Add lint for diagnostic migration

Author: naritanara

compiler/rustc_passes/src/lib.rs

@@ -5,6 +5,8 @@
 //! This API is completely unstable and subject to change.
 
 #![allow(rustc::potential_query_instability)]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(iter_intersperse)]
 #![feature(let_chains)]