diff --git a/src/rustc/rustdoc.rs b/src/rustc/rustdoc.rs
index 6fecd3a27a8a..ccedb9844bba 100644
--- a/src/rustc/rustdoc.rs
+++ b/src/rustc/rustdoc.rs
@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![feature(rustdoc)]
+#![feature(rustc_private)]
 
 extern crate rustdoc;