diff --git a/rtstartup/rsbegin.rs b/rtstartup/rsbegin.rs
index 9a3d95bd8ddfb..d3ff5c14aa4a8 100644
--- a/rtstartup/rsbegin.rs
+++ b/rtstartup/rsbegin.rs
@@ -19,6 +19,7 @@
 #![no_core]
 #![allow(non_camel_case_types)]
 #![allow(internal_features)]
+#![warn(unreachable_pub)]
 
 #[lang = "sized"]
 trait Sized {}
diff --git a/rtstartup/rsend.rs b/rtstartup/rsend.rs
index 2514eb0034402..81acfbed4477d 100644
--- a/rtstartup/rsend.rs
+++ b/rtstartup/rsend.rs
@@ -6,6 +6,7 @@
 #![crate_type = "rlib"]
 #![no_core]
 #![allow(internal_features)]
+#![warn(unreachable_pub)]
 
 #[lang = "sized"]
 trait Sized {}