diff --git a/src/lib.rs b/src/lib.rs
index 330147c8f1..f089d1e1bc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,5 @@
 #![feature(rustc_private)]
 #![feature(cell_update)]
-#![feature(const_option)]
 #![feature(float_gamma)]
 #![feature(map_try_insert)]
 #![feature(never_type)]