Merge #1362

1362: Introduce AST database r=matklad a=matklad

The idea here is to separate fragile bits which look into the syntax directly from robust bits which are safe across reparses. This uses the new `salsa::requires` featue

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

15 files changed, 177 insertions, 95 deletions

diff --git a/crates/ra_hir/src/adt.rs b/crates/ra_hir/src/adt.rs
index 5e5905f15..45a12dd4d 100644
--- a/crates/ra_hir/src/adt.rs
+++ b/crates/ra_hir/src/adt.rs
@@ -10,7 +10,7 @@ use ra_syntax::{
 };
 
 use crate::{
-    Name, AsName, Struct, Union, Enum, EnumVariant, Crate,
+    Name, AsName, Struct, Union, Enum, EnumVariant, Crate, AstDatabase,
     HirDatabase, HirFileId, StructField, FieldSource,
     type_ref::TypeRef, DefDatabase,
 };
@@ -55,7 +55,10 @@ impl StructData {
         StructData { name, variant_data }
     }
 
-    pub(crate) fn struct_data_query(db: &impl DefDatabase, struct_: Struct) -> Arc<StructData> {
+    pub(crate) fn struct_data_query(
+        db: &(impl DefDatabase + AstDatabase),
+        struct_: Struct,
+    ) -> Arc<StructData> {
         let (_, struct_def) = struct_.source(db);
         Arc::new(StructData::new(&*struct_def))
     }
@@ -68,7 +71,7 @@ fn variants(enum_def: &ast::EnumDef) -> impl Iterator<Item = &ast::EnumVariant>
 impl EnumVariant {
     pub(crate) fn source_impl(
         &self,
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
     ) -> (HirFileId, TreeArc<ast::EnumVariant>) {
         let (file_id, enum_def) = self.parent.source(db);
         let var = variants(&*enum_def)
@@ -91,7 +94,7 @@ pub struct EnumData {
 }
 
 impl EnumData {
-    pub(crate) fn enum_data_query(db: &impl DefDatabase, e: Enum) -> Arc<EnumData> {
+    pub(crate) fn enum_data_query(db: &(impl DefDatabase + AstDatabase), e: Enum) -> Arc<EnumData> {
         let (_file_id, enum_def) = e.source(db);
         let name = enum_def.name().map(|n| n.as_name());
         let variants = variants(&*enum_def)
@@ -198,7 +201,10 @@ impl VariantDef {
 }
 
 impl StructField {
-    pub(crate) fn source_impl(&self, db: &impl DefDatabase) -> (HirFileId, FieldSource) {
+    pub(crate) fn source_impl(
+        &self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, FieldSource) {
         let var_data = self.parent.variant_data(db);
         let fields = var_data.fields().unwrap();
         let ss;
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index e3c765674..9c02b3995 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -5,7 +5,7 @@ use ra_syntax::{ast::{self, NameOwner, TypeAscriptionOwner}, TreeArc};
 
 use crate::{
     Name, AsName, AstId, Ty, HirFileId, Either, KnownName,
-    HirDatabase, DefDatabase,
+    HirDatabase, DefDatabase, AstDatabase,
     type_ref::TypeRef,
     nameres::{ModuleScope, Namespace, ImportId, CrateModuleId},
     expr::{Body, BodySourceMap, validation::ExprValidator},
@@ -147,7 +147,7 @@ pub enum ModuleSource {
 
 impl ModuleSource {
     pub(crate) fn new(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         file_id: Option<FileId>,
         decl_id: Option<AstId<ast::Module>>,
     ) -> ModuleSource {
@@ -168,7 +168,7 @@ impl ModuleSource {
 
 impl Module {
     /// Name of this module.
-    pub fn name(self, db: &impl HirDatabase) -> Option<Name> {
+    pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
         let def_map = db.crate_def_map(self.krate);
         let parent = def_map[self.module_id].parent?;
         def_map[parent].children.iter().find_map(|(name, module_id)| {
@@ -181,7 +181,10 @@ impl Module {
     }
 
     /// Returns a node which defines this module. That is, a file or a `mod foo {}` with items.
-    pub fn definition_source(self, db: &impl DefDatabase) -> (HirFileId, ModuleSource) {
+    pub fn definition_source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, ModuleSource) {
         let def_map = db.crate_def_map(self.krate);
         let decl_id = def_map[self.module_id].declaration;
         let file_id = def_map[self.module_id].definition;
@@ -340,7 +343,7 @@ impl StructField {
         self.parent.variant_data(db).fields().unwrap()[self.id].name.clone()
     }
 
-    pub fn source(&self, db: &impl DefDatabase) -> (HirFileId, FieldSource) {
+    pub fn source(&self, db: &(impl DefDatabase + AstDatabase)) -> (HirFileId, FieldSource) {
         self.source_impl(db)
     }
 
@@ -368,7 +371,10 @@ pub struct Struct {
 }
 
 impl Struct {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::StructDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::StructDef>) {
         self.id.source(db)
     }
 
@@ -376,7 +382,7 @@ impl Struct {
         self.id.module(db)
     }
 
-    pub fn name(self, db: &impl HirDatabase) -> Option<Name> {
+    pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
         db.struct_data(self).name.clone()
     }
 
@@ -432,11 +438,14 @@ pub struct Union {
 }
 
 impl Union {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::StructDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::StructDef>) {
         self.id.source(db)
     }
 
-    pub fn name(self, db: &impl HirDatabase) -> Option<Name> {
+    pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
         db.struct_data(Struct { id: self.id }).name.clone()
     }
 
@@ -468,7 +477,10 @@ pub struct Enum {
 }
 
 impl Enum {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::EnumDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::EnumDef>) {
         self.id.source(db)
     }
 
@@ -476,7 +488,7 @@ impl Enum {
         self.id.module(db)
     }
 
-    pub fn name(self, db: &impl HirDatabase) -> Option<Name> {
+    pub fn name(self, db: &impl DefDatabase) -> Option<Name> {
         db.enum_data(self).name.clone()
     }
 
@@ -521,7 +533,10 @@ pub struct EnumVariant {
 }
 
 impl EnumVariant {
-    pub fn source(&self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::EnumVariant>) {
+    pub fn source(
+        &self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::EnumVariant>) {
         self.source_impl(db)
     }
     pub fn module(&self, db: &impl HirDatabase) -> Module {
@@ -610,7 +625,10 @@ pub struct FnSignature {
 }
 
 impl FnSignature {
-    pub(crate) fn fn_signature_query(db: &impl DefDatabase, func: Function) -> Arc<FnSignature> {
+    pub(crate) fn fn_signature_query(
+        db: &(impl DefDatabase + AstDatabase),
+        func: Function,
+    ) -> Arc<FnSignature> {
         let (_, node) = func.source(db);
         let name = node.name().map(|n| n.as_name()).unwrap_or_else(Name::missing);
         let mut params = Vec::new();
@@ -668,7 +686,7 @@ impl FnSignature {
 }
 
 impl Function {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::FnDef>) {
+    pub fn source(self, db: &(impl DefDatabase + AstDatabase)) -> (HirFileId, TreeArc<ast::FnDef>) {
         self.id.source(db)
     }
 
@@ -752,7 +770,10 @@ pub struct Const {
 }
 
 impl Const {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::ConstDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::ConstDef>) {
         self.id.source(db)
     }
 
@@ -809,7 +830,7 @@ impl ConstSignature {
     }
 
     pub(crate) fn const_signature_query(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         konst: Const,
     ) -> Arc<ConstSignature> {
         let (_, node) = konst.source(db);
@@ -817,7 +838,7 @@ impl ConstSignature {
     }
 
     pub(crate) fn static_signature_query(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         konst: Static,
     ) -> Arc<ConstSignature> {
         let (_, node) = konst.source(db);
@@ -838,7 +859,10 @@ pub struct Static {
 }
 
 impl Static {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::StaticDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::StaticDef>) {
         self.id.source(db)
     }
 
@@ -873,7 +897,10 @@ pub struct Trait {
 }
 
 impl Trait {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::TraitDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::TraitDef>) {
         self.id.source(db)
     }
 
@@ -922,7 +949,10 @@ pub struct TypeAlias {
 }
 
 impl TypeAlias {
-    pub fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::TypeAliasDef>) {
+    pub fn source(
+        self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::TypeAliasDef>) {
         self.id.source(db)
     }
 
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index e8b4f0ddc..872103219 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -21,10 +21,35 @@ use crate::{
     lang_item::{LangItems, LangItemTarget},
 };
 
-#[salsa::query_group(DefDatabaseStorage)]
-pub trait DefDatabase: SourceDatabase {
+// This database has access to source code, so queries here are not really
+// incremental.
+#[salsa::query_group(AstDatabaseStorage)]
+pub trait AstDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_macro(&self, macro_call: MacroCallLoc) -> ids::MacroCallId;
+
+    #[salsa::invoke(crate::source_id::AstIdMap::ast_id_map_query)]
+    fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
+    #[salsa::transparent]
+    #[salsa::invoke(crate::source_id::AstIdMap::file_item_query)]
+    fn ast_id_to_node(&self, file_id: HirFileId, ast_id: ErasedFileAstId) -> TreeArc<SyntaxNode>;
+    #[salsa::invoke(crate::ids::HirFileId::parse_or_expand_query)]
+    fn parse_or_expand(&self, file_id: HirFileId) -> Option<TreeArc<SyntaxNode>>;
+
+    #[salsa::invoke(crate::ids::macro_def_query)]
+    fn macro_def(&self, macro_id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
+
+    #[salsa::invoke(crate::ids::macro_arg_query)]
+    fn macro_arg(&self, macro_call: ids::MacroCallId) -> Option<Arc<tt::Subtree>>;
+
+    #[salsa::invoke(crate::ids::macro_expand_query)]
+    fn macro_expand(&self, macro_call: ids::MacroCallId) -> Result<Arc<tt::Subtree>, String>;
+}
+
+// This database uses `AstDatabase` internally,
+#[salsa::query_group(DefDatabaseStorage)]
+#[salsa::requires(AstDatabase)]
+pub trait DefDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_function(&self, loc: ids::ItemLoc<ast::FnDef>) -> ids::FunctionId;
     #[salsa::interned]
@@ -46,18 +71,6 @@ pub trait DefDatabase: SourceDatabase {
     #[salsa::interned]
     fn intern_impl_block(&self, impl_block: ImplBlock) -> ids::GlobalImplId;
 
-    #[salsa::invoke(crate::ids::macro_def_query)]
-    fn macro_def(&self, macro_id: MacroDefId) -> Option<Arc<mbe::MacroRules>>;
-
-    #[salsa::invoke(crate::ids::macro_arg_query)]
-    fn macro_arg(&self, macro_call: ids::MacroCallId) -> Option<Arc<tt::Subtree>>;
-
-    #[salsa::invoke(crate::ids::macro_expand_query)]
-    fn macro_expand(&self, macro_call: ids::MacroCallId) -> Result<Arc<tt::Subtree>, String>;
-
-    #[salsa::invoke(crate::ids::HirFileId::parse_or_expand_query)]
-    fn parse_or_expand(&self, file_id: HirFileId) -> Option<TreeArc<SyntaxNode>>;
-
     #[salsa::invoke(crate::adt::StructData::struct_data_query)]
     fn struct_data(&self, s: Struct) -> Arc<StructData>;
 
@@ -70,13 +83,6 @@ pub trait DefDatabase: SourceDatabase {
     #[salsa::invoke(crate::traits::TraitItemsIndex::trait_items_index)]
     fn trait_items_index(&self, module: Module) -> crate::traits::TraitItemsIndex;
 
-    #[salsa::invoke(crate::source_id::AstIdMap::ast_id_map_query)]
-    fn ast_id_map(&self, file_id: HirFileId) -> Arc<AstIdMap>;
-
-    #[salsa::invoke(crate::source_id::AstIdMap::file_item_query)]
-    #[salsa::transparent]
-    fn ast_id_to_node(&self, file_id: HirFileId, ast_id: ErasedFileAstId) -> TreeArc<SyntaxNode>;
-
     #[salsa::invoke(RawItems::raw_items_query)]
     fn raw_items(&self, file_id: HirFileId) -> Arc<RawItems>;
 
@@ -121,7 +127,7 @@ pub trait DefDatabase: SourceDatabase {
 }
 
 #[salsa::query_group(HirDatabaseStorage)]
-pub trait HirDatabase: DefDatabase {
+pub trait HirDatabase: DefDatabase + AstDatabase {
     #[salsa::invoke(ExprScopes::expr_scopes_query)]
     fn expr_scopes(&self, def: DefWithBody) -> Arc<ExprScopes>;
 
diff --git a/crates/ra_hir/src/generics.rs b/crates/ra_hir/src/generics.rs
index 8effbbe35..b6c5e18d3 100644
--- a/crates/ra_hir/src/generics.rs
+++ b/crates/ra_hir/src/generics.rs
@@ -8,7 +8,7 @@ use std::sync::Arc;
 use ra_syntax::ast::{self, NameOwner, TypeParamsOwner, TypeBoundsOwner, DefaultTypeParamOwner};
 
 use crate::{
-    db::{ HirDatabase, DefDatabase},
+    db::{HirDatabase, DefDatabase, AstDatabase},
     Name, AsName, Function, Struct, Union, Enum, Trait, TypeAlias, ImplBlock, Container, path::Path, type_ref::TypeRef, AdtDef
 };
 
@@ -52,7 +52,7 @@ impl_froms!(GenericDef: Function, Struct, Union, Enum, Trait, TypeAlias, ImplBlo
 
 impl GenericParams {
     pub(crate) fn generic_params_query(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         def: GenericDef,
     ) -> Arc<GenericParams> {
         let mut generics = GenericParams::default();
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 06b6888f4..79e32e579 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -9,7 +9,7 @@ use ra_prof::profile;
 use mbe::MacroRules;
 
 use crate::{
-    Module, DefDatabase, AstId, FileAstId,
+    Module, DefDatabase, AstId, FileAstId, AstDatabase,
 };
 
 /// hir makes heavy use of ids: integer (u32) handlers to various things. You
@@ -37,7 +37,7 @@ pub struct HirFileId(HirFileIdRepr);
 impl HirFileId {
     /// For macro-expansion files, returns the file original source file the
     /// expansion originated from.
-    pub fn original_file(self, db: &impl DefDatabase) -> FileId {
+    pub fn original_file(self, db: &impl AstDatabase) -> FileId {
         match self.0 {
             HirFileIdRepr::File(file_id) => file_id,
             HirFileIdRepr::Macro(macro_file) => {
@@ -58,7 +58,7 @@ impl HirFileId {
     }
 
     pub(crate) fn parse_or_expand_query(
-        db: &impl DefDatabase,
+        db: &impl AstDatabase,
         file_id: HirFileId,
     ) -> Option<TreeArc<SyntaxNode>> {
         db.check_canceled();
@@ -120,7 +120,7 @@ impl From<FileId> for HirFileId {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct MacroDefId(pub(crate) AstId<ast::MacroCall>);
 
-pub(crate) fn macro_def_query(db: &impl DefDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
+pub(crate) fn macro_def_query(db: &impl AstDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
     let macro_call = id.0.to_node(db);
     let arg = macro_call.token_tree()?;
     let (tt, _) = mbe::ast_to_token_tree(arg).or_else(|| {
@@ -134,7 +134,7 @@ pub(crate) fn macro_def_query(db: &impl DefDatabase, id: MacroDefId) -> Option<A
     Some(Arc::new(rules))
 }
 
-pub(crate) fn macro_arg_query(db: &impl DefDatabase, id: MacroCallId) -> Option<Arc<tt::Subtree>> {
+pub(crate) fn macro_arg_query(db: &impl AstDatabase, id: MacroCallId) -> Option<Arc<tt::Subtree>> {
     let loc = id.loc(db);
     let macro_call = loc.ast_id.to_node(db);
     let arg = macro_call.token_tree()?;
@@ -143,7 +143,7 @@ pub(crate) fn macro_arg_query(db: &impl DefDatabase, id: MacroCallId) -> Option<
 }
 
 pub(crate) fn macro_expand_query(
-    db: &impl DefDatabase,
+    db: &impl AstDatabase,
     id: MacroCallId,
 ) -> Result<Arc<tt::Subtree>, String> {
     let loc = id.loc(db);
@@ -185,7 +185,7 @@ pub struct MacroCallLoc {
 }
 
 impl MacroCallId {
-    pub(crate) fn loc(self, db: &impl DefDatabase) -> MacroCallLoc {
+    pub(crate) fn loc(self, db: &impl AstDatabase) -> MacroCallLoc {
         db.lookup_intern_macro(self)
     }
 
@@ -196,7 +196,7 @@ impl MacroCallId {
 }
 
 impl MacroCallLoc {
-    pub(crate) fn id(self, db: &impl DefDatabase) -> MacroCallId {
+    pub(crate) fn id(self, db: &impl AstDatabase) -> MacroCallId {
         db.intern_macro(self)
     }
 }
@@ -233,7 +233,7 @@ pub(crate) struct LocationCtx<DB> {
     file_id: HirFileId,
 }
 
-impl<'a, DB: DefDatabase> LocationCtx<&'a DB> {
+impl<'a, DB: DefDatabase + AstDatabase> LocationCtx<&'a DB> {
     pub(crate) fn new(db: &'a DB, module: Module, file_id: HirFileId) -> LocationCtx<&'a DB> {
         LocationCtx { db, module, file_id }
     }
@@ -250,16 +250,19 @@ pub(crate) trait AstItemDef<N: AstNode>: salsa::InternKey + Clone {
     fn intern(db: &impl DefDatabase, loc: ItemLoc<N>) -> Self;
     fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<N>;
 
-    fn from_ast(ctx: LocationCtx<&impl DefDatabase>, ast: &N) -> Self {
+    fn from_ast(ctx: LocationCtx<&(impl AstDatabase + DefDatabase)>, ast: &N) -> Self {
         let items = ctx.db.ast_id_map(ctx.file_id);
         let item_id = items.ast_id(ast);
         Self::from_ast_id(ctx, item_id)
     }
-    fn from_ast_id(ctx: LocationCtx<&impl DefDatabase>, ast_id: FileAstId<N>) -> Self {
+    fn from_ast_id(
+        ctx: LocationCtx<&(impl AstDatabase + DefDatabase)>,
+        ast_id: FileAstId<N>,
+    ) -> Self {
         let loc = ItemLoc { module: ctx.module, ast_id: ast_id.with_file_id(ctx.file_id) };
         Self::intern(ctx.db, loc)
     }
-    fn source(self, db: &impl DefDatabase) -> (HirFileId, TreeArc<N>) {
+    fn source(self, db: &(impl AstDatabase + DefDatabase)) -> (HirFileId, TreeArc<N>) {
         let loc = self.lookup_intern(db);
         let ast = loc.ast_id.to_node(db);
         (loc.ast_id.file_id(), ast)
@@ -356,7 +359,7 @@ impl AstItemDef<ast::TypeAliasDef> for TypeAliasId {
 }
 
 impl MacroCallId {
-    pub fn debug_dump(&self, db: &impl DefDatabase) -> String {
+    pub fn debug_dump(&self, db: &impl AstDatabase) -> String {
         let loc = self.clone().loc(db);
         let node = loc.ast_id.to_node(db);
         let syntax_str = node.syntax().text().chunks().collect::<Vec<_>>().join(" ");
@@ -367,7 +370,7 @@ impl MacroCallId {
         let macro_rules = db.macro_def(loc.def);
 
         format!(
-            "macro call [file: {:#?}] : {}\nhas rules: {}",
+            "macro call [file: {:?}] : {}\nhas rules: {}",
             db.file_relative_path(original),
             syntax_str,
             macro_rules.is_some()
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index 072670444..ba90e67e9 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -8,7 +8,7 @@ use ra_syntax::{
 };
 
 use crate::{
-    Const, TypeAlias, Function, HirFileId,
+    Const, TypeAlias, Function, HirFileId, AstDatabase,
     HirDatabase, DefDatabase, TraitRef,
     type_ref::TypeRef,
     ids::LocationCtx,
@@ -58,7 +58,10 @@ impl ImplBlock {
     }
 
     /// Returns the syntax of the impl block
-    pub fn source(&self, db: &impl DefDatabase) -> (HirFileId, TreeArc<ast::ImplBlock>) {
+    pub fn source(
+        &self,
+        db: &(impl DefDatabase + AstDatabase),
+    ) -> (HirFileId, TreeArc<ast::ImplBlock>) {
         let source_map = db.impls_in_module_with_source_map(self.module).1;
         let (file_id, source) = self.module.definition_source(db);
         (file_id, source_map.get(&source, self.impl_id))
@@ -117,7 +120,7 @@ pub struct ImplData {
 
 impl ImplData {
     pub(crate) fn from_ast(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         file_id: HirFileId,
         module: Module,
         node: &ast::ImplBlock,
@@ -187,7 +190,11 @@ pub struct ModuleImplBlocks {
 }
 
 impl ModuleImplBlocks {
-    fn collect(db: &impl DefDatabase, module: Module, source_map: &mut ImplSourceMap) -> Self {
+    fn collect(
+        db: &(impl DefDatabase + AstDatabase),
+        module: Module,
+        source_map: &mut ImplSourceMap,
+    ) -> Self {
         let mut m = ModuleImplBlocks {
             module,
             impls: Arena::default(),
@@ -218,7 +225,7 @@ impl ModuleImplBlocks {
 }
 
 pub(crate) fn impls_in_module_with_source_map_query(
-    db: &impl DefDatabase,
+    db: &(impl DefDatabase + AstDatabase),
     module: Module,
 ) -> (Arc<ModuleImplBlocks>, Arc<ImplSourceMap>) {
     let mut source_map = ImplSourceMap::default();
diff --git a/crates/ra_hir/src/lang_item.rs b/crates/ra_hir/src/lang_item.rs
index 5f3f91cba..4cacaeba4 100644
--- a/crates/ra_hir/src/lang_item.rs
+++ b/crates/ra_hir/src/lang_item.rs
@@ -4,7 +4,7 @@ use rustc_hash::FxHashMap;
 use ra_syntax::{SmolStr, ast::AttrsOwner};
 
 use crate::{
-    Crate, DefDatabase, Enum, Function, HirDatabase, ImplBlock, Module, Static, Struct, Trait
+    Crate, DefDatabase, Enum, Function, HirDatabase, ImplBlock, Module, Static, Struct, Trait, AstDatabase,
 };
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -41,7 +41,10 @@ impl LangItems {
     }
 
     /// Salsa query. This will look for lang items in a specific crate.
-    pub(crate) fn lang_items_query(db: &impl DefDatabase, krate: Crate) -> Arc<LangItems> {
+    pub(crate) fn lang_items_query(
+        db: &(impl DefDatabase + AstDatabase),
+        krate: Crate,
+    ) -> Arc<LangItems> {
         let mut lang_items = LangItems { items: FxHashMap::default() };
 
         if let Some(module) = krate.root_module(db) {
@@ -74,7 +77,11 @@ impl LangItems {
         }
     }
 
-    fn collect_lang_items_recursive(&mut self, db: &impl DefDatabase, module: &Module) {
+    fn collect_lang_items_recursive(
+        &mut self,
+        db: &(impl DefDatabase + AstDatabase),
+        module: &Module,
+    ) {
         // Look for impl targets
         let (impl_blocks, source_map) = db.impls_in_module_with_source_map(module.clone());
         let source = module.definition_source(db).1;
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index 3e00eea26..f2a31795d 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -48,7 +48,7 @@ mod code_model;
 mod marks;
 
 use crate::{
-    db::{HirDatabase, DefDatabase},
+    db::{AstDatabase, DefDatabase, HirDatabase},
     name::{AsName, KnownName},
     source_id::{FileAstId, AstId},
     resolve::Resolver,
diff --git a/crates/ra_hir/src/mock.rs b/crates/ra_hir/src/mock.rs
index b84cb7503..5d38ac76c 100644
--- a/crates/ra_hir/src/mock.rs
+++ b/crates/ra_hir/src/mock.rs
@@ -13,7 +13,12 @@ use crate::{db, diagnostics::DiagnosticSink};
 
 pub const WORKSPACE: SourceRootId = SourceRootId(0);
 
-#[salsa::database(ra_db::SourceDatabaseStorage, db::HirDatabaseStorage, db::DefDatabaseStorage)]
+#[salsa::database(
+    ra_db::SourceDatabaseStorage,
+    db::AstDatabaseStorage,
+    db::DefDatabaseStorage,
+    db::HirDatabaseStorage
+)]
 #[derive(Debug)]
 pub struct MockDatabase {
     events: Mutex<Option<Vec<salsa::Event<MockDatabase>>>>,
diff --git a/crates/ra_hir/src/nameres.rs b/crates/ra_hir/src/nameres.rs
index 6b1160aa7..d649aa820 100644
--- a/crates/ra_hir/src/nameres.rs
+++ b/crates/ra_hir/src/nameres.rs
@@ -65,7 +65,7 @@ use ra_prof::profile;
 use once_cell::sync::Lazy;
 
 use crate::{
-    ModuleDef, Name, Crate, Module, MacroDef, AsName, BuiltinType,
+    ModuleDef, Name, Crate, Module, MacroDef, AsName, BuiltinType, AstDatabase,
     DefDatabase, Path, PathKind, HirFileId, Trait,
     ids::MacroDefId,
     diagnostics::DiagnosticSink,
@@ -232,7 +232,10 @@ fn or(left: ItemOrMacro, right: ItemOrMacro) -> ItemOrMacro {
 }
 
 impl CrateDefMap {
-    pub(crate) fn crate_def_map_query(db: &impl DefDatabase, krate: Crate) -> Arc<CrateDefMap> {
+    pub(crate) fn crate_def_map_query(
+        db: &(impl DefDatabase + AstDatabase),
+        krate: Crate,
+    ) -> Arc<CrateDefMap> {
         db.check_canceled();
         let _p = profile("crate_def_map_query");
         let def_map = {
@@ -278,7 +281,7 @@ impl CrateDefMap {
 
     pub(crate) fn add_diagnostics(
         &self,
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         module: CrateModuleId,
         sink: &mut DiagnosticSink,
     ) {
@@ -534,7 +537,7 @@ mod diagnostics {
     use ra_syntax::{AstPtr, ast};
 
     use crate::{
-        AstId, DefDatabase,
+        AstId, DefDatabase, AstDatabase,
         nameres::CrateModuleId,
         diagnostics::{DiagnosticSink, UnresolvedModule}
 };
@@ -551,7 +554,7 @@ mod diagnostics {
     impl DefDiagnostic {
         pub(super) fn add_to(
             &self,
-            db: &impl DefDatabase,
+            db: &(impl DefDatabase + AstDatabase),
             target_module: CrateModuleId,
             sink: &mut DiagnosticSink,
         ) {
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index af8ac064c..693c3fe8e 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -8,7 +8,7 @@ use ra_syntax::ast;
 
 use crate::{
     Function, Module, Struct, Union, Enum, Const, Static, Trait, TypeAlias, MacroDef,
-    DefDatabase, HirFileId, Name, Path,
+    DefDatabase, HirFileId, Name, Path, AstDatabase,
     KnownName,
     nameres::{
         Resolution, PerNs, ModuleDef, ReachedFixedPoint, ResolveMode,
@@ -20,7 +20,10 @@ use crate::{
     AstId,
 };
 
-pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
+pub(super) fn collect_defs(
+    db: &(impl DefDatabase + AstDatabase),
+    mut def_map: CrateDefMap,
+) -> CrateDefMap {
     // populate external prelude
     for dep in def_map.krate.dependencies(db) {
         log::debug!("crate dep {:?} -> {:?}", dep.name, dep.krate);
@@ -93,7 +96,7 @@ struct DefCollector<DB> {
 
 impl<'a, DB> DefCollector<&'a DB>
 where
-    DB: DefDatabase,
+    DB: DefDatabase + AstDatabase,
 {
     fn collect(&mut self) {
         let crate_graph = self.db.crate_graph();
@@ -470,7 +473,7 @@ struct ModCollector<'a, D> {
 
 impl<DB> ModCollector<'_, &'_ mut DefCollector<&'_ DB>>
 where
-    DB: DefDatabase,
+    DB: DefDatabase + AstDatabase,
 {
     fn collect(&mut self, items: &[raw::RawItem]) {
         for item in items {
@@ -615,7 +618,7 @@ fn is_macro_rules(path: &Path) -> bool {
 }
 
 fn resolve_submodule(
-    db: &impl DefDatabase,
+    db: &(impl DefDatabase + AstDatabase),
     file_id: HirFileId,
     name: &Name,
     is_root: bool,
@@ -658,7 +661,7 @@ mod tests {
     use rustc_hash::FxHashSet;
 
     fn do_collect_defs(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         def_map: CrateDefMap,
         monitor: MacroStackMonitor,
     ) -> CrateDefMap {
diff --git a/crates/ra_hir/src/nameres/raw.rs b/crates/ra_hir/src/nameres/raw.rs
index 1b4dcbb7a..21935dbb9 100644
--- a/crates/ra_hir/src/nameres/raw.rs
+++ b/crates/ra_hir/src/nameres/raw.rs
@@ -7,7 +7,7 @@ use ra_syntax::{
     ast::{self, NameOwner, AttrsOwner},
 };
 
-use crate::{DefDatabase, Name, AsName, Path, HirFileId, ModuleSource, AstIdMap, FileAstId, Either};
+use crate::{DefDatabase, Name, AsName, Path, HirFileId, ModuleSource, AstIdMap, FileAstId, Either, AstDatabase};
 
 /// `RawItems` is a set of top-level items in a file (except for impls).
 ///
@@ -56,12 +56,15 @@ impl ImportSourceMap {
 }
 
 impl RawItems {
-    pub(crate) fn raw_items_query(db: &impl DefDatabase, file_id: HirFileId) -> Arc<RawItems> {
+    pub(crate) fn raw_items_query(
+        db: &(impl DefDatabase + AstDatabase),
+        file_id: HirFileId,
+    ) -> Arc<RawItems> {
         db.raw_items_with_source_map(file_id).0
     }
 
     pub(crate) fn raw_items_with_source_map_query(
-        db: &impl DefDatabase,
+        db: &(impl DefDatabase + AstDatabase),
         file_id: HirFileId,
     ) -> (Arc<RawItems>, Arc<ImportSourceMap>) {
         let mut collector = RawItemsCollector {
diff --git a/crates/ra_hir/src/source_id.rs b/crates/ra_hir/src/source_id.rs
index 13f548eaf..986269e00 100644
--- a/crates/ra_hir/src/source_id.rs
+++ b/crates/ra_hir/src/source_id.rs
@@ -3,7 +3,7 @@ use std::{marker::PhantomData, sync::Arc, hash::{Hash, Hasher}};
 use ra_arena::{Arena, RawId, impl_arena_id};
 use ra_syntax::{SyntaxNodePtr, TreeArc, SyntaxNode, AstNode, ast};
 
-use crate::{HirFileId, DefDatabase};
+use crate::{HirFileId, AstDatabase};
 
 /// `AstId` points to an AST node in any file.
 ///
@@ -38,7 +38,7 @@ impl<N: AstNode> AstId<N> {
         self.file_id
     }
 
-    pub(crate) fn to_node(&self, db: &impl DefDatabase) -> TreeArc<N> {
+    pub(crate) fn to_node(&self, db: &impl AstDatabase) -> TreeArc<N> {
         let syntax_node = db.ast_id_to_node(self.file_id, self.file_ast_id.raw);
         N::cast(&syntax_node).unwrap().to_owned()
     }
@@ -87,7 +87,7 @@ pub struct AstIdMap {
 }
 
 impl AstIdMap {
-    pub(crate) fn ast_id_map_query(db: &impl DefDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
+    pub(crate) fn ast_id_map_query(db: &impl AstDatabase, file_id: HirFileId) -> Arc<AstIdMap> {
         let map = if let Some(node) = db.parse_or_expand(file_id) {
             AstIdMap::from_source(&*node)
         } else {
@@ -97,7 +97,7 @@ impl AstIdMap {
     }
 
     pub(crate) fn file_item_query(
-        db: &impl DefDatabase,
+        db: &impl AstDatabase,
         file_id: HirFileId,
         ast_id: ErasedFileAstId,
     ) -> TreeArc<SyntaxNode> {
diff --git a/crates/ra_hir/src/traits.rs b/crates/ra_hir/src/traits.rs
index dfe883fa4..2a7c2b791 100644
--- a/crates/ra_hir/src/traits.rs
+++ b/crates/ra_hir/src/traits.rs
@@ -5,7 +5,10 @@ use rustc_hash::FxHashMap;
 
 use ra_syntax::ast::{self, NameOwner};
 
-use crate::{Function, Const, TypeAlias, Name, DefDatabase, Trait, ids::LocationCtx, name::AsName, Module};
+use crate::{
+    Function, Const, TypeAlias, Name, DefDatabase, Trait, AstDatabase, Module,
+    ids::LocationCtx, name::AsName,
+};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct TraitData {
@@ -15,7 +18,10 @@ pub struct TraitData {
 }
 
 impl TraitData {
-    pub(crate) fn trait_data_query(db: &impl DefDatabase, tr: Trait) -> Arc<TraitData> {
+    pub(crate) fn trait_data_query(
+        db: &(impl DefDatabase + AstDatabase),
+        tr: Trait,
+    ) -> Arc<TraitData> {
         let (file_id, node) = tr.source(db);
         let name = node.name().map(|n| n.as_name());
         let module = tr.module(db);
diff --git a/crates/ra_hir/src/type_alias.rs b/crates/ra_hir/src/type_alias.rs
index e35adcb2f..970468e3c 100644
--- a/crates/ra_hir/src/type_alias.rs
+++ b/crates/ra_hir/src/type_alias.rs
@@ -2,9 +2,12 @@
 
 use std::sync::Arc;
 
-use crate::{TypeAlias, db::DefDatabase, type_ref::TypeRef};
+use crate::{TypeAlias, DefDatabase, AstDatabase, type_ref::TypeRef};
 
-pub(crate) fn type_alias_ref_query(db: &impl DefDatabase, typ: TypeAlias) -> Arc<TypeRef> {
+pub(crate) fn type_alias_ref_query(
+    db: &(impl DefDatabase + AstDatabase),
+    typ: TypeAlias,
+) -> Arc<TypeRef> {
     let (_, node) = typ.source(db);
     Arc::new(TypeRef::from_ast_opt(node.type_ref()))
 }