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.
8 use ra_syntax::SmolStr;
9 use rustc_hash::FxHashMap;
12 db::DefDatabase, AdtId, AttrDefId, CrateId, EnumId, FunctionId, ImplId, ModuleDefId, ModuleId,
13 StaticId, StructId, TraitId,
16 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
17 pub enum LangItemTarget {
19 FunctionId(FunctionId),
27 pub fn as_enum(self) -> Option<EnumId> {
29 LangItemTarget::EnumId(id) => Some(id),
34 pub fn as_function(self) -> Option<FunctionId> {
36 LangItemTarget::FunctionId(id) => Some(id),
41 pub fn as_impl_def(self) -> Option<ImplId> {
43 LangItemTarget::ImplDefId(id) => Some(id),
48 pub fn as_static(self) -> Option<StaticId> {
50 LangItemTarget::StaticId(id) => Some(id),
55 pub fn as_struct(self) -> Option<StructId> {
57 LangItemTarget::StructId(id) => Some(id),
62 pub fn as_trait(self) -> Option<TraitId> {
64 LangItemTarget::TraitId(id) => Some(id),
70 #[derive(Default, Debug, Clone, PartialEq, Eq)]
71 pub struct LangItems {
72 items: FxHashMap<SmolStr, LangItemTarget>,
76 pub fn target(&self, item: &str) -> Option<LangItemTarget> {
77 self.items.get(item).copied()
80 /// Salsa query. This will look for lang items in a specific crate.
81 pub(crate) fn crate_lang_items_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<LangItems> {
82 let _p = profile("crate_lang_items_query");
84 let mut lang_items = LangItems::default();
86 let crate_def_map = db.crate_def_map(krate);
91 .filter_map(|(local_id, _)| db.module_lang_items(ModuleId { krate, local_id }))
92 .for_each(|it| lang_items.items.extend(it.items.iter().map(|(k, v)| (k.clone(), *v))));
97 pub(crate) fn module_lang_items_query(
100 ) -> Option<Arc<LangItems>> {
101 let _p = profile("module_lang_items_query");
102 let mut lang_items = LangItems::default();
103 lang_items.collect_lang_items(db, module);
104 if lang_items.items.is_empty() {
107 Some(Arc::new(lang_items))
111 /// Salsa query. Look for a lang item, starting from the specified crate and recursively
112 /// traversing its dependencies.
113 pub(crate) fn lang_item_query(
114 db: &dyn DefDatabase,
115 start_crate: CrateId,
117 ) -> Option<LangItemTarget> {
118 let _p = profile("lang_item_query");
119 let lang_items = db.crate_lang_items(start_crate);
120 let start_crate_target = lang_items.items.get(&item);
121 if let Some(target) = start_crate_target {
122 return Some(*target);
124 db.crate_graph()[start_crate]
127 .find_map(|dep| db.lang_item(dep.crate_id, item.clone()))
130 fn collect_lang_items(&mut self, db: &dyn DefDatabase, module: ModuleId) {
131 // Look for impl targets
132 let def_map = db.crate_def_map(module.krate);
133 let module_data = &def_map[module.local_id];
134 for impl_def in module_data.scope.impls() {
135 self.collect_lang_item(db, impl_def, LangItemTarget::ImplDefId)
138 for def in module_data.scope.declarations() {
140 ModuleDefId::TraitId(trait_) => {
141 self.collect_lang_item(db, trait_, LangItemTarget::TraitId)
143 ModuleDefId::AdtId(AdtId::EnumId(e)) => {
144 self.collect_lang_item(db, e, LangItemTarget::EnumId)
146 ModuleDefId::AdtId(AdtId::StructId(s)) => {
147 self.collect_lang_item(db, s, LangItemTarget::StructId)
149 ModuleDefId::FunctionId(f) => {
150 self.collect_lang_item(db, f, LangItemTarget::FunctionId)
152 ModuleDefId::StaticId(s) => self.collect_lang_item(db, s, LangItemTarget::StaticId),
158 fn collect_lang_item<T>(
160 db: &dyn DefDatabase,
162 constructor: fn(T) -> LangItemTarget,
164 T: Into<AttrDefId> + Copy,
166 if let Some(lang_item_name) = lang_attr(db, item) {
167 self.items.entry(lang_item_name.clone()).or_insert_with(|| constructor(item));
172 pub fn lang_attr(db: &dyn DefDatabase, item: impl Into<AttrDefId> + Copy) -> Option<SmolStr> {
173 let attrs = db.attrs(item.into());
174 attrs.by_key("lang").string_value().cloned()