[ty] Add diagnostics for __init_subclass__ argument mismatch#22185
Merged
AlexWaygood merged 2 commits intoastral-sh:mainfrom Jan 13, 2026
Merged
[ty] Add diagnostics for __init_subclass__ argument mismatch#22185AlexWaygood merged 2 commits intoastral-sh:mainfrom
__init_subclass__ argument mismatch#22185AlexWaygood merged 2 commits intoastral-sh:mainfrom
Conversation
RasmusNygren
requested review from
AlexWaygood,
carljm,
dcreager and
sharkdp
as code owners
Diagnostic diff on typing conformance testsNo changes detected when running ty on typing conformance tests ✅ |
|
RasmusNygren
commented
Dec 24, 2025
| } | ||
|
|
||
| // (6) If the class is generic, verify that its generic context does not violate any of | ||
| // (6) Check that the class arguments matches the arguments of the |
Contributor
Author
There was a problem hiding this comment.
It's not very satisfying how big the check_class_definitions function is becoming, but refactors aside I think this is probably a reasonable place to add these checks? This is not really a part of the code base I've been modifying before though so I could be wrong :)
Member
|
Thank you for your work on this feature. Almost the entire team was out last week and is out this week. It may take a few days before someone finds time to review your PR. Happy holidays. |
Contributor
Author
Absolutely no worries, we all need a well-deserved break :) Happy holidays to all of you! |
RasmusNygren
force-pushed
the
type-validate-init-subclass
branch
from
aa2acc3 to
98830bd
Compare
Add diagnostics when class definitions pass invalid arguments for a base class `__init_subclass__`.
RasmusNygren
force-pushed
the
type-validate-init-subclass
branch
from
98830bd to
47f9096
Compare
AlexWaygood
approved these changes
Jan 13, 2026
Member
AlexWaygood
left a comment
AlexWaygood
left a comment
There was a problem hiding this comment.
Thank you!
I wish we could make the diagnostics here a bit friendlier. Some users may not be aware of how the semantics of __init_subclass__ work, and the diagnostic doesn't try to explain it much at the moment:
But propagating context into (or out of) binding.report_diagnostics() in order to add subdiagnostics looks really complicated
Member
I opened astral-sh/ty#2482 to track this |
Member
|
(cc. @charliermarsh -- we discussed this PR a bit in #22291. It's now landed!) |
AlexWaygood
pushed a commit
that referenced
this pull request
Jan 14, 2026
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
3 participants
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
Add diagnostics when class definitions pass invalid arguments for a base class
__init_subclass__.Fixes astral-sh/ty#1541
Test Plan
New tests