message: Add allow(dead_code) in the Stack module
  Summary: Reasons in the comment
diff: * limitations under the License.
  */
  +// This module contains stack-like data structures that tend to be super
  +// useful when writing an interpreter. As we refactor, various types
  +// and methods become used/unused on a fairly regular basis. Rather than
  +// trying to fight the dead-code checker, just give up for this module.
  +// Once everything is stable, it might be worth removing what we don't need.
  +#![allow(dead_code)]
  +
  use std::{iter, mem};
  #[derive(Default)]
  