## Summary
This PR adds support for unpacking tuple expression in an assignment
statement where the target expression can be a tuple or a list (the
allowed sequence targets).
The implementation introduces a new `infer_assignment_target` which can
then be used for other targets like the ones in for loops as well. This
delegates it to the `infer_definition`. The final implementation uses a
recursive function that visits the target expression in source order and
compares the variable node that corresponds to the definition. At the
same time, it keeps track of where it is on the assignment value type.
The logic also accounts for the number of elements on both sides such
that it matches even if there's a gap in between. For example, if
there's a starred expression like `(a, *b, c) = (1, 2, 3)`, then the
type of `a` will be `Literal[1]` and the type of `b` will be
`Literal[2]`.
There are a couple of follow-ups that can be done:
* Use this logic for other target positions like `for` loop
* Add diagnostics for mis-match length between LHS and RHS
## Test Plan
Add various test cases using the new markdown test framework.
Validate that existing test cases pass.
---------
Co-authored-by: Carl Meyer <carl@astral.sh>
Test coverage for #13131 wasn't as good as I thought it was, because
although we infer a lot of types in stubs in typeshed, we don't check
typeshed, and therefore we don't do scope-level inference and pull all
types for a scope. So we didn't really have good test coverage for
scope-level inference in a stub. And because of this, I got the code for
supporting that wrong, meaning that if we did scope-level inference with
deferred types, we'd end up never populating the deferred types in the
scope's `TypeInference`, which causes panics like #13160.
Here I both add test coverage by running the corpus tests both as `.py`
and as `.pyi` (which reveals the panic), and I fix the code to support
deferred types in scope inference.
This also revealed a problem with deferred types in generic functions,
which effectively span two scopes. That problem will require a bit more
thought, and I don't want to block this PR on it, so for now I just
don't defer annotations on generic functions.
Fixes#13160.
## Summary
This PR separates the current `red_knot` crate into two crates:
1. `red_knot` - This will be similar to the `ruff` crate, it'll act as
the CLI crate
2. `red_knot_workspace` - This includes everything except for the CLI
functionality from the existing `red_knot` crate
Note that the code related to the file watcher is in
`red_knot_workspace` for now but might be required to extract it out in
the future.
The main motivation for this change is so that we can have a `red_knot
server` command. This makes it easier to test the server out without
making any changes in the VS Code extension. All we need is to specify
the `red_knot` executable path in `ruff.path` extension setting.
## Test Plan
- `cargo build`
- `cargo clippy --workspace --all-targets --all-features`
- `cargo shear --fix`
