diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 076d56fb80842..3ffe7a7a8cf67 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -118,6 +118,7 @@ pub struct Session {
/// injected.
pub injected_allocator: Once