1 //! Detecting diagnostic items.
3 //! Diagnostic items are items that are not language-inherent, but can reasonably be expected to
4 //! exist for diagnostic purposes. This allows diagnostic authors to refer to specific items
5 //! directly, without having to guess module paths and crates.
8 //! * Traits like `Debug`, that have no bearing on language semantics
10 //! * Compiler internal types like `Ty` and `TyCtxt`
13 use rustc_hir::diagnostic_items::DiagnosticItems;
14 use rustc_middle::ty::query::Providers;
15 use rustc_middle::ty::TyCtxt;
16 use rustc_span::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE};
17 use rustc_span::symbol::{kw::Empty, sym, Symbol};
19 use crate::errors::{DuplicateDiagnosticItem, DuplicateDiagnosticItemInCrate};
21 fn observe_item<'tcx>(
23 diagnostic_items: &mut DiagnosticItems,
26 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
27 let attrs = tcx.hir().attrs(hir_id);
28 if let Some(name) = extract(attrs) {
29 // insert into our table
30 collect_item(tcx, diagnostic_items, name, def_id.to_def_id());
34 fn collect_item(tcx: TyCtxt<'_>, items: &mut DiagnosticItems, name: Symbol, item_def_id: DefId) {
35 items.id_to_name.insert(item_def_id, name);
36 if let Some(original_def_id) = items.name_to_id.insert(name, item_def_id) {
37 if original_def_id != item_def_id {
38 let orig_span = tcx.hir().span_if_local(original_def_id);
39 let orig_crate_name = if orig_span.is_some() {
42 Some(tcx.crate_name(original_def_id.krate))
44 match tcx.hir().span_if_local(item_def_id) {
45 Some(span) => tcx.sess.emit_err(DuplicateDiagnosticItem { span, name }),
46 None => tcx.sess.emit_err(DuplicateDiagnosticItemInCrate {
48 orig_crate_name: orig_crate_name.unwrap_or(Empty),
49 have_orig_crate_name: orig_crate_name.map(|_| ()),
50 crate_name: tcx.crate_name(item_def_id.krate),
58 /// Extract the first `rustc_diagnostic_item = "$name"` out of a list of attributes.
59 fn extract(attrs: &[ast::Attribute]) -> Option<Symbol> {
60 attrs.iter().find_map(|attr| {
61 if attr.has_name(sym::rustc_diagnostic_item) { attr.value_str() } else { None }
65 /// Traverse and collect the diagnostic items in the current
66 fn diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, cnum: CrateNum) -> DiagnosticItems {
67 assert_eq!(cnum, LOCAL_CRATE);
69 // Initialize the collector.
70 let mut diagnostic_items = DiagnosticItems::default();
72 // Collect diagnostic items in this crate.
73 let crate_items = tcx.hir_crate_items(());
75 for id in crate_items.items() {
76 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
79 for id in crate_items.trait_items() {
80 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
83 for id in crate_items.impl_items() {
84 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
87 for id in crate_items.foreign_items() {
88 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
94 /// Traverse and collect all the diagnostic items in all crates.
95 fn all_diagnostic_items<'tcx>(tcx: TyCtxt<'tcx>, (): ()) -> DiagnosticItems {
96 // Initialize the collector.
97 let mut items = DiagnosticItems::default();
99 // Collect diagnostic items in other crates.
100 for &cnum in tcx.crates(()).iter().chain(std::iter::once(&LOCAL_CRATE)) {
101 for (&name, &def_id) in &tcx.diagnostic_items(cnum).name_to_id {
102 collect_item(tcx, &mut items, name, def_id);
109 pub fn provide(providers: &mut Providers) {
110 providers.diagnostic_items = diagnostic_items;
111 providers.all_diagnostic_items = all_diagnostic_items;