diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index 0f07de43e80..c17b85db3b0 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -1,3 +1,7 @@
+// tidy-alphabetical-start
+#![warn(unreachable_pub)]
+// tidy-alphabetical-end
+
 use rustc_ast::node_id::NodeId;
 use rustc_ast::{AttrId, Attribute};
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};