refactor: remove the uses of Box::into_raw_non_null

`Box::into_raw_non_null` was recently deprecated by
<rust-lang/rust#71168> and will probably be
removed after some time.

support/atom2/src/lib.rs

@@ -1,7 +1,6 @@
 //! Reimplementation of the [atom] library with specialized and extended features.
 //!
 //! [atom]: https://crates.io/crates/atom
-#![feature(box_into_raw_non_null)]
 #![feature(const_fn)] // `const fn` with a constrained type parameter (e.g., `T: PtrSized`)
 use std::cell::Cell;
 use std::marker::PhantomData;
@@ -85,7 +84,7 @@ impl<T: PtrSized> PtrSizedExt for T {
 
 unsafe impl<T> PtrSized for Box<T> {
     fn into_raw(this: Self) -> NonNull<()> {
-        unsafe { mem::transmute(Box::into_raw_non_null(this)) }
+        NonNull::from(Box::leak(this)).cast()
     }
     unsafe fn from_raw(ptr: NonNull<()>) -> Self {
         Box::from_raw(ptr.as_ptr() as _)

support/neo_linked_list/src/lib.rs

@@ -1,5 +1,4 @@
 //! Provides a customized version of `std::collections::LinkedList`.
-#![feature(box_into_raw_non_null)]
 pub mod cell;
 pub mod linked_list;
 

support/neo_linked_list/src/linked_list.rs

@@ -177,9 +177,7 @@ impl<T: ?Sized> Node<T> {
     fn box_into_hdr(mut self: Box<Self>) -> NonNull<Hdr> {
         self.set_vtable();
 
-        let mut raw = Box::into_raw_non_null(self);
-
-        NonNull::from(unsafe { &mut raw.as_mut().hdr })
+        NonNull::from(&mut Box::leak(self).hdr)
     }
 
     #[inline]