Removed PyClone trait, moved it methods to Element, and updated i…

…mplementations/usages.

The updates including renaming the `py_clone` method to `clone_ref` to match that of `Py::clone_ref`, and replacing the `impl_py_clone!` macro with `clone_methods_impl!`.

src/array.rs

@@ -1473,7 +1473,7 @@ unsafe fn clone_elements<T: Element>(py: Python<'_>, elems: &[T], data_ptr: &mut
         *data_ptr = data_ptr.add(elems.len());
     } else {
         for elem in elems {
-            data_ptr.write(elem.py_clone(py));
+            data_ptr.write(elem.clone_ref(py));
             *data_ptr = data_ptr.add(1);
         }
     }
@@ -2205,7 +2205,7 @@ impl<'py, T, D> PyArrayMethods<'py, T, D> for Bound<'py, PyArray<T, D>> {
         Idx: NpyIndex<Dim = D>,
     {
         let element = unsafe { self.get(index) };
-        element.map(|elem| elem.py_clone(self.py()))
+        element.map(|elem| elem.clone_ref(self.py()))
     }
 
     fn to_dyn(&self) -> &Bound<'py, PyArray<T, IxDyn>> {

src/convert.rs

@@ -203,7 +203,7 @@ where
                     let array = PyArray::<A, _>::new_bound(py, dim, false);
                     let mut data_ptr = array.data();
                     for item in self.iter() {
-                        data_ptr.write(item.py_clone(py));
+                        data_ptr.write(item.clone_ref(py));
                         data_ptr = data_ptr.add(1);
                     }
                     array
@@ -236,7 +236,7 @@ where
                 ptr::copy_nonoverlapping(self.data.ptr(), data_ptr, self.len());
             } else {
                 for item in self.iter() {
-                    data_ptr.write(item.py_clone(py));
+                    data_ptr.write(item.clone_ref(py));
                     data_ptr = data_ptr.add(1);
                 }
             }

src/datetime.rs

@@ -66,7 +66,7 @@ use std::marker::PhantomData;
 use pyo3::{sync::GILProtected, Bound, Py, Python};
 use rustc_hash::FxHashMap;
 
-use crate::dtype::{Element, PyArrayDescr, PyArrayDescrMethods, impl_py_clone};
+use crate::dtype::{Element, PyArrayDescr, PyArrayDescrMethods, clone_methods_impl};
 use crate::npyffi::{
     PyArray_DatetimeDTypeMetaData, PyDataType_C_METADATA, NPY_DATETIMEUNIT, NPY_TYPES,
 };
@@ -155,8 +155,6 @@ impl<U: Unit> From<Datetime<U>> for i64 {
     }
 }
 
-impl_py_clone!(Datetime<U>; [U: Unit]);
-
 unsafe impl<U: Unit> Element for Datetime<U> {
     const IS_COPY: bool = true;
 
@@ -165,6 +163,8 @@ unsafe impl<U: Unit> Element for Datetime<U> {
 
         DTYPES.from_unit(py, U::UNIT)
     }
+
+    clone_methods_impl!(Self);
 }
 
 impl<U: Unit> fmt::Debug for Datetime<U> {
@@ -192,8 +192,6 @@ impl<U: Unit> From<Timedelta<U>> for i64 {
     }
 }
 
-impl_py_clone!(Timedelta<U>; [U: Unit]);
-
 unsafe impl<U: Unit> Element for Timedelta<U> {
     const IS_COPY: bool = true;
 
@@ -202,6 +200,8 @@ unsafe impl<U: Unit> Element for Timedelta<U> {
 
         DTYPES.from_unit(py, U::UNIT)
     }
+
+    clone_methods_impl!(Self);
 }
 
 impl<U: Unit> fmt::Debug for Timedelta<U> {

src/dtype.rs

@@ -10,10 +10,10 @@ use pyo3::{
     ffi::{self, PyTuple_Size},
     pyobject_native_type_extract, pyobject_native_type_named,
     types::{PyAnyMethods, PyDict, PyDictMethods, PyTuple, PyType},
-    Borrowed, Bound, PyAny, PyObject, PyResult, PyTypeInfo, Python, ToPyObject,
+    Borrowed, Bound, Py, PyAny, PyObject, PyResult, PyTypeInfo, Python, ToPyObject,
 };
 #[cfg(feature = "half")]
-use pyo3::{sync::GILOnceCell, Py};
+use pyo3::{sync::GILOnceCell};
 #[cfg(feature = "gil-refs")]
 use pyo3::{AsPyPointer, PyNativeType};
 
@@ -644,56 +644,6 @@ impl<'py> PyArrayDescrMethods<'py> for Bound<'py, PyArrayDescr> {
 
 impl Sealed for Bound<'_, PyArrayDescr> {}
 
-/// Weaker form of `Clone` for types that can be cloned while the GIL is held.
-///
-/// Any type that implements `Clone` can trivially implement `PyClone` by forwarding
-/// to the `Clone::clone` method. However, some types (notably `PyObject`) can only
-/// be safely cloned while the GIL is held, and therefore cannot implement `Clone`.
-/// This trait provides a mechanism for performing a clone while the GIL is held, as
-/// represented by the [`Python`] token provided as an argument to the [`py_clone`]
-/// method. All API's in the `numpy` crate require the GIL to be held, so this weaker
-/// alternative to `Clone` is a sufficient prerequisite for implementing the
-/// [`Element`] trait.
-///
-/// # Implementing `PyClone`
-/// Implementing this trait is trivial for most types, and simply requires defining
-/// the `py_clone` method. The `vec_from_slice` and `array_from_view` methods have
-/// default implementations that simply map the `py_clone` method to each item in
-/// the collection, but types may want to override these implementations if there
-/// is a more efficient way to perform the conversion. In particular, `Clone` types
-/// may instead defer to the `ToOwned::to_owned` and `ArrayBase::to_owned` methods
-/// for increased performance.
-///
-/// [`py_clone`]: Self::py_clone
-pub trait PyClone: Sized {
-    /// Create a clone of the value while the GIL is guaranteed to be held.
-    fn py_clone(&self, py: Python<'_>) -> Self;
-
-    /// Create an owned copy of the slice while the GIL is guaranteed to be held.
-    ///
-    /// Some types may provide implementations of this method that are more efficient
-    /// than simply mapping the `py_clone` method to each element in the slice.
-    #[inline]
-    fn vec_from_slice(py: Python<'_>, slc: &[Self]) -> Vec<Self> {
-        slc.iter().map(|elem| elem.py_clone(py)).collect()
-    }
-
-    /// Create an owned copy of the array while the GIL is guaranteed to be held.
-    ///
-    /// Some types may provide implementations of this method that are more efficient
-    /// than simply mapping the `py_clone` method to each element in the view.
-    #[inline]
-    fn array_from_view<D>(
-        py: Python<'_>,
-        view: ::ndarray::ArrayView<'_, Self, D>,
-    ) -> ::ndarray::Array<Self, D>
-    where
-        D: ::ndarray::Dimension,
-    {
-        view.map(|elem| elem.py_clone(py))
-    }
-}
-
 /// Represents that a type can be an element of `PyArray`.
 ///
 /// Currently, only integer/float/complex/object types are supported. The [NumPy documentation][enumerated-types]
@@ -731,7 +681,7 @@ pub trait PyClone: Sized {
 ///
 /// [enumerated-types]: https://numpy.org/doc/stable/reference/c-api/dtype.html#enumerated-types
 /// [data-models]: https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models
-pub unsafe trait Element: PyClone + Send {
+pub unsafe trait Element: Sized + Send {
     /// Flag that indicates whether this type is trivially copyable.
     ///
     /// It should be set to true for all trivially copyable types (like scalar types
@@ -749,6 +699,33 @@ pub unsafe trait Element: PyClone + Send {
 
     /// Returns the associated type descriptor ("dtype") for the given element type.
     fn get_dtype_bound(py: Python<'_>) -> Bound<'_, PyArrayDescr>;
+
+    /// Create a clone of the value while the GIL is guaranteed to be held.
+    fn clone_ref(&self, py: Python<'_>) -> Self;
+
+    /// Create an owned copy of the slice while the GIL is guaranteed to be held.
+    ///
+    /// Some types may provide implementations of this method that are more efficient
+    /// than simply mapping the `py_clone` method to each element in the slice.
+    #[inline]
+    fn vec_from_slice(py: Python<'_>, slc: &[Self]) -> Vec<Self> {
+        slc.iter().map(|elem| elem.clone_ref(py)).collect()
+    }
+
+    /// Create an owned copy of the array while the GIL is guaranteed to be held.
+    ///
+    /// Some types may provide implementations of this method that are more efficient
+    /// than simply mapping the `py_clone` method to each element in the view.
+    #[inline]
+    fn array_from_view<D>(
+        py: Python<'_>,
+        view: ::ndarray::ArrayView<'_, Self, D>,
+    ) -> ::ndarray::Array<Self, D>
+    where
+        D: ::ndarray::Dimension,
+    {
+        view.map(|elem| elem.clone_ref(py))
+    }
 }
 
 fn npy_int_type_lookup<T, T0, T1, T2>(npy_types: [NPY_TYPES; 3]) -> NPY_TYPES {
@@ -796,34 +773,33 @@ fn npy_int_type<T: Bounded + Zero + Sized + PartialEq>() -> NPY_TYPES {
     }
 }
 
-// Implements `PyClone` for a type that implements `Clone`
-macro_rules! impl_py_clone {
-    ($ty:ty $(; [$param:ident $(: $bound:ident)?])?) => {
-        impl <$($param$(: $bound)*)?> $crate::dtype::PyClone for $ty {
-            #[inline]
-            fn py_clone(&self, _py: ::pyo3::Python<'_>) -> Self {
-                self.clone()
-            }
+// Invoke within the `Element` impl for a `Clone` type to provide an efficient
+// implementation of the cloning methods
+macro_rules! clone_methods_impl {
+    ($Self:ty) => {
+        #[inline]
+        fn clone_ref(&self, _py: ::pyo3::Python<'_>) -> $Self {
+            ::std::clone::Clone::clone(self)
+        }
 
-            #[inline]
-            fn vec_from_slice(_py: ::pyo3::Python<'_>, slc: &[Self]) -> Vec<Self> {
-                slc.to_owned()
-            }
+        #[inline]
+        fn vec_from_slice(_py: ::pyo3::Python<'_>, slc: &[$Self]) -> Vec<$Self> {
+            ::std::borrow::ToOwned::to_owned(slc)
+        }
 
-            #[inline]
-            fn array_from_view<D>(
-                _py: ::pyo3::Python<'_>,
-                view: ::ndarray::ArrayView<'_, Self, D>
-            ) -> ::ndarray::Array<Self, D>
-            where
-                D: ::ndarray::Dimension
-            {
-                view.to_owned()
-            }
+        #[inline]
+        fn array_from_view<D>(
+            _py: ::pyo3::Python<'_>,
+            view: ::ndarray::ArrayView<'_, $Self, D>
+        ) -> ::ndarray::Array<$Self, D>
+        where
+            D: ::ndarray::Dimension
+        {
+            ::ndarray::ArrayView::to_owned(&view)
         }
     }
 }
-pub(crate) use impl_py_clone;
+pub(crate) use clone_methods_impl;
 
 macro_rules! impl_element_scalar {
     (@impl: $ty:ty, $npy_type:expr $(,#[$meta:meta])*) => {
@@ -834,8 +810,9 @@ macro_rules! impl_element_scalar {
             fn get_dtype_bound(py: Python<'_>) -> Bound<'_, PyArrayDescr> {
                 PyArrayDescr::from_npy_type(py, $npy_type)
             }
+
+            clone_methods_impl!($ty);
         }
-        impl_py_clone!($ty);
     };
     ($ty:ty => $npy_type:ident $(,#[$meta:meta])*) => {
         impl_element_scalar!(@impl: $ty, NPY_TYPES::$npy_type $(,#[$meta])*);
@@ -870,10 +847,9 @@ unsafe impl Element for bf16 {
             .clone_ref(py)
             .into_bound(py)
     }
-}
 
-#[cfg(feature = "half")]
-impl_py_clone!(bf16);
+    clone_methods_impl!(Self);
+}
 
 impl_element_scalar!(Complex32 => NPY_CFLOAT,
     #[doc = "Complex type with `f32` components which maps to `numpy.csingle` (`numpy.complex64`)."]);
@@ -883,19 +859,17 @@ impl_element_scalar!(Complex64 => NPY_CDOUBLE,
 #[cfg(any(target_pointer_width = "32", target_pointer_width = "64"))]
 impl_element_scalar!(usize, isize);
 
-impl PyClone for PyObject {
-    #[inline]
-    fn py_clone(&self, py: Python<'_>) -> Self {
-        self.clone_ref(py)
-    }
-}
-
 unsafe impl Element for PyObject {
     const IS_COPY: bool = false;
 
     fn get_dtype_bound(py: Python<'_>) -> Bound<'_, PyArrayDescr> {
         PyArrayDescr::object_bound(py)
     }
+
+    #[inline]
+    fn clone_ref(&self, py: Python<'_>) -> Self {
+        Py::clone_ref(self, py)
+    }
 }
 
 #[cfg(test)]

src/lib.rs

@@ -114,7 +114,7 @@ pub use crate::convert::{IntoPyArray, NpyIndex, ToNpyDims, ToPyArray};
 #[cfg(feature = "gil-refs")]
 pub use crate::dtype::dtype;
 pub use crate::dtype::{
-    dtype_bound, Complex32, Complex64, Element, PyArrayDescr, PyArrayDescrMethods, PyClone,
+    dtype_bound, Complex32, Complex64, Element, PyArrayDescr, PyArrayDescrMethods,
 };
 pub use crate::error::{BorrowError, FromVecError, NotContiguousError};
 pub use crate::npyffi::{PY_ARRAY_API, PY_UFUNC_API};

src/strings.rs

@@ -17,7 +17,7 @@ use pyo3::{
 };
 use rustc_hash::FxHashMap;
 
-use crate::dtype::{Element, PyArrayDescr, PyArrayDescrMethods, PyClone};
+use crate::dtype::{clone_methods_impl, Element, PyArrayDescr, PyArrayDescrMethods};
 use crate::npyffi::PyDataType_SET_ELSIZE;
 use crate::npyffi::NPY_TYPES;
 
@@ -82,29 +82,8 @@ unsafe impl<const N: usize> Element for PyFixedString<N> {
 
         unsafe { DTYPES.from_size(py, NPY_TYPES::NPY_STRING, b'|' as _, size_of::<Self>()) }
     }
-}
-
-impl<const N: usize> PyClone for PyFixedString<N> {
-    #[inline]
-    fn py_clone(&self, _py: Python<'_>) -> Self {
-        *self
-    }
 
-    #[inline]
-    fn vec_from_slice(_py: Python<'_>, slc: &[Self]) -> Vec<Self> {
-        slc.to_owned()
-    }
-
-    #[inline]
-    fn array_from_view<D>(
-        _py: Python<'_>,
-        view: ::ndarray::ArrayView<'_, Self, D>,
-    ) -> ::ndarray::Array<Self, D>
-    where
-        D: ::ndarray::Dimension,
-    {
-        view.to_owned()
-    }
+    clone_methods_impl!(Self);
 }
 
 /// A newtype wrapper around [`[PyUCS4; N]`][Py_UCS4] to handle [`str_` scalars][numpy-str] while satisfying coherence.
@@ -168,29 +147,6 @@ impl<const N: usize> From<[Py_UCS4; N]> for PyFixedUnicode<N> {
     }
 }
 
-impl<const N: usize> PyClone for PyFixedUnicode<N> {
-    #[inline]
-    fn py_clone(&self, _py: Python<'_>) -> Self {
-        *self
-    }
-
-    #[inline]
-    fn vec_from_slice(_py: Python<'_>, slc: &[Self]) -> Vec<Self> {
-        slc.to_owned()
-    }
-
-    #[inline]
-    fn array_from_view<D>(
-        _py: Python<'_>,
-        view: ::ndarray::ArrayView<'_, Self, D>,
-    ) -> ::ndarray::Array<Self, D>
-    where
-        D: ::ndarray::Dimension,
-    {
-        view.to_owned()
-    }
-}
-
 unsafe impl<const N: usize> Element for PyFixedUnicode<N> {
     const IS_COPY: bool = true;
 
@@ -199,6 +155,8 @@ unsafe impl<const N: usize> Element for PyFixedUnicode<N> {
 
         unsafe { DTYPES.from_size(py, NPY_TYPES::NPY_UNICODE, b'=' as _, size_of::<Self>()) }
     }
+
+    clone_methods_impl!(Self);
 }
 
 struct TypeDescriptors {