried yet to minimize this further. Hopefully we can get this fixed before the release.
Edit: this also repros with TypedDict:
from mypy_extensions import TypedDict
X = TypedDict('X', {'b': 'B', 'c': int})
class B: pass