diff --git a/lib/algorithm.js b/lib/algorithm.js
index 0794bec..6069251 100644
--- a/lib/algorithm.js
+++ b/lib/algorithm.js
@@ -101,8 +101,10 @@ class Algorithm {
         return this.#wantNewestRange(localHave, remoteHave, goal.count)
 
       case 'none':
-      default:
         return EMPTY_RANGE
+
+      default:
+        throw new Error(`Unrecognized goal type: ${goal.type}`)
     }
   }