diff --git a/library/std/src/os/hermit/mod.rs b/library/std/src/os/hermit/mod.rs
index 02a4b2c3ab5e7..5812206a25759 100644
--- a/library/std/src/os/hermit/mod.rs
+++ b/library/std/src/os/hermit/mod.rs
@@ -1,4 +1,5 @@
 #![stable(feature = "rust1", since = "1.0.0")]
+#![deny(unsafe_op_in_unsafe_fn)]
 
 #[allow(unused_extern_crates)]
 #[stable(feature = "rust1", since = "1.0.0")]