Update src/base/storage.rs

Co-authored-by: tpdickso <terence.dickson.prf@gmail.com>

src/base/storage.rs

@@ -206,6 +206,14 @@ pub unsafe trait RawStorageMut<T, R: Dim, C: Dim = U1>: RawStorage<T, R, C> {
     ///
     /// # Safety
     /// If the indices are out of bounds, the method will cause undefined behavior.
+    /// 
+    /// # Validity
+    /// The default implementation of this trait function is only guaranteed to be
+    /// sound if invocations of `self.ptr_mut()` and `self.get_address_unchecked_linear_mut()`
+    /// result in stable references. If any of the data pointed to by these trait methods
+    /// moves as a consequence of invoking either of these methods then this default
+    /// trait implementation may be invalid or unsound and should be overridden.
+    
     #[inline]
     unsafe fn swap_unchecked_linear(&mut self, i1: usize, i2: usize) {
         // we can't just use the pointers returned from `get_address_unchecked_linear_mut` because calling a