## Summary
The `Visitor` and `preorder::Visitor` traits provide some convenience
functions, `visit_annotation` and `visit_format_spec`, for handling
annotation and format spec expressions respectively. Both of these
functions accept an `&Expr` and have a default implementation which
delegates to `walk_expr`. The problem with this approach is that any
custom handling done in `visit_expr` will be skipped for annotations and
format specs. Instead, to capture any custom logic implemented in
`visit_expr`, both of these function's default implementations should
delegate to `visit_expr` instead of `walk_expr`.
## Example
Consider the below `Visitor` implementation:
```rust
impl<'a> Visitor<'a> for Example<'a> {
fn visit_expr(&mut self, expr: &'a Expr) {
match expr {
Expr::Name(ExprName { id, .. }) => println!("Visiting {:?}", id),
_ => walk_expr(self, expr),
}
}
}
```
Run on the following Python snippet:
```python
a: b
```
I would expect such a visitor to print the following:
```
Visiting b
Visiting a
```
But it instead prints the following:
```
Visiting a
```
Our custom `visit_expr` handler is not invoked for the annotation.
## Test Plan
Tests added in #5271 caught this behavior.
## Summary
This PR upgrade RustPython to pull in the changes to `Arguments` (zip
defaults with their identifiers) and all the renames to `CmpOp` and
friends.
## Summary
This PR runs `rustfmt` with a few nightly options as a one-time fix to
catch some malformatted comments. I ended up just running with:
```toml
condense_wildcard_suffixes = true
edition = "2021"
max_width = 100
normalize_comments = true
normalize_doc_attributes = true
reorder_impl_items = true
unstable_features = true
use_field_init_shorthand = true
```
Since these all seem like reasonable things to fix, so may as well while
I'm here.
Charlie Marsh
James Berry
Micha Reiser