diff --git a/prelude.ld b/prelude.ld
index 936a34b..fefbf93 100644
--- a/prelude.ld
+++ b/prelude.ld
@@ -326,6 +326,7 @@ fn join {
 	([]) -> ""
 	([str as :string]) -> str
 	(strs as :list) -> join (strs, "")
+	([], separator as :string) -> ""
 	([str as :string], separator as :string) -> str
 	([str, ...strs], separator as :string) -> fold (
 		fn (joined, to_join) -> concat (joined, separator, to_join)