[ty] Only prefer declared types in non-covariant positions by ibraheemdev · Pull Request #22068 · astral-sh/ruff

ibraheemdev · 2025-12-19T04:24:35Z

Summary

The following snippet currently errors because we widen the inferred type, even though X is covariant over T. If T was contravariant or invariant, this would be fine, as it would lead to an assignability error anyways.

class X[T]:
    def __init__(self: X[None]): ...

    def pop(self) -> T:
        raise NotImplementedError

# error: Argument to bound method `__init__` is incorrect: Expected `X[None]`, found `X[int | None]`
x: X[int | None] = X()

There are some cases where it is still helpful to prefer covariant declared types, but this error seems hard to fix otherwise, and makes our heuristics more consistent overall.

astral-sh-bot · 2025-12-19T04:26:24Z

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

astral-sh-bot · 2025-12-19T04:27:37Z

`mypy_primer` results

Changes were detected when running on open source projects

anyio (https://github.com/agronholm/anyio)
- src/anyio/_backends/_asyncio.py:2564:50: error[invalid-assignment] Object of type `Future[T_Retval@run_async_from_thread] | Future[_T@run_coroutine_threadsafe]` is not assignable to `Future[T_Retval@run_async_from_thread]`
+ src/anyio/_backends/_asyncio.py:2564:50: error[invalid-assignment] Object of type `Future[_T@run_coroutine_threadsafe] | Future[T_Retval@run_async_from_thread]` is not assignable to `Future[T_Retval@run_async_from_thread]`

beartype (https://github.com/beartype/beartype)
+ beartype/claw/_ast/_kind/clawastimport.py:622:68: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
+ beartype/claw/_ast/_kind/clawastimport.py:631:72: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- Found 491 diagnostics
+ Found 493 diagnostics

scrapy (https://github.com/scrapy/scrapy)
- tests/test_pipeline_files.py:370:28: error[invalid-assignment] Object of type `dataclasses.Field[list[str] | <class 'list'>]` is not assignable to `list[str]`
+ tests/test_pipeline_files.py:370:28: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[str]]` is not assignable to `list[str]`
- tests/test_pipeline_files.py:371:35: error[invalid-assignment] Object of type `dataclasses.Field[list[dict[str, str]] | <class 'list'>]` is not assignable to `list[dict[str, str]]`
+ tests/test_pipeline_files.py:371:35: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[dict[str, str]]]` is not assignable to `list[dict[str, str]]`
- tests/test_pipeline_files.py:373:35: error[invalid-assignment] Object of type `dataclasses.Field[list[str] | <class 'list'>]` is not assignable to `list[str]`
+ tests/test_pipeline_files.py:373:35: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[str]]` is not assignable to `list[str]`
- tests/test_pipeline_files.py:374:42: error[invalid-assignment] Object of type `dataclasses.Field[list[dict[str, str]] | <class 'list'>]` is not assignable to `list[dict[str, str]]`
+ tests/test_pipeline_files.py:374:42: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[dict[str, str]]]` is not assignable to `list[dict[str, str]]`
- tests/test_pipeline_images.py:332:29: error[invalid-assignment] Object of type `dataclasses.Field[list[str] | <class 'list'>]` is not assignable to `list[str]`
+ tests/test_pipeline_images.py:332:29: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[str]]` is not assignable to `list[str]`
- tests/test_pipeline_images.py:333:36: error[invalid-assignment] Object of type `dataclasses.Field[list[dict[str, str]] | <class 'list'>]` is not assignable to `list[dict[str, str]]`
+ tests/test_pipeline_images.py:333:36: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[dict[str, str]]]` is not assignable to `list[dict[str, str]]`
- tests/test_pipeline_images.py:335:36: error[invalid-assignment] Object of type `dataclasses.Field[list[str] | <class 'list'>]` is not assignable to `list[str]`
+ tests/test_pipeline_images.py:335:36: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[str]]` is not assignable to `list[str]`
- tests/test_pipeline_images.py:336:43: error[invalid-assignment] Object of type `dataclasses.Field[list[dict[str, str]] | <class 'list'>]` is not assignable to `list[dict[str, str]]`
+ tests/test_pipeline_images.py:336:43: error[invalid-assignment] Object of type `dataclasses.Field[<class 'list'> | list[dict[str, str]]]` is not assignable to `list[dict[str, str]]`

mypy (https://github.com/python/mypy)
- mypyc/irbuild/util.py:35:44: error[invalid-assignment] Object of type `frozenset[str | Unknown]` is not assignable to `frozenset[Literal["native_class", "allow_interpreted_subclasses", "serializable", "free_list_len"]]`
+ mypyc/irbuild/util.py:35:44: error[invalid-assignment] Object of type `frozenset[Unknown | str]` is not assignable to `frozenset[Literal["native_class", "allow_interpreted_subclasses", "serializable", "free_list_len"]]`

psycopg (https://github.com/psycopg/psycopg)
- tests/typing_example.py:100:13: error[invalid-assignment] Object of type `Connection[int] | Connection[tuple[Any, ...]]` is not assignable to `Connection[int]`
+ tests/typing_example.py:100:13: error[invalid-assignment] Object of type `Connection[tuple[Any, ...]] | Connection[int]` is not assignable to `Connection[int]`
- tests/typing_example.py:110:13: error[invalid-assignment] Object of type `Connection[Person] | Connection[tuple[Any, ...]]` is not assignable to `Connection[Person]`
+ tests/typing_example.py:110:13: error[invalid-assignment] Object of type `Connection[tuple[Any, ...]] | Connection[Person]` is not assignable to `Connection[Person]`

freqtrade (https://github.com/freqtrade/freqtrade)
- freqtrade/optimize/analysis/lookahead.py:48:13: error[invalid-argument-type] Argument to bound method `backtest` is incorrect: Expected `dict[Unknown, Unknown]`, found `dict[Unknown, Unknown] | DataFrame`
+ freqtrade/optimize/analysis/lookahead.py:48:13: error[invalid-argument-type] Argument to bound method `backtest` is incorrect: Expected `dict[Unknown, Unknown]`, found `DataFrame | dict[Unknown, Unknown]`

Tanjun (https://github.com/FasterSpeeding/Tanjun)
- tanjun/context/menu.py:57:96: error[invalid-assignment] Object of type `frozenset[CommandType | Unknown]` is not assignable to `frozenset[Literal[CommandType.USER, CommandType.MESSAGE]]`
+ tanjun/context/menu.py:57:96: error[invalid-assignment] Object of type `frozenset[Unknown | CommandType]` is not assignable to `frozenset[Literal[CommandType.USER, CommandType.MESSAGE]]`

Expression (https://github.com/cognitedata/Expression)
- expression/collections/array.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `TypedArray[_TSource@TypedArray]`, found `TypedArray[_TSource@TypedArray] | Unknown | _TState@unfold`
+ expression/collections/array.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `TypedArray[_TSource@TypedArray]`, found `Unknown | _TState@unfold | TypedArray[_TSource@TypedArray]`
- expression/collections/block.py:486:16: error[invalid-return-type] Return type does not match returned value: expected `Block[_TSource@Block]`, found `Block[_TSource@Block] | Unknown | _TState@unfold`
+ expression/collections/block.py:486:16: error[invalid-return-type] Return type does not match returned value: expected `Block[_TSource@Block]`, found `Unknown | _TState@unfold | Block[_TSource@Block]`
- expression/collections/block.py:595:12: error[invalid-return-type] Return type does not match returned value: expected `Block[_TSource@concat]`, found `Block[_TSource@concat] | Unknown | Iterable[Block[_TSource@concat]]`
+ expression/collections/block.py:595:12: error[invalid-return-type] Return type does not match returned value: expected `Block[_TSource@concat]`, found `Unknown | Iterable[Block[_TSource@concat]] | Block[_TSource@concat]`
- expression/core/result.py:121:24: error[invalid-return-type] Return type does not match returned value: expected `Result[_TResult@map2, _TErrorOut@Result]`, found `Result[_TResult@map2 | Unknown | _TOther@map2, _TErrorOut@Result]`
+ expression/core/result.py:121:24: error[invalid-return-type] Return type does not match returned value: expected `Result[_TResult@map2, _TErrorOut@Result]`, found `Result[Unknown | _TOther@map2 | _TResult@map2, _TErrorOut@Result]`
- expression/effect/result.py:33:16: error[invalid-return-type] Return type does not match returned value: expected `Result[_TResult@bind, _TError@ResultBuilder]`, found `Result[_TResult@bind, _TError@ResultBuilder] | Unknown | Result[_TSource@ResultBuilder, _TError@ResultBuilder]`
+ expression/effect/result.py:33:16: error[invalid-return-type] Return type does not match returned value: expected `Result[_TResult@bind, _TError@ResultBuilder]`, found `Unknown | Result[_TSource@ResultBuilder, _TError@ResultBuilder] | Result[_TResult@bind, _TError@ResultBuilder]`
- tests/test_array.py:47:27: error[invalid-assignment] Object of type `TypedArray[str] | Unknown | TypedArray[Unknown | int]` is not assignable to `TypedArray[str]`
+ tests/test_array.py:47:27: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | int] | TypedArray[str]` is not assignable to `TypedArray[str]`
- tests/test_array.py:58:35: error[invalid-assignment] Object of type `TypedArray[uint8] | Unknown | TypedArray[Unknown | str]` is not assignable to `TypedArray[uint8]`
+ tests/test_array.py:58:35: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | str] | TypedArray[uint8]` is not assignable to `TypedArray[uint8]`
- tests/test_array.py:69:36: error[invalid-assignment] Object of type `TypedArray[uint16] | Unknown | TypedArray[Unknown | str]` is not assignable to `TypedArray[uint16]`
+ tests/test_array.py:69:36: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | str] | TypedArray[uint16]` is not assignable to `TypedArray[uint16]`
- tests/test_array.py:80:36: error[invalid-assignment] Object of type `TypedArray[uint32] | Unknown | TypedArray[Unknown | str]` is not assignable to `TypedArray[uint32]`
+ tests/test_array.py:80:36: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | str] | TypedArray[uint32]` is not assignable to `TypedArray[uint32]`
- tests/test_array.py:91:37: error[invalid-assignment] Object of type `TypedArray[float32] | Unknown | TypedArray[Unknown | str]` is not assignable to `TypedArray[float32]`
+ tests/test_array.py:91:37: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | str] | TypedArray[float32]` is not assignable to `TypedArray[float32]`
- tests/test_array.py:99:35: error[invalid-assignment] Object of type `TypedArray[int16] | Unknown | TypedArray[Unknown | int]` is not assignable to `TypedArray[int16]`
+ tests/test_array.py:99:35: error[invalid-assignment] Object of type `Unknown | TypedArray[Unknown | int] | TypedArray[int16]` is not assignable to `TypedArray[int16]`
+ tests/test_result.py:491:21: error[invalid-argument-type] Argument to bound method `or_else` is incorrect: Expected `Result[Literal[42], Any]`, found `Result[Literal[0, 42], Any]`
+ tests/test_result.py:509:21: error[invalid-argument-type] Argument to bound method `or_else` is incorrect: Expected `Result[Any, Literal["original error"]]`, found `Result[Any, Literal["new error", "original error"]]`
- Found 226 diagnostics
+ Found 228 diagnostics

discord.py (https://github.com/Rapptz/discord.py)
+ discord/interactions.py:386:16: error[invalid-return-type] Return type does not match returned value: expected `InteractionResponse[ClientT@Interaction]`, found `InteractionResponse[Client]`
- Found 557 diagnostics
+ Found 558 diagnostics

mongo-python-driver (https://github.com/mongodb/mongo-python-driver)
- pymongo/synchronous/database.py:938:20: error[no-matching-overload] No overload of bound method `_command` matches arguments
- Found 446 diagnostics
+ Found 445 diagnostics

pandera (https://github.com/pandera-dev/pandera)
- tests/mypy/pandas_modules/pandas_dataframe.py:35:12: error[invalid-return-type] Return type does not match returned value: expected `DataFrame[SchemaOut]`, found `DataFrame[SchemaOut] | DataFrame[AnotherSchema]`
+ tests/mypy/pandas_modules/pandas_dataframe.py:35:12: error[invalid-return-type] Return type does not match returned value: expected `DataFrame[SchemaOut]`, found `DataFrame[AnotherSchema] | DataFrame[SchemaOut]`
- tests/mypy/pandas_modules/pandas_dataframe.py:41:12: error[invalid-return-type] Return type does not match returned value: expected `DataFrame[SchemaOut]`, found `DataFrame[SchemaOut] | DataFrame[Schema]`
+ tests/mypy/pandas_modules/pandas_dataframe.py:41:12: error[invalid-return-type] Return type does not match returned value: expected `DataFrame[SchemaOut]`, found `DataFrame[Schema] | DataFrame[SchemaOut]`

cloud-init (https://github.com/canonical/cloud-init)
+ tests/unittests/sources/test_lxd.py:40:5: error[non-subscriptable] Cannot subscript object of type `int` with no `__getitem__` method
+ tests/unittests/test_net.py:5345:41: warning[possibly-missing-attribute] Attribute `keys` may be missing on object of type `Unknown | list[Unknown | str] | dict[Unknown | str, Unknown | str | None] | dict[Unknown, Unknown]`
+ tests/unittests/test_net.py:5502:41: warning[possibly-missing-attribute] Attribute `keys` may be missing on object of type `Unknown | list[Unknown | str] | dict[Unknown | str, Unknown | str | None] | dict[Unknown | str, Unknown | str]`
- Found 1181 diagnostics
+ Found 1184 diagnostics

openlibrary (https://github.com/internetarchive/openlibrary)
- openlibrary/plugins/upstream/mybooks.py:477:13: error[invalid-argument-type] Argument to function `__new__` is incorrect: Expected `SupportsKeysAndGetItem[Literal["want-to-read", "already-read", "currently-reading"], Literal["Want to Read", "Already Read", "Currently Reading"]]`, found `dict[Unknown | str, Unknown | str]`
- Found 1153 diagnostics
+ Found 1152 diagnostics

xarray (https://github.com/pydata/xarray)
- xarray/core/dataset.py:912:47: error[invalid-argument-type] Argument to bound method `_construct_direct` is incorrect: Expected `dict[Unknown, Unknown] | None`, found `dict[Hashable, Any] | None | Default`
- xarray/core/dataset.py:912:63: error[invalid-argument-type] Argument to bound method `_construct_direct` is incorrect: Expected `dict[Unknown, Unknown] | None`, found `dict[Unknown, Unknown] | None | Default`
+ xarray/core/dataset.py:2565:52: error[invalid-argument-type] Argument to function `either_dict_or_kwargs` is incorrect: Expected `Mapping[Any, Resampler | str | int | tuple[int, ...] | None] | None`, found `(str & Top[Mapping[Unknown, object]]) | (int & Top[Mapping[Unknown, object]]) | (tuple[int, ...] & Top[Mapping[Unknown, object]]) | ... omitted 3 union elements`
- Found 1770 diagnostics
+ Found 1769 diagnostics

prefect (https://github.com/PrefectHQ/prefect)
- src/integrations/prefect-databricks/prefect_databricks/models/jobs.py:3849:38: error[invalid-assignment] Object of type `dataclasses.Field[dict[str, Any] | None | Literal["{}"]]` is not assignable to `dict[str, Any] | None`
+ src/integrations/prefect-databricks/prefect_databricks/models/jobs.py:3849:38: error[invalid-assignment] Object of type `dataclasses.Field[Literal["{}"] | dict[str, Any] | None]` is not assignable to `dict[str, Any] | None`
- src/integrations/prefect-dbt/prefect_dbt/core/settings.py:94:28: error[invalid-assignment] Object of type `dict[str, Any] | T@resolve_block_document_references` is not assignable to `dict[str, Any]`
+ src/integrations/prefect-dbt/prefect_dbt/core/settings.py:94:28: error[invalid-assignment] Object of type `T@resolve_block_document_references | dict[str, Any] | str | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/integrations/prefect-dbt/prefect_dbt/core/settings.py:99:28: error[invalid-assignment] Object of type `dict[str, Any] | T@resolve_variables` is not assignable to `dict[str, Any]`
+ src/integrations/prefect-dbt/prefect_dbt/core/settings.py:99:28: error[invalid-assignment] Object of type `T@resolve_variables | str | int | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/prefect/_states.py:219:29: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `list[State[Any]]`, found `Collection[State[Any] | R@return_value_to_state_sync]`
+ src/prefect/_states.py:219:29: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `list[State[Any]]`, found `Collection[R@return_value_to_state_sync | State[Any]]`
- src/prefect/cli/deploy/_core.py:86:21: error[invalid-assignment] Object of type `T@resolve_block_document_references | dict[str, Any]` is not assignable to `dict[str, Any]`
+ src/prefect/cli/deploy/_core.py:86:21: error[invalid-assignment] Object of type `T@resolve_block_document_references | dict[str, Any] | str | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/prefect/cli/deploy/_core.py:87:21: error[invalid-assignment] Object of type `T@resolve_variables` is not assignable to `dict[str, Any]`
+ src/prefect/cli/deploy/_core.py:87:21: error[invalid-assignment] Object of type `T@resolve_variables | str | int | ... omitted 4 union elements` is not assignable to `dict[str, Any]`
- src/prefect/deployments/steps/core.py:137:38: error[invalid-argument-type] Argument is incorrect: Expected `T@resolve_variables`, found `T@resolve_block_document_references | dict[str, Any]`
+ src/prefect/deployments/steps/core.py:137:38: error[invalid-argument-type] Argument is incorrect: Expected `T@resolve_variables`, found `T@resolve_block_document_references | dict[str, Any] | str | ... omitted 4 union elements`
- src/prefect/states.py:369:29: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `list[State[Any]]`, found `Collection[State[Any] | R@return_value_to_state]`
+ src/prefect/states.py:369:29: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `list[State[Any]]`, found `Collection[R@return_value_to_state | State[Any]]`
- src/prefect/tasks.py:1200:16: error[no-matching-overload] No overload of function `run_task` matches arguments
+ src/prefect/tasks.py:1200:16: error[invalid-return-type] Return type does not match returned value: expected `T@__call__ | State[T@__call__] | None`, found `State[T@__call__] | T@__call__ | State[Never]`
- src/prefect/utilities/templating.py:320:13: error[invalid-assignment] Invalid subscript assignment with key of type `object` and value of type `T@resolve_block_document_references | dict[str, Any]` on object of type `dict[str, Any]`
+ src/prefect/utilities/templating.py:320:13: error[invalid-assignment] Invalid subscript assignment with key of type `object` and value of type `T@resolve_block_document_references | dict[str, Any] | str | ... omitted 4 union elements` on object of type `dict[str, Any]`
- src/prefect/utilities/templating.py:323:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_block_document_references | dict[str, Any]`, found `list[T@resolve_block_document_references | dict[str, Any] | Unknown]`
+ src/prefect/utilities/templating.py:323:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_block_document_references | dict[str, Any]`, found `list[T@resolve_block_document_references | dict[str, Any] | str | ... omitted 5 union elements]`
- src/prefect/utilities/templating.py:437:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `dict[object, T@resolve_variables | Unknown]`
+ src/prefect/utilities/templating.py:437:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `dict[object, T@resolve_variables | str | int | ... omitted 5 union elements]`
- src/prefect/utilities/templating.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `list[T@resolve_variables | Unknown]`
+ src/prefect/utilities/templating.py:442:16: error[invalid-return-type] Return type does not match returned value: expected `T@resolve_variables`, found `list[T@resolve_variables | str | int | ... omitted 5 union elements]`
- src/prefect/variables.py:90:16: error[invalid-return-type] Return type does not match returned value: expected `Variable[str | int | float | ... omitted 3 union elements]`, found `Variable[str | int | float | ... omitted 3 union elements] | Self@aset`
+ src/prefect/variables.py:90:16: error[invalid-return-type] Return type does not match returned value: expected `Variable[str | int | float | ... omitted 3 union elements]`, found `Self@aset | Variable[str | int | float | ... omitted 3 union elements]`
- src/prefect/variables.py:139:20: error[invalid-return-type] Return type does not match returned value: expected `Variable[str | int | float | ... omitted 3 union elements]`, found `Variable[str | int | float | ... omitted 3 union elements] | Self@set`
+ src/prefect/variables.py:139:20: error[invalid-return-type] Return type does not match returned value: expected `Variable[str | int | float | ... omitted 3 union elements]`, found `Self@set | Variable[str | int | float | ... omitted 3 union elements]`
- src/prefect/workers/base.py:228:13: error[invalid-argument-type] Argument is incorrect: Expected `T@resolve_variables`, found `T@resolve_block_document_references | dict[str, Any]`
+ src/prefect/workers/base.py:228:13: error[invalid-argument-type] Argument is incorrect: Expected `T@resolve_variables`, found `T@resolve_block_document_references | dict[str, Any] | str | ... omitted 4 union elements`
- src/prefect/workers/base.py:230:20: error[invalid-argument-type] Argument expression after ** must be a mapping type: Found `T@resolve_variables`
+ src/prefect/workers/base.py:230:20: error[invalid-argument-type] Argument expression after ** must be a mapping type: Found `T@resolve_variables | str | int | ... omitted 4 union elements`

setuptools (https://github.com/pypa/setuptools)
- setuptools/_vendor/typing_extensions.py:3546:30: error[invalid-argument-type] Argument to function `__new__` is incorrect: Expected `Iterable[str]`, found `object`
+ setuptools/_vendor/typing_extensions.py:3546:30: error[invalid-argument-type] Argument to function `__new__` is incorrect: Expected `Iterable[Unknown]`, found `object`

scikit-build-core (https://github.com/scikit-build/scikit-build-core)
+ src/scikit_build_core/build/wheel.py:98:20: error[no-matching-overload] No overload of bound method `__init__` matches arguments
- Found 43 diagnostics
+ Found 44 diagnostics

dd-trace-py (https://github.com/DataDog/dd-trace-py)
- tests/testing/mocks.py:668:25: error[invalid-argument-type] Argument to function `next` is incorrect: Expected `SupportsNext[dict[str, Any]]`, found `Iterable[dict[str, Any]]`
+ tests/testing/mocks.py:668:25: error[invalid-argument-type] Argument to function `next` is incorrect: Expected `SupportsNext[Unknown]`, found `Iterable[dict[str, Any]]`

pandas (https://github.com/pandas-dev/pandas)
- pandas/core/algorithms.py:546:33: error[invalid-argument-type] Argument to bound method `isin` is incorrect: Expected `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]]`, found `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
+ pandas/core/algorithms.py:546:33: error[invalid-argument-type] Argument to bound method `isin` is incorrect: Expected `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]]`, found `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | (Index & ~MultiIndex) | (Series & ~MultiIndex) | (SequenceNotStr[Unknown] & ndarray[tuple[object, ...], dtype[object]] & ~MultiIndex)`
- pandas/core/algorithms.py:551:30: warning[possibly-missing-attribute] Attribute `dtype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
- pandas/core/algorithms.py:555:30: warning[possibly-missing-attribute] Attribute `dtype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
- pandas/core/algorithms.py:556:34: warning[possibly-missing-attribute] Attribute `astype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
- pandas/core/algorithms.py:558:21: warning[possibly-missing-attribute] Attribute `dtype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
- pandas/core/algorithms.py:586:38: warning[possibly-missing-attribute] Attribute `dtype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
- pandas/core/algorithms.py:587:18: warning[possibly-missing-attribute] Attribute `astype` may be missing on object of type `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 3 union elements`
+ pandas/core/algorithms.py:556:34: error[no-matching-overload] No overload of bound method `astype` matches arguments
+ pandas/core/algorithms.py:556:34: error[no-matching-overload] No overload of bound method `astype` matches arguments
+ pandas/core/algorithms.py:556:34: error[no-matching-overload] No overload of bound method `astype` matches arguments
+ pandas/core/algorithms.py:587:18: error[no-matching-overload] No overload of bound method `astype` matches arguments
+ pandas/core/algorithms.py:587:18: error[no-matching-overload] No overload of bound method `astype` matches arguments
+ pandas/core/algorithms.py:587:18: error[no-matching-overload] No overload of bound method `astype` matches arguments
- pandas/core/algorithms.py:591:27: error[invalid-argument-type] Argument to function `ismember` is incorrect: Expected `ndarray[tuple[Any, ...], dtype[Any]]`, found `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | Index | ... omitted 5 union elements`
+ pandas/core/algorithms.py:591:27: error[invalid-argument-type] Argument to function `ismember` is incorrect: Expected `ndarray[tuple[Any, ...], dtype[Any]]`, found `ExtensionArray | ndarray[tuple[Any, ...], dtype[Any]] | (Index & ~MultiIndex) | ... omitted 4 union elements`
+ pandas/core/arrays/datetimelike.py:2585:71: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- pandas/core/arrays/period.py:1469:12: error[invalid-return-type] Return type does not match returned value: expected `tuple[ndarray[tuple[Any, ...], dtype[Any]], BaseOffset]`, found `tuple[ndarray[tuple[Any, ...], dtype[Any]], BaseOffset | Unknown | None]`
+ pandas/core/arrays/period.py:1469:12: error[invalid-return-type] Return type does not match returned value: expected `tuple[ndarray[tuple[Any, ...], dtype[Any]], BaseOffset]`, found `tuple[ndarray[tuple[Any, ...], dtype[Unknown]], BaseOffset | Unknown | None]`
- pandas/core/sorting.py:428:16: error[invalid-return-type] Return type does not match returned value: expected `ndarray[tuple[Any, ...], dtype[signedinteger[_64Bit]]]`, found `ndarray[tuple[Any, ...], dtype[signedinteger[_64Bit]]] | Series | ndarray[tuple[Any, ...], dtype[Any]]`
+ pandas/core/sorting.py:428:16: error[invalid-return-type] Return type does not match returned value: expected `ndarray[tuple[Any, ...], dtype[signedinteger[_64Bit]]]`, found `ndarray[tuple[Any, ...], dtype[Any]] | ndarray[tuple[Any, ...], dtype[signedinteger[_64Bit]]] | Series`
- Found 3736 diagnostics
+ Found 3737 diagnostics

static-frame (https://github.com/static-frame/static-frame)
- static_frame/core/bus.py:671:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemLocReduces[Bus[Any], object_]`, found `InterGetItemLocReduces[Bus[Any] | TypeBlocks | Batch | ... omitted 7 union elements, object_]`
+ static_frame/core/bus.py:671:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemLocReduces[Bus[Any], object_]`, found `InterGetItemLocReduces[Top[Index[Any]] | Top[Series[Any, Any]] | TypeBlocks | ... omitted 6 union elements, object_]`
- static_frame/core/bus.py:675:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Bus[Any], object_]`, found `InterGetItemILocReduces[Bus[Any] | Top[Index[Any]] | TypeBlocks | ... omitted 7 union elements, generic[object]]`
+ static_frame/core/bus.py:675:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Bus[Any], object_]`, found `InterGetItemILocReduces[Top[Index[Any]] | TypeBlocks | Top[Bus[Any]] | ... omitted 6 union elements, generic[object]]`
+ static_frame/core/index.py:580:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemLocReduces[TVContainer_co@loc, TVDtype@Index]`, found `InterGetItemLocReduces[Top[Series[Any, Any]] | Any, TVDtype@Index]`
- static_frame/core/index.py:763:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceString[ndarray[Any, Any]]`, found `InterfaceString[ndarray[Any, Any] | Bottom[Series[Any, Any]]]`
+ static_frame/core/index.py:763:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceString[ndarray[Any, Any]]`, found `InterfaceString[ndarray[object, object] | Bottom[Series[Any, Any]]]`
- static_frame/core/index.py:781:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceDatetime[ndarray[Any, Any]]`, found `InterfaceDatetime[ndarray[Any, Any] | Bottom[Series[Any, Any]]]`
+ static_frame/core/index.py:781:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceDatetime[ndarray[Any, Any]]`, found `InterfaceDatetime[ndarray[object, object] | Bottom[Series[Any, Any]]]`
- static_frame/core/index.py:801:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceRe[ndarray[Any, Any]]`, found `InterfaceRe[ndarray[Any, Any] | Bottom[Series[Any, Any]]]`
+ static_frame/core/index.py:801:16: error[invalid-return-type] Return type does not match returned value: expected `InterfaceRe[ndarray[Any, Any]]`, found `InterfaceRe[ndarray[object, object] | Bottom[Series[Any, Any]]]`
+ static_frame/core/node_selector.py:526:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemLocReduces[TVContainer_co@InterfaceSelectQuartet, Any]`, found `InterGetItemLocReduces[Top[Series[Any, Any]] | Unknown, Any]`
- static_frame/core/series.py:772:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Series[Any, Any], TVDtype@Series]`, found `InterGetItemILocReduces[Series[Any, Any] | Top[Index[Any]] | TypeBlocks | ... omitted 6 union elements, generic[object]]`
+ static_frame/core/series.py:772:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Series[Any, Any], TVDtype@Series]`, found `InterGetItemILocReduces[Series[Any, Any] | TypeBlocks | Batch | ... omitted 6 union elements, generic[object]]`
- static_frame/core/series.py:4072:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[SeriesHE[Any, Any], TVDtype@SeriesHE]`, found `InterGetItemILocReduces[SeriesHE[Any, Any] | Top[Index[Any]] | TypeBlocks | ... omitted 7 union elements, generic[object]]`
+ static_frame/core/series.py:4072:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[SeriesHE[Any, Any], TVDtype@SeriesHE]`, found `InterGetItemILocReduces[Bottom[Series[Any, Any]] | TypeBlocks | Batch | ... omitted 7 union elements, generic[object]]`
- static_frame/core/yarn.py:418:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Yarn[Any], object_]`, found `InterGetItemILocReduces[Yarn[Any] | Top[Index[Any]] | TypeBlocks | ... omitted 7 union elements, generic[object]]`
+ static_frame/core/yarn.py:418:16: error[invalid-return-type] Return type does not match returned value: expected `InterGetItemILocReduces[Yarn[Any], object_]`, found `InterGetItemILocReduces[Top[Yarn[Any]] | TypeBlocks | Batch | ... omitted 6 union elements, generic[object]]`
- static_frame/test/unit/test_series.py:4489:37: error[no-matching-overload] No overload of function `round` matches arguments
- Found 1839 diagnostics
+ Found 1840 diagnostics

pandas-stubs (https://github.com/pandas-dev/pandas-stubs)
+ tests/indexes/test_indexes.py:533:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int]]` does not match asserted type `Unknown`
- tests/indexes/test_indexes.py:541:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int | float]]` does not match asserted type `IntervalIndex[Interval[int]]`
+ tests/indexes/test_indexes.py:541:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int | float]]` does not match asserted type `Unknown`
+ tests/indexes/test_indexes.py:644:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int]]` does not match asserted type `Unknown`
- tests/indexes/test_indexes.py:655:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int | float]]` does not match asserted type `IntervalIndex[Interval[int]]`
+ tests/indexes/test_indexes.py:655:9: error[type-assertion-failure] Type `IntervalIndex[Interval[int | float]]` does not match asserted type `Unknown`
- tests/test_timefuncs.py:1464:9: error[type-assertion-failure] Type `DatetimeIndex` does not match asserted type `Unknown`
- Found 5085 diagnostics
+ Found 5086 diagnostics

core (https://github.com/home-assistant/core)
- homeassistant/components/tado/climate.py:813:20: error[unsupported-operator] Operator `in` is not supported between objects of type `str | None` and `@Todo | str | list[Unknown]`
- homeassistant/core.py:1668:33: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `(Event[Mapping[str, Any]], /) -> Coroutine[Any, Any, None] | None`, found `(Event[_DataT@async_listen_once], /) -> Coroutine[Any, Any, None] | None`
- homeassistant/util/variance.py:47:12: error[invalid-return-type] Return type does not match returned value: expected `(**_P@ignore_variance) -> _R@ignore_variance`, found `_Wrapped[_P@ignore_variance, _R@ignore_variance | int | float | datetime, _P@ignore_variance, _R@ignore_variance | int | float | datetime]`
- Found 14415 diagnostics
+ Found 14412 diagnostics

No memory usage changes detected ✅

astral-sh-bot · 2025-12-19T04:35:23Z

`ecosystem-analyzer` results

Lint rule	Added	Removed	Changed
`invalid-return-type`	4	1	22
`invalid-assignment`	0	0	23
`invalid-argument-type`	6	4	10
`no-matching-overload`	6	3	0
`possibly-missing-attribute`	2	6	0
`type-assertion-failure`	2	1	2
`unused-ignore-comment`	3	0	0
`non-subscriptable`	1	0	0
`unsupported-operator`	0	1	0
Total	24	16	57

Full report with detailed diff (timing results)

AlexWaygood

Makes sense to me!

ibraheemdev · 2025-12-19T22:27:26Z

This seems to have a mixed ecosystem impact, which is somewhat unavoidable given any heuristic. Given that the impact is relatively small, and this becomes more important after #21930 (where we are able to infer a lot more type context from covariant types), I'm going to go ahead and merge this. Some of the regressions may also be improved by the new constraint solver.

AlexWaygood · 2025-12-19T23:02:28Z

That was my conclusion from skimming through the ecosystem diff too, yeah

ref: astral-sh#22068

ibraheemdev requested review from AlexWaygood and carljm as code owners December 19, 2025 04:24

ibraheemdev added the ty Multi-file analysis & type inference label Dec 19, 2025

ibraheemdev requested review from dcreager and sharkdp as code owners December 19, 2025 04:24

only prefer declared types in non-covariant positions

ad842fd

ibraheemdev force-pushed the ibraheem/prefer-non-covariant-declared-types branch from 649efd4 to ad842fd Compare December 19, 2025 04:28

ibraheemdev added the ecosystem-analyzer label Dec 19, 2025

AlexWaygood approved these changes Dec 19, 2025

View reviewed changes

ibraheemdev merged commit 674d390 into main Dec 19, 2025
43 checks passed

ibraheemdev deleted the ibraheem/prefer-non-covariant-declared-types branch December 19, 2025 22:27

mtshiba added a commit to mtshiba/ruff that referenced this pull request Dec 23, 2025

don't use return type context to specialize __init__ type variables

800bfc8

ref: astral-sh#22068

mtshiba added a commit to mtshiba/ruff that referenced this pull request Dec 23, 2025

don't use return type context to specialize __init__ type variables

0a80f98

ref: astral-sh#22068

mtshiba mentioned this pull request Dec 23, 2025

[ty] infer function's return type #17371

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[ty] Only prefer declared types in non-covariant positions#22068

[ty] Only prefer declared types in non-covariant positions#22068
ibraheemdev merged 1 commit intomainfrom
ibraheem/prefer-non-covariant-declared-types

ibraheemdev commented Dec 19, 2025

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ibraheemdev commented Dec 19, 2025

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Diagnostic diff on typing conformance tests

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