diff --git a/compiler/rustc_codegen_llvm/src/errors.rs b/compiler/rustc_codegen_llvm/src/errors.rs
index 6b7e38a6cb1..8db97d577ca 100644
--- a/compiler/rustc_codegen_llvm/src/errors.rs
+++ b/compiler/rustc_codegen_llvm/src/errors.rs
@@ -102,7 +102,7 @@ pub(crate) struct DlltoolFailImportLibrary<'a> {
 impl<G: EmissionGuarantee> IntoDiagnostic<'_, G> for ParseTargetMachineConfig<'_> {
     fn into_diagnostic(self, dcx: &'_ DiagCtxt, level: Level) -> DiagnosticBuilder<'_, G> {
         let diag: DiagnosticBuilder<'_, G> = self.0.into_diagnostic(dcx, level);
-        let (message, _) = diag.styled_message().first().expect("`LlvmError` with no message");
+        let (message, _) = diag.messages().first().expect("`LlvmError` with no message");
         let message = dcx.eagerly_translate_to_string(message.clone(), diag.args());
 
         let mut diag =
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index 0442bef8a44..dfe34dc3b72 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -986,7 +986,7 @@ pub(crate) enum Message<B: WriteBackendMethods> {
 type DiagnosticArgName<'source> = Cow<'source, str>;
 
 struct Diagnostic {
-    msg: Vec<(DiagnosticMessage, Style)>,
+    msgs: Vec<(DiagnosticMessage, Style)>,
     args: FxHashMap<DiagnosticArgName<'static>, rustc_errors::DiagnosticArgValue<'static>>,
     code: Option<DiagnosticId>,
     lvl: Level,
@@ -1799,14 +1799,14 @@ fn emit_diagnostic(&mut self, diag: &rustc_errors::Diagnostic) {
         let args: FxHashMap<Cow<'_, str>, rustc_errors::DiagnosticArgValue<'_>> =
             diag.args().map(|(name, arg)| (name.clone(), arg.clone())).collect();
         drop(self.sender.send(SharedEmitterMessage::Diagnostic(Diagnostic {
-            msg: diag.message.clone(),
+            msgs: diag.messages.clone(),
             args: args.clone(),
             code: diag.code.clone(),
             lvl: diag.level(),
         })));
         for child in &diag.children {
             drop(self.sender.send(SharedEmitterMessage::Diagnostic(Diagnostic {
-                msg: child.message.clone(),
+                msgs: child.messages.clone(),
                 args: args.clone(),
                 code: None,
                 lvl: child.level,
@@ -1838,7 +1838,7 @@ pub fn check(&self, sess: &Session, blocking: bool) {
             match message {
                 Ok(SharedEmitterMessage::Diagnostic(diag)) => {
                     let dcx = sess.dcx();
-                    let mut d = rustc_errors::Diagnostic::new_with_messages(diag.lvl, diag.msg);
+                    let mut d = rustc_errors::Diagnostic::new_with_messages(diag.lvl, diag.msgs);
                     if let Some(code) = diag.code {
                         d.code(code);
                     }
diff --git a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
index da266bf9c63..48e48f59a99 100644
--- a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
+++ b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
@@ -60,7 +60,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
 
         self.emit_messages_default(
             &diag.level,
-            &diag.message,
+            &diag.messages,
             &fluent_args,
             &diag.code,
             &primary_span,
diff --git a/compiler/rustc_errors/src/diagnostic.rs b/compiler/rustc_errors/src/diagnostic.rs
index 15b4704de10..1a5fc8757b7 100644
--- a/compiler/rustc_errors/src/diagnostic.rs
+++ b/compiler/rustc_errors/src/diagnostic.rs
@@ -103,7 +103,7 @@ pub struct Diagnostic {
     // outside of what methods in this crate themselves allow.
     pub(crate) level: Level,
 
-    pub message: Vec<(DiagnosticMessage, Style)>,
+    pub messages: Vec<(DiagnosticMessage, Style)>,
     pub code: Option<DiagnosticId>,
     pub span: MultiSpan,
     pub children: Vec<SubDiagnostic>,
@@ -161,7 +161,7 @@ pub enum DiagnosticId {
 #[derive(Clone, Debug, PartialEq, Hash, Encodable, Decodable)]
 pub struct SubDiagnostic {
     pub level: Level,
-    pub message: Vec<(DiagnosticMessage, Style)>,
+    pub messages: Vec<(DiagnosticMessage, Style)>,
     pub span: MultiSpan,
     pub render_span: Option<MultiSpan>,
 }
@@ -223,7 +223,7 @@ pub fn new<M: Into<DiagnosticMessage>>(level: Level, message: M) -> Self {
     pub fn new_with_messages(level: Level, messages: Vec<(DiagnosticMessage, Style)>) -> Self {
         Diagnostic {
             level,
-            message: messages,
+            messages,
             code: None,
             span: MultiSpan::new(),
             children: vec![],
@@ -905,7 +905,7 @@ pub fn get_code(&self) -> Option<DiagnosticId> {
     }
 
     pub fn set_primary_message(&mut self, msg: impl Into<DiagnosticMessage>) -> &mut Self {
-        self.message[0] = (msg.into(), Style::NoStyle);
+        self.messages[0] = (msg.into(), Style::NoStyle);
         self
     }
 
@@ -932,8 +932,8 @@ pub fn replace_args(
         self.args = args;
     }
 
-    pub fn styled_message(&self) -> &[(DiagnosticMessage, Style)] {
-        &self.message
+    pub fn messages(&self) -> &[(DiagnosticMessage, Style)] {
+        &self.messages
     }
 
     /// Helper function that takes a `SubdiagnosticMessage` and returns a `DiagnosticMessage` by
@@ -944,7 +944,7 @@ fn subdiagnostic_message_to_diagnostic_message(
         attr: impl Into<SubdiagnosticMessage>,
     ) -> DiagnosticMessage {
         let msg =
-            self.message.iter().map(|(msg, _)| msg).next().expect("diagnostic with no messages");
+            self.messages.iter().map(|(msg, _)| msg).next().expect("diagnostic with no messages");
         msg.with_subdiagnostic_message(attr.into())
     }
 
@@ -961,7 +961,7 @@ pub fn sub(
     ) {
         let sub = SubDiagnostic {
             level,
-            message: vec![(
+            messages: vec![(
                 self.subdiagnostic_message_to_diagnostic_message(message),
                 Style::NoStyle,
             )],
@@ -976,15 +976,15 @@ pub fn sub(
     fn sub_with_highlights<M: Into<SubdiagnosticMessage>>(
         &mut self,
         level: Level,
-        message: Vec<(M, Style)>,
+        messages: Vec<(M, Style)>,
         span: MultiSpan,
         render_span: Option<MultiSpan>,
     ) {
-        let message = message
+        let messages = messages
             .into_iter()
             .map(|m| (self.subdiagnostic_message_to_diagnostic_message(m.0), m.1))
             .collect();
-        let sub = SubDiagnostic { level, message, span, render_span };
+        let sub = SubDiagnostic { level, messages, span, render_span };
         self.children.push(sub);
     }
 
@@ -1002,7 +1002,7 @@ fn keys(
     ) {
         (
             &self.level,
-            &self.message,
+            &self.messages,
             self.args().collect(),
             &self.code,
             &self.span,
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs
index 3fb993c3651..78050889da3 100644
--- a/compiler/rustc_errors/src/emitter.rs
+++ b/compiler/rustc_errors/src/emitter.rs
@@ -350,7 +350,7 @@ fn fix_multispans_in_extern_macros_and_render_macro_backtrace(
 
                 children.push(SubDiagnostic {
                     level: Level::Note,
-                    message: vec![(DiagnosticMessage::from(msg), Style::NoStyle)],
+                    messages: vec![(DiagnosticMessage::from(msg), Style::NoStyle)],
                     span: MultiSpan::new(),
                     render_span: None,
                 });
@@ -533,7 +533,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
 
         self.emit_messages_default(
             &diag.level,
-            &diag.message,
+            &diag.messages,
             &fluent_args,
             &diag.code,
             &primary_span,
@@ -1228,10 +1228,10 @@ fn get_max_line_num(&mut self, span: &MultiSpan, children: &[SubDiagnostic]) ->
 
     /// Adds a left margin to every line but the first, given a padding length and the label being
     /// displayed, keeping the provided highlighting.
-    fn msg_to_buffer(
+    fn msgs_to_buffer(
         &self,
         buffer: &mut StyledBuffer,
-        msg: &[(DiagnosticMessage, Style)],
+        msgs: &[(DiagnosticMessage, Style)],
         args: &FluentArgs<'_>,
         padding: usize,
         label: &str,
@@ -1267,7 +1267,7 @@ fn style_or_override(style: Style, override_: Option<Style>) -> Style {
 
         // Provided the following diagnostic message:
         //
-        //     let msg = vec![
+        //     let msgs = vec![
         //       ("
         //       ("highlighted multiline\nstring to\nsee how it ", Style::NoStyle),
         //       ("looks", Style::Highlight),
@@ -1284,7 +1284,7 @@ fn style_or_override(style: Style, override_: Option<Style>) -> Style {
         //                see how it *looks* with
         //                very *weird* formats
         //                see?
-        for (text, style) in msg.iter() {
+        for (text, style) in msgs.iter() {
             let text = self.translate_message(text, args).map_err(Report::new).unwrap();
             let text = &normalize_whitespace(&text);
             let lines = text.split('\n').collect::<Vec<_>>();
@@ -1303,10 +1303,10 @@ fn style_or_override(style: Style, override_: Option<Style>) -> Style {
     }
 
     #[instrument(level = "trace", skip(self, args), ret)]
-    fn emit_message_default(
+    fn emit_messages_default_inner(
         &mut self,
         msp: &MultiSpan,
-        msg: &[(DiagnosticMessage, Style)],
+        msgs: &[(DiagnosticMessage, Style)],
         args: &FluentArgs<'_>,
         code: &Option<DiagnosticId>,
         level: &Level,
@@ -1327,7 +1327,7 @@ fn emit_message_default(
                 buffer.append(0, level.to_str(), Style::MainHeaderMsg);
                 buffer.append(0, ": ", Style::NoStyle);
             }
-            self.msg_to_buffer(&mut buffer, msg, args, max_line_num_len, "note", None);
+            self.msgs_to_buffer(&mut buffer, msgs, args, max_line_num_len, "note", None);
         } else {
             let mut label_width = 0;
             // The failure note level itself does not provide any useful diagnostic information
@@ -1360,7 +1360,7 @@ fn emit_message_default(
                 buffer.append(0, ": ", header_style);
                 label_width += 2;
             }
-            for (text, _) in msg.iter() {
+            for (text, _) in msgs.iter() {
                 let text = self.translate_message(text, args).map_err(Report::new).unwrap();
                 // Account for newlines to align output to its label.
                 for (line, text) in normalize_whitespace(&text).lines().enumerate() {
@@ -1747,7 +1747,7 @@ fn emit_suggestion_default(
         buffer.append(0, level.to_str(), Style::Level(*level));
         buffer.append(0, ": ", Style::HeaderMsg);
 
-        self.msg_to_buffer(
+        self.msgs_to_buffer(
             &mut buffer,
             &[(suggestion.msg.to_owned(), Style::NoStyle)],
             args,
@@ -2074,7 +2074,7 @@ fn emit_suggestion_default(
     fn emit_messages_default(
         &mut self,
         level: &Level,
-        message: &[(DiagnosticMessage, Style)],
+        messages: &[(DiagnosticMessage, Style)],
         args: &FluentArgs<'_>,
         code: &Option<DiagnosticId>,
         span: &MultiSpan,
@@ -2089,9 +2089,9 @@ fn emit_messages_default(
             num_decimal_digits(n)
         };
 
-        match self.emit_message_default(
+        match self.emit_messages_default_inner(
             span,
-            message,
+            messages,
             args,
             code,
             level,
@@ -2119,9 +2119,9 @@ fn emit_messages_default(
                 if !self.short_message {
                     for child in children {
                         let span = child.render_span.as_ref().unwrap_or(&child.span);
-                        if let Err(err) = self.emit_message_default(
+                        if let Err(err) = self.emit_messages_default_inner(
                             span,
-                            &child.message,
+                            &child.messages,
                             args,
                             &None,
                             &child.level,
@@ -2138,7 +2138,7 @@ fn emit_messages_default(
                                 // do not display this suggestion, it is meant only for tools
                             }
                             SuggestionStyle::HideCodeAlways => {
-                                if let Err(e) = self.emit_message_default(
+                                if let Err(e) = self.emit_messages_default_inner(
                                     &MultiSpan::new(),
                                     &[(sugg.msg.to_owned(), Style::HeaderMsg)],
                                     args,
diff --git a/compiler/rustc_errors/src/json.rs b/compiler/rustc_errors/src/json.rs
index aa3749334d9..624d96014f1 100644
--- a/compiler/rustc_errors/src/json.rs
+++ b/compiler/rustc_errors/src/json.rs
@@ -398,7 +398,7 @@ fn reset(&mut self) -> io::Result<()> {
         let output = Arc::try_unwrap(output.0).unwrap().into_inner().unwrap();
         let output = String::from_utf8(output).unwrap();
 
-        let translated_message = je.translate_messages(&diag.message, &args);
+        let translated_message = je.translate_messages(&diag.messages, &args);
         Diagnostic {
             message: translated_message.to_string(),
             code: DiagnosticCode::map_opt_string(diag.code.clone(), je),
@@ -419,7 +419,7 @@ fn from_sub_diagnostic(
         args: &FluentArgs<'_>,
         je: &JsonEmitter,
     ) -> Diagnostic {
-        let translated_message = je.translate_messages(&diag.message, args);
+        let translated_message = je.translate_messages(&diag.messages, args);
         Diagnostic {
             message: translated_message.to_string(),
             code: None,
diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs
index 3f86f275051..5ce79fad298 100644
--- a/compiler/rustc_errors/src/lib.rs
+++ b/compiler/rustc_errors/src/lib.rs
@@ -1551,7 +1551,7 @@ fn flush_delayed(
                     &mut out,
                     "delayed span bug: {}\n{}\n",
                     bug.inner
-                        .styled_message()
+                        .messages()
                         .iter()
                         .filter_map(|(msg, _)| msg.as_str())
                         .collect::<String>(),
diff --git a/compiler/rustc_expand/src/mbe/diagnostics.rs b/compiler/rustc_expand/src/mbe/diagnostics.rs
index cda3fa30a5b..b6718ec8c41 100644
--- a/compiler/rustc_expand/src/mbe/diagnostics.rs
+++ b/compiler/rustc_expand/src/mbe/diagnostics.rs
@@ -224,11 +224,11 @@ pub(super) fn emit_frag_parse_err(
 ) {
     // FIXME(davidtwco): avoid depending on the error message text
     if parser.token == token::Eof
-        && let DiagnosticMessage::Str(message) = &e.message[0].0
+        && let DiagnosticMessage::Str(message) = &e.messages[0].0
         && message.ends_with(", found `<eof>`")
     {
-        let msg = &e.message[0];
-        e.message[0] = (
+        let msg = &e.messages[0];
+        e.messages[0] = (
             DiagnosticMessage::from(format!(
                 "macro expansion ends with an incomplete expression: {}",
                 message.replace(", found `<eof>`", ""),
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index bd4a2998e2d..4bef67be3ef 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -3693,7 +3693,7 @@ fn smart_resolve_path_fragment(
             let mut parent_err = this.r.into_struct_error(parent_err.span, parent_err.node);
 
             // overwrite all properties with the parent's error message
-            err.message = take(&mut parent_err.message);
+            err.messages = take(&mut parent_err.messages);
             err.code = take(&mut parent_err.code);
             swap(&mut err.span, &mut parent_err.span);
             err.children = take(&mut parent_err.children);
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index e26ea7ee07b..01c734a004e 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1384,7 +1384,7 @@ fn suggest_add_reference_to_arg(
                     if has_custom_message {
                         err.note(msg);
                     } else {
-                        err.message =
+                        err.messages =
                             vec![(rustc_errors::DiagnosticMessage::from(msg), Style::NoStyle)];
                     }
                     let mut file = None;
diff --git a/src/librustdoc/passes/lint/check_code_block_syntax.rs b/src/librustdoc/passes/lint/check_code_block_syntax.rs
index ce42b9c204b..53c7f0f6e15 100644
--- a/src/librustdoc/passes/lint/check_code_block_syntax.rs
+++ b/src/librustdoc/passes/lint/check_code_block_syntax.rs
@@ -161,7 +161,7 @@ fn emit_diagnostic(&mut self, diag: &Diagnostic) {
 
         let fluent_args = to_fluent_args(diag.args());
         let translated_main_message = self
-            .translate_message(&diag.message[0].0, &fluent_args)
+            .translate_message(&diag.messages[0].0, &fluent_args)
             .unwrap_or_else(|e| panic!("{e}"));
 
         buffer.messages.push(format!("error from rustc: {translated_main_message}"));
diff --git a/src/tools/rustfmt/src/parse/session.rs b/src/tools/rustfmt/src/parse/session.rs
index e8f7b422ada..8303c03e1eb 100644
--- a/src/tools/rustfmt/src/parse/session.rs
+++ b/src/tools/rustfmt/src/parse/session.rs
@@ -370,7 +370,7 @@ fn emit_diagnostic(&mut self, _db: &Diagnostic) {
 
         fn build_diagnostic(level: DiagnosticLevel, span: Option<MultiSpan>) -> Diagnostic {
             let mut diag = Diagnostic::new(level, "");
-            diag.message.clear();
+            diag.messages.clear();
             if let Some(span) = span {
                 diag.span = span;
             }