12 files changed, 87 insertions, 456 deletions

diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index f05ec0b8a..143dae6bd 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -19,12 +19,13 @@ ra_cfg = { path = "../ra_cfg" }
 ra_db = { path = "../ra_db" }
 mbe = { path = "../ra_mbe", package = "ra_mbe" }
 tt = { path = "../ra_tt", package = "ra_tt" }
+hir_expand = { path = "../ra_hir_expand", package = "ra_hir_expand" }
 test_utils = { path = "../test_utils" }
 ra_prof = { path = "../ra_prof" }
 
-chalk-solve = { git = "https://github.com/rust-lang/chalk.git", rev = "1e5c1929364dfbb7c0c7ac0956b8250abe7c2cae" }
-chalk-rust-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "1e5c1929364dfbb7c0c7ac0956b8250abe7c2cae" }
-chalk-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "1e5c1929364dfbb7c0c7ac0956b8250abe7c2cae" }
+chalk-solve = { git = "https://github.com/rust-lang/chalk.git", rev = "8314f2fcec8582a58c24b638f1a259d4145a0809" }
+chalk-rust-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "8314f2fcec8582a58c24b638f1a259d4145a0809" }
+chalk-ir = { git = "https://github.com/rust-lang/chalk.git", rev = "8314f2fcec8582a58c24b638f1a259d4145a0809" }
 lalrpop-intern = "0.15.1"
 
 [dev-dependencies]
diff --git a/crates/ra_hir/src/db.rs b/crates/ra_hir/src/db.rs
index 489a3b19c..6d34c671d 100644
--- a/crates/ra_hir/src/db.rs
+++ b/crates/ra_hir/src/db.rs
@@ -3,7 +3,7 @@
 use std::sync::Arc;
 
 use ra_db::{salsa, SourceDatabase};
-use ra_syntax::{ast, Parse, SmolStr, SyntaxNode};
+use ra_syntax::{ast, SmolStr};
 
 use crate::{
     adt::{EnumData, StructData},
@@ -19,9 +19,13 @@ use crate::{
         InferenceResult, Substs, Ty, TypableDef, TypeCtor,
     },
     type_alias::TypeAliasData,
-    AstIdMap, Const, ConstData, Crate, DefWithBody, Enum, ErasedFileAstId, ExprScopes, FnData,
-    Function, HirFileId, MacroCallLoc, MacroDefId, Module, Static, Struct, StructField, Trait,
-    TypeAlias,
+    Const, ConstData, Crate, DefWithBody, Enum, ExprScopes, FnData, Function, HirFileId, Module,
+    Static, Struct, StructField, Trait, TypeAlias,
+};
+
+pub use hir_expand::db::{
+    AstDatabase, AstDatabaseStorage, AstIdMapQuery, MacroArgQuery, MacroDefQuery, MacroExpandQuery,
+    ParseMacroQuery,
 };
 
 /// We store all interned things in the single QueryGroup.
@@ -32,8 +36,6 @@ use crate::{
 #[salsa::query_group(InternDatabaseStorage)]
 pub trait InternDatabase: SourceDatabase {
     #[salsa::interned]
-    fn intern_macro(&self, macro_call: MacroCallLoc) -> ids::MacroCallId;
-    #[salsa::interned]
     fn intern_function(&self, loc: ids::ItemLoc<ast::FnDef>) -> ids::FunctionId;
     #[salsa::interned]
     fn intern_struct(&self, loc: ids::ItemLoc<ast::StructDef>) -> ids::StructId;
@@ -55,38 +57,10 @@ pub trait InternDatabase: SourceDatabase {
     fn intern_impl(&self, impl_: Impl) -> ids::GlobalImplId;
 }
 
-/// This database has access to source code, so queries here are not really
-/// incremental.
-#[salsa::query_group(AstDatabaseStorage)]
-pub trait AstDatabase: InternDatabase {
-    #[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) -> SyntaxNode;
-
-    #[salsa::transparent]
-    #[salsa::invoke(crate::ids::HirFileId::parse_or_expand_query)]
-    fn parse_or_expand(&self, file_id: HirFileId) -> Option<SyntaxNode>;
-
-    #[salsa::invoke(crate::ids::HirFileId::parse_macro_query)]
-    fn parse_macro(&self, macro_file: ids::MacroFile) -> Option<Parse<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: InternDatabase + HirDebugDatabase {
+pub trait DefDatabase: InternDatabase + HirDebugDatabase + AstDatabase {
     #[salsa::invoke(crate::adt::StructData::struct_data_query)]
     fn struct_data(&self, s: Struct) -> Arc<StructData>;
 
diff --git a/crates/ra_hir/src/debug.rs b/crates/ra_hir/src/debug.rs
index 48b69000b..4f3e922c3 100644
--- a/crates/ra_hir/src/debug.rs
+++ b/crates/ra_hir/src/debug.rs
@@ -36,12 +36,6 @@ impl Module {
     }
 }
 
-impl HirFileId {
-    pub fn debug(self, db: &impl HirDebugDatabase) -> impl fmt::Debug + '_ {
-        debug_fn(move |fmt| db.debug_hir_file_id(self, fmt))
-    }
-}
-
 pub trait HirDebugHelper: HirDatabase {
     fn crate_name(&self, _krate: CrateId) -> Option<String> {
         None
diff --git a/crates/ra_hir/src/expr/lower.rs b/crates/ra_hir/src/expr/lower.rs
index 50ea429ea..b3a9a2e6b 100644
--- a/crates/ra_hir/src/expr/lower.rs
+++ b/crates/ra_hir/src/expr/lower.rs
@@ -16,7 +16,7 @@ use crate::{
     path::GenericArgs,
     ty::primitive::{FloatTy, IntTy, UncertainFloatTy, UncertainIntTy},
     type_ref::TypeRef,
-    DefWithBody, Either, HirFileId, MacroCallLoc, MacroFileKind, Mutability, Path, Resolver,
+    AstId, DefWithBody, Either, HirFileId, MacroCallLoc, MacroFileKind, Mutability, Path, Resolver,
     Source,
 };
 
@@ -458,15 +458,14 @@ where
             ast::Expr::Label(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::Expr::RangeExpr(_e) => self.alloc_expr(Expr::Missing, syntax_ptr),
             ast::Expr::MacroCall(e) => {
-                let ast_id = self
-                    .db
-                    .ast_id_map(self.current_file_id)
-                    .ast_id(&e)
-                    .with_file_id(self.current_file_id);
+                let ast_id = AstId::new(
+                    self.current_file_id,
+                    self.db.ast_id_map(self.current_file_id).ast_id(&e),
+                );
 
                 if let Some(path) = e.path().and_then(|path| self.parse_path(path)) {
                     if let Some(def) = self.resolver.resolve_path_as_macro(self.db, &path) {
-                        let call_id = MacroCallLoc { def: def.id, ast_id }.id(self.db);
+                        let call_id = self.db.intern_macro(MacroCallLoc { def: def.id, ast_id });
                         let file_id = call_id.as_file(MacroFileKind::Expr);
                         if let Some(node) = self.db.parse_or_expand(file_id) {
                             if let Some(expr) = ast::Expr::cast(node) {
diff --git a/crates/ra_hir/src/from_source.rs b/crates/ra_hir/src/from_source.rs
index f80d8eb5f..7954c04b2 100644
--- a/crates/ra_hir/src/from_source.rs
+++ b/crates/ra_hir/src/from_source.rs
@@ -11,7 +11,7 @@ use crate::{
     db::{AstDatabase, DefDatabase, HirDatabase},
     ids::{AstItemDef, LocationCtx},
     name::AsName,
-    Const, Crate, Enum, EnumVariant, FieldSource, Function, HasSource, ImplBlock, Module,
+    AstId, Const, Crate, Enum, EnumVariant, FieldSource, Function, HasSource, ImplBlock, Module,
     ModuleSource, Source, Static, Struct, StructField, Trait, TypeAlias, Union, VariantDef,
 };
 
@@ -183,7 +183,7 @@ impl Module {
             ModuleSource::Module(ref module) => {
                 assert!(!module.has_semi());
                 let ast_id_map = db.ast_id_map(src.file_id);
-                let item_id = ast_id_map.ast_id(module).with_file_id(src.file_id);
+                let item_id = AstId::new(src.file_id, ast_id_map.ast_id(module));
                 Some(item_id)
             }
             ModuleSource::SourceFile(_) => None,
diff --git a/crates/ra_hir/src/ids.rs b/crates/ra_hir/src/ids.rs
index 499dcafea..dea288eb7 100644
--- a/crates/ra_hir/src/ids.rs
+++ b/crates/ra_hir/src/ids.rs
@@ -1,168 +1,21 @@
-//! FIXME: write short doc here
+//! hir makes heavy use of ids: integer (u32) handlers to various things. You
+//! can think of id as a pointer (but without a lifetime) or a file descriptor
+//! (but for hir objects).
+//!
+//! This module defines a bunch of ids we are using. The most important ones are
+//! probably `HirFileId` and `DefId`.
 
-use std::{
-    hash::{Hash, Hasher},
-    sync::Arc,
-};
+use std::hash::{Hash, Hasher};
 
-use mbe::MacroRules;
-use ra_db::{salsa, FileId};
-use ra_prof::profile;
-use ra_syntax::{ast, AstNode, Parse, SyntaxNode};
+use ra_db::salsa;
+use ra_syntax::{ast, AstNode};
 
 use crate::{
-    db::{AstDatabase, DefDatabase, InternDatabase},
-    AstId, Crate, FileAstId, Module, Source,
+    db::{AstDatabase, InternDatabase},
+    AstId, FileAstId, Module, Source,
 };
 
-/// hir makes heavy use of ids: integer (u32) handlers to various things. You
-/// can think of id as a pointer (but without a lifetime) or a file descriptor
-/// (but for hir objects).
-///
-/// This module defines a bunch of ids we are using. The most important ones are
-/// probably `HirFileId` and `DefId`.
-
-/// Input to the analyzer is a set of files, where each file is identified by
-/// `FileId` and contains source code. However, another source of source code in
-/// Rust are macros: each macro can be thought of as producing a "temporary
-/// file". To assign an id to such a file, we use the id of the macro call that
-/// produced the file. So, a `HirFileId` is either a `FileId` (source code
-/// written by user), or a `MacroCallId` (source code produced by macro).
-///
-/// What is a `MacroCallId`? Simplifying, it's a `HirFileId` of a file
-/// containing the call plus the offset of the macro call in the file. Note that
-/// this is a recursive definition! However, the size_of of `HirFileId` is
-/// finite (because everything bottoms out at the real `FileId`) and small
-/// (`MacroCallId` uses the location interner).
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-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 InternDatabase) -> FileId {
-        match self.0 {
-            HirFileIdRepr::File(file_id) => file_id,
-            HirFileIdRepr::Macro(macro_file) => {
-                let loc = macro_file.macro_call_id.loc(db);
-                loc.ast_id.file_id().original_file(db)
-            }
-        }
-    }
-
-    /// Get the crate which the macro lives in, if it is a macro file.
-    pub(crate) fn macro_crate(self, db: &impl AstDatabase) -> Option<Crate> {
-        match self.0 {
-            HirFileIdRepr::File(_) => None,
-            HirFileIdRepr::Macro(macro_file) => {
-                let loc = macro_file.macro_call_id.loc(db);
-                Some(loc.def.krate)
-            }
-        }
-    }
-
-    pub(crate) fn parse_or_expand_query(
-        db: &impl AstDatabase,
-        file_id: HirFileId,
-    ) -> Option<SyntaxNode> {
-        match file_id.0 {
-            HirFileIdRepr::File(file_id) => Some(db.parse(file_id).tree().syntax().clone()),
-            HirFileIdRepr::Macro(macro_file) => {
-                db.parse_macro(macro_file).map(|it| it.syntax_node())
-            }
-        }
-    }
-
-    pub(crate) fn parse_macro_query(
-        db: &impl AstDatabase,
-        macro_file: MacroFile,
-    ) -> Option<Parse<SyntaxNode>> {
-        let _p = profile("parse_macro_query");
-        let macro_call_id = macro_file.macro_call_id;
-        let tt = db
-            .macro_expand(macro_call_id)
-            .map_err(|err| {
-                // Note:
-                // The final goal we would like to make all parse_macro success,
-                // such that the following log will not call anyway.
-                log::warn!("fail on macro_parse: (reason: {})", err,);
-            })
-            .ok()?;
-        match macro_file.macro_file_kind {
-            MacroFileKind::Items => mbe::token_tree_to_items(&tt).ok().map(Parse::to_syntax),
-            MacroFileKind::Expr => mbe::token_tree_to_expr(&tt).ok().map(Parse::to_syntax),
-        }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-enum HirFileIdRepr {
-    File(FileId),
-    Macro(MacroFile),
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct MacroFile {
-    macro_call_id: MacroCallId,
-    macro_file_kind: MacroFileKind,
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub(crate) enum MacroFileKind {
-    Items,
-    Expr,
-}
-
-impl From<FileId> for HirFileId {
-    fn from(file_id: FileId) -> HirFileId {
-        HirFileId(HirFileIdRepr::File(file_id))
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct MacroDefId {
-    pub(crate) ast_id: AstId<ast::MacroCall>,
-    pub(crate) krate: Crate,
-}
-
-pub(crate) fn macro_def_query(db: &impl AstDatabase, id: MacroDefId) -> Option<Arc<MacroRules>> {
-    let macro_call = id.ast_id.to_node(db);
-    let arg = macro_call.token_tree()?;
-    let (tt, _) = mbe::ast_to_token_tree(&arg).or_else(|| {
-        log::warn!("fail on macro_def to token tree: {:#?}", arg);
-        None
-    })?;
-    let rules = MacroRules::parse(&tt).ok().or_else(|| {
-        log::warn!("fail on macro_def parse: {:#?}", tt);
-        None
-    })?;
-    Some(Arc::new(rules))
-}
-
-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()?;
-    let (tt, _) = mbe::ast_to_token_tree(&arg)?;
-    Some(Arc::new(tt))
-}
-
-pub(crate) fn macro_expand_query(
-    db: &impl AstDatabase,
-    id: MacroCallId,
-) -> Result<Arc<tt::Subtree>, String> {
-    let loc = id.loc(db);
-    let macro_arg = db.macro_arg(id).ok_or("Fail to args in to tt::TokenTree")?;
-
-    let macro_rules = db.macro_def(loc.def).ok_or("Fail to find macro definition")?;
-    let tt = macro_rules.expand(&macro_arg).map_err(|err| format!("{:?}", err))?;
-    // Set a hard limit for the expanded tt
-    let count = tt.count();
-    if count > 65536 {
-        return Err(format!("Total tokens count exceed limit : count = {}", count));
-    }
-    Ok(Arc::new(tt))
-}
+pub use hir_expand::{HirFileId, MacroCallId, MacroCallLoc, MacroDefId, MacroFile, MacroFileKind};
 
 macro_rules! impl_intern_key {
     ($name:ident) => {
@@ -177,35 +30,6 @@ macro_rules! impl_intern_key {
     };
 }
 
-/// `MacroCallId` identifies a particular macro invocation, like
-/// `println!("Hello, {}", world)`.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct MacroCallId(salsa::InternId);
-impl_intern_key!(MacroCallId);
-
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub struct MacroCallLoc {
-    pub(crate) def: MacroDefId,
-    pub(crate) ast_id: AstId<ast::MacroCall>,
-}
-
-impl MacroCallId {
-    pub(crate) fn loc(self, db: &impl InternDatabase) -> MacroCallLoc {
-        db.lookup_intern_macro(self)
-    }
-
-    pub(crate) fn as_file(self, kind: MacroFileKind) -> HirFileId {
-        let macro_file = MacroFile { macro_call_id: self, macro_file_kind: kind };
-        HirFileId(HirFileIdRepr::Macro(macro_file))
-    }
-}
-
-impl MacroCallLoc {
-    pub(crate) fn id(self, db: &impl InternDatabase) -> MacroCallId {
-        db.intern_macro(self)
-    }
-}
-
 #[derive(Debug)]
 pub struct ItemLoc<N: AstNode> {
     pub(crate) module: Module,
@@ -238,13 +62,13 @@ pub(crate) struct LocationCtx<DB> {
     file_id: HirFileId,
 }
 
-impl<'a, DB: DefDatabase> LocationCtx<&'a DB> {
+impl<'a, DB> LocationCtx<&'a DB> {
     pub(crate) fn new(db: &'a DB, module: Module, file_id: HirFileId) -> LocationCtx<&'a DB> {
         LocationCtx { db, module, file_id }
     }
 }
 
-impl<'a, DB: DefDatabase + AstDatabase> LocationCtx<&'a DB> {
+impl<'a, DB: AstDatabase + InternDatabase> LocationCtx<&'a DB> {
     pub(crate) fn to_def<N, DEF>(self, ast: &N) -> DEF
     where
         N: AstNode,
@@ -255,24 +79,24 @@ impl<'a, DB: DefDatabase + AstDatabase> LocationCtx<&'a DB> {
 }
 
 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 intern(db: &impl InternDatabase, loc: ItemLoc<N>) -> Self;
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<N>;
 
-    fn from_ast(ctx: LocationCtx<&(impl AstDatabase + DefDatabase)>, ast: &N) -> Self {
+    fn from_ast(ctx: LocationCtx<&(impl AstDatabase + InternDatabase)>, 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 {
-        let loc = ItemLoc { module: ctx.module, ast_id: ast_id.with_file_id(ctx.file_id) };
+    fn from_ast_id(ctx: LocationCtx<&impl InternDatabase>, ast_id: FileAstId<N>) -> Self {
+        let loc = ItemLoc { module: ctx.module, ast_id: AstId::new(ctx.file_id, ast_id) };
         Self::intern(ctx.db, loc)
     }
-    fn source(self, db: &(impl AstDatabase + DefDatabase)) -> Source<N> {
+    fn source(self, db: &(impl AstDatabase + InternDatabase)) -> Source<N> {
         let loc = self.lookup_intern(db);
         let ast = loc.ast_id.to_node(db);
         Source { file_id: loc.ast_id.file_id(), ast }
     }
-    fn module(self, db: &impl DefDatabase) -> Module {
+    fn module(self, db: &impl InternDatabase) -> Module {
         let loc = self.lookup_intern(db);
         loc.module
     }
@@ -283,10 +107,10 @@ pub struct FunctionId(salsa::InternId);
 impl_intern_key!(FunctionId);
 
 impl AstItemDef<ast::FnDef> for FunctionId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::FnDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::FnDef>) -> Self {
         db.intern_function(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::FnDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::FnDef> {
         db.lookup_intern_function(self)
     }
 }
@@ -295,10 +119,10 @@ impl AstItemDef<ast::FnDef> for FunctionId {
 pub struct StructId(salsa::InternId);
 impl_intern_key!(StructId);
 impl AstItemDef<ast::StructDef> for StructId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::StructDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::StructDef>) -> Self {
         db.intern_struct(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::StructDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::StructDef> {
         db.lookup_intern_struct(self)
     }
 }
@@ -307,10 +131,10 @@ impl AstItemDef<ast::StructDef> for StructId {
 pub struct EnumId(salsa::InternId);
 impl_intern_key!(EnumId);
 impl AstItemDef<ast::EnumDef> for EnumId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::EnumDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::EnumDef>) -> Self {
         db.intern_enum(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::EnumDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::EnumDef> {
         db.lookup_intern_enum(self)
     }
 }
@@ -319,10 +143,10 @@ impl AstItemDef<ast::EnumDef> for EnumId {
 pub struct ConstId(salsa::InternId);
 impl_intern_key!(ConstId);
 impl AstItemDef<ast::ConstDef> for ConstId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::ConstDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::ConstDef>) -> Self {
         db.intern_const(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::ConstDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::ConstDef> {
         db.lookup_intern_const(self)
     }
 }
@@ -331,10 +155,10 @@ impl AstItemDef<ast::ConstDef> for ConstId {
 pub struct StaticId(salsa::InternId);
 impl_intern_key!(StaticId);
 impl AstItemDef<ast::StaticDef> for StaticId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::StaticDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::StaticDef>) -> Self {
         db.intern_static(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::StaticDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::StaticDef> {
         db.lookup_intern_static(self)
     }
 }
@@ -343,10 +167,10 @@ impl AstItemDef<ast::StaticDef> for StaticId {
 pub struct TraitId(salsa::InternId);
 impl_intern_key!(TraitId);
 impl AstItemDef<ast::TraitDef> for TraitId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::TraitDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::TraitDef>) -> Self {
         db.intern_trait(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::TraitDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::TraitDef> {
         db.lookup_intern_trait(self)
     }
 }
@@ -355,10 +179,10 @@ impl AstItemDef<ast::TraitDef> for TraitId {
 pub struct TypeAliasId(salsa::InternId);
 impl_intern_key!(TypeAliasId);
 impl AstItemDef<ast::TypeAliasDef> for TypeAliasId {
-    fn intern(db: &impl DefDatabase, loc: ItemLoc<ast::TypeAliasDef>) -> Self {
+    fn intern(db: &impl InternDatabase, loc: ItemLoc<ast::TypeAliasDef>) -> Self {
         db.intern_type_alias(loc)
     }
-    fn lookup_intern(self, db: &impl DefDatabase) -> ItemLoc<ast::TypeAliasDef> {
+    fn lookup_intern(self, db: &impl InternDatabase) -> ItemLoc<ast::TypeAliasDef> {
         db.lookup_intern_type_alias(self)
     }
 }
diff --git a/crates/ra_hir/src/impl_block.rs b/crates/ra_hir/src/impl_block.rs
index 33ef87563..1a5223680 100644
--- a/crates/ra_hir/src/impl_block.rs
+++ b/crates/ra_hir/src/impl_block.rs
@@ -20,7 +20,7 @@ use crate::{
     resolve::Resolver,
     ty::Ty,
     type_ref::TypeRef,
-    AssocItem, Const, Function, HasSource, HirFileId, MacroFileKind, Path, Source, TraitRef,
+    AssocItem, AstId, Const, Function, HasSource, HirFileId, MacroFileKind, Path, Source, TraitRef,
     TypeAlias,
 };
 
@@ -256,14 +256,14 @@ impl ModuleImplBlocks {
                     }
 
                     //FIXME: we should really cut down on the boilerplate required to process a macro
-                    let ast_id = db.ast_id_map(file_id).ast_id(&macro_call).with_file_id(file_id);
+                    let ast_id = AstId::new(file_id, db.ast_id_map(file_id).ast_id(&macro_call));
                     if let Some(path) = macro_call
                         .path()
                         .and_then(|path| Path::from_src(Source { ast: path, file_id }, db))
                     {
                         if let Some(def) = self.module.resolver(db).resolve_path_as_macro(db, &path)
                         {
-                            let call_id = MacroCallLoc { def: def.id, ast_id }.id(db);
+                            let call_id = db.intern_macro(MacroCallLoc { def: def.id, ast_id });
                             let file_id = call_id.as_file(MacroFileKind::Items);
                             if let Some(item_list) =
                                 db.parse_or_expand(file_id).and_then(ast::MacroItems::cast)
diff --git a/crates/ra_hir/src/lib.rs b/crates/ra_hir/src/lib.rs
index ca261e8f5..0f2d233bb 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -35,7 +35,6 @@ pub mod mock;
 mod path;
 pub mod source_binder;
 
-mod source_id;
 mod ids;
 mod name;
 mod nameres;
@@ -60,14 +59,14 @@ pub mod from_source;
 #[cfg(test)]
 mod marks;
 
-use crate::{
-    ids::MacroFileKind,
-    name::AsName,
-    resolve::Resolver,
-    source_id::{AstId, FileAstId},
+use hir_expand::{
+    ast_id_map::{AstIdMap, FileAstId},
+    AstId,
 };
 
-pub use self::{
+use crate::{ids::MacroFileKind, name::AsName, resolve::Resolver};
+
+pub use crate::{
     adt::VariantDef,
     either::Either,
     expr::ExprScopes,
@@ -80,7 +79,6 @@ pub use self::{
     path::{Path, PathKind},
     resolve::ScopeDef,
     source_binder::{PathResolution, ScopeEntryWithSyntax, SourceAnalyzer},
-    source_id::{AstIdMap, ErasedFileAstId},
     ty::{
         display::HirDisplay, ApplicationTy, CallableDef, Substs, TraitRef, Ty, TypeCtor, TypeWalk,
     },
diff --git a/crates/ra_hir/src/nameres/collector.rs b/crates/ra_hir/src/nameres/collector.rs
index b5fe16bfa..dc591e8d3 100644
--- a/crates/ra_hir/src/nameres/collector.rs
+++ b/crates/ra_hir/src/nameres/collector.rs
@@ -448,7 +448,7 @@ where
             );
 
             if let Some(def) = resolved_res.resolved_def.get_macros() {
-                let call_id = MacroCallLoc { def: def.id, ast_id: *ast_id }.id(self.db);
+                let call_id = self.db.intern_macro(MacroCallLoc { def: def.id, ast_id: *ast_id });
                 resolved.push((*module_id, call_id, def.id));
                 res = ReachedFixedPoint::No;
                 return false;
@@ -567,7 +567,7 @@ where
             // inline module, just recurse
             raw::ModuleData::Definition { name, items, ast_id } => {
                 let module_id =
-                    self.push_child_module(name.clone(), ast_id.with_file_id(self.file_id), None);
+                    self.push_child_module(name.clone(), AstId::new(self.file_id, *ast_id), None);
 
                 ModCollector {
                     def_collector: &mut *self.def_collector,
@@ -583,7 +583,7 @@ where
             }
             // out of line module, resolve, parse and recurse
             raw::ModuleData::Declaration { name, ast_id } => {
-                let ast_id = ast_id.with_file_id(self.file_id);
+                let ast_id = AstId::new(self.file_id, *ast_id);
                 match self.mod_dir.resolve_declaration(
                     self.def_collector.db,
                     self.file_id,
@@ -671,28 +671,26 @@ where
     }
 
     fn collect_macro(&mut self, mac: &raw::MacroData) {
+        let ast_id = AstId::new(self.file_id, mac.ast_id);
+
         // Case 1: macro rules, define a macro in crate-global mutable scope
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
-                let macro_id = MacroDefId {
-                    ast_id: mac.ast_id.with_file_id(self.file_id),
-                    krate: self.def_collector.def_map.krate,
-                };
+                let macro_id =
+                    MacroDefId { ast_id, krate: self.def_collector.def_map.krate.crate_id };
                 let macro_ = MacroDef { id: macro_id };
                 self.def_collector.define_macro(self.module_id, name.clone(), macro_, mac.export);
             }
             return;
         }
 
-        let ast_id = mac.ast_id.with_file_id(self.file_id);
-
         // Case 2: try to resolve in legacy scope and expand macro_rules, triggering
         // recursive item collection.
         if let Some(macro_def) = mac.path.as_ident().and_then(|name| {
             self.def_collector.def_map[self.module_id].scope.get_legacy_macro(&name)
         }) {
             let def = macro_def.id;
-            let macro_call_id = MacroCallLoc { def, ast_id }.id(self.def_collector.db);
+            let macro_call_id = self.def_collector.db.intern_macro(MacroCallLoc { def, ast_id });
 
             self.def_collector.collect_macro_expansion(self.module_id, macro_call_id, def);
             return;
diff --git a/crates/ra_hir/src/path.rs b/crates/ra_hir/src/path.rs
index 394617e1a..bbe536bcb 100644
--- a/crates/ra_hir/src/path.rs
+++ b/crates/ra_hir/src/path.rs
@@ -66,7 +66,12 @@ impl Path {
         mut cb: impl FnMut(Path, &ast::UseTree, bool, Option<Name>),
     ) {
         if let Some(tree) = item_src.ast.use_tree() {
-            expand_use_tree(None, tree, &|| item_src.file_id.macro_crate(db), &mut cb);
+            expand_use_tree(
+                None,
+                tree,
+                &|| item_src.file_id.macro_crate(db).map(|crate_id| Crate { crate_id }),
+                &mut cb,
+            );
         }
     }
 
@@ -90,7 +95,7 @@ impl Path {
     /// It correctly handles `$crate` based path from macro call.
     pub fn from_src(source: Source<ast::Path>, db: &impl AstDatabase) -> Option<Path> {
         let file_id = source.file_id;
-        Path::parse(source.ast, &|| file_id.macro_crate(db))
+        Path::parse(source.ast, &|| file_id.macro_crate(db).map(|crate_id| Crate { crate_id }))
     }
 
     fn parse(mut path: ast::Path, macro_crate: &impl Fn() -> Option<Crate>) -> Option<Path> {
diff --git a/crates/ra_hir/src/source_id.rs b/crates/ra_hir/src/source_id.rs
deleted file mode 100644
index a4dd99598..000000000
--- a/crates/ra_hir/src/source_id.rs
+++ /dev/null
@@ -1,161 +0,0 @@
-//! FIXME: write short doc here
-
-use std::{
-    hash::{Hash, Hasher},
-    marker::PhantomData,
-    sync::Arc,
-};
-
-use ra_arena::{impl_arena_id, Arena, RawId};
-use ra_syntax::{ast, AstNode, SyntaxNode, SyntaxNodePtr};
-
-use crate::{db::AstDatabase, HirFileId};
-
-/// `AstId` points to an AST node in any file.
-///
-/// It is stable across reparses, and can be used as salsa key/value.
-#[derive(Debug)]
-pub(crate) struct AstId<N: AstNode> {
-    file_id: HirFileId,
-    file_ast_id: FileAstId<N>,
-}
-
-impl<N: AstNode> Clone for AstId<N> {
-    fn clone(&self) -> AstId<N> {
-        *self
-    }
-}
-impl<N: AstNode> Copy for AstId<N> {}
-
-impl<N: AstNode> PartialEq for AstId<N> {
-    fn eq(&self, other: &Self) -> bool {
-        (self.file_id, self.file_ast_id) == (other.file_id, other.file_ast_id)
-    }
-}
-impl<N: AstNode> Eq for AstId<N> {}
-impl<N: AstNode> Hash for AstId<N> {
-    fn hash<H: Hasher>(&self, hasher: &mut H) {
-        (self.file_id, self.file_ast_id).hash(hasher);
-    }
-}
-
-impl<N: AstNode> AstId<N> {
-    pub(crate) fn file_id(&self) -> HirFileId {
-        self.file_id
-    }
-
-    pub(crate) fn to_node(&self, db: &impl AstDatabase) -> N {
-        let syntax_node = db.ast_id_to_node(self.file_id, self.file_ast_id.raw);
-        N::cast(syntax_node).unwrap()
-    }
-}
-
-/// `AstId` points to an AST node in a specific file.
-#[derive(Debug)]
-pub(crate) struct FileAstId<N: AstNode> {
-    raw: ErasedFileAstId,
-    _ty: PhantomData<fn() -> N>,
-}
-
-impl<N: AstNode> Clone for FileAstId<N> {
-    fn clone(&self) -> FileAstId<N> {
-        *self
-    }
-}
-impl<N: AstNode> Copy for FileAstId<N> {}
-
-impl<N: AstNode> PartialEq for FileAstId<N> {
-    fn eq(&self, other: &Self) -> bool {
-        self.raw == other.raw
-    }
-}
-impl<N: AstNode> Eq for FileAstId<N> {}
-impl<N: AstNode> Hash for FileAstId<N> {
-    fn hash<H: Hasher>(&self, hasher: &mut H) {
-        self.raw.hash(hasher);
-    }
-}
-
-impl<N: AstNode> FileAstId<N> {
-    pub(crate) fn with_file_id(self, file_id: HirFileId) -> AstId<N> {
-        AstId { file_id, file_ast_id: self }
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct ErasedFileAstId(RawId);
-impl_arena_id!(ErasedFileAstId);
-
-/// Maps items' `SyntaxNode`s to `ErasedFileAstId`s and back.
-#[derive(Debug, PartialEq, Eq, Default)]
-pub struct AstIdMap {
-    arena: Arena<ErasedFileAstId, SyntaxNodePtr>,
-}
-
-impl 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 {
-            AstIdMap::default()
-        };
-        Arc::new(map)
-    }
-
-    pub(crate) fn file_item_query(
-        db: &impl AstDatabase,
-        file_id: HirFileId,
-        ast_id: ErasedFileAstId,
-    ) -> SyntaxNode {
-        let node = db.parse_or_expand(file_id).unwrap();
-        db.ast_id_map(file_id).arena[ast_id].to_node(&node)
-    }
-
-    pub(crate) fn ast_id<N: AstNode>(&self, item: &N) -> FileAstId<N> {
-        let ptr = SyntaxNodePtr::new(item.syntax());
-        let raw = match self.arena.iter().find(|(_id, i)| **i == ptr) {
-            Some((it, _)) => it,
-            None => panic!(
-                "Can't find {:?} in AstIdMap:\n{:?}",
-                item.syntax(),
-                self.arena.iter().map(|(_id, i)| i).collect::<Vec<_>>(),
-            ),
-        };
-
-        FileAstId { raw, _ty: PhantomData }
-    }
-
-    fn from_source(node: &SyntaxNode) -> AstIdMap {
-        assert!(node.parent().is_none());
-        let mut res = AstIdMap { arena: Arena::default() };
-        // By walking the tree in bread-first order we make sure that parents
-        // get lower ids then children. That is, adding a new child does not
-        // change parent's id. This means that, say, adding a new function to a
-        // trait does not change ids of top-level items, which helps caching.
-        bfs(node, |it| {
-            if let Some(module_item) = ast::ModuleItem::cast(it.clone()) {
-                res.alloc(module_item.syntax());
-            } else if let Some(macro_call) = ast::MacroCall::cast(it) {
-                res.alloc(macro_call.syntax());
-            }
-        });
-        res
-    }
-
-    fn alloc(&mut self, item: &SyntaxNode) -> ErasedFileAstId {
-        self.arena.alloc(SyntaxNodePtr::new(item))
-    }
-}
-
-/// Walks the subtree in bfs order, calling `f` for each node.
-fn bfs(node: &SyntaxNode, mut f: impl FnMut(SyntaxNode)) {
-    let mut curr_layer = vec![node.clone()];
-    let mut next_layer = vec![];
-    while !curr_layer.is_empty() {
-        curr_layer.drain(..).for_each(|node| {
-            next_layer.extend(node.children());
-            f(node);
-        });
-        std::mem::swap(&mut curr_layer, &mut next_layer);
-    }
-}
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index ad7c11a5a..e18c28cf6 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -66,13 +66,11 @@ impl ToChalk for Ty {
             }
             Ty::Bound(idx) => chalk_ir::Ty::BoundVar(idx as usize),
             Ty::Infer(_infer_ty) => panic!("uncanonicalized infer ty"),
-            // FIXME this is clearly incorrect, but probably not too incorrect
-            // and I'm not sure what to actually do with Ty::Unknown
-            // maybe an alternative would be `for<T> T`? (meaningless in rust, but expressible in chalk's Ty)
             // FIXME use Chalk's Dyn/Opaque once the bugs with that are fixed
             Ty::Unknown | Ty::Dyn(_) | Ty::Opaque(_) => {
-                PlaceholderIndex { ui: UniverseIndex::ROOT, idx: usize::max_value() }
-                    .to_ty::<ChalkIr>()
+                let parameters = Vec::new();
+                let name = TypeName::Error;
+                chalk_ir::ApplicationTy { name, parameters }.cast()
             }
         }
     }
@@ -92,6 +90,7 @@ impl ToChalk for Ty {
                         let parameters = from_chalk(db, apply_ty.parameters);
                         Ty::Apply(ApplicationTy { ctor, parameters })
                     }
+                    TypeName::Error => Ty::Unknown,
                     // FIXME handle TypeKindId::Trait/Type here
                     TypeName::TypeKindId(_) => unimplemented!(),
                     TypeName::Placeholder(idx) => {
@@ -323,9 +322,9 @@ where
 }
 
 impl ToChalk for Arc<super::TraitEnvironment> {
-    type Chalk = Arc<chalk_ir::Environment<ChalkIr>>;
+    type Chalk = chalk_ir::Environment<ChalkIr>;
 
-    fn to_chalk(self, db: &impl HirDatabase) -> Arc<chalk_ir::Environment<ChalkIr>> {
+    fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Environment<ChalkIr> {
         let mut clauses = Vec::new();
         for pred in &self.predicates {
             if pred.is_error() {
@@ -340,7 +339,7 @@ impl ToChalk for Arc<super::TraitEnvironment> {
 
     fn from_chalk(
         _db: &impl HirDatabase,
-        _env: Arc<chalk_ir::Environment<ChalkIr>>,
+        _env: chalk_ir::Environment<ChalkIr>,
     ) -> Arc<super::TraitEnvironment> {
         unimplemented!()
     }