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: TyCtxt<'_>, diagnostic_items: &mut DiagnosticItems, def_id: LocalDefId) {
22 let hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
23 let attrs = tcx.hir().attrs(hir_id);
24 if let Some(name) = extract(attrs) {
25 // insert into our table
26 collect_item(tcx, diagnostic_items, name, def_id.to_def_id());
30 fn collect_item(tcx: TyCtxt<'_>, items: &mut DiagnosticItems, name: Symbol, item_def_id: DefId) {
31 items.id_to_name.insert(item_def_id, name);
32 if let Some(original_def_id) = items.name_to_id.insert(name, item_def_id) {
33 if original_def_id != item_def_id {
34 let orig_span = tcx.hir().span_if_local(original_def_id);
35 let orig_crate_name = if orig_span.is_some() {
38 Some(tcx.crate_name(original_def_id.krate))
40 match tcx.hir().span_if_local(item_def_id) {
41 Some(span) => tcx.sess.emit_err(DuplicateDiagnosticItem { span, name }),
42 None => tcx.sess.emit_err(DuplicateDiagnosticItemInCrate {
44 orig_crate_name: orig_crate_name.unwrap_or(Empty),
45 have_orig_crate_name: orig_crate_name.map(|_| ()),
46 crate_name: tcx.crate_name(item_def_id.krate),
54 /// Extract the first `rustc_diagnostic_item = "$name"` out of a list of attributes.
55 fn extract(attrs: &[ast::Attribute]) -> Option<Symbol> {
56 attrs.iter().find_map(|attr| {
57 if attr.has_name(sym::rustc_diagnostic_item) { attr.value_str() } else { None }
61 /// Traverse and collect the diagnostic items in the current
62 fn diagnostic_items(tcx: TyCtxt<'_>, cnum: CrateNum) -> DiagnosticItems {
63 assert_eq!(cnum, LOCAL_CRATE);
65 // Initialize the collector.
66 let mut diagnostic_items = DiagnosticItems::default();
68 // Collect diagnostic items in this crate.
69 let crate_items = tcx.hir_crate_items(());
71 for id in crate_items.items() {
72 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
75 for id in crate_items.trait_items() {
76 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
79 for id in crate_items.impl_items() {
80 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
83 for id in crate_items.foreign_items() {
84 observe_item(tcx, &mut diagnostic_items, id.owner_id.def_id);
90 /// Traverse and collect all the diagnostic items in all crates.
91 fn all_diagnostic_items(tcx: TyCtxt<'_>, (): ()) -> DiagnosticItems {
92 // Initialize the collector.
93 let mut items = DiagnosticItems::default();
95 // Collect diagnostic items in other crates.
96 for &cnum in tcx.crates(()).iter().chain(std::iter::once(&LOCAL_CRATE)) {
97 for (&name, &def_id) in &tcx.diagnostic_items(cnum).name_to_id {
98 collect_item(tcx, &mut items, name, def_id);
105 pub fn provide(providers: &mut Providers) {
106 providers.diagnostic_items = diagnostic_items;
107 providers.all_diagnostic_items = all_diagnostic_items;