diff --git a/src/lib.rs b/src/lib.rs
index 03f41d197b8..007d61ed51d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -18,6 +18,8 @@
 #![recursion_limit="256"]
 #![warn(rust_2018_idioms)]
 #![warn(unused_lifetimes)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 extern crate rustc_apfloat;
 extern crate rustc_ast;