diff --git a/src/spectator/matchers/start_with_matcher.cr b/src/spectator/matchers/start_with_matcher.cr
index 4de8700..5e0a16a 100644
--- a/src/spectator/matchers/start_with_matcher.cr
+++ b/src/spectator/matchers/start_with_matcher.cr
@@ -35,6 +35,7 @@ module Spectator::Matchers
 
     private def match_last(actual)
       list = actual.value.to_a
+    private def match_first(value, actual)
       first = list.first
 
       if expected.value === first