15 files changed, 273 insertions, 280 deletions

diff --git a/crates/ra_hir_expand/src/db.rs b/crates/ra_hir_expand/src/db.rs
index 9de7c1ea8..3c11c8a22 100644
--- a/crates/ra_hir_expand/src/db.rs
+++ b/crates/ra_hir_expand/src/db.rs
@@ -59,10 +59,8 @@ pub trait AstDatabase: SourceDatabase {
     fn intern_macro(&self, macro_call: MacroCallLoc) -> MacroCallId;
     fn macro_arg(&self, id: MacroCallId) -> Option<Arc<(tt::Subtree, mbe::TokenMap)>>;
     fn macro_def(&self, id: MacroDefId) -> Option<Arc<(TokenExpander, mbe::TokenMap)>>;
-    fn parse_macro(
-        &self,
-        macro_file: MacroFile,
-    ) -> Option<(Parse<SyntaxNode>, Arc<mbe::RevTokenMap>)>;
+    fn parse_macro(&self, macro_file: MacroFile)
+        -> Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)>;
     fn macro_expand(&self, macro_call: MacroCallId) -> Result<Arc<tt::Subtree>, String>;
 }
 
@@ -136,7 +134,7 @@ pub(crate) fn parse_or_expand(db: &dyn AstDatabase, file_id: HirFileId) -> Optio
 pub(crate) fn parse_macro(
     db: &dyn AstDatabase,
     macro_file: MacroFile,
-) -> Option<(Parse<SyntaxNode>, Arc<mbe::RevTokenMap>)> {
+) -> Option<(Parse<SyntaxNode>, Arc<mbe::TokenMap>)> {
     let _p = profile("parse_macro_query");
 
     let macro_call_id = macro_file.macro_call_id;
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 57e2e6cb1..cfe7e6d15 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -20,7 +20,7 @@ use ra_db::{salsa, CrateId, FileId};
 use ra_syntax::{
     algo,
     ast::{self, AstNode},
-    SyntaxNode, SyntaxToken, TextRange, TextUnit,
+    SyntaxNode, SyntaxToken, TextUnit,
 };
 
 use crate::ast_id_map::FileAstId;
@@ -79,22 +79,17 @@ impl HirFileId {
             HirFileIdRepr::MacroFile(macro_file) => {
                 let loc: MacroCallLoc = db.lookup_intern_macro(macro_file.macro_call_id);
 
-                let arg_start = loc.ast_id.to_node(db).token_tree()?.syntax().text_range().start();
-                let def_start =
-                    loc.def.ast_id.to_node(db).token_tree()?.syntax().text_range().start();
+                let arg_tt = loc.ast_id.to_node(db).token_tree()?;
+                let def_tt = loc.def.ast_id.to_node(db).token_tree()?;
 
                 let macro_def = db.macro_def(loc.def)?;
                 let (parse, exp_map) = db.parse_macro(macro_file)?;
-                let expanded = Source::new(self, parse.syntax_node());
                 let macro_arg = db.macro_arg(macro_file.macro_call_id)?;
 
-                let arg_start = (loc.ast_id.file_id, arg_start);
-                let def_start = (loc.def.ast_id.file_id, def_start);
-
                 Some(ExpansionInfo {
-                    expanded,
-                    arg_start,
-                    def_start,
+                    expanded: Source::new(self, parse.syntax_node()),
+                    arg: Source::new(loc.ast_id.file_id, arg_tt),
+                    def: Source::new(loc.ast_id.file_id, def_tt),
                     macro_arg,
                     macro_def,
                     exp_map,
@@ -159,18 +154,19 @@ impl MacroCallId {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ExpansionInfo {
     expanded: Source<SyntaxNode>,
-    arg_start: (HirFileId, TextUnit),
-    def_start: (HirFileId, TextUnit),
+    arg: Source<ast::TokenTree>,
+    def: Source<ast::TokenTree>,
 
     macro_def: Arc<(db::TokenExpander, mbe::TokenMap)>,
     macro_arg: Arc<(tt::Subtree, mbe::TokenMap)>,
-    exp_map: Arc<mbe::RevTokenMap>,
+    exp_map: Arc<mbe::TokenMap>,
 }
 
 impl ExpansionInfo {
     pub fn map_token_down(&self, token: Source<&SyntaxToken>) -> Option<Source<SyntaxToken>> {
-        assert_eq!(token.file_id, self.arg_start.0);
-        let range = token.ast.text_range().checked_sub(self.arg_start.1)?;
+        assert_eq!(token.file_id, self.arg.file_id);
+        let range =
+            token.ast.text_range().checked_sub(self.arg.ast.syntax().text_range().start())?;
         let token_id = self.macro_arg.1.token_by_range(range)?;
         let token_id = self.macro_def.0.map_id_down(token_id);
 
@@ -181,25 +177,22 @@ impl ExpansionInfo {
         Some(self.expanded.with_ast(token))
     }
 
-    // FIXME: a more correct signature would be
-    // `pub fn map_token_up(&self, token: Source<&SyntaxToken>) -> Option<Source<SyntaxToken>>`
-    pub fn find_range(&self, from: TextRange) -> Option<(HirFileId, TextRange)> {
-        let token_id = look_in_rev_map(&self.exp_map, from)?;
+    pub fn map_token_up(&self, token: Source<&SyntaxToken>) -> Option<Source<SyntaxToken>> {
+        let token_id = self.exp_map.token_by_range(token.ast.text_range())?;
 
         let (token_id, origin) = self.macro_def.0.map_id_up(token_id);
-
-        let (token_map, (file_id, start_offset)) = match origin {
-            mbe::Origin::Call => (&self.macro_arg.1, self.arg_start),
-            mbe::Origin::Def => (&self.macro_def.1, self.def_start),
+        let (token_map, tt) = match origin {
+            mbe::Origin::Call => (&self.macro_arg.1, &self.arg),
+            mbe::Origin::Def => (&self.macro_def.1, &self.def),
         };
 
-        let range = token_map.relative_range_of(token_id)?;
-
-        return Some((file_id, range + start_offset));
-
-        fn look_in_rev_map(exp_map: &mbe::RevTokenMap, from: TextRange) -> Option<tt::TokenId> {
-            exp_map.ranges.iter().find(|&it| it.0.is_subrange(&from)).map(|it| it.1)
-        }
+        let range = token_map.range_by_token(token_id)?;
+        let token = algo::find_covering_element(
+            tt.ast.syntax(),
+            range + tt.ast.syntax().text_range().start(),
+        )
+        .into_token()?;
+        Some(tt.with_ast(token))
     }
 }
 
diff --git a/crates/ra_ide_api/src/display/navigation_target.rs b/crates/ra_ide_api/src/display/navigation_target.rs
index f7ad08515..b30ef8e05 100644
--- a/crates/ra_ide_api/src/display/navigation_target.rs
+++ b/crates/ra_ide_api/src/display/navigation_target.rs
@@ -1,16 +1,17 @@
 //! FIXME: write short doc here
 
-use hir::{AssocItem, Either, FieldSource, HasSource, ModuleSource};
+use hir::{AssocItem, Either, FieldSource, HasSource, ModuleSource, Source};
 use ra_db::{FileId, SourceDatabase};
 use ra_syntax::{
     ast::{self, DocCommentsOwner, NameOwner},
     match_ast, AstNode, SmolStr,
     SyntaxKind::{self, BIND_PAT},
-    SyntaxNode, TextRange,
+    TextRange,
 };
 
+use crate::{db::RootDatabase, expand::original_range, FileSymbol};
+
 use super::short_label::ShortLabel;
-use crate::{db::RootDatabase, FileSymbol};
 
 /// `NavigationTarget` represents and element in the editor's UI which you can
 /// click on to navigate to a particular piece of code.
@@ -79,13 +80,13 @@ impl NavigationTarget {
     pub(crate) fn from_module_to_decl(db: &RootDatabase, module: hir::Module) -> NavigationTarget {
         let name = module.name(db).map(|it| it.to_string().into()).unwrap_or_default();
         if let Some(src) = module.declaration_source(db) {
-            let (file_id, text_range) = find_range_from_node(db, src.file_id, src.ast.syntax());
+            let frange = original_range(db, src.as_ref().map(|it| it.syntax()));
             return NavigationTarget::from_syntax(
-                file_id,
+                frange.file_id,
                 name,
                 None,
-                text_range,
-                src.ast.syntax(),
+                frange.range,
+                src.ast.syntax().kind(),
                 src.ast.doc_comment_text(),
                 src.ast.short_label(),
             );
@@ -140,22 +141,22 @@ impl NavigationTarget {
     /// Allows `NavigationTarget` to be created from a `NameOwner`
     pub(crate) fn from_named(
         db: &RootDatabase,
-        file_id: hir::HirFileId,
-        node: &impl ast::NameOwner,
+        node: Source<&dyn ast::NameOwner>,
         docs: Option<String>,
         description: Option<String>,
     ) -> NavigationTarget {
         //FIXME: use `_` instead of empty string
-        let name = node.name().map(|it| it.text().clone()).unwrap_or_default();
-        let focus_range = node.name().map(|it| find_range_from_node(db, file_id, it.syntax()).1);
-        let (file_id, full_range) = find_range_from_node(db, file_id, node.syntax());
+        let name = node.ast.name().map(|it| it.text().clone()).unwrap_or_default();
+        let focus_range =
+            node.ast.name().map(|it| original_range(db, node.with_ast(it.syntax())).range);
+        let frange = original_range(db, node.map(|it| it.syntax()));
 
         NavigationTarget::from_syntax(
-            file_id,
+            frange.file_id,
             name,
             focus_range,
-            full_range,
-            node.syntax(),
+            frange.range,
+            node.ast.syntax().kind(),
             docs,
             description,
         )
@@ -166,14 +167,14 @@ impl NavigationTarget {
         name: SmolStr,
         focus_range: Option<TextRange>,
         full_range: TextRange,
-        node: &SyntaxNode,
+        kind: SyntaxKind,
         docs: Option<String>,
         description: Option<String>,
     ) -> NavigationTarget {
         NavigationTarget {
             file_id,
             name,
-            kind: node.kind(),
+            kind,
             full_range,
             focus_range,
             container_name: None,
@@ -218,8 +219,7 @@ where
         let src = self.source(db);
         NavigationTarget::from_named(
             db,
-            src.file_id,
-            &src.ast,
+            src.as_ref().map(|it| it as &dyn ast::NameOwner),
             src.ast.doc_comment_text(),
             src.ast.short_label(),
         )
@@ -230,29 +230,29 @@ impl ToNav for hir::Module {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.definition_source(db);
         let name = self.name(db).map(|it| it.to_string().into()).unwrap_or_default();
-        match src.ast {
+        match &src.ast {
             ModuleSource::SourceFile(node) => {
-                let (file_id, text_range) = find_range_from_node(db, src.file_id, node.syntax());
+                let frange = original_range(db, src.with_ast(node.syntax()));
 
                 NavigationTarget::from_syntax(
-                    file_id,
+                    frange.file_id,
                     name,
                     None,
-                    text_range,
-                    node.syntax(),
+                    frange.range,
+                    node.syntax().kind(),
                     None,
                     None,
                 )
             }
             ModuleSource::Module(node) => {
-                let (file_id, text_range) = find_range_from_node(db, src.file_id, node.syntax());
+                let frange = original_range(db, src.with_ast(node.syntax()));
 
                 NavigationTarget::from_syntax(
-                    file_id,
+                    frange.file_id,
                     name,
                     None,
-                    text_range,
-                    node.syntax(),
+                    frange.range,
+                    node.syntax().kind(),
                     node.doc_comment_text(),
                     node.short_label(),
                 )
@@ -264,14 +264,14 @@ impl ToNav for hir::Module {
 impl ToNav for hir::ImplBlock {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.source(db);
-        let (file_id, text_range) = find_range_from_node(db, src.file_id, src.ast.syntax());
+        let frange = original_range(db, src.as_ref().map(|it| it.syntax()));
 
         NavigationTarget::from_syntax(
-            file_id,
+            frange.file_id,
             "impl".into(),
             None,
-            text_range,
-            src.ast.syntax(),
+            frange.range,
+            src.ast.syntax().kind(),
             None,
             None,
         )
@@ -282,22 +282,21 @@ impl ToNav for hir::StructField {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.source(db);
 
-        match src.ast {
+        match &src.ast {
             FieldSource::Named(it) => NavigationTarget::from_named(
                 db,
-                src.file_id,
-                &it,
+                src.with_ast(it),
                 it.doc_comment_text(),
                 it.short_label(),
             ),
             FieldSource::Pos(it) => {
-                let (file_id, text_range) = find_range_from_node(db, src.file_id, it.syntax());
+                let frange = original_range(db, src.with_ast(it.syntax()));
                 NavigationTarget::from_syntax(
-                    file_id,
+                    frange.file_id,
                     "".into(),
                     None,
-                    text_range,
-                    it.syntax(),
+                    frange.range,
+                    it.syntax().kind(),
                     None,
                     None,
                 )
@@ -310,7 +309,12 @@ impl ToNav for hir::MacroDef {
     fn to_nav(&self, db: &RootDatabase) -> NavigationTarget {
         let src = self.source(db);
         log::debug!("nav target {:#?}", src.ast.syntax());
-        NavigationTarget::from_named(db, src.file_id, &src.ast, src.ast.doc_comment_text(), None)
+        NavigationTarget::from_named(
+            db,
+            src.as_ref().map(|it| it as &dyn ast::NameOwner),
+            src.ast.doc_comment_text(),
+            None,
+        )
     }
 }
 
@@ -360,21 +364,6 @@ impl ToNav for hir::Local {
     }
 }
 
-fn find_range_from_node(
-    db: &RootDatabase,
-    src: hir::HirFileId,
-    node: &SyntaxNode,
-) -> (FileId, TextRange) {
-    let text_range = node.text_range();
-    let (file_id, text_range) = src
-        .expansion_info(db)
-        .and_then(|expansion_info| expansion_info.find_range(text_range))
-        .unwrap_or((src, text_range));
-
-    // FIXME: handle recursive macro generated macro
-    (file_id.original_file(db), text_range)
-}
-
 pub(crate) fn docs_from_symbol(db: &RootDatabase, symbol: &FileSymbol) -> Option<String> {
     let parse = db.parse(symbol.file_id);
     let node = symbol.ptr.to_node(parse.tree().syntax());
diff --git a/crates/ra_ide_api/src/expand.rs b/crates/ra_ide_api/src/expand.rs
new file mode 100644
index 000000000..7f59e46d2
--- /dev/null
+++ b/crates/ra_ide_api/src/expand.rs
@@ -0,0 +1,59 @@
+//! Utilities to work with files, produced by macros.
+use std::iter::successors;
+
+use hir::Source;
+use ra_db::FileId;
+use ra_syntax::{ast, AstNode, SyntaxNode, SyntaxToken};
+
+use crate::{db::RootDatabase, FileRange};
+
+pub(crate) fn original_range(db: &RootDatabase, node: Source<&SyntaxNode>) -> FileRange {
+    let expansion = match node.file_id.expansion_info(db) {
+        None => {
+            return FileRange {
+                file_id: node.file_id.original_file(db),
+                range: node.ast.text_range(),
+            }
+        }
+        Some(it) => it,
+    };
+    // FIXME: the following completely wrong.
+    //
+    // *First*, we should try to map first and last tokens of node, and, if that
+    // fails, return the range of the overall macro expansions.
+    //
+    // *Second*, we should handle recurside macro expansions
+
+    let token = node
+        .ast
+        .descendants_with_tokens()
+        .filter_map(|it| it.into_token())
+        .find_map(|it| expansion.map_token_up(node.with_ast(&it)));
+
+    match token {
+        Some(it) => FileRange { file_id: it.file_id.original_file(db), range: it.ast.text_range() },
+        None => FileRange { file_id: node.file_id.original_file(db), range: node.ast.text_range() },
+    }
+}
+
+pub(crate) fn descend_into_macros(
+    db: &RootDatabase,
+    file_id: FileId,
+    token: SyntaxToken,
+) -> Source<SyntaxToken> {
+    let src = Source::new(file_id.into(), token);
+
+    successors(Some(src), |token| {
+        let macro_call = token.ast.ancestors().find_map(ast::MacroCall::cast)?;
+        let tt = macro_call.token_tree()?;
+        if !token.ast.text_range().is_subrange(&tt.syntax().text_range()) {
+            return None;
+        }
+        let source_analyzer =
+            hir::SourceAnalyzer::new(db, token.with_ast(token.ast.parent()).as_ref(), None);
+        let exp = source_analyzer.expand(db, &macro_call)?;
+        exp.map_token_down(db, token.as_ref())
+    })
+    .last()
+    .unwrap()
+}
diff --git a/crates/ra_ide_api/src/goto_definition.rs b/crates/ra_ide_api/src/goto_definition.rs
index b693a4c31..3f16e9566 100644
--- a/crates/ra_ide_api/src/goto_definition.rs
+++ b/crates/ra_ide_api/src/goto_definition.rs
@@ -1,16 +1,15 @@
 //! FIXME: write short doc here
 
-use std::iter::successors;
-
 use hir::{db::AstDatabase, Source};
 use ra_syntax::{
     ast::{self, DocCommentsOwner},
-    match_ast, AstNode, SyntaxNode, SyntaxToken,
+    match_ast, AstNode, SyntaxNode,
 };
 
 use crate::{
     db::RootDatabase,
     display::{ShortLabel, ToNav},
+    expand::descend_into_macros,
     references::{classify_name_ref, NameKind::*},
     FilePosition, NavigationTarget, RangeInfo,
 };
@@ -19,7 +18,9 @@ pub(crate) fn goto_definition(
     db: &RootDatabase,
     position: FilePosition,
 ) -> Option<RangeInfo<Vec<NavigationTarget>>> {
-    let token = descend_into_macros(db, position)?;
+    let file = db.parse_or_expand(position.file_id.into())?;
+    let token = file.token_at_offset(position.offset).filter(|it| !it.kind().is_trivia()).next()?;
+    let token = descend_into_macros(db, position.file_id, token);
 
     let res = match_ast! {
         match (token.ast.parent()) {
@@ -39,24 +40,6 @@ pub(crate) fn goto_definition(
     Some(res)
 }
 
-fn descend_into_macros(db: &RootDatabase, position: FilePosition) -> Option<Source<SyntaxToken>> {
-    let file = db.parse_or_expand(position.file_id.into())?;
-    let token = file.token_at_offset(position.offset).filter(|it| !it.kind().is_trivia()).next()?;
-
-    successors(Some(Source::new(position.file_id.into(), token)), |token| {
-        let macro_call = token.ast.ancestors().find_map(ast::MacroCall::cast)?;
-        let tt = macro_call.token_tree()?;
-        if !token.ast.text_range().is_subrange(&tt.syntax().text_range()) {
-            return None;
-        }
-        let source_analyzer =
-            hir::SourceAnalyzer::new(db, token.with_ast(token.ast.parent()).as_ref(), None);
-        let exp = source_analyzer.expand(db, &macro_call)?;
-        exp.map_token_down(db, token.as_ref())
-    })
-    .last()
-}
-
 #[derive(Debug)]
 pub(crate) enum ReferenceResult {
     Exact(NavigationTarget),
@@ -137,8 +120,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::StructDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -146,8 +128,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::EnumDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -155,8 +136,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::EnumVariant(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -164,8 +144,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::FnDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -173,8 +152,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::TypeAliasDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -182,8 +160,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::ConstDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -191,8 +168,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::StaticDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -200,8 +176,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::TraitDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -209,8 +184,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::RecordFieldDef(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -218,8 +192,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::Module(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     it.short_label(),
                 ))
@@ -227,8 +200,7 @@ fn named_target(db: &RootDatabase, node: Source<&SyntaxNode>) -> Option<Navigati
             ast::MacroCall(it) => {
                 Some(NavigationTarget::from_named(
                     db,
-                    node.file_id,
-                    &it,
+                    node.with_ast(&it),
                     it.doc_comment_text(),
                     None,
                 ))
diff --git a/crates/ra_ide_api/src/hover.rs b/crates/ra_ide_api/src/hover.rs
index cc25f4c37..c6d678c0c 100644
--- a/crates/ra_ide_api/src/hover.rs
+++ b/crates/ra_ide_api/src/hover.rs
@@ -193,7 +193,9 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
             None
         }
     } else if let Some(name) = find_node_at_offset::<ast::Name>(file.syntax(), position.offset) {
-        if let Some(name_kind) = classify_name(db, position.file_id, &name).map(|d| d.kind) {
+        if let Some(name_kind) =
+            classify_name(db, Source::new(position.file_id.into(), &name)).map(|d| d.kind)
+        {
             let mut _b: bool = true;
             res.extend(hover_text_from_name_kind(db, name_kind, &mut _b));
         }
diff --git a/crates/ra_ide_api/src/lib.rs b/crates/ra_ide_api/src/lib.rs
index 484fbcc82..110ddcd62 100644
--- a/crates/ra_ide_api/src/lib.rs
+++ b/crates/ra_ide_api/src/lib.rs
@@ -41,6 +41,7 @@ mod matching_brace;
 mod display;
 mod inlay_hints;
 mod wasm_shims;
+mod expand;
 
 #[cfg(test)]
 mod marks;
diff --git a/crates/ra_ide_api/src/references.rs b/crates/ra_ide_api/src/references.rs
index 1af7e8a9f..cb343e59a 100644
--- a/crates/ra_ide_api/src/references.rs
+++ b/crates/ra_ide_api/src/references.rs
@@ -110,7 +110,7 @@ fn find_name<'a>(
     position: FilePosition,
 ) -> Option<RangeInfo<(String, NameDefinition)>> {
     if let Some(name) = find_node_at_offset::<ast::Name>(&syntax, position.offset) {
-        let def = classify_name(db, position.file_id, &name)?;
+        let def = classify_name(db, Source::new(position.file_id.into(), &name))?;
         let range = name.syntax().text_range();
         return Some(RangeInfo::new(range, (name.text().to_string(), def)));
     }
diff --git a/crates/ra_ide_api/src/references/classify.rs b/crates/ra_ide_api/src/references/classify.rs
index 5ca9da15e..ea9d20e71 100644
--- a/crates/ra_ide_api/src/references/classify.rs
+++ b/crates/ra_ide_api/src/references/classify.rs
@@ -1,7 +1,6 @@
 //! Functions that are used to classify an element from its definition or reference.
 
 use hir::{FromSource, Module, ModuleSource, Path, PathResolution, Source, SourceAnalyzer};
-use ra_db::FileId;
 use ra_prof::profile;
 use ra_syntax::{ast, match_ast, AstNode};
 use test_utils::tested_by;
@@ -12,19 +11,14 @@ use super::{
 };
 use crate::db::RootDatabase;
 
-pub(crate) fn classify_name(
-    db: &RootDatabase,
-    file_id: FileId,
-    name: &ast::Name,
-) -> Option<NameDefinition> {
+pub(crate) fn classify_name(db: &RootDatabase, name: Source<&ast::Name>) -> Option<NameDefinition> {
     let _p = profile("classify_name");
-    let parent = name.syntax().parent()?;
-    let file_id = file_id.into();
+    let parent = name.ast.syntax().parent()?;
 
     match_ast! {
         match parent {
             ast::BindPat(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let local = hir::Local::from_source(db, src)?;
                 Some(NameDefinition {
                     visibility: None,
@@ -34,7 +28,7 @@ pub(crate) fn classify_name(
             },
             ast::RecordFieldDef(it) => {
                 let ast = hir::FieldSource::Named(it);
-                let src = hir::Source { file_id, ast };
+                let src = name.with_ast(ast);
                 let field = hir::StructField::from_source(db, src)?;
                 Some(from_struct_field(db, field))
             },
@@ -42,42 +36,42 @@ pub(crate) fn classify_name(
                 let def = {
                     if !it.has_semi() {
                         let ast = hir::ModuleSource::Module(it);
-                        let src = hir::Source { file_id, ast };
+                        let src = name.with_ast(ast);
                         hir::Module::from_definition(db, src)
                     } else {
-                        let src = hir::Source { file_id, ast: it };
+                        let src = name.with_ast(it);
                         hir::Module::from_declaration(db, src)
                     }
                 }?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::StructDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Struct::from_source(db, src)?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::EnumDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Enum::from_source(db, src)?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::TraitDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Trait::from_source(db, src)?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::StaticDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Static::from_source(db, src)?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::EnumVariant(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::EnumVariant::from_source(db, src)?;
                 Some(from_module_def(db, def.into(), None))
             },
             ast::FnDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Function::from_source(db, src)?;
                 if parent.parent().and_then(ast::ItemList::cast).is_some() {
                     Some(from_assoc_item(db, def.into()))
@@ -86,7 +80,7 @@ pub(crate) fn classify_name(
                 }
             },
             ast::ConstDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::Const::from_source(db, src)?;
                 if parent.parent().and_then(ast::ItemList::cast).is_some() {
                     Some(from_assoc_item(db, def.into()))
@@ -95,7 +89,7 @@ pub(crate) fn classify_name(
                 }
             },
             ast::TypeAliasDef(it) => {
-                let src = hir::Source { file_id, ast: it };
+                let src = name.with_ast(it);
                 let def = hir::TypeAlias::from_source(db, src)?;
                 if parent.parent().and_then(ast::ItemList::cast).is_some() {
                     Some(from_assoc_item(db, def.into()))
@@ -104,11 +98,11 @@ pub(crate) fn classify_name(
                 }
             },
             ast::MacroCall(it) => {
-                let src = hir::Source { file_id, ast: it};
+                let src = name.with_ast(it);
                 let def = hir::MacroDef::from_source(db, src.clone())?;
 
                 let module_src = ModuleSource::from_child_node(db, src.as_ref().map(|it| it.syntax()));
-                let module = Module::from_definition(db, Source::new(file_id, module_src))?;
+                let module = Module::from_definition(db, src.with_ast(module_src))?;
 
                 Some(NameDefinition {
                     visibility: None,
diff --git a/crates/ra_ide_api/src/syntax_highlighting.rs b/crates/ra_ide_api/src/syntax_highlighting.rs
index 584657ca2..2b653fe8f 100644
--- a/crates/ra_ide_api/src/syntax_highlighting.rs
+++ b/crates/ra_ide_api/src/syntax_highlighting.rs
@@ -94,7 +94,8 @@ pub(crate) fn highlight(db: &RootDatabase, file_id: FileId) -> Vec<HighlightedRa
             }
             NAME => {
                 let name = node.as_node().cloned().and_then(ast::Name::cast).unwrap();
-                let name_kind = classify_name(db, file_id, &name).map(|d| d.kind);
+                let name_kind =
+                    classify_name(db, Source::new(file_id.into(), &name)).map(|d| d.kind);
 
                 if let Some(Local(local)) = &name_kind {
                     if let Some(name) = local.name(db) {
diff --git a/crates/ra_mbe/src/lib.rs b/crates/ra_mbe/src/lib.rs
index 58ca95368..bbddebe67 100644
--- a/crates/ra_mbe/src/lib.rs
+++ b/crates/ra_mbe/src/lib.rs
@@ -31,7 +31,7 @@ pub enum ExpandError {
 }
 
 pub use crate::syntax_bridge::{
-    ast_to_token_tree, syntax_node_to_token_tree, token_tree_to_syntax_node, RevTokenMap, TokenMap,
+    ast_to_token_tree, syntax_node_to_token_tree, token_tree_to_syntax_node, TokenMap,
 };
 
 /// This struct contains AST for a single `macro_rules` definition. What might
diff --git a/crates/ra_mbe/src/syntax_bridge.rs b/crates/ra_mbe/src/syntax_bridge.rs
index 8398c9ac7..d1c49c0b3 100644
--- a/crates/ra_mbe/src/syntax_bridge.rs
+++ b/crates/ra_mbe/src/syntax_bridge.rs
@@ -14,30 +14,22 @@ use crate::ExpandError;
 #[derive(Debug, PartialEq, Eq, Default)]
 pub struct TokenMap {
     /// Maps `tt::TokenId` to the *relative* source range.
-    tokens: Vec<TextRange>,
-}
-
-/// Maps relative range of the expanded syntax node to `tt::TokenId`
-#[derive(Debug, PartialEq, Eq, Default)]
-pub struct RevTokenMap {
-    pub ranges: Vec<(TextRange, tt::TokenId)>,
+    entries: Vec<(tt::TokenId, TextRange)>,
 }
 
 /// Convert the syntax tree (what user has written) to a `TokenTree` (what macro
 /// will consume).
 pub fn ast_to_token_tree(ast: &ast::TokenTree) -> Option<(tt::Subtree, TokenMap)> {
-    let mut token_map = TokenMap::default();
-    let node = ast.syntax();
-    let tt = convert_tt(&mut token_map, node.text_range().start(), node)?;
-    Some((tt, token_map))
+    syntax_node_to_token_tree(ast.syntax())
 }
 
 /// Convert the syntax node to a `TokenTree` (what macro
 /// will consume).
 pub fn syntax_node_to_token_tree(node: &SyntaxNode) -> Option<(tt::Subtree, TokenMap)> {
-    let mut token_map = TokenMap::default();
-    let tt = convert_tt(&mut token_map, node.text_range().start(), node)?;
-    Some((tt, token_map))
+    let global_offset = node.text_range().start();
+    let mut c = Convertor { map: TokenMap::default(), global_offset, next_id: 0 };
+    let subtree = c.go(node)?;
+    Some((subtree, c.map))
 }
 
 // The following items are what `rustc` macro can be parsed into :
@@ -55,7 +47,7 @@ pub fn syntax_node_to_token_tree(node: &SyntaxNode) -> Option<(tt::Subtree, Toke
 pub fn token_tree_to_syntax_node(
     tt: &tt::Subtree,
     fragment_kind: FragmentKind,
-) -> Result<(Parse<SyntaxNode>, RevTokenMap), ExpandError> {
+) -> Result<(Parse<SyntaxNode>, TokenMap), ExpandError> {
     let tmp;
     let tokens = match tt {
         tt::Subtree { delimiter: tt::Delimiter::None, token_trees } => token_trees.as_slice(),
@@ -78,31 +70,17 @@ pub fn token_tree_to_syntax_node(
 
 impl TokenMap {
     pub fn token_by_range(&self, relative_range: TextRange) -> Option<tt::TokenId> {
-        let (idx, _) =
-            self.tokens.iter().enumerate().find(|(_, range)| **range == relative_range)?;
-        Some(tt::TokenId(idx as u32))
-    }
-
-    pub fn relative_range_of(&self, token_id: tt::TokenId) -> Option<TextRange> {
-        let idx = token_id.0 as usize;
-        self.tokens.get(idx).copied()
-    }
-
-    fn alloc(&mut self, relative_range: TextRange) -> tt::TokenId {
-        let id = self.tokens.len();
-        self.tokens.push(relative_range);
-        tt::TokenId(id as u32)
+        let &(token_id, _) = self.entries.iter().find(|(_, range)| *range == relative_range)?;
+        Some(token_id)
     }
-}
 
-impl RevTokenMap {
     pub fn range_by_token(&self, token_id: tt::TokenId) -> Option<TextRange> {
-        let &(r, _) = self.ranges.iter().find(|(_, tid)| *tid == token_id)?;
-        Some(r)
+        let &(_, range) = self.entries.iter().find(|(tid, _)| *tid == token_id)?;
+        Some(range)
     }
 
-    fn add(&mut self, relative_range: TextRange, token_id: tt::TokenId) {
-        self.ranges.push((relative_range, token_id.clone()))
+    fn insert(&mut self, token_id: tt::TokenId, relative_range: TextRange) {
+        self.entries.push((token_id, relative_range));
     }
 }
 
@@ -167,84 +145,98 @@ fn convert_doc_comment(token: &ra_syntax::SyntaxToken) -> Option<Vec<tt::TokenTr
     }
 }
 
-fn convert_tt(
-    token_map: &mut TokenMap,
+struct Convertor {
+    map: TokenMap,
     global_offset: TextUnit,
-    tt: &SyntaxNode,
-) -> Option<tt::Subtree> {
-    // This tree is empty
-    if tt.first_child_or_token().is_none() {
-        return Some(tt::Subtree { token_trees: vec![], delimiter: tt::Delimiter::None });
-    }
+    next_id: u32,
+}
 
-    let first_child = tt.first_child_or_token()?;
-    let last_child = tt.last_child_or_token()?;
-    let (delimiter, skip_first) = match (first_child.kind(), last_child.kind()) {
-        (T!['('], T![')']) => (tt::Delimiter::Parenthesis, true),
-        (T!['{'], T!['}']) => (tt::Delimiter::Brace, true),
-        (T!['['], T![']']) => (tt::Delimiter::Bracket, true),
-        _ => (tt::Delimiter::None, false),
-    };
+impl Convertor {
+    fn go(&mut self, tt: &SyntaxNode) -> Option<tt::Subtree> {
+        // This tree is empty
+        if tt.first_child_or_token().is_none() {
+            return Some(tt::Subtree { token_trees: vec![], delimiter: tt::Delimiter::None });
+        }
 
-    let mut token_trees = Vec::new();
-    let mut child_iter = tt.children_with_tokens().skip(skip_first as usize).peekable();
+        let first_child = tt.first_child_or_token()?;
+        let last_child = tt.last_child_or_token()?;
+        let (delimiter, skip_first) = match (first_child.kind(), last_child.kind()) {
+            (T!['('], T![')']) => (tt::Delimiter::Parenthesis, true),
+            (T!['{'], T!['}']) => (tt::Delimiter::Brace, true),
+            (T!['['], T![']']) => (tt::Delimiter::Bracket, true),
+            _ => (tt::Delimiter::None, false),
+        };
 
-    while let Some(child) = child_iter.next() {
-        if skip_first && (child == first_child || child == last_child) {
-            continue;
-        }
+        let mut token_trees = Vec::new();
+        let mut child_iter = tt.children_with_tokens().skip(skip_first as usize).peekable();
 
-        match child {
-            NodeOrToken::Token(token) => {
-                if let Some(doc_tokens) = convert_doc_comment(&token) {
-                    token_trees.extend(doc_tokens);
-                } else if token.kind().is_trivia() {
-                    continue;
-                } else if token.kind().is_punct() {
-                    assert!(token.text().len() == 1, "Input ast::token punct must be single char.");
-                    let char = token.text().chars().next().unwrap();
-
-                    let spacing = match child_iter.peek() {
-                        Some(NodeOrToken::Token(token)) => {
-                            if token.kind().is_punct() {
-                                tt::Spacing::Joint
-                            } else {
-                                tt::Spacing::Alone
+        while let Some(child) = child_iter.next() {
+            if skip_first && (child == first_child || child == last_child) {
+                continue;
+            }
+
+            match child {
+                NodeOrToken::Token(token) => {
+                    if let Some(doc_tokens) = convert_doc_comment(&token) {
+                        token_trees.extend(doc_tokens);
+                    } else if token.kind().is_trivia() {
+                        continue;
+                    } else if token.kind().is_punct() {
+                        assert!(
+                            token.text().len() == 1,
+                            "Input ast::token punct must be single char."
+                        );
+                        let char = token.text().chars().next().unwrap();
+
+                        let spacing = match child_iter.peek() {
+                            Some(NodeOrToken::Token(token)) => {
+                                if token.kind().is_punct() {
+                                    tt::Spacing::Joint
+                                } else {
+                                    tt::Spacing::Alone
+                                }
                             }
-                        }
-                        _ => tt::Spacing::Alone,
-                    };
-
-                    token_trees.push(tt::Leaf::from(tt::Punct { char, spacing }).into());
-                } else {
-                    let child: tt::TokenTree =
-                        if token.kind() == T![true] || token.kind() == T![false] {
-                            tt::Leaf::from(tt::Literal { text: token.text().clone() }).into()
-                        } else if token.kind().is_keyword()
-                            || token.kind() == IDENT
-                            || token.kind() == LIFETIME
-                        {
-                            let relative_range = token.text_range() - global_offset;
-                            let id = token_map.alloc(relative_range);
-                            let text = token.text().clone();
-                            tt::Leaf::from(tt::Ident { text, id }).into()
-                        } else if token.kind().is_literal() {
-                            tt::Leaf::from(tt::Literal { text: token.text().clone() }).into()
-                        } else {
-                            return None;
+                            _ => tt::Spacing::Alone,
                         };
+
+                        token_trees.push(tt::Leaf::from(tt::Punct { char, spacing }).into());
+                    } else {
+                        let child: tt::TokenTree =
+                            if token.kind() == T![true] || token.kind() == T![false] {
+                                tt::Leaf::from(tt::Literal { text: token.text().clone() }).into()
+                            } else if token.kind().is_keyword()
+                                || token.kind() == IDENT
+                                || token.kind() == LIFETIME
+                            {
+                                let id = self.alloc(token.text_range());
+                                let text = token.text().clone();
+                                tt::Leaf::from(tt::Ident { text, id }).into()
+                            } else if token.kind().is_literal() {
+                                tt::Leaf::from(tt::Literal { text: token.text().clone() }).into()
+                            } else {
+                                return None;
+                            };
+                        token_trees.push(child);
+                    }
+                }
+                NodeOrToken::Node(node) => {
+                    let child = self.go(&node)?.into();
                     token_trees.push(child);
                 }
-            }
-            NodeOrToken::Node(node) => {
-                let child = convert_tt(token_map, global_offset, &node)?.into();
-                token_trees.push(child);
-            }
-        };
+            };
+        }
+
+        let res = tt::Subtree { delimiter, token_trees };
+        Some(res)
     }
 
-    let res = tt::Subtree { delimiter, token_trees };
-    Some(res)
+    fn alloc(&mut self, absolute_range: TextRange) -> tt::TokenId {
+        let relative_range = absolute_range - self.global_offset;
+        let token_id = tt::TokenId(self.next_id);
+        self.next_id += 1;
+        self.map.insert(token_id, relative_range);
+        token_id
+    }
 }
 
 struct TtTreeSink<'a> {
@@ -252,7 +244,7 @@ struct TtTreeSink<'a> {
     cursor: Cursor<'a>,
     text_pos: TextUnit,
     inner: SyntaxTreeBuilder,
-    range_map: RevTokenMap,
+    token_map: TokenMap,
 
     // Number of roots
     // Use for detect ill-form tree which is not single root
@@ -267,12 +259,12 @@ impl<'a> TtTreeSink<'a> {
             text_pos: 0.into(),
             inner: SyntaxTreeBuilder::default(),
             roots: smallvec::SmallVec::new(),
-            range_map: RevTokenMap::default(),
+            token_map: TokenMap::default(),
         }
     }
 
-    fn finish(self) -> (Parse<SyntaxNode>, RevTokenMap) {
-        (self.inner.finish(), self.range_map)
+    fn finish(self) -> (Parse<SyntaxNode>, TokenMap) {
+        (self.inner.finish(), self.token_map)
     }
 }
 
@@ -308,7 +300,7 @@ impl<'a> TreeSink for TtTreeSink<'a> {
                         if kind == IDENT {
                             let range =
                                 TextRange::offset_len(self.text_pos, TextUnit::of_str(&ident.text));
-                            self.range_map.add(range, ident.id);
+                            self.token_map.insert(ident.id, range);
                         }
                     }
 
diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index cefc00402..761b2435c 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -2,7 +2,7 @@
 //! Extensions for various expressions live in a sibling `expr_extensions` module.
 
 use crate::{
-    ast::{self, child_opt, children, AstChildren, AstNode, AttrInput, SyntaxNode},
+    ast::{self, child_opt, children, AstNode, AttrInput, SyntaxNode},
     SmolStr, SyntaxElement,
     SyntaxKind::*,
     SyntaxToken, T,
@@ -176,16 +176,6 @@ impl ast::ImplBlock {
     }
 }
 
-impl ast::AttrsOwner for ast::ImplItem {
-    fn attrs(&self) -> AstChildren<ast::Attr> {
-        match self {
-            ast::ImplItem::FnDef(it) => it.attrs(),
-            ast::ImplItem::TypeAliasDef(it) => it.attrs(),
-            ast::ImplItem::ConstDef(it) => it.attrs(),
-        }
-    }
-}
-
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum StructKind {
     Tuple(ast::TupleFieldDefList),
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 34b22c3e2..2b381dcdb 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -1298,6 +1298,7 @@ impl AstNode for ImplItem {
         }
     }
 }
+impl ast::AttrsOwner for ImplItem {}
 impl ImplItem {}
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct ImplTraitType {
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 0a8fd0612..70d85a8e6 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -401,7 +401,8 @@ Grammar(
             traits: ["AttrsOwner"]
         ),
         "ImplItem": (
-            enum: ["FnDef", "TypeAliasDef", "ConstDef"]
+            enum: ["FnDef", "TypeAliasDef", "ConstDef"],
+            traits: ["AttrsOwner"]
         ),
 
         "TupleExpr": (