1 files changed, 9 insertions, 0 deletions
diff --git a/src/data/checks.js b/src/data/checks.js
index 88dfbc6d..fcafbaca 100644
--- a/src/data/checks.js
+++ b/src/data/checks.js
@@ -568,7 +568,16 @@ export function filterReferenceErrors(wikiData, {
                 break;
 
               default:
+                if (findFnKey.startsWith('_')) {
+                  throw new Error(`Unknown specially handled find function "${findFnKey}"`);
+                }
+
                 findFn = boundFind[findFnKey];
+
+                if (!findFn) {
+                  throw new Error(`Unknown find function "${findFnKey}"`);
+                }
+
                 break;
             }