fix another unsafe_op_in_unsafe_fn trigger (#4753)

Author: Icxolu

pyo3-macros-backend/src/params.rs

@@ -265,9 +265,10 @@ pub(crate) fn impl_regular_arg_param(
                 )?
             }
         } else {
+            let unwrap = quote! {unsafe { #pyo3_path::impl_::extract_argument::unwrap_required_argument(#arg_value) }};
             quote_arg_span! {
                 #pyo3_path::impl_::extract_argument::from_py_with(
-                    #pyo3_path::impl_::extract_argument::unwrap_required_argument(#arg_value),
+                    #unwrap,
                     #name_str,
                     #from_py_with as fn(_) -> _,
                 )?

tests/ui/forbid_unsafe.rs

@@ -28,4 +28,16 @@ mod gh_4394 {
     pub struct Version;
 }
 
+mod from_py_with {
+    use pyo3::prelude::*;
+    use pyo3::types::PyBytes;
+
+    fn bytes_from_py(bytes: &Bound<'_, PyAny>) -> PyResult<Vec<u8>> {
+        Ok(bytes.downcast::<PyBytes>()?.as_bytes().to_vec())
+    }
+
+    #[pyfunction]
+    fn f(#[pyo3(from_py_with = "bytes_from_py")] _bytes: Vec<u8>) {}
+}
+
 fn main() {}