diff --git a/src/lib.rs b/src/lib.rs
index 13d09c2..c9e968e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -12,6 +12,7 @@ This structure should implement the following:
 
 #![forbid(unconditional_recursion, future_incompatible)]
 #![deny(unsafe_code)]
+#![feature(offset_of)]
 
 #[allow(unsafe_code)]
 mod green;