pyfunction: fix clippy lint on **kwargs argument

Author: davidhewitt

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fix visibility of `PyDictItems`, `PyDictKeys`, and `PyDictValues` types added in PyO3 0.17.0.
 - Fix compile failure when using `#[pyo3(from_py_with = "...")]` attribute on an argument of type `Option<T>`. [#2592](https://github.com/PyO3/pyo3/pull/2592)
+- Fix clippy `redundant-closure` lint on `**kwargs` arguments for `#[pyfunction]` and `#[pymethods]`. [#2595](https://github.com/PyO3/pyo3/pull/2595)
 
 ## [0.17.0] - 2022-08-23
 

pyo3-macros-backend/src/params.rs

@@ -220,7 +220,7 @@ fn impl_arg_param(
         );
         return Ok(quote_arg_span! {
             _pyo3::impl_::extract_argument::extract_optional_argument(
-                _kwargs.map(|kwargs| kwargs.as_ref()),
+                _kwargs.map(::std::convert::AsRef::as_ref),
                 &mut { _pyo3::impl_::extract_argument::FunctionArgumentHolder::INIT },
                 #name_str
             )?