## Summary
We're actually quite good at computing this but the main issue is just
that we compute it at the type-level and so wrap it in `Literal[...]`.
So just special-case the rendering of these to omit `Literal[...]` and
fallback to `...` in cases where the thing we'll show is probably
useless (i.e. `x: str = str`).
Fixes https://github.com/astral-sh/ty/issues/1882
## Summary
Not a high-priority task... but it _is_ a weekend :P
This PR improves our diagnostics for invalid exceptions. Specifically:
- We now give a special-cased ``help: Did you mean
`NotImplementedError`` subdiagnostic for `except NotImplemented`, `raise
NotImplemented` and `raise <EXCEPTION> from NotImplemented`
- If the user catches a tuple of exceptions (`except (foo, bar, baz):`)
and multiple elements in the tuple are invalid, we now collect these
into a single diagnostic rather than emitting a separate diagnostic for
each tuple element
- The explanation of why the `except`/`raise` was invalid ("must be a
`BaseException` instance or `BaseException` subclass", etc.) is
relegated to a subdiagnostic. This makes the top-level diagnostic
summary much more concise.
## Test Plan
Lots of snapshots. And here's some screenshots:
<details>
<summary>Screenshots</summary>
<img width="1770" height="1520" alt="image"
src="https://github.com/user-attachments/assets/7f27fd61-c74d-4ddf-ad97-ea4fd24d06fd"
/>
<img width="1916" height="1392" alt="image"
src="https://github.com/user-attachments/assets/83e5027c-8798-48a6-a0ec-1babfc134000"
/>
<img width="1696" height="588" alt="image"
src="https://github.com/user-attachments/assets/1bc16048-6eb4-4dfa-9ace-dd271074530f"
/>
</details>
## Summary
This PR closes https://github.com/astral-sh/ty/issues/238.
Since `DefinitionState::Deleted` was introduced in #18041, support for
the `del` statement (and deletion of except handler names) is
straightforward.
However, it is difficult to determine whether references to attributes
or subscripts are unresolved after they are deleted. This PR only
invalidates narrowing by assignment if the attribute or subscript is
deleted.
## Test Plan
`mdtest/del.md` is added.
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
Aria Desires
Alex Waygood
Douglas Creager
Shunsuke Shibayama
Adam Aaronson
Felix Scherz
Charlie Marsh
Micha Reiser