[red-knot] Assignability for subclasses of Any and Unknown
#17557
Conversation
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
|
sharkdp
commented
Apr 22, 2025
sharkdp
commented
Apr 22, 2025
AlexWaygood
changed the title
AlexWaygood
approved these changes
Apr 22, 2025
There was a problem hiding this comment.
This LGTM, though I'd also include Unknown, and I think making some exceptions for @final classes does make sense.
It's unrelated to your PR, but while we're here: I find the comment at the top of this is_assignable_to method slightly confusing. I'm not sure what it's trying to say (or why); I'd be inclined to just delete it?
sharkdp
added a commit
that referenced
this pull request
Apr 23, 2025
## Summary We currently emit a diagnostic for code like the following: ```py from typing import Any # error: Invalid class base with type `GenericAlias` (all bases must be a class, `Any`, `Unknown` or `Todo`) class C(tuple[Any, ...]): ... ``` The changeset here silences this diagnostic by recognizing instances of `GenericAlias` in `ClassBase::try_from_type`, and inferring a `@Todo` type for them. This is a change in preparation for #17557, because `C` previously had `Unknown` in its MRO … ```py reveal_type(C.__mro__) # tuple[Literal[C], Unknown, Literal[object]] ``` … which would cause us to think that `C` is assignable to everything. The changeset also removes some false positive `invalid-base` diagnostics across the ecosystem. ## Test Plan Updated Markdown tests.
sharkdp
force-pushed
the
david/subtype-of-any-assignability
branch
from
79df46c to
d457975
Compare
sharkdp
changed the title
Any and Unknown
|
With the new changes, we also allow subclasses of # This is a union with Unknown, because `IOError` is a
# simple `IOError = OSError` type alias in typeshed
reveal_type(IOError) # Unknown | Literal[OSError]
class MyError(IOError): ...
reveal_type(MyError.__mro__) # tuple[Literal[MyError], Unknown, Literal[object]]
raise MyError() # no invalid-raise diagnostic anymorewe still raise "Invalid class base with type |
dcreager
added a commit
that referenced
this pull request
Apr 23, 2025
* main: (28 commits) [red-knot] Make `BoundMethodType` a salsa interned (#17581) [red-knot] Emit a diagnostic if a non-protocol is passed to `get_protocol_members` (#17551) [red-knot] Add more tests for protocol members (#17550) [red-knot] Assignability for subclasses of `Any` and `Unknown` (#17557) [red-knot] mypy_primer: add strawberry, print compilation errors to stderr (#17578) [red-knot] GenericAlias instances as a base class (#17575) Remove redundant `type_to_visitor_function` entries (#17564) Fixes how the checker visits `typing.cast`/`typing.NewType` arguments (#17538) [red-knot] Class literal `__new__` function callable subtyping (#17533) [red-knot] Surround intersections with `()` in potentially ambiguous contexts (#17568) [minor] Delete outdated TODO comment (#17565) [red-knot] add regression test for fixed cycle panic (#17535) [red-knot] fix unions of literals, again (#17534) red_knot_python_semantic: remove last vestige of old diagnostics! red_knot_python_semantic: migrate `types` to new diagnostics red_knot_python_semantic: migrate `types/diagnostic` to new diagnostics red_knot_python_semantic: migrate `types/call/bind` to new diagnostics red_knot_python_semantic: migrate `types/string_annotation` to new diagnostics red_knot_python_semantic: migrate `types/infer` to new diagnostic model red_knot_python_semantic: migrate INVALID_ASSIGNMENT for inference ...
dcreager
added a commit
that referenced
this pull request
Apr 23, 2025
…var-instance * dcreager/generic-constructor: (29 commits) We don't need this [red-knot] Make `BoundMethodType` a salsa interned (#17581) [red-knot] Emit a diagnostic if a non-protocol is passed to `get_protocol_members` (#17551) [red-knot] Add more tests for protocol members (#17550) [red-knot] Assignability for subclasses of `Any` and `Unknown` (#17557) [red-knot] mypy_primer: add strawberry, print compilation errors to stderr (#17578) [red-knot] GenericAlias instances as a base class (#17575) Remove redundant `type_to_visitor_function` entries (#17564) Fixes how the checker visits `typing.cast`/`typing.NewType` arguments (#17538) [red-knot] Class literal `__new__` function callable subtyping (#17533) [red-knot] Surround intersections with `()` in potentially ambiguous contexts (#17568) [minor] Delete outdated TODO comment (#17565) [red-knot] add regression test for fixed cycle panic (#17535) [red-knot] fix unions of literals, again (#17534) red_knot_python_semantic: remove last vestige of old diagnostics! red_knot_python_semantic: migrate `types` to new diagnostics red_knot_python_semantic: migrate `types/diagnostic` to new diagnostics red_knot_python_semantic: migrate `types/call/bind` to new diagnostics red_knot_python_semantic: migrate `types/string_annotation` to new diagnostics red_knot_python_semantic: migrate `types/infer` to new diagnostic model ...
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
Summary
Allow (instances of) subclasses of
AnyandUnknownto be assignable to (instances of) other classes, unless they are final. This allows us to get rid of ~1000 false positives, mostly when mock-objects likeunittest.mock.MagicMockare assigned to various targets.Test Plan
Adapted and new Markdown tests.