Extract SilentEmitter

Author: camsteffen

compiler/rustc_errors/src/emitter.rs

@@ -536,7 +536,6 @@ impl Emitter for HumanEmitter {
 pub struct FatalEmitter {
     pub fatal_emitter: Box<dyn Emitter + DynSend>,
     pub fatal_note: Option<String>,
-    pub emit_fatal_diagnostic: bool,
 }
 
 impl Emitter for FatalEmitter {
@@ -545,7 +544,7 @@ impl Emitter for FatalEmitter {
     }
 
     fn emit_diagnostic(&mut self, mut diag: DiagInner, registry: &Registry) {
-        if self.emit_fatal_diagnostic && diag.level == Level::Fatal {
+        if diag.level == Level::Fatal {
             if let Some(fatal_note) = &self.fatal_note {
                 diag.sub(Level::Note, fatal_note.clone(), MultiSpan::new());
             }
@@ -558,6 +557,22 @@ impl Emitter for FatalEmitter {
     }
 }
 
+pub struct SilentEmitter {
+    pub translator: Translator,
+}
+
+impl Emitter for SilentEmitter {
+    fn source_map(&self) -> Option<&SourceMap> {
+        None
+    }
+
+    fn emit_diagnostic(&mut self, _diag: DiagInner, _registry: &Registry) {}
+
+    fn translator(&self) -> &Translator {
+        &self.translator
+    }
+}
+
 /// Maximum number of suggestions to be shown
 ///
 /// Arbitrary, but taken from trait import suggestion limit

compiler/rustc_errors/src/lib.rs

@@ -744,34 +744,10 @@ impl DiagCtxt {
         Self { inner: Lock::new(DiagCtxtInner::new(emitter)) }
     }
 
-    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;
-
-        impl Emitter for FalseEmitter {
-            fn emit_diagnostic(&mut self, _: DiagInner, _: &Registry) {
-                unimplemented!("false emitter must only used during `make_silent`")
-            }
-
-            fn source_map(&self) -> Option<&SourceMap> {
-                unimplemented!("false emitter must only used during `make_silent`")
-            }
-
-            fn translator(&self) -> &translation::Translator {
-                unimplemented!("false emitter must only used during `make_silent`")
-            }
-        }
-
+    pub fn make_silent(&self) {
         let mut inner = self.inner.borrow_mut();
-        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::FatalEmitter {
-            fatal_emitter: prev_emitter,
-            fatal_note,
-            emit_fatal_diagnostic,
-        });
-        inner.emitter = new_emitter;
+        let translator = inner.emitter.translator().clone();
+        inner.emitter = Box::new(emitter::SilentEmitter { translator });
     }
 
     pub fn set_emitter(&self, emitter: Box<dyn Emitter + DynSend>) {

compiler/rustc_interface/src/interface.rs

@@ -55,7 +55,6 @@ pub(crate) fn parse_cfg(dcx: DiagCtxtHandle<'_>, cfgs: Vec<String>) -> Cfg {
             let psess = ParseSess::with_fatal_emitter(
                 vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
                 format!("this error occurred on the command line: `--cfg={s}`"),
-                true,
             );
             let filename = FileName::cfg_spec_source_code(&s);
 
@@ -119,7 +118,6 @@ pub(crate) fn parse_check_cfg(dcx: DiagCtxtHandle<'_>, specs: Vec<String>) -> Ch
         let psess = ParseSess::with_fatal_emitter(
             vec![crate::DEFAULT_LOCALE_RESOURCE, rustc_parse::DEFAULT_LOCALE_RESOURCE],
             format!("this error occurred on the command line: `--check-cfg={s}`"),
-            true,
         );
         let filename = FileName::cfg_spec_source_code(&s);
 

compiler/rustc_session/src/parse.rs

@@ -275,22 +275,14 @@ impl ParseSess {
         }
     }
 
-    pub fn with_fatal_emitter(
-        locale_resources: Vec<&'static str>,
-        fatal_note: String,
-
-        emit_fatal_diagnostic: bool,
-    ) -> Self {
+    pub fn with_fatal_emitter(locale_resources: Vec<&'static str>, fatal_note: String) -> Self {
         let translator = Translator::with_fallback_bundle(locale_resources, false);
         let sm = Arc::new(SourceMap::new(FilePathMapping::empty()));
         let fatal_emitter =
             Box::new(HumanEmitter::new(stderr_destination(ColorConfig::Auto), translator));
-        let dcx = DiagCtxt::new(Box::new(FatalEmitter {
-            fatal_emitter,
-            fatal_note: Some(fatal_note),
-            emit_fatal_diagnostic,
-        }))
-        .disable_warnings();
+        let dcx =
+            DiagCtxt::new(Box::new(FatalEmitter { fatal_emitter, fatal_note: Some(fatal_note) }))
+                .disable_warnings();
         ParseSess::with_dcx(dcx, sm)
     }
 

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

@@ -3,7 +3,7 @@ use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
 
 use rustc_data_structures::sync::IntoDynSyncSend;
-use rustc_errors::emitter::{DynEmitter, Emitter, HumanEmitter, FatalEmitter, stderr_destination};
+use rustc_errors::emitter::{DynEmitter, Emitter, HumanEmitter, SilentEmitter, stderr_destination};
 use rustc_errors::registry::Registry;
 use rustc_errors::translation::Translator;
 use rustc_errors::{ColorConfig, Diag, DiagCtxt, DiagInner, Level as DiagnosticLevel};
@@ -105,19 +105,14 @@ fn default_dcx(
     };
 
     let translator = rustc_driver::default_translator();
-    let emitter = Box::new(
-        HumanEmitter::new(stderr_destination(emit_color), translator)
-            .sm(Some(source_map.clone())),
-    );
-
-    let emitter: Box<DynEmitter> = if !show_parse_errors {
-        Box::new(FatalEmitter {
-            fatal_emitter: emitter,
-            fatal_note: None,
-            emit_fatal_diagnostic: false,
-        })
+
+    let emitter: Box<DynEmitter> = if show_parse_errors {
+        Box::new(
+            HumanEmitter::new(stderr_destination(emit_color), translator)
+                .sm(Some(source_map.clone())),
+        )
     } else {
-        emitter
+        Box::new(SilentEmitter { translator })
     };
     DiagCtxt::new(Box::new(SilentOnIgnoredFilesEmitter {
         has_non_ignorable_parser_errors: false,
@@ -196,7 +191,7 @@ impl ParseSess {
     }
 
     pub(crate) fn set_silent_emitter(&mut self) {
-        self.raw_psess.dcx().make_silent(None, false);
+        self.raw_psess.dcx().make_silent();
     }
 
     pub(crate) fn span_to_filename(&self, span: Span) -> FileName {