Mostly restore hir API boundary

crates/hir/src/lib.rs

@@ -28,6 +28,7 @@ mod has_source;
 
 pub mod diagnostics;
 pub mod db;
+pub mod symbols;
 
 mod display;
 
@@ -40,12 +41,16 @@ use hir_def::{
     adt::{ReprKind, VariantData},
     body::{BodyDiagnostic, SyntheticSyntax},
     expr::{BindingAnnotation, LabelId, Pat, PatId},
+    item_tree::ItemTreeNode,
     lang_item::LangItemTarget,
     nameres::{self, diagnostics::DefDiagnostic},
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
-    AttrDefId, ConstId, ConstParamId, EnumId, FunctionId, GenericDefId, HasModule, LifetimeParamId,
+    src::HasSource as _,
-    LocalEnumVariantId, LocalFieldId, StaticId, StructId, TypeAliasId, TypeParamId, UnionId,
+    AdtId, AssocItemId, AssocItemLoc, AttrDefId, ConstId, ConstParamId, DefWithBodyId, EnumId,
+    FunctionId, GenericDefId, HasModule, ImplId, ItemContainerId, LifetimeParamId,
+    LocalEnumVariantId, LocalFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId,
+    TypeParamId, UnionId,
 };
 use hir_expand::{name::name, MacroCallKind, MacroDefKind};
 use hir_ty::{
@@ -106,24 +111,11 @@ pub use {
         builtin_attr::AttributeTemplate,
         find_path::PrefixKind,
         import_map,
-        item_scope::ItemScope,
+        nameres::ModuleSource,
-        item_tree::ItemTreeNode,
-        nameres::{DefMap, ModuleData, ModuleOrigin, ModuleSource},
         path::{ModPath, PathKind},
-        src::HasSource as DefHasSource, // xx: I don't like this shadowing of HasSource... :(
         type_ref::{Mutability, TypeRef},
         visibility::Visibility,
-        AdtId,
-        AssocItemId,
-        AssocItemLoc,
-        DefWithBodyId,
-        ImplId,
-        ItemContainerId,
-        ItemLoc,
-        Lookup,
-        ModuleDefId,
         ModuleId,
-        TraitId,
     },
     hir_expand::{
         name::{known, Name},

crates/hir/src/symbols.rs

@@ -0,0 +1,359 @@
+//! File symbol extraction.
+
+use base_db::FileRange;
+use either::Either;
+use hir_def::{
+    item_tree::ItemTreeNode, src::HasSource, AdtId, AssocItemId, AssocItemLoc, DefWithBodyId,
+    ImplId, ItemContainerId, ItemLoc, Lookup, ModuleDefId, ModuleId, TraitId,
+};
+use hir_expand::{HirFileId, InFile};
+use hir_ty::db::HirDatabase;
+use syntax::{ast::HasName, AstNode, SmolStr, SyntaxNode, SyntaxNodePtr};
+
+use crate::{HasSource as _, MacroDef, Module, Semantics};
+
+/// The actual data that is stored in the index. It should be as compact as
+/// possible.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct FileSymbol {
+    pub name: SmolStr,
+    pub loc: DeclarationLocation,
+    pub kind: FileSymbolKind,
+    pub container_name: Option<SmolStr>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct DeclarationLocation {
+    /// The file id for both the `ptr` and `name_ptr`.
+    pub hir_file_id: HirFileId,
+    /// This points to the whole syntax node of the declaration.
+    pub ptr: SyntaxNodePtr,
+    /// This points to the [`syntax::ast::Name`] identifier of the declaration.
+    pub name_ptr: SyntaxNodePtr,
+}
+
+impl DeclarationLocation {
+    pub fn syntax<DB: HirDatabase>(&self, sema: &Semantics<DB>) -> Option<SyntaxNode> {
+        let root = sema.parse_or_expand(self.hir_file_id)?;
+        Some(self.ptr.to_node(&root))
+    }
+
+    pub fn original_range(&self, db: &dyn HirDatabase) -> Option<FileRange> {
+        find_original_file_range(db, self.hir_file_id, &self.ptr)
+    }
+
+    pub fn original_name_range(&self, db: &dyn HirDatabase) -> Option<FileRange> {
+        find_original_file_range(db, self.hir_file_id, &self.name_ptr)
+    }
+}
+
+fn find_original_file_range(
+    db: &dyn HirDatabase,
+    file_id: HirFileId,
+    ptr: &SyntaxNodePtr,
+) -> Option<FileRange> {
+    let root = db.parse_or_expand(file_id)?;
+    let node = ptr.to_node(&root);
+    let node = InFile::new(file_id, &node);
+
+    Some(node.original_file_range(db.upcast()))
+}
+
+#[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
+pub enum FileSymbolKind {
+    Const,
+    Enum,
+    Function,
+    Macro,
+    Module,
+    Static,
+    Struct,
+    Trait,
+    TypeAlias,
+    Union,
+}
+
+impl FileSymbolKind {
+    pub fn is_type(self: FileSymbolKind) -> bool {
+        matches!(
+            self,
+            FileSymbolKind::Struct
+                | FileSymbolKind::Enum
+                | FileSymbolKind::Trait
+                | FileSymbolKind::TypeAlias
+                | FileSymbolKind::Union
+        )
+    }
+}
+
+/// Represents an outstanding module that the symbol collector must collect symbols from.
+struct SymbolCollectorWork {
+    module_id: ModuleId,
+    parent: Option<DefWithBodyId>,
+}
+
+pub struct SymbolCollector<'a> {
+    db: &'a dyn HirDatabase,
+    symbols: Vec<FileSymbol>,
+    work: Vec<SymbolCollectorWork>,
+    current_container_name: Option<SmolStr>,
+}
+
+/// Given a [`ModuleId`] and a [`HirDatabase`], use the DefMap for the module's crate to collect
+/// all symbols that should be indexed for the given module.
+impl<'a> SymbolCollector<'a> {
+    pub fn collect(db: &dyn HirDatabase, module_id: ModuleId) -> Vec<FileSymbol> {
+        let mut symbol_collector = SymbolCollector {
+            db,
+            symbols: Default::default(),
+            current_container_name: None,
+            // The initial work is the root module we're collecting, additional work will
+            // be populated as we traverse the module's definitions.
+            work: vec![SymbolCollectorWork { module_id, parent: None }],
+        };
+
+        while let Some(work) = symbol_collector.work.pop() {
+            symbol_collector.do_work(work);
+        }
+
+        symbol_collector.symbols
+    }
+
+    fn do_work(&mut self, work: SymbolCollectorWork) {
+        self.db.unwind_if_cancelled();
+
+        let parent_name = work.parent.and_then(|id| self.def_with_body_id_name(id));
+        self.with_container_name(parent_name, |s| s.collect_from_module(work.module_id));
+    }
+
+    fn collect_from_module(&mut self, module_id: ModuleId) {
+        let def_map = module_id.def_map(self.db.upcast());
+        let scope = &def_map[module_id.local_id].scope;
+
+        for module_def_id in scope.declarations() {
+            match module_def_id {
+                ModuleDefId::ModuleId(id) => self.push_module(id),
+                ModuleDefId::FunctionId(id) => {
+                    self.push_decl_assoc(id, FileSymbolKind::Function);
+                    self.collect_from_body(id);
+                }
+                ModuleDefId::AdtId(AdtId::StructId(id)) => {
+                    self.push_decl(id, FileSymbolKind::Struct)
+                }
+                ModuleDefId::AdtId(AdtId::EnumId(id)) => self.push_decl(id, FileSymbolKind::Enum),
+                ModuleDefId::AdtId(AdtId::UnionId(id)) => self.push_decl(id, FileSymbolKind::Union),
+                ModuleDefId::ConstId(id) => {
+                    self.push_decl_assoc(id, FileSymbolKind::Const);
+                    self.collect_from_body(id);
+                }
+                ModuleDefId::StaticId(id) => {
+                    self.push_decl_assoc(id, FileSymbolKind::Static);
+                    self.collect_from_body(id);
+                }
+                ModuleDefId::TraitId(id) => {
+                    self.push_decl(id, FileSymbolKind::Trait);
+                    self.collect_from_trait(id);
+                }
+                ModuleDefId::TypeAliasId(id) => {
+                    self.push_decl_assoc(id, FileSymbolKind::TypeAlias);
+                }
+                // Don't index these.
+                ModuleDefId::BuiltinType(_) => {}
+                ModuleDefId::EnumVariantId(_) => {}
+            }
+        }
+
+        for impl_id in scope.impls() {
+            self.collect_from_impl(impl_id);
+        }
+
+        for const_id in scope.unnamed_consts() {
+            self.collect_from_body(const_id);
+        }
+
+        for macro_def_id in scope.macro_declarations() {
+            self.push_decl_macro(macro_def_id.into());
+        }
+    }
+
+    fn collect_from_body(&mut self, body_id: impl Into<DefWithBodyId>) {
+        let body_id = body_id.into();
+        let body = self.db.body(body_id);
+
+        // Descend into the blocks and enqueue collection of all modules within.
+        for (_, def_map) in body.blocks(self.db.upcast()) {
+            for (id, _) in def_map.modules() {
+                self.work.push(SymbolCollectorWork {
+                    module_id: def_map.module_id(id),
+                    parent: Some(body_id),
+                });
+            }
+        }
+    }
+
+    fn collect_from_impl(&mut self, impl_id: ImplId) {
+        let impl_data = self.db.impl_data(impl_id);
+        for &assoc_item_id in &impl_data.items {
+            self.push_assoc_item(assoc_item_id)
+        }
+    }
+
+    fn collect_from_trait(&mut self, trait_id: TraitId) {
+        let trait_data = self.db.trait_data(trait_id);
+        self.with_container_name(trait_data.name.as_text(), |s| {
+            for &(_, assoc_item_id) in &trait_data.items {
+                s.push_assoc_item(assoc_item_id);
+            }
+        });
+    }
+
+    fn with_container_name(&mut self, container_name: Option<SmolStr>, f: impl FnOnce(&mut Self)) {
+        if let Some(container_name) = container_name {
+            let prev = self.current_container_name.replace(container_name);
+            f(self);
+            self.current_container_name = prev;
+        } else {
+            f(self);
+        }
+    }
+
+    fn current_container_name(&self) -> Option<SmolStr> {
+        self.current_container_name.clone()
+    }
+
+    fn def_with_body_id_name(&self, body_id: DefWithBodyId) -> Option<SmolStr> {
+        match body_id {
+            DefWithBodyId::FunctionId(id) => Some(
+                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
+            ),
+            DefWithBodyId::StaticId(id) => Some(
+                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
+            ),
+            DefWithBodyId::ConstId(id) => Some(
+                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
+            ),
+        }
+    }
+
+    fn push_assoc_item(&mut self, assoc_item_id: AssocItemId) {
+        match assoc_item_id {
+            AssocItemId::FunctionId(id) => self.push_decl_assoc(id, FileSymbolKind::Function),
+            AssocItemId::ConstId(id) => self.push_decl_assoc(id, FileSymbolKind::Const),
+            AssocItemId::TypeAliasId(id) => self.push_decl_assoc(id, FileSymbolKind::TypeAlias),
+        }
+    }
+
+    fn push_decl_assoc<L, T>(&mut self, id: L, kind: FileSymbolKind)
+    where
+        L: Lookup<Data = AssocItemLoc<T>>,
+        T: ItemTreeNode,
+        <T as ItemTreeNode>::Source: HasName,
+    {
+        fn container_name(db: &dyn HirDatabase, container: ItemContainerId) -> Option<SmolStr> {
+            match container {
+                ItemContainerId::ModuleId(module_id) => {
+                    let module = Module::from(module_id);
+                    module.name(db).and_then(|name| name.as_text())
+                }
+                ItemContainerId::TraitId(trait_id) => {
+                    let trait_data = db.trait_data(trait_id);
+                    trait_data.name.as_text()
+                }
+                ItemContainerId::ImplId(_) | ItemContainerId::ExternBlockId(_) => None,
+            }
+        }
+
+        self.push_file_symbol(|s| {
+            let loc = id.lookup(s.db.upcast());
+            let source = loc.source(s.db.upcast());
+            let name_node = source.value.name()?;
+            let container_name =
+                container_name(s.db, loc.container).or_else(|| s.current_container_name());
+
+            Some(FileSymbol {
+                name: name_node.text().into(),
+                kind,
+                container_name,
+                loc: DeclarationLocation {
+                    hir_file_id: source.file_id,
+                    ptr: SyntaxNodePtr::new(source.value.syntax()),
+                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
+                },
+            })
+        })
+    }
+
+    fn push_decl<L, T>(&mut self, id: L, kind: FileSymbolKind)
+    where
+        L: Lookup<Data = ItemLoc<T>>,
+        T: ItemTreeNode,
+        <T as ItemTreeNode>::Source: HasName,
+    {
+        self.push_file_symbol(|s| {
+            let loc = id.lookup(s.db.upcast());
+            let source = loc.source(s.db.upcast());
+            let name_node = source.value.name()?;
+
+            Some(FileSymbol {
+                name: name_node.text().into(),
+                kind,
+                container_name: s.current_container_name(),
+                loc: DeclarationLocation {
+                    hir_file_id: source.file_id,
+                    ptr: SyntaxNodePtr::new(source.value.syntax()),
+                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
+                },
+            })
+        })
+    }
+
+    fn push_module(&mut self, module_id: ModuleId) {
+        self.push_file_symbol(|s| {
+            let def_map = module_id.def_map(s.db.upcast());
+            let module_data = &def_map[module_id.local_id];
+            let declaration = module_data.origin.declaration()?;
+            let module = declaration.to_node(s.db.upcast());
+            let name_node = module.name()?;
+
+            Some(FileSymbol {
+                name: name_node.text().into(),
+                kind: FileSymbolKind::Module,
+                container_name: s.current_container_name(),
+                loc: DeclarationLocation {
+                    hir_file_id: declaration.file_id,
+                    ptr: SyntaxNodePtr::new(module.syntax()),
+                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
+                },
+            })
+        })
+    }
+
+    fn push_decl_macro(&mut self, macro_def: MacroDef) {
+        self.push_file_symbol(|s| {
+            let name = macro_def.name(s.db)?.as_text()?;
+            let source = macro_def.source(s.db)?;
+
+            let (ptr, name_ptr) = match source.value {
+                Either::Left(m) => {
+                    (SyntaxNodePtr::new(m.syntax()), SyntaxNodePtr::new(m.name()?.syntax()))
+                }
+                Either::Right(f) => {
+                    (SyntaxNodePtr::new(f.syntax()), SyntaxNodePtr::new(f.name()?.syntax()))
+                }
+            };
+
+            Some(FileSymbol {
+                name,
+                kind: FileSymbolKind::Macro,
+                container_name: s.current_container_name(),
+                loc: DeclarationLocation { hir_file_id: source.file_id, name_ptr, ptr },
+            })
+        })
+    }
+
+    fn push_file_symbol(&mut self, f: impl FnOnce(&Self) -> Option<FileSymbol>) {
+        if let Some(file_symbol) = f(self) {
+            self.symbols.push(file_symbol);
+        }
+    }
+}

crates/ide/src/lib.rs

@@ -66,8 +66,7 @@ use ide_db::{
         salsa::{self, ParallelDatabase},
         Env, FileLoader, FileSet, SourceDatabase, VfsPath,
     },
-    symbol_index::{self, FileSymbol},
+    symbol_index, LineIndexDatabase,
-    LineIndexDatabase,
 };
 use syntax::SourceFile;
 

crates/ide/src/navigation_target.rs

@@ -4,8 +4,8 @@ use std::fmt;
 
 use either::Either;
 use hir::{
-    AssocItem, Documentation, FieldSource, HasAttrs, HasSource, HirDisplay, InFile, ModuleSource,
+    symbols::FileSymbol, AssocItem, Documentation, FieldSource, HasAttrs, HasSource, HirDisplay,
-    Semantics,
+    InFile, ModuleSource, Semantics,
 };
 use ide_db::{
     base_db::{FileId, FileRange},
@@ -17,8 +17,6 @@ use syntax::{
     match_ast, AstNode, SmolStr, TextRange,
 };
 
-use crate::FileSymbol;
-
 /// `NavigationTarget` represents an element in the editor's UI which you can
 /// click on to navigate to a particular piece of code.
 ///

crates/ide_db/src/items_locator.rs

@@ -5,6 +5,7 @@
 use either::Either;
 use hir::{
     import_map::{self, ImportKind},
+    symbols::FileSymbol,
     AsAssocItem, Crate, ItemInNs, Semantics,
 };
 use limit::Limit;
@@ -13,8 +14,7 @@ use syntax::{ast, AstNode, SyntaxKind::NAME};
 use crate::{
     defs::{Definition, NameClass},
     helpers::import_assets::NameToImport,
-    symbol_index::{self, FileSymbol},
+    symbol_index, RootDatabase,
-    RootDatabase,
 };
 
 /// A value to use, when uncertain which limit to pick.

crates/ide_db/src/lib.rs

@@ -26,7 +26,10 @@ use base_db::{
     salsa::{self, Durability},
     AnchoredPath, CrateId, FileId, FileLoader, FileLoaderDelegate, SourceDatabase, Upcast,
 };
-use hir::db::{AstDatabase, DefDatabase, HirDatabase};
+use hir::{
+    db::{AstDatabase, DefDatabase, HirDatabase},
+    symbols::FileSymbolKind,
+};
 use rustc_hash::FxHashSet;
 
 use crate::{line_index::LineIndex, symbol_index::SymbolsDatabase};
@@ -183,6 +186,23 @@ impl From<hir::MacroKind> for SymbolKind {
     }
 }
 
+impl From<FileSymbolKind> for SymbolKind {
+    fn from(it: FileSymbolKind) -> Self {
+        match it {
+            FileSymbolKind::Const => SymbolKind::Const,
+            FileSymbolKind::Enum => SymbolKind::Enum,
+            FileSymbolKind::Function => SymbolKind::Function,
+            FileSymbolKind::Macro => SymbolKind::Macro,
+            FileSymbolKind::Module => SymbolKind::Module,
+            FileSymbolKind::Static => SymbolKind::Static,
+            FileSymbolKind::Struct => SymbolKind::Struct,
+            FileSymbolKind::Trait => SymbolKind::Trait,
+            FileSymbolKind::TypeAlias => SymbolKind::TypeAlias,
+            FileSymbolKind::Union => SymbolKind::Union,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     mod sourcegen_lints;

crates/ide_db/src/symbol_index.rs

@@ -30,21 +30,18 @@ use std::{
 
 use base_db::{
     salsa::{self, ParallelDatabase},
-    CrateId, FileRange, SourceDatabaseExt, SourceRootId, Upcast,
+    CrateId, SourceDatabaseExt, SourceRootId, Upcast,
 };
-use either::Either;
 use fst::{self, Streamer};
 use hir::{
     db::{DefDatabase, HirDatabase},
-    AdtId, AssocItemId, AssocItemLoc, DefHasSource, DefWithBodyId, HasSource, HirFileId, ImplId,
+    symbols::{FileSymbol, SymbolCollector},
-    InFile, ItemContainerId, ItemLoc, ItemTreeNode, Lookup, MacroDef, Module, ModuleDefId,
+    ModuleId,
-    ModuleId, Semantics, TraitId,
 };
 use rayon::prelude::*;
 use rustc_hash::FxHashSet;
-use syntax::{ast::HasName, AstNode, SmolStr, SyntaxNode, SyntaxNodePtr};
 
-use crate::{RootDatabase, SymbolKind};
+use crate::RootDatabase;
 
 #[derive(Debug)]
 pub struct Query {
@@ -123,7 +120,7 @@ fn library_symbols(db: &dyn SymbolsDatabase, source_root_id: SourceRootId) -> Ar
         // we specifically avoid calling SymbolsDatabase::module_symbols here, even they do the same thing,
         // as the index for a library is not going to really ever change, and we do not want to store each
         // module's index in salsa.
-        .map(|module_id| SymbolCollector::collect(db, module_id))
+        .map(|module_id| SymbolCollector::collect(db.upcast(), module_id))
         .flatten()
         .collect();
 
@@ -132,7 +129,7 @@ fn library_symbols(db: &dyn SymbolsDatabase, source_root_id: SourceRootId) -> Ar
 
 fn module_symbols(db: &dyn SymbolsDatabase, module_id: ModuleId) -> Arc<SymbolIndex> {
     let _p = profile::span("module_symbols");
-    let symbols = SymbolCollector::collect(db, module_id);
+    let symbols = SymbolCollector::collect(db.upcast(), module_id);
     Arc::new(SymbolIndex::new(symbols))
 }
 
@@ -356,374 +353,12 @@ impl Query {
     }
 }
 
-/// The actual data that is stored in the index. It should be as compact as
-/// possible.
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct FileSymbol {
-    pub name: SmolStr,
-    pub loc: DeclarationLocation,
-    pub kind: FileSymbolKind,
-    pub container_name: Option<SmolStr>,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct DeclarationLocation {
-    /// The file id for both the `ptr` and `name_ptr`.
-    pub hir_file_id: HirFileId,
-    /// This points to the whole syntax node of the declaration.
-    pub ptr: SyntaxNodePtr,
-    /// This points to the [`syntax::ast::Name`] identifier of the declaration.
-    pub name_ptr: SyntaxNodePtr,
-}
-
-impl DeclarationLocation {
-    pub fn syntax(&self, semantics: &Semantics<'_, RootDatabase>) -> Option<SyntaxNode> {
-        let root = semantics.parse_or_expand(self.hir_file_id)?;
-        Some(self.ptr.to_node(&root))
-    }
-
-    pub fn original_range(&self, db: &dyn HirDatabase) -> Option<FileRange> {
-        find_original_file_range(db, self.hir_file_id, &self.ptr)
-    }
-
-    pub fn original_name_range(&self, db: &dyn HirDatabase) -> Option<FileRange> {
-        find_original_file_range(db, self.hir_file_id, &self.name_ptr)
-    }
-}
-
-fn find_original_file_range(
-    db: &dyn HirDatabase,
-    file_id: HirFileId,
-    ptr: &SyntaxNodePtr,
-) -> Option<FileRange> {
-    let root = db.parse_or_expand(file_id)?;
-    let node = ptr.to_node(&root);
-    let node = InFile::new(file_id, &node);
-
-    Some(node.original_file_range(db.upcast()))
-}
-
-#[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
-pub enum FileSymbolKind {
-    Const,
-    Enum,
-    Function,
-    Macro,
-    Module,
-    Static,
-    Struct,
-    Trait,
-    TypeAlias,
-    Union,
-}
-
-impl FileSymbolKind {
-    fn is_type(self: FileSymbolKind) -> bool {
-        matches!(
-            self,
-            FileSymbolKind::Struct
-                | FileSymbolKind::Enum
-                | FileSymbolKind::Trait
-                | FileSymbolKind::TypeAlias
-                | FileSymbolKind::Union
-        )
-    }
-}
-
-impl From<FileSymbolKind> for SymbolKind {
-    fn from(it: FileSymbolKind) -> Self {
-        match it {
-            FileSymbolKind::Const => SymbolKind::Const,
-            FileSymbolKind::Enum => SymbolKind::Enum,
-            FileSymbolKind::Function => SymbolKind::Function,
-            FileSymbolKind::Macro => SymbolKind::Macro,
-            FileSymbolKind::Module => SymbolKind::Module,
-            FileSymbolKind::Static => SymbolKind::Static,
-            FileSymbolKind::Struct => SymbolKind::Struct,
-            FileSymbolKind::Trait => SymbolKind::Trait,
-            FileSymbolKind::TypeAlias => SymbolKind::TypeAlias,
-            FileSymbolKind::Union => SymbolKind::Union,
-        }
-    }
-}
-
-/// Represents an outstanding module that the symbol collector must collect symbols from.
-struct SymbolCollectorWork {
-    module_id: ModuleId,
-    parent: Option<DefWithBodyId>,
-}
-
-struct SymbolCollector<'a> {
-    db: &'a dyn SymbolsDatabase,
-    symbols: Vec<FileSymbol>,
-    work: Vec<SymbolCollectorWork>,
-    current_container_name: Option<SmolStr>,
-}
-
-/// Given a [`ModuleId`] and a [`SymbolsDatabase`], use the DefMap for the module's crate to collect all symbols that should be
-/// indexed for the given module.
-impl<'a> SymbolCollector<'a> {
-    fn collect(db: &dyn SymbolsDatabase, module_id: ModuleId) -> Vec<FileSymbol> {
-        let mut symbol_collector = SymbolCollector {
-            db,
-            symbols: Default::default(),
-            current_container_name: None,
-            // The initial work is the root module we're collecting, additional work will
-            // be populated as we traverse the module's definitions.
-            work: vec![SymbolCollectorWork { module_id, parent: None }],
-        };
-
-        while let Some(work) = symbol_collector.work.pop() {
-            symbol_collector.do_work(work);
-        }
-
-        symbol_collector.symbols
-    }
-
-    fn do_work(&mut self, work: SymbolCollectorWork) {
-        self.db.unwind_if_cancelled();
-
-        let parent_name = work.parent.and_then(|id| self.def_with_body_id_name(id));
-        self.with_container_name(parent_name, |s| s.collect_from_module(work.module_id));
-    }
-
-    fn collect_from_module(&mut self, module_id: ModuleId) {
-        let def_map = module_id.def_map(self.db.upcast());
-        let scope = &def_map[module_id.local_id].scope;
-
-        for module_def_id in scope.declarations() {
-            match module_def_id {
-                ModuleDefId::ModuleId(id) => self.push_module(id),
-                ModuleDefId::FunctionId(id) => {
-                    self.push_decl_assoc(id, FileSymbolKind::Function);
-                    self.collect_from_body(id);
-                }
-                ModuleDefId::AdtId(AdtId::StructId(id)) => {
-                    self.push_decl(id, FileSymbolKind::Struct)
-                }
-                ModuleDefId::AdtId(AdtId::EnumId(id)) => self.push_decl(id, FileSymbolKind::Enum),
-                ModuleDefId::AdtId(AdtId::UnionId(id)) => self.push_decl(id, FileSymbolKind::Union),
-                ModuleDefId::ConstId(id) => {
-                    self.push_decl_assoc(id, FileSymbolKind::Const);
-                    self.collect_from_body(id);
-                }
-                ModuleDefId::StaticId(id) => {
-                    self.push_decl_assoc(id, FileSymbolKind::Static);
-                    self.collect_from_body(id);
-                }
-                ModuleDefId::TraitId(id) => {
-                    self.push_decl(id, FileSymbolKind::Trait);
-                    self.collect_from_trait(id);
-                }
-                ModuleDefId::TypeAliasId(id) => {
-                    self.push_decl_assoc(id, FileSymbolKind::TypeAlias);
-                }
-                // Don't index these.
-                ModuleDefId::BuiltinType(_) => {}
-                ModuleDefId::EnumVariantId(_) => {}
-            }
-        }
-
-        for impl_id in scope.impls() {
-            self.collect_from_impl(impl_id);
-        }
-
-        for const_id in scope.unnamed_consts() {
-            self.collect_from_body(const_id);
-        }
-
-        for macro_def_id in scope.macro_declarations() {
-            self.push_decl_macro(macro_def_id.into());
-        }
-    }
-
-    fn collect_from_body(&mut self, body_id: impl Into<DefWithBodyId>) {
-        let body_id = body_id.into();
-        let body = self.db.body(body_id);
-
-        // Descend into the blocks and enqueue collection of all modules within.
-        for (_, def_map) in body.blocks(self.db.upcast()) {
-            for (id, _) in def_map.modules() {
-                self.work.push(SymbolCollectorWork {
-                    module_id: def_map.module_id(id),
-                    parent: Some(body_id),
-                });
-            }
-        }
-    }
-
-    fn collect_from_impl(&mut self, impl_id: ImplId) {
-        let impl_data = self.db.impl_data(impl_id);
-        for &assoc_item_id in &impl_data.items {
-            self.push_assoc_item(assoc_item_id)
-        }
-    }
-
-    fn collect_from_trait(&mut self, trait_id: TraitId) {
-        let trait_data = self.db.trait_data(trait_id);
-        self.with_container_name(trait_data.name.as_text(), |s| {
-            for &(_, assoc_item_id) in &trait_data.items {
-                s.push_assoc_item(assoc_item_id);
-            }
-        });
-    }
-
-    fn with_container_name(&mut self, container_name: Option<SmolStr>, f: impl FnOnce(&mut Self)) {
-        if let Some(container_name) = container_name {
-            let prev = self.current_container_name.replace(container_name);
-            f(self);
-            self.current_container_name = prev;
-        } else {
-            f(self);
-        }
-    }
-
-    fn current_container_name(&self) -> Option<SmolStr> {
-        self.current_container_name.clone()
-    }
-
-    fn def_with_body_id_name(&self, body_id: DefWithBodyId) -> Option<SmolStr> {
-        match body_id {
-            DefWithBodyId::FunctionId(id) => Some(
-                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
-            ),
-            DefWithBodyId::StaticId(id) => Some(
-                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
-            ),
-            DefWithBodyId::ConstId(id) => Some(
-                id.lookup(self.db.upcast()).source(self.db.upcast()).value.name()?.text().into(),
-            ),
-        }
-    }
-
-    fn push_assoc_item(&mut self, assoc_item_id: AssocItemId) {
-        match assoc_item_id {
-            AssocItemId::FunctionId(id) => self.push_decl_assoc(id, FileSymbolKind::Function),
-            AssocItemId::ConstId(id) => self.push_decl_assoc(id, FileSymbolKind::Const),
-            AssocItemId::TypeAliasId(id) => self.push_decl_assoc(id, FileSymbolKind::TypeAlias),
-        }
-    }
-
-    fn push_decl_assoc<L, T>(&mut self, id: L, kind: FileSymbolKind)
-    where
-        L: Lookup<Data = AssocItemLoc<T>>,
-        T: ItemTreeNode,
-        <T as ItemTreeNode>::Source: HasName,
-    {
-        fn container_name(db: &dyn HirDatabase, container: ItemContainerId) -> Option<SmolStr> {
-            match container {
-                ItemContainerId::ModuleId(module_id) => {
-                    let module = Module::from(module_id);
-                    module.name(db).and_then(|name| name.as_text())
-                }
-                ItemContainerId::TraitId(trait_id) => {
-                    let trait_data = db.trait_data(trait_id);
-                    trait_data.name.as_text()
-                }
-                ItemContainerId::ImplId(_) | ItemContainerId::ExternBlockId(_) => None,
-            }
-        }
-
-        self.push_file_symbol(|s| {
-            let loc = id.lookup(s.db.upcast());
-            let source = loc.source(s.db.upcast());
-            let name_node = source.value.name()?;
-            let container_name =
-                container_name(s.db.upcast(), loc.container).or_else(|| s.current_container_name());
-
-            Some(FileSymbol {
-                name: name_node.text().into(),
-                kind,
-                container_name,
-                loc: DeclarationLocation {
-                    hir_file_id: source.file_id,
-                    ptr: SyntaxNodePtr::new(source.value.syntax()),
-                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
-                },
-            })
-        })
-    }
-
-    fn push_decl<L, T>(&mut self, id: L, kind: FileSymbolKind)
-    where
-        L: Lookup<Data = ItemLoc<T>>,
-        T: ItemTreeNode,
-        <T as ItemTreeNode>::Source: HasName,
-    {
-        self.push_file_symbol(|s| {
-            let loc = id.lookup(s.db.upcast());
-            let source = loc.source(s.db.upcast());
-            let name_node = source.value.name()?;
-
-            Some(FileSymbol {
-                name: name_node.text().into(),
-                kind,
-                container_name: s.current_container_name(),
-                loc: DeclarationLocation {
-                    hir_file_id: source.file_id,
-                    ptr: SyntaxNodePtr::new(source.value.syntax()),
-                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
-                },
-            })
-        })
-    }
-
-    fn push_module(&mut self, module_id: ModuleId) {
-        self.push_file_symbol(|s| {
-            let def_map = module_id.def_map(s.db.upcast());
-            let module_data = &def_map[module_id.local_id];
-            let declaration = module_data.origin.declaration()?;
-            let module = declaration.to_node(s.db.upcast());
-            let name_node = module.name()?;
-
-            Some(FileSymbol {
-                name: name_node.text().into(),
-                kind: FileSymbolKind::Module,
-                container_name: s.current_container_name(),
-                loc: DeclarationLocation {
-                    hir_file_id: declaration.file_id,
-                    ptr: SyntaxNodePtr::new(module.syntax()),
-                    name_ptr: SyntaxNodePtr::new(name_node.syntax()),
-                },
-            })
-        })
-    }
-
-    fn push_decl_macro(&mut self, macro_def: MacroDef) {
-        self.push_file_symbol(|s| {
-            let name = macro_def.name(s.db.upcast())?.as_text()?;
-            let source = macro_def.source(s.db.upcast())?;
-
-            let (ptr, name_ptr) = match source.value {
-                Either::Left(m) => {
-                    (SyntaxNodePtr::new(m.syntax()), SyntaxNodePtr::new(m.name()?.syntax()))
-                }
-                Either::Right(f) => {
-                    (SyntaxNodePtr::new(f.syntax()), SyntaxNodePtr::new(f.name()?.syntax()))
-                }
-            };
-
-            Some(FileSymbol {
-                name,
-                kind: FileSymbolKind::Macro,
-                container_name: s.current_container_name(),
-                loc: DeclarationLocation { hir_file_id: source.file_id, name_ptr, ptr },
-            })
-        })
-    }
-
-    fn push_file_symbol(&mut self, f: impl FnOnce(&Self) -> Option<FileSymbol>) {
-        if let Some(file_symbol) = f(self) {
-            self.symbols.push(file_symbol);
-        }
-    }
-}
-
 #[cfg(test)]
 mod tests {
 
     use base_db::fixture::WithFixture;
     use expect_test::expect_file;
+    use hir::symbols::SymbolCollector;
 
     use super::*;
 
@@ -794,9 +429,7 @@ struct StructInModB;
 
         let symbols: Vec<_> = module_ids_for_crate(db.upcast(), db.test_crate())
             .into_iter()
-            .map(|module_id| {
+            .map(|module_id| (module_id, SymbolCollector::collect(&db, module_id)))
-                (module_id, SymbolCollector::collect(&db as &dyn SymbolsDatabase, module_id))
-            })
             .collect();
 
         expect_file!["./test_data/test_symbol_index_collection.txt"].assert_debug_eq(&symbols);