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
61 use base_db::{CrateId, Edition, FileId};
62 use hir_expand::{name::Name, InFile, MacroDefId};
65 use rustc_hash::FxHashMap;
71 item_scope::{BuiltinShadowMode, ItemScope},
72 nameres::{diagnostics::DefDiagnostic, path_resolution::ResolveMode},
75 visibility::Visibility,
76 AstId, BlockId, BlockLoc, LocalModuleId, ModuleDefId, ModuleId,
79 use self::proc_macro::ProcMacroDef;
81 /// Contains the results of (early) name resolution.
83 /// A `DefMap` stores the module tree and the definitions that are in scope in every module after
84 /// item-level macros have been expanded.
86 /// Every crate has a primary `DefMap` whose root is the crate's main file (`main.rs`/`lib.rs`),
87 /// computed by the `crate_def_map` query. Additionally, every block expression introduces the
88 /// opportunity to write arbitrary item and module hierarchies, and thus gets its own `DefMap` that
89 /// is computed by the `block_def_map` query.
90 #[derive(Debug, PartialEq, Eq)]
93 block: Option<BlockInfo>,
95 modules: Arena<ModuleData>,
97 /// The prelude module for this crate. This either comes from an import
98 /// marked with the `prelude_import` attribute, or (in the normal case) from
99 /// a dependency (`std` or `core`).
100 prelude: Option<ModuleId>,
101 extern_prelude: FxHashMap<Name, ModuleDefId>,
103 /// Side table with additional proc. macro info, for use by name resolution in downstream
106 /// (the primary purpose is to resolve derive helpers and fetch a proc-macros name)
107 exported_proc_macros: FxHashMap<MacroDefId, ProcMacroDef>,
110 diagnostics: Vec<DefDiagnostic>,
113 /// For `DefMap`s computed for a block expression, this stores its location in the parent map.
114 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
116 /// The `BlockId` this `DefMap` was created from.
118 /// The containing module.
122 impl std::ops::Index<LocalModuleId> for DefMap {
123 type Output = ModuleData;
124 fn index(&self, id: LocalModuleId) -> &ModuleData {
129 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
130 pub enum ModuleOrigin {
134 /// Note that non-inline modules, by definition, live inside non-macro file.
137 declaration: AstId<ast::Module>,
141 definition: AstId<ast::Module>,
143 /// Pseudo-module introduced by a block scope (contains only inner items).
145 block: AstId<ast::BlockExpr>,
150 fn declaration(&self) -> Option<AstId<ast::Module>> {
152 ModuleOrigin::File { declaration: module, .. }
153 | ModuleOrigin::Inline { definition: module, .. } => Some(*module),
154 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::BlockExpr { .. } => None,
158 pub fn file_id(&self) -> Option<FileId> {
160 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
167 pub fn is_inline(&self) -> bool {
169 ModuleOrigin::Inline { .. } | ModuleOrigin::BlockExpr { .. } => true,
170 ModuleOrigin::CrateRoot { .. } | ModuleOrigin::File { .. } => false,
174 /// Returns a node which defines this module.
175 /// That is, a file or a `mod foo {}` with items.
176 fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
178 ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
179 let file_id = *definition;
180 let sf = db.parse(file_id).tree();
181 InFile::new(file_id.into(), ModuleSource::SourceFile(sf))
183 ModuleOrigin::Inline { definition } => InFile::new(
185 ModuleSource::Module(definition.to_node(db.upcast())),
187 ModuleOrigin::BlockExpr { block } => {
188 InFile::new(block.file_id, ModuleSource::BlockExpr(block.to_node(db.upcast())))
194 #[derive(Debug, PartialEq, Eq)]
195 pub struct ModuleData {
196 /// Where does this module come from?
197 pub origin: ModuleOrigin,
198 /// Declared visibility of this module.
199 pub visibility: Visibility,
201 pub parent: Option<LocalModuleId>,
202 pub children: FxHashMap<Name, LocalModuleId>,
203 pub scope: ItemScope,
207 pub(crate) fn crate_def_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<DefMap> {
208 let _p = profile::span("crate_def_map_query").detail(|| {
209 db.crate_graph()[krate].display_name.as_deref().unwrap_or_default().to_string()
212 let crate_graph = db.crate_graph();
214 let edition = crate_graph[krate].edition;
215 let origin = ModuleOrigin::CrateRoot { definition: crate_graph[krate].root_file_id };
216 let def_map = DefMap::empty(krate, edition, origin);
217 let def_map = collector::collect_defs(db, def_map, None);
222 pub(crate) fn block_def_map_query(
223 db: &dyn DefDatabase,
225 ) -> Option<Arc<DefMap>> {
226 let block: BlockLoc = db.lookup_intern_block(block_id);
228 let item_tree = db.file_item_tree(block.ast_id.file_id);
229 if item_tree.inner_items_of_block(block.ast_id.value).is_empty() {
233 let block_info = BlockInfo { block: block_id, parent: block.module };
235 let parent_map = block.module.def_map(db);
236 let mut def_map = DefMap::empty(
239 ModuleOrigin::BlockExpr { block: block.ast_id },
241 def_map.block = Some(block_info);
243 let def_map = collector::collect_defs(db, def_map, Some(block.ast_id));
244 Some(Arc::new(def_map))
247 fn empty(krate: CrateId, edition: Edition, root_module_origin: ModuleOrigin) -> DefMap {
248 let mut modules: Arena<ModuleData> = Arena::default();
250 let local_id = LocalModuleId::from_raw(la_arena::RawIdx::from(0));
251 // NB: we use `None` as block here, which would be wrong for implicit
252 // modules declared by blocks with items. At the moment, we don't use
253 // this visibility for anything outside IDE, so that's probably OK.
254 let visibility = Visibility::Module(ModuleId { krate, local_id, block: None });
255 let root = modules.alloc(ModuleData::new(root_module_origin, visibility));
256 assert_eq!(local_id, root);
263 extern_prelude: FxHashMap::default(),
264 exported_proc_macros: FxHashMap::default(),
268 diagnostics: Vec::new(),
272 pub fn modules_for_file(&self, file_id: FileId) -> impl Iterator<Item = LocalModuleId> + '_ {
275 .filter(move |(_id, data)| data.origin.file_id() == Some(file_id))
276 .map(|(id, _data)| id)
279 pub fn modules(&self) -> impl Iterator<Item = (LocalModuleId, &ModuleData)> + '_ {
282 pub fn exported_proc_macros(&self) -> impl Iterator<Item = (MacroDefId, Name)> + '_ {
283 self.exported_proc_macros.iter().map(|(id, def)| (*id, def.name.clone()))
285 pub fn root(&self) -> LocalModuleId {
289 pub(crate) fn krate(&self) -> CrateId {
293 pub(crate) fn block_id(&self) -> Option<BlockId> {
294 self.block.as_ref().map(|block| block.block)
297 pub(crate) fn prelude(&self) -> Option<ModuleId> {
301 pub(crate) fn extern_prelude(&self) -> impl Iterator<Item = (&Name, &ModuleDefId)> + '_ {
302 self.extern_prelude.iter()
305 pub fn module_id(&self, local_id: LocalModuleId) -> ModuleId {
306 let block = self.block.as_ref().map(|b| b.block);
307 ModuleId { krate: self.krate, local_id, block }
310 pub(crate) fn crate_root(&self, db: &dyn DefDatabase) -> ModuleId {
311 self.with_ancestor_maps(db, self.root, &mut |def_map, _module| {
312 if def_map.block.is_none() {
313 Some(def_map.module_id(def_map.root))
318 .expect("DefMap chain without root")
321 pub(crate) fn resolve_path(
323 db: &dyn DefDatabase,
324 original_module: LocalModuleId,
326 shadow: BuiltinShadowMode,
327 ) -> (PerNs, Option<usize>) {
329 self.resolve_path_fp_with_macro(db, ResolveMode::Other, original_module, path, shadow);
330 (res.resolved_def, res.segment_index)
333 pub(crate) fn resolve_path_locally(
335 db: &dyn DefDatabase,
336 original_module: LocalModuleId,
338 shadow: BuiltinShadowMode,
339 ) -> (PerNs, Option<usize>) {
340 let res = self.resolve_path_fp_with_macro_single(
347 (res.resolved_def, res.segment_index)
350 /// Ascends the `DefMap` hierarchy and calls `f` with every `DefMap` and containing module.
352 /// If `f` returns `Some(val)`, iteration is stopped and `Some(val)` is returned. If `f` returns
353 /// `None`, iteration continues.
354 pub fn with_ancestor_maps<T>(
356 db: &dyn DefDatabase,
357 local_mod: LocalModuleId,
358 f: &mut dyn FnMut(&DefMap, LocalModuleId) -> Option<T>,
360 if let Some(it) = f(self, local_mod) {
363 let mut block = self.block;
364 while let Some(block_info) = block {
365 let parent = block_info.parent.def_map(db);
366 if let Some(it) = f(&parent, block_info.parent.local_id) {
369 block = parent.block;
375 /// If this `DefMap` is for a block expression, returns the module containing the block (which
376 /// might again be a block, or a module inside a block).
377 pub fn parent(&self) -> Option<ModuleId> {
378 Some(self.block?.parent)
381 /// Returns the module containing `local_mod`, either the parent `mod`, or the module containing
382 /// the block, if `self` corresponds to a block expression.
383 pub fn containing_module(&self, local_mod: LocalModuleId) -> Option<ModuleId> {
384 match &self[local_mod].parent {
385 Some(parent) => Some(self.module_id(*parent)),
386 None => self.block.as_ref().map(|block| block.parent),
390 // FIXME: this can use some more human-readable format (ideally, an IR
391 // even), as this should be a great debugging aid.
392 pub fn dump(&self, db: &dyn DefDatabase) -> String {
393 let mut buf = String::new();
395 let mut current_map = self;
396 while let Some(block) = ¤t_map.block {
397 go(&mut buf, current_map, "block scope", current_map.root);
399 arc = block.parent.def_map(db);
402 go(&mut buf, current_map, "crate", current_map.root);
405 fn go(buf: &mut String, map: &DefMap, path: &str, module: LocalModuleId) {
406 format_to!(buf, "{}\n", path);
408 map.modules[module].scope.dump(buf);
410 for (name, child) in map.modules[module].children.iter() {
411 let path = format!("{}::{}", path, name);
413 go(buf, map, &path, *child);
418 pub fn dump_block_scopes(&self, db: &dyn DefDatabase) -> String {
419 let mut buf = String::new();
421 let mut current_map = self;
422 while let Some(block) = ¤t_map.block {
423 format_to!(buf, "{:?} in {:?}\n", block.block, block.parent);
424 arc = block.parent.def_map(db);
428 format_to!(buf, "crate scope\n");
432 fn shrink_to_fit(&mut self) {
433 // Exhaustive match to require handling new fields.
436 exported_proc_macros,
447 extern_prelude.shrink_to_fit();
448 exported_proc_macros.shrink_to_fit();
449 diagnostics.shrink_to_fit();
450 modules.shrink_to_fit();
451 for (_, module) in modules.iter_mut() {
452 module.children.shrink_to_fit();
453 module.scope.shrink_to_fit();
457 /// Get a reference to the def map's diagnostics.
458 pub fn diagnostics(&self) -> &[DefDiagnostic] {
459 self.diagnostics.as_slice()
464 pub(crate) fn new(origin: ModuleOrigin, visibility: Visibility) -> Self {
469 children: FxHashMap::default(),
470 scope: ItemScope::default(),
474 /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
475 pub fn definition_source(&self, db: &dyn DefDatabase) -> InFile<ModuleSource> {
476 self.origin.definition_source(db)
479 /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
480 /// `None` for the crate root or block.
481 pub fn declaration_source(&self, db: &dyn DefDatabase) -> Option<InFile<ast::Module>> {
482 let decl = self.origin.declaration()?;
483 let value = decl.to_node(db.upcast());
484 Some(InFile { file_id: decl.file_id, value })
488 #[derive(Debug, Clone, PartialEq, Eq)]
489 pub enum ModuleSource {
490 SourceFile(ast::SourceFile),
492 BlockExpr(ast::BlockExpr),