## Summary
Adds a simple progress bar for the `ty check` CLI command. The style is
taken from uv, and like uv the bar is always shown - for smaller
projects it is fast enough that it isn't noticeable. We could
alternatively hide it completely based on some heuristic for the number
of files, or only show it after some amount of time.
I also disabled it when `--watch` is passed, cancelling inflight checks
was leading to zombie progress bars. I think we can fix this by using
[`MultiProgress`](https://docs.rs/indicatif/latest/indicatif/struct.MultiProgress.html)
and managing all the bars globally, but I left that out for now.
Resolves https://github.com/astral-sh/ty/issues/98.
## Summary
This PR is a first step toward integration of the new `Diagnostic` type
into ruff. There are two main changes:
- A new `UnifiedFile` enum wrapping `File` for red-knot and a
`SourceFile` for ruff
- ruff's `Message::SyntaxError` variant is now a `Diagnostic` instead of
a `SyntaxErrorMessage`
The second of these changes was mostly just a proof of concept for the
first, and it went pretty smoothly. Converting `DiagnosticMessage`s will
be most of the work in replacing `Message` entirely.
## Test Plan
Existing tests, which show no changes.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Co-authored-by: Micha Reiser <micha@reiser.io>
## Summary
When entering an `infer_expression_types` cycle from
`TypeInferenceBuilder::infer_standalone_expression`, we might get back a
`TypeInference::cycle_fallback(…)` that doesn't actually contain any new
types, but instead it contains a `cycle_fallback_type` which is set to
`Some(Type::Never)`. When calling `self.extend(…)`, we therefore don't
really pull in a type for the expression we're interested in. This
caused us to panic if we tried to call `self.expression_type(…)` after
`self.extend(…)`.
The proposed fix here is to retrieve that type from the nested
`TypeInferenceBuilder` directly, which will correctly fall back to
`cycle_fallback_type`.
## Details
I minimized the second example from #17792 a bit further and used this
example for debugging:
```py
from __future__ import annotations
class C: ...
def f(arg: C):
pass
x, _ = f(1)
assert x
```
This is self-referential because when we check the assignment statement
`x, _ = f(1)`, we need to look up the signature of `f`. Since evaluation
of annotations is deferred, we look up the public type of `C` for the
`arg` parameter. The public use of `C` is visibility-constraint by "`x`"
via the `assert` statement. While evaluating this constraint, we need to
look up the type of `x`, which in turn leads us back to the `x, _ =
f(1)` definition.
The reason why this only showed up in the relatively peculiar case with
unpack assignments is the code here:
78b4c3ccf1/crates/ty_python_semantic/src/types/infer.rs (L2709-L2718)
For a non-unpack assignment like `x = f(1)`, we would not try to infer
the right-hand side eagerly. Instead, we would enter a
`infer_definition_types` cycle that handles the situation correctly. For
unpack assignments, however, we try to infer the type of `value`
(`f(1)`) and therefore enter the cycle via `standalone_expression_type
=> infer_expression_type`.
closes#17792
## Test Plan
* New regression test
* Made sure that we can now run successfully on scipy => see #17850
