Module chalk_ir::zip

Traits for “zipping” types, walking through two structures and checking that they match.

Traits

• Zip
  The Zip trait walks two values, invoking the Zipper methods where appropriate, but otherwise requiring strict equality.
• Zipper
  When we zip types, we basically traverse the structure, ensuring that it matches. When we come to types/lifetimes, we invoke the callback methods in the zipper to match them up. Primarily used during unification or similar operations.