[panic] Panic in assignment to superclass method #2597
Description
Consider:
# bug.py
from pandas.core.groupby.generic import DataFrameGroupBy
from pandas.core.groupby.groupby import GroupBy
assert GroupBy._cython_agg_general is DataFrameGroupBy._cython_agg_general
class DFGB(DataFrameGroupBy):
_cython_agg_general = GroupBy._cython_agg_generalRunning ty yields:
RUST_BACKTRACE=1 uvx --with pandas ty check bug.py
error[panic]: Panicked at crates/ruff_db/src/parsed.rs:210:13 when checking `bug.py`: `index out of bounds: the len is 25 but the index is 4000`
info: This indicates a bug in ty.
info: If you could open an issue at https://github.com/astral-sh/ty/issues/new?title=%5Bpanic%5D, we'd be very appreciative!
info: Platform: macos aarch64
info: Version: 0.0.13 (fc1478bd9 2026-01-21)
info: Args: ["ty", "check", "bug.py"]
info: Backtrace:
0: __mh_execute_header
1: __mh_execute_header
2: __mh_execute_header
3: __mh_execute_header
4: __mh_execute_header
5: __mh_execute_header
6: __mh_execute_header
7: __mh_execute_header
8: __mh_execute_header
9: __mh_execute_header
10: __mh_execute_header
11: __mh_execute_header
12: __mh_execute_header
13: __mh_execute_header
14: __mh_execute_header
15: __mh_execute_header
16: __mh_execute_header
17: __mh_execute_header
18: __mh_execute_header
19: __mh_execute_header
20: __mh_execute_header
21: __mh_execute_header
22: __mh_execute_header
23: __mh_execute_header
24: __mh_execute_header
25: __mh_execute_header
26: __mh_execute_header
27: __pthread_cond_wait
info: query stacktrace:
0: infer_scope_types_impl(Id(1000))
at crates/ty_python_semantic/src/types/infer.rs:192
1: check_file_impl(Id(c00))
at crates/ty_project/src/lib.rs:554
Found 1 diagnostic
WARN A fatal error occurred while checking some files. Not all project files were analyzed. See the diagnostics list above for details.
I failed to make this a reproducer without pandas due to time, sorry.
$ uvx ty version
ty 0.0.13 (fc1478bd9 2026-01-21)
Thanks,
Adam