## Summary
This is a follow-up to #15565, tracked in #15642, to reuse the string
replacement logic from the other PEP 695 rules instead of the
`Generator`, which has the benefit of preserving more comments. However,
comments in some places are still dropped, so I added a check for this
and update the fix safety accordingly. I also added a `## Fix safety`
section to the docs to reflect this and the existing `isinstance`
caveat.
## Test Plan
Existing UP040 tests, plus some new cases.
## Summary
This PR extends our [PEP 695](https://peps.python.org/pep-0695) handling
from the type aliases handled by `UP040` to generic function and class
parameters, as suggested in the latter two examples from #4617:
```python
# Input
T = TypeVar("T", bound=float)
class A(Generic[T]):
...
def f(t: T):
...
# Output
class A[T: float]:
...
def f[T: float](t: T):
...
```
I first implemented this as part of `UP040`, but based on a brief
discussion during a very helpful pairing session with @AlexWaygood, I
opted to split them into rules separate from `UP040` and then also
separate from each other. From a quick look, and based on [this
issue](https://github.com/asottile/pyupgrade/issues/836), I'm pretty
sure neither of these rules is currently in pyupgrade, so I just took
the next available codes, `UP046` and `UP047`.
The last main TODO, noted in the rule file and in the fixture, is to
handle generic method parameters not included in the class itself, `S`
in this case:
```python
T = TypeVar("T")
S = TypeVar("S")
class Foo(Generic[T]):
def bar(self, x: T, y: S) -> S: ...
```
but Alex mentioned that that might be okay to leave for a follow-up PR.
I also left a TODO about handling multiple subclasses instead of bailing
out when more than one is present. I'm not sure how common that would
be, but I can still handle it here, or follow up on that too.
I think this is unrelated to the PR, but when I ran `cargo dev
generate-all`, it removed the rule code `PLW0101` from
`ruff.schema.json`. It seemed unrelated, so I left that out, but I
wanted to mention it just in case.
## Test Plan
New test fixture, `cargo nextest run`
Closes#4617, closes#12542
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
## Summary
If a generic appears multiple times on the right-hand side, we should
only include it once on the left-hand side when rewriting.
Closes https://github.com/astral-sh/ruff/issues/9904.
