"AssertionError: Cannot find component" for local NamedTuple #7281
Description
I've got an obscure bug which I narrowed down to some cache issues when you have a local class inheriting from NamedTuple.
Stacktrace:
Traceback (most recent call last):
File "/home/karlicos/.local/bin/mypy", line 10, in <module>
sys.exit(console_entry())
File "/home/karlicos/.local/lib/python3.7/site-packages/mypy/__main__.py", line 8, in console_entry
main(None, sys.stdout, sys.stderr)
File "mypy/main.py", line 83, in main
File "mypy/build.py", line 164, in build
File "mypy/build.py", line 224, in _build
File "mypy/build.py", line 2579, in dispatch
File "mypy/build.py", line 2885, in process_graph
File "mypy/build.py", line 2963, in process_fresh_modules
File "mypy/build.py", line 1876, in fix_cross_refs
File "mypy/fixup.py", line 25, in fixup_module
File "mypy/fixup.py", line 76, in visit_symbol_table
File "mypy/fixup.py", line 265, in lookup_qualified_stnode
File "mypy/lookup.py", line 47, in lookup_fully_qualified
AssertionError: Cannot find component 'NT@3' for 'breaking.NT@3
Easiest to reproduce with the following script (it's crashing on the last mypy invocation)
#!/bin/bash -eux
cd "$(dirname "$0")"
rm -rf .mypy_cache
echo 'from typing import NamedTuple' > breaking.py
echo 'def test():' >> breaking.py
echo ' class NT(NamedTuple):' >> breaking.py
echo ' pass' >> breaking.py
echo 'import breaking' > script.py
mypy script.py
echo '' > script.py
mypy script.py
echo 'import breaking' > script.py
mypy script.py
Most similar issue to this one I found seems to be #2931, but using singleline NamedTuple definition (e.g. NT = NamedTuple('NT', [])) doesn't result in failure, so I figured this is worth separate issue.
Using @dataclass doesn't result in failure either.
I'm using mypy 0.720. (upd: still happens on 0.800)