| #![deny(unused_must_use)] |
| |
| use crate::diagnostics::error::{ |
| span_err, throw_invalid_attr, throw_span_err, DiagnosticDeriveError, |
| }; |
| use crate::diagnostics::utils::{ |
| build_field_mapping, is_doc_comment, report_error_if_not_applied_to_span, report_type_error, |
| should_generate_set_arg, type_is_bool, type_is_unit, type_matches_path, FieldInfo, |
| FieldInnerTy, FieldMap, HasFieldMap, SetOnce, SpannedOption, SubdiagnosticKind, |
| }; |
| use proc_macro2::{Ident, Span, TokenStream}; |
| use quote::{format_ident, quote, quote_spanned}; |
| use syn::Token; |
| use syn::{parse_quote, spanned::Spanned, Attribute, Meta, Path, Type}; |
| use synstructure::{BindingInfo, Structure, VariantInfo}; |
| |
| /// What kind of diagnostic is being derived - a fatal/error/warning or a lint? |
| #[derive(Clone, PartialEq, Eq)] |
| pub(crate) enum DiagnosticDeriveKind { |
| Diagnostic { handler: syn::Ident }, |
| LintDiagnostic, |
| } |
| |
| /// Tracks persistent information required for the entire type when building up individual calls to |
| /// diagnostic methods for generated diagnostic derives - both `Diagnostic` for |
| /// fatal/errors/warnings and `LintDiagnostic` for lints. |
| pub(crate) struct DiagnosticDeriveBuilder { |
| /// The identifier to use for the generated `DiagnosticBuilder` instance. |
| pub diag: syn::Ident, |
| /// Kind of diagnostic that should be derived. |
| pub kind: DiagnosticDeriveKind, |
| } |
| |
| /// Tracks persistent information required for a specific variant when building up individual calls |
| /// to diagnostic methods for generated diagnostic derives - both `Diagnostic` for |
| /// fatal/errors/warnings and `LintDiagnostic` for lints. |
| pub(crate) struct DiagnosticDeriveVariantBuilder<'parent> { |
| /// The parent builder for the entire type. |
| pub parent: &'parent DiagnosticDeriveBuilder, |
| |
| /// Initialization of format strings for code suggestions. |
| pub formatting_init: TokenStream, |
| |
| /// Span of the struct or the enum variant. |
| pub span: proc_macro::Span, |
| |
| /// Store a map of field name to its corresponding field. This is built on construction of the |
| /// derive builder. |
| pub field_map: FieldMap, |
| |
| /// Slug is a mandatory part of the struct attribute as corresponds to the Fluent message that |
| /// has the actual diagnostic message. |
| pub slug: SpannedOption<Path>, |
| /// Error codes are a optional part of the struct attribute - this is only set to detect |
| /// multiple specifications. |
| pub code: SpannedOption<()>, |
| } |
| |
| impl<'a> HasFieldMap for DiagnosticDeriveVariantBuilder<'a> { |
| fn get_field_binding(&self, field: &String) -> Option<&TokenStream> { |
| self.field_map.get(field) |
| } |
| } |
| |
| impl DiagnosticDeriveBuilder { |
| /// Call `f` for the struct or for each variant of the enum, returning a `TokenStream` with the |
| /// tokens from `f` wrapped in an `match` expression. Emits errors for use of derive on unions |
| /// or attributes on the type itself when input is an enum. |
| pub fn each_variant<'s, F>(&mut self, structure: &mut Structure<'s>, f: F) -> TokenStream |
| where |
| F: for<'a, 'v> Fn(DiagnosticDeriveVariantBuilder<'a>, &VariantInfo<'v>) -> TokenStream, |
| { |
| let ast = structure.ast(); |
| let span = ast.span().unwrap(); |
| match ast.data { |
| syn::Data::Struct(..) | syn::Data::Enum(..) => (), |
| syn::Data::Union(..) => { |
| span_err(span, "diagnostic derives can only be used on structs and enums").emit(); |
| } |
| } |
| |
| if matches!(ast.data, syn::Data::Enum(..)) { |
| for attr in &ast.attrs { |
| span_err( |
| attr.span().unwrap(), |
| "unsupported type attribute for diagnostic derive enum", |
| ) |
| .emit(); |
| } |
| } |
| |
| structure.bind_with(|_| synstructure::BindStyle::Move); |
| let variants = structure.each_variant(|variant| { |
| let span = match structure.ast().data { |
| syn::Data::Struct(..) => span, |
| // There isn't a good way to get the span of the variant, so the variant's |
| // name will need to do. |
| _ => variant.ast().ident.span().unwrap(), |
| }; |
| let builder = DiagnosticDeriveVariantBuilder { |
| parent: self, |
| span, |
| field_map: build_field_mapping(variant), |
| formatting_init: TokenStream::new(), |
| slug: None, |
| code: None, |
| }; |
| f(builder, variant) |
| }); |
| |
| quote! { |
| match self { |
| #variants |
| } |
| } |
| } |
| } |
| |
| impl<'a> DiagnosticDeriveVariantBuilder<'a> { |
| /// Generates calls to `code` and similar functions based on the attributes on the type or |
| /// variant. |
| pub fn preamble(&mut self, variant: &VariantInfo<'_>) -> TokenStream { |
| let ast = variant.ast(); |
| let attrs = &ast.attrs; |
| let preamble = attrs.iter().map(|attr| { |
| self.generate_structure_code_for_attr(attr).unwrap_or_else(|v| v.to_compile_error()) |
| }); |
| |
| quote! { |
| #(#preamble)*; |
| } |
| } |
| |
| /// Generates calls to `span_label` and similar functions based on the attributes on fields or |
| /// calls to `set_arg` when no attributes are present. |
| pub fn body(&mut self, variant: &VariantInfo<'_>) -> TokenStream { |
| let mut body = quote! {}; |
| // Generate `set_arg` calls first.. |
| for binding in variant.bindings().iter().filter(|bi| should_generate_set_arg(bi.ast())) { |
| body.extend(self.generate_field_code(binding)); |
| } |
| // ..and then subdiagnostic additions. |
| for binding in variant.bindings().iter().filter(|bi| !should_generate_set_arg(bi.ast())) { |
| body.extend(self.generate_field_attrs_code(binding)); |
| } |
| body |
| } |
| |
| /// Parse a `SubdiagnosticKind` from an `Attribute`. |
| fn parse_subdiag_attribute( |
| &self, |
| attr: &Attribute, |
| ) -> Result<Option<(SubdiagnosticKind, Path)>, DiagnosticDeriveError> { |
| let Some((subdiag, slug)) = SubdiagnosticKind::from_attr(attr, self)? else { |
| // Some attributes aren't errors - like documentation comments - but also aren't |
| // subdiagnostics. |
| return Ok(None); |
| }; |
| |
| if let SubdiagnosticKind::MultipartSuggestion { .. } = subdiag { |
| throw_invalid_attr!(attr, |diag| diag |
| .help("consider creating a `Subdiagnostic` instead")); |
| } |
| |
| let slug = slug.unwrap_or_else(|| match subdiag { |
| SubdiagnosticKind::Label => parse_quote! { _subdiag::label }, |
| SubdiagnosticKind::Note => parse_quote! { _subdiag::note }, |
| SubdiagnosticKind::Help => parse_quote! { _subdiag::help }, |
| SubdiagnosticKind::Warn => parse_quote! { _subdiag::warn }, |
| SubdiagnosticKind::Suggestion { .. } => parse_quote! { _subdiag::suggestion }, |
| SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(), |
| }); |
| |
| Ok(Some((subdiag, slug))) |
| } |
| |
| /// Establishes state in the `DiagnosticDeriveBuilder` resulting from the struct |
| /// attributes like `#[diag(..)]`, such as the slug and error code. Generates |
| /// diagnostic builder calls for setting error code and creating note/help messages. |
| fn generate_structure_code_for_attr( |
| &mut self, |
| attr: &Attribute, |
| ) -> Result<TokenStream, DiagnosticDeriveError> { |
| let diag = &self.parent.diag; |
| |
| // Always allow documentation comments. |
| if is_doc_comment(attr) { |
| return Ok(quote! {}); |
| } |
| |
| let name = attr.path().segments.last().unwrap().ident.to_string(); |
| let name = name.as_str(); |
| |
| let mut first = true; |
| |
| if name == "diag" { |
| let mut tokens = TokenStream::new(); |
| attr.parse_nested_meta(|nested| { |
| let path = &nested.path; |
| |
| if first && (nested.input.is_empty() || nested.input.peek(Token![,])) { |
| self.slug.set_once(path.clone(), path.span().unwrap()); |
| first = false; |
| return Ok(()) |
| } |
| |
| first = false; |
| |
| let Ok(nested) = nested.value() else { |
| span_err(nested.input.span().unwrap(), "diagnostic slug must be the first argument").emit(); |
| return Ok(()) |
| }; |
| |
| if path.is_ident("code") { |
| self.code.set_once((), path.span().unwrap()); |
| |
| let code = nested.parse::<syn::LitStr>()?; |
| tokens.extend(quote! { |
| #diag.code(rustc_errors::DiagnosticId::Error(#code.to_string())); |
| }); |
| } else { |
| span_err(path.span().unwrap(), "unknown argument").note("only the `code` parameter is valid after the slug").emit(); |
| |
| // consume the buffer so we don't have syntax errors from syn |
| let _ = nested.parse::<TokenStream>(); |
| } |
| Ok(()) |
| })?; |
| return Ok(tokens); |
| } |
| |
| let Some((subdiag, slug)) = self.parse_subdiag_attribute(attr)? else { |
| // Some attributes aren't errors - like documentation comments - but also aren't |
| // subdiagnostics. |
| return Ok(quote! {}); |
| }; |
| let fn_ident = format_ident!("{}", subdiag); |
| match subdiag { |
| SubdiagnosticKind::Note | SubdiagnosticKind::Help | 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")); |
| } |
| SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(), |
| } |
| } |
| |
| fn generate_field_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream { |
| let diag = &self.parent.diag; |
| |
| let field = binding_info.ast(); |
| let mut field_binding = binding_info.binding.clone(); |
| field_binding.set_span(field.ty.span()); |
| |
| let ident = field.ident.as_ref().unwrap(); |
| let ident = format_ident!("{}", ident); // strip `r#` prefix, if present |
| |
| quote! { |
| #diag.set_arg( |
| stringify!(#ident), |
| #field_binding |
| ); |
| } |
| } |
| |
| fn generate_field_attrs_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream { |
| let field = binding_info.ast(); |
| let field_binding = &binding_info.binding; |
| |
| let inner_ty = FieldInnerTy::from_type(&field.ty); |
| |
| field |
| .attrs |
| .iter() |
| .map(move |attr| { |
| // Always allow documentation comments. |
| if is_doc_comment(attr) { |
| return quote! {}; |
| } |
| |
| let name = attr.path().segments.last().unwrap().ident.to_string(); |
| let needs_clone = |
| name == "primary_span" && matches!(inner_ty, FieldInnerTy::Vec(_)); |
| let (binding, needs_destructure) = if needs_clone { |
| // `primary_span` can accept a `Vec<Span>` so don't destructure that. |
| (quote_spanned! {inner_ty.span()=> #field_binding.clone() }, false) |
| } else { |
| (quote_spanned! {inner_ty.span()=> #field_binding }, true) |
| }; |
| |
| let generated_code = self |
| .generate_inner_field_code( |
| attr, |
| FieldInfo { binding: binding_info, ty: inner_ty, span: &field.span() }, |
| binding, |
| ) |
| .unwrap_or_else(|v| v.to_compile_error()); |
| |
| if needs_destructure { |
| inner_ty.with(field_binding, generated_code) |
| } else { |
| generated_code |
| } |
| }) |
| .collect() |
| } |
| |
| fn generate_inner_field_code( |
| &mut self, |
| attr: &Attribute, |
| info: FieldInfo<'_>, |
| binding: TokenStream, |
| ) -> Result<TokenStream, DiagnosticDeriveError> { |
| let diag = &self.parent.diag; |
| |
| let ident = &attr.path().segments.last().unwrap().ident; |
| let name = ident.to_string(); |
| match (&attr.meta, name.as_str()) { |
| // Don't need to do anything - by virtue of the attribute existing, the |
| // `set_arg` call will not be generated. |
| (Meta::Path(_), "skip_arg") => return Ok(quote! {}), |
| (Meta::Path(_), "primary_span") => { |
| match self.parent.kind { |
| DiagnosticDeriveKind::Diagnostic { .. } => { |
| report_error_if_not_applied_to_span(attr, &info)?; |
| |
| return Ok(quote! { |
| #diag.set_span(#binding); |
| }); |
| } |
| DiagnosticDeriveKind::LintDiagnostic => { |
| throw_invalid_attr!(attr, |diag| { |
| diag.help("the `primary_span` field attribute is not valid for lint diagnostics") |
| }) |
| } |
| } |
| } |
| (Meta::Path(_), "subdiagnostic") => { |
| if FieldInnerTy::from_type(&info.binding.ast().ty).will_iterate() { |
| let DiagnosticDeriveKind::Diagnostic { handler } = &self.parent.kind else { |
| // No eager translation for lints. |
| return Ok(quote! { #diag.subdiagnostic(#binding); }); |
| }; |
| return Ok(quote! { #diag.eager_subdiagnostic(#handler, #binding); }); |
| } else { |
| return Ok(quote! { #diag.subdiagnostic(#binding); }); |
| } |
| } |
| (Meta::List(meta_list), "subdiagnostic") => { |
| let err = || { |
| span_err( |
| meta_list.span().unwrap(), |
| "`eager` is the only supported nested attribute for `subdiagnostic`", |
| ) |
| .emit(); |
| }; |
| |
| let Ok(p): Result<Path, _> = meta_list.parse_args() else { |
| err(); |
| return Ok(quote! {}); |
| }; |
| |
| if !p.is_ident("eager") { |
| err(); |
| return Ok(quote! {}); |
| } |
| |
| let handler = match &self.parent.kind { |
| DiagnosticDeriveKind::Diagnostic { handler } => handler, |
| DiagnosticDeriveKind::LintDiagnostic => { |
| throw_invalid_attr!(attr, |diag| { |
| diag.help("eager subdiagnostics are not supported on lints") |
| }) |
| } |
| }; |
| return Ok(quote! { #diag.eager_subdiagnostic(#handler, #binding); }); |
| } |
| _ => (), |
| } |
| |
| let Some((subdiag, slug)) = self.parse_subdiag_attribute(attr)? else { |
| // Some attributes aren't errors - like documentation comments - but also aren't |
| // subdiagnostics. |
| return Ok(quote! {}); |
| }; |
| let fn_ident = format_ident!("{}", subdiag); |
| match subdiag { |
| SubdiagnosticKind::Label => { |
| report_error_if_not_applied_to_span(attr, &info)?; |
| Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug)) |
| } |
| SubdiagnosticKind::Note | SubdiagnosticKind::Help | SubdiagnosticKind::Warn => { |
| let inner = info.ty.inner_type(); |
| if type_matches_path(inner, &["rustc_span", "Span"]) |
| || type_matches_path(inner, &["rustc_span", "MultiSpan"]) |
| { |
| Ok(self.add_spanned_subdiagnostic(binding, &fn_ident, slug)) |
| } else if type_is_unit(inner) |
| || (matches!(info.ty, FieldInnerTy::Plain(_)) && type_is_bool(inner)) |
| { |
| Ok(self.add_subdiagnostic(&fn_ident, slug)) |
| } else { |
| report_type_error(attr, "`Span`, `MultiSpan`, `bool` or `()`")? |
| } |
| } |
| SubdiagnosticKind::Suggestion { |
| suggestion_kind, |
| applicability: static_applicability, |
| code_field, |
| code_init, |
| } => { |
| if let FieldInnerTy::Vec(_) = info.ty { |
| throw_invalid_attr!(attr, |diag| { |
| diag |
| .note("`#[suggestion(...)]` applied to `Vec` field is ambiguous") |
| .help("to show a suggestion consisting of multiple parts, use a `Subdiagnostic` annotated with `#[multipart_suggestion(...)]`") |
| .help("to show a variable set of suggestions, use a `Vec` of `Subdiagnostic`s annotated with `#[suggestion(...)]`") |
| }); |
| } |
| |
| let (span_field, mut applicability) = self.span_and_applicability_of_ty(info)?; |
| |
| if let Some((static_applicability, span)) = static_applicability { |
| applicability.set_once(quote! { #static_applicability }, span); |
| } |
| |
| let applicability = applicability |
| .value() |
| .unwrap_or_else(|| quote! { rustc_errors::Applicability::Unspecified }); |
| let style = suggestion_kind.to_suggestion_style(); |
| |
| self.formatting_init.extend(code_init); |
| Ok(quote! { |
| #diag.span_suggestions_with_style( |
| #span_field, |
| crate::fluent_generated::#slug, |
| #code_field, |
| #applicability, |
| #style |
| ); |
| }) |
| } |
| SubdiagnosticKind::MultipartSuggestion { .. } => unreachable!(), |
| } |
| } |
| |
| /// Adds a spanned subdiagnostic by generating a `diag.span_$kind` call with the current slug |
| /// and `fluent_attr_identifier`. |
| fn add_spanned_subdiagnostic( |
| &self, |
| field_binding: TokenStream, |
| kind: &Ident, |
| fluent_attr_identifier: Path, |
| ) -> TokenStream { |
| let diag = &self.parent.diag; |
| let fn_name = format_ident!("span_{}", kind); |
| quote! { |
| #diag.#fn_name( |
| #field_binding, |
| crate::fluent_generated::#fluent_attr_identifier |
| ); |
| } |
| } |
| |
| /// Adds a subdiagnostic by generating a `diag.span_$kind` call with the current slug |
| /// and `fluent_attr_identifier`. |
| fn add_subdiagnostic(&self, kind: &Ident, fluent_attr_identifier: Path) -> TokenStream { |
| let diag = &self.parent.diag; |
| quote! { |
| #diag.#kind(crate::fluent_generated::#fluent_attr_identifier); |
| } |
| } |
| |
| fn span_and_applicability_of_ty( |
| &self, |
| info: FieldInfo<'_>, |
| ) -> Result<(TokenStream, SpannedOption<TokenStream>), DiagnosticDeriveError> { |
| match &info.ty.inner_type() { |
| // If `ty` is `Span` w/out applicability, then use `Applicability::Unspecified`. |
| ty @ Type::Path(..) if type_matches_path(ty, &["rustc_span", "Span"]) => { |
| let binding = &info.binding.binding; |
| Ok((quote!(#binding), None)) |
| } |
| // If `ty` is `(Span, Applicability)` then return tokens accessing those. |
| Type::Tuple(tup) => { |
| let mut span_idx = None; |
| let mut applicability_idx = None; |
| |
| fn type_err(span: &Span) -> Result<!, DiagnosticDeriveError> { |
| span_err(span.unwrap(), "wrong types for suggestion") |
| .help( |
| "`#[suggestion(...)]` on a tuple field must be applied to fields \ |
| of type `(Span, Applicability)`", |
| ) |
| .emit(); |
| Err(DiagnosticDeriveError::ErrorHandled) |
| } |
| |
| for (idx, elem) in tup.elems.iter().enumerate() { |
| if type_matches_path(elem, &["rustc_span", "Span"]) { |
| span_idx.set_once(syn::Index::from(idx), elem.span().unwrap()); |
| } else if type_matches_path(elem, &["rustc_errors", "Applicability"]) { |
| applicability_idx.set_once(syn::Index::from(idx), elem.span().unwrap()); |
| } else { |
| type_err(&elem.span())?; |
| } |
| } |
| |
| let Some((span_idx, _)) = span_idx else { |
| type_err(&tup.span())?; |
| }; |
| let Some((applicability_idx, applicability_span)) = applicability_idx else { |
| type_err(&tup.span())?; |
| }; |
| let binding = &info.binding.binding; |
| let span = quote!(#binding.#span_idx); |
| let applicability = quote!(#binding.#applicability_idx); |
| |
| Ok((span, Some((applicability, applicability_span)))) |
| } |
| // If `ty` isn't a `Span` or `(Span, Applicability)` then emit an error. |
| _ => throw_span_err!(info.span.unwrap(), "wrong field type for suggestion", |diag| { |
| diag.help( |
| "`#[suggestion(...)]` should be applied to fields of type `Span` or \ |
| `(Span, Applicability)`", |
| ) |
| }), |
| } |
| } |
| } |
