Use fallback fluent bundle from inner emitter in SilentEmitter

compiler/rustc_errors/src/emitter.rs

@@ -540,7 +540,6 @@ impl Emitter for HumanEmitter {
 /// Fatal diagnostics are forwarded to `fatal_emitter` to avoid silent
 /// failures of rustc, as witnessed e.g. in issue #89358.
 pub struct SilentEmitter {
-    pub fallback_bundle: LazyFallbackBundle,
     pub fatal_emitter: Box<dyn Emitter + DynSend>,
     pub fatal_note: Option<String>,
     pub emit_fatal_diagnostic: bool,
@@ -552,9 +551,7 @@ impl Translate for SilentEmitter {
     }
 
     fn fallback_fluent_bundle(&self) -> &FluentBundle {
-        // Ideally this field wouldn't be necessary and the fallback bundle in `fatal_dcx` would be
-        // used but the lock prevents this.
-        &self.fallback_bundle
+        self.fatal_emitter.fallback_fluent_bundle()
     }
 }
 

compiler/rustc_errors/src/lib.rs

@@ -676,12 +676,7 @@ impl DiagCtxt {
         Self { inner: Lock::new(DiagCtxtInner::new(emitter)) }
     }
 
-    pub fn make_silent(
-        &self,
-        fallback_bundle: LazyFallbackBundle,
-        fatal_note: Option<String>,
-        emit_fatal_diagnostic: bool,
-    ) {
+    pub fn make_silent(&self, fatal_note: Option<String>, emit_fatal_diagnostic: bool) {
         // An empty type that implements `Emitter` to temporarily swap in place of the real one,
         // which will be used in constructing its replacement.
         struct FalseEmitter;
@@ -710,7 +705,6 @@ impl DiagCtxt {
         let mut prev_emitter = Box::new(FalseEmitter) as Box<dyn Emitter + DynSend>;
         std::mem::swap(&mut inner.emitter, &mut prev_emitter);
         let new_emitter = Box::new(emitter::SilentEmitter {
-            fallback_bundle,
             fatal_emitter: prev_emitter,
             fatal_note,
             emit_fatal_diagnostic,

compiler/rustc_session/src/parse.rs

@@ -277,12 +277,9 @@ impl ParseSess {
     ) -> Self {
         let fallback_bundle = fallback_fluent_bundle(locale_resources, false);
         let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
-        let fatal_emitter = Box::new(HumanEmitter::new(
-            stderr_destination(ColorConfig::Auto),
-            Lrc::clone(&fallback_bundle),
-        ));
+        let fatal_emitter =
+            Box::new(HumanEmitter::new(stderr_destination(ColorConfig::Auto), fallback_bundle));
         let dcx = DiagCtxt::new(Box::new(SilentEmitter {
-            fallback_bundle,
             fatal_emitter,
             fatal_note: Some(fatal_note),
             emit_fatal_diagnostic,

src/tools/rustfmt/src/parse/session.rs

@@ -114,13 +114,12 @@ fn default_dcx(
         false,
     );
     let emitter = Box::new(
-        HumanEmitter::new(stderr_destination(emit_color), fallback_bundle.clone())
+        HumanEmitter::new(stderr_destination(emit_color), fallback_bundle)
             .sm(Some(source_map.clone())),
     );
 
     let emitter: Box<DynEmitter> = if !show_parse_errors {
         Box::new(SilentEmitter {
-            fallback_bundle,
             fatal_emitter: emitter,
             fatal_note: None,
             emit_fatal_diagnostic: false,
@@ -205,16 +204,7 @@ impl ParseSess {
     }
 
     pub(crate) fn set_silent_emitter(&mut self) {
-        // Ideally this invocation wouldn't be necessary and the fallback bundle in
-        // `self.parse_sess.dcx` could be used, but the lock in `DiagCtxt` prevents this.
-        // See `<rustc_errors::SilentEmitter as Translate>::fallback_fluent_bundle`.
-        let fallback_bundle = rustc_errors::fallback_fluent_bundle(
-            rustc_driver::DEFAULT_LOCALE_RESOURCES.to_vec(),
-            false,
-        );
-        self.raw_psess
-            .dcx()
-            .make_silent(fallback_bundle, None, false);
+        self.raw_psess.dcx().make_silent(None, false);
     }
 
     pub(crate) fn span_to_filename(&self, span: Span) -> FileName {