Rollup merge of #152140 - bjorn3:driver_fixed_error_codes, r=jdonszelmann

Hard code the error code registry for custom drivers

And do some cleanups enabled by this.

Author: JonathanBrouwer

examples/rustc-interface-example.rs

@@ -4,14 +4,12 @@
 
 extern crate rustc_driver;
 extern crate rustc_error_codes;
-extern crate rustc_errors;
 extern crate rustc_hash;
 extern crate rustc_hir;
 extern crate rustc_interface;
 extern crate rustc_session;
 extern crate rustc_span;
 
-use rustc_errors::registry;
 use rustc_hash::FxHashMap;
 use rustc_session::config;
 
@@ -50,8 +48,6 @@ fn main() {
         //
         // The second parameter is local providers and the third parameter is external providers.
         override_queries: None, // Option<fn(&Session, &mut ty::query::Providers<'_>, &mut ty::query::Providers<'_>)>
-        // Registry of diagnostics codes.
-        registry: registry::Registry::new(rustc_errors::codes::DIAGNOSTICS),
         make_codegen_backend: None,
         expanded_args: Vec::new(),
         ice_file: None,

examples/rustc-interface-getting-diagnostics.rs

@@ -15,7 +15,7 @@ extern crate rustc_span;
 use std::sync::{Arc, Mutex};
 
 use rustc_errors::emitter::Emitter;
-use rustc_errors::registry::{self, Registry};
+use rustc_errors::registry::Registry;
 use rustc_errors::translation::Translate;
 use rustc_errors::{DiagInner, FluentBundle};
 use rustc_session::config;
@@ -76,7 +76,6 @@ fn main() {
         })),
         register_lints: None,
         override_queries: None,
-        registry: registry::Registry::new(rustc_errors::codes::DIAGNOSTICS),
         make_codegen_backend: None,
         expanded_args: Vec::new(),
         ice_file: None,