126 lines
4.4 KiB
Rust
126 lines
4.4 KiB
Rust
//! Detecting diagnostic items.
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//!
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//! Diagnostic items are items that are not language-inherent, but can reasonably be expected to
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//! exist for diagnostic purposes. This allows diagnostic authors to refer to specific items
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//! directly, without having to guess module paths and crates.
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//! Examples are:
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//!
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//! * Traits like `Debug`, that have no bearing on language semantics
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//!
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//! * Compiler internal types like `Ty` and `TyCtxt`
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use rustc_ast as ast;
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use rustc_hir as hir;
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use rustc_hir::diagnostic_items::DiagnosticItems;
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use rustc_hir::itemlikevisit::ItemLikeVisitor;
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use rustc_middle::ty::query::Providers;
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use rustc_middle::ty::TyCtxt;
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use rustc_span::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
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use rustc_span::symbol::{sym, Symbol};
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struct DiagnosticItemCollector<'tcx> {
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tcx: TyCtxt<'tcx>,
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diagnostic_items: DiagnosticItems,
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}
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impl<'v, 'tcx> ItemLikeVisitor<'v> for DiagnosticItemCollector<'tcx> {
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fn visit_item(&mut self, item: &hir::Item<'_>) {
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self.observe_item(item.def_id);
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}
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fn visit_trait_item(&mut self, trait_item: &hir::TraitItem<'_>) {
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self.observe_item(trait_item.def_id);
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}
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fn visit_impl_item(&mut self, impl_item: &hir::ImplItem<'_>) {
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self.observe_item(impl_item.def_id);
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}
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fn visit_foreign_item(&mut self, foreign_item: &hir::ForeignItem<'_>) {
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self.observe_item(foreign_item.def_id);
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}
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}
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impl<'tcx> DiagnosticItemCollector<'tcx> {
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fn new(tcx: TyCtxt<'tcx>) -> DiagnosticItemCollector<'tcx> {
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DiagnosticItemCollector { tcx, diagnostic_items: DiagnosticItems::default() }
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}
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fn observe_item(&mut self, def_id: LocalDefId) {
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let hir_id = self.tcx.hir().local_def_id_to_hir_id(def_id);
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let attrs = self.tcx.hir().attrs(hir_id);
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if let Some(name) = extract(attrs) {
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// insert into our table
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collect_item(self.tcx, &mut self.diagnostic_items, name, def_id.to_def_id());
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}
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}
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}
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fn collect_item(tcx: TyCtxt<'_>, items: &mut DiagnosticItems, name: Symbol, item_def_id: DefId) {
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items.id_to_name.insert(item_def_id, name);
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if let Some(original_def_id) = items.name_to_id.insert(name, item_def_id) {
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if original_def_id != item_def_id {
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let mut err = match tcx.hir().span_if_local(item_def_id) {
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Some(span) => tcx.sess.struct_span_err(
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span,
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&format!("duplicate diagnostic item found: `{}`.", name),
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),
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None => tcx.sess.struct_err(&format!(
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"duplicate diagnostic item in crate `{}`: `{}`.",
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tcx.crate_name(item_def_id.krate),
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name
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)),
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};
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if let Some(span) = tcx.hir().span_if_local(original_def_id) {
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err.span_note(span, "the diagnostic item is first defined here");
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} else {
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err.note(&format!(
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"the diagnostic item is first defined in crate `{}`.",
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tcx.crate_name(original_def_id.krate)
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));
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}
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err.emit();
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}
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}
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}
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/// Extract the first `rustc_diagnostic_item = "$name"` out of a list of attributes.p
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fn extract(attrs: &[ast::Attribute]) -> Option<Symbol> {
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attrs.iter().find_map(|attr| {
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if attr.has_name(sym::rustc_diagnostic_item) { attr.value_str() } else { None }
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})
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}
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/// Traverse and collect the diagnostic items in the current
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fn diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> DiagnosticItems {
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assert_eq!(cnum, LOCAL_CRATE);
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// Initialize the collector.
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let mut collector = DiagnosticItemCollector::new(tcx);
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// Collect diagnostic items in this crate.
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tcx.hir().visit_all_item_likes(&mut collector);
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collector.diagnostic_items
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}
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/// Traverse and collect all the diagnostic items in all crates.
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fn all_diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> DiagnosticItems {
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// Initialize the collector.
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let mut items = DiagnosticItems::default();
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// Collect diagnostic items in other crates.
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for &cnum in tcx.crates(()).iter().chain(std::iter::once(&LOCAL_CRATE)) {
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for (&name, &def_id) in &tcx.diagnostic_items(cnum).name_to_id {
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collect_item(tcx, &mut items, name, def_id);
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}
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}
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items
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}
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pub fn provide(providers: &mut Providers) {
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providers.diagnostic_items = diagnostic_items;
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providers.all_diagnostic_items = all_diagnostic_items;
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}
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