Cleanup errors handlers even more

compiler/rustc_borrowck/src/lib.rs

@@ -2502,8 +2502,8 @@ mod error {
             if !self.errors.buffered.is_empty() {
                 self.errors.buffered.sort_by_key(|diag| diag.sort_span);
 
-                for mut diag in self.errors.buffered.drain(..) {
-                    self.infcx.tcx.sess.diagnostic().emit_diagnostic(&mut diag);
+                for diag in self.errors.buffered.drain(..) {
+                    self.infcx.tcx.sess.diagnostic().emit_diagnostic(diag);
                 }
             }
 

compiler/rustc_builtin_macros/src/errors.rs

@@ -453,7 +453,7 @@ impl<'a> IntoDiagnostic<'a> for EnvNotDefinedWithUserMessage {
             rustc::untranslatable_diagnostic,
             reason = "cannot translate user-provided messages"
         )]
-        let mut diag = handler.struct_diagnostic(self.msg_from_user.to_string());
+        let mut diag = handler.struct_err(self.msg_from_user.to_string());
         diag.set_span(self.span);
         diag
     }
@@ -804,7 +804,7 @@ pub(crate) struct AsmClobberNoReg {
 impl<'a> IntoDiagnostic<'a> for AsmClobberNoReg {
     fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'a, ErrorGuaranteed> {
         let mut diag =
-            handler.struct_diagnostic(crate::fluent_generated::builtin_macros_asm_clobber_no_reg);
+            handler.struct_err(crate::fluent_generated::builtin_macros_asm_clobber_no_reg);
         diag.set_span(self.spans.clone());
         // eager translation as `span_labels` takes `AsRef<str>`
         let lbl1 = handler.eagerly_translate_to_string(

compiler/rustc_codegen_llvm/src/errors.rs

@@ -107,7 +107,8 @@ impl IntoDiagnostic<'_, FatalError> for ParseTargetMachineConfig<'_> {
         let (message, _) = diag.styled_message().first().expect("`LlvmError` with no message");
         let message = handler.eagerly_translate_to_string(message.clone(), diag.args());
 
-        let mut diag = handler.struct_diagnostic(fluent::codegen_llvm_parse_target_machine_config);
+        let mut diag =
+            handler.struct_almost_fatal(fluent::codegen_llvm_parse_target_machine_config);
         diag.set_arg("error", message);
         diag
     }

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -1848,7 +1848,7 @@ impl SharedEmitterMain {
                         d.code(code);
                     }
                     d.replace_args(diag.args);
-                    handler.emit_diagnostic(&mut d);
+                    handler.emit_diagnostic(d);
                 }
                 Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => {
                     let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string();

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -277,8 +277,8 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
         // "secondary" errors if they occurred.
         let secondary_errors = mem::take(&mut self.secondary_errors);
         if self.error_emitted.is_none() {
-            for mut error in secondary_errors {
-                self.tcx.sess.diagnostic().emit_diagnostic(&mut error);
+            for error in secondary_errors {
+                self.tcx.sess.diagnostic().emit_diagnostic(error);
             }
         } else {
             assert!(self.tcx.sess.has_errors().is_some());

compiler/rustc_errors/src/diagnostic_builder.rs

@@ -132,7 +132,7 @@ impl EmissionGuarantee for ErrorGuaranteed {
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
 
-                let guar = handler.emit_diagnostic(&mut db.inner.diagnostic);
+                let guar = handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
 
                 // Only allow a guarantee if the `level` wasn't switched to a
                 // non-error - the field isn't `pub`, but the whole `Diagnostic`
@@ -181,7 +181,7 @@ impl EmissionGuarantee for () {
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
 
-                handler.emit_diagnostic(&mut db.inner.diagnostic);
+                handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
             }
             // `.emit()` was previously called, disallowed from repeating it.
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
@@ -207,7 +207,7 @@ impl EmissionGuarantee for Noted {
             // First `.emit()` call, the `&Handler` is still available.
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
-                handler.emit_diagnostic(&mut db.inner.diagnostic);
+                handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
             }
             // `.emit()` was previously called, disallowed from repeating it.
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
@@ -236,7 +236,7 @@ impl EmissionGuarantee for Bug {
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
 
-                handler.emit_diagnostic(&mut db.inner.diagnostic);
+                handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
             }
             // `.emit()` was previously called, disallowed from repeating it.
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
@@ -260,7 +260,7 @@ impl EmissionGuarantee for ! {
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
 
-                handler.emit_diagnostic(&mut db.inner.diagnostic);
+                handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
             }
             // `.emit()` was previously called, disallowed from repeating it.
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
@@ -284,7 +284,7 @@ impl EmissionGuarantee for rustc_span::fatal_error::FatalError {
             DiagnosticBuilderState::Emittable(handler) => {
                 db.inner.state = DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation;
 
-                handler.emit_diagnostic(&mut db.inner.diagnostic);
+                handler.emit_diagnostic_without_consuming(&mut db.inner.diagnostic);
             }
             // `.emit()` was previously called, disallowed from repeating it.
             DiagnosticBuilderState::AlreadyEmittedOrDuringCancellation => {}
@@ -365,7 +365,9 @@ impl<'a, G: EmissionGuarantee> DiagnosticBuilder<'a, G> {
         }
     }
 
-    /// Emit the diagnostic.
+    /// Emit the diagnostic. Does not consume `self`, which may be surprising,
+    /// but there are various places that rely on continuing to use `self`
+    /// after calling `emit`.
     #[track_caller]
     pub fn emit(&mut self) -> G {
         G::diagnostic_builder_emit_producing_guarantee(self)
@@ -640,13 +642,13 @@ impl Drop for DiagnosticBuilderInner<'_> {
             // No `.emit()` or `.cancel()` calls.
             DiagnosticBuilderState::Emittable(handler) => {
                 if !panicking() {
-                    handler.emit_diagnostic(&mut Diagnostic::new(
+                    handler.emit_diagnostic(Diagnostic::new(
                         Level::Bug,
                         DiagnosticMessage::from(
                             "the following error was constructed but not emitted",
                         ),
                     ));
-                    handler.emit_diagnostic(&mut self.diagnostic);
+                    handler.emit_diagnostic_without_consuming(&mut self.diagnostic);
                     panic!("error was constructed but not emitted");
                 }
             }

compiler/rustc_errors/src/emitter.rs

@@ -581,7 +581,7 @@ impl Emitter for SilentEmitter {
             if let Some(ref note) = self.fatal_note {
                 d.note(note.clone());
             }
-            self.fatal_handler.emit_diagnostic(&mut d);
+            self.fatal_handler.emit_diagnostic(d);
         }
     }
 }