Use TypeVar defaults when inferring from a type object - #22044
Open
Dextheking1 wants to merge 1 commit into
Open
Dextheking1 wants to merge 1 commit into
Dextheking1 wants to merge 1 commit into
Conversation
Contributor
|
Diff from mypy_primer, showing the effect of this PR on open source code: psycopg (https://github.com/psycopg/psycopg)
+ psycopg/psycopg/connection_async.py:82: error: Incompatible types in assignment (expression has type "type[AsyncCursor[tuple[Any, ...]]]", variable has type "type[AsyncCursor[Row]]") [assignment]
+ psycopg/psycopg/connection_async.py:83: error: Incompatible types in assignment (expression has type "type[AsyncServerCursor[tuple[Any, ...]]]", variable has type "type[AsyncServerCursor[Row]]") [assignment]
+ psycopg/psycopg/connection.py:78: error: Incompatible types in assignment (expression has type "type[Cursor[tuple[Any, ...]]]", variable has type "type[Cursor[Row]]") [assignment]
+ psycopg/psycopg/connection.py:79: error: Incompatible types in assignment (expression has type "type[ServerCursor[tuple[Any, ...]]]", variable has type "type[ServerCursor[Row]]") [assignment]
steam.py (https://github.com/Gobot1234/steam.py)
+ steam/profile.py:157: error: Argument 1 to "dataclass" has incompatible type "type[OwnedProfileItems[UserT]]"; expected "type[OwnedProfileItems[User]]" [arg-type]
+ steam/profile.py:173: error: Argument 1 to "dataclass" has incompatible type "type[EquippedProfileItems[UserT]]"; expected "type[EquippedProfileItems[User]]" [arg-type]
+ steam/profile.py:189: error: Argument 1 has incompatible type "type[ProfileShowcaseSlot[UserT]]"; expected "type[ProfileShowcaseSlot[User]]" [arg-type]
+ steam/profile.py:268: error: Argument 1 has incompatible type "type[ProfileShowcase[UserT]]"; expected "type[ProfileShowcase[User]]" [arg-type]
+ steam/leaderboard.py:72: error: Argument 1 has incompatible type "type[Leaderboard[AppT, DisplayNameT]]"; expected "type[Leaderboard[Any, None]]" [arg-type]
+ steam/gateway.py:95: error: Argument 1 has incompatible type "type[EventListener[MsgsT]]"; expected "type[EventListener[ProtobufMessage | Message | GCProtobufMessage | GCMessage]]" [arg-type]
+ steam/gateway.py:105: error: Argument 1 has incompatible type "type[GCEventListener[GCMsgsT]]"; expected "type[GCEventListener[GCProtobufMessage | GCMessage]]" [arg-type]
- steam/ext/commands/commands.py:709: error: Incompatible default for parameter "cls" (default has type "type[Command[Any, Any, Any]]", parameter has type "type[C]") [assignment]
+ steam/ext/commands/commands.py:709: error: Incompatible default for parameter "cls" (default has type "type[Command[Cog[Bot] | Bot | None, [VarArg(Any), KwArg(Any)], Any]]", parameter has type "type[C]") [assignment]
- steam/ext/commands/commands.py:807: error: Incompatible default for parameter "cls" (default has type "type[Command[Any, Any, Any]]", parameter has type "type[C]") [assignment]
+ steam/ext/commands/commands.py:807: error: Incompatible default for parameter "cls" (default has type "type[Command[Cog[Bot] | Bot | None, [VarArg(Any), KwArg(Any)], Any]]", parameter has type "type[C]") [assignment]
- steam/ext/commands/commands.py:831: error: Incompatible return value type (got "C | Command[Any, Any, Any]", expected "C") [return-value]
+ steam/ext/commands/commands.py:831: error: Incompatible return value type (got "Command[Cog[Bot] | Bot | None, [VarArg(Any), KwArg(Any)], Any]", expected "C") [return-value]
- steam/ext/commands/bot.py:519: error: Incompatible default for parameter "cls" (default has type "type[Context[Any]]", parameter has type "type[C]") [assignment]
+ steam/ext/commands/bot.py:519: error: Incompatible default for parameter "cls" (default has type "type[Context[Bot]]", parameter has type "type[C]") [assignment]
pandas-stubs (https://github.com/pandas-dev/pandas-stubs)
+ tests/series/test_truediv.py:155: error: Expression is of type "Any", not "Never" [assert-type]
+ tests/series/test_truediv.py:195: error: Expression is of type "Any", not "Never" [assert-type]
+ tests/series/test_truediv.py:205: error: Expression is of type "Any", not "Never" [assert-type]
+ tests/series/test_sub.py:263: error: Expression is of type "Any", not "Series[Timedelta]" [assert-type]
+ tests/series/test_floordiv.py:135: error: Expression is of type "Any", not "Never" [assert-type]
+ tests/series/test_floordiv.py:171: error: Expression is of type "Any", not "Never" [assert-type]
+ tests/series/test_floordiv.py:180: error: Expression is of type "Series[Any]", not "Series[Timedelta]" [assert-type]
+ tests/indexes/test_indexes.py:1796: error: Unused "type: ignore" comment [unused-ignore]
+ tests/arrays/test_datetime_array.py:354: error: Expression is of type "Any", not "DatetimeArray" [assert-type]
pytest (https://github.com/pytest-dev/pytest)
+ testing/test_runner.py:140: error: Item "Exception" of "Exception | ExceptionGroup[Exception]" has no attribute "exceptions" [union-attr]
+ testing/test_runner.py:141: error: Item "Exception" of "Exception | ExceptionGroup[Exception]" has no attribute "exceptions" [union-attr]
jax (https://github.com/google/jax)
- jax/experimental/pallas/ops/tpu/splash_attention/splash_attention_mask_info.py:729: error: Incompatible types in assignment (expression has type "ndarray[tuple[Any, ...], dtype[bool[Any]]]", variable has type "list[ndarray[tuple[Any, ...], dtype[Any]]] | None") [assignment]
+ jax/experimental/pallas/ops/tpu/splash_attention/splash_attention_mask_info.py:729: error: Incompatible types in assignment (expression has type "ndarray[tuple[Any, ...], dtype[numpy.bool[builtins.bool]]]", variable has type "list[ndarray[tuple[Any, ...], dtype[Any]]] | None") [assignment]
static-frame (https://github.com/static-frame/static-frame)
+ static_frame/core/store_zip.py:49: error: Argument 1 has incompatible type "type[PayloadBytesToFrame[TVStoreConfig]]"; expected "type[PayloadBytesToFrame[StoreConfigBase]]" [arg-type]
+ static_frame/core/store_zip.py:60: error: Argument 1 has incompatible type "type[PayloadFrameToBytes[TVStoreConfig]]"; expected "type[PayloadFrameToBytes[StoreConfigBase]]" [arg-type]
scipy-stubs (https://github.com/scipy/scipy-stubs)
+ scipy-stubs/stats/_resampling.pyi:38: error: Argument 1 to "dataclass" has incompatible type "type[BootstrapResult[_FloatNDT, _DistT]]"; expected "type[BootstrapResult[Any, ndarray[tuple[Any, ...], dtype[float64]]]]" [arg-type]
+ scipy-stubs/stats/_resampling.pyi:44: error: Argument 1 to "dataclass" has incompatible type "type[PermutationTestResult[_FloatNDT, _DistT]]"; expected "type[PermutationTestResult[Any, ndarray[tuple[Any, ...], dtype[float64]]]]" [arg-type]
+ scipy-stubs/stats/_resampling.pyi:51: error: Argument 1 to "dataclass" has incompatible type "type[MonteCarloTestResult[_FloatNDT, _DistT]]"; expected "type[MonteCarloTestResult[Any, ndarray[tuple[Any, ...], dtype[float64]]]]" [arg-type]
+ scipy-stubs/stats/_multicomp.pyi:28: error: Argument 1 to "dataclass" has incompatible type "type[DunnettResult[_StatT_co]]"; expected "type[DunnettResult[float64]]" [arg-type]
+ scipy-stubs/stats/_stats_py.pyi:249: error: Argument 1 to "dataclass" has incompatible type "type[AlexanderGovernResult[_FloatOrArrayT_co]]"; expected "type[AlexanderGovernResult[float | ndarray[tuple[Any, ...], dtype[float64]]]]" [arg-type]
+ scipy-stubs/stats/_stats_py.pyi:262: error: Argument 1 to "dataclass" has incompatible type "type[QuantileTestResult[_FloatT]]"; expected "type[QuantileTestResult[float64 | Any]]" [arg-type]
+ scipy-stubs/stats/_survival.pyi:35: error: Argument 1 to "dataclass" has incompatible type "type[EmpiricalDistributionFunction[_QuantileT_co]]"; expected "type[EmpiricalDistributionFunction[float64]]" [arg-type]
+ scipy-stubs/stats/_survival.pyi:55: error: Argument 1 to "dataclass" has incompatible type "type[ECDFResult[_QuantileT_co]]"; expected "type[ECDFResult[float64]]" [arg-type]
|
Dextheking1
marked this pull request as ready for review
October 2, 2026 00:13
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Fixes #21608.
When a generic class with TypeVar defaults is passed where
type[S]is expected, mypy inferredAnyfor the defaulted parameters instead of using the defaults. For example, withdef f(x: type[S]) -> S,f(Box)gaveBox[Any]instead ofBox[int | None].The class object type was erased with
erase_typevars, which replaces every type variable withAny. I addederase_typevars_with_defaultsin erasetype.py, which substitutes each type variable's default when it has one (defaults referencing earlier type variables are expanded gradually, like typeanal does) and falls back toAnyotherwise. It is now used in the two places where a type object gets erased for atype[...]context:analyze_ref_exprin checkexpr.py andvisit_type_typein constraints.py.This matches how a bare generic already behaves in annotations:
x: type[Box] = Boxrevealstype[Box[int | None]].Added a regression test in check-typevar-defaults.test. It fails on master and passes with the fix. Full testcheck suite passes (8227 passed, 27 skipped, 7 xfailed). Self check on the touched files is clean.