## Summary This PR moves the "unused exception" rule out of the visitor and into a deferred check. When we can base rules solely on the semantic model, we probably should, as it greatly simplifies the `Checker` itself.
## Summary This PR moves the "unused exception" rule out of the visitor and into a deferred check. When we can base rules solely on the semantic model, we probably should, as it greatly simplifies the `Checker` itself.