error: use of `offset` with a `usize` casted to an `isize`
  --> $DIR/ptr_offset_with_cast.rs:10:9
   |
10 |         ptr.offset(offset_usize as isize);
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `ptr.add(offset_usize)`
   |
   = note: `-D ptr-offset-with-cast` implied by `-D warnings`

error: aborting due to previous error