justin 39b41838f3 [ty] synthesize __setattr__ for frozen dataclasses (#19307) ...

## Summary

Synthesize a `__setattr__` method with a return type of `Never` for
frozen dataclasses.

https://docs.python.org/3/library/dataclasses.html#frozen-instances

https://docs.python.org/3/library/dataclasses.html#dataclasses.FrozenInstanceError

### Related
https://github.com/astral-sh/ty/issues/111
https://github.com/astral-sh/ruff/pull/17974#discussion_r2108527106
https://github.com/astral-sh/ruff/pull/18347#discussion_r2128174665

## Test Plan

New Markdown tests

---------

Co-authored-by: David Peter <mail@david-peter.de>

2025-07-18 11:35:05 +02:00

..

dataclass_transform.md

[ty] Restructure/move dataclass tests (#19117)

2025-07-03 10:36:14 +00:00

dataclasses.md

[ty] synthesize __setattr__ for frozen dataclasses (#19307)

2025-07-18 11:35:05 +02:00

fields.md

[ty] Enum literal types (#19328)

2025-07-15 21:31:53 +02:00