trait AsMutPtr: impl AsMutPtr for Box<[_]>.

src/disjoint_mut.rs

@@ -23,6 +23,7 @@ use std::ops::RangeInclusive;
 use std::ops::RangeTo;
 use std::ops::RangeToInclusive;
 use std::ptr;
+use std::ptr::addr_of_mut;
 
 use crate::src::align::AlignedByteChunk;
 use crate::src::align::AlignedVec;
@@ -604,6 +605,19 @@ unsafe impl<V> AsMutPtr for [V] {
     }
 }
 
+unsafe impl<V> AsMutPtr for Box<[V]> {
+    type Target = V;
+
+    unsafe fn as_mut_ptr(ptr: *mut Self) -> *mut Self::Target {
+        // SAFETY: `AsMutPtr::as_mut_ptr` may derefence `ptr`.
+        unsafe { addr_of_mut!(**ptr) }.cast()
+    }
+
+    fn len(&self) -> usize {
+        (**self).len()
+    }
+}
+
 impl<V: Copy, C: AlignedByteChunk> DisjointMut<AlignedVec<V, C>> {
     pub fn resize(&mut self, new_len: usize, value: V) {
         self.inner.get_mut().resize(new_len, value)