Use checkmember.py to check variable overrides #18847

ilevkivskyi · 2025-03-28T00:53:15Z

Fixes #5803
Fixes #18695
Fixes #17513
Fixes #13194
Fixes #12126

This is the first PR towards #7724, some notes:

I add a new generic suppress_errors flag to MemberContext mostly as a performance optimization, but it should also be handy in the following PRs
I noticed some inconsistencies with how we handle variable inference (e.g. we don't infer type at all if rvalue type is not compatible with superclass type). After all I decided to remove some of them, as it makes implementation of this PR simpler.
I added a bunch of TODOs, most of those will be addressed in following PRs.
A while ago we agreed that an explicit Callable[...] annotation in class body means how the type looks on an instance, but the override check used to handle this inconsistently (I add few reveal_type()s to tests to illustrate this).

ilevkivskyi · 2025-03-28T01:34:48Z

Looking at the primer, something is wrong with the class objects as r.h.s., I will check tomorrow.

ilevkivskyi · 2025-03-29T21:15:29Z

@JukkaL I think this is ready for review, I spot-checked most of the primer and the results look good. There are some minor changes in semantics caused by moving override check to a single location after the variable type was inferred. Looking back at this now, it is actually not strictly necessary, but IMO it removes the coupling between override checks and inference, and so makes things more predictable and easier to reason about.

sterliakov · 2025-03-30T00:10:23Z

Fixes False positive violation when overriding attributes using descriptors #18695
improves Assignment to classvar narrows type seemingly too much #17981 (but doesn't fix the root problem)
fixes False positives when overriding attributes in superclasses defined with function definitions #17513
breaks Assigning wrapped class members to a member defined by a base class fails with incompatible types in assignment #14408 further (if I'm not mistaken)
fixes Assignment through def does not satisfy ABC's Optional Callable with args #13194 (current master has one false negative; OP presumed it to be valid, but it's not, lambda undergoes binding and mypy only understands that in overrides with this PR)
fixes Inconsistent errors when reassigning Union[list|Callable] in subclass #12126
fixes the specific example in functools.partialmethod not supported properly? #8619, but probably not the root problem

Are you still sure you don't want this check running for every PR as an informational non-blocker? :)

github-actions · 2025-03-30T09:23:16Z

Diff from mypy_primer, showing the effect of this PR on open source code:

comtypes (https://github.com/enthought/comtypes)
- comtypes/_post_coinit/unknwn.py:303: error: Incompatible types in assignment (expression has type "property", base class "_SimpleCData" defined the type as "int | None")  [assignment]

manticore (https://github.com/trailofbits/manticore)
+ manticore/core/smtlib/solver.py:1050: error: Incompatible types in assignment (expression has type "SmtlibPortfolio", base class "SMTLIBSolver" defined the type as "SmtlibProc")  [assignment]

static-frame (https://github.com/static-frame/static-frame)
+ static_frame/core/archive_npy.py:305: error: Incompatible types in assignment (expression has type "Callable[[DefaultNamedArg(int | None, 'dir_fd')], None]", base class "Archive" defined the type as "Callable[[str | PathLike[Any]], None]")  [assignment]

pandas (https://github.com/pandas-dev/pandas)
+ pandas/io/common.py:995: error: No overload variant of "open" of "TarFile" matches argument types "str | None", "str", "ReadBuffer[bytes] | WriteBuffer[bytes] | None", "dict[str, Any]"  [call-overload]
+ pandas/io/common.py:995: note: Error code "call-overload" not covered by "type: ignore" comment
+ pandas/io/common.py:995: note: Possible overload variants:
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., mode: Literal['r', 'r:*', 'r:', 'r:gz', 'r:bz2', 'r:xz'] = ..., fileobj: _Fileobj | None = ..., bufsize: int = ..., *, format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None, mode: Literal['x', 'x:', 'a', 'a:', 'w', 'w:', 'w:tar'], fileobj: _Fileobj | None = ..., bufsize: int = ..., *, format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., *, mode: Literal['x', 'x:', 'a', 'a:', 'w', 'w:', 'w:tar'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None, mode: Literal['x:gz', 'x:bz2', 'w:gz', 'w:bz2'], fileobj: _Fileobj | None = ..., bufsize: int = ..., *, format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ..., compresslevel: int = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., *, mode: Literal['x:gz', 'x:bz2', 'w:gz', 'w:bz2'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ..., compresslevel: int = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None, mode: Literal['x:xz', 'w:xz'], fileobj: _Fileobj | None = ..., bufsize: int = ..., *, format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ..., preset: Literal[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | None = ..., *, mode: Literal['x:xz', 'w:xz'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ..., preset: Literal[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | Buffer | None = ..., *, mode: Literal['r|*', 'r|', 'r|gz', 'r|bz2', 'r|xz'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | Buffer | None = ..., *, mode: Literal['w|', 'w|xz'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ...) -> TarFile
+ pandas/io/common.py:995: note:     def open(cls, name: str | bytes | PathLike[str] | PathLike[bytes] | Buffer | None = ..., *, mode: Literal['w|gz', 'w|bz2'], fileobj: _Fileobj | None = ..., bufsize: int = ..., format: int | None = ..., tarinfo: type[TarInfo] | None = ..., dereference: bool | None = ..., ignore_zeros: bool | None = ..., encoding: str | None = ..., errors: str = ..., pax_headers: Mapping[str, str] | None = ..., debug: int | None = ..., errorlevel: int | None = ..., compresslevel: int = ...) -> TarFile
+ pandas/io/common.py:1050: error: No overload variant of "ZipFile" matches argument types "str | PathLike[str] | ReadBuffer[bytes] | WriteBuffer[bytes]", "str", "dict[str, Any]"  [call-overload]
+ pandas/io/common.py:1050: note: Error code "call-overload" not covered by "type: ignore" comment
+ pandas/io/common.py:1050: note: Possible overload variants:
+ pandas/io/common.py:1050: note:     def __init__(self, file: str | PathLike[str] | IO[bytes], mode: Literal['r', 'w', 'x', 'a'] = ..., compression: int = ..., allowZip64: bool = ..., compresslevel: int | None = ..., *, strict_timestamps: bool = ..., metadata_encoding: str | None = ...) -> ZipFile
+ pandas/io/common.py:1050: note:     def __init__(self, file: str | PathLike[str] | _ZipReadable, mode: Literal['r'] = ..., compression: int = ..., allowZip64: bool = ..., compresslevel: int | None = ..., *, strict_timestamps: bool = ..., metadata_encoding: str | None = ...) -> ZipFile
+ pandas/io/common.py:1050: note:     def __init__(self, file: str | PathLike[str] | _ZipWritable, mode: Literal['w', 'x'] = ..., compression: int = ..., allowZip64: bool = ..., compresslevel: int | None = ..., *, strict_timestamps: bool = ..., metadata_encoding: None = ...) -> ZipFile
+ pandas/io/common.py:1050: note:     def __init__(self, file: str | PathLike[str] | _ZipReadableTellable, mode: Literal['a'] = ..., compression: int = ..., allowZip64: bool = ..., compresslevel: int | None = ..., *, strict_timestamps: bool = ..., metadata_encoding: None = ...) -> ZipFile
+ pandas/core/arrays/period.py:183: error: Incompatible types in assignment (expression has type "Callable[[], bool]", base class "DatetimeLikeArrayMixin" defined the type as "Callable[[dtype[Any] | ExtensionDtype], bool]")  [assignment]
+ pandas/core/arrays/timedeltas.py:150: error: Incompatible types in assignment (expression has type "Callable[[], bool]", base class "DatetimeLikeArrayMixin" defined the type as "Callable[[dtype[Any] | ExtensionDtype], bool]")  [assignment]
+ pandas/core/arrays/datetimes.py:229: error: Incompatible types in assignment (expression has type "Callable[[], bool]", base class "DatetimeLikeArrayMixin" defined the type as "Callable[[dtype[Any] | ExtensionDtype], bool]")  [assignment]
+ pandas/core/arrays/integer.py:29: error: Incompatible types in assignment (expression has type "Callable[[], bool]", base class "NumericDtype" defined the type as "Callable[[Any], bool]")  [assignment]
+ pandas/core/arrays/floating.py:29: error: Incompatible types in assignment (expression has type "Callable[[], bool]", base class "NumericDtype" defined the type as "Callable[[Any], bool]")  [assignment]
+ pandas/core/indexes/frozen.py:75: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/indexes/frozen.py:120: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/indexes/frozen.py:123: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/series.py:356: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/reshape/merge.py:2183: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/reshape/merge.py:2184: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/indexes/multi.py:3940: error: Unused "type: ignore" comment  [unused-ignore]
+ pandas/core/reshape/reshape.py:355: error: Unused "type: ignore" comment  [unused-ignore]

werkzeug (https://github.com/pallets/werkzeug)
+ src/werkzeug/datastructures/headers.py:625: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:534: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:542: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:545: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:547: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:550: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:551: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:554: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:558: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:559: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:560: error: Unused "type: ignore" comment  [unused-ignore]
+ src/werkzeug/local.py:571: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/test_wrappers.py:1004: error: Incompatible types in assignment (expression has type "type[_ImmutableOrderedMultiDict[K, V]]", base class "Request" defined the type as "type[MultiDict[str, Any]]")  [assignment]
- tests/test_wrappers.py:1036: error: Incompatible types in assignment (expression has type "type[dict[Any, Any]]", base class "Request" defined the type as "type[MultiDict[str, Any]]")  [assignment]
+ tests/test_wrappers.py:1036: error: Incompatible types in assignment (expression has type "type[dict[_KT, _VT]]", base class "Request" defined the type as "type[MultiDict[str, Any]]")  [assignment]
- tests/test_wrappers.py:1038: error: Incompatible types in assignment (expression has type "type[dict[Any, Any]]", base class "Request" defined the type as "type[MultiDict[str, Any]]")  [assignment]
+ tests/test_wrappers.py:1038: error: Incompatible types in assignment (expression has type "type[dict[_KT, _VT]]", base class "Request" defined the type as "type[MultiDict[str, Any]]")  [assignment]
- tests/test_routing.py:733: error: Cannot determine type of "default_converters"  [has-type]
- tests/test_local.py:149: error: Cannot determine type of "__eq__"  [has-type]
- tests/test_local.py:189: error: Cannot determine type of "__doc__"  [has-type]
- tests/test_local.py:200: error: Cannot determine type of "__class__"  [has-type]
- tests/test_local.py:201: error: Cannot determine type of "__doc__"  [has-type]

steam.py (https://github.com/Gobot1234/steam.py)
- steam/trade.py:317: error: Cannot determine type of "REPR_ATTRS"  [has-type]
+ steam/trade.py:317: error: Incompatible types in assignment (expression has type "tuple[str, str, str, str, str, str, str, str, str, str]", base class "Item" defined the type as "tuple[str, str, str, str, str, str, str, str]")  [assignment]
+ steam/_gc/client.py:47: error: Unused "type: ignore" comment  [unused-ignore]
- steam/ext/csgo/backpack.py:291: error: Cannot determine type of "REPR_ATTRS"  [has-type]
+ steam/ext/csgo/backpack.py:291: error: Incompatible types in assignment (expression has type "tuple[str, str, str, str, str, str, str, str, str]", base class "Item" defined the type as "tuple[str, str, str, str, str, str, str, str]")  [assignment]
+ steam/ext/csgo/backpack.py:358: error: Incompatible types in assignment (expression has type "tuple[str, str, str, str, str, str, str, str, str, str]", base class "BackpackItem" defined the type as "tuple[str, str, str, str, str, str, str, str, str]")  [assignment]
- steam/ext/tf2/backpack.py:80: error: Cannot determine type of "REPR_ATTRS"  [has-type]
+ steam/ext/tf2/backpack.py:80: error: Incompatible types in assignment (expression has type "tuple[str, str, str, str, str, str, str, str, str, str]", base class "Item" defined the type as "tuple[str, str, str, str, str, str, str, str]")  [assignment]

sympy (https://github.com/sympy/sympy)
+ sympy/core/containers.py:334: error: Incompatible types in assignment (expression has type "Callable[[Basic], Any]", base class "Basic" defined the type as "Callable[[], int]")  [assignment]
+ sympy/sets/sets.py:2186: error: Incompatible types in assignment (expression has type "Callable[[Basic], Any]", base class "Basic" defined the type as "Callable[[], int]")  [assignment]
+ sympy/matrices/expressions/diagonal.py:52: error: Unused "type: ignore" comment  [unused-ignore]
+ sympy/matrices/expressions/fourier.py:49: error: Unused "type: ignore" comment  [unused-ignore]
+ sympy/matrices/expressions/fourier.py:50: error: Unused "type: ignore" comment  [unused-ignore]
+ sympy/matrices/expressions/factorizations.py:6: error: Unused "type: ignore" comment  [unused-ignore]
+ sympy/physics/biomechanics/musculotendon.py:1416: error: Incompatible types in assignment (expression has type "CharacteristicCurveCollection", base class "MusculotendonBase" defined the type as "Callable[[], Any]")  [assignment]

freqtrade (https://github.com/freqtrade/freqtrade)
+ freqtrade/persistence/trade_model.py:1646: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1650: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1655: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1656: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1657: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1658: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1659: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1660: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1661: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1662: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1665: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1668: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1669: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1672: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1673: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1677: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1678: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1679: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1680: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1683: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1684: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1685: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1686: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1687: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1688: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1689: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1692: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1694: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1696: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1698: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1702: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1705: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1709: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1713: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1714: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1717: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1720: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1721: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1724: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1726: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1729: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1732: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1733: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1734: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1737: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1740: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1741: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1742: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1747: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1752: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1755: error: Unused "type: ignore" comment  [unused-ignore]
+ freqtrade/persistence/trade_model.py:1759: error: Unused "type: ignore" comment  [unused-ignore]

jinja (https://github.com/pallets/jinja)
+ src/jinja2/nativetypes.py:108: error: Unused "type: ignore" comment  [unused-ignore]
+ src/jinja2/nativetypes.py:123: error: Unused "type: ignore" comment  [unused-ignore]

antidote (https://github.com/Finistere/antidote)
+ tests/core/test_inject_wrapper.py:246: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/core/test_inject_wrapper.py:252: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/core/test_inject_wrapper.py:258: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/core/test_inject_wrapper.py:354: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/core/test_inject_wrapper.py:360: error: Unused "type: ignore" comment  [unused-ignore]
+ tests/core/test_inject_wrapper.py:366: error: Unused "type: ignore" comment  [unused-ignore]

django-stubs (https://github.com/typeddjango/django-stubs)
+ django-stubs/db/models/fields/related.pyi:245: error: Incompatible types in assignment (expression has type "Union[str, _StrPromise]", base class "Field" defined the type as "str")  [assignment]

scrapy (https://github.com/scrapy/scrapy)
+ tests/test_spidermiddleware_referer.py:1047: error: Incompatible types in assignment (expression has type "list[tuple[str, str, tuple[tuple[int, str], ...], None, None]]", base class "TestReferrerOnRedirect" defined the type as "list[tuple[str, str, tuple[tuple[int, str], ...], bytes | None, bytes | None]]")  [assignment]
+ tests/test_spidermiddleware_referer.py:1047: note: "list" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
+ tests/test_spidermiddleware_referer.py:1047: note: Consider using "Sequence" instead, which is covariant
+ tests/test_spidermiddleware_referer.py:1086: error: Incompatible types in assignment (expression has type "list[tuple[str, str, tuple[tuple[int, str], ...], bytes, bytes | None]]", base class "TestReferrerOnRedirect" defined the type as "list[tuple[str, str, tuple[tuple[int, str], ...], bytes | None, bytes | None]]")  [assignment]
+ tests/test_spidermiddleware_referer.py:1086: note: "list" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
+ tests/test_spidermiddleware_referer.py:1086: note: Consider using "Sequence" instead, which is covariant
+ tests/test_spidermiddleware_referer.py:1207: error: Incompatible types in assignment (expression has type "list[tuple[str, str, tuple[tuple[int, str], ...], bytes, bytes]]", base class "TestReferrerOnRedirect" defined the type as "list[tuple[str, str, tuple[tuple[int, str], ...], bytes | None, bytes | None]]")  [assignment]
+ tests/test_spidermiddleware_referer.py:1207: note: "list" is invariant -- see https://mypy.readthedocs.io/en/stable/common_issues.html#variance
+ tests/test_spidermiddleware_referer.py:1207: note: Consider using "Sequence" instead, which is covariant

ibis (https://github.com/ibis-project/ibis)
- ibis/backends/athena/__init__.py:279: error: Argument 1 to "Schema" has incompatible type "dict[Any, Any]"; expected "FrozenOrderedDict[str, DataType]"  [arg-type]
+ ibis/backends/athena/__init__.py:279: error: Argument 1 to "Schema" has incompatible type "dict[Any, DataType]"; expected "FrozenOrderedDict[str, DataType]"  [arg-type]
- ibis/backends/athena/__init__.py:280: error: Cannot determine type of "type_mapper"  [has-type]
- ibis/backends/athena/__init__.py:635: error: Cannot determine type of "type_mapper"  [has-type]
- ibis/backends/athena/__init__.py:637: error: Argument 1 to "Schema" has incompatible type "dict[Any, Any]"; expected "FrozenOrderedDict[str, DataType]"  [arg-type]
+ ibis/backends/athena/__init__.py:637: error: Argument 1 to "Schema" has incompatible type "dict[Any, DataType]"; expected "FrozenOrderedDict[str, DataType]"  [arg-type]

jax (https://github.com/google/jax)
+ jax/_src/prng.py:212: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:213: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:214: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:215: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:216: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:217: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/prng.py:218: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:58: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:59: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:62: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:63: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:64: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:70: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:72: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:73: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:74: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:75: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:76: error: Unused "type: ignore" comment  [unused-ignore]
+ jax/_src/earray.py:77: error: Unused "type: ignore" comment  [unused-ignore]

core (https://github.com/home-assistant/core)
- homeassistant/components/script/__init__.py:543: error: Incompatible types in assignment (expression has type "None", base class "Entity" defined the type as "Callable[[Entity], str | None]")  [assignment]
- homeassistant/components/script/__init__.py:556: error: Cannot determine type of "icon"  [has-type]
- homeassistant/components/tikteck/light.py:63: error: Incompatible types in assignment (expression has type "tuple[float, float]", base class "LightEntity" defined the type as "Callable[[LightEntity], tuple[float, float] | None]")  [assignment]
- homeassistant/components/tikteck/light.py:64: error: Incompatible types in assignment (expression has type "int", base class "LightEntity" defined the type as "Callable[[LightEntity], int | None]")  [assignment]
- homeassistant/components/zoneminder/switch.py:62: error: Incompatible types in assignment (expression has type "str", base class "Entity" defined the type as "Callable[[Entity], str | None]")  [assignment]
- homeassistant/components/xiaomi_miio/humidifier.py:176: error: Incompatible types in assignment (expression has type "list[str]", base class "HumidifierEntity" defined the type as "Callable[[HumidifierEntity], list[str] | None]")  [assignment]
- homeassistant/components/vlc_telnet/media_player.py:96: error: Incompatible types in assignment (expression has type "int", base class "MediaPlayerEntity" defined the type as "Callable[[MediaPlayerEntity], float | None]")  [assignment]
- homeassistant/components/moehlenhoff_alpha2/climate.py:42: error: Incompatible types in assignment (expression has type "float", base class "ClimateEntity" defined the type as "Callable[[ClimateEntity], float | None]")  [assignment]
- homeassistant/components/balboa/time.py:38: error: Incompatible types in assignment (expression has type "EntityCategory", base class "Entity" defined the type as "Callable[[Entity], EntityCategory | None]")  [assignment]
- homeassistant/components/vodafone_station/device_tracker.py:73: error: Incompatible types in assignment (expression has type "str", base class "ScannerEntity" defined the type as "Callable[[ScannerEntity], str | None]")  [assignment]
- homeassistant/components/hue/v1/sensor_base.py:171: error: Incompatible types in assignment (expression has type "bool", base class "Entity" defined the type as "Callable[[Entity], bool]")  [assignment]
- homeassistant/components/synology_dsm/entity.py:33: error: Incompatible types in assignment (expression has type "str", base class "Entity" defined the type as "Callable[[Entity], str | None]")  [assignment]
- homeassistant/components/roborock/image.py:46: error: Incompatible types in assignment (expression has type "datetime", base class "ImageEntity" defined the type as "Callable[[ImageEntity], datetime | None]")  [assignment]

asynq (https://github.com/quora/asynq)
+ asynq/decorators.pyi:104: error: Unused "type: ignore" comment  [unused-ignore]

bokeh (https://github.com/bokeh/bokeh)
+ release/action.py: note: In class "FAILED":
+ release/action.py:42:10: error: Incompatible types in assignment (expression has type "Callable[[Sequence[str] | None], str]", base class "ActionReturn" defined the type as "Callable[[str, Sequence[str] | None], str]")  [assignment]
+ release/action.py: note: In class "PASSED":
+ release/action.py:49:10: error: Incompatible types in assignment (expression has type "Callable[[Sequence[str] | None], str]", base class "ActionReturn" defined the type as "Callable[[str, Sequence[str] | None], str]")  [assignment]
+ release/action.py: note: In class "SKIPPED":
+ release/action.py:56:10: error: Incompatible types in assignment (expression has type "Callable[[Sequence[str] | None], str]", base class "ActionReturn" defined the type as "Callable[[str, Sequence[str] | None], str]")  [assignment]

pytest (https://github.com/pytest-dev/pytest)
+ src/_pytest/python_api.py:466: error: Unused "type: ignore" comment  [unused-ignore]

ilevkivskyi · 2025-03-30T09:59:30Z

@sterliakov I still think it should be run on-demand, i.e. I want to be able to trigger a run on PRs where I expect significant fallout (like this one). This can be done using workflow_dispatch (example of how it is done in typeshed stub uploader https://github.com/typeshed-internal/stub_uploader/blob/main/.github/workflows/force_update.yml#L3-L8)

Btw few comments on the issues:

Assigning wrapped class members to a member defined by a base class fails with incompatible types in assignment #14408 should not be getting worse with the latest commit.
Assignment to classvar narrows type seemingly too much #17981 is an example of inconsistency I mentioned above to @JukkaL. I would even say this PR is a proper fix, IMO mypy should narrow type in subclasses (as it currently does), this PR simply makes this behavior more uniform/consistent.

sterliakov · 2025-03-30T15:32:46Z

workflow_dispatch is possible, but has one big drawback: only repo owners (or at least those with write access) can dispatch such workflows. So I won't be able to run that workflow myself. The semi-canonical solution to on-demand checks is a simple workflow on issue_comment with /pull/ source (so you can comment /check-issues on a PR to run, that's almost exactly what I'm doing in that repo) or a home-grown bot (like bedevere-app in core CPython or rustbot in rust-lang), but the latter is probably overkill for such a simple task. (But let's move this discussion out of this PR, I'll create a separate issue)

As for #17981, my personal preference would be to not narrow in subclasses fields explicitly annotated in superclass (but allow explicit narrowing with annotation), but this may not align with your vision. This would help me remove a few redundant annotations in class hierarchies. This PR at least improves handling of such cases, eliminating the strange "cannot determine type" error.

And could you edit "fixes" issues into PR description to close everything upon merging automatically?

JukkaL

Looks good, love to see so many type ignore comments that are now redundant.

Use checkmember.py to check variable overrides

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ilevkivskyi requested a review from JukkaL March 28, 2025 00:53

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Update test

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Try more principled approach

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Handle operators consistently

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Try more principled approach to method override inference

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JukkaL approved these changes Mar 31, 2025

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ilevkivskyi merged commit 4629de4 into python:master Mar 31, 2025
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ilevkivskyi deleted the use-checkmember-subtype-var branch March 31, 2025 13:46

ilevkivskyi mentioned this pull request Mar 31, 2025

Assignment to classvar narrows type seemingly too much #17981

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Use checkmember.py to check variable overrides #18847

Use checkmember.py to check variable overrides #18847

ilevkivskyi commented Mar 28, 2025 •

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Use checkmember.py to check variable overrides #18847

Use checkmember.py to check variable overrides #18847

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