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stubtest doesn't expand **kwargs: Unpack[...] in overloads #22238
Description
Bug Report
#21024 made stubtest expand **kwargs: Unpack[TypedDict] for plain functions, but not for overloaded ones.
In django-stubs we are trying to factor the kwargs shared by every Field.__init__ overload into a TypedDict, to avoid spelling the same ones over and over.
To Reproduce
# pkg/__init__.py
def plain(*, a: int = 0, b: int = 0) -> None: ...
def overloaded(x, *, a=0, b=0): ...# pkg/__init__.pyi
from typing import Literal, TypedDict, Unpack, overload, type_check_only
@type_check_only
class KW(TypedDict, total=False):
a: int
b: int
def plain(**kwargs: Unpack[KW]) -> None: ...
@overload
def overloaded(x: Literal[True], **kwargs: Unpack[KW]) -> None: ...
@overload
def overloaded(x: bool, **kwargs: Unpack[KW]) -> None: ...PYTHONPATH=. MYPYPATH=. stubtest pkg
Expected Behavior
No errors, like for plain.
Actual Behavior
error: pkg.overloaded is inconsistent, stub does not have parameter "a"
Stub: in file pkg/__init__.pyi:9
Overload(def (x: Literal[True], **kwargs: **TypedDict(pkg.KW, {'a'?: int, 'b'?: int})), def (x: bool, **kwargs: **TypedDict(pkg.KW, {'a'?: int, 'b'?: int})))
Inferred signature: def (x: bool, **kwargs)
Runtime: in file pkg/__init__.py:2
def (x, *, a=0, b=0)
error: pkg.overloaded is inconsistent, stub does not have parameter "b"
...
error: pkg.overloaded is inconsistent, runtime does not have **kwargs parameter "kwargs"
...
Found 3 errors (checked 1 module)
Your Environment
- Mypy version used: 2.4.0
- Mypy command-line flags: none
- Mypy configuration options from mypy.ini (and other config files): none
- Python version used: 3.13
Activity
NavpreetSSidhu commented on Oct 20, 2026
I can reproduce this on master (eaeb098). The TypedDict expansion from #21024 only happens in Signature.from_funcitem. from_overloadedfuncdef builds its signature from the raw func.arguments, so overloads still see a plain **kwargs.
Moving the expansion into a small helper and calling it on each overload item's arguments fixes the example here. All stubtest tests pass, and I added overload cases to test_kwargs_unpack_typeddict. I'll open a PR shortly.
stubtest: expand Unpack[TypedDict] kwargs in overloads (#22239)