Merge #247

247: Hir r=matklad a=matklad

This doesn't achive anything new, just a big refactoring. 

The main change is that Descriptors are now called `hir`, and live in a separate crate.

Co-authored-by: Aleksey Kladov <[email protected]>

30 files changed, 1249 insertions, 1060 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b4d466fb6..bacea8dc3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -604,10 +604,11 @@ name = "ra_analysis"
 version = "0.1.0"
 dependencies = [
  "fst 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "id-arena 1.0.2 (git+https://github.com/fitzgen/id-arena/?rev=43ecd67)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ra_db 0.1.0",
  "ra_editor 0.1.0",
+ "ra_hir 0.1.0",
  "ra_syntax 0.1.0",
  "rayon 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -629,6 +630,21 @@ dependencies = [
 ]
 
 [[package]]
+name = "ra_db"
+version = "0.1.0"
+dependencies = [
+ "id-arena 1.0.2 (git+https://github.com/fitzgen/id-arena/?rev=43ecd67)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ra_editor 0.1.0",
+ "ra_syntax 0.1.0",
+ "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "salsa 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "test_utils 0.1.0",
+]
+
+[[package]]
 name = "ra_editor"
 version = "0.1.0"
 dependencies = [
@@ -641,6 +657,22 @@ dependencies = [
 ]
 
 [[package]]
+name = "ra_hir"
+version = "0.1.0"
+dependencies = [
+ "id-arena 1.0.2 (git+https://github.com/fitzgen/id-arena/?rev=43ecd67)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ra_db 0.1.0",
+ "ra_editor 0.1.0",
+ "ra_syntax 0.1.0",
+ "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "salsa 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "test_utils 0.1.0",
+]
+
+[[package]]
 name = "ra_lsp_server"
 version = "0.1.0"
 dependencies = [
diff --git a/crates/ra_analysis/Cargo.toml b/crates/ra_analysis/Cargo.toml
index 5dae45857..fe9765a66 100644
--- a/crates/ra_analysis/Cargo.toml
+++ b/crates/ra_analysis/Cargo.toml
@@ -12,7 +12,8 @@ fst = "0.3.1"
 salsa = "0.8.0"
 rustc-hash = "1.0"
 parking_lot = "0.6.4"
-id-arena = { git = "https://github.com/fitzgen/id-arena/", rev = "43ecd67" }
 ra_syntax = { path = "../ra_syntax" }
 ra_editor = { path = "../ra_editor" }
+ra_db = { path = "../ra_db" }
+hir = { path = "../ra_hir", package = "ra_hir" }
 test_utils = { path = "../test_utils" }
diff --git a/crates/ra_analysis/src/completion/mod.rs b/crates/ra_analysis/src/completion/mod.rs
index 5ef278127..e5ba92acd 100644
--- a/crates/ra_analysis/src/completion/mod.rs
+++ b/crates/ra_analysis/src/completion/mod.rs
@@ -7,13 +7,11 @@ use ra_syntax::{
     AstNode, AtomEdit,
     SyntaxNodeRef,
 };
+use ra_db::SyntaxDatabase;
 use rustc_hash::{FxHashMap};
 
 use crate::{
-    db::{self, SyntaxDatabase},
-    descriptors::{
-        module::{ModuleDescriptor}
-    },
+    db,
     Cancelable, FilePosition
 };
 
@@ -31,14 +29,14 @@ pub(crate) fn completions(
     db: &db::RootDatabase,
     position: FilePosition,
 ) -> Cancelable<Option<Vec<CompletionItem>>> {
-    let original_file = db.file_syntax(position.file_id);
+    let original_file = db.source_file(position.file_id);
     // Insert a fake ident to get a valid parse tree
     let file = {
         let edit = AtomEdit::insert(position.offset, "intellijRulezz".to_string());
         original_file.reparse(&edit)
     };
 
-    let module = ctry!(ModuleDescriptor::guess_from_position(db, position)?);
+    let module = ctry!(hir::Module::guess_from_position(db, position)?);
 
     let mut res = Vec::new();
     let mut has_completions = false;
diff --git a/crates/ra_analysis/src/completion/reference_completion.rs b/crates/ra_analysis/src/completion/reference_completion.rs
index 858b52e76..e1a2d5241 100644
--- a/crates/ra_analysis/src/completion/reference_completion.rs
+++ b/crates/ra_analysis/src/completion/reference_completion.rs
@@ -6,23 +6,23 @@ use ra_syntax::{
     ast::{self, LoopBodyOwner},
     SyntaxKind::*,
 };
+use     hir::{
+        self,
+        FnScopes,
+        Def,
+        Path,
+};
 
 use crate::{
     db::RootDatabase,
     completion::CompletionItem,
-    descriptors::{
-        module::{ModuleDescriptor},
-        function::FnScopes,
-        Def,
-        Path,
-    },
     Cancelable
 };
 
 pub(super) fn completions(
     acc: &mut Vec<CompletionItem>,
     db: &RootDatabase,
-    module: &ModuleDescriptor,
+    module: &hir::Module,
     file: &SourceFileNode,
     name_ref: ast::NameRef,
 ) -> Cancelable<()> {
@@ -150,7 +150,7 @@ fn complete_fn(name_ref: ast::NameRef, scopes: &FnScopes, acc: &mut Vec<Completi
 fn complete_path(
     acc: &mut Vec<CompletionItem>,
     db: &RootDatabase,
-    module: &ModuleDescriptor,
+    module: &hir::Module,
     mut path: Path,
 ) -> Cancelable<()> {
     if path.segments.is_empty() {
diff --git a/crates/ra_analysis/src/db.rs b/crates/ra_analysis/src/db.rs
index 4e34265fb..7fc3fe31b 100644
--- a/crates/ra_analysis/src/db.rs
+++ b/crates/ra_analysis/src/db.rs
@@ -1,17 +1,12 @@
 use std::sync::Arc;
 #[cfg(test)]
 use parking_lot::Mutex;
-use ra_editor::LineIndex;
-use ra_syntax::{SourceFileNode, SyntaxNode};
 use salsa::{self, Database};
+use ra_db::{LocationIntener, BaseDatabase};
+use hir::{self, DefId, DefLoc, FnId, SourceItemId};
 
 use crate::{
-    db,
-    descriptors,
-    symbol_index::SymbolIndex,
-    syntax_ptr::SyntaxPtr,
-    loc2id::{IdMaps, IdDatabase},
-    Cancelable, Canceled, FileId,
+    symbol_index,
 };
 
 #[derive(Debug)]
@@ -22,7 +17,13 @@ pub(crate) struct RootDatabase {
     events: (),
 
     runtime: salsa::Runtime<RootDatabase>,
-    id_maps: IdMaps,
+    id_maps: Arc<IdMaps>,
+}
+
+#[derive(Debug, Default)]
+struct IdMaps {
+    fns: LocationIntener<SourceItemId, FnId>,
+    defs: LocationIntener<DefLoc, DefId>,
 }
 
 impl salsa::Database for RootDatabase {
@@ -47,26 +48,18 @@ impl Default for RootDatabase {
         let mut db = RootDatabase {
             events: Default::default(),
             runtime: salsa::Runtime::default(),
-            id_maps: IdMaps::default(),
+            id_maps: Default::default(),
         };
-        db.query_mut(crate::input::SourceRootQuery)
-            .set(crate::input::WORKSPACE, Default::default());
-        db.query_mut(crate::input::CrateGraphQuery)
+        db.query_mut(ra_db::SourceRootQuery)
+            .set(ra_db::WORKSPACE, Default::default());
+        db.query_mut(ra_db::CrateGraphQuery)
             .set((), Default::default());
-        db.query_mut(crate::input::LibrariesQuery)
+        db.query_mut(ra_db::LibrariesQuery)
             .set((), Default::default());
         db
     }
 }
 
-pub(crate) fn check_canceled(db: &impl salsa::Database) -> Cancelable<()> {
-    if db.salsa_runtime().is_current_revision_canceled() {
-        Err(Canceled)
-    } else {
-        Ok(())
-    }
-}
-
 impl salsa::ParallelDatabase for RootDatabase {
     fn snapshot(&self) -> salsa::Snapshot<RootDatabase> {
         salsa::Snapshot::new(RootDatabase {
@@ -77,9 +70,17 @@ impl salsa::ParallelDatabase for RootDatabase {
     }
 }
 
-impl IdDatabase for RootDatabase {
-    fn id_maps(&self) -> &IdMaps {
-        &self.id_maps
+impl BaseDatabase for RootDatabase {}
+
+impl AsRef<LocationIntener<DefLoc, DefId>> for RootDatabase {
+    fn as_ref(&self) -> &LocationIntener<DefLoc, DefId> {
+        &self.id_maps.defs
+    }
+}
+
+impl AsRef<LocationIntener<hir::SourceItemId, FnId>> for RootDatabase {
+    fn as_ref(&self) -> &LocationIntener<hir::SourceItemId, FnId> {
+        &self.id_maps.fns
     }
 }
 
@@ -108,63 +109,30 @@ impl RootDatabase {
 
 salsa::database_storage! {
     pub(crate) struct RootDatabaseStorage for RootDatabase {
-        impl crate::input::FilesDatabase {
-            fn file_text() for crate::input::FileTextQuery;
-            fn file_source_root() for crate::input::FileSourceRootQuery;
-            fn source_root() for crate::input::SourceRootQuery;
-            fn libraries() for crate::input::LibrariesQuery;
-            fn library_symbols() for crate::input::LibrarySymbolsQuery;
-            fn crate_graph() for crate::input::CrateGraphQuery;
+        impl ra_db::FilesDatabase {
+            fn file_text() for ra_db::FileTextQuery;
+            fn file_source_root() for ra_db::FileSourceRootQuery;
+            fn source_root() for ra_db::SourceRootQuery;
+            fn libraries() for ra_db::LibrariesQuery;
+            fn crate_graph() for ra_db::CrateGraphQuery;
         }
-        impl SyntaxDatabase {
-            fn file_syntax() for FileSyntaxQuery;
-            fn file_lines() for FileLinesQuery;
-            fn file_symbols() for FileSymbolsQuery;
-            fn resolve_syntax_ptr() for ResolveSyntaxPtrQuery;
+        impl ra_db::SyntaxDatabase {
+            fn source_file() for ra_db::SourceFileQuery;
+            fn file_lines() for ra_db::FileLinesQuery;
         }
-        impl descriptors::DescriptorDatabase {
-            fn module_tree() for descriptors::ModuleTreeQuery;
-            fn fn_scopes() for descriptors::FnScopesQuery;
-            fn _file_items() for descriptors::FileItemsQuery;
-            fn _file_item() for descriptors::FileItemQuery;
-            fn _input_module_items() for descriptors::InputModuleItemsQuery;
-            fn _item_map() for descriptors::ItemMapQuery;
-            fn _fn_syntax() for descriptors::FnSyntaxQuery;
-            fn _submodules() for descriptors::SubmodulesQuery;
+        impl symbol_index::SymbolsDatabase {
+            fn file_symbols() for symbol_index::FileSymbolsQuery;
+            fn library_symbols() for symbol_index::LibrarySymbolsQuery;
         }
-    }
-}
-
-salsa::query_group! {
-    pub(crate) trait SyntaxDatabase: crate::input::FilesDatabase {
-        fn file_syntax(file_id: FileId) -> SourceFileNode {
-            type FileSyntaxQuery;
-        }
-        fn file_lines(file_id: FileId) -> Arc<LineIndex> {
-            type FileLinesQuery;
-        }
-        fn file_symbols(file_id: FileId) -> Cancelable<Arc<SymbolIndex>> {
-            type FileSymbolsQuery;
-        }
-        fn resolve_syntax_ptr(ptr: SyntaxPtr) -> SyntaxNode {
-            type ResolveSyntaxPtrQuery;
-            // Don't retain syntax trees in memory
-            storage dependencies;
-            use fn crate::syntax_ptr::resolve_syntax_ptr;
+        impl hir::db::HirDatabase {
+            fn module_tree() for hir::db::ModuleTreeQuery;
+            fn fn_scopes() for hir::db::FnScopesQuery;
+            fn file_items() for hir::db::SourceFileItemsQuery;
+            fn file_item() for hir::db::FileItemQuery;
+            fn input_module_items() for hir::db::InputModuleItemsQuery;
+            fn item_map() for hir::db::ItemMapQuery;
+            fn fn_syntax() for hir::db::FnSyntaxQuery;
+            fn submodules() for hir::db::SubmodulesQuery;
         }
     }
 }
-
-fn file_syntax(db: &impl SyntaxDatabase, file_id: FileId) -> SourceFileNode {
-    let text = db.file_text(file_id);
-    SourceFileNode::parse(&*text)
-}
-fn file_lines(db: &impl SyntaxDatabase, file_id: FileId) -> Arc<LineIndex> {
-    let text = db.file_text(file_id);
-    Arc::new(LineIndex::new(&*text))
-}
-fn file_symbols(db: &impl SyntaxDatabase, file_id: FileId) -> Cancelable<Arc<SymbolIndex>> {
-    db::check_canceled(db)?;
-    let syntax = db.file_syntax(file_id);
-    Ok(Arc::new(SymbolIndex::for_file(file_id, syntax)))
-}
diff --git a/crates/ra_analysis/src/descriptors/function/imp.rs b/crates/ra_analysis/src/descriptors/function/imp.rs
deleted file mode 100644
index e09deba0f..000000000
--- a/crates/ra_analysis/src/descriptors/function/imp.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-use std::sync::Arc;
-
-use ra_syntax::ast::{AstNode, FnDef, FnDefNode};
-
-use crate::descriptors::{
-    function::{FnId, FnScopes},
-    DescriptorDatabase,
-};
-
-/// Resolve `FnId` to the corresponding `SyntaxNode`
-pub(crate) fn fn_syntax(db: &impl DescriptorDatabase, fn_id: FnId) -> FnDefNode {
-    let ptr = db.id_maps().fn_ptr(fn_id);
-    let syntax = db.resolve_syntax_ptr(ptr);
-    FnDef::cast(syntax.borrowed()).unwrap().owned()
-}
-
-pub(crate) fn fn_scopes(db: &impl DescriptorDatabase, fn_id: FnId) -> Arc<FnScopes> {
-    let syntax = db._fn_syntax(fn_id);
-    let res = FnScopes::new(syntax.borrowed());
-    Arc::new(res)
-}
diff --git a/crates/ra_analysis/src/descriptors/mod.rs b/crates/ra_analysis/src/descriptors/mod.rs
deleted file mode 100644
index 7a1bcf447..000000000
--- a/crates/ra_analysis/src/descriptors/mod.rs
+++ /dev/null
@@ -1,137 +0,0 @@
-pub(crate) mod function;
-pub(crate) mod module;
-mod path;
-
-use std::sync::Arc;
-
-use ra_syntax::{
-    ast::{self, FnDefNode, AstNode},
-    TextRange, SyntaxNode,
-};
-
-use crate::{
-    FileId,
-    db::SyntaxDatabase,
-    descriptors::function::{resolve_local_name, FnId, FnScopes},
-    descriptors::module::{
-        ModuleId, ModuleTree, ModuleSource, ModuleDescriptor,
-        nameres::{ItemMap, InputModuleItems, FileItems}
-    },
-    input::SourceRootId,
-    loc2id::{IdDatabase, DefId, DefLoc},
-    syntax_ptr::LocalSyntaxPtr,
-    Cancelable,
-};
-
-pub(crate) use self::path::{Path, PathKind};
-pub(crate) use self::module::nameres::FileItemId;
-
-salsa::query_group! {
-    pub(crate) trait DescriptorDatabase: SyntaxDatabase + IdDatabase {
-        fn fn_scopes(fn_id: FnId) -> Arc<FnScopes> {
-            type FnScopesQuery;
-            use fn function::imp::fn_scopes;
-        }
-
-        fn _file_items(file_id: FileId) -> Arc<FileItems> {
-            type FileItemsQuery;
-            storage dependencies;
-            use fn module::nameres::file_items;
-        }
-
-        fn _file_item(file_id: FileId, file_item_id: FileItemId) -> SyntaxNode {
-            type FileItemQuery;
-            storage dependencies;
-            use fn module::nameres::file_item;
-        }
-
-        fn _input_module_items(source_root_id: SourceRootId, module_id: ModuleId) -> Cancelable<Arc<InputModuleItems>> {
-            type InputModuleItemsQuery;
-            use fn module::nameres::input_module_items;
-        }
-        fn _item_map(source_root_id: SourceRootId) -> Cancelable<Arc<ItemMap>> {
-            type ItemMapQuery;
-            use fn module::nameres::item_map;
-        }
-        fn _module_tree(source_root_id: SourceRootId) -> Cancelable<Arc<ModuleTree>> {
-            type ModuleTreeQuery;
-            use fn module::imp::module_tree;
-        }
-        fn _fn_syntax(fn_id: FnId) -> FnDefNode {
-            type FnSyntaxQuery;
-            // Don't retain syntax trees in memory
-            storage dependencies;
-            use fn function::imp::fn_syntax;
-        }
-        fn _submodules(source: ModuleSource) -> Cancelable<Arc<Vec<module::imp::Submodule>>> {
-            type SubmodulesQuery;
-            use fn module::imp::submodules;
-        }
-    }
-}
-
-pub(crate) enum Def {
-    Module(ModuleDescriptor),
-    Item,
-}
-
-impl DefId {
-    pub(crate) fn resolve(self, db: &impl DescriptorDatabase) -> Cancelable<Def> {
-        let loc = db.id_maps().def_loc(self);
-        let res = match loc {
-            DefLoc::Module { id, source_root } => {
-                let descr = ModuleDescriptor::new(db, source_root, id)?;
-                Def::Module(descr)
-            }
-            DefLoc::Item { .. } => Def::Item,
-        };
-        Ok(res)
-    }
-}
-
-#[derive(Debug)]
-pub struct ReferenceDescriptor {
-    pub range: TextRange,
-    pub name: String,
-}
-
-#[derive(Debug)]
-pub struct DeclarationDescriptor<'a> {
-    pat: ast::BindPat<'a>,
-    pub range: TextRange,
-}
-
-impl<'a> DeclarationDescriptor<'a> {
-    pub fn new(pat: ast::BindPat) -> DeclarationDescriptor {
-        let range = pat.syntax().range();
-
-        DeclarationDescriptor { pat, range }
-    }
-
-    pub fn find_all_refs(&self) -> Vec<ReferenceDescriptor> {
-        let name_ptr = LocalSyntaxPtr::new(self.pat.syntax());
-
-        let fn_def = match self.pat.syntax().ancestors().find_map(ast::FnDef::cast) {
-            Some(def) => def,
-            None => return Default::default(),
-        };
-
-        let fn_scopes = FnScopes::new(fn_def);
-
-        let refs: Vec<_> = fn_def
-            .syntax()
-            .descendants()
-            .filter_map(ast::NameRef::cast)
-            .filter(|name_ref| match resolve_local_name(*name_ref, &fn_scopes) {
-                None => false,
-                Some(entry) => entry.ptr() == name_ptr,
-            })
-            .map(|name_ref| ReferenceDescriptor {
-                name: name_ref.syntax().text().to_string(),
-                range: name_ref.syntax().range(),
-            })
-            .collect();
-
-        refs
-    }
-}
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index 8a41b3152..f5cb3550e 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -1,94 +1,33 @@
 use std::{
     fmt,
-    hash::{Hash, Hasher},
     sync::Arc,
 };
 
 use ra_editor::{self, find_node_at_offset, FileSymbol, LineIndex, LocalEdit};
 use ra_syntax::{
     ast::{self, ArgListOwner, Expr, NameOwner},
-    AstNode, SourceFileNode, SmolStr,
+    AstNode, SourceFileNode,
     SyntaxKind::*,
     SyntaxNodeRef, TextRange, TextUnit,
 };
+use ra_db::{FilesDatabase, SourceRoot, SourceRootId, WORKSPACE, SyntaxDatabase, SourceFileQuery};
 use rayon::prelude::*;
-use relative_path::RelativePath;
 use rustc_hash::FxHashSet;
 use salsa::{Database, ParallelDatabase};
+use hir::{
+    self,
+    FnSignatureInfo,
+    Problem,
+};
 
 use crate::{
     completion::{completions, CompletionItem},
-    db::{self, FileSyntaxQuery, SyntaxDatabase},
-    descriptors::{
-        function::{FnDescriptor, FnId},
-        module::{ModuleDescriptor, Problem},
-        DeclarationDescriptor, DescriptorDatabase,
-    },
-    input::{FilesDatabase, SourceRoot, SourceRootId, WORKSPACE},
-    symbol_index::SymbolIndex,
-    AnalysisChange, Cancelable, CrateGraph, CrateId, Diagnostic, FileId, FileResolver,
+    db,
+    symbol_index::{SymbolIndex, SymbolsDatabase},
+    AnalysisChange, Cancelable, CrateId, Diagnostic, FileId,
     FileSystemEdit, FilePosition, Query, SourceChange, SourceFileNodeEdit,
 };
 
-#[derive(Clone, Debug)]
-pub(crate) struct FileResolverImp {
-    inner: Arc<FileResolver>,
-}
-
-impl PartialEq for FileResolverImp {
-    fn eq(&self, other: &FileResolverImp) -> bool {
-        self.inner() == other.inner()
-    }
-}
-
-impl Eq for FileResolverImp {}
-
-impl Hash for FileResolverImp {
-    fn hash<H: Hasher>(&self, hasher: &mut H) {
-        self.inner().hash(hasher);
-    }
-}
-
-impl FileResolverImp {
-    pub(crate) fn new(inner: Arc<FileResolver>) -> FileResolverImp {
-        FileResolverImp { inner }
-    }
-    pub(crate) fn file_stem(&self, file_id: FileId) -> String {
-        self.inner.file_stem(file_id)
-    }
-    pub(crate) fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId> {
-        self.inner.resolve(file_id, path)
-    }
-    pub(crate) fn debug_path(&self, file_id: FileId) -> Option<std::path::PathBuf> {
-        self.inner.debug_path(file_id)
-    }
-    fn inner(&self) -> *const FileResolver {
-        &*self.inner
-    }
-}
-
-impl Default for FileResolverImp {
-    fn default() -> FileResolverImp {
-        #[derive(Debug)]
-        struct DummyResolver;
-        impl FileResolver for DummyResolver {
-            fn file_stem(&self, _file_: FileId) -> String {
-                panic!("file resolver not set")
-            }
-            fn resolve(
-                &self,
-                _file_id: FileId,
-                _path: &::relative_path::RelativePath,
-            ) -> Option<FileId> {
-                panic!("file resolver not set")
-            }
-        }
-        FileResolverImp {
-            inner: Arc::new(DummyResolver),
-        }
-    }
-}
-
 #[derive(Debug, Default)]
 pub(crate) struct AnalysisHostImpl {
     db: db::RootDatabase,
@@ -105,7 +44,7 @@ impl AnalysisHostImpl {
 
         for (file_id, text) in change.files_changed {
             self.db
-                .query_mut(crate::input::FileTextQuery)
+                .query_mut(ra_db::FileTextQuery)
                 .set(file_id, Arc::new(text))
         }
         if !(change.files_added.is_empty() && change.files_removed.is_empty()) {
@@ -115,22 +54,22 @@ impl AnalysisHostImpl {
             let mut source_root = SourceRoot::clone(&self.db.source_root(WORKSPACE));
             for (file_id, text) in change.files_added {
                 self.db
-                    .query_mut(crate::input::FileTextQuery)
+                    .query_mut(ra_db::FileTextQuery)
                     .set(file_id, Arc::new(text));
                 self.db
-                    .query_mut(crate::input::FileSourceRootQuery)
-                    .set(file_id, crate::input::WORKSPACE);
+                    .query_mut(ra_db::FileSourceRootQuery)
+                    .set(file_id, ra_db::WORKSPACE);
                 source_root.files.insert(file_id);
             }
             for file_id in change.files_removed {
                 self.db
-                    .query_mut(crate::input::FileTextQuery)
+                    .query_mut(ra_db::FileTextQuery)
                     .set(file_id, Arc::new(String::new()));
                 source_root.files.remove(&file_id);
             }
             source_root.file_resolver = file_resolver;
             self.db
-                .query_mut(crate::input::SourceRootQuery)
+                .query_mut(ra_db::SourceRootQuery)
                 .set(WORKSPACE, Arc::new(source_root))
         }
         if !change.libraries_added.is_empty() {
@@ -147,10 +86,10 @@ impl AnalysisHostImpl {
                         library.file_resolver.debug_path(file_id)
                     );
                     self.db
-                        .query_mut(crate::input::FileSourceRootQuery)
+                        .query_mut(ra_db::FileSourceRootQuery)
                         .set_constant(file_id, source_root_id);
                     self.db
-                        .query_mut(crate::input::FileTextQuery)
+                        .query_mut(ra_db::FileTextQuery)
                         .set_constant(file_id, Arc::new(text));
                 }
                 let source_root = SourceRoot {
@@ -158,19 +97,19 @@ impl AnalysisHostImpl {
                     file_resolver: library.file_resolver,
                 };
                 self.db
-                    .query_mut(crate::input::SourceRootQuery)
+                    .query_mut(ra_db::SourceRootQuery)
                     .set(source_root_id, Arc::new(source_root));
                 self.db
-                    .query_mut(crate::input::LibrarySymbolsQuery)
+                    .query_mut(crate::symbol_index::LibrarySymbolsQuery)
                     .set(source_root_id, Arc::new(library.symbol_index));
             }
             self.db
-                .query_mut(crate::input::LibrariesQuery)
+                .query_mut(ra_db::LibrariesQuery)
                 .set((), Arc::new(libraries));
         }
         if let Some(crate_graph) = change.crate_graph {
             self.db
-                .query_mut(crate::input::CrateGraphQuery)
+                .query_mut(ra_db::CrateGraphQuery)
                 .set((), Arc::new(crate_graph))
         }
     }
@@ -189,7 +128,7 @@ impl fmt::Debug for AnalysisImpl {
 
 impl AnalysisImpl {
     pub fn file_syntax(&self, file_id: FileId) -> SourceFileNode {
-        self.db.file_syntax(file_id)
+        self.db.source_file(file_id)
     }
     pub fn file_line_index(&self, file_id: FileId) -> Arc<LineIndex> {
         self.db.file_lines(file_id)
@@ -220,14 +159,14 @@ impl AnalysisImpl {
                 .collect()
         };
         self.db
-            .query(FileSyntaxQuery)
+            .query(SourceFileQuery)
             .sweep(salsa::SweepStrategy::default().discard_values());
         Ok(query.search(&buf))
     }
     /// This return `Vec`: a module may be included from several places. We
     /// don't handle this case yet though, so the Vec has length at most one.
     pub fn parent_module(&self, position: FilePosition) -> Cancelable<Vec<(FileId, FileSymbol)>> {
-        let descr = match ModuleDescriptor::guess_from_position(&*self.db, position)? {
+        let descr = match hir::Module::guess_from_position(&*self.db, position)? {
             None => return Ok(Vec::new()),
             Some(it) => it,
         };
@@ -246,7 +185,7 @@ impl AnalysisImpl {
     }
     /// Returns `Vec` for the same reason as `parent_module`
     pub fn crate_for(&self, file_id: FileId) -> Cancelable<Vec<CrateId>> {
-        let descr = match ModuleDescriptor::guess_from_file_id(&*self.db, file_id)? {
+        let descr = match hir::Module::guess_from_file_id(&*self.db, file_id)? {
             None => return Ok(Vec::new()),
             Some(it) => it,
         };
@@ -261,7 +200,7 @@ impl AnalysisImpl {
         Ok(crate_id.into_iter().collect())
     }
     pub fn crate_root(&self, crate_id: CrateId) -> FileId {
-        self.db.crate_graph().crate_roots[&crate_id]
+        self.db.crate_graph().crate_root(crate_id)
     }
     pub fn completions(&self, position: FilePosition) -> Cancelable<Option<Vec<CompletionItem>>> {
         completions(&self.db, position)
@@ -270,33 +209,36 @@ impl AnalysisImpl {
         &self,
         position: FilePosition,
     ) -> Cancelable<Vec<(FileId, FileSymbol)>> {
-        let file = self.db.file_syntax(position.file_id);
+        let file = self.db.source_file(position.file_id);
         let syntax = file.syntax();
         if let Some(name_ref) = find_node_at_offset::<ast::NameRef>(syntax, position.offset) {
-            // First try to resolve the symbol locally
-            return if let Some((name, range)) =
-                resolve_local_name(&self.db, position.file_id, name_ref)
+            if let Some(fn_descr) =
+                hir::Function::guess_for_name_ref(&*self.db, position.file_id, name_ref)
             {
-                let mut vec = vec![];
-                vec.push((
-                    position.file_id,
-                    FileSymbol {
-                        name,
-                        node_range: range,
-                        kind: NAME,
-                    },
-                ));
-                Ok(vec)
-            } else {
-                // If that fails try the index based approach.
-                self.index_resolve(name_ref)
-            };
+                let scope = fn_descr.scope(&*self.db);
+                // First try to resolve the symbol locally
+                return if let Some(entry) = scope.resolve_local_name(name_ref) {
+                    let mut vec = vec![];
+                    vec.push((
+                        position.file_id,
+                        FileSymbol {
+                            name: entry.name().clone(),
+                            node_range: entry.ptr().range(),
+                            kind: NAME,
+                        },
+                    ));
+                    Ok(vec)
+                } else {
+                    // If that fails try the index based approach.
+                    self.index_resolve(name_ref)
+                };
+            }
         }
         if let Some(name) = find_node_at_offset::<ast::Name>(syntax, position.offset) {
             if let Some(module) = name.syntax().parent().and_then(ast::Module::cast) {
                 if module.has_semi() {
                     let parent_module =
-                        ModuleDescriptor::guess_from_file_id(&*self.db, position.file_id)?;
+                        hir::Module::guess_from_file_id(&*self.db, position.file_id)?;
                     let child_name = module.name();
                     match (parent_module, child_name) {
                         (Some(parent_module), Some(child_name)) => {
@@ -319,32 +261,42 @@ impl AnalysisImpl {
     }
 
     pub fn find_all_refs(&self, position: FilePosition) -> Vec<(FileId, TextRange)> {
-        let file = self.db.file_syntax(position.file_id);
-        let syntax = file.syntax();
-
+        let file = self.db.source_file(position.file_id);
         // Find the binding associated with the offset
-        let maybe_binding =
-            find_node_at_offset::<ast::BindPat>(syntax, position.offset).or_else(|| {
-                let name_ref = find_node_at_offset::<ast::NameRef>(syntax, position.offset)?;
-                let resolved = resolve_local_name(&self.db, position.file_id, name_ref)?;
-                find_node_at_offset::<ast::BindPat>(syntax, resolved.1.end())
-            });
-
-        let binding = match maybe_binding {
+        let (binding, descr) = match find_binding(&self.db, &file, position) {
             None => return Vec::new(),
             Some(it) => it,
         };
 
-        let decl = DeclarationDescriptor::new(binding);
-
-        let mut ret = vec![(position.file_id, decl.range)];
+        let mut ret = vec![(position.file_id, binding.syntax().range())];
         ret.extend(
-            decl.find_all_refs()
+            descr
+                .scope(&*self.db)
+                .find_all_refs(binding)
                 .into_iter()
                 .map(|ref_desc| (position.file_id, ref_desc.range)),
         );
 
-        ret
+        return ret;
+
+        fn find_binding<'a>(
+            db: &db::RootDatabase,
+            source_file: &'a SourceFileNode,
+            position: FilePosition,
+        ) -> Option<(ast::BindPat<'a>, hir::Function)> {
+            let syntax = source_file.syntax();
+            if let Some(binding) = find_node_at_offset::<ast::BindPat>(syntax, position.offset) {
+                let descr = hir::Function::guess_for_bind_pat(db, position.file_id, binding)?;
+                return Some((binding, descr));
+            };
+            let name_ref = find_node_at_offset::<ast::NameRef>(syntax, position.offset)?;
+            let descr = hir::Function::guess_for_name_ref(db, position.file_id, name_ref)?;
+            let scope = descr.scope(db);
+            let resolved = scope.resolve_local_name(name_ref)?;
+            let resolved = resolved.ptr().resolve(source_file);
+            let binding = find_node_at_offset::<ast::BindPat>(syntax, resolved.range().end())?;
+            Some((binding, descr))
+        }
     }
 
     pub fn doc_comment_for(
@@ -352,13 +304,13 @@ impl AnalysisImpl {
         file_id: FileId,
         symbol: FileSymbol,
     ) -> Cancelable<Option<String>> {
-        let file = self.db.file_syntax(file_id);
+        let file = self.db.source_file(file_id);
 
         Ok(symbol.docs(&file))
     }
 
     pub fn diagnostics(&self, file_id: FileId) -> Cancelable<Vec<Diagnostic>> {
-        let syntax = self.db.file_syntax(file_id);
+        let syntax = self.db.source_file(file_id);
 
         let mut res = ra_editor::diagnostics(&syntax)
             .into_iter()
@@ -368,7 +320,7 @@ impl AnalysisImpl {
                 fix: None,
             })
             .collect::<Vec<_>>();
-        if let Some(m) = ModuleDescriptor::guess_from_file_id(&*self.db, file_id)? {
+        if let Some(m) = hir::Module::guess_from_file_id(&*self.db, file_id)? {
             for (name_node, problem) in m.problems(&*self.db) {
                 let diag = match problem {
                     Problem::UnresolvedModule { candidate } => {
@@ -445,8 +397,8 @@ impl AnalysisImpl {
     pub fn resolve_callable(
         &self,
         position: FilePosition,
-    ) -> Cancelable<Option<(FnDescriptor, Option<usize>)>> {
-        let file = self.db.file_syntax(position.file_id);
+    ) -> Cancelable<Option<(FnSignatureInfo, Option<usize>)>> {
+        let file = self.db.source_file(position.file_id);
         let syntax = file.syntax();
 
         // Find the calling expression and it's NameRef
@@ -455,11 +407,12 @@ impl AnalysisImpl {
 
         // Resolve the function's NameRef (NOTE: this isn't entirely accurate).
         let file_symbols = self.index_resolve(name_ref)?;
-        for (fn_fiel_id, fs) in file_symbols {
+        for (fn_file_id, fs) in file_symbols {
             if fs.kind == FN_DEF {
-                let fn_file = self.db.file_syntax(fn_fiel_id);
+                let fn_file = self.db.source_file(fn_file_id);
                 if let Some(fn_def) = find_node_at_offset(fn_file.syntax(), fs.node_range.start()) {
-                    if let Some(descriptor) = FnDescriptor::new(fn_def) {
+                    let descr = hir::Function::guess_from_source(&*self.db, fn_file_id, fn_def);
+                    if let Some(descriptor) = descr.signature_info(&*self.db) {
                         // If we have a calling expression let's find which argument we are on
                         let mut current_parameter = None;
 
@@ -532,16 +485,6 @@ impl SourceChange {
     }
 }
 
-impl CrateGraph {
-    fn crate_id_for_crate_root(&self, file_id: FileId) -> Option<CrateId> {
-        let (&crate_id, _) = self
-            .crate_roots
-            .iter()
-            .find(|(_crate_id, &root_id)| root_id == file_id)?;
-        Some(crate_id)
-    }
-}
-
 enum FnCallNode<'a> {
     CallExpr(ast::CallExpr<'a>),
     MethodCallExpr(ast::MethodCallExpr<'a>),
@@ -580,16 +523,3 @@ impl<'a> FnCallNode<'a> {
         }
     }
 }
-
-fn resolve_local_name(
-    db: &db::RootDatabase,
-    file_id: FileId,
-    name_ref: ast::NameRef,
-) -> Option<(SmolStr, TextRange)> {
-    let fn_def = name_ref.syntax().ancestors().find_map(ast::FnDef::cast)?;
-    let fn_id = FnId::get(db, file_id, fn_def);
-    let scopes = db.fn_scopes(fn_id);
-    let scope_entry = crate::descriptors::function::resolve_local_name(name_ref, &scopes)?;
-    let syntax = db.resolve_syntax_ptr(scope_entry.ptr().into_global(file_id));
-    Some((scope_entry.name().clone(), syntax.range()))
-}
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 0fbfd8a40..350a6d627 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -18,49 +18,36 @@ macro_rules! ctry {
     };
 }
 
-mod arena;
 mod db;
-mod loc2id;
-mod input;
 mod imp;
 mod completion;
-mod descriptors;
 mod symbol_index;
-mod syntax_ptr;
 pub mod mock_analysis;
 
 use std::{fmt, sync::Arc};
 
 use ra_syntax::{AtomEdit, SourceFileNode, TextRange, TextUnit};
+use ra_db::FileResolverImp;
 use rayon::prelude::*;
 use relative_path::RelativePathBuf;
 
 use crate::{
-    imp::{AnalysisHostImpl, AnalysisImpl, FileResolverImp},
+    imp::{AnalysisHostImpl, AnalysisImpl},
     symbol_index::SymbolIndex,
 };
 
 pub use crate::{
     completion::CompletionItem,
-    descriptors::function::FnDescriptor,
-    input::{CrateGraph, CrateId, FileId, FileResolver},
 };
 pub use ra_editor::{
     FileSymbol, Fold, FoldKind, HighlightedRange, LineIndex, Runnable, RunnableKind, StructureNode,
 };
+pub use hir::FnSignatureInfo;
 
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub struct Canceled;
-
-pub type Cancelable<T> = Result<T, Canceled>;
-
-impl std::fmt::Display for Canceled {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        fmt.write_str("Canceled")
-    }
-}
-
-impl std::error::Error for Canceled {}
+pub use ra_db::{
+    Canceled, Cancelable, FilePosition,
+    CrateGraph, CrateId, FileId, FileResolver
+};
 
 #[derive(Default)]
 pub struct AnalysisChange {
@@ -130,12 +117,6 @@ impl AnalysisHost {
     }
 }
 
-#[derive(Clone, Copy, Debug)]
-pub struct FilePosition {
-    pub file_id: FileId,
-    pub offset: TextUnit,
-}
-
 #[derive(Debug)]
 pub struct SourceChange {
     pub label: String,
@@ -305,7 +286,7 @@ impl Analysis {
     pub fn resolve_callable(
         &self,
         position: FilePosition,
-    ) -> Cancelable<Option<(FnDescriptor, Option<usize>)>> {
+    ) -> Cancelable<Option<(FnSignatureInfo, Option<usize>)>> {
         self.imp.resolve_callable(position)
     }
 }
@@ -336,3 +317,112 @@ fn analysis_is_send() {
     fn is_send<T: Send>() {}
     is_send::<Analysis>();
 }
+
+//TODO: move to hir
+#[cfg(test)]
+mod hir_namres_tests {
+    use std::sync::Arc;
+    use ra_db::FilesDatabase;
+    use ra_syntax::SmolStr;
+    use hir::{self, db::HirDatabase};
+
+    use crate::{
+        AnalysisChange,
+        mock_analysis::{MockAnalysis, analysis_and_position},
+};
+
+    fn item_map(fixture: &str) -> (Arc<hir::ItemMap>, hir::ModuleId) {
+        let (analysis, pos) = analysis_and_position(fixture);
+        let db = analysis.imp.db;
+        let source_root = db.file_source_root(pos.file_id);
+        let descr = hir::Module::guess_from_position(&*db, pos)
+            .unwrap()
+            .unwrap();
+        let module_id = descr.module_id;
+        (db.item_map(source_root).unwrap(), module_id)
+    }
+
+    #[test]
+    fn test_item_map() {
+        let (item_map, module_id) = item_map(
+            "
+            //- /lib.rs
+            mod foo;
+
+            use crate::foo::bar::Baz;
+            <|>
+
+            //- /foo/mod.rs
+            pub mod bar;
+
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+        );
+        let name = SmolStr::from("Baz");
+        let resolution = &item_map.per_module[&module_id].items[&name];
+        assert!(resolution.def_id.is_some());
+    }
+
+    #[test]
+    fn typing_inside_a_function_should_not_invalidate_item_map() {
+        let mock_analysis = MockAnalysis::with_files(
+            "
+            //- /lib.rs
+            mod foo;
+
+            use crate::foo::bar::Baz;
+
+            fn foo() -> i32 {
+                1 + 1
+            }
+            //- /foo/mod.rs
+            pub mod bar;
+
+            //- /foo/bar.rs
+            pub struct Baz;
+        ",
+        );
+
+        let file_id = mock_analysis.id_of("/lib.rs");
+        let mut host = mock_analysis.analysis_host();
+
+        let source_root = host.analysis().imp.db.file_source_root(file_id);
+
+        {
+            let db = host.analysis().imp.db;
+            let events = db.log_executed(|| {
+                db.item_map(source_root).unwrap();
+            });
+            assert!(format!("{:?}", events).contains("item_map"))
+        }
+
+        let mut change = AnalysisChange::new();
+
+        change.change_file(
+            file_id,
+            "
+            mod foo;
+
+            use crate::foo::bar::Baz;
+
+            fn foo() -> i32 { 92 }
+        "
+            .to_string(),
+        );
+
+        host.apply_change(change);
+
+        {
+            let db = host.analysis().imp.db;
+            let events = db.log_executed(|| {
+                db.item_map(source_root).unwrap();
+            });
+            assert!(
+                !format!("{:?}", events).contains("_item_map"),
+                "{:#?}",
+                events
+            )
+        }
+    }
+}
diff --git a/crates/ra_analysis/src/loc2id.rs b/crates/ra_analysis/src/loc2id.rs
deleted file mode 100644
index c7c799a91..000000000
--- a/crates/ra_analysis/src/loc2id.rs
+++ /dev/null
@@ -1,141 +0,0 @@
-use parking_lot::Mutex;
-
-use std::{
-    hash::Hash,
-    sync::Arc,
-};
-
-use rustc_hash::FxHashMap;
-
-use crate::{
-    FileId,
-    descriptors::FileItemId,
-    descriptors::module::ModuleId,
-    syntax_ptr::SyntaxPtr,
-    input::SourceRootId,
-};
-
-/// There are two principle ways to refer to things:
-///   - by their locatinon (module in foo/bar/baz.rs at line 42)
-///   - by their numeric id (module `ModuleId(42)`)
-///
-/// The first one is more powerful (you can actually find the thing in question
-/// by id), but the second one is so much more compact.
-///
-/// `Loc2IdMap` allows us to have a cake an eat it as well: by maintaining a
-/// bidirectional mapping between positional and numeric ids, we can use compact
-/// representation wich still allows us to get the actual item
-#[derive(Debug)]
-pub(crate) struct Loc2IdMap<L, ID>
-where
-    ID: NumericId,
-    L: Clone + Eq + Hash,
-{
-    loc2id: FxHashMap<L, ID>,
-    id2loc: FxHashMap<ID, L>,
-}
-
-impl<L, ID> Default for Loc2IdMap<L, ID>
-where
-    ID: NumericId,
-    L: Clone + Eq + Hash,
-{
-    fn default() -> Self {
-        Loc2IdMap {
-            loc2id: FxHashMap::default(),
-            id2loc: FxHashMap::default(),
-        }
-    }
-}
-
-impl<L, ID> Loc2IdMap<L, ID>
-where
-    ID: NumericId,
-    L: Clone + Eq + Hash,
-{
-    pub fn loc2id(&mut self, loc: &L) -> ID {
-        match self.loc2id.get(loc) {
-            Some(id) => return id.clone(),
-            None => (),
-        }
-        let id = self.loc2id.len();
-        assert!(id < u32::max_value() as usize);
-        let id = ID::from_u32(id as u32);
-        self.loc2id.insert(loc.clone(), id.clone());
-        self.id2loc.insert(id.clone(), loc.clone());
-        id
-    }
-
-    pub fn id2loc(&self, id: ID) -> L {
-        self.id2loc[&id].clone()
-    }
-}
-
-pub(crate) trait NumericId: Clone + Eq + Hash {
-    fn from_u32(id: u32) -> Self;
-    fn to_u32(self) -> u32;
-}
-
-macro_rules! impl_numeric_id {
-    ($id:ident) => {
-        impl NumericId for $id {
-            fn from_u32(id: u32) -> Self {
-                $id(id)
-            }
-            fn to_u32(self) -> u32 {
-                self.0
-            }
-        }
-    };
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct FnId(u32);
-impl_numeric_id!(FnId);
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct DefId(u32);
-impl_numeric_id!(DefId);
-
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub(crate) enum DefLoc {
-    Module {
-        id: ModuleId,
-        source_root: SourceRootId,
-    },
-    Item {
-        file_id: FileId,
-        id: FileItemId,
-    },
-}
-
-pub(crate) trait IdDatabase: salsa::Database {
-    fn id_maps(&self) -> &IdMaps;
-}
-
-#[derive(Debug, Default, Clone)]
-pub(crate) struct IdMaps {
-    inner: Arc<IdMapsInner>,
-}
-
-impl IdMaps {
-    pub(crate) fn fn_id(&self, ptr: SyntaxPtr) -> FnId {
-        self.inner.fns.lock().loc2id(&ptr)
-    }
-    pub(crate) fn fn_ptr(&self, fn_id: FnId) -> SyntaxPtr {
-        self.inner.fns.lock().id2loc(fn_id)
-    }
-
-    pub(crate) fn def_id(&self, loc: DefLoc) -> DefId {
-        self.inner.defs.lock().loc2id(&loc)
-    }
-    pub(crate) fn def_loc(&self, def_id: DefId) -> DefLoc {
-        self.inner.defs.lock().id2loc(def_id)
-    }
-}
-
-#[derive(Debug, Default)]
-struct IdMapsInner {
-    fns: Mutex<Loc2IdMap<SyntaxPtr, FnId>>,
-    defs: Mutex<Loc2IdMap<DefLoc, DefId>>,
-}
diff --git a/crates/ra_analysis/src/symbol_index.rs b/crates/ra_analysis/src/symbol_index.rs
index 3a0667ecd..b48a37229 100644
--- a/crates/ra_analysis/src/symbol_index.rs
+++ b/crates/ra_analysis/src/symbol_index.rs
@@ -4,14 +4,36 @@ use std::{
 };
 
 use fst::{self, Streamer};
-use ra_editor::{file_symbols, FileSymbol};
+use ra_editor::{self, FileSymbol};
 use ra_syntax::{
     SourceFileNode,
     SyntaxKind::{self, *},
 };
+use ra_db::{SyntaxDatabase, SourceRootId};
 use rayon::prelude::*;
 
-use crate::{FileId, Query};
+use crate::{
+    Cancelable,
+    FileId, Query,
+};
+
+salsa::query_group! {
+    pub(crate) trait SymbolsDatabase: SyntaxDatabase {
+        fn file_symbols(file_id: FileId) -> Cancelable<Arc<SymbolIndex>> {
+            type FileSymbolsQuery;
+        }
+        fn library_symbols(id: SourceRootId) -> Arc<SymbolIndex> {
+            type LibrarySymbolsQuery;
+            storage input;
+        }
+    }
+}
+
+fn file_symbols(db: &impl SyntaxDatabase, file_id: FileId) -> Cancelable<Arc<SymbolIndex>> {
+    db.check_canceled()?;
+    let syntax = db.source_file(file_id);
+    Ok(Arc::new(SymbolIndex::for_file(file_id, syntax)))
+}
 
 #[derive(Default, Debug)]
 pub(crate) struct SymbolIndex {
@@ -39,7 +61,7 @@ impl SymbolIndex {
     ) -> SymbolIndex {
         let mut symbols = files
             .flat_map(|(file_id, file)| {
-                file_symbols(&file)
+                ra_editor::file_symbols(&file)
                     .into_iter()
                     .map(move |symbol| (symbol.name.as_str().to_lowercase(), (file_id, symbol)))
                     .collect::<Vec<_>>()
diff --git a/crates/ra_analysis/tests/tests.rs b/crates/ra_analysis/tests/tests.rs
index 72b2ebf97..fbe89f444 100644
--- a/crates/ra_analysis/tests/tests.rs
+++ b/crates/ra_analysis/tests/tests.rs
@@ -10,10 +10,10 @@ use test_utils::assert_eq_dbg;
 
 use ra_analysis::{
     mock_analysis::{analysis_and_position, single_file, single_file_with_position, MockAnalysis},
-    AnalysisChange, CrateGraph, FileId, FnDescriptor,
+    AnalysisChange, CrateGraph, FileId, FnSignatureInfo,
 };
 
-fn get_signature(text: &str) -> (FnDescriptor, Option<usize>) {
+fn get_signature(text: &str) -> (FnSignatureInfo, Option<usize>) {
     let (analysis, position) = single_file_with_position(text);
     analysis.resolve_callable(position).unwrap().unwrap()
 }
@@ -126,7 +126,7 @@ fn test_resolve_crate_root() {
     let mut host = mock.analysis_host();
     assert!(host.analysis().crate_for(mod_file).unwrap().is_empty());
 
-    let mut crate_graph = CrateGraph::new();
+    let mut crate_graph = CrateGraph::default();
     let crate_id = crate_graph.add_crate_root(root_file);
     let mut change = AnalysisChange::new();
     change.set_crate_graph(crate_graph);
diff --git a/crates/ra_db/Cargo.toml b/crates/ra_db/Cargo.toml
new file mode 100644
index 000000000..3bf2f635e
--- /dev/null
+++ b/crates/ra_db/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+edition = "2018"
+name = "ra_db"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+log = "0.4.5"
+relative-path = "0.4.0"
+salsa = "0.8.0"
+rustc-hash = "1.0"
+parking_lot = "0.6.4"
+id-arena = { git = "https://github.com/fitzgen/id-arena/", rev = "43ecd67" }
+ra_syntax = { path = "../ra_syntax" }
+ra_editor = { path = "../ra_editor" }
+test_utils = { path = "../test_utils" }
diff --git a/crates/ra_db/src/file_resolver.rs b/crates/ra_db/src/file_resolver.rs
new file mode 100644
index 000000000..f849ac752
--- /dev/null
+++ b/crates/ra_db/src/file_resolver.rs
@@ -0,0 +1,76 @@
+use std::{
+    sync::Arc,
+    hash::{Hash, Hasher},
+    fmt,
+};
+
+use relative_path::RelativePath;
+
+use crate::input::FileId;
+
+pub trait FileResolver: fmt::Debug + Send + Sync + 'static {
+    fn file_stem(&self, file_id: FileId) -> String;
+    fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId>;
+    fn debug_path(&self, _1file_id: FileId) -> Option<std::path::PathBuf> {
+        None
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct FileResolverImp {
+    inner: Arc<FileResolver>,
+}
+
+impl PartialEq for FileResolverImp {
+    fn eq(&self, other: &FileResolverImp) -> bool {
+        self.inner() == other.inner()
+    }
+}
+
+impl Eq for FileResolverImp {}
+
+impl Hash for FileResolverImp {
+    fn hash<H: Hasher>(&self, hasher: &mut H) {
+        self.inner().hash(hasher);
+    }
+}
+
+impl FileResolverImp {
+    pub fn new(inner: Arc<FileResolver>) -> FileResolverImp {
+        FileResolverImp { inner }
+    }
+    pub fn file_stem(&self, file_id: FileId) -> String {
+        self.inner.file_stem(file_id)
+    }
+    pub fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId> {
+        self.inner.resolve(file_id, path)
+    }
+    pub fn debug_path(&self, file_id: FileId) -> Option<std::path::PathBuf> {
+        self.inner.debug_path(file_id)
+    }
+    fn inner(&self) -> *const FileResolver {
+        &*self.inner
+    }
+}
+
+impl Default for FileResolverImp {
+    fn default() -> FileResolverImp {
+        #[derive(Debug)]
+        struct DummyResolver;
+        impl FileResolver for DummyResolver {
+            fn file_stem(&self, _file_: FileId) -> String {
+                panic!("file resolver not set")
+            }
+            fn resolve(
+                &self,
+                _file_id: FileId,
+                _path: &::relative_path::RelativePath,
+            ) -> Option<FileId> {
+                panic!("file resolver not set")
+            }
+        }
+        FileResolverImp {
+            inner: Arc::new(DummyResolver),
+        }
+    }
+}
diff --git a/crates/ra_analysis/src/input.rs b/crates/ra_db/src/input.rs
index a78b6e397..9101ac7a8 100644
--- a/crates/ra_analysis/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -1,11 +1,10 @@
-use std::{fmt, sync::Arc};
+use std::sync::Arc;
 
-use relative_path::RelativePath;
 use rustc_hash::FxHashMap;
 use rustc_hash::FxHashSet;
 use salsa;
 
-use crate::{symbol_index::SymbolIndex, FileResolverImp};
+use crate::file_resolver::FileResolverImp;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct FileId(pub u32);
@@ -19,8 +18,8 @@ pub struct CrateGraph {
 }
 
 impl CrateGraph {
-    pub fn new() -> CrateGraph {
-        CrateGraph::default()
+    pub fn crate_root(&self, crate_id: CrateId) -> FileId {
+        self.crate_roots[&crate_id]
     }
     pub fn add_crate_root(&mut self, file_id: FileId) -> CrateId {
         let crate_id = CrateId(self.crate_roots.len() as u32);
@@ -28,18 +27,17 @@ impl CrateGraph {
         assert!(prev.is_none());
         crate_id
     }
-}
-
-pub trait FileResolver: fmt::Debug + Send + Sync + 'static {
-    fn file_stem(&self, file_id: FileId) -> String;
-    fn resolve(&self, file_id: FileId, path: &RelativePath) -> Option<FileId>;
-    fn debug_path(&self, _file_id: FileId) -> Option<std::path::PathBuf> {
-        None
+    pub fn crate_id_for_crate_root(&self, file_id: FileId) -> Option<CrateId> {
+        let (&crate_id, _) = self
+            .crate_roots
+            .iter()
+            .find(|(_crate_id, &root_id)| root_id == file_id)?;
+        Some(crate_id)
     }
 }
 
 salsa::query_group! {
-    pub(crate) trait FilesDatabase: salsa::Database {
+    pub trait FilesDatabase: salsa::Database {
         fn file_text(file_id: FileId) -> Arc<String> {
             type FileTextQuery;
             storage input;
@@ -56,10 +54,6 @@ salsa::query_group! {
             type LibrariesQuery;
             storage input;
         }
-        fn library_symbols(id: SourceRootId) -> Arc<SymbolIndex> {
-            type LibrarySymbolsQuery;
-            storage input;
-        }
         fn crate_graph() -> Arc<CrateGraph> {
             type CrateGraphQuery;
             storage input;
@@ -68,12 +62,12 @@ salsa::query_group! {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
-pub(crate) struct SourceRootId(pub(crate) u32);
+pub struct SourceRootId(pub u32);
 
 #[derive(Default, Clone, Debug, PartialEq, Eq)]
-pub(crate) struct SourceRoot {
-    pub(crate) file_resolver: FileResolverImp,
-    pub(crate) files: FxHashSet<FileId>,
+pub struct SourceRoot {
+    pub file_resolver: FileResolverImp,
+    pub files: FxHashSet<FileId>,
 }
 
-pub(crate) const WORKSPACE: SourceRootId = SourceRootId(0);
+pub const WORKSPACE: SourceRootId = SourceRootId(0);
diff --git a/crates/ra_db/src/lib.rs b/crates/ra_db/src/lib.rs
new file mode 100644
index 000000000..33cb0e2ec
--- /dev/null
+++ b/crates/ra_db/src/lib.rs
@@ -0,0 +1,89 @@
+//! ra_db defines basic database traits. Concrete DB is defined by ra_analysis.
+
+extern crate ra_editor;
+extern crate ra_syntax;
+extern crate relative_path;
+extern crate rustc_hash;
+extern crate salsa;
+
+mod syntax_ptr;
+mod file_resolver;
+mod input;
+mod loc2id;
+
+use std::sync::Arc;
+use ra_editor::LineIndex;
+use ra_syntax::{TextUnit, SourceFileNode};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Canceled;
+
+pub type Cancelable<T> = Result<T, Canceled>;
+
+impl std::fmt::Display for Canceled {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        fmt.write_str("Canceled")
+    }
+}
+
+impl std::error::Error for Canceled {}
+
+pub use crate::{
+    syntax_ptr::LocalSyntaxPtr,
+    file_resolver::{FileResolver, FileResolverImp},
+    input::{
+        FilesDatabase, FileId, CrateId, SourceRoot, SourceRootId, CrateGraph, WORKSPACE,
+        FileTextQuery, FileSourceRootQuery, SourceRootQuery, LibrariesQuery, CrateGraphQuery,
+    },
+    loc2id::{LocationIntener, NumericId},
+};
+
+#[macro_export]
+macro_rules! impl_numeric_id {
+    ($id:ident) => {
+        impl $crate::NumericId for $id {
+            fn from_u32(id: u32) -> Self {
+                $id(id)
+            }
+            fn to_u32(self) -> u32 {
+                self.0
+            }
+        }
+    };
+}
+
+pub trait BaseDatabase: salsa::Database {
+    fn check_canceled(&self) -> Cancelable<()> {
+        if self.salsa_runtime().is_current_revision_canceled() {
+            Err(Canceled)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+salsa::query_group! {
+    pub trait SyntaxDatabase: crate::input::FilesDatabase + BaseDatabase {
+        fn source_file(file_id: FileId) -> SourceFileNode {
+            type SourceFileQuery;
+        }
+        fn file_lines(file_id: FileId) -> Arc<LineIndex> {
+            type FileLinesQuery;
+        }
+    }
+}
+
+fn source_file(db: &impl SyntaxDatabase, file_id: FileId) -> SourceFileNode {
+    let text = db.file_text(file_id);
+    SourceFileNode::parse(&*text)
+}
+fn file_lines(db: &impl SyntaxDatabase, file_id: FileId) -> Arc<LineIndex> {
+    let text = db.file_text(file_id);
+    Arc::new(LineIndex::new(&*text))
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct FilePosition {
+    pub file_id: FileId,
+    pub offset: TextUnit,
+}
diff --git a/crates/ra_db/src/loc2id.rs b/crates/ra_db/src/loc2id.rs
new file mode 100644
index 000000000..69ba43d0f
--- /dev/null
+++ b/crates/ra_db/src/loc2id.rs
@@ -0,0 +1,100 @@
+use parking_lot::Mutex;
+
+use std::hash::Hash;
+
+use rustc_hash::FxHashMap;
+
+/// There are two principle ways to refer to things:
+///   - by their locatinon (module in foo/bar/baz.rs at line 42)
+///   - by their numeric id (module `ModuleId(42)`)
+///
+/// The first one is more powerful (you can actually find the thing in question
+/// by id), but the second one is so much more compact.
+///
+/// `Loc2IdMap` allows us to have a cake an eat it as well: by maintaining a
+/// bidirectional mapping between positional and numeric ids, we can use compact
+/// representation wich still allows us to get the actual item
+#[derive(Debug)]
+struct Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    loc2id: FxHashMap<LOC, ID>,
+    id2loc: FxHashMap<ID, LOC>,
+}
+
+impl<LOC, ID> Default for Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    fn default() -> Self {
+        Loc2IdMap {
+            loc2id: FxHashMap::default(),
+            id2loc: FxHashMap::default(),
+        }
+    }
+}
+
+impl<LOC, ID> Loc2IdMap<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    pub fn loc2id(&mut self, loc: &LOC) -> ID {
+        match self.loc2id.get(loc) {
+            Some(id) => return id.clone(),
+            None => (),
+        }
+        let id = self.loc2id.len();
+        assert!(id < u32::max_value() as usize);
+        let id = ID::from_u32(id as u32);
+        self.loc2id.insert(loc.clone(), id.clone());
+        self.id2loc.insert(id.clone(), loc.clone());
+        id
+    }
+
+    pub fn id2loc(&self, id: ID) -> LOC {
+        self.id2loc[&id].clone()
+    }
+}
+
+pub trait NumericId: Clone + Eq + Hash {
+    fn from_u32(id: u32) -> Self;
+    fn to_u32(self) -> u32;
+}
+
+#[derive(Debug)]
+pub struct LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    map: Mutex<Loc2IdMap<LOC, ID>>,
+}
+
+impl<LOC, ID> Default for LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    fn default() -> Self {
+        LocationIntener {
+            map: Default::default(),
+        }
+    }
+}
+
+impl<LOC, ID> LocationIntener<LOC, ID>
+where
+    ID: NumericId,
+    LOC: Clone + Eq + Hash,
+{
+    pub fn loc2id(&self, loc: &LOC) -> ID {
+        self.map.lock().loc2id(loc)
+    }
+    pub fn id2loc(&self, id: ID) -> LOC {
+        self.map.lock().id2loc(id)
+    }
+}
diff --git a/crates/ra_analysis/src/syntax_ptr.rs b/crates/ra_db/src/syntax_ptr.rs
index e45934ce0..dac94dd36 100644
--- a/crates/ra_analysis/src/syntax_ptr.rs
+++ b/crates/ra_db/src/syntax_ptr.rs
@@ -1,49 +1,21 @@
 use ra_syntax::{SourceFileNode, SyntaxKind, SyntaxNode, SyntaxNodeRef, TextRange};
 
-use crate::db::SyntaxDatabase;
-use crate::FileId;
-
-pub(crate) fn resolve_syntax_ptr(db: &impl SyntaxDatabase, ptr: SyntaxPtr) -> SyntaxNode {
-    let syntax = db.file_syntax(ptr.file_id);
-    ptr.local.resolve(&syntax)
-}
-
-/// SyntaxPtr is a cheap `Copy` id which identifies a particular syntax node,
-/// without retaining syntax tree in memory. You need to explicitly `resolve`
-/// `SyntaxPtr` to get a `SyntaxNode`
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct SyntaxPtr {
-    file_id: FileId,
-    local: LocalSyntaxPtr,
-}
-
-impl SyntaxPtr {
-    pub(crate) fn new(file_id: FileId, node: SyntaxNodeRef) -> SyntaxPtr {
-        let local = LocalSyntaxPtr::new(node);
-        SyntaxPtr { file_id, local }
-    }
-
-    pub(crate) fn file_id(self) -> FileId {
-        self.file_id
-    }
-}
-
 /// A pionter to a syntax node inside a file.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) struct LocalSyntaxPtr {
+pub struct LocalSyntaxPtr {
     range: TextRange,
     kind: SyntaxKind,
 }
 
 impl LocalSyntaxPtr {
-    pub(crate) fn new(node: SyntaxNodeRef) -> LocalSyntaxPtr {
+    pub fn new(node: SyntaxNodeRef) -> LocalSyntaxPtr {
         LocalSyntaxPtr {
             range: node.range(),
             kind: node.kind(),
         }
     }
 
-    pub(crate) fn resolve(self, file: &SourceFileNode) -> SyntaxNode {
+    pub fn resolve(self, file: &SourceFileNode) -> SyntaxNode {
         let mut curr = file.syntax();
         loop {
             if curr.range() == self.range && curr.kind() == self.kind {
@@ -56,11 +28,8 @@ impl LocalSyntaxPtr {
         }
     }
 
-    pub(crate) fn into_global(self, file_id: FileId) -> SyntaxPtr {
-        SyntaxPtr {
-            file_id,
-            local: self,
-        }
+    pub fn range(self) -> TextRange {
+        self.range
     }
 }
 
diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
new file mode 100644
index 000000000..9bde289e7
--- /dev/null
+++ b/crates/ra_hir/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+edition = "2018"
+name = "ra_hir"
+version = "0.1.0"
+authors = ["Aleksey Kladov <[email protected]>"]
+
+[dependencies]
+log = "0.4.5"
+relative-path = "0.4.0"
+salsa = "0.8.0"
+rustc-hash = "1.0"
+parking_lot = "0.6.4"
+id-arena = { git = "https://github.com/fitzgen/id-arena/", rev = "43ecd67" }
+ra_syntax = { path = "../ra_syntax" }
+ra_editor = { path = "../ra_editor" }
+ra_db = { path = "../ra_db" }
+test_utils = { path = "../test_utils" }
diff --git a/crates/ra_analysis/src/arena.rs b/crates/ra_hir/src/arena.rs
index a752ec0c1..8d67ab1c9 100644
--- a/crates/ra_analysis/src/arena.rs
+++ b/crates/ra_hir/src/arena.rs
@@ -8,7 +8,7 @@ use std::{
     marker::PhantomData,
 };
 
-pub(crate) struct Id<T> {
+pub struct Id<T> {
     idx: u32,
     _ty: PhantomData<fn() -> T>,
 }
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
new file mode 100644
index 000000000..2f01bae6d
--- /dev/null
+++ b/crates/ra_hir/src/db.rs
@@ -0,0 +1,66 @@
+use std::sync::Arc;
+
+use ra_syntax::{
+    SyntaxNode,
+    ast::FnDefNode,
+};
+use ra_db::{SourceRootId, LocationIntener, SyntaxDatabase, FileId, Cancelable};
+
+use crate::{
+    DefLoc, DefId, FnId,
+    SourceFileItems, SourceItemId,
+    query_definitions,
+    FnScopes,
+    module::{ModuleId, ModuleTree, ModuleSource,
+    nameres::{ItemMap, InputModuleItems}},
+};
+
+salsa::query_group! {
+
+pub trait HirDatabase: SyntaxDatabase
+    + AsRef<LocationIntener<DefLoc, DefId>>
+    + AsRef<LocationIntener<SourceItemId, FnId>>
+{
+    fn fn_scopes(fn_id: FnId) -> Arc<FnScopes> {
+        type FnScopesQuery;
+        use fn query_definitions::fn_scopes;
+    }
+    fn fn_syntax(fn_id: FnId) -> FnDefNode {
+        type FnSyntaxQuery;
+        // Don't retain syntax trees in memory
+        storage dependencies;
+        use fn query_definitions::fn_syntax;
+    }
+
+    fn file_items(file_id: FileId) -> Arc<SourceFileItems> {
+        type SourceFileItemsQuery;
+        storage dependencies;
+        use fn query_definitions::file_items;
+    }
+
+    fn file_item(source_item_id: SourceItemId) -> SyntaxNode {
+        type FileItemQuery;
+        storage dependencies;
+        use fn query_definitions::file_item;
+    }
+
+    fn submodules(source: ModuleSource) -> Cancelable<Arc<Vec<crate::module::imp::Submodule>>> {
+        type SubmodulesQuery;
+        use fn query_definitions::submodules;
+    }
+
+    fn input_module_items(source_root_id: SourceRootId, module_id: ModuleId) -> Cancelable<Arc<InputModuleItems>> {
+        type InputModuleItemsQuery;
+        use fn query_definitions::input_module_items;
+    }
+    fn item_map(source_root_id: SourceRootId) -> Cancelable<Arc<ItemMap>> {
+        type ItemMapQuery;
+        use fn query_definitions::item_map;
+    }
+    fn module_tree(source_root_id: SourceRootId) -> Cancelable<Arc<ModuleTree>> {
+        type ModuleTreeQuery;
+        use fn crate::module::imp::module_tree;
+    }
+}
+
+}
diff --git a/crates/ra_analysis/src/descriptors/function/mod.rs b/crates/ra_hir/src/function/mod.rs
index 86eee5e93..c8af2e54f 100644
--- a/crates/ra_analysis/src/descriptors/function/mod.rs
+++ b/crates/ra_hir/src/function/mod.rs
@@ -1,30 +1,83 @@
-pub(super) mod imp;
 mod scope;
 
-use std::cmp::{max, min};
+use std::{
+    cmp::{max, min},
+    sync::Arc,
+};
 
 use ra_syntax::{
+    TextRange, TextUnit, SyntaxNodeRef,
     ast::{self, AstNode, DocCommentsOwner, NameOwner},
-    TextRange, TextUnit,
 };
+use ra_db::FileId;
 
 use crate::{
-    syntax_ptr::SyntaxPtr, FileId,
-    loc2id::IdDatabase,
+    FnId, HirDatabase, SourceItemId,
 };
 
-pub(crate) use self::scope::{resolve_local_name, FnScopes};
-pub(crate) use crate::loc2id::FnId;
+pub use self::scope::FnScopes;
 
 impl FnId {
-    pub(crate) fn get(db: &impl IdDatabase, file_id: FileId, fn_def: ast::FnDef) -> FnId {
-        let ptr = SyntaxPtr::new(file_id, fn_def.syntax());
-        db.id_maps().fn_id(ptr)
+    pub fn get(db: &impl HirDatabase, file_id: FileId, fn_def: ast::FnDef) -> FnId {
+        let file_items = db.file_items(file_id);
+        let item_id = file_items.id_of(fn_def.syntax());
+        let item_id = SourceItemId { file_id, item_id };
+        FnId::from_loc(db, &item_id)
+    }
+}
+
+pub struct Function {
+    fn_id: FnId,
+}
+
+impl Function {
+    pub fn guess_from_source(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        fn_def: ast::FnDef,
+    ) -> Function {
+        let fn_id = FnId::get(db, file_id, fn_def);
+        Function { fn_id }
+    }
+
+    pub fn guess_for_name_ref(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        name_ref: ast::NameRef,
+    ) -> Option<Function> {
+        Function::guess_for_node(db, file_id, name_ref.syntax())
+    }
+
+    pub fn guess_for_bind_pat(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        bind_pat: ast::BindPat,
+    ) -> Option<Function> {
+        Function::guess_for_node(db, file_id, bind_pat.syntax())
+    }
+
+    fn guess_for_node(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        node: SyntaxNodeRef,
+    ) -> Option<Function> {
+        let fn_def = node.ancestors().find_map(ast::FnDef::cast)?;
+        let res = Function::guess_from_source(db, file_id, fn_def);
+        Some(res)
+    }
+
+    pub fn scope(&self, db: &impl HirDatabase) -> Arc<FnScopes> {
+        db.fn_scopes(self.fn_id)
+    }
+
+    pub fn signature_info(&self, db: &impl HirDatabase) -> Option<FnSignatureInfo> {
+        let syntax = db.fn_syntax(self.fn_id);
+        FnSignatureInfo::new(syntax.borrowed())
     }
 }
 
 #[derive(Debug, Clone)]
-pub struct FnDescriptor {
+pub struct FnSignatureInfo {
     pub name: String,
     pub label: String,
     pub ret_type: Option<String>,
@@ -32,8 +85,8 @@ pub struct FnDescriptor {
     pub doc: Option<String>,
 }
 
-impl FnDescriptor {
-    pub fn new(node: ast::FnDef) -> Option<Self> {
+impl FnSignatureInfo {
+    fn new(node: ast::FnDef) -> Option<Self> {
         let name = node.name()?.text().to_string();
 
         let mut doc = None;
@@ -52,7 +105,7 @@ impl FnDescriptor {
             node.syntax().text().to_string()
         };
 
-        if let Some((comment_range, docs)) = FnDescriptor::extract_doc_comments(node) {
+        if let Some((comment_range, docs)) = FnSignatureInfo::extract_doc_comments(node) {
             let comment_range = comment_range
                 .checked_sub(node.syntax().range().start())
                 .unwrap();
@@ -84,10 +137,10 @@ impl FnDescriptor {
             }
         }
 
-        let params = FnDescriptor::param_list(node);
+        let params = FnSignatureInfo::param_list(node);
         let ret_type = node.ret_type().map(|r| r.syntax().text().to_string());
 
-        Some(FnDescriptor {
+        Some(FnSignatureInfo {
             name,
             ret_type,
             params,
diff --git a/crates/ra_analysis/src/descriptors/function/scope.rs b/crates/ra_hir/src/function/scope.rs
index 5307a0a8e..863453291 100644
--- a/crates/ra_analysis/src/descriptors/function/scope.rs
+++ b/crates/ra_hir/src/function/scope.rs
@@ -1,13 +1,13 @@
 use rustc_hash::{FxHashMap, FxHashSet};
 
 use ra_syntax::{
+    AstNode, SmolStr, SyntaxNodeRef, TextRange,
     algo::generate,
     ast::{self, ArgListOwner, LoopBodyOwner, NameOwner},
-    AstNode, SmolStr, SyntaxNodeRef,
 };
+use ra_db::LocalSyntaxPtr;
 
 use crate::{
-    syntax_ptr::LocalSyntaxPtr,
     arena::{Arena, Id},
 };
 
@@ -15,7 +15,7 @@ pub(crate) type ScopeId = Id<ScopeData>;
 
 #[derive(Debug, PartialEq, Eq)]
 pub struct FnScopes {
-    pub(crate) self_param: Option<LocalSyntaxPtr>,
+    pub self_param: Option<LocalSyntaxPtr>,
     scopes: Arena<ScopeData>,
     scope_for: FxHashMap<LocalSyntaxPtr, ScopeId>,
 }
@@ -27,13 +27,13 @@ pub struct ScopeEntry {
 }
 
 #[derive(Debug, PartialEq, Eq)]
-pub(crate) struct ScopeData {
+pub struct ScopeData {
     parent: Option<ScopeId>,
     entries: Vec<ScopeEntry>,
 }
 
 impl FnScopes {
-    pub(crate) fn new(fn_def: ast::FnDef) -> FnScopes {
+    pub fn new(fn_def: ast::FnDef) -> FnScopes {
         let mut scopes = FnScopes {
             self_param: fn_def
                 .param_list()
@@ -49,7 +49,7 @@ impl FnScopes {
         }
         scopes
     }
-    pub(crate) fn entries(&self, scope: ScopeId) -> &[ScopeEntry] {
+    pub fn entries(&self, scope: ScopeId) -> &[ScopeEntry] {
         &self.scopes[scope].entries
     }
     pub fn scope_chain<'a>(&'a self, node: SyntaxNodeRef) -> impl Iterator<Item = ScopeId> + 'a {
@@ -57,6 +57,37 @@ impl FnScopes {
             self.scopes[scope].parent
         })
     }
+    pub fn resolve_local_name<'a>(&'a self, name_ref: ast::NameRef) -> Option<&'a ScopeEntry> {
+        let mut shadowed = FxHashSet::default();
+        let ret = self
+            .scope_chain(name_ref.syntax())
+            .flat_map(|scope| self.entries(scope).iter())
+            .filter(|entry| shadowed.insert(entry.name()))
+            .filter(|entry| entry.name() == &name_ref.text())
+            .nth(0);
+        ret
+    }
+
+    pub fn find_all_refs(&self, pat: ast::BindPat) -> Vec<ReferenceDescriptor> {
+        let fn_def = pat.syntax().ancestors().find_map(ast::FnDef::cast).unwrap();
+        let name_ptr = LocalSyntaxPtr::new(pat.syntax());
+        let refs: Vec<_> = fn_def
+            .syntax()
+            .descendants()
+            .filter_map(ast::NameRef::cast)
+            .filter(|name_ref| match self.resolve_local_name(*name_ref) {
+                None => false,
+                Some(entry) => entry.ptr() == name_ptr,
+            })
+            .map(|name_ref| ReferenceDescriptor {
+                name: name_ref.syntax().text().to_string(),
+                range: name_ref.syntax().range(),
+            })
+            .collect();
+
+        refs
+    }
+
     fn root_scope(&mut self) -> ScopeId {
         self.scopes.alloc(ScopeData {
             parent: None,
@@ -104,10 +135,10 @@ impl ScopeEntry {
         };
         Some(res)
     }
-    pub(crate) fn name(&self) -> &SmolStr {
+    pub fn name(&self) -> &SmolStr {
         &self.name
     }
-    pub(crate) fn ptr(&self) -> LocalSyntaxPtr {
+    pub fn ptr(&self) -> LocalSyntaxPtr {
         self.ptr
     }
 }
@@ -249,18 +280,10 @@ fn compute_expr_scopes(expr: ast::Expr, scopes: &mut FnScopes, scope: ScopeId) {
     }
 }
 
-pub fn resolve_local_name<'a>(
-    name_ref: ast::NameRef,
-    scopes: &'a FnScopes,
-) -> Option<&'a ScopeEntry> {
-    let mut shadowed = FxHashSet::default();
-    let ret = scopes
-        .scope_chain(name_ref.syntax())
-        .flat_map(|scope| scopes.entries(scope).iter())
-        .filter(|entry| shadowed.insert(entry.name()))
-        .filter(|entry| entry.name() == &name_ref.text())
-        .nth(0);
-    ret
+#[derive(Debug)]
+pub struct ReferenceDescriptor {
+    pub range: TextRange,
+    pub name: String,
 }
 
 #[cfg(test)]
@@ -376,7 +399,7 @@ mod tests {
 
         let scopes = FnScopes::new(fn_def);
 
-        let local_name_entry = resolve_local_name(name_ref, &scopes).unwrap();
+        let local_name_entry = scopes.resolve_local_name(name_ref).unwrap();
         let local_name = local_name_entry.ptr().resolve(&file);
         let expected_name =
             find_node_at_offset::<ast::Name>(file.syntax(), expected_offset.into()).unwrap();
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
new file mode 100644
index 000000000..f13f0107e
--- /dev/null
+++ b/crates/ra_hir/src/lib.rs
@@ -0,0 +1,139 @@
+//! HIR (previsouly known as descriptors) provides a high-level OO acess to Rust
+//! code.
+//!
+//! The principal difference between HIR and syntax trees is that HIR is bound
+//! to a particular crate instance. That is, it has cfg flags and features
+//! applied. So, there relation between syntax and HIR is many-to-one.
+
+macro_rules! ctry {
+    ($expr:expr) => {
+        match $expr {
+            None => return Ok(None),
+            Some(it) => it,
+        }
+    };
+}
+
+pub mod db;
+mod query_definitions;
+mod function;
+mod module;
+mod path;
+mod arena;
+
+use std::ops::Index;
+
+use ra_syntax::{SyntaxNodeRef, SyntaxNode};
+use ra_db::{LocationIntener, SourceRootId, FileId, Cancelable};
+
+use crate::{
+    db::HirDatabase,
+    arena::{Arena, Id},
+};
+
+pub use self::{
+    path::{Path, PathKind},
+    module::{Module, ModuleId, Problem, nameres::ItemMap},
+    function::{Function, FnScopes},
+};
+
+pub use self::function::FnSignatureInfo;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct FnId(u32);
+ra_db::impl_numeric_id!(FnId);
+
+impl FnId {
+    pub fn from_loc(
+        db: &impl AsRef<LocationIntener<SourceItemId, FnId>>,
+        loc: &SourceItemId,
+    ) -> FnId {
+        db.as_ref().loc2id(loc)
+    }
+    pub fn loc(self, db: &impl AsRef<LocationIntener<SourceItemId, FnId>>) -> SourceItemId {
+        db.as_ref().id2loc(self)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct DefId(u32);
+ra_db::impl_numeric_id!(DefId);
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
+pub enum DefLoc {
+    Module {
+        id: ModuleId,
+        source_root: SourceRootId,
+    },
+    Item {
+        source_item_id: SourceItemId,
+    },
+}
+
+impl DefId {
+    pub fn loc(self, db: &impl AsRef<LocationIntener<DefLoc, DefId>>) -> DefLoc {
+        db.as_ref().id2loc(self)
+    }
+}
+
+impl DefLoc {
+    pub fn id(&self, db: &impl AsRef<LocationIntener<DefLoc, DefId>>) -> DefId {
+        db.as_ref().loc2id(&self)
+    }
+}
+
+pub enum Def {
+    Module(Module),
+    Item,
+}
+
+impl DefId {
+    pub fn resolve(self, db: &impl HirDatabase) -> Cancelable<Def> {
+        let loc = self.loc(db);
+        let res = match loc {
+            DefLoc::Module { id, source_root } => {
+                let descr = Module::new(db, source_root, id)?;
+                Def::Module(descr)
+            }
+            DefLoc::Item { .. } => Def::Item,
+        };
+        Ok(res)
+    }
+}
+
+/// Identifier of item within a specific file. This is stable over reparses, so
+/// it's OK to use it as a salsa key/value.
+pub(crate) type SourceFileItemId = Id<SyntaxNode>;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct SourceItemId {
+    file_id: FileId,
+    item_id: SourceFileItemId,
+}
+
+/// Maps item's `SyntaxNode`s to `SourceFileItemId` and back.
+#[derive(Debug, PartialEq, Eq, Default)]
+pub struct SourceFileItems {
+    arena: Arena<SyntaxNode>,
+}
+
+impl SourceFileItems {
+    fn alloc(&mut self, item: SyntaxNode) -> SourceFileItemId {
+        self.arena.alloc(item)
+    }
+    pub fn id_of(&self, item: SyntaxNodeRef) -> SourceFileItemId {
+        let (id, _item) = self
+            .arena
+            .iter()
+            .find(|(_id, i)| i.borrowed() == item)
+            .unwrap();
+        id
+    }
+}
+
+impl Index<SourceFileItemId> for SourceFileItems {
+    type Output = SyntaxNode;
+    fn index(&self, idx: SourceFileItemId) -> &SyntaxNode {
+        &self.arena[idx]
+    }
+}
diff --git a/crates/ra_analysis/src/descriptors/module/imp.rs b/crates/ra_hir/src/module/imp.rs
index 80892acb7..76ea129a7 100644
--- a/crates/ra_analysis/src/descriptors/module/imp.rs
+++ b/crates/ra_hir/src/module/imp.rs
@@ -6,21 +6,19 @@ use ra_syntax::{
 };
 use relative_path::RelativePathBuf;
 use rustc_hash::{FxHashMap, FxHashSet};
+use ra_db::{SourceRoot, SourceRootId, FileResolverImp, Cancelable, FileId,};
 
 use crate::{
-    db,
-    descriptors::DescriptorDatabase,
-    input::{SourceRoot, SourceRootId},
-    Cancelable, FileId, FileResolverImp,
+    HirDatabase,
 };
 
 use super::{
-    LinkData, LinkId, ModuleData, ModuleId, ModuleSource, ModuleSourceNode,
+    LinkData, LinkId, ModuleData, ModuleId, ModuleSource,
     ModuleTree, Problem,
 };
 
 #[derive(Clone, Hash, PartialEq, Eq, Debug)]
-pub(crate) enum Submodule {
+pub enum Submodule {
     Declaration(SmolStr),
     Definition(SmolStr, ModuleSource),
 }
@@ -34,39 +32,6 @@ impl Submodule {
     }
 }
 
-pub(crate) fn submodules(
-    db: &impl DescriptorDatabase,
-    source: ModuleSource,
-) -> Cancelable<Arc<Vec<Submodule>>> {
-    db::check_canceled(db)?;
-    let file_id = source.file_id();
-    let submodules = match source.resolve(db) {
-        ModuleSourceNode::SourceFile(it) => collect_submodules(file_id, it.borrowed()),
-        ModuleSourceNode::Module(it) => it
-            .borrowed()
-            .item_list()
-            .map(|it| collect_submodules(file_id, it))
-            .unwrap_or_else(Vec::new),
-    };
-    return Ok(Arc::new(submodules));
-
-    fn collect_submodules<'a>(
-        file_id: FileId,
-        root: impl ast::ModuleItemOwner<'a>,
-    ) -> Vec<Submodule> {
-        modules(root)
-            .map(|(name, m)| {
-                if m.has_semi() {
-                    Submodule::Declaration(name)
-                } else {
-                    let src = ModuleSource::new_inline(file_id, m);
-                    Submodule::Definition(name, src)
-                }
-            })
-            .collect()
-    }
-}
-
 pub(crate) fn modules<'a>(
     root: impl ast::ModuleItemOwner<'a>,
 ) -> impl Iterator<Item = (SmolStr, ast::Module<'a>)> {
@@ -82,16 +47,16 @@ pub(crate) fn modules<'a>(
 }
 
 pub(crate) fn module_tree(
-    db: &impl DescriptorDatabase,
+    db: &impl HirDatabase,
     source_root: SourceRootId,
 ) -> Cancelable<Arc<ModuleTree>> {
-    db::check_canceled(db)?;
+    db.check_canceled()?;
     let res = create_module_tree(db, source_root)?;
     Ok(Arc::new(res))
 }
 
 fn create_module_tree<'a>(
-    db: &impl DescriptorDatabase,
+    db: &impl HirDatabase,
     source_root: SourceRootId,
 ) -> Cancelable<ModuleTree> {
     let mut tree = ModuleTree::default();
@@ -121,7 +86,7 @@ fn create_module_tree<'a>(
 }
 
 fn build_subtree(
-    db: &impl DescriptorDatabase,
+    db: &impl HirDatabase,
     source_root: &SourceRoot,
     tree: &mut ModuleTree,
     visited: &mut FxHashSet<ModuleSource>,
@@ -135,7 +100,7 @@ fn build_subtree(
         parent,
         children: Vec::new(),
     });
-    for sub in db._submodules(source)?.iter() {
+    for sub in db.submodules(source)?.iter() {
         let link = tree.push_link(LinkData {
             name: sub.name().clone(),
             owner: id,
diff --git a/crates/ra_analysis/src/descriptors/module/mod.rs b/crates/ra_hir/src/module/mod.rs
index 78911d5d9..a011fd53e 100644
--- a/crates/ra_analysis/src/descriptors/module/mod.rs
+++ b/crates/ra_hir/src/module/mod.rs
@@ -10,65 +10,64 @@ use ra_syntax::{
     ast::{self, AstNode, NameOwner},
     SmolStr, SyntaxNode,
 };
+use ra_db::{SourceRootId, FileId, FilePosition, Cancelable};
 use relative_path::RelativePathBuf;
 
 use crate::{
-    db::SyntaxDatabase, syntax_ptr::SyntaxPtr, FileId, FilePosition, Cancelable,
-    descriptors::{Path, PathKind, DescriptorDatabase},
-    input::SourceRootId,
+    DefLoc, DefId, Path, PathKind, HirDatabase, SourceItemId,
     arena::{Arena, Id},
-    loc2id::{DefLoc, DefId},
 };
 
-pub(crate) use self::nameres::ModuleScope;
+pub use self::nameres::ModuleScope;
 
-/// `ModuleDescriptor` is API entry point to get all the information
+/// `Module` is API entry point to get all the information
 /// about a particular module.
 #[derive(Debug, Clone)]
-pub(crate) struct ModuleDescriptor {
+pub struct Module {
     tree: Arc<ModuleTree>,
     source_root_id: SourceRootId,
-    module_id: ModuleId,
+    //TODO: make private
+    pub module_id: ModuleId,
 }
 
-impl ModuleDescriptor {
-    /// Lookup `ModuleDescriptor` by `FileId`. Note that this is inherently
+impl Module {
+    /// Lookup `Module` by `FileId`. Note that this is inherently
     /// lossy transformation: in general, a single source might correspond to
     /// several modules.
     pub fn guess_from_file_id(
-        db: &impl DescriptorDatabase,
+        db: &impl HirDatabase,
         file_id: FileId,
-    ) -> Cancelable<Option<ModuleDescriptor>> {
-        ModuleDescriptor::guess_from_source(db, file_id, ModuleSource::SourceFile(file_id))
+    ) -> Cancelable<Option<Module>> {
+        Module::guess_from_source(db, file_id, ModuleSource::SourceFile(file_id))
     }
 
-    /// Lookup `ModuleDescriptor` by position in the source code. Note that this
+    /// Lookup `Module` by position in the source code. Note that this
     /// is inherently lossy transformation: in general, a single source might
     /// correspond to several modules.
     pub fn guess_from_position(
-        db: &impl DescriptorDatabase,
+        db: &impl HirDatabase,
         position: FilePosition,
-    ) -> Cancelable<Option<ModuleDescriptor>> {
-        let file = db.file_syntax(position.file_id);
+    ) -> Cancelable<Option<Module>> {
+        let file = db.source_file(position.file_id);
         let module_source = match find_node_at_offset::<ast::Module>(file.syntax(), position.offset)
         {
-            Some(m) if !m.has_semi() => ModuleSource::new_inline(position.file_id, m),
+            Some(m) if !m.has_semi() => ModuleSource::new_inline(db, position.file_id, m),
             _ => ModuleSource::SourceFile(position.file_id),
         };
-        ModuleDescriptor::guess_from_source(db, position.file_id, module_source)
+        Module::guess_from_source(db, position.file_id, module_source)
     }
 
     fn guess_from_source(
-        db: &impl DescriptorDatabase,
+        db: &impl HirDatabase,
         file_id: FileId,
         module_source: ModuleSource,
-    ) -> Cancelable<Option<ModuleDescriptor>> {
+    ) -> Cancelable<Option<Module>> {
         let source_root_id = db.file_source_root(file_id);
-        let module_tree = db._module_tree(source_root_id)?;
+        let module_tree = db.module_tree(source_root_id)?;
 
         let res = match module_tree.any_module_for_source(module_source) {
             None => None,
-            Some(module_id) => Some(ModuleDescriptor {
+            Some(module_id) => Some(Module {
                 tree: module_tree,
                 source_root_id,
                 module_id,
@@ -78,12 +77,12 @@ impl ModuleDescriptor {
     }
 
     pub(super) fn new(
-        db: &impl DescriptorDatabase,
+        db: &impl HirDatabase,
         source_root_id: SourceRootId,
         module_id: ModuleId,
-    ) -> Cancelable<ModuleDescriptor> {
-        let module_tree = db._module_tree(source_root_id)?;
-        let res = ModuleDescriptor {
+    ) -> Cancelable<Module> {
+        let module_tree = db.module_tree(source_root_id)?;
+        let res = Module {
             tree: module_tree,
             source_root_id,
             module_id,
@@ -93,10 +92,7 @@ impl ModuleDescriptor {
 
     /// Returns `mod foo;` or `mod foo {}` node whihc declared this module.
     /// Returns `None` for the root module
-    pub fn parent_link_source(
-        &self,
-        db: &impl DescriptorDatabase,
-    ) -> Option<(FileId, ast::ModuleNode)> {
+    pub fn parent_link_source(&self, db: &impl HirDatabase) -> Option<(FileId, ast::ModuleNode)> {
         let link = self.module_id.parent_link(&self.tree)?;
         let file_id = link.owner(&self.tree).source(&self.tree).file_id();
         let src = link.bind_source(&self.tree, db);
@@ -108,18 +104,18 @@ impl ModuleDescriptor {
     }
 
     /// Parent module. Returns `None` if this is a root module.
-    pub fn parent(&self) -> Option<ModuleDescriptor> {
+    pub fn parent(&self) -> Option<Module> {
         let parent_id = self.module_id.parent(&self.tree)?;
-        Some(ModuleDescriptor {
+        Some(Module {
             module_id: parent_id,
             ..self.clone()
         })
     }
 
     /// The root of the tree this module is part of
-    pub fn crate_root(&self) -> ModuleDescriptor {
+    pub fn crate_root(&self) -> Module {
         let root_id = self.module_id.crate_root(&self.tree);
-        ModuleDescriptor {
+        Module {
             module_id: root_id,
             ..self.clone()
         }
@@ -132,35 +128,31 @@ impl ModuleDescriptor {
         Some(link.name(&self.tree))
     }
 
-    pub fn def_id(&self, db: &impl DescriptorDatabase) -> DefId {
+    pub fn def_id(&self, db: &impl HirDatabase) -> DefId {
         let def_loc = DefLoc::Module {
             id: self.module_id,
             source_root: self.source_root_id,
         };
-        db.id_maps().def_id(def_loc)
+        def_loc.id(db)
     }
 
     /// Finds a child module with the specified name.
-    pub fn child(&self, name: &str) -> Option<ModuleDescriptor> {
+    pub fn child(&self, name: &str) -> Option<Module> {
         let child_id = self.module_id.child(&self.tree, name)?;
-        Some(ModuleDescriptor {
+        Some(Module {
             module_id: child_id,
             ..self.clone()
         })
     }
 
     /// Returns a `ModuleScope`: a set of items, visible in this module.
-    pub(crate) fn scope(&self, db: &impl DescriptorDatabase) -> Cancelable<ModuleScope> {
-        let item_map = db._item_map(self.source_root_id)?;
+    pub fn scope(&self, db: &impl HirDatabase) -> Cancelable<ModuleScope> {
+        let item_map = db.item_map(self.source_root_id)?;
         let res = item_map.per_module[&self.module_id].clone();
         Ok(res)
     }
 
-    pub(crate) fn resolve_path(
-        &self,
-        db: &impl DescriptorDatabase,
-        path: Path,
-    ) -> Cancelable<Option<DefId>> {
+    pub fn resolve_path(&self, db: &impl HirDatabase, path: Path) -> Cancelable<Option<DefId>> {
         let mut curr = match path.kind {
             PathKind::Crate => self.crate_root(),
             PathKind::Self_ | PathKind::Plain => self.clone(),
@@ -170,8 +162,8 @@ impl ModuleDescriptor {
 
         let segments = path.segments;
         for name in segments.iter() {
-            let module = match db.id_maps().def_loc(curr) {
-                DefLoc::Module { id, source_root } => ModuleDescriptor::new(db, source_root, id)?,
+            let module = match curr.loc(db) {
+                DefLoc::Module { id, source_root } => Module::new(db, source_root, id)?,
                 _ => return Ok(None),
             };
             let scope = module.scope(db)?;
@@ -180,7 +172,7 @@ impl ModuleDescriptor {
         Ok(Some(curr))
     }
 
-    pub fn problems(&self, db: &impl DescriptorDatabase) -> Vec<(SyntaxNode, Problem)> {
+    pub fn problems(&self, db: &impl HirDatabase) -> Vec<(SyntaxNode, Problem)> {
         self.module_id.problems(&self.tree, db)
     }
 }
@@ -193,13 +185,13 @@ impl ModuleDescriptor {
 /// (which can have multiple parents) to the precise world of modules (which
 /// always have one parent).
 #[derive(Default, Debug, PartialEq, Eq)]
-pub(crate) struct ModuleTree {
+pub struct ModuleTree {
     mods: Arena<ModuleData>,
     links: Arena<LinkData>,
 }
 
 impl ModuleTree {
-    fn modules<'a>(&'a self) -> impl Iterator<Item = ModuleId> + 'a {
+    pub(crate) fn modules<'a>(&'a self) -> impl Iterator<Item = ModuleId> + 'a {
         self.mods.iter().map(|(id, _)| id)
     }
 
@@ -219,20 +211,19 @@ impl ModuleTree {
 /// `ModuleSource` is the syntax tree element that produced this module:
 /// either a file, or an inlinde module.
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub(crate) enum ModuleSource {
+pub enum ModuleSource {
     SourceFile(FileId),
-    #[allow(dead_code)]
-    Module(SyntaxPtr),
+    Module(SourceItemId),
 }
 
 /// An owned syntax node for a module. Unlike `ModuleSource`,
 /// this holds onto the AST for the whole file.
-enum ModuleSourceNode {
+pub enum ModuleSourceNode {
     SourceFile(ast::SourceFileNode),
     Module(ast::ModuleNode),
 }
 
-pub(crate) type ModuleId = Id<ModuleData>;
+pub type ModuleId = Id<ModuleData>;
 type LinkId = Id<LinkData>;
 
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
@@ -247,7 +238,7 @@ pub enum Problem {
 }
 
 impl ModuleId {
-    fn source(self, tree: &ModuleTree) -> ModuleSource {
+    pub(crate) fn source(self, tree: &ModuleTree) -> ModuleSource {
         tree.mods[self].source
     }
     fn parent_link(self, tree: &ModuleTree) -> Option<LinkId> {
@@ -277,7 +268,7 @@ impl ModuleId {
             Some((link.name.clone(), module))
         })
     }
-    fn problems(self, tree: &ModuleTree, db: &impl SyntaxDatabase) -> Vec<(SyntaxNode, Problem)> {
+    fn problems(self, tree: &ModuleTree, db: &impl HirDatabase) -> Vec<(SyntaxNode, Problem)> {
         tree.mods[self]
             .children
             .iter()
@@ -298,7 +289,7 @@ impl LinkId {
     fn name(self, tree: &ModuleTree) -> SmolStr {
         tree.links[self].name.clone()
     }
-    fn bind_source<'a>(self, tree: &ModuleTree, db: &impl SyntaxDatabase) -> ast::ModuleNode {
+    fn bind_source<'a>(self, tree: &ModuleTree, db: &impl HirDatabase) -> ast::ModuleNode {
         let owner = self.owner(tree);
         match owner.source(tree).resolve(db) {
             ModuleSourceNode::SourceFile(root) => {
@@ -314,41 +305,47 @@ impl LinkId {
 }
 
 #[derive(Debug, PartialEq, Eq, Hash)]
-pub(crate) struct ModuleData {
+pub struct ModuleData {
     source: ModuleSource,
     parent: Option<LinkId>,
     children: Vec<LinkId>,
 }
 
 impl ModuleSource {
-    fn new_inline(file_id: FileId, module: ast::Module) -> ModuleSource {
+    pub(crate) fn new_inline(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        module: ast::Module,
+    ) -> ModuleSource {
         assert!(!module.has_semi());
-        let ptr = SyntaxPtr::new(file_id, module.syntax());
-        ModuleSource::Module(ptr)
+        let items = db.file_items(file_id);
+        let item_id = items.id_of(module.syntax());
+        let id = SourceItemId { file_id, item_id };
+        ModuleSource::Module(id)
     }
 
-    pub(crate) fn as_file(self) -> Option<FileId> {
+    pub fn as_file(self) -> Option<FileId> {
         match self {
             ModuleSource::SourceFile(f) => Some(f),
             ModuleSource::Module(..) => None,
         }
     }
 
-    pub(crate) fn file_id(self) -> FileId {
+    pub fn file_id(self) -> FileId {
         match self {
             ModuleSource::SourceFile(f) => f,
-            ModuleSource::Module(ptr) => ptr.file_id(),
+            ModuleSource::Module(source_item_id) => source_item_id.file_id,
         }
     }
 
-    fn resolve(self, db: &impl SyntaxDatabase) -> ModuleSourceNode {
+    pub fn resolve(self, db: &impl HirDatabase) -> ModuleSourceNode {
         match self {
             ModuleSource::SourceFile(file_id) => {
-                let syntax = db.file_syntax(file_id);
+                let syntax = db.source_file(file_id);
                 ModuleSourceNode::SourceFile(syntax.ast().owned())
             }
-            ModuleSource::Module(ptr) => {
-                let syntax = db.resolve_syntax_ptr(ptr);
+            ModuleSource::Module(item_id) => {
+                let syntax = db.file_item(item_id);
                 let syntax = syntax.borrowed();
                 let module = ast::Module::cast(syntax).unwrap();
                 ModuleSourceNode::Module(module.owned())
diff --git a/crates/ra_analysis/src/descriptors/module/nameres.rs b/crates/ra_hir/src/module/nameres.rs
index d2964f67f..837a8d5ae 100644
--- a/crates/ra_analysis/src/descriptors/module/nameres.rs
+++ b/crates/ra_hir/src/module/nameres.rs
@@ -16,101 +16,42 @@
 //! structure itself is modified.
 use std::{
     sync::Arc,
-    time::Instant,
-    ops::Index,
 };
 
 use rustc_hash::FxHashMap;
-
 use ra_syntax::{
-    SyntaxNode, SyntaxNodeRef, TextRange,
+    TextRange,
     SmolStr, SyntaxKind::{self, *},
-    ast::{self, ModuleItemOwner, AstNode}
+    ast::{self, AstNode}
 };
+use ra_db::SourceRootId;
 
 use crate::{
     Cancelable, FileId,
-    loc2id::{DefId, DefLoc},
-    descriptors::{
-        Path, PathKind,
-        DescriptorDatabase,
-        module::{ModuleId, ModuleTree, ModuleSourceNode},
-    },
-    input::SourceRootId,
-    arena::{Arena, Id}
+    DefId, DefLoc,
+    SourceItemId, SourceFileItemId, SourceFileItems,
+    Path, PathKind,
+    HirDatabase,
+    module::{ModuleId, ModuleTree},
 };
 
-/// Identifier of item within a specific file. This is stable over reparses, so
-/// it's OK to use it as a salsa key/value.
-pub(crate) type FileItemId = Id<SyntaxNode>;
-
-/// Maps item's `SyntaxNode`s to `FileItemId` and back.
-#[derive(Debug, PartialEq, Eq, Default)]
-pub(crate) struct FileItems {
-    arena: Arena<SyntaxNode>,
-}
-
-impl FileItems {
-    fn alloc(&mut self, item: SyntaxNode) -> FileItemId {
-        self.arena.alloc(item)
-    }
-    fn id_of(&self, item: SyntaxNodeRef) -> FileItemId {
-        let (id, _item) = self
-            .arena
-            .iter()
-            .find(|(_id, i)| i.borrowed() == item)
-            .unwrap();
-        id
-    }
-}
-
-impl Index<FileItemId> for FileItems {
-    type Output = SyntaxNode;
-    fn index(&self, idx: FileItemId) -> &SyntaxNode {
-        &self.arena[idx]
-    }
-}
-
-pub(crate) fn file_items(db: &impl DescriptorDatabase, file_id: FileId) -> Arc<FileItems> {
-    let source_file = db.file_syntax(file_id);
-    let source_file = source_file.borrowed();
-    let mut res = FileItems::default();
-    source_file
-        .syntax()
-        .descendants()
-        .filter_map(ast::ModuleItem::cast)
-        .map(|it| it.syntax().owned())
-        .for_each(|it| {
-            res.alloc(it);
-        });
-    Arc::new(res)
-}
-
-pub(crate) fn file_item(
-    db: &impl DescriptorDatabase,
-    file_id: FileId,
-    file_item_id: FileItemId,
-) -> SyntaxNode {
-    db._file_items(file_id)[file_item_id].clone()
-}
-
 /// Item map is the result of the name resolution. Item map contains, for each
 /// module, the set of visible items.
 #[derive(Default, Debug, PartialEq, Eq)]
-pub(crate) struct ItemMap {
-    pub(crate) per_module: FxHashMap<ModuleId, ModuleScope>,
+pub struct ItemMap {
+    pub per_module: FxHashMap<ModuleId, ModuleScope>,
 }
 
 #[derive(Debug, Default, PartialEq, Eq, Clone)]
-pub(crate) struct ModuleScope {
-    items: FxHashMap<SmolStr, Resolution>,
+pub struct ModuleScope {
+    pub items: FxHashMap<SmolStr, Resolution>,
 }
 
 impl ModuleScope {
-    pub(crate) fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a SmolStr, &Resolution)> + 'a {
+    pub fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a SmolStr, &Resolution)> + 'a {
         self.items.iter()
     }
-    pub(crate) fn get(&self, name: &SmolStr) -> Option<&Resolution> {
+    pub fn get(&self, name: &SmolStr) -> Option<&Resolution> {
         self.items.get(name)
     }
 }
@@ -122,14 +63,14 @@ impl ModuleScope {
 /// recomputing name res: if `InputModuleItems` are the same, we can avoid
 /// running name resolution.
 #[derive(Debug, Default, PartialEq, Eq)]
-pub(crate) struct InputModuleItems {
+pub struct InputModuleItems {
     items: Vec<ModuleItem>,
     imports: Vec<Import>,
 }
 
 #[derive(Debug, PartialEq, Eq)]
 struct ModuleItem {
-    id: FileItemId,
+    id: SourceFileItemId,
     name: SmolStr,
     kind: SyntaxKind,
     vis: Vis,
@@ -148,14 +89,18 @@ struct Import {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) struct NamedImport {
-    file_item_id: FileItemId,
-    relative_range: TextRange,
+pub struct NamedImport {
+    pub file_item_id: SourceFileItemId,
+    pub relative_range: TextRange,
 }
 
 impl NamedImport {
-    pub(crate) fn range(&self, db: &impl DescriptorDatabase, file_id: FileId) -> TextRange {
-        let syntax = db._file_item(file_id, self.file_item_id);
+    pub fn range(&self, db: &impl HirDatabase, file_id: FileId) -> TextRange {
+        let source_item_id = SourceItemId {
+            file_id,
+            item_id: self.file_item_id,
+        };
+        let syntax = db.file_item(source_item_id);
         let offset = syntax.borrowed().range().start();
         self.relative_range + offset
     }
@@ -167,66 +112,14 @@ enum ImportKind {
     Named(NamedImport),
 }
 
-pub(crate) fn input_module_items(
-    db: &impl DescriptorDatabase,
-    source_root: SourceRootId,
-    module_id: ModuleId,
-) -> Cancelable<Arc<InputModuleItems>> {
-    let module_tree = db._module_tree(source_root)?;
-    let source = module_id.source(&module_tree);
-    let file_items = db._file_items(source.file_id());
-    let res = match source.resolve(db) {
-        ModuleSourceNode::SourceFile(it) => {
-            let items = it.borrowed().items();
-            InputModuleItems::new(&file_items, items)
-        }
-        ModuleSourceNode::Module(it) => {
-            let items = it
-                .borrowed()
-                .item_list()
-                .into_iter()
-                .flat_map(|it| it.items());
-            InputModuleItems::new(&file_items, items)
-        }
-    };
-    Ok(Arc::new(res))
-}
-
-pub(crate) fn item_map(
-    db: &impl DescriptorDatabase,
-    source_root: SourceRootId,
-) -> Cancelable<Arc<ItemMap>> {
-    let start = Instant::now();
-    let module_tree = db._module_tree(source_root)?;
-    let input = module_tree
-        .modules()
-        .map(|id| {
-            let items = db._input_module_items(source_root, id)?;
-            Ok((id, items))
-        })
-        .collect::<Cancelable<FxHashMap<_, _>>>()?;
-    let mut resolver = Resolver {
-        db: db,
-        input: &input,
-        source_root,
-        module_tree,
-        result: ItemMap::default(),
-    };
-    resolver.resolve()?;
-    let res = resolver.result;
-    let elapsed = start.elapsed();
-    log::info!("item_map: {:?}", elapsed);
-    Ok(Arc::new(res))
-}
-
 /// Resolution is basically `DefId` atm, but it should account for stuff like
 /// multiple namespaces, ambiguity and errors.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) struct Resolution {
+pub struct Resolution {
     /// None for unresolved
-    pub(crate) def_id: Option<DefId>,
+    pub def_id: Option<DefId>,
     /// ident by whitch this is imported into local scope.
-    pub(crate) import: Option<NamedImport>,
+    pub import: Option<NamedImport>,
 }
 
 // #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -242,8 +135,8 @@ pub(crate) struct Resolution {
 // }
 
 impl InputModuleItems {
-    fn new<'a>(
-        file_items: &FileItems,
+    pub(crate) fn new<'a>(
+        file_items: &SourceFileItems,
         items: impl Iterator<Item = ast::ModuleItem<'a>>,
     ) -> InputModuleItems {
         let mut res = InputModuleItems::default();
@@ -253,7 +146,7 @@ impl InputModuleItems {
         res
     }
 
-    fn add_item(&mut self, file_items: &FileItems, item: ast::ModuleItem) -> Option<()> {
+    fn add_item(&mut self, file_items: &SourceFileItems, item: ast::ModuleItem) -> Option<()> {
         match item {
             ast::ModuleItem::StructDef(it) => self.items.push(ModuleItem::new(file_items, it)?),
             ast::ModuleItem::EnumDef(it) => self.items.push(ModuleItem::new(file_items, it)?),
@@ -274,7 +167,7 @@ impl InputModuleItems {
         Some(())
     }
 
-    fn add_use_item(&mut self, file_items: &FileItems, item: ast::UseItem) {
+    fn add_use_item(&mut self, file_items: &SourceFileItems, item: ast::UseItem) {
         let file_item_id = file_items.id_of(item.syntax());
         let start_offset = item.syntax().range().start();
         Path::expand_use_item(item, |path, range| {
@@ -291,7 +184,7 @@ impl InputModuleItems {
 }
 
 impl ModuleItem {
-    fn new<'a>(file_items: &FileItems, item: impl ast::NameOwner<'a>) -> Option<ModuleItem> {
+    fn new<'a>(file_items: &SourceFileItems, item: impl ast::NameOwner<'a>) -> Option<ModuleItem> {
         let name = item.name()?.text();
         let kind = item.syntax().kind();
         let vis = Vis::Other;
@@ -306,28 +199,28 @@ impl ModuleItem {
     }
 }
 
-struct Resolver<'a, DB> {
-    db: &'a DB,
-    input: &'a FxHashMap<ModuleId, Arc<InputModuleItems>>,
-    source_root: SourceRootId,
-    module_tree: Arc<ModuleTree>,
-    result: ItemMap,
+pub(crate) struct Resolver<'a, DB> {
+    pub db: &'a DB,
+    pub input: &'a FxHashMap<ModuleId, Arc<InputModuleItems>>,
+    pub source_root: SourceRootId,
+    pub module_tree: Arc<ModuleTree>,
+    pub result: ItemMap,
 }
 
 impl<'a, DB> Resolver<'a, DB>
 where
-    DB: DescriptorDatabase,
+    DB: HirDatabase,
 {
-    fn resolve(&mut self) -> Cancelable<()> {
+    pub(crate) fn resolve(mut self) -> Cancelable<ItemMap> {
         for (&module_id, items) in self.input.iter() {
             self.populate_module(module_id, items)
         }
 
         for &module_id in self.input.keys() {
-            crate::db::check_canceled(self.db)?;
+            self.db.check_canceled()?;
             self.resolve_imports(module_id);
         }
-        Ok(())
+        Ok(self.result)
     }
 
     fn populate_module(&mut self, module_id: ModuleId, input: &InputModuleItems) {
@@ -355,10 +248,12 @@ where
                 continue;
             }
             let def_loc = DefLoc::Item {
-                file_id,
-                id: item.id,
+                source_item_id: SourceItemId {
+                    file_id,
+                    item_id: item.id,
+                },
             };
-            let def_id = self.db.id_maps().def_id(def_loc);
+            let def_id = def_loc.id(self.db);
             let resolution = Resolution {
                 def_id: Some(def_id),
                 import: None,
@@ -371,7 +266,7 @@ where
                 id: mod_id,
                 source_root: self.source_root,
             };
-            let def_id = self.db.id_maps().def_id(def_loc);
+            let def_id = def_loc.id(self.db);
             let resolution = Resolution {
                 def_id: Some(def_id),
                 import: None,
@@ -420,7 +315,7 @@ where
             };
 
             if !is_last {
-                curr = match self.db.id_maps().def_loc(def_id) {
+                curr = match def_id.loc(self.db) {
                     DefLoc::Module { id, .. } => id,
                     _ => return,
                 }
@@ -441,109 +336,3 @@ where
         f(module_items)
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use crate::{
-        AnalysisChange,
-        mock_analysis::{MockAnalysis, analysis_and_position},
-        descriptors::{DescriptorDatabase, module::ModuleDescriptor},
-        input::FilesDatabase,
-};
-    use super::*;
-
-    fn item_map(fixture: &str) -> (Arc<ItemMap>, ModuleId) {
-        let (analysis, pos) = analysis_and_position(fixture);
-        let db = analysis.imp.db;
-        let source_root = db.file_source_root(pos.file_id);
-        let descr = ModuleDescriptor::guess_from_position(&*db, pos)
-            .unwrap()
-            .unwrap();
-        let module_id = descr.module_id;
-        (db._item_map(source_root).unwrap(), module_id)
-    }
-
-    #[test]
-    fn test_item_map() {
-        let (item_map, module_id) = item_map(
-            "
-            //- /lib.rs
-            mod foo;
-
-            use crate::foo::bar::Baz;
-            <|>
-
-            //- /foo/mod.rs
-            pub mod bar;
-
-            //- /foo/bar.rs
-            pub struct Baz;
-        ",
-        );
-        let name = SmolStr::from("Baz");
-        let resolution = &item_map.per_module[&module_id].items[&name];
-        assert!(resolution.def_id.is_some());
-    }
-
-    #[test]
-    fn typing_inside_a_function_should_not_invalidate_item_map() {
-        let mock_analysis = MockAnalysis::with_files(
-            "
-            //- /lib.rs
-            mod foo;
-
-            use crate::foo::bar::Baz;
-
-            fn foo() -> i32 {
-                1 + 1
-            }
-            //- /foo/mod.rs
-            pub mod bar;
-
-            //- /foo/bar.rs
-            pub struct Baz;
-        ",
-        );
-
-        let file_id = mock_analysis.id_of("/lib.rs");
-        let mut host = mock_analysis.analysis_host();
-
-        let source_root = host.analysis().imp.db.file_source_root(file_id);
-
-        {
-            let db = host.analysis().imp.db;
-            let events = db.log_executed(|| {
-                db._item_map(source_root).unwrap();
-            });
-            assert!(format!("{:?}", events).contains("_item_map"))
-        }
-
-        let mut change = AnalysisChange::new();
-
-        change.change_file(
-            file_id,
-            "
-            mod foo;
-
-            use crate::foo::bar::Baz;
-
-            fn foo() -> i32 { 92 }
-        "
-            .to_string(),
-        );
-
-        host.apply_change(change);
-
-        {
-            let db = host.analysis().imp.db;
-            let events = db.log_executed(|| {
-                db._item_map(source_root).unwrap();
-            });
-            assert!(
-                !format!("{:?}", events).contains("_item_map"),
-                "{:#?}",
-                events
-            )
-        }
-    }
-}
diff --git a/crates/ra_analysis/src/descriptors/path.rs b/crates/ra_hir/src/path.rs
index 8279daf4b..4a2e427cd 100644
--- a/crates/ra_analysis/src/descriptors/path.rs
+++ b/crates/ra_hir/src/path.rs
@@ -1,13 +1,13 @@
 use ra_syntax::{SmolStr, ast, AstNode, TextRange};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) struct Path {
-    pub(crate) kind: PathKind,
-    pub(crate) segments: Vec<SmolStr>,
+pub struct Path {
+    pub kind: PathKind,
+    pub segments: Vec<SmolStr>,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) enum PathKind {
+pub enum PathKind {
     Plain,
     Self_,
     Super,
@@ -16,14 +16,14 @@ pub(crate) enum PathKind {
 
 impl Path {
     /// Calls `cb` with all paths, represented by this use item.
-    pub(crate) fn expand_use_item(item: ast::UseItem, mut cb: impl FnMut(Path, Option<TextRange>)) {
+    pub fn expand_use_item(item: ast::UseItem, mut cb: impl FnMut(Path, Option<TextRange>)) {
         if let Some(tree) = item.use_tree() {
             expand_use_tree(None, tree, &mut cb);
         }
     }
 
     /// Converts an `ast::Path` to `Path`. Works with use trees.
-    pub(crate) fn from_ast(mut path: ast::Path) -> Option<Path> {
+    pub fn from_ast(mut path: ast::Path) -> Option<Path> {
         let mut kind = PathKind::Plain;
         let mut segments = Vec::new();
         loop {
@@ -64,7 +64,7 @@ impl Path {
     }
 
     /// `true` is this path is a single identifier, like `foo`
-    pub(crate) fn is_ident(&self) -> bool {
+    pub fn is_ident(&self) -> bool {
         self.kind == PathKind::Plain && self.segments.len() == 1
     }
 }
diff --git a/crates/ra_hir/src/query_definitions.rs b/crates/ra_hir/src/query_definitions.rs
new file mode 100644
index 000000000..6f602878c
--- /dev/null
+++ b/crates/ra_hir/src/query_definitions.rs
@@ -0,0 +1,154 @@
+use std::{
+    sync::Arc,
+    time::Instant,
+};
+
+use rustc_hash::FxHashMap;
+use ra_syntax::{
+    AstNode,  SyntaxNode, SmolStr,
+    ast::{self, FnDef, FnDefNode, NameOwner, ModuleItemOwner}
+};
+use ra_db::{SourceRootId, FileId, Cancelable,};
+
+use crate::{
+        FnId,
+        SourceFileItems, SourceItemId,
+        db::HirDatabase,
+        function::FnScopes,
+        module::{
+            ModuleSource, ModuleSourceNode, ModuleId,
+            imp::Submodule,
+            nameres::{InputModuleItems, ItemMap, Resolver},
+        },
+};
+
+/// Resolve `FnId` to the corresponding `SyntaxNode`
+pub(super) fn fn_syntax(db: &impl HirDatabase, fn_id: FnId) -> FnDefNode {
+    let item_id = fn_id.loc(db);
+    let syntax = db.file_item(item_id);
+    FnDef::cast(syntax.borrowed()).unwrap().owned()
+}
+
+pub(super) fn fn_scopes(db: &impl HirDatabase, fn_id: FnId) -> Arc<FnScopes> {
+    let syntax = db.fn_syntax(fn_id);
+    let res = FnScopes::new(syntax.borrowed());
+    Arc::new(res)
+}
+
+pub(super) fn file_items(db: &impl HirDatabase, file_id: FileId) -> Arc<SourceFileItems> {
+    let source_file = db.source_file(file_id);
+    let source_file = source_file.borrowed();
+    let mut res = SourceFileItems::default();
+    source_file
+        .syntax()
+        .descendants()
+        .filter_map(ast::ModuleItem::cast)
+        .map(|it| it.syntax().owned())
+        .for_each(|it| {
+            res.alloc(it);
+        });
+    Arc::new(res)
+}
+
+pub(super) fn file_item(db: &impl HirDatabase, source_item_id: SourceItemId) -> SyntaxNode {
+    db.file_items(source_item_id.file_id)[source_item_id.item_id].clone()
+}
+
+pub(crate) fn submodules(
+    db: &impl HirDatabase,
+    source: ModuleSource,
+) -> Cancelable<Arc<Vec<Submodule>>> {
+    db.check_canceled()?;
+    let file_id = source.file_id();
+    let submodules = match source.resolve(db) {
+        ModuleSourceNode::SourceFile(it) => collect_submodules(db, file_id, it.borrowed()),
+        ModuleSourceNode::Module(it) => it
+            .borrowed()
+            .item_list()
+            .map(|it| collect_submodules(db, file_id, it))
+            .unwrap_or_else(Vec::new),
+    };
+    return Ok(Arc::new(submodules));
+
+    fn collect_submodules<'a>(
+        db: &impl HirDatabase,
+        file_id: FileId,
+        root: impl ast::ModuleItemOwner<'a>,
+    ) -> Vec<Submodule> {
+        modules(root)
+            .map(|(name, m)| {
+                if m.has_semi() {
+                    Submodule::Declaration(name)
+                } else {
+                    let src = ModuleSource::new_inline(db, file_id, m);
+                    Submodule::Definition(name, src)
+                }
+            })
+            .collect()
+    }
+}
+
+pub(crate) fn modules<'a>(
+    root: impl ast::ModuleItemOwner<'a>,
+) -> impl Iterator<Item = (SmolStr, ast::Module<'a>)> {
+    root.items()
+        .filter_map(|item| match item {
+            ast::ModuleItem::Module(m) => Some(m),
+            _ => None,
+        })
+        .filter_map(|module| {
+            let name = module.name()?.text();
+            Some((name, module))
+        })
+}
+
+pub(super) fn input_module_items(
+    db: &impl HirDatabase,
+    source_root: SourceRootId,
+    module_id: ModuleId,
+) -> Cancelable<Arc<InputModuleItems>> {
+    let module_tree = db.module_tree(source_root)?;
+    let source = module_id.source(&module_tree);
+    let file_items = db.file_items(source.file_id());
+    let res = match source.resolve(db) {
+        ModuleSourceNode::SourceFile(it) => {
+            let items = it.borrowed().items();
+            InputModuleItems::new(&file_items, items)
+        }
+        ModuleSourceNode::Module(it) => {
+            let items = it
+                .borrowed()
+                .item_list()
+                .into_iter()
+                .flat_map(|it| it.items());
+            InputModuleItems::new(&file_items, items)
+        }
+    };
+    Ok(Arc::new(res))
+}
+
+pub(super) fn item_map(
+    db: &impl HirDatabase,
+    source_root: SourceRootId,
+) -> Cancelable<Arc<ItemMap>> {
+    let start = Instant::now();
+    let module_tree = db.module_tree(source_root)?;
+    let input = module_tree
+        .modules()
+        .map(|id| {
+            let items = db.input_module_items(source_root, id)?;
+            Ok((id, items))
+        })
+        .collect::<Cancelable<FxHashMap<_, _>>>()?;
+    let resolver = Resolver {
+        db: db,
+        input: &input,
+        source_root,
+        module_tree,
+        result: ItemMap::default(),
+    };
+    let res = resolver.resolve()?;
+    let elapsed = start.elapsed();
+    log::info!("item_map: {:?}", elapsed);
+    Ok(Arc::new(res))
+}
diff --git a/crates/ra_lsp_server/src/server_world.rs b/crates/ra_lsp_server/src/server_world.rs
index 3e7670fcc..12faeb93a 100644
--- a/crates/ra_lsp_server/src/server_world.rs
+++ b/crates/ra_lsp_server/src/server_world.rs
@@ -140,7 +140,7 @@ impl ServerWorldState {
         Ok(file_id)
     }
     pub fn set_workspaces(&mut self, ws: Vec<CargoWorkspace>) {
-        let mut crate_graph = CrateGraph::new();
+        let mut crate_graph = CrateGraph::default();
         ws.iter()
             .flat_map(|ws| {
                 ws.packages()