]> git.proxmox.com Git - rustc.git/blobdiff - compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
New upstream version 1.65.0+dfsg1
[rustc.git] / compiler / rustc_macros / src / diagnostics / subdiagnostic.rs
index edf4dbed9853eeb8e2dbc8266ba3e92dc3012588..dce5d3cfb84ff05b87aeceb2f47148e9bb55eed1 100644 (file)
@@ -12,7 +12,7 @@ use quote::{format_ident, quote};
 use std::collections::HashMap;
 use std::fmt;
 use std::str::FromStr;
-use syn::{parse_quote, spanned::Spanned, Meta, MetaList, MetaNameValue, NestedMeta, Path};
+use syn::{spanned::Spanned, Attribute, Meta, MetaList, MetaNameValue, NestedMeta, Path};
 use synstructure::{BindingInfo, Structure, VariantInfo};
 
 /// Which kind of suggestion is being created?
@@ -28,8 +28,41 @@ enum SubdiagnosticSuggestionKind {
     Verbose,
 }
 
+impl FromStr for SubdiagnosticSuggestionKind {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "" => Ok(SubdiagnosticSuggestionKind::Normal),
+            "_short" => Ok(SubdiagnosticSuggestionKind::Short),
+            "_hidden" => Ok(SubdiagnosticSuggestionKind::Hidden),
+            "_verbose" => Ok(SubdiagnosticSuggestionKind::Verbose),
+            _ => Err(()),
+        }
+    }
+}
+
+impl SubdiagnosticSuggestionKind {
+    pub fn to_suggestion_style(&self) -> TokenStream {
+        match self {
+            SubdiagnosticSuggestionKind::Normal => {
+                quote! { rustc_errors::SuggestionStyle::ShowCode }
+            }
+            SubdiagnosticSuggestionKind::Short => {
+                quote! { rustc_errors::SuggestionStyle::HideCodeInline }
+            }
+            SubdiagnosticSuggestionKind::Hidden => {
+                quote! { rustc_errors::SuggestionStyle::HideCodeAlways }
+            }
+            SubdiagnosticSuggestionKind::Verbose => {
+                quote! { rustc_errors::SuggestionStyle::ShowAlways }
+            }
+        }
+    }
+}
+
 /// Which kind of subdiagnostic is being created from a variant?
-#[derive(Clone, Copy)]
+#[derive(Clone)]
 enum SubdiagnosticKind {
     /// `#[label(...)]`
     Label,
@@ -37,34 +70,12 @@ enum SubdiagnosticKind {
     Note,
     /// `#[help(...)]`
     Help,
-    /// `#[warn_(...)]`
+    /// `#[warning(...)]`
     Warn,
     /// `#[suggestion{,_short,_hidden,_verbose}]`
-    Suggestion(SubdiagnosticSuggestionKind),
-}
-
-impl FromStr for SubdiagnosticKind {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "label" => Ok(SubdiagnosticKind::Label),
-            "note" => Ok(SubdiagnosticKind::Note),
-            "help" => Ok(SubdiagnosticKind::Help),
-            "warn_" => Ok(SubdiagnosticKind::Warn),
-            "suggestion" => Ok(SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Normal)),
-            "suggestion_short" => {
-                Ok(SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Short))
-            }
-            "suggestion_hidden" => {
-                Ok(SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Hidden))
-            }
-            "suggestion_verbose" => {
-                Ok(SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Verbose))
-            }
-            _ => Err(()),
-        }
-    }
+    Suggestion { suggestion_kind: SubdiagnosticSuggestionKind, code: TokenStream },
+    /// `#[multipart_suggestion{,_short,_hidden,_verbose}]`
+    MultipartSuggestion { suggestion_kind: SubdiagnosticSuggestionKind },
 }
 
 impl quote::IdentFragment for SubdiagnosticKind {
@@ -74,17 +85,9 @@ impl quote::IdentFragment for SubdiagnosticKind {
             SubdiagnosticKind::Note => write!(f, "note"),
             SubdiagnosticKind::Help => write!(f, "help"),
             SubdiagnosticKind::Warn => write!(f, "warn"),
-            SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Normal) => {
-                write!(f, "suggestion")
-            }
-            SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Short) => {
-                write!(f, "suggestion_short")
-            }
-            SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Hidden) => {
-                write!(f, "suggestion_hidden")
-            }
-            SubdiagnosticKind::Suggestion(SubdiagnosticSuggestionKind::Verbose) => {
-                write!(f, "suggestion_verbose")
+            SubdiagnosticKind::Suggestion { .. } => write!(f, "suggestion_with_style"),
+            SubdiagnosticKind::MultipartSuggestion { .. } => {
+                write!(f, "multipart_suggestion_with_style")
             }
         }
     }
@@ -148,11 +151,9 @@ impl<'a> SessionSubdiagnosticDerive<'a> {
                     variant,
                     span,
                     fields: fields_map,
-                    kind: None,
-                    slug: None,
-                    code: None,
                     span_field: None,
                     applicability: None,
+                    has_suggestion_parts: false,
                 };
                 builder.into_tokens().unwrap_or_else(|v| v.to_compile_error())
             });
@@ -193,21 +194,15 @@ struct SessionSubdiagnosticDeriveBuilder<'a> {
     /// derive builder.
     fields: HashMap<String, TokenStream>,
 
-    /// Subdiagnostic kind of the type/variant.
-    kind: Option<(SubdiagnosticKind, proc_macro::Span)>,
-
-    /// Slug of the subdiagnostic - corresponds to the Fluent identifier for the message - from the
-    /// `#[kind(slug)]` attribute on the type or variant.
-    slug: Option<(Path, proc_macro::Span)>,
-    /// If a suggestion, the code to suggest as a replacement - from the `#[kind(code = "...")]`
-    /// attribute on the type or variant.
-    code: Option<(TokenStream, proc_macro::Span)>,
-
     /// Identifier for the binding to the `#[primary_span]` field.
     span_field: Option<(proc_macro2::Ident, proc_macro::Span)>,
     /// If a suggestion, the identifier for the binding to the `#[applicability]` field or a
     /// `rustc_errors::Applicability::*` variant directly.
     applicability: Option<(TokenStream, proc_macro::Span)>,
+
+    /// Set to true when a `#[suggestion_part]` field is encountered, used to generate an error
+    /// during finalization if still `false`.
+    has_suggestion_parts: bool,
 }
 
 impl<'a> HasFieldMap for SessionSubdiagnosticDeriveBuilder<'a> {
@@ -216,8 +211,40 @@ impl<'a> HasFieldMap for SessionSubdiagnosticDeriveBuilder<'a> {
     }
 }
 
+/// Provides frequently-needed information about the diagnostic kinds being derived for this type.
+#[derive(Clone, Copy, Debug)]
+struct KindsStatistics {
+    has_multipart_suggestion: bool,
+    all_multipart_suggestions: bool,
+    has_normal_suggestion: bool,
+}
+
+impl<'a> FromIterator<&'a SubdiagnosticKind> for KindsStatistics {
+    fn from_iter<T: IntoIterator<Item = &'a SubdiagnosticKind>>(kinds: T) -> Self {
+        let mut ret = Self {
+            has_multipart_suggestion: false,
+            all_multipart_suggestions: true,
+            has_normal_suggestion: false,
+        };
+        for kind in kinds {
+            if let SubdiagnosticKind::MultipartSuggestion { .. } = kind {
+                ret.has_multipart_suggestion = true;
+            } else {
+                ret.all_multipart_suggestions = false;
+            }
+
+            if let SubdiagnosticKind::Suggestion { .. } = kind {
+                ret.has_normal_suggestion = true;
+            }
+        }
+        ret
+    }
+}
+
 impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
-    fn identify_kind(&mut self) -> Result<(), DiagnosticDeriveError> {
+    fn identify_kind(&mut self) -> Result<Vec<(SubdiagnosticKind, Path)>, DiagnosticDeriveError> {
+        let mut kind_slugs = vec![];
+
         for attr in self.variant.ast().attrs {
             let span = attr.span().unwrap();
 
@@ -225,116 +252,121 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
             let name = name.as_str();
 
             let meta = attr.parse_meta()?;
-            let kind = match meta {
-                Meta::List(MetaList { ref nested, .. }) => {
-                    let mut nested_iter = nested.into_iter();
-                    if let Some(nested_attr) = nested_iter.next() {
-                        match nested_attr {
-                            NestedMeta::Meta(Meta::Path(path)) => {
-                                self.slug.set_once((path.clone(), span));
-                            }
-                            NestedMeta::Meta(meta @ Meta::NameValue(_))
-                                if matches!(
-                                    meta.path().segments.last().unwrap().ident.to_string().as_str(),
-                                    "code" | "applicability"
-                                ) =>
-                            {
-                                // don't error for valid follow-up attributes
-                            }
-                            nested_attr => {
-                                throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                                    diag.help(
-                                        "first argument of the attribute should be the diagnostic \
-                                         slug",
-                                    )
-                                })
-                            }
-                        };
-                    }
+            let Meta::List(MetaList { ref nested, .. }) = meta else {
+                throw_invalid_attr!(attr, &meta);
+            };
 
-                    for nested_attr in nested_iter {
-                        let meta = match nested_attr {
-                            NestedMeta::Meta(ref meta) => meta,
-                            _ => throw_invalid_nested_attr!(attr, &nested_attr),
-                        };
-
-                        let span = meta.span().unwrap();
-                        let nested_name = meta.path().segments.last().unwrap().ident.to_string();
-                        let nested_name = nested_name.as_str();
-
-                        match meta {
-                            Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) => {
-                                match nested_name {
-                                    "code" => {
-                                        let formatted_str = self.build_format(&s.value(), s.span());
-                                        self.code.set_once((formatted_str, span));
-                                    }
-                                    "applicability" => {
-                                        let value = match Applicability::from_str(&s.value()) {
-                                            Ok(v) => v,
-                                            Err(()) => {
-                                                span_err(span, "invalid applicability").emit();
-                                                Applicability::Unspecified
-                                            }
-                                        };
-                                        self.applicability.set_once((quote! { #value }, span));
-                                    }
-                                    _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                                        diag.help(
-                                            "only `code` and `applicability` are valid nested \
-                                             attributes",
-                                        )
-                                    }),
-                                }
-                            }
-                            _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
-                                if matches!(meta, Meta::Path(_)) {
-                                    diag.help(
-                                        "a diagnostic slug must be the first argument to the \
-                                         attribute",
-                                    )
-                                } else {
-                                    diag
-                                }
-                            }),
-                        }
+            let mut kind = match name {
+                "label" => SubdiagnosticKind::Label,
+                "note" => SubdiagnosticKind::Note,
+                "help" => SubdiagnosticKind::Help,
+                "warning" => SubdiagnosticKind::Warn,
+                _ => {
+                    if let Some(suggestion_kind) =
+                        name.strip_prefix("suggestion").and_then(|s| s.parse().ok())
+                    {
+                        SubdiagnosticKind::Suggestion { suggestion_kind, code: TokenStream::new() }
+                    } else if let Some(suggestion_kind) =
+                        name.strip_prefix("multipart_suggestion").and_then(|s| s.parse().ok())
+                    {
+                        SubdiagnosticKind::MultipartSuggestion { suggestion_kind }
+                    } else {
+                        throw_invalid_attr!(attr, &meta);
                     }
-
-                    let Ok(kind) = SubdiagnosticKind::from_str(name) else {
-                        throw_invalid_attr!(attr, &meta)
-                    };
-
-                    kind
                 }
-                _ => throw_invalid_attr!(attr, &meta),
             };
 
-            if matches!(
-                kind,
-                SubdiagnosticKind::Label | SubdiagnosticKind::Help | SubdiagnosticKind::Note
-            ) && self.code.is_some()
-            {
-                throw_span_err!(
-                    span,
-                    &format!("`code` is not a valid nested attribute of a `{}` attribute", name)
-                );
+            let mut slug = None;
+            let mut code = None;
+
+            let mut nested_iter = nested.into_iter();
+            if let Some(nested_attr) = nested_iter.next() {
+                match nested_attr {
+                    NestedMeta::Meta(Meta::Path(path)) => {
+                        slug.set_once((path.clone(), span));
+                    }
+                    NestedMeta::Meta(meta @ Meta::NameValue(_))
+                        if matches!(
+                            meta.path().segments.last().unwrap().ident.to_string().as_str(),
+                            "code" | "applicability"
+                        ) =>
+                    {
+                        // Don't error for valid follow-up attributes.
+                    }
+                    nested_attr => {
+                        throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                            diag.help(
+                                "first argument of the attribute should be the diagnostic \
+                                 slug",
+                            )
+                        })
+                    }
+                };
             }
 
-            if matches!(
-                kind,
-                SubdiagnosticKind::Label | SubdiagnosticKind::Help | SubdiagnosticKind::Note
-            ) && self.applicability.is_some()
-            {
-                throw_span_err!(
-                    span,
-                    &format!(
-                        "`applicability` is not a valid nested attribute of a `{}` attribute",
-                        name
-                    )
-                );
+            for nested_attr in nested_iter {
+                let meta = match nested_attr {
+                    NestedMeta::Meta(ref meta) => meta,
+                    _ => throw_invalid_nested_attr!(attr, &nested_attr),
+                };
+
+                let span = meta.span().unwrap();
+                let nested_name = meta.path().segments.last().unwrap().ident.to_string();
+                let nested_name = nested_name.as_str();
+
+                let value = match meta {
+                    Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(value), .. }) => value,
+                    Meta::Path(_) => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                        diag.help("a diagnostic slug must be the first argument to the attribute")
+                    }),
+                    _ => throw_invalid_nested_attr!(attr, &nested_attr),
+                };
+
+                match nested_name {
+                    "code" => {
+                        if matches!(kind, SubdiagnosticKind::Suggestion { .. }) {
+                            let formatted_str = self.build_format(&value.value(), value.span());
+                            code.set_once((formatted_str, span));
+                        } else {
+                            span_err(
+                                span,
+                                &format!(
+                                    "`code` is not a valid nested attribute of a `{}` attribute",
+                                    name
+                                ),
+                            )
+                            .emit();
+                        }
+                    }
+                    "applicability" => {
+                        if matches!(
+                            kind,
+                            SubdiagnosticKind::Suggestion { .. }
+                                | SubdiagnosticKind::MultipartSuggestion { .. }
+                        ) {
+                            let value =
+                                Applicability::from_str(&value.value()).unwrap_or_else(|()| {
+                                    span_err(span, "invalid applicability").emit();
+                                    Applicability::Unspecified
+                                });
+                            self.applicability.set_once((quote! { #value }, span));
+                        } else {
+                            span_err(
+                                span,
+                                &format!(
+                                    "`applicability` is not a valid nested attribute of a `{}` attribute",
+                                    name
+                                )
+                            ).emit();
+                        }
+                    }
+                    _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                        diag.help("only `code` and `applicability` are valid nested attributes")
+                    }),
+                }
             }
 
-            if self.slug.is_none() {
+            let Some((slug, _)) = slug else {
                 throw_span_err!(
                     span,
                     &format!(
@@ -342,150 +374,334 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
                         name
                     )
                 );
+            };
+
+            match kind {
+                SubdiagnosticKind::Suggestion { code: ref mut code_field, .. } => {
+                    let Some((code, _)) = code else {
+                        throw_span_err!(span, "suggestion without `code = \"...\"`");
+                    };
+                    *code_field = code;
+                }
+                SubdiagnosticKind::Label
+                | SubdiagnosticKind::Note
+                | SubdiagnosticKind::Help
+                | SubdiagnosticKind::Warn
+                | SubdiagnosticKind::MultipartSuggestion { .. } => {}
             }
 
-            self.kind.set_once((kind, span));
+            kind_slugs.push((kind, slug))
         }
 
-        Ok(())
+        Ok(kind_slugs)
     }
 
-    fn generate_field_code(
+    /// Generates the code for a field with no attributes.
+    fn generate_field_set_arg(&mut self, binding: &BindingInfo<'_>) -> TokenStream {
+        let ast = binding.ast();
+        assert_eq!(ast.attrs.len(), 0, "field with attribute used as diagnostic arg");
+
+        let diag = &self.diag;
+        let ident = ast.ident.as_ref().unwrap();
+        quote! {
+            #diag.set_arg(
+                stringify!(#ident),
+                #binding
+            );
+        }
+    }
+
+    /// Generates the necessary code for all attributes on a field.
+    fn generate_field_attr_code(
         &mut self,
         binding: &BindingInfo<'_>,
-        is_suggestion: bool,
-    ) -> Result<TokenStream, DiagnosticDeriveError> {
+        kind_stats: KindsStatistics,
+    ) -> TokenStream {
         let ast = binding.ast();
+        assert!(ast.attrs.len() > 0, "field without attributes generating attr code");
 
+        // Abstract over `Vec<T>` and `Option<T>` fields using `FieldInnerTy`, which will
+        // apply the generated code on each element in the `Vec` or `Option`.
         let inner_ty = FieldInnerTy::from_type(&ast.ty);
-        let info = FieldInfo {
-            binding: binding,
-            ty: inner_ty.inner_type().unwrap_or(&ast.ty),
-            span: &ast.span(),
-        };
+        ast.attrs
+            .iter()
+            .map(|attr| {
+                let info = FieldInfo {
+                    binding,
+                    ty: inner_ty.inner_type().unwrap_or(&ast.ty),
+                    span: &ast.span(),
+                };
 
-        for attr in &ast.attrs {
-            let name = attr.path.segments.last().unwrap().ident.to_string();
-            let name = name.as_str();
-            let span = attr.span().unwrap();
+                let generated = self
+                    .generate_field_code_inner(kind_stats, attr, info)
+                    .unwrap_or_else(|v| v.to_compile_error());
 
-            let meta = attr.parse_meta()?;
-            match meta {
-                Meta::Path(_) => match name {
-                    "primary_span" => {
-                        report_error_if_not_applied_to_span(attr, &info)?;
-                        self.span_field.set_once((binding.binding.clone(), span));
-                        return Ok(quote! {});
-                    }
-                    "applicability" if is_suggestion => {
-                        report_error_if_not_applied_to_applicability(attr, &info)?;
-                        let binding = binding.binding.clone();
-                        self.applicability.set_once((quote! { #binding }, span));
-                        return Ok(quote! {});
-                    }
-                    "applicability" => {
-                        span_err(span, "`#[applicability]` is only valid on suggestions").emit();
-                        return Ok(quote! {});
-                    }
-                    "skip_arg" => {
-                        return Ok(quote! {});
-                    }
-                    _ => throw_invalid_attr!(attr, &meta, |diag| {
+                inner_ty.with(binding, generated)
+            })
+            .collect()
+    }
+
+    fn generate_field_code_inner(
+        &mut self,
+        kind_stats: KindsStatistics,
+        attr: &Attribute,
+        info: FieldInfo<'_>,
+    ) -> Result<TokenStream, DiagnosticDeriveError> {
+        let meta = attr.parse_meta()?;
+        match meta {
+            Meta::Path(path) => self.generate_field_code_inner_path(kind_stats, attr, info, path),
+            Meta::List(list @ MetaList { .. }) => {
+                self.generate_field_code_inner_list(kind_stats, attr, info, list)
+            }
+            _ => throw_invalid_attr!(attr, &meta),
+        }
+    }
+
+    /// Generates the code for a `[Meta::Path]`-like attribute on a field (e.g. `#[primary_span]`).
+    fn generate_field_code_inner_path(
+        &mut self,
+        kind_stats: KindsStatistics,
+        attr: &Attribute,
+        info: FieldInfo<'_>,
+        path: Path,
+    ) -> Result<TokenStream, DiagnosticDeriveError> {
+        let span = attr.span().unwrap();
+        let ident = &path.segments.last().unwrap().ident;
+        let name = ident.to_string();
+        let name = name.as_str();
+
+        match name {
+            "skip_arg" => Ok(quote! {}),
+            "primary_span" => {
+                if kind_stats.has_multipart_suggestion {
+                    throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
                         diag.help(
-                            "only `primary_span`, `applicability` and `skip_arg` are valid field \
-                             attributes",
+                            "multipart suggestions use one or more `#[suggestion_part]`s rather \
+                            than one `#[primary_span]`",
                         )
-                    }),
-                },
-                _ => throw_invalid_attr!(attr, &meta),
+                    })
+                }
+
+                report_error_if_not_applied_to_span(attr, &info)?;
+
+                let binding = info.binding.binding.clone();
+                self.span_field.set_once((binding, span));
+
+                Ok(quote! {})
+            }
+            "suggestion_part" => {
+                self.has_suggestion_parts = true;
+
+                if kind_stats.has_multipart_suggestion {
+                    span_err(span, "`#[suggestion_part(...)]` attribute without `code = \"...\"`")
+                        .emit();
+                    Ok(quote! {})
+                } else {
+                    throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
+                        diag.help(
+                                "`#[suggestion_part(...)]` is only valid in multipart suggestions, use `#[primary_span]` instead",
+                            )
+                    });
+                }
+            }
+            "applicability" => {
+                if kind_stats.has_multipart_suggestion || kind_stats.has_normal_suggestion {
+                    report_error_if_not_applied_to_applicability(attr, &info)?;
+
+                    let binding = info.binding.binding.clone();
+                    self.applicability.set_once((quote! { #binding }, span));
+                } else {
+                    span_err(span, "`#[applicability]` is only valid on suggestions").emit();
+                }
+
+                Ok(quote! {})
             }
+            _ => throw_invalid_attr!(attr, &Meta::Path(path), |diag| {
+                let mut span_attrs = vec![];
+                if kind_stats.has_multipart_suggestion {
+                    span_attrs.push("suggestion_part");
+                }
+                if !kind_stats.all_multipart_suggestions {
+                    span_attrs.push("primary_span")
+                }
+                diag.help(format!(
+                    "only `{}`, `applicability` and `skip_arg` are valid field attributes",
+                    span_attrs.join(", ")
+                ))
+            }),
         }
+    }
 
-        let ident = ast.ident.as_ref().unwrap();
+    /// Generates the code for a `[Meta::List]`-like attribute on a field (e.g.
+    /// `#[suggestion_part(code = "...")]`).
+    fn generate_field_code_inner_list(
+        &mut self,
+        kind_stats: KindsStatistics,
+        attr: &Attribute,
+        info: FieldInfo<'_>,
+        list: MetaList,
+    ) -> Result<TokenStream, DiagnosticDeriveError> {
+        let span = attr.span().unwrap();
+        let ident = &list.path.segments.last().unwrap().ident;
+        let name = ident.to_string();
+        let name = name.as_str();
+
+        match name {
+            "suggestion_part" => {
+                if !kind_stats.has_multipart_suggestion {
+                    throw_invalid_attr!(attr, &Meta::List(list), |diag| {
+                        diag.help(
+                            "`#[suggestion_part(...)]` is only valid in multipart suggestions",
+                        )
+                    })
+                }
 
-        let diag = &self.diag;
-        let generated = quote! {
-            #diag.set_arg(
-                stringify!(#ident),
-                #binding
-            );
-        };
+                self.has_suggestion_parts = true;
+
+                report_error_if_not_applied_to_span(attr, &info)?;
+
+                let mut code = None;
+                for nested_attr in list.nested.iter() {
+                    let NestedMeta::Meta(ref meta) = nested_attr else {
+                        throw_invalid_nested_attr!(attr, &nested_attr);
+                    };
+
+                    let span = meta.span().unwrap();
+                    let nested_name = meta.path().segments.last().unwrap().ident.to_string();
+                    let nested_name = nested_name.as_str();
+
+                    let Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(value), .. }) = meta else {
+                        throw_invalid_nested_attr!(attr, &nested_attr);
+                    };
+
+                    match nested_name {
+                        "code" => {
+                            let formatted_str = self.build_format(&value.value(), value.span());
+                            code.set_once((formatted_str, span));
+                        }
+                        _ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
+                            diag.help("`code` is the only valid nested attribute")
+                        }),
+                    }
+                }
 
-        Ok(inner_ty.with(binding, generated))
+                let Some((code, _)) = code else {
+                    span_err(span, "`#[suggestion_part(...)]` attribute without `code = \"...\"`")
+                        .emit();
+                    return Ok(quote! {});
+                };
+                let binding = info.binding;
+
+                Ok(quote! { suggestions.push((#binding, #code)); })
+            }
+            _ => throw_invalid_attr!(attr, &Meta::List(list), |diag| {
+                let mut span_attrs = vec![];
+                if kind_stats.has_multipart_suggestion {
+                    span_attrs.push("suggestion_part");
+                }
+                if !kind_stats.all_multipart_suggestions {
+                    span_attrs.push("primary_span")
+                }
+                diag.help(format!(
+                    "only `{}`, `applicability` and `skip_arg` are valid field attributes",
+                    span_attrs.join(", ")
+                ))
+            }),
+        }
     }
 
-    fn into_tokens(&mut self) -> Result<TokenStream, DiagnosticDeriveError> {
-        self.identify_kind()?;
-        let Some(kind) = self.kind.map(|(kind, _)| kind) else {
+    pub fn into_tokens(&mut self) -> Result<TokenStream, DiagnosticDeriveError> {
+        let kind_slugs = self.identify_kind()?;
+        if kind_slugs.is_empty() {
             throw_span_err!(
                 self.variant.ast().ident.span().unwrap(),
                 "subdiagnostic kind not specified"
             );
         };
 
-        let is_suggestion = matches!(kind, SubdiagnosticKind::Suggestion(_));
+        let kind_stats: KindsStatistics = kind_slugs.iter().map(|(kind, _slug)| kind).collect();
 
-        let mut args = TokenStream::new();
-        for binding in self.variant.bindings() {
-            let arg = self
-                .generate_field_code(binding, is_suggestion)
-                .unwrap_or_else(|v| v.to_compile_error());
-            args.extend(arg);
-        }
-
-        // Missing slug errors will already have been reported.
-        let slug = self
-            .slug
-            .as_ref()
-            .map(|(slug, _)| slug.clone())
-            .unwrap_or_else(|| parse_quote! { you::need::to::specify::a::slug });
-        let code = match self.code.as_ref() {
-            Some((code, _)) => Some(quote! { #code }),
-            None if is_suggestion => {
-                span_err(self.span, "suggestion without `code = \"...\"`").emit();
-                Some(quote! { /* macro error */ "..." })
-            }
-            None => None,
+        let init = if kind_stats.has_multipart_suggestion {
+            quote! { let mut suggestions = Vec::new(); }
+        } else {
+            quote! {}
         };
 
+        let attr_args: TokenStream = self
+            .variant
+            .bindings()
+            .iter()
+            .filter(|binding| !binding.ast().attrs.is_empty())
+            .map(|binding| self.generate_field_attr_code(binding, kind_stats))
+            .collect();
+
         let span_field = self.span_field.as_ref().map(|(span, _)| span);
-        let applicability = match self.applicability.clone() {
-            Some((applicability, _)) => Some(applicability),
-            None if is_suggestion => {
-                span_err(self.span, "suggestion without `applicability`").emit();
-                Some(quote! { rustc_errors::Applicability::Unspecified })
-            }
-            None => None,
-        };
+        let applicability = self.applicability.take().map_or_else(
+            || quote! { rustc_errors::Applicability::Unspecified },
+            |(applicability, _)| applicability,
+        );
 
         let diag = &self.diag;
-        let name = format_ident!("{}{}", if span_field.is_some() { "span_" } else { "" }, kind);
-        let message = quote! { rustc_errors::fluent::#slug };
-        let call = if matches!(kind, SubdiagnosticKind::Suggestion(..)) {
-            if let Some(span) = span_field {
-                quote! { #diag.#name(#span, #message, #code, #applicability); }
-            } else {
-                span_err(self.span, "suggestion without `#[primary_span]` field").emit();
-                quote! { unreachable!(); }
-            }
-        } else if matches!(kind, SubdiagnosticKind::Label) {
-            if let Some(span) = span_field {
-                quote! { #diag.#name(#span, #message); }
-            } else {
-                span_err(self.span, "label without `#[primary_span]` field").emit();
-                quote! { unreachable!(); }
-            }
-        } else {
-            if let Some(span) = span_field {
-                quote! { #diag.#name(#span, #message); }
-            } else {
-                quote! { #diag.#name(#message); }
-            }
-        };
+        let mut calls = TokenStream::new();
+        for (kind, slug) in kind_slugs {
+            let name = format_ident!("{}{}", if span_field.is_some() { "span_" } else { "" }, kind);
+            let message = quote! { rustc_errors::fluent::#slug };
+            let call = match kind {
+                SubdiagnosticKind::Suggestion { suggestion_kind, code } => {
+                    if let Some(span) = span_field {
+                        let style = suggestion_kind.to_suggestion_style();
+
+                        quote! { #diag.#name(#span, #message, #code, #applicability, #style); }
+                    } else {
+                        span_err(self.span, "suggestion without `#[primary_span]` field").emit();
+                        quote! { unreachable!(); }
+                    }
+                }
+                SubdiagnosticKind::MultipartSuggestion { suggestion_kind } => {
+                    if !self.has_suggestion_parts {
+                        span_err(
+                            self.span,
+                            "multipart suggestion without any `#[suggestion_part(...)]` fields",
+                        )
+                        .emit();
+                    }
+
+                    let style = suggestion_kind.to_suggestion_style();
+
+                    quote! { #diag.#name(#message, suggestions, #applicability, #style); }
+                }
+                SubdiagnosticKind::Label => {
+                    if let Some(span) = span_field {
+                        quote! { #diag.#name(#span, #message); }
+                    } else {
+                        span_err(self.span, "label without `#[primary_span]` field").emit();
+                        quote! { unreachable!(); }
+                    }
+                }
+                _ => {
+                    if let Some(span) = span_field {
+                        quote! { #diag.#name(#span, #message); }
+                    } else {
+                        quote! { #diag.#name(#message); }
+                    }
+                }
+            };
+            calls.extend(call);
+        }
+
+        let plain_args: TokenStream = self
+            .variant
+            .bindings()
+            .iter()
+            .filter(|binding| binding.ast().attrs.is_empty())
+            .map(|binding| self.generate_field_set_arg(binding))
+            .collect();
 
         Ok(quote! {
-            #call
-            #args
+            #init
+            #attr_args
+            #calls
+            #plain_args
         })
     }
 }