Use `mul nuw nsw` in `intrinsics::copy` Essentially the same as rust-lang/rust#157560, just for `copy` instead of `copy_nonoverlapping`. > Yeah, in fact both copy and copy_nonoverlapping could use this since we know the result must be at most isize::MAX else it cannot be inbounds. > ~ https://github.com/rust-lang/rust/pull/157560#issuecomment-4642072687 r? saethlin