diff --git a/syntax/mod.rs b/syntax/mod.rs
index b742e37..33ed31c 100644
--- a/syntax/mod.rs
+++ b/syntax/mod.rs
@@ -20,6 +20,7 @@
 pub mod set;
 pub mod symbol;
 mod tokens;
+mod toposort;
 pub mod types;
 
 use self::discriminant::Discriminant;