diff --git a/types/highland/highland-tests.ts b/types/highland/highland-tests.ts
index 5f1c734395..a1c48c944b 100644
--- a/types/highland/highland-tests.ts
+++ b/types/highland/highland-tests.ts
@@ -337,6 +337,8 @@ fooStream.toCallback((err: Error) => {});
 // UTILS
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+bool = _.isNil(x);
+
 bool = _.isStream(x);
 bool = _.isStream(fooStream);