1 //! Collects lang items: items marked with `#[lang = "..."]` attribute.
3 //! This attribute to tell the compiler about semi built-in std library
4 //! features, such as Fn family of traits.
7 use ra_syntax::SmolStr;
8 use rustc_hash::FxHashMap;
11 db::DefDatabase, AdtId, AttrDefId, CrateId, EnumId, FunctionId, ImplId, ModuleDefId, ModuleId,
12 StaticId, StructId, TraitId,
15 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
16 pub enum LangItemTarget {
18 FunctionId(FunctionId),
25 #[derive(Default, Debug, Clone, PartialEq, Eq)]
26 pub struct LangItems {
27 items: FxHashMap<SmolStr, LangItemTarget>,
31 pub fn target<'a>(&'a self, item: &str) -> Option<&'a LangItemTarget> {
35 /// Salsa query. This will look for lang items in a specific crate.
36 pub(crate) fn crate_lang_items_query(db: &impl DefDatabase, krate: CrateId) -> Arc<LangItems> {
37 let mut lang_items = LangItems::default();
39 let crate_def_map = db.crate_def_map(krate);
44 .filter_map(|(local_id, _)| db.module_lang_items(ModuleId { krate, local_id }))
45 .for_each(|it| lang_items.items.extend(it.items.iter().map(|(k, v)| (k.clone(), *v))));
50 pub(crate) fn module_lang_items_query(
51 db: &impl DefDatabase,
53 ) -> Option<Arc<LangItems>> {
54 let mut lang_items = LangItems::default();
55 lang_items.collect_lang_items(db, module);
56 if lang_items.items.is_empty() {
59 Some(Arc::new(lang_items))
63 /// Salsa query. Look for a lang item, starting from the specified crate and recursively
64 /// traversing its dependencies.
65 pub(crate) fn lang_item_query(
66 db: &impl DefDatabase,
69 ) -> Option<LangItemTarget> {
70 let lang_items = db.crate_lang_items(start_crate);
71 let start_crate_target = lang_items.items.get(&item);
72 if let Some(target) = start_crate_target {
76 .dependencies(start_crate)
77 .find_map(|dep| db.lang_item(dep.crate_id, item.clone()))
80 fn collect_lang_items(&mut self, db: &impl DefDatabase, module: ModuleId) {
81 // Look for impl targets
82 let def_map = db.crate_def_map(module.krate);
83 let module_data = &def_map[module.local_id];
84 for impl_block in module_data.scope.impls() {
85 self.collect_lang_item(db, impl_block, LangItemTarget::ImplBlockId)
88 for def in module_data.scope.declarations() {
90 ModuleDefId::TraitId(trait_) => {
91 self.collect_lang_item(db, trait_, LangItemTarget::TraitId)
93 ModuleDefId::AdtId(AdtId::EnumId(e)) => {
94 self.collect_lang_item(db, e, LangItemTarget::EnumId)
96 ModuleDefId::AdtId(AdtId::StructId(s)) => {
97 self.collect_lang_item(db, s, LangItemTarget::StructId)
99 ModuleDefId::FunctionId(f) => {
100 self.collect_lang_item(db, f, LangItemTarget::FunctionId)
102 ModuleDefId::StaticId(s) => self.collect_lang_item(db, s, LangItemTarget::StaticId),
108 fn collect_lang_item<T>(
110 db: &impl DefDatabase,
112 constructor: fn(T) -> LangItemTarget,
114 T: Into<AttrDefId> + Copy,
116 let attrs = db.attrs(item.into());
117 if let Some(lang_item_name) = attrs.by_key("lang").string_value() {
118 self.items.entry(lang_item_name.clone()).or_insert_with(|| constructor(item));