document safety requirements on WeakArrayMut<'a, T, N>

Author: folkertdev

zlib-rs/src/weak_slice.rs

@@ -71,6 +71,14 @@ pub(crate) struct WeakArrayMut<'a, T, const N: usize> {
 }
 
 impl<'a, T, const N: usize> WeakArrayMut<'a, T, N> {
+    /// # Safety
+    ///
+    /// The arguments must satisfy the requirements of [`pointer::as_mut`]. The
+    /// difference versus a `&mut [T; N]` is that the safety requirements are only enforced when a reference is
+    /// needed, so in practice we mostly get the convenient slice APIs,
+    /// without the exact correctness constraints of a rust core/std mutable reference.
+    ///
+    /// [`pointer::as_mut`]: https://doc.rust-lang.org/core/primitive.pointer.html#method.as_mut
     pub(crate) unsafe fn from_ptr(ptr: *mut [T; N]) -> Self {
         Self {
             ptr,