diff --git a/src/lib.rs b/src/lib.rs
index bf06c8b..09278d7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,6 +3,7 @@
 #![feature(decl_macro)]
 #![feature(iter_array_chunks)]
 #![feature(binary_heap_into_iter_sorted)]
+#![feature(type_alias_impl_trait)]
 
 pub mod days;
 pub mod utils;