diff --git a/compiler/rustc_data_structures/src/sync/lock.rs b/compiler/rustc_data_structures/src/sync/lock.rs
index 040a8aa6b63..756984642c7 100644
--- a/compiler/rustc_data_structures/src/sync/lock.rs
+++ b/compiler/rustc_data_structures/src/sync/lock.rs
@@ -189,6 +189,7 @@ mod no_sync {
     use super::Mode;
     use std::cell::RefCell;
 
+    #[doc(no_inline)]
     pub use std::cell::RefMut as LockGuard;
 
     pub struct Lock<T>(RefCell<T>);