[ty] Fix classmethod + contextmanager + Self

[eclbg]

Summary

The test I've added illustrates the fix. Copying it here too:

from contextlib import contextmanager
from typing import Iterator
from typing_extensions import Self

class Base:
    @classmethod
    @contextmanager
    def create(cls) -> Iterator[Self]:
        yield cls()

class Child(Base): ...

with Base.create() as base:
    reveal_type(base)  # revealed: Base (after the fix, None before)

with Child.create() as child:
    reveal_type(child)  # revealed: Child (after the fix, None before)

Full disclosure: I've used LLMs for this PR, but the result is thoroughly reviewed by me before submitting. I'm excited about my first Rust contribution to Astral tools and will address feedback quickly.

Related to astral-sh/ty#2030, I am working on a fix for the TypeVar case also reported in that issue (by me)

Test Plan

Updated mdtests

[astral-sh-bot]

Diagnostic diff on typing conformance tests

No changes detected when running ty on typing conformance tests ✅

[astral-sh-bot]

mypy_primer results

Changes were detected when running on open source projects

prefect (https://github.com/PrefectHQ/prefect)
- src/integrations/prefect-aws/prefect_aws/experimental/bundles/execute.py:52:10: warning[possibly-missing-attribute] Attribute `get_s3_client` may be missing on object of type `None | Coroutine[Any, Any, None] | AwsCredentials`
+ src/integrations/prefect-aws/prefect_aws/experimental/bundles/execute.py:52:10: warning[possibly-missing-attribute] Attribute `get_s3_client` may be missing on object of type `AwsCredentials | Coroutine[Any, Any, AwsCredentials]`
- src/integrations/prefect-aws/prefect_aws/experimental/bundles/upload.py:68:10: warning[possibly-missing-attribute] Attribute `get_s3_client` may be missing on object of type `None | Coroutine[Any, Any, None] | AwsCredentials`
+ src/integrations/prefect-aws/prefect_aws/experimental/bundles/upload.py:68:10: warning[possibly-missing-attribute] Attribute `get_s3_client` may be missing on object of type `AwsCredentials | Coroutine[Any, Any, AwsCredentials]`
- src/integrations/prefect-aws/tests/test_s3.py:1141:24: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `credentials`
+ src/integrations/prefect-aws/tests/test_s3.py:1141:24: warning[possibly-missing-attribute] Attribute `credentials` may be missing on object of type `S3Bucket | Coroutine[Any, Any, S3Bucket]`
- src/integrations/prefect-azure/prefect_azure/experimental/bundles/execute.py:28:19: error[invalid-await] `None | Coroutine[Any, Any, None]` is not awaitable
+ src/integrations/prefect-azure/prefect_azure/experimental/bundles/execute.py:28:19: error[invalid-await] `AzureBlobStorageCredentials | Coroutine[Any, Any, AzureBlobStorageCredentials]` is not awaitable
- src/integrations/prefect-azure/prefect_azure/experimental/bundles/upload.py:38:19: error[invalid-await] `None | Coroutine[Any, Any, None]` is not awaitable
+ src/integrations/prefect-azure/prefect_azure/experimental/bundles/upload.py:38:19: error[invalid-await] `AzureBlobStorageCredentials | Coroutine[Any, Any, AzureBlobStorageCredentials]` is not awaitable
- 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:94:28: error[invalid-assignment] Object of type `T@resolve_block_document_references | dict[str, Any]` 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/integrations/prefect-dbt/prefect_dbt/core/settings.py:99:28: error[invalid-assignment] Object of type `T@resolve_variables | dict[str, Any]` is not assignable to `dict[str, Any]`
- src/integrations/prefect-dbt/tests/cli/test_credentials.py:75:36: error[invalid-await] `None | Coroutine[Any, Any, None]` is not awaitable
+ src/integrations/prefect-dbt/tests/cli/test_credentials.py:75:36: error[invalid-await] `DbtCliProfile | Coroutine[Any, Any, DbtCliProfile]` is not awaitable
+ src/integrations/prefect-email/tests/test_credentials.py:91:12: warning[possibly-missing-attribute] Attribute `smtp_type` may be missing on object of type `EmailServerCredentials | Coroutine[Any, Any, EmailServerCredentials]`
+ src/integrations/prefect-email/tests/test_credentials.py:92:14: warning[possibly-missing-attribute] Attribute `get_server` may be missing on object of type `EmailServerCredentials | Coroutine[Any, Any, EmailServerCredentials]`
- src/integrations/prefect-email/tests/test_credentials.py:91:12: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `smtp_type`
+ src/integrations/prefect-email/tests/test_credentials.py:93:12: error[unresolved-attribute] Object of type `SMTP` has no attribute `port`
- src/integrations/prefect-email/tests/test_credentials.py:92:14: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `get_server`
- src/integrations/prefect-email/tests/test_credentials.py:108:12: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `smtp_type`
+ src/integrations/prefect-email/tests/test_credentials.py:108:12: warning[possibly-missing-attribute] Attribute `smtp_type` may be missing on object of type `EmailServerCredentials | Coroutine[Any, Any, EmailServerCredentials]`
+ src/integrations/prefect-email/tests/test_credentials.py:109:12: warning[possibly-missing-attribute] Attribute `verify` may be missing on object of type `EmailServerCredentials | Coroutine[Any, Any, EmailServerCredentials]`
+ src/integrations/prefect-email/tests/test_credentials.py:110:14: warning[possibly-missing-attribute] Attribute `get_server` may be missing on object of type `EmailServerCredentials | Coroutine[Any, Any, EmailServerCredentials]`
- src/integrations/prefect-email/tests/test_credentials.py:109:12: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `verify`
+ src/integrations/prefect-email/tests/test_credentials.py:111:12: error[unresolved-attribute] Object of type `SMTP` has no attribute `port`
- src/integrations/prefect-email/tests/test_credentials.py:110:14: error[unresolved-attribute] Object of type `None | Coroutine[Any, Any, None]` has no attribute `get_server`
- src/integrations/prefect-sqlalchemy/tests/test_database.py:447:18: error[invalid-context-manager] Object of type `None | Coroutine[Any, Any, None]` cannot be used with `with` because it does not implement `__enter__` and `__exit__`
+ src/integrations/prefect-sqlalchemy/tests/test_database.py:447:18: error[invalid-context-manager] Object of type `SqlAlchemyConnector | Coroutine[Any, Any, SqlAlchemyConnector]` cannot be used with `with` because the methods `__enter__` and `__exit__` are possibly missing
- src/integrations/prefect-sqlalchemy/tests/test_database.py:466:18: error[invalid-context-manager] Object of type `None | Coroutine[Any, Any, None]` cannot be used with `with` because it does not implement `__enter__` and `__exit__`
+ src/integrations/prefect-sqlalchemy/tests/test_database.py:466:18: error[invalid-context-manager] Object of type `SqlAlchemyConnector | Coroutine[Any, Any, SqlAlchemyConnector]` cannot be used with `with` because the methods `__enter__` and `__exit__` are possibly missing
- 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: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: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/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/deployment.py:292:49: error[unresolved-attribute] Object of type `None` has no attribute `model_dump`
- src/prefect/deployments/runner.py:795:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | ((...) -> Any)`
+ src/prefect/deployments/runner.py:795:70: warning[possibly-missing-attribute] Attribute `__name__` may be missing on object of type `Unknown | (((...) -> Any) & ((*args: object, **kwargs: object) -> object))`
- 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/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/pull.py:288:39: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `ReadableDeploymentStorage | WritableDeploymentStorage`, found `None`
+ src/prefect/deployments/steps/pull.py:288:39: error[invalid-argument-type] Argument to bound method `__init__` is incorrect: Expected `ReadableDeploymentStorage | WritableDeploymentStorage`, found `Block`
- src/prefect/flow_engine.py:696:32: error[unresolved-attribute] Object of type `None` has no attribute `client`
- src/prefect/flow_engine.py:812:32: error[invalid-await] `Unknown | R@FlowRunEngine | Coroutine[Any, Any, R@FlowRunEngine]` is not awaitable
- src/prefect/flow_engine.py:1278:32: error[unresolved-attribute] Object of type `None` has no attribute `client`
- src/prefect/flow_engine.py:1401:24: error[invalid-await] `Unknown | R@AsyncFlowRunEngine | Coroutine[Any, Any, R@AsyncFlowRunEngine]` is not awaitable
- src/prefect/flow_engine.py:1482:43: error[invalid-argument-type] Argument to function `next` is incorrect: Expected `SupportsNext[Unknown]`, found `Unknown | R@run_generator_flow_sync`
- src/prefect/flow_engine.py:1490:21: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_sync`
- src/prefect/flow_engine.py:1524:44: warning[possibly-missing-attribute] Attribute `__anext__` may be missing on object of type `Unknown | R@run_generator_flow_async`
- src/prefect/flow_engine.py:1531:25: warning[possibly-missing-attribute] Attribute `throw` may be missing on object of type `Unknown | R@run_generator_flow_async`
- src/prefect/flows.py:286:34: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
+ src/prefect/flows.py:286:34: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
- src/prefect/flows.py:404:68: error[unresolved-attribute] Object of type `(**P@Flow) -> R@Flow` has no attribute `__name__`
+ src/prefect/flows.py:404:68: error[unresolved-attribute] Object of type `((**P@Flow) -> R@Flow) & ((*args: object, **kwargs: object) -> object)` has no attribute `__name__`
+ src/prefect/flows.py:1750:53: warning[unused-ignore-comment] Unused blanket `type: ignore` directive
- src/prefect/task_engine.py:821:32: error[unresolved-attribute] Object of type `None` has no attribute `client`
- src/prefect/testing/utilities.py:280:17: error[invalid-argument-type] Argument to function `assert_blocks_equal` is incorrect: Expected `Block`, found `ReadableFileSystem | None`
- src/prefect/testing/utilities.py:291:17: error[invalid-argument-type] Argument to function `assert_blocks_equal` is incorrect: Expected `Block`, found `ReadableFileSystem | None`
- 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: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: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: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: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: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: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/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/workers/base.py:232:13: 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:232:13: 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:234:20: error[invalid-argument-type] Argument expression after ** must be a mapping type: Found `T@resolve_variables | str | int | ... omitted 4 union elements`
+ src/prefect/workers/base.py:234:20: error[invalid-argument-type] Argument expression after ** must be a mapping type: Found `T@resolve_variables`
- Found 5532 diagnostics
+ Found 5523 diagnostics

jax (https://github.com/google/jax)
+ jax/_src/tree_util.py:302:31: error[invalid-argument-type] Argument to bound method `register_node` is incorrect: Expected `(Hashable, Iterable[object], /) -> T@register_pytree_node`, found `(_AuxData@register_pytree_node, _Children@register_pytree_node, /) -> T@register_pytree_node`
+ jax/_src/tree_util.py:305:31: error[invalid-argument-type] Argument to bound method `register_node` is incorrect: Expected `(Hashable, Iterable[object], /) -> T@register_pytree_node`, found `(_AuxData@register_pytree_node, _Children@register_pytree_node, /) -> T@register_pytree_node`
+ jax/_src/tree_util.py:308:31: error[invalid-argument-type] Argument to bound method `register_node` is incorrect: Expected `(Hashable, Iterable[object], /) -> T@register_pytree_node`, found `(_AuxData@register_pytree_node, _Children@register_pytree_node, /) -> T@register_pytree_node`
- Found 2793 diagnostics
+ Found 2796 diagnostics

static-frame (https://github.com/static-frame/static-frame)
- 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[Bus[Any]] | TypeBlocks | Batch | ... omitted 6 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]]`

core (https://github.com/home-assistant/core)
+ 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 14470 diagnostics
+ Found 14471 diagnostics

No memory usage changes detected ✅

[eclbg]

I feel this is somewhat redundant with the change in bind_self in signatures.rs. In both places I'm detecting whether the method is a classmethod in different ways. Open to alternatives, of course.