Add note_once/help_once to diagnostic derives

compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs

@@ -158,7 +158,9 @@ impl DiagnosticDeriveVariantBuilder {
         let slug = subdiag.slug.unwrap_or_else(|| match subdiag.kind {
             SubdiagnosticKind::Label => parse_quote! { _subdiag::label },
             SubdiagnosticKind::Note => parse_quote! { _subdiag::note },
+            SubdiagnosticKind::NoteOnce => parse_quote! { _subdiag::note_once },
             SubdiagnosticKind::Help => parse_quote! { _subdiag::help },
+            SubdiagnosticKind::HelpOnce => parse_quote! { _subdiag::help_once },
             SubdiagnosticKind::Warn => parse_quote! { _subdiag::warn },
             SubdiagnosticKind::Suggestion { .. } => parse_quote! { _subdiag::suggestion },
             SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(),
@@ -233,9 +235,11 @@ impl DiagnosticDeriveVariantBuilder {
         };
         let fn_ident = format_ident!("{}", subdiag);
         match subdiag {
-            SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
+            SubdiagnosticKind::Note
-                Ok(self.add_subdiagnostic(&fn_ident, slug))
+            | SubdiagnosticKind::NoteOnce
-            }
+            | SubdiagnosticKind::Help
+            | SubdiagnosticKind::HelpOnce
+            | SubdiagnosticKind::Warn => Ok(self.add_subdiagnostic(&fn_ident, slug)),
             SubdiagnosticKind::Label | SubdiagnosticKind::Suggestion { .. } => {
                 throw_invalid_attr!(attr, |diag| diag
                     .help("`#[label]` and `#[suggestion]` can only be applied to fields"));
@@ -347,7 +351,11 @@ impl DiagnosticDeriveVariantBuilder {
                 report_error_if_not_applied_to_span(attr, &info)?;
                 Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug))
             }
-            SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => {
+            SubdiagnosticKind::Note
+            | SubdiagnosticKind::NoteOnce
+            | SubdiagnosticKind::Help
+            | SubdiagnosticKind::HelpOnce
+            | SubdiagnosticKind::Warn => {
                 let inner = info.ty.inner_type();
                 if type_matches_path(inner, &["rustc_span", "Span"])
                     || type_matches_path(inner, &["rustc_span", "MultiSpan"])

compiler/rustc_macros/src/diagnostics/utils.rs

@@ -575,8 +575,12 @@ pub(super) enum SubdiagnosticKind {
     Label,
     /// `#[note(...)]`
     Note,
+    /// `#[note_once(...)]`
+    NoteOnce,
     /// `#[help(...)]`
     Help,
+    /// `#[help_once(...)]`
+    HelpOnce,
     /// `#[warning(...)]`
     Warn,
     /// `#[suggestion{,_short,_hidden,_verbose}]`
@@ -624,7 +628,9 @@ impl SubdiagnosticVariant {
         let mut kind = match name {
             "label" => SubdiagnosticKind::Label,
             "note" => SubdiagnosticKind::Note,
+            "note_once" => SubdiagnosticKind::NoteOnce,
             "help" => SubdiagnosticKind::Help,
+            "help_once" => SubdiagnosticKind::HelpOnce,
             "warning" => SubdiagnosticKind::Warn,
             _ => {
                 // Recover old `#[(multipart_)suggestion_*]` syntaxes
@@ -682,7 +688,9 @@ impl SubdiagnosticVariant {
                 match kind {
                     SubdiagnosticKind::Label
                     | SubdiagnosticKind::Note
+                    | SubdiagnosticKind::NoteOnce
                     | SubdiagnosticKind::Help
+                    | SubdiagnosticKind::HelpOnce
                     | SubdiagnosticKind::Warn
                     | SubdiagnosticKind::MultipartSuggestion { .. } => {
                         return Ok(Some(SubdiagnosticVariant { kind, slug: None, no_span: false }));
@@ -836,7 +844,9 @@ impl SubdiagnosticVariant {
             }
             SubdiagnosticKind::Label
             | SubdiagnosticKind::Note
+            | SubdiagnosticKind::NoteOnce
             | SubdiagnosticKind::Help
+            | SubdiagnosticKind::HelpOnce
             | SubdiagnosticKind::Warn => {}
         }
 
@@ -849,7 +859,9 @@ impl quote::IdentFragment for SubdiagnosticKind {
         match self {
             SubdiagnosticKind::Label => write!(f, "label"),
             SubdiagnosticKind::Note => write!(f, "note"),
+            SubdiagnosticKind::NoteOnce => write!(f, "note_once"),
             SubdiagnosticKind::Help => write!(f, "help"),
+            SubdiagnosticKind::HelpOnce => write!(f, "help_once"),
             SubdiagnosticKind::Warn => write!(f, "warn"),
             SubdiagnosticKind::Suggestion { .. } => write!(f, "suggestions_with_style"),
             SubdiagnosticKind::MultipartSuggestion { .. } => {

compiler/rustc_macros/src/lib.rs

@@ -108,7 +108,9 @@ decl_derive!(
         // struct attributes
         diag,
         help,
+        help_once,
         note,
+        note_once,
         warning,
         // field attributes
         skip_arg,
@@ -125,7 +127,9 @@ decl_derive!(
         // struct attributes
         diag,
         help,
+        help_once,
         note,
+        note_once,
         warning,
         // field attributes
         skip_arg,
@@ -142,7 +146,9 @@ decl_derive!(
         // struct/variant attributes
         label,
         help,
+        help_once,
         note,
+        note_once,
         warning,
         subdiagnostic,
         suggestion,