1 //! This module implements import-resolution/macro expansion algorithm.
3 //! The result of this module is `DefMap`: a data structure which contains:
5 //! * a tree of modules for the crate
6 //! * for each module, a set of items visible in the module (directly declared
9 //! Note that `DefMap` contains fully macro expanded code.
11 //! Computing `DefMap` can be partitioned into several logically
12 //! independent "phases". The phases are mutually recursive though, there's no
15 //! ## Collecting RawItems
17 //! This happens in the `raw` module, which parses a single source file into a
18 //! set of top-level items. Nested imports are desugared to flat imports in this
19 //! phase. Macro calls are represented as a triple of (Path, Option<Name>,
22 //! ## Collecting Modules
24 //! This happens in the `collector` module. In this phase, we recursively walk
25 //! tree of modules, collect raw items from submodules, populate module scopes
26 //! with defined items (so, we assign item ids in this phase) and record the set
27 //! of unresolved imports and macros.
29 //! While we walk tree of modules, we also record macro_rules definitions and
30 //! expand calls to macro_rules defined macros.
32 //! ## Resolving Imports
34 //! We maintain a list of currently unresolved imports. On every iteration, we
35 //! try to resolve some imports from this list. If the import is resolved, we
36 //! record it, by adding an item to current module scope and, if necessary, by
37 //! recursively populating glob imports.
39 //! ## Resolving Macros
41 //! macro_rules from the same crate use a global mutable namespace. We expand
42 //! them immediately, when we collect modules.
44 //! Macros from other crates (including proc-macros) can be used with
45 //! `foo::bar!` syntax. We handle them similarly to imports. There's a list of
46 //! unexpanded macros. On every iteration, we try to resolve each macro call
47 //! path and, upon success, we run macro expansion and "collect module" phase on
50 pub mod attr_resolution;
62 use base_db::{CrateId, Edition, FileId};
63 use hir_expand::{name::Name, InFile, MacroDefId};
66 use rustc_hash::FxHashMap;
68 use syntax::{ast, SmolStr};
72 item_scope::{BuiltinShadowMode, ItemScope},
74 nameres::{diagnostics::DefDiagnostic, path_resolution::ResolveMode},
77 visibility::Visibility,
78 AstId, BlockId, BlockLoc, LocalModuleId, ModuleDefId, ModuleId,
81 use self::proc_macro::ProcMacroDef;
83 /// Contains the results of (early) name resolution.
85 /// A `DefMap` stores the module tree and the definitions that are in scope in every module after
86 /// item-level macros have been expanded.
88 /// Every crate has a primary `DefMap` whose root is the crate's main file (`main.rs`/`lib.rs`),
89 /// computed by the `crate_def_map` query. Additionally, every block expression introduces the
90 /// opportunity to write arbitrary item and module hierarchies, and thus gets its own `DefMap` that
91 /// is computed by the `block_def_map` query.
92 #[derive(Debug, PartialEq, Eq)]
95 block: Option<BlockInfo>,
97 modules: Arena<ModuleData>,
99 /// The prelude module for this crate. This either comes from an import
100 /// marked with the `prelude_import` attribute, or (in the normal case) from
101 /// a dependency (`std` or `core`).
102 prelude: Option<ModuleId>,
103 extern_prelude: FxHashMap<Name, ModuleDefId>,
105 /// Side table with additional proc. macro info, for use by name resolution in downstream
108 /// (the primary purpose is to resolve derive helpers and fetch a proc-macros name)
109 exported_proc_macros: FxHashMap<MacroDefId, ProcMacroDef>,
111 /// Custom attributes registered with `#![register_attr]`.
112 registered_attrs: Vec<SmolStr>,
113 /// Custom tool modules registered with `#![register_tool]`.
114 registered_tools: Vec<SmolStr>,
117 recursion_limit: Option<u32>,
118 diagnostics: Vec<DefDiagnostic>,
121 /// For `DefMap`s computed for a block expression, this stores its location in the parent map.
122 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
124 /// The `BlockId` this `DefMap` was created from.
126 /// The containing module.
130 impl std::ops::Index<LocalModuleId> for DefMap {
131 type Output = ModuleData;
132 fn index(&self, id: LocalModuleId) -> &ModuleData {
137 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
138 pub enum ModuleOrigin {
142 /// Note that non-inline modules, by definition, live inside non-macro file.
145 declaration: AstId<ast::Module>,
149 definition: AstId<ast::Module>,
151 /// Pseudo-module introduced by a block scope (contains only inner items).
153 block: AstId<ast::BlockExpr>,
158 pub fn declaration(&self) -> Option<AstId<ast::Module>> {
160 ModuleOrigin::File { declaration: module, .. }
161 | ModuleOrigin::Inline { definition: module, .. } => Some(*module),
162 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::BlockExpr { .. } => None,
166 pub fn file_id(&self) -> Option<FileId> {
168 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
175 pub fn is_inline(&self) -> bool {
177 ModuleOrigin::Inline { .. } | ModuleOrigin::BlockExpr { .. } => true,
178 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::File { .. } => false,
182 /// Returns a node which defines this module.
183 /// That is, a file or a `mod foo {}` with items.
184 fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
186 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
187 let file_id = *definition;
188 let sf = db.parse(file_id).tree();
189 InFile::new(file_id.into(), ModuleSource::SourceFile(sf))
191 ModuleOrigin::Inline { definition } => InFile::new(
193 ModuleSource::Module(definition.to_node(db.upcast())),
195 ModuleOrigin::BlockExpr { block } => {
196 InFile::new(block.file_id, ModuleSource::BlockExpr(block.to_node(db.upcast())))
202 #[derive(Debug, PartialEq, Eq)]
203 pub struct ModuleData {
204 /// Where does this module come from?
205 pub origin: ModuleOrigin,
206 /// Declared visibility of this module.
207 pub visibility: Visibility,
209 pub parent: Option<LocalModuleId>,
210 pub children: FxHashMap<Name, LocalModuleId>,
211 pub scope: ItemScope,
215 pub(crate) fn crate_def_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<DefMap> {
216 let _p = profile::span("crate_def_map_query").detail(|| {
217 db.crate_graph()[krate].display_name.as_deref().unwrap_or_default().to_string()
220 let crate_graph = db.crate_graph();
222 let edition = crate_graph[krate].edition;
223 let origin = ModuleOrigin::CrateRoot { definition: crate_graph[krate].root_file_id };
224 let def_map = DefMap::empty(krate, edition, origin);
225 let def_map = collector::collect_defs(
228 TreeId::new(crate_graph[krate].root_file_id.into(), None),
234 pub(crate) fn block_def_map_query(
235 db: &dyn DefDatabase,
237 ) -> Option<Arc<DefMap>> {
238 let block: BlockLoc = db.lookup_intern_block(block_id);
240 let tree_id = TreeId::new(block.ast_id.file_id, Some(block_id));
241 let item_tree = tree_id.item_tree(db);
242 if item_tree.top_level_items().is_empty() {
246 let block_info = BlockInfo { block: block_id, parent: block.module };
248 let parent_map = block.module.def_map(db);
249 let mut def_map = DefMap::empty(
252 ModuleOrigin::BlockExpr { block: block.ast_id },
254 def_map.block = Some(block_info);
256 let def_map = collector::collect_defs(db, def_map, tree_id);
257 Some(Arc::new(def_map))
260 fn empty(krate: CrateId, edition: Edition, root_module_origin: ModuleOrigin) -> DefMap {
261 let mut modules: Arena<ModuleData> = Arena::default();
263 let local_id = LocalModuleId::from_raw(la_arena::RawIdx::from(0));
264 // NB: we use `None` as block here, which would be wrong for implicit
265 // modules declared by blocks with items. At the moment, we don't use
266 // this visibility for anything outside IDE, so that's probably OK.
267 let visibility = Visibility::Module(ModuleId { krate, local_id, block: None });
268 let root = modules.alloc(ModuleData::new(root_module_origin, visibility));
269 assert_eq!(local_id, root);
276 recursion_limit: None,
277 extern_prelude: FxHashMap::default(),
278 exported_proc_macros: FxHashMap::default(),
282 registered_attrs: Vec::new(),
283 registered_tools: Vec::new(),
284 diagnostics: Vec::new(),
288 pub fn modules_for_file(&self, file_id: FileId) -> impl Iterator<Item = LocalModuleId> + '_ {
291 .filter(move |(_id, data)| data.origin.file_id() == Some(file_id))
292 .map(|(id, _data)| id)
295 pub fn modules(&self) -> impl Iterator<Item = (LocalModuleId, &ModuleData)> + '_ {
298 pub fn exported_proc_macros(&self) -> impl Iterator<Item = (MacroDefId, Name)> + '_ {
299 self.exported_proc_macros.iter().map(|(id, def)| (*id, def.name.clone()))
301 pub fn registered_tools(&self) -> &[SmolStr] {
302 &self.registered_tools
304 pub fn registered_attrs(&self) -> &[SmolStr] {
305 &self.registered_attrs
307 pub fn root(&self) -> LocalModuleId {
311 pub(crate) fn krate(&self) -> CrateId {
315 pub(crate) fn block_id(&self) -> Option<BlockId> {
316 self.block.as_ref().map(|block| block.block)
319 pub(crate) fn prelude(&self) -> Option<ModuleId> {
323 pub(crate) fn extern_prelude(&self) -> impl Iterator<Item = (&Name, &ModuleDefId)> + '_ {
324 self.extern_prelude.iter()
327 pub fn module_id(&self, local_id: LocalModuleId) -> ModuleId {
328 let block = self.block.as_ref().map(|b| b.block);
329 ModuleId { krate: self.krate, local_id, block }
332 pub(crate) fn crate_root(&self, db: &dyn DefDatabase) -> ModuleId {
333 self.with_ancestor_maps(db, self.root, &mut |def_map, _module| {
334 if def_map.block.is_none() {
335 Some(def_map.module_id(def_map.root))
340 .expect("DefMap chain without root")
343 pub(crate) fn resolve_path(
345 db: &dyn DefDatabase,
346 original_module: LocalModuleId,
348 shadow: BuiltinShadowMode,
349 ) -> (PerNs, Option<usize>) {
351 self.resolve_path_fp_with_macro(db, ResolveMode::Other, original_module, path, shadow);
352 (res.resolved_def, res.segment_index)
355 pub(crate) fn resolve_path_locally(
357 db: &dyn DefDatabase,
358 original_module: LocalModuleId,
360 shadow: BuiltinShadowMode,
361 ) -> (PerNs, Option<usize>) {
362 let res = self.resolve_path_fp_with_macro_single(
369 (res.resolved_def, res.segment_index)
372 /// Ascends the `DefMap` hierarchy and calls `f` with every `DefMap` and containing module.
374 /// If `f` returns `Some(val)`, iteration is stopped and `Some(val)` is returned. If `f` returns
375 /// `None`, iteration continues.
376 pub fn with_ancestor_maps<T>(
378 db: &dyn DefDatabase,
379 local_mod: LocalModuleId,
380 f: &mut dyn FnMut(&DefMap, LocalModuleId) -> Option<T>,
382 if let Some(it) = f(self, local_mod) {
385 let mut block = self.block;
386 while let Some(block_info) = block {
387 let parent = block_info.parent.def_map(db);
388 if let Some(it) = f(&parent, block_info.parent.local_id) {
391 block = parent.block;
397 /// If this `DefMap` is for a block expression, returns the module containing the block (which
398 /// might again be a block, or a module inside a block).
399 pub fn parent(&self) -> Option<ModuleId> {
400 Some(self.block?.parent)
403 /// Returns the module containing `local_mod`, either the parent `mod`, or the module containing
404 /// the block, if `self` corresponds to a block expression.
405 pub fn containing_module(&self, local_mod: LocalModuleId) -> Option<ModuleId> {
406 match &self[local_mod].parent {
407 Some(parent) => Some(self.module_id(*parent)),
408 None => self.block.as_ref().map(|block| block.parent),
412 // FIXME: this can use some more human-readable format (ideally, an IR
413 // even), as this should be a great debugging aid.
414 pub fn dump(&self, db: &dyn DefDatabase) -> String {
415 let mut buf = String::new();
417 let mut current_map = self;
418 while let Some(block) = ¤t_map.block {
419 go(&mut buf, current_map, "block scope", current_map.root);
421 arc = block.parent.def_map(db);
424 go(&mut buf, current_map, "crate", current_map.root);
427 fn go(buf: &mut String, map: &DefMap, path: &str, module: LocalModuleId) {
428 format_to!(buf, "{}\n", path);
430 map.modules[module].scope.dump(buf);
432 for (name, child) in map.modules[module].children.iter() {
433 let path = format!("{}::{}", path, name);
435 go(buf, map, &path, *child);
440 pub fn dump_block_scopes(&self, db: &dyn DefDatabase) -> String {
441 let mut buf = String::new();
443 let mut current_map = self;
444 while let Some(block) = ¤t_map.block {
445 format_to!(buf, "{:?} in {:?}\n", block.block, block.parent);
446 arc = block.parent.def_map(db);
450 format_to!(buf, "crate scope\n");
454 fn shrink_to_fit(&mut self) {
455 // Exhaustive match to require handling new fields.
458 exported_proc_macros,
472 extern_prelude.shrink_to_fit();
473 exported_proc_macros.shrink_to_fit();
474 diagnostics.shrink_to_fit();
475 modules.shrink_to_fit();
476 registered_attrs.shrink_to_fit();
477 registered_tools.shrink_to_fit();
478 for (_, module) in modules.iter_mut() {
479 module.children.shrink_to_fit();
480 module.scope.shrink_to_fit();
484 /// Get a reference to the def map's diagnostics.
485 pub fn diagnostics(&self) -> &[DefDiagnostic] {
486 self.diagnostics.as_slice()
489 pub fn recursion_limit(&self) -> Option<u32> {
495 pub(crate) fn new(origin: ModuleOrigin, visibility: Visibility) -> Self {
500 children: FxHashMap::default(),
501 scope: ItemScope::default(),
505 /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
506 pub fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
507 self.origin.definition_source(db)
510 /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
511 /// `None` for the crate root or block.
512 pub fn declaration_source(&self, db: &dyn DefDatabase) -> Option<InFile<ast::Module>> {
513 let decl = self.origin.declaration()?;
514 let value = decl.to_node(db.upcast());
515 Some(InFile { file_id: decl.file_id, value })
519 #[derive(Debug, Clone, PartialEq, Eq)]
520 pub enum ModuleSource {
521 SourceFile(ast::SourceFile),
523 BlockExpr(ast::BlockExpr),