1 //! Maps *syntax* of various definitions to their semantic ids.
3 //! This is a very interesting module, and, in some sense, can be considered the
4 //! heart of the IDE parts of rust-analyzer.
6 //! This module solves the following problem:
8 //! Given a piece of syntax, find the corresponding semantic definition (def).
10 //! This problem is a part of more-or-less every IDE feature implemented. Every
11 //! IDE functionality (like goto to definition), conceptually starts with a
12 //! specific cursor position in a file. Starting with this text offset, we first
13 //! figure out what syntactic construct are we at: is this a pattern, an
14 //! expression, an item definition.
16 //! Knowing only the syntax gives us relatively little info. For example,
17 //! looking at the syntax of the function we can realise that it is a part of an
18 //! `impl` block, but we won't be able to tell what trait function the current
19 //! function overrides, and whether it does that correctly. For that, we need to
20 //! go from [`ast::Fn`] to [`crate::Function`], and that's exactly what this
23 //! As syntax trees are values and don't know their place of origin/identity,
24 //! this module also requires [`InFile`] wrappers to understand which specific
25 //! real or macro-expanded file the tree comes from.
27 //! The actual algorithm to resolve syntax to def is curious in two aspects:
30 //! * It uses the inverse algorithm (what is the syntax for this def?)
32 //! Specifically, the algorithm goes like this:
34 //! 1. Find the syntactic container for the syntax. For example, field's
35 //! container is the struct, and structs container is a module.
36 //! 2. Recursively get the def corresponding to container.
37 //! 3. Ask the container def for all child defs. These child defs contain
38 //! the answer and answer's siblings.
39 //! 4. For each child def, ask for it's source.
40 //! 5. The child def whose source is the syntax node we've started with
43 //! It's interesting that both Roslyn and Kotlin contain very similar code
46 //! Let's take a look at Roslyn:
48 //! <https://github.com/dotnet/roslyn/blob/36a0c338d6621cc5fe34b79d414074a95a6a489c/src/Compilers/CSharp/Portable/Compilation/SyntaxTreeSemanticModel.cs#L1403-L1429>
49 //! <https://sourceroslyn.io/#Microsoft.CodeAnalysis.CSharp/Compilation/SyntaxTreeSemanticModel.cs,1403>
51 //! The `GetDeclaredType` takes `Syntax` as input, and returns `Symbol` as
52 //! output. First, it retrieves a `Symbol` for parent `Syntax`:
54 //! * <https://sourceroslyn.io/#Microsoft.CodeAnalysis.CSharp/Compilation/SyntaxTreeSemanticModel.cs,1423>
56 //! Then, it iterates parent symbol's children, looking for one which has the
57 //! same text span as the original node:
59 //! <https://sourceroslyn.io/#Microsoft.CodeAnalysis.CSharp/Compilation/SyntaxTreeSemanticModel.cs,1786>
61 //! Now, let's look at Kotlin:
63 //! <https://github.com/JetBrains/kotlin/blob/a288b8b00e4754a1872b164999c6d3f3b8c8994a/idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/FirModuleResolveStateImpl.kt#L93-L125>
65 //! This function starts with a syntax node (`KtExpression` is syntax, like all
66 //! `Kt` nodes), and returns a def. It uses
67 //! `getNonLocalContainingOrThisDeclaration` to get syntactic container for a
68 //! current node. Then, `findSourceNonLocalFirDeclaration` gets `Fir` for this
69 //! parent. Finally, `findElementIn` function traverses `Fir` children to find
70 //! one with the same source we originally started with.
72 //! One question is left though -- where does the recursion stops? This happens
73 //! when we get to the file syntax node, which doesn't have a syntactic parent.
74 //! In that case, we loop through all the crates that might contain this file
75 //! and look for a module whose source is the given file.
77 //! Note that the logic in this module is somewhat fundamentally imprecise --
78 //! due to conditional compilation and `#[path]` attributes, there's no
79 //! injective mapping from syntax nodes to defs. This is not an edge case --
80 //! more or less every item in a `lib.rs` is a part of two distinct crates: a
81 //! library with `--cfg test` and a library without.
83 //! At the moment, we don't really handle this well and return the first answer
84 //! that works. Ideally, we should first let the caller to pick a specific
85 //! active crate for a given position, and then provide an API to resolve all
86 //! syntax nodes against this specific crate.
91 child_by_source::ChildBySource,
93 expr::{LabelId, PatId},
95 AdtId, ConstId, ConstParamId, DefWithBodyId, EnumId, EnumVariantId, FieldId, FunctionId,
96 GenericDefId, GenericParamId, ImplId, LifetimeParamId, MacroId, ModuleId, StaticId, StructId,
97 TraitId, TypeAliasId, TypeParamId, UnionId, VariantId,
99 use hir_expand::{name::AsName, HirFileId, MacroCallId};
100 use rustc_hash::FxHashMap;
101 use smallvec::SmallVec;
104 ast::{self, HasName},
108 use crate::{db::HirDatabase, InFile};
110 pub(super) type SourceToDefCache = FxHashMap<(ChildContainer, HirFileId), DynMap>;
112 pub(super) struct SourceToDefCtx<'a, 'b> {
113 pub(super) db: &'b dyn HirDatabase,
114 pub(super) cache: &'a mut SourceToDefCache,
117 impl SourceToDefCtx<'_, '_> {
118 pub(super) fn file_to_def(&mut self, file: FileId) -> SmallVec<[ModuleId; 1]> {
119 let _p = profile::span("SourceBinder::to_module_def");
120 let mut mods = SmallVec::new();
121 for &crate_id in self.db.relevant_crates(file).iter() {
122 // FIXME: inner items
123 let crate_def_map = self.db.crate_def_map(crate_id);
126 .modules_for_file(file)
127 .map(|local_id| crate_def_map.module_id(local_id)),
133 pub(super) fn module_to_def(&mut self, src: InFile<ast::Module>) -> Option<ModuleId> {
134 let _p = profile::span("module_to_def");
135 let parent_declaration = src
137 .ancestors_with_macros_skip_attr_item(self.db.upcast())
138 .find_map(|it| it.map(ast::Module::cast).transpose());
140 let parent_module = match parent_declaration {
141 Some(parent_declaration) => self.module_to_def(parent_declaration),
143 let file_id = src.file_id.original_file(self.db.upcast());
144 self.file_to_def(file_id).get(0).copied()
148 let child_name = src.value.name()?.as_name();
149 let def_map = parent_module.def_map(self.db.upcast());
150 let &child_id = def_map[parent_module.local_id].children.get(&child_name)?;
151 Some(def_map.module_id(child_id))
154 pub(super) fn source_file_to_def(&mut self, src: InFile<ast::SourceFile>) -> Option<ModuleId> {
155 let _p = profile::span("source_file_to_def");
156 let file_id = src.file_id.original_file(self.db.upcast());
157 self.file_to_def(file_id).get(0).copied()
160 pub(super) fn trait_to_def(&mut self, src: InFile<ast::Trait>) -> Option<TraitId> {
161 self.to_def(src, keys::TRAIT)
163 pub(super) fn impl_to_def(&mut self, src: InFile<ast::Impl>) -> Option<ImplId> {
164 self.to_def(src, keys::IMPL)
166 pub(super) fn fn_to_def(&mut self, src: InFile<ast::Fn>) -> Option<FunctionId> {
167 self.to_def(src, keys::FUNCTION)
169 pub(super) fn struct_to_def(&mut self, src: InFile<ast::Struct>) -> Option<StructId> {
170 self.to_def(src, keys::STRUCT)
172 pub(super) fn enum_to_def(&mut self, src: InFile<ast::Enum>) -> Option<EnumId> {
173 self.to_def(src, keys::ENUM)
175 pub(super) fn union_to_def(&mut self, src: InFile<ast::Union>) -> Option<UnionId> {
176 self.to_def(src, keys::UNION)
178 pub(super) fn static_to_def(&mut self, src: InFile<ast::Static>) -> Option<StaticId> {
179 self.to_def(src, keys::STATIC)
181 pub(super) fn const_to_def(&mut self, src: InFile<ast::Const>) -> Option<ConstId> {
182 self.to_def(src, keys::CONST)
184 pub(super) fn type_alias_to_def(&mut self, src: InFile<ast::TypeAlias>) -> Option<TypeAliasId> {
185 self.to_def(src, keys::TYPE_ALIAS)
187 pub(super) fn record_field_to_def(&mut self, src: InFile<ast::RecordField>) -> Option<FieldId> {
188 self.to_def(src, keys::RECORD_FIELD)
190 pub(super) fn tuple_field_to_def(&mut self, src: InFile<ast::TupleField>) -> Option<FieldId> {
191 self.to_def(src, keys::TUPLE_FIELD)
193 pub(super) fn enum_variant_to_def(
195 src: InFile<ast::Variant>,
196 ) -> Option<EnumVariantId> {
197 self.to_def(src, keys::VARIANT)
199 pub(super) fn adt_to_def(
201 InFile { file_id, value }: InFile<ast::Adt>,
204 ast::Adt::Enum(it) => self.enum_to_def(InFile::new(file_id, it)).map(AdtId::EnumId),
205 ast::Adt::Struct(it) => {
206 self.struct_to_def(InFile::new(file_id, it)).map(AdtId::StructId)
208 ast::Adt::Union(it) => self.union_to_def(InFile::new(file_id, it)).map(AdtId::UnionId),
211 pub(super) fn bind_pat_to_def(
213 src: InFile<ast::IdentPat>,
214 ) -> Option<(DefWithBodyId, PatId)> {
215 let container = self.find_pat_or_label_container(src.syntax())?;
216 let (_body, source_map) = self.db.body_with_source_map(container);
217 let src = src.map(ast::Pat::from);
218 let pat_id = source_map.node_pat(src.as_ref())?;
219 Some((container, pat_id))
221 pub(super) fn self_param_to_def(
223 src: InFile<ast::SelfParam>,
224 ) -> Option<(DefWithBodyId, PatId)> {
225 let container = self.find_pat_or_label_container(src.syntax())?;
226 let (_body, source_map) = self.db.body_with_source_map(container);
227 let pat_id = source_map.node_self_param(src.as_ref())?;
228 Some((container, pat_id))
230 pub(super) fn label_to_def(
232 src: InFile<ast::Label>,
233 ) -> Option<(DefWithBodyId, LabelId)> {
234 let container = self.find_pat_or_label_container(src.syntax())?;
235 let (_body, source_map) = self.db.body_with_source_map(container);
236 let label_id = source_map.node_label(src.as_ref())?;
237 Some((container, label_id))
240 pub(super) fn item_to_macro_call(&mut self, src: InFile<ast::Item>) -> Option<MacroCallId> {
241 let map = self.dyn_map(src.as_ref())?;
242 map[keys::ATTR_MACRO_CALL].get(&src.value).copied()
245 pub(super) fn attr_to_derive_macro_call(
247 item: InFile<&ast::Adt>,
248 src: InFile<ast::Attr>,
249 ) -> Option<(AttrId, MacroCallId, &[Option<MacroCallId>])> {
250 let map = self.dyn_map(item)?;
251 map[keys::DERIVE_MACRO_CALL]
253 .map(|&(attr_id, call_id, ref ids)| (attr_id, call_id, &**ids))
255 pub(super) fn has_derives(&mut self, adt: InFile<&ast::Adt>) -> bool {
256 self.dyn_map(adt).as_ref().map_or(false, |map| !map[keys::DERIVE_MACRO_CALL].is_empty())
259 fn to_def<Ast: AstNode + 'static, ID: Copy + 'static>(
264 self.dyn_map(src.as_ref())?[key].get(&src.value).copied()
267 fn dyn_map<Ast: AstNode + 'static>(&mut self, src: InFile<&Ast>) -> Option<&DynMap> {
268 let container = self.find_container(src.map(|it| it.syntax()))?;
269 Some(self.cache_for(container, src.file_id))
272 fn cache_for(&mut self, container: ChildContainer, file_id: HirFileId) -> &DynMap {
275 .entry((container, file_id))
276 .or_insert_with(|| container.child_by_source(db, file_id))
279 pub(super) fn type_param_to_def(&mut self, src: InFile<ast::TypeParam>) -> Option<TypeParamId> {
280 let container: ChildContainer = self.find_generic_param_container(src.syntax())?.into();
281 let dyn_map = self.cache_for(container, src.file_id);
282 dyn_map[keys::TYPE_PARAM].get(&src.value).copied().map(|x| TypeParamId::from_unchecked(x))
285 pub(super) fn lifetime_param_to_def(
287 src: InFile<ast::LifetimeParam>,
288 ) -> Option<LifetimeParamId> {
289 let container: ChildContainer = self.find_generic_param_container(src.syntax())?.into();
290 let dyn_map = self.cache_for(container, src.file_id);
291 dyn_map[keys::LIFETIME_PARAM].get(&src.value).copied()
294 pub(super) fn const_param_to_def(
296 src: InFile<ast::ConstParam>,
297 ) -> Option<ConstParamId> {
298 let container: ChildContainer = self.find_generic_param_container(src.syntax())?.into();
299 let dyn_map = self.cache_for(container, src.file_id);
300 dyn_map[keys::CONST_PARAM].get(&src.value).copied().map(|x| ConstParamId::from_unchecked(x))
303 pub(super) fn generic_param_to_def(
305 InFile { file_id, value }: InFile<ast::GenericParam>,
306 ) -> Option<GenericParamId> {
308 ast::GenericParam::ConstParam(it) => {
309 self.const_param_to_def(InFile::new(file_id, it)).map(GenericParamId::ConstParamId)
311 ast::GenericParam::LifetimeParam(it) => self
312 .lifetime_param_to_def(InFile::new(file_id, it))
313 .map(GenericParamId::LifetimeParamId),
314 ast::GenericParam::TypeParam(it) => {
315 self.type_param_to_def(InFile::new(file_id, it)).map(GenericParamId::TypeParamId)
320 pub(super) fn macro_to_def(&mut self, src: InFile<ast::Macro>) -> Option<MacroId> {
321 self.dyn_map(src.as_ref()).and_then(|it| match &src.value {
322 ast::Macro::MacroRules(value) => {
323 it[keys::MACRO_RULES].get(value).copied().map(MacroId::from)
325 ast::Macro::MacroDef(value) => it[keys::MACRO2].get(value).copied().map(MacroId::from),
329 pub(super) fn proc_macro_to_def(&mut self, src: InFile<ast::Fn>) -> Option<MacroId> {
330 self.dyn_map(src.as_ref())
331 .and_then(|it| it[keys::PROC_MACRO].get(&src.value).copied().map(MacroId::from))
334 pub(super) fn find_container(&mut self, src: InFile<&SyntaxNode>) -> Option<ChildContainer> {
335 for container in src.ancestors_with_macros_skip_attr_item(self.db.upcast()) {
336 if let Some(res) = self.container_to_def(container) {
341 let def = self.file_to_def(src.file_id.original_file(self.db.upcast())).get(0).copied()?;
345 fn container_to_def(&mut self, container: InFile<SyntaxNode>) -> Option<ChildContainer> {
346 let cont = if let Some(item) = ast::Item::cast(container.value.clone()) {
348 ast::Item::Module(it) => self.module_to_def(container.with_value(it))?.into(),
349 ast::Item::Trait(it) => self.trait_to_def(container.with_value(it))?.into(),
350 ast::Item::Impl(it) => self.impl_to_def(container.with_value(it))?.into(),
351 ast::Item::Enum(it) => self.enum_to_def(container.with_value(it))?.into(),
352 ast::Item::TypeAlias(it) => {
353 self.type_alias_to_def(container.with_value(it))?.into()
355 ast::Item::Struct(it) => {
356 let def = self.struct_to_def(container.with_value(it))?;
357 VariantId::from(def).into()
359 ast::Item::Union(it) => {
360 let def = self.union_to_def(container.with_value(it))?;
361 VariantId::from(def).into()
363 ast::Item::Fn(it) => {
364 let def = self.fn_to_def(container.with_value(it))?;
365 DefWithBodyId::from(def).into()
367 ast::Item::Static(it) => {
368 let def = self.static_to_def(container.with_value(it))?;
369 DefWithBodyId::from(def).into()
371 ast::Item::Const(it) => {
372 let def = self.const_to_def(container.with_value(it))?;
373 DefWithBodyId::from(def).into()
378 let it = ast::Variant::cast(container.value)?;
379 let def = self.enum_variant_to_def(InFile::new(container.file_id, it))?;
380 VariantId::from(def).into()
385 fn find_generic_param_container(&mut self, src: InFile<&SyntaxNode>) -> Option<GenericDefId> {
386 let ancestors = src.ancestors_with_macros_skip_attr_item(self.db.upcast());
387 for InFile { file_id, value } in ancestors {
388 let item = match ast::Item::cast(value) {
392 let res: GenericDefId = match item {
393 ast::Item::Fn(it) => self.fn_to_def(InFile::new(file_id, it))?.into(),
394 ast::Item::Struct(it) => self.struct_to_def(InFile::new(file_id, it))?.into(),
395 ast::Item::Enum(it) => self.enum_to_def(InFile::new(file_id, it))?.into(),
396 ast::Item::Trait(it) => self.trait_to_def(InFile::new(file_id, it))?.into(),
397 ast::Item::TypeAlias(it) => {
398 self.type_alias_to_def(InFile::new(file_id, it))?.into()
400 ast::Item::Impl(it) => self.impl_to_def(InFile::new(file_id, it))?.into(),
408 fn find_pat_or_label_container(&mut self, src: InFile<&SyntaxNode>) -> Option<DefWithBodyId> {
409 let ancestors = src.ancestors_with_macros_skip_attr_item(self.db.upcast());
410 for InFile { file_id, value } in ancestors {
411 let item = match ast::Item::cast(value) {
415 let res: DefWithBodyId = match item {
416 ast::Item::Const(it) => self.const_to_def(InFile::new(file_id, it))?.into(),
417 ast::Item::Static(it) => self.static_to_def(InFile::new(file_id, it))?.into(),
418 ast::Item::Fn(it) => self.fn_to_def(InFile::new(file_id, it))?.into(),
427 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
428 pub(crate) enum ChildContainer {
429 DefWithBodyId(DefWithBodyId),
434 VariantId(VariantId),
435 TypeAliasId(TypeAliasId),
436 /// XXX: this might be the same def as, for example an `EnumId`. However,
437 /// here the children are generic parameters, and not, eg enum variants.
438 GenericDefId(GenericDefId),
452 impl ChildContainer {
453 fn child_by_source(self, db: &dyn HirDatabase, file_id: HirFileId) -> DynMap {
454 let db = db.upcast();
456 ChildContainer::DefWithBodyId(it) => it.child_by_source(db, file_id),
457 ChildContainer::ModuleId(it) => it.child_by_source(db, file_id),
458 ChildContainer::TraitId(it) => it.child_by_source(db, file_id),
459 ChildContainer::ImplId(it) => it.child_by_source(db, file_id),
460 ChildContainer::EnumId(it) => it.child_by_source(db, file_id),
461 ChildContainer::VariantId(it) => it.child_by_source(db, file_id),
462 ChildContainer::TypeAliasId(_) => DynMap::default(),
463 ChildContainer::GenericDefId(it) => it.child_by_source(db, file_id),