## Summary
I only noticed this in the ecosystem report of
https://github.com/astral-sh/ruff/pull/22213 after merging it. The
change to displaying `Top[]` wrapper around the entire signature instead
of just the parameters had the side effect of not showing it at all when
displaying a top ParamSpec specialization. This PR fixes that.
Marking internal since this is a fixup of a not-released PR.
## Test Plan
Added mdtest that fails without this PR.
## Summary
A couple things I noticed when taking another look at the callable type
materializations.
1) Previously we wrongly ignored the return type when
bottom-materializing a callable with gradual signature, and always
changed it to `Never`.
2) We weren't correctly handling overloads that included a gradual
signature. Rather than separately materializing each overload, we would
just mark the entire callable as "top" or replace the entire callable
with the bottom signature.
Really, "top parameters" is something that belongs on the `Parameters`,
not on the entire `CallableType`. Conveniently, we already have
`ParametersKind` where we can track this, right next to where we already
track `ParametersKind::Gradual`. This saves a bit of memory, fixes the
two bugs above, and simplifies the implementation considerably (net
removal of 100+ LOC, a bunch of places that shouldn't need to care about
topness of a callable no longer need to.)
One user-visible change from this is that I now display the "top
callable" as `(Top[...]) -> object` instead of `Top[(...) -> object]`. I
think this is a (minor) improvement, because it wraps exactly the part
in `Top` that needs to be, rather than misleadingly wrapping the entire
callable type, including the return type (which has already been
separately materialized). I think the prior display would be
particularly confusing if the return type also has its own `Top` in it:
previously we could have e.g. `Top[(...) -> Top[list[Unknown]]]`, which
I think is less clear than the new `(Top[...]) -> Top[list[Unknown]]`.
## Test Plan
Added mdtests that failed before this PR and pass after it.
### Ecosystem
The changed diagnostics are all either the change to `Top` display, or
else known non-deterministic output. The added diagnostics are all true
positives:
The added diagnostic at
aa35ca1965/torchvision/transforms/v2/_utils.py (L149)
is a true positive that wasn't caught by the previous version. `str` is
not assignable to `Callable[[Any], Any]` (strings are not callable), nor
is the top callable (top callable includes callables that do not take a
single required positional argument.)
The added diagnostic at
081535ad9b/starlette/routing.py (L67)
is also a (pedantic) true positive. It's the same case as #1567 -- the
code assumes that it is impossible for a subclass of `Response` to
implement `__await__` (yielding something other than a `Response`).
The pytest added diagnostics are also both similar true positives: they
make the assumption that an object cannot simultaneously be a `Sequence`
and callable, or an `Iterable` and callable.
## Summary
Resolve https://github.com/astral-sh/ty/issues/2226
We need to add a special case in `apply_type_mapping` instead of
directly in `promote_literals_impl` because we do not reach this with
non generic non tuple nominal instances. We still ensure we apply the
normal mapping if we do not see `float` or `complex` instances.
## Test Plan
Update existing mdtest and add a new case to `literal_promotion.md`
