API: Un-deprecate ArrayView::into_slice and deprecate ArrayView::to_slice

Looking closely at this one, it's actually clear why it should be called
into_slice (and why it was called so from the start).

There is already a general `ArrayBase::as_slice`.

1. `ArrayView<'a, _>::into_slice(self) -> Option<&'a [A]>` is an extra
feature on top of the generic `as_slice` because exactly: we preserve
the lifetime parameter from the view to the slice.

2. We relax the input parameter from `self` to `&self` because it makes
only makes the method apply in more places and copy less data

The "into" semantic is exactly that the lifetime parameter is preserved
from the array view into the slice. Clippy is just a robot, it didn't
understand this.

Author: bluss

src/impl_views/conversions.rs

@@ -31,7 +31,6 @@ where
 
     /// Return the array’s data as a slice, if it is contiguous and in standard order.
     /// Return `None` otherwise.
-    #[deprecated(note = "`into_slice` has been renamed to `to_slice`", since = "0.13.0")]
     #[allow(clippy::wrong_self_convention)]
     pub fn into_slice(&self) -> Option<&'a [A]> {
         if self.is_standard_layout() {
@@ -43,12 +42,9 @@ where
 
     /// Return the array’s data as a slice, if it is contiguous and in standard order.
     /// Return `None` otherwise.
+    #[deprecated(note = "`to-slice` has been deprecated in favour of `into_slice`", since = "0.15.0")]
     pub fn to_slice(&self) -> Option<&'a [A]> {
-        if self.is_standard_layout() {
-            unsafe { Some(slice::from_raw_parts(self.ptr.as_ptr(), self.len())) }
-        } else {
-            None
-        }
+        self.into_slice()
     }
 
     /// Converts to a raw array view.

src/iterators/mod.rs

@@ -279,7 +279,7 @@ where
 {
     pub(crate) fn new(self_: ArrayView<'a, A, D>) -> Self {
         Iter {
-            inner: if let Some(slc) = self_.to_slice() {
+            inner: if let Some(slc) = self_.into_slice() {
                 ElementsRepr::Slice(slc.iter())
             } else {
                 ElementsRepr::Counted(self_.into_elements_base())

src/lib.rs

@@ -996,7 +996,7 @@ pub type Ixs = isize;
 /// `Array<A, D>` | `Vec<A>` | [`.into_raw_vec()`](type.Array.html#method.into_raw_vec)<sup>[1](#into_raw_vec)</sup>
 /// `&ArrayBase<S, D>` | `&[A]` | [`.as_slice()`](#method.as_slice)<sup>[2](#req_contig_std)</sup>, [`.as_slice_memory_order()`](#method.as_slice_memory_order)<sup>[3](#req_contig)</sup>
 /// `&mut ArrayBase<S: DataMut, D>` | `&mut [A]` | [`.as_slice_mut()`](#method.as_slice_mut)<sup>[2](#req_contig_std)</sup>, [`.as_slice_memory_order_mut()`](#method.as_slice_memory_order_mut)<sup>[3](#req_contig)</sup>
-/// `ArrayView<A, D>` | `&[A]` | [`.to_slice()`](type.ArrayView.html#method.to_slice)<sup>[2](#req_contig_std)</sup>
+/// `ArrayView<A, D>` | `&[A]` | [`.into_slice()`](type.ArrayView.html#method.into_slice)<sup>[2](#req_contig_std)</sup>
 /// `ArrayViewMut<A, D>` | `&mut [A]` | [`.into_slice()`](type.ArrayViewMut.html#method.into_slice)<sup>[2](#req_contig_std)</sup>
 /// `Array0<A>` | `A` | [`.into_scalar()`](type.Array.html#method.into_scalar)
 ///