I'm getting the following compiler warning:

```
File "lib/Dehop.ml", line 967, characters 31-160:
Warning 8: this pattern-matching is not exhaustive.
Here is an example of a value that is not matched:
(Mod (_, _)|Par (_, _)|Choice (_, _)|Star _|Link (_, _, _, _))
```

Is there an appropriate catch-all for this?