diff --git a/rust/src/fileio_asyncio.rs b/rust/src/fileio_asyncio.rs
index a5d45d34d..067182da0 100644
--- a/rust/src/fileio_asyncio.rs
+++ b/rust/src/fileio_asyncio.rs
@@ -631,7 +631,7 @@ const _: () = {
     );
     assert!(
         std::mem::offset_of!(FIO_rust_decompress_file_projection_t, decompress)
-            == FIO_RUST_DECOMPRESS_FILE_CALLBACK_OFFSET + 8 * size_of::<usize>()
+            == FIO_RUST_DECOMPRESS_FILE_CALLBACK_OFFSET + usize::BITS as usize
     );
     assert!(
         std::mem::offset_of!(FIO_rust_decompress_file_projection_t, clear_handler)