Merge remote-tracking branch 'upstream/master' into 503-hover-doc-links

Hasn't fixed tests yet.

30 files changed, 2938 insertions, 2591 deletions

diff --git a/crates/ra_hir_def/src/adt.rs b/crates/ra_hir_def/src/adt.rs
index 4994a2125..6cb56a1cd 100644
--- a/crates/ra_hir_def/src/adt.rs
+++ b/crates/ra_hir_def/src/adt.rs
@@ -8,7 +8,7 @@ use hir_expand::{
     InFile,
 };
 use ra_arena::{map::ArenaMap, Arena};
-use ra_syntax::ast::{self, NameOwner, TypeAscriptionOwner, VisibilityOwner};
+use ra_syntax::ast::{self, NameOwner, VisibilityOwner};
 
 use crate::{
     body::{CfgExpander, LowerCtx},
@@ -112,7 +112,7 @@ impl EnumData {
 
 impl HasChildSource for EnumId {
     type ChildId = LocalEnumVariantId;
-    type Value = ast::EnumVariant;
+    type Value = ast::Variant;
     fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<Self::ChildId, Self::Value>> {
         let src = self.lookup(db).source(db);
         let mut trace = Trace::new_for_map();
@@ -123,8 +123,8 @@ impl HasChildSource for EnumId {
 
 fn lower_enum(
     db: &dyn DefDatabase,
-    trace: &mut Trace<EnumVariantData, ast::EnumVariant>,
-    ast: &InFile<ast::EnumDef>,
+    trace: &mut Trace<EnumVariantData, ast::Variant>,
+    ast: &InFile<ast::Enum>,
     module_id: ModuleId,
 ) {
     let expander = CfgExpander::new(db, ast.file_id, module_id.krate);
@@ -179,7 +179,7 @@ impl VariantData {
 
 impl HasChildSource for VariantId {
     type ChildId = LocalFieldId;
-    type Value = Either<ast::TupleFieldDef, ast::RecordFieldDef>;
+    type Value = Either<ast::TupleField, ast::RecordField>;
 
     fn child_source(&self, db: &dyn DefDatabase) -> InFile<ArenaMap<Self::ChildId, Self::Value>> {
         let (src, module_id) = match self {
@@ -194,7 +194,7 @@ impl HasChildSource for VariantId {
             }
             VariantId::UnionId(it) => (
                 it.lookup(db).source(db).map(|it| {
-                    it.record_field_def_list()
+                    it.record_field_list()
                         .map(ast::StructKind::Record)
                         .unwrap_or(ast::StructKind::Unit)
                 }),
@@ -218,7 +218,7 @@ pub enum StructKind {
 fn lower_struct(
     db: &dyn DefDatabase,
     expander: &mut CfgExpander,
-    trace: &mut Trace<FieldData, Either<ast::TupleFieldDef, ast::RecordFieldDef>>,
+    trace: &mut Trace<FieldData, Either<ast::TupleField, ast::RecordField>>,
     ast: &InFile<ast::StructKind>,
 ) -> StructKind {
     let ctx = LowerCtx::new(db, ast.file_id);
@@ -234,7 +234,7 @@ fn lower_struct(
                     || Either::Left(fd.clone()),
                     || FieldData {
                         name: Name::new_tuple_field(i),
-                        type_ref: TypeRef::from_ast_opt(&ctx, fd.type_ref()),
+                        type_ref: TypeRef::from_ast_opt(&ctx, fd.ty()),
                         visibility: RawVisibility::from_ast(db, ast.with_value(fd.visibility())),
                     },
                 );
@@ -251,7 +251,7 @@ fn lower_struct(
                     || Either::Right(fd.clone()),
                     || FieldData {
                         name: fd.name().map(|n| n.as_name()).unwrap_or_else(Name::missing),
-                        type_ref: TypeRef::from_ast_opt(&ctx, fd.ascribed_type()),
+                        type_ref: TypeRef::from_ast_opt(&ctx, fd.ty()),
                         visibility: RawVisibility::from_ast(db, ast.with_value(fd.visibility())),
                     },
                 );
diff --git a/crates/ra_hir_def/src/attr.rs b/crates/ra_hir_def/src/attr.rs
index e228e2145..050832ce0 100644
--- a/crates/ra_hir_def/src/attr.rs
+++ b/crates/ra_hir_def/src/attr.rs
@@ -5,7 +5,7 @@ use std::{ops, sync::Arc};
 use either::Either;
 use hir_expand::{hygiene::Hygiene, AstId, InFile};
 use mbe::ast_to_token_tree;
-use ra_cfg::CfgOptions;
+use ra_cfg::{CfgExpr, CfgOptions};
 use ra_syntax::{
     ast::{self, AstNode, AttrsOwner},
     SmolStr,
@@ -125,9 +125,12 @@ impl Attrs {
         AttrQuery { attrs: self, key }
     }
 
-    pub(crate) fn is_cfg_enabled(&self, cfg_options: &CfgOptions) -> bool {
+    pub fn cfg(&self) -> impl Iterator<Item = CfgExpr> + '_ {
         // FIXME: handle cfg_attr :-)
-        self.by_key("cfg").tt_values().all(|tt| cfg_options.is_cfg_enabled(tt) != Some(false))
+        self.by_key("cfg").tt_values().map(CfgExpr::parse)
+    }
+    pub(crate) fn is_cfg_enabled(&self, cfg_options: &CfgOptions) -> bool {
+        self.cfg().all(|cfg| cfg_options.check(&cfg) != Some(false))
     }
 }
 
@@ -148,18 +151,15 @@ pub enum AttrInput {
 impl Attr {
     fn from_src(ast: ast::Attr, hygiene: &Hygiene) -> Option<Attr> {
         let path = ModPath::from_src(ast.path()?, hygiene)?;
-        let input = match ast.input() {
-            None => None,
-            Some(ast::AttrInput::Literal(lit)) => {
-                // FIXME: escape? raw string?
-                let value = lit.syntax().first_token()?.text().trim_matches('"').into();
-                Some(AttrInput::Literal(value))
-            }
-            Some(ast::AttrInput::TokenTree(tt)) => {
-                Some(AttrInput::TokenTree(ast_to_token_tree(&tt)?.0))
-            }
+        let input = if let Some(lit) = ast.literal() {
+            // FIXME: escape? raw string?
+            let value = lit.syntax().first_token()?.text().trim_matches('"').into();
+            Some(AttrInput::Literal(value))
+        } else if let Some(tt) = ast.token_tree() {
+            Some(AttrInput::TokenTree(ast_to_token_tree(&tt)?.0))
+        } else {
+            None
         };
-
         Some(Attr { path, input })
     }
 }
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 4f2350915..d5f18b920 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -14,6 +14,7 @@ use ra_db::CrateId;
 use ra_prof::profile;
 use ra_syntax::{ast, AstNode, AstPtr};
 use rustc_hash::FxHashMap;
+use test_utils::mark;
 
 pub(crate) use lower::LowerCtx;
 
@@ -42,9 +43,15 @@ pub(crate) struct Expander {
     current_file_id: HirFileId,
     ast_id_map: Arc<AstIdMap>,
     module: ModuleId,
-    recursive_limit: usize,
+    recursion_limit: usize,
 }
 
+#[cfg(test)]
+const EXPANSION_RECURSION_LIMIT: usize = 32;
+
+#[cfg(not(test))]
+const EXPANSION_RECURSION_LIMIT: usize = 128;
+
 impl CfgExpander {
     pub(crate) fn new(
         db: &dyn DefDatabase,
@@ -81,7 +88,7 @@ impl Expander {
             current_file_id,
             ast_id_map,
             module,
-            recursive_limit: 0,
+            recursion_limit: 0,
         }
     }
 
@@ -91,7 +98,9 @@ impl Expander {
         local_scope: Option<&ItemScope>,
         macro_call: ast::MacroCall,
     ) -> Option<(Mark, T)> {
-        if self.recursive_limit > 1024 {
+        self.recursion_limit += 1;
+        if self.recursion_limit > EXPANSION_RECURSION_LIMIT {
+            mark::hit!(your_stack_belongs_to_me);
             return None;
         }
 
@@ -118,8 +127,6 @@ impl Expander {
                     self.cfg_expander.hygiene = Hygiene::new(db.upcast(), file_id);
                     self.current_file_id = file_id;
                     self.ast_id_map = db.ast_id_map(file_id);
-                    self.recursive_limit += 1;
-
                     return Some((mark, expr));
                 }
             }
@@ -134,7 +141,7 @@ impl Expander {
         self.cfg_expander.hygiene = Hygiene::new(db.upcast(), mark.file_id);
         self.current_file_id = mark.file_id;
         self.ast_id_map = mem::take(&mut mark.ast_id_map);
-        self.recursive_limit -= 1;
+        self.recursion_limit -= 1;
         mark.bomb.defuse();
     }
 
@@ -209,7 +216,7 @@ pub struct BodySourceMap {
     expr_map_back: ArenaMap<ExprId, Result<ExprSource, SyntheticSyntax>>,
     pat_map: FxHashMap<PatSource, PatId>,
     pat_map_back: ArenaMap<PatId, Result<PatSource, SyntheticSyntax>>,
-    field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordField>>>,
+    field_map: FxHashMap<(ExprId, usize), InFile<AstPtr<ast::RecordExprField>>>,
     expansions: FxHashMap<InFile<AstPtr<ast::MacroCall>>, HirFileId>,
 }
 
@@ -302,7 +309,53 @@ impl BodySourceMap {
         self.pat_map.get(&src).cloned()
     }
 
-    pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordField>> {
+    pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
+        let src = node.map(|it| Either::Right(AstPtr::new(it)));
+        self.pat_map.get(&src).cloned()
+    }
+
+    pub fn field_syntax(&self, expr: ExprId, field: usize) -> InFile<AstPtr<ast::RecordExprField>> {
         self.field_map[&(expr, field)].clone()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use ra_db::{fixture::WithFixture, SourceDatabase};
+    use test_utils::mark;
+
+    use crate::ModuleDefId;
+
+    use super::*;
+
+    fn lower(ra_fixture: &str) -> Arc<Body> {
+        let (db, file_id) = crate::test_db::TestDB::with_single_file(ra_fixture);
+
+        let krate = db.crate_graph().iter().next().unwrap();
+        let def_map = db.crate_def_map(krate);
+        let module = def_map.modules_for_file(file_id).next().unwrap();
+        let module = &def_map[module];
+        let fn_def = match module.scope.declarations().next().unwrap() {
+            ModuleDefId::FunctionId(it) => it,
+            _ => panic!(),
+        };
+
+        db.body(fn_def.into())
+    }
+
+    #[test]
+    fn your_stack_belongs_to_me() {
+        mark::check!(your_stack_belongs_to_me);
+        lower(
+            "
+macro_rules! n_nuple {
+    ($e:tt) => ();
+    ($($rest:tt)*) => {{
+        (n_nuple!($($rest)*)None,)
+    }};
+}
+fn main() { n_nuple!(1,2,3); }
+",
+        );
+    }
+}
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index c6bc85e2f..827ced4ad 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -11,7 +11,7 @@ use ra_arena::Arena;
 use ra_syntax::{
     ast::{
         self, ArgListOwner, ArrayExprKind, LiteralKind, LoopBodyOwner, ModuleItemOwner, NameOwner,
-        SlicePatComponents, TypeAscriptionOwner,
+        SlicePatComponents,
     },
     AstNode, AstPtr,
 };
@@ -379,10 +379,10 @@ impl ExprCollector<'_> {
                 let expr = e.expr().map(|e| self.collect_expr(e));
                 self.alloc_expr(Expr::Return { expr }, syntax_ptr)
             }
-            ast::Expr::RecordLit(e) => {
+            ast::Expr::RecordExpr(e) => {
                 let path = e.path().and_then(|path| self.expander.parse_path(path));
                 let mut field_ptrs = Vec::new();
-                let record_lit = if let Some(nfl) = e.record_field_list() {
+                let record_lit = if let Some(nfl) = e.record_expr_field_list() {
                     let fields = nfl
                         .fields()
                         .inspect(|field| field_ptrs.push(AstPtr::new(field)))
@@ -432,7 +432,7 @@ impl ExprCollector<'_> {
             }
             ast::Expr::CastExpr(e) => {
                 let expr = self.collect_expr_opt(e.expr());
-                let type_ref = TypeRef::from_ast_opt(&self.ctx(), e.type_ref());
+                let type_ref = TypeRef::from_ast_opt(&self.ctx(), e.ty());
                 self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
             }
             ast::Expr::RefExpr(e) => {
@@ -466,16 +466,13 @@ impl ExprCollector<'_> {
                 if let Some(pl) = e.param_list() {
                     for param in pl.params() {
                         let pat = self.collect_pat_opt(param.pat());
-                        let type_ref =
-                            param.ascribed_type().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                        let type_ref = param.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
                         args.push(pat);
                         arg_types.push(type_ref);
                     }
                 }
-                let ret_type = e
-                    .ret_type()
-                    .and_then(|r| r.type_ref())
-                    .map(|it| TypeRef::from_ast(&self.ctx(), it));
+                let ret_type =
+                    e.ret_type().and_then(|r| r.ty()).map(|it| TypeRef::from_ast(&self.ctx(), it));
                 let body = self.collect_expr_opt(e.body());
                 self.alloc_expr(Expr::Lambda { args, arg_types, ret_type, body }, syntax_ptr)
             }
@@ -607,8 +604,7 @@ impl ExprCollector<'_> {
             .map(|s| match s {
                 ast::Stmt::LetStmt(stmt) => {
                     let pat = self.collect_pat_opt(stmt.pat());
-                    let type_ref =
-                        stmt.ascribed_type().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                    let type_ref = stmt.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
                     let initializer = stmt.initializer().map(|e| self.collect_expr(e));
                     Statement::Let { pat, type_ref, initializer }
                 }
@@ -627,53 +623,53 @@ impl ExprCollector<'_> {
             .items()
             .filter_map(|item| {
                 let (def, name): (ModuleDefId, Option<ast::Name>) = match item {
-                    ast::ModuleItem::FnDef(def) => {
+                    ast::Item::Fn(def) => {
                         let id = self.find_inner_item(&def)?;
                         (
                             FunctionLoc { container: container.into(), id }.intern(self.db).into(),
                             def.name(),
                         )
                     }
-                    ast::ModuleItem::TypeAliasDef(def) => {
+                    ast::Item::TypeAlias(def) => {
                         let id = self.find_inner_item(&def)?;
                         (
                             TypeAliasLoc { container: container.into(), id }.intern(self.db).into(),
                             def.name(),
                         )
                     }
-                    ast::ModuleItem::ConstDef(def) => {
+                    ast::Item::Const(def) => {
                         let id = self.find_inner_item(&def)?;
                         (
                             ConstLoc { container: container.into(), id }.intern(self.db).into(),
                             def.name(),
                         )
                     }
-                    ast::ModuleItem::StaticDef(def) => {
+                    ast::Item::Static(def) => {
                         let id = self.find_inner_item(&def)?;
                         (StaticLoc { container, id }.intern(self.db).into(), def.name())
                     }
-                    ast::ModuleItem::StructDef(def) => {
+                    ast::Item::Struct(def) => {
                         let id = self.find_inner_item(&def)?;
                         (StructLoc { container, id }.intern(self.db).into(), def.name())
                     }
-                    ast::ModuleItem::EnumDef(def) => {
+                    ast::Item::Enum(def) => {
                         let id = self.find_inner_item(&def)?;
                         (EnumLoc { container, id }.intern(self.db).into(), def.name())
                     }
-                    ast::ModuleItem::UnionDef(def) => {
+                    ast::Item::Union(def) => {
                         let id = self.find_inner_item(&def)?;
                         (UnionLoc { container, id }.intern(self.db).into(), def.name())
                     }
-                    ast::ModuleItem::TraitDef(def) => {
+                    ast::Item::Trait(def) => {
                         let id = self.find_inner_item(&def)?;
                         (TraitLoc { container, id }.intern(self.db).into(), def.name())
                     }
-                    ast::ModuleItem::ExternBlock(_) => return None, // FIXME: collect from extern blocks
-                    ast::ModuleItem::ImplDef(_)
-                    | ast::ModuleItem::UseItem(_)
-                    | ast::ModuleItem::ExternCrateItem(_)
-                    | ast::ModuleItem::Module(_)
-                    | ast::ModuleItem::MacroCall(_) => return None,
+                    ast::Item::ExternBlock(_) => return None, // FIXME: collect from extern blocks
+                    ast::Item::Impl(_)
+                    | ast::Item::Use(_)
+                    | ast::Item::ExternCrate(_)
+                    | ast::Item::Module(_)
+                    | ast::Item::MacroCall(_) => return None,
                 };
 
                 Some((def, name))
diff --git a/crates/ra_hir_def/src/child_by_source.rs b/crates/ra_hir_def/src/child_by_source.rs
index a885ec96d..dcb00a1d9 100644
--- a/crates/ra_hir_def/src/child_by_source.rs
+++ b/crates/ra_hir_def/src/child_by_source.rs
@@ -162,7 +162,7 @@ impl ChildBySource for EnumId {
         let arena_map = arena_map.as_ref();
         for (local_id, source) in arena_map.value.iter() {
             let id = EnumVariantId { parent: *self, local_id };
-            res[keys::ENUM_VARIANT].insert(arena_map.with_value(source.clone()), id)
+            res[keys::VARIANT].insert(arena_map.with_value(source.clone()), id)
         }
 
         res
diff --git a/crates/ra_hir_def/src/data.rs b/crates/ra_hir_def/src/data.rs
index 282ade2a3..88a8ef9bf 100644
--- a/crates/ra_hir_def/src/data.rs
+++ b/crates/ra_hir_def/src/data.rs
@@ -27,11 +27,12 @@ pub struct FunctionData {
     /// can be called as a method.
     pub has_self_param: bool,
     pub is_unsafe: bool,
+    pub is_varargs: bool,
     pub visibility: RawVisibility,
 }
 
 impl FunctionData {
-    pub(crate) fn fn_data_query(db: &impl DefDatabase, func: FunctionId) -> Arc<FunctionData> {
+    pub(crate) fn fn_data_query(db: &dyn DefDatabase, func: FunctionId) -> Arc<FunctionData> {
         let loc = func.lookup(db);
         let item_tree = db.item_tree(loc.id.file_id);
         let func = &item_tree[loc.id.value];
@@ -43,6 +44,7 @@ impl FunctionData {
             attrs: item_tree.attrs(ModItem::from(loc.id.value).into()).clone(),
             has_self_param: func.has_self_param,
             is_unsafe: func.is_unsafe,
+            is_varargs: func.is_varargs,
             visibility: item_tree[func.visibility].clone(),
         })
     }
diff --git a/crates/ra_hir_def/src/generics.rs b/crates/ra_hir_def/src/generics.rs
index 6a0f493a7..8ea61fcf2 100644
--- a/crates/ra_hir_def/src/generics.rs
+++ b/crates/ra_hir_def/src/generics.rs
@@ -12,7 +12,7 @@ use hir_expand::{
 use ra_arena::{map::ArenaMap, Arena};
 use ra_db::FileId;
 use ra_prof::profile;
-use ra_syntax::ast::{self, NameOwner, TypeBoundsOwner, TypeParamsOwner};
+use ra_syntax::ast::{self, GenericParamsOwner, NameOwner, TypeBoundsOwner};
 
 use crate::{
     body::LowerCtx,
@@ -66,7 +66,7 @@ pub enum WherePredicateTarget {
     TypeParam(LocalTypeParamId),
 }
 
-type SourceMap = ArenaMap<LocalTypeParamId, Either<ast::TraitDef, ast::TypeParam>>;
+type SourceMap = ArenaMap<LocalTypeParamId, Either<ast::Trait, ast::TypeParam>>;
 
 impl GenericParams {
     pub(crate) fn generic_params_query(
@@ -205,9 +205,9 @@ impl GenericParams {
         &mut self,
         lower_ctx: &LowerCtx,
         sm: &mut SourceMap,
-        node: &dyn TypeParamsOwner,
+        node: &dyn GenericParamsOwner,
     ) {
-        if let Some(params) = node.type_param_list() {
+        if let Some(params) = node.generic_param_list() {
             self.fill_params(lower_ctx, sm, params)
         }
         if let Some(where_clause) = node.where_clause() {
@@ -232,7 +232,7 @@ impl GenericParams {
         &mut self,
         lower_ctx: &LowerCtx,
         sm: &mut SourceMap,
-        params: ast::TypeParamList,
+        params: ast::GenericParamList,
     ) {
         for type_param in params.type_params() {
             let name = type_param.name().map_or_else(Name::missing, |it| it.as_name());
@@ -317,7 +317,7 @@ impl GenericParams {
 
 impl HasChildSource for GenericDefId {
     type ChildId = LocalTypeParamId;
-    type Value = Either<ast::TraitDef, ast::TypeParam>;
+    type Value = Either<ast::Trait, ast::TypeParam>;
     fn child_source(&self, db: &dyn DefDatabase) -> InFile<SourceMap> {
         let (_, sm) = GenericParams::new(db, *self);
         sm
diff --git a/crates/ra_hir_def/src/import_map.rs b/crates/ra_hir_def/src/import_map.rs
index 68e20d06b..9e4c30b1a 100644
--- a/crates/ra_hir_def/src/import_map.rs
+++ b/crates/ra_hir_def/src/import_map.rs
@@ -5,14 +5,16 @@ use std::{cmp::Ordering, fmt, hash::BuildHasherDefault, sync::Arc};
 use fst::{self, Streamer};
 use indexmap::{map::Entry, IndexMap};
 use ra_db::CrateId;
-use rustc_hash::FxHasher;
+use ra_syntax::SmolStr;
+use rustc_hash::{FxHashMap, FxHasher};
+use smallvec::SmallVec;
 
 use crate::{
     db::DefDatabase,
     item_scope::ItemInNs,
     path::{ModPath, PathKind},
     visibility::Visibility,
-    ModuleDefId, ModuleId,
+    AssocItemId, ModuleDefId, ModuleId, TraitId,
 };
 
 type FxIndexMap<K, V> = IndexMap<K, V, BuildHasherDefault<FxHasher>>;
@@ -34,6 +36,7 @@ pub struct ImportInfo {
 ///
 /// Note that all paths are relative to the containing crate's root, so the crate name still needs
 /// to be prepended to the `ModPath` before the path is valid.
+#[derive(Default)]
 pub struct ImportMap {
     map: FxIndexMap<ItemInNs, ImportInfo>,
 
@@ -45,13 +48,17 @@ pub struct ImportMap {
     /// the index of the first one.
     importables: Vec<ItemInNs>,
     fst: fst::Map<Vec<u8>>,
+
+    /// Maps names of associated items to the item's ID. Only includes items whose defining trait is
+    /// exported.
+    assoc_map: FxHashMap<SmolStr, SmallVec<[AssocItemId; 1]>>,
 }
 
 impl ImportMap {
     pub fn import_map_query(db: &dyn DefDatabase, krate: CrateId) -> Arc<Self> {
         let _p = ra_prof::profile("import_map_query");
         let def_map = db.crate_def_map(krate);
-        let mut import_map = FxIndexMap::with_capacity_and_hasher(64, Default::default());
+        let mut import_map = Self::default();
 
         // We look only into modules that are public(ly reexported), starting with the crate root.
         let empty = ModPath { kind: PathKind::Plain, segments: vec![] };
@@ -85,7 +92,7 @@ impl ImportMap {
 
                 for item in per_ns.iter_items() {
                     let path = mk_path();
-                    match import_map.entry(item) {
+                    match import_map.map.entry(item) {
                         Entry::Vacant(entry) => {
                             entry.insert(ImportInfo { path, container: module });
                         }
@@ -105,11 +112,16 @@ impl ImportMap {
                     if let Some(ModuleDefId::ModuleId(mod_id)) = item.as_module_def_id() {
                         worklist.push((mod_id, mk_path()));
                     }
+
+                    // If we've added a path to a trait, add the trait's methods to the method map.
+                    if let Some(ModuleDefId::TraitId(tr)) = item.as_module_def_id() {
+                        import_map.collect_trait_methods(db, tr);
+                    }
                 }
             }
         }
 
-        let mut importables = import_map.iter().collect::<Vec<_>>();
+        let mut importables = import_map.map.iter().collect::<Vec<_>>();
 
         importables.sort_by(cmp);
 
@@ -133,10 +145,10 @@ impl ImportMap {
             builder.insert(key, start as u64).unwrap();
         }
 
-        let fst = fst::Map::new(builder.into_inner().unwrap()).unwrap();
-        let importables = importables.iter().map(|(item, _)| **item).collect();
+        import_map.fst = fst::Map::new(builder.into_inner().unwrap()).unwrap();
+        import_map.importables = importables.iter().map(|(item, _)| **item).collect();
 
-        Arc::new(Self { map: import_map, fst, importables })
+        Arc::new(import_map)
     }
 
     /// Returns the `ModPath` needed to import/mention `item`, relative to this crate's root.
@@ -147,6 +159,13 @@ impl ImportMap {
     pub fn import_info_for(&self, item: ItemInNs) -> Option<&ImportInfo> {
         self.map.get(&item)
     }
+
+    fn collect_trait_methods(&mut self, db: &dyn DefDatabase, tr: TraitId) {
+        let data = db.trait_data(tr);
+        for (name, item) in data.items.iter() {
+            self.assoc_map.entry(name.to_string().into()).or_default().push(*item);
+        }
+    }
 }
 
 impl PartialEq for ImportMap {
@@ -290,37 +309,32 @@ pub fn search_dependencies<'a>(
         }
     }
 
+    // Add all exported associated items whose names match the query (exactly).
+    for map in &import_maps {
+        if let Some(v) = map.assoc_map.get(&*query.query) {
+            res.extend(v.iter().map(|&assoc| {
+                ItemInNs::Types(match assoc {
+                    AssocItemId::FunctionId(it) => it.into(),
+                    AssocItemId::ConstId(it) => it.into(),
+                    AssocItemId::TypeAliasId(it) => it.into(),
+                })
+            }));
+        }
+    }
+
     res
 }
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::test_db::TestDB;
-    use insta::assert_snapshot;
-    use itertools::Itertools;
-    use ra_db::fixture::WithFixture;
-    use ra_db::{SourceDatabase, Upcast};
+    use expect::{expect, Expect};
+    use ra_db::{fixture::WithFixture, SourceDatabase, Upcast};
 
-    fn import_map(ra_fixture: &str) -> String {
-        let db = TestDB::with_files(ra_fixture);
-        let crate_graph = db.crate_graph();
+    use crate::{test_db::TestDB, AssocContainerId, Lookup};
 
-        let s = crate_graph
-            .iter()
-            .filter_map(|krate| {
-                let cdata = &crate_graph[krate];
-                let name = cdata.display_name.as_ref()?;
-
-                let map = db.import_map(krate);
-
-                Some(format!("{}:\n{:?}", name, map))
-            })
-            .join("\n");
-        s
-    }
+    use super::*;
 
-    fn search_dependencies_of(ra_fixture: &str, krate_name: &str, query: Query) -> String {
+    fn check_search(ra_fixture: &str, krate_name: &str, query: Query, expect: Expect) {
         let db = TestDB::with_files(ra_fixture);
         let crate_graph = db.crate_graph();
         let krate = crate_graph
@@ -331,7 +345,7 @@ mod tests {
             })
             .unwrap();
 
-        search_dependencies(db.upcast(), krate, query)
+        let actual = search_dependencies(db.upcast(), krate, query)
             .into_iter()
             .filter_map(|item| {
                 let mark = match item {
@@ -339,23 +353,67 @@ mod tests {
                     ItemInNs::Values(_) => "v",
                     ItemInNs::Macros(_) => "m",
                 };
+                let item = assoc_to_trait(&db, item);
                 item.krate(db.upcast()).map(|krate| {
                     let map = db.import_map(krate);
                     let path = map.path_of(item).unwrap();
                     format!(
-                        "{}::{} ({})",
+                        "{}::{} ({})\n",
                         crate_graph[krate].display_name.as_ref().unwrap(),
                         path,
                         mark
                     )
                 })
             })
-            .join("\n")
+            .collect::<String>();
+        expect.assert_eq(&actual)
+    }
+
+    fn assoc_to_trait(db: &dyn DefDatabase, item: ItemInNs) -> ItemInNs {
+        let assoc: AssocItemId = match item {
+            ItemInNs::Types(it) | ItemInNs::Values(it) => match it {
+                ModuleDefId::TypeAliasId(it) => it.into(),
+                ModuleDefId::FunctionId(it) => it.into(),
+                ModuleDefId::ConstId(it) => it.into(),
+                _ => return item,
+            },
+            _ => return item,
+        };
+
+        let container = match assoc {
+            AssocItemId::FunctionId(it) => it.lookup(db).container,
+            AssocItemId::ConstId(it) => it.lookup(db).container,
+            AssocItemId::TypeAliasId(it) => it.lookup(db).container,
+        };
+
+        match container {
+            AssocContainerId::TraitId(it) => ItemInNs::Types(it.into()),
+            _ => item,
+        }
+    }
+
+    fn check(ra_fixture: &str, expect: Expect) {
+        let db = TestDB::with_files(ra_fixture);
+        let crate_graph = db.crate_graph();
+
+        let actual = crate_graph
+            .iter()
+            .filter_map(|krate| {
+                let cdata = &crate_graph[krate];
+                let name = cdata.display_name.as_ref()?;
+
+                let map = db.import_map(krate);
+
+                Some(format!("{}:\n{:?}\n", name, map))
+            })
+            .collect::<String>();
+
+        expect.assert_eq(&actual)
     }
 
     #[test]
     fn smoke() {
-        let map = import_map(
+        check(
             r"
             //- /main.rs crate:main deps:lib
 
@@ -380,24 +438,23 @@ mod tests {
             pub struct Pub2; // t + v
             struct Priv;
         ",
+            expect![[r#"
+                main:
+                - publ1 (t)
+                - real_pu2 (t)
+                - real_pub (t)
+                - real_pub::Pub (t)
+                lib:
+                - Pub (t)
+                - Pub2 (t)
+                - Pub2 (v)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        main:
-        - publ1 (t)
-        - real_pu2 (t)
-        - real_pub (t)
-        - real_pub::Pub (t)
-        lib:
-        - Pub (t)
-        - Pub2 (t)
-        - Pub2 (v)
-        "###);
     }
 
     #[test]
     fn prefers_shortest_path() {
-        let map = import_map(
+        check(
             r"
             //- /main.rs crate:main
 
@@ -409,21 +466,20 @@ mod tests {
                 pub use super::sub::subsub::Def;
             }
         ",
+            expect![[r#"
+                main:
+                - sub (t)
+                - sub::Def (t)
+                - sub::subsub (t)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        main:
-        - sub (t)
-        - sub::Def (t)
-        - sub::subsub (t)
-        "###);
     }
 
     #[test]
     fn type_reexport_cross_crate() {
         // Reexports need to be visible from a crate, even if the original crate exports the item
         // at a shorter path.
-        let map = import_map(
+        check(
             r"
             //- /main.rs crate:main deps:lib
             pub mod m {
@@ -432,22 +488,21 @@ mod tests {
             //- /lib.rs crate:lib
             pub struct S;
         ",
+            expect![[r#"
+                main:
+                - m (t)
+                - m::S (t)
+                - m::S (v)
+                lib:
+                - S (t)
+                - S (v)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        main:
-        - m (t)
-        - m::S (t)
-        - m::S (v)
-        lib:
-        - S (t)
-        - S (v)
-        "###);
     }
 
     #[test]
     fn macro_reexport() {
-        let map = import_map(
+        check(
             r"
             //- /main.rs crate:main deps:lib
             pub mod m {
@@ -459,21 +514,20 @@ mod tests {
                 () => {};
             }
         ",
+            expect![[r#"
+                main:
+                - m (t)
+                - m::pub_macro (m)
+                lib:
+                - pub_macro (m)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        main:
-        - m (t)
-        - m::pub_macro (m)
-        lib:
-        - pub_macro (m)
-        "###);
     }
 
     #[test]
     fn module_reexport() {
         // Reexporting modules from a dependency adds all contents to the import map.
-        let map = import_map(
+        check(
             r"
             //- /main.rs crate:main deps:lib
             pub use lib::module as reexported_module;
@@ -482,24 +536,23 @@ mod tests {
                 pub struct S;
             }
         ",
+            expect![[r#"
+                main:
+                - reexported_module (t)
+                - reexported_module::S (t)
+                - reexported_module::S (v)
+                lib:
+                - module (t)
+                - module::S (t)
+                - module::S (v)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        main:
-        - reexported_module (t)
-        - reexported_module::S (t)
-        - reexported_module::S (v)
-        lib:
-        - module (t)
-        - module::S (t)
-        - module::S (v)
-        "###);
     }
 
     #[test]
     fn cyclic_module_reexport() {
         // A cyclic reexport does not hang.
-        let map = import_map(
+        check(
             r"
             //- /lib.rs crate:lib
             pub mod module {
@@ -511,36 +564,35 @@ mod tests {
                 pub use super::module;
             }
         ",
+            expect![[r#"
+                lib:
+                - module (t)
+                - module::S (t)
+                - module::S (v)
+                - sub (t)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        lib:
-        - module (t)
-        - module::S (t)
-        - module::S (v)
-        - sub (t)
-        "###);
     }
 
     #[test]
     fn private_macro() {
-        let map = import_map(
+        check(
             r"
             //- /lib.rs crate:lib
             macro_rules! private_macro {
                 () => {};
             }
         ",
-        );
+            expect![[r#"
+                lib:
 
-        assert_snapshot!(map, @r###"
-        lib:
-        "###);
+            "#]],
+        );
     }
 
     #[test]
     fn namespacing() {
-        let map = import_map(
+        check(
             r"
             //- /lib.rs crate:lib
             pub struct Thing;     // t + v
@@ -549,16 +601,15 @@ mod tests {
                 () => {};
             }
         ",
+            expect![[r#"
+                lib:
+                - Thing (m)
+                - Thing (t)
+                - Thing (v)
+            "#]],
         );
 
-        assert_snapshot!(map, @r###"
-        lib:
-        - Thing (m)
-        - Thing (t)
-        - Thing (v)
-        "###);
-
-        let map = import_map(
+        check(
             r"
             //- /lib.rs crate:lib
             pub mod Thing {}      // t
@@ -567,13 +618,12 @@ mod tests {
                 () => {};
             }
         ",
+            expect![[r#"
+                lib:
+                - Thing (m)
+                - Thing (t)
+            "#]],
         );
-
-        assert_snapshot!(map, @r###"
-        lib:
-        - Thing (m)
-        - Thing (t)
-        "###);
     }
 
     #[test]
@@ -602,23 +652,33 @@ mod tests {
             }
         "#;
 
-        let res = search_dependencies_of(ra_fixture, "main", Query::new("fmt"));
-        assert_snapshot!(res, @r###"
-        dep::fmt (t)
-        dep::Fmt (t)
-        dep::Fmt (v)
-        dep::Fmt (m)
-        dep::fmt::Display (t)
-        dep::format (v)
-        "###);
-
-        let res = search_dependencies_of(ra_fixture, "main", Query::new("fmt").anchor_end());
-        assert_snapshot!(res, @r###"
-        dep::fmt (t)
-        dep::Fmt (t)
-        dep::Fmt (v)
-        dep::Fmt (m)
-        "###);
+        check_search(
+            ra_fixture,
+            "main",
+            Query::new("fmt"),
+            expect![[r#"
+                dep::fmt (t)
+                dep::Fmt (t)
+                dep::Fmt (v)
+                dep::Fmt (m)
+                dep::fmt::Display (t)
+                dep::format (v)
+                dep::fmt::Display (t)
+            "#]],
+        );
+
+        check_search(
+            ra_fixture,
+            "main",
+            Query::new("fmt").anchor_end(),
+            expect![[r#"
+                dep::fmt (t)
+                dep::Fmt (t)
+                dep::Fmt (v)
+                dep::Fmt (m)
+                dep::fmt::Display (t)
+            "#]],
+        );
     }
 
     #[test]
@@ -631,26 +691,32 @@ mod tests {
             pub struct FMT;
         "#;
 
-        let res = search_dependencies_of(ra_fixture, "main", Query::new("FMT"));
-
-        assert_snapshot!(res, @r###"
-        dep::fmt (t)
-        dep::fmt (v)
-        dep::FMT (t)
-        dep::FMT (v)
-        "###);
-
-        let res = search_dependencies_of(ra_fixture, "main", Query::new("FMT").case_sensitive());
+        check_search(
+            ra_fixture,
+            "main",
+            Query::new("FMT"),
+            expect![[r#"
+                dep::fmt (t)
+                dep::fmt (v)
+                dep::FMT (t)
+                dep::FMT (v)
+            "#]],
+        );
 
-        assert_snapshot!(res, @r###"
-        dep::FMT (t)
-        dep::FMT (v)
-        "###);
+        check_search(
+            ra_fixture,
+            "main",
+            Query::new("FMT").case_sensitive(),
+            expect![[r#"
+                dep::FMT (t)
+                dep::FMT (v)
+            "#]],
+        );
     }
 
     #[test]
     fn search_limit() {
-        let res = search_dependencies_of(
+        check_search(
             r#"
         //- /main.rs crate:main deps:dep
         //- /dep.rs crate:dep
@@ -670,10 +736,10 @@ mod tests {
     "#,
             "main",
             Query::new("").limit(2),
+            expect![[r#"
+                dep::fmt (t)
+                dep::Fmt (t)
+            "#]],
         );
-        assert_snapshot!(res, @r###"
-        dep::fmt (t)
-        dep::Fmt (t)
-        "###);
     }
 }
diff --git a/crates/ra_hir_def/src/item_scope.rs b/crates/ra_hir_def/src/item_scope.rs
index 4d446c707..8fee4b15e 100644
--- a/crates/ra_hir_def/src/item_scope.rs
+++ b/crates/ra_hir_def/src/item_scope.rs
@@ -1,6 +1,8 @@
 //! Describes items defined or visible (ie, imported) in a certain scope.
 //! This is shared between modules and blocks.
 
+use std::collections::hash_map::Entry;
+
 use hir_expand::name::Name;
 use once_cell::sync::Lazy;
 use ra_db::CrateId;
@@ -27,9 +29,15 @@ pub struct PerNsGlobImports {
 
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct ItemScope {
-    visible: FxHashMap<Name, PerNs>,
+    types: FxHashMap<Name, (ModuleDefId, Visibility)>,
+    values: FxHashMap<Name, (ModuleDefId, Visibility)>,
+    macros: FxHashMap<Name, (MacroDefId, Visibility)>,
+    unresolved: FxHashSet<Name>,
+
     defs: Vec<ModuleDefId>,
     impls: Vec<ImplId>,
+    /// Traits imported via `use Trait as _;`.
+    unnamed_trait_imports: FxHashMap<TraitId, Visibility>,
     /// Macros visible in current module in legacy textual scope
     ///
     /// For macros invoked by an unqualified identifier like `bar!()`, `legacy_macros` will be searched in first.
@@ -65,14 +73,16 @@ pub(crate) enum BuiltinShadowMode {
 /// Other methods will only resolve values, types and module scoped macros only.
 impl ItemScope {
     pub fn entries<'a>(&'a self) -> impl Iterator<Item = (&'a Name, PerNs)> + 'a {
-        //FIXME: shadowing
-        self.visible.iter().map(|(n, def)| (n, *def))
-    }
-
-    pub fn entries_without_primitives<'a>(
-        &'a self,
-    ) -> impl Iterator<Item = (&'a Name, PerNs)> + 'a {
-        self.visible.iter().map(|(n, def)| (n, *def))
+        // FIXME: shadowing
+        let keys: FxHashSet<_> = self
+            .types
+            .keys()
+            .chain(self.values.keys())
+            .chain(self.macros.keys())
+            .chain(self.unresolved.iter())
+            .collect();
+
+        keys.into_iter().map(move |name| (name, self.get(name)))
     }
 
     pub fn declarations(&self) -> impl Iterator<Item = ModuleDefId> + '_ {
@@ -91,7 +101,7 @@ impl ItemScope {
 
     /// Iterate over all module scoped macros
     pub(crate) fn macros<'a>(&'a self) -> impl Iterator<Item = (&'a Name, MacroDefId)> + 'a {
-        self.visible.iter().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
+        self.entries().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
     }
 
     /// Iterate over all legacy textual scoped macros visible at the end of the module
@@ -101,12 +111,16 @@ impl ItemScope {
 
     /// Get a name from current module scope, legacy macros are not included
     pub(crate) fn get(&self, name: &Name) -> PerNs {
-        self.visible.get(name).copied().unwrap_or_else(PerNs::none)
+        PerNs {
+            types: self.types.get(name).copied(),
+            values: self.values.get(name).copied(),
+            macros: self.macros.get(name).copied(),
+        }
     }
 
     pub(crate) fn name_of(&self, item: ItemInNs) -> Option<(&Name, Visibility)> {
-        for (name, per_ns) in &self.visible {
-            if let Some(vis) = item.match_with(*per_ns) {
+        for (name, per_ns) in self.entries() {
+            if let Some(vis) = item.match_with(per_ns) {
                 return Some((name, vis));
             }
         }
@@ -114,10 +128,13 @@ impl ItemScope {
     }
 
     pub(crate) fn traits<'a>(&'a self) -> impl Iterator<Item = TraitId> + 'a {
-        self.visible.values().filter_map(|def| match def.take_types() {
-            Some(ModuleDefId::TraitId(t)) => Some(t),
-            _ => None,
-        })
+        self.types
+            .values()
+            .filter_map(|(def, _)| match def {
+                ModuleDefId::TraitId(t) => Some(*t),
+                _ => None,
+            })
+            .chain(self.unnamed_trait_imports.keys().copied())
     }
 
     pub(crate) fn define_def(&mut self, def: ModuleDefId) {
@@ -136,23 +153,40 @@ impl ItemScope {
         self.legacy_macros.insert(name, mac);
     }
 
+    pub(crate) fn unnamed_trait_vis(&self, tr: TraitId) -> Option<Visibility> {
+        self.unnamed_trait_imports.get(&tr).copied()
+    }
+
+    pub(crate) fn push_unnamed_trait(&mut self, tr: TraitId, vis: Visibility) {
+        self.unnamed_trait_imports.insert(tr, vis);
+    }
+
     pub(crate) fn push_res(&mut self, name: Name, def: PerNs) -> bool {
         let mut changed = false;
-        let existing = self.visible.entry(name).or_default();
 
-        if existing.types.is_none() && def.types.is_some() {
-            existing.types = def.types;
-            changed = true;
+        if let Some(types) = def.types {
+            self.types.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                types
+            });
         }
-
-        if existing.values.is_none() && def.values.is_some() {
-            existing.values = def.values;
-            changed = true;
+        if let Some(values) = def.values {
+            self.values.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                values
+            });
+        }
+        if let Some(macros) = def.macros {
+            self.macros.entry(name.clone()).or_insert_with(|| {
+                changed = true;
+                macros
+            });
         }
 
-        if existing.macros.is_none() && def.macros.is_some() {
-            existing.macros = def.macros;
-            changed = true;
+        if def.is_none() {
+            if self.unresolved.insert(name) {
+                changed = true;
+            }
         }
 
         changed
@@ -166,17 +200,17 @@ impl ItemScope {
         def_import_type: ImportType,
     ) -> bool {
         let mut changed = false;
-        let existing = self.visible.entry(lookup.1.clone()).or_default();
 
         macro_rules! check_changed {
             (
                 $changed:ident,
-                ( $existing:ident / $def:ident ) . $field:ident,
+                ( $this:ident / $def:ident ) . $field:ident,
                 $glob_imports:ident [ $lookup:ident ],
                 $def_import_type:ident
-            ) => {
-                match ($existing.$field, $def.$field) {
-                    (None, Some(_)) => {
+            ) => {{
+                let existing = $this.$field.entry($lookup.1.clone());
+                match (existing, $def.$field) {
+                    (Entry::Vacant(entry), Some(_)) => {
                         match $def_import_type {
                             ImportType::Glob => {
                                 $glob_imports.$field.insert($lookup.clone());
@@ -186,32 +220,46 @@ impl ItemScope {
                             }
                         }
 
-                        $existing.$field = $def.$field;
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
                         $changed = true;
                     }
-                    (Some(_), Some(_))
+                    (Entry::Occupied(mut entry), Some(_))
                         if $glob_imports.$field.contains(&$lookup)
                             && matches!($def_import_type, ImportType::Named) =>
                     {
                         mark::hit!(import_shadowed);
                         $glob_imports.$field.remove(&$lookup);
-                        $existing.$field = $def.$field;
+                        if let Some(fld) = $def.$field {
+                            entry.insert(fld);
+                        }
                         $changed = true;
                     }
                     _ => {}
                 }
-            };
+            }};
         }
 
-        check_changed!(changed, (existing / def).types, glob_imports[lookup], def_import_type);
-        check_changed!(changed, (existing / def).values, glob_imports[lookup], def_import_type);
-        check_changed!(changed, (existing / def).macros, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).types, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).values, glob_imports[lookup], def_import_type);
+        check_changed!(changed, (self / def).macros, glob_imports[lookup], def_import_type);
+
+        if def.is_none() {
+            if self.unresolved.insert(lookup.1) {
+                changed = true;
+            }
+        }
 
         changed
     }
 
-    pub(crate) fn resolutions<'a>(&'a self) -> impl Iterator<Item = (Name, PerNs)> + 'a {
-        self.visible.iter().map(|(name, res)| (name.clone(), *res))
+    pub(crate) fn resolutions<'a>(&'a self) -> impl Iterator<Item = (Option<Name>, PerNs)> + 'a {
+        self.entries().map(|(name, res)| (Some(name.clone()), res)).chain(
+            self.unnamed_trait_imports
+                .iter()
+                .map(|(tr, vis)| (None, PerNs::types(ModuleDefId::TraitId(*tr), *vis))),
+        )
     }
 
     pub(crate) fn collect_legacy_macros(&self) -> FxHashMap<Name, MacroDefId> {
diff --git a/crates/ra_hir_def/src/item_tree.rs b/crates/ra_hir_def/src/item_tree.rs
index 3e603bd55..a67e75dac 100644
--- a/crates/ra_hir_def/src/item_tree.rs
+++ b/crates/ra_hir_def/src/item_tree.rs
@@ -13,7 +13,7 @@ use std::{
     sync::Arc,
 };
 
-use ast::{AstNode, AttrsOwner, NameOwner, StructKind, TypeAscriptionOwner};
+use ast::{AstNode, AttrsOwner, NameOwner, StructKind};
 use either::Either;
 use hir_expand::{
     ast_id_map::FileAstId,
@@ -70,7 +70,7 @@ impl GenericParamsId {
 pub struct ItemTree {
     top_level: SmallVec<[ModItem; 1]>,
     attrs: FxHashMap<AttrOwner, Attrs>,
-    inner_items: FxHashMap<FileAstId<ast::ModuleItem>, SmallVec<[ModItem; 1]>>,
+    inner_items: FxHashMap<FileAstId<ast::Item>, SmallVec<[ModItem; 1]>>,
 
     data: Option<Box<ItemTreeData>>,
 }
@@ -187,7 +187,7 @@ impl ItemTree {
     ///
     /// Most AST items are lowered to a single `ModItem`, but some (eg. `use` items) may be lowered
     /// to multiple items in the `ItemTree`.
-    pub fn inner_items(&self, ast: FileAstId<ast::ModuleItem>) -> &[ModItem] {
+    pub fn inner_items(&self, ast: FileAstId<ast::Item>) -> &[ModItem] {
         &self.inner_items[&ast]
     }
 
@@ -310,7 +310,7 @@ from_attrs!(ModItem(ModItem), Variant(Idx<Variant>), Field(Idx<Field>));
 
 /// Trait implemented by all item nodes in the item tree.
 pub trait ItemTreeNode: Clone {
-    type Source: AstNode + Into<ast::ModuleItem>;
+    type Source: AstNode + Into<ast::Item>;
 
     fn ast_id(&self) -> FileAstId<Self::Source>;
 
@@ -411,17 +411,17 @@ macro_rules! mod_items {
 }
 
 mod_items! {
-    Import in imports -> ast::UseItem,
-    ExternCrate in extern_crates -> ast::ExternCrateItem,
-    Function in functions -> ast::FnDef,
-    Struct in structs -> ast::StructDef,
-    Union in unions -> ast::UnionDef,
-    Enum in enums -> ast::EnumDef,
-    Const in consts -> ast::ConstDef,
-    Static in statics -> ast::StaticDef,
-    Trait in traits -> ast::TraitDef,
-    Impl in impls -> ast::ImplDef,
-    TypeAlias in type_aliases -> ast::TypeAliasDef,
+    Import in imports -> ast::Use,
+    ExternCrate in extern_crates -> ast::ExternCrate,
+    Function in functions -> ast::Fn,
+    Struct in structs -> ast::Struct,
+    Union in unions -> ast::Union,
+    Enum in enums -> ast::Enum,
+    Const in consts -> ast::Const,
+    Static in statics -> ast::Static,
+    Trait in traits -> ast::Trait,
+    Impl in impls -> ast::Impl,
+    TypeAlias in type_aliases -> ast::TypeAlias,
     Mod in mods -> ast::Module,
     MacroCall in macro_calls -> ast::MacroCall,
 }
@@ -482,7 +482,7 @@ pub struct Import {
     pub is_prelude: bool,
     /// AST ID of the `use` or `extern crate` item this import was derived from. Note that many
     /// `Import`s can map to the same `use` item.
-    pub ast_id: FileAstId<ast::UseItem>,
+    pub ast_id: FileAstId<ast::Use>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -492,7 +492,7 @@ pub struct ExternCrate {
     pub visibility: RawVisibilityId,
     /// Whether this is a `#[macro_use] extern crate ...`.
     pub is_macro_use: bool,
-    pub ast_id: FileAstId<ast::ExternCrateItem>,
+    pub ast_id: FileAstId<ast::ExternCrate>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -503,8 +503,9 @@ pub struct Function {
     pub has_self_param: bool,
     pub is_unsafe: bool,
     pub params: Box<[TypeRef]>,
+    pub is_varargs: bool,
     pub ret_type: TypeRef,
-    pub ast_id: FileAstId<ast::FnDef>,
+    pub ast_id: FileAstId<ast::Fn>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -513,7 +514,7 @@ pub struct Struct {
     pub visibility: RawVisibilityId,
     pub generic_params: GenericParamsId,
     pub fields: Fields,
-    pub ast_id: FileAstId<ast::StructDef>,
+    pub ast_id: FileAstId<ast::Struct>,
     pub kind: StructDefKind,
 }
 
@@ -533,7 +534,7 @@ pub struct Union {
     pub visibility: RawVisibilityId,
     pub generic_params: GenericParamsId,
     pub fields: Fields,
-    pub ast_id: FileAstId<ast::UnionDef>,
+    pub ast_id: FileAstId<ast::Union>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -542,7 +543,7 @@ pub struct Enum {
     pub visibility: RawVisibilityId,
     pub generic_params: GenericParamsId,
     pub variants: IdRange<Variant>,
-    pub ast_id: FileAstId<ast::EnumDef>,
+    pub ast_id: FileAstId<ast::Enum>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -551,7 +552,7 @@ pub struct Const {
     pub name: Option<Name>,
     pub visibility: RawVisibilityId,
     pub type_ref: TypeRef,
-    pub ast_id: FileAstId<ast::ConstDef>,
+    pub ast_id: FileAstId<ast::Const>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -560,7 +561,7 @@ pub struct Static {
     pub visibility: RawVisibilityId,
     pub mutable: bool,
     pub type_ref: TypeRef,
-    pub ast_id: FileAstId<ast::StaticDef>,
+    pub ast_id: FileAstId<ast::Static>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -570,7 +571,7 @@ pub struct Trait {
     pub generic_params: GenericParamsId,
     pub auto: bool,
     pub items: Box<[AssocItem]>,
-    pub ast_id: FileAstId<ast::TraitDef>,
+    pub ast_id: FileAstId<ast::Trait>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
@@ -580,7 +581,7 @@ pub struct Impl {
     pub target_type: TypeRef,
     pub is_negative: bool,
     pub items: Box<[AssocItem]>,
-    pub ast_id: FileAstId<ast::ImplDef>,
+    pub ast_id: FileAstId<ast::Impl>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -591,7 +592,7 @@ pub struct TypeAlias {
     pub bounds: Box<[TypeBound]>,
     pub generic_params: GenericParamsId,
     pub type_ref: Option<TypeRef>,
-    pub ast_id: FileAstId<ast::TypeAliasDef>,
+    pub ast_id: FileAstId<ast::TypeAlias>,
 }
 
 #[derive(Debug, Clone, Eq, PartialEq)]
diff --git a/crates/ra_hir_def/src/item_tree/lower.rs b/crates/ra_hir_def/src/item_tree/lower.rs
index 5149dd141..feb31579e 100644
--- a/crates/ra_hir_def/src/item_tree/lower.rs
+++ b/crates/ra_hir_def/src/item_tree/lower.rs
@@ -1,10 +1,7 @@
 //! AST -> `ItemTree` lowering code.
 
-use super::*;
-use crate::{
-    attr::Attrs,
-    generics::{GenericParams, TypeParamData, TypeParamProvenance},
-};
+use std::{collections::hash_map::Entry, mem, sync::Arc};
+
 use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, HirFileId};
 use ra_arena::map::ArenaMap;
 use ra_syntax::{
@@ -12,7 +9,13 @@ use ra_syntax::{
     SyntaxNode,
 };
 use smallvec::SmallVec;
-use std::{collections::hash_map::Entry, mem, sync::Arc};
+
+use crate::{
+    attr::Attrs,
+    generics::{GenericParams, TypeParamData, TypeParamProvenance},
+};
+
+use super::*;
 
 fn id<N: ItemTreeNode>(index: Idx<N>) -> FileItemTreeId<N> {
     FileItemTreeId { index, _p: PhantomData }
@@ -70,19 +73,19 @@ impl Ctx {
         self.tree.data_mut()
     }
 
-    fn lower_mod_item(&mut self, item: &ast::ModuleItem, inner: bool) -> Option<ModItems> {
+    fn lower_mod_item(&mut self, item: &ast::Item, inner: bool) -> Option<ModItems> {
         assert!(inner || self.inner_items.is_empty());
 
         // Collect inner items for 1-to-1-lowered items.
         match item {
-            ast::ModuleItem::StructDef(_)
-            | ast::ModuleItem::UnionDef(_)
-            | ast::ModuleItem::EnumDef(_)
-            | ast::ModuleItem::FnDef(_)
-            | ast::ModuleItem::TypeAliasDef(_)
-            | ast::ModuleItem::ConstDef(_)
-            | ast::ModuleItem::StaticDef(_)
-            | ast::ModuleItem::MacroCall(_) => {
+            ast::Item::Struct(_)
+            | ast::Item::Union(_)
+            | ast::Item::Enum(_)
+            | ast::Item::Fn(_)
+            | ast::Item::TypeAlias(_)
+            | ast::Item::Const(_)
+            | ast::Item::Static(_)
+            | ast::Item::MacroCall(_) => {
                 // Skip this if we're already collecting inner items. We'll descend into all nodes
                 // already.
                 if !inner {
@@ -92,34 +95,30 @@ impl Ctx {
 
             // These are handled in their respective `lower_X` method (since we can't just blindly
             // walk them).
-            ast::ModuleItem::TraitDef(_)
-            | ast::ModuleItem::ImplDef(_)
-            | ast::ModuleItem::ExternBlock(_) => {}
+            ast::Item::Trait(_) | ast::Item::Impl(_) | ast::Item::ExternBlock(_) => {}
 
             // These don't have inner items.
-            ast::ModuleItem::Module(_)
-            | ast::ModuleItem::ExternCrateItem(_)
-            | ast::ModuleItem::UseItem(_) => {}
+            ast::Item::Module(_) | ast::Item::ExternCrate(_) | ast::Item::Use(_) => {}
         };
 
         let attrs = Attrs::new(item, &self.hygiene);
         let items = match item {
-            ast::ModuleItem::StructDef(ast) => self.lower_struct(ast).map(Into::into),
-            ast::ModuleItem::UnionDef(ast) => self.lower_union(ast).map(Into::into),
-            ast::ModuleItem::EnumDef(ast) => self.lower_enum(ast).map(Into::into),
-            ast::ModuleItem::FnDef(ast) => self.lower_function(ast).map(Into::into),
-            ast::ModuleItem::TypeAliasDef(ast) => self.lower_type_alias(ast).map(Into::into),
-            ast::ModuleItem::StaticDef(ast) => self.lower_static(ast).map(Into::into),
-            ast::ModuleItem::ConstDef(ast) => Some(self.lower_const(ast).into()),
-            ast::ModuleItem::Module(ast) => self.lower_module(ast).map(Into::into),
-            ast::ModuleItem::TraitDef(ast) => self.lower_trait(ast).map(Into::into),
-            ast::ModuleItem::ImplDef(ast) => self.lower_impl(ast).map(Into::into),
-            ast::ModuleItem::UseItem(ast) => Some(ModItems(
+            ast::Item::Struct(ast) => self.lower_struct(ast).map(Into::into),
+            ast::Item::Union(ast) => self.lower_union(ast).map(Into::into),
+            ast::Item::Enum(ast) => self.lower_enum(ast).map(Into::into),
+            ast::Item::Fn(ast) => self.lower_function(ast).map(Into::into),
+            ast::Item::TypeAlias(ast) => self.lower_type_alias(ast).map(Into::into),
+            ast::Item::Static(ast) => self.lower_static(ast).map(Into::into),
+            ast::Item::Const(ast) => Some(self.lower_const(ast).into()),
+            ast::Item::Module(ast) => self.lower_module(ast).map(Into::into),
+            ast::Item::Trait(ast) => self.lower_trait(ast).map(Into::into),
+            ast::Item::Impl(ast) => self.lower_impl(ast).map(Into::into),
+            ast::Item::Use(ast) => Some(ModItems(
                 self.lower_use(ast).into_iter().map(Into::into).collect::<SmallVec<_>>(),
             )),
-            ast::ModuleItem::ExternCrateItem(ast) => self.lower_extern_crate(ast).map(Into::into),
-            ast::ModuleItem::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
-            ast::ModuleItem::ExternBlock(ast) => {
+            ast::Item::ExternCrate(ast) => self.lower_extern_crate(ast).map(Into::into),
+            ast::Item::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
+            ast::Item::ExternBlock(ast) => {
                 Some(ModItems(self.lower_extern_block(ast).into_iter().collect::<SmallVec<_>>()))
             }
         };
@@ -147,27 +146,26 @@ impl Ctx {
     fn collect_inner_items(&mut self, container: &SyntaxNode) {
         let forced_vis = self.forced_visibility.take();
         let mut inner_items = mem::take(&mut self.tree.inner_items);
-        inner_items.extend(
-            container.descendants().skip(1).filter_map(ast::ModuleItem::cast).filter_map(|item| {
+        inner_items.extend(container.descendants().skip(1).filter_map(ast::Item::cast).filter_map(
+            |item| {
                 let ast_id = self.source_ast_id_map.ast_id(&item);
                 Some((ast_id, self.lower_mod_item(&item, true)?.0))
-            }),
-        );
+            },
+        ));
         self.tree.inner_items = inner_items;
         self.forced_visibility = forced_vis;
     }
 
-    fn lower_assoc_item(&mut self, item: &ast::ModuleItem) -> Option<AssocItem> {
+    fn lower_assoc_item(&mut self, item: &ast::AssocItem) -> Option<AssocItem> {
         match item {
-            ast::ModuleItem::FnDef(ast) => self.lower_function(ast).map(Into::into),
-            ast::ModuleItem::TypeAliasDef(ast) => self.lower_type_alias(ast).map(Into::into),
-            ast::ModuleItem::ConstDef(ast) => Some(self.lower_const(ast).into()),
-            ast::ModuleItem::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
-            _ => None,
+            ast::AssocItem::Fn(ast) => self.lower_function(ast).map(Into::into),
+            ast::AssocItem::TypeAlias(ast) => self.lower_type_alias(ast).map(Into::into),
+            ast::AssocItem::Const(ast) => Some(self.lower_const(ast).into()),
+            ast::AssocItem::MacroCall(ast) => self.lower_macro_call(ast).map(Into::into),
         }
     }
 
-    fn lower_struct(&mut self, strukt: &ast::StructDef) -> Option<FileItemTreeId<Struct>> {
+    fn lower_struct(&mut self, strukt: &ast::Struct) -> Option<FileItemTreeId<Struct>> {
         let visibility = self.lower_visibility(strukt);
         let name = strukt.name()?.as_name();
         let generic_params = self.lower_generic_params(GenericsOwner::Struct, strukt);
@@ -196,7 +194,7 @@ impl Ctx {
         }
     }
 
-    fn lower_record_fields(&mut self, fields: &ast::RecordFieldDefList) -> IdRange<Field> {
+    fn lower_record_fields(&mut self, fields: &ast::RecordFieldList) -> IdRange<Field> {
         let start = self.next_field_idx();
         for field in fields.fields() {
             if let Some(data) = self.lower_record_field(&field) {
@@ -208,42 +206,39 @@ impl Ctx {
         IdRange::new(start..end)
     }
 
-    fn lower_record_field(&mut self, field: &ast::RecordFieldDef) -> Option<Field> {
+    fn lower_record_field(&mut self, field: &ast::RecordField) -> Option<Field> {
         let name = field.name()?.as_name();
         let visibility = self.lower_visibility(field);
-        let type_ref = self.lower_type_ref(&field.ascribed_type()?);
+        let type_ref = self.lower_type_ref_opt(field.ty());
         let res = Field { name, type_ref, visibility };
         Some(res)
     }
 
-    fn lower_tuple_fields(&mut self, fields: &ast::TupleFieldDefList) -> IdRange<Field> {
+    fn lower_tuple_fields(&mut self, fields: &ast::TupleFieldList) -> IdRange<Field> {
         let start = self.next_field_idx();
         for (i, field) in fields.fields().enumerate() {
-            if let Some(data) = self.lower_tuple_field(i, &field) {
-                let idx = self.data().fields.alloc(data);
-                self.add_attrs(idx.into(), Attrs::new(&field, &self.hygiene));
-            }
+            let data = self.lower_tuple_field(i, &field);
+            let idx = self.data().fields.alloc(data);
+            self.add_attrs(idx.into(), Attrs::new(&field, &self.hygiene));
         }
         let end = self.next_field_idx();
         IdRange::new(start..end)
     }
 
-    fn lower_tuple_field(&mut self, idx: usize, field: &ast::TupleFieldDef) -> Option<Field> {
+    fn lower_tuple_field(&mut self, idx: usize, field: &ast::TupleField) -> Field {
         let name = Name::new_tuple_field(idx);
         let visibility = self.lower_visibility(field);
-        let type_ref = self.lower_type_ref(&field.type_ref()?);
+        let type_ref = self.lower_type_ref_opt(field.ty());
         let res = Field { name, type_ref, visibility };
-        Some(res)
+        res
     }
 
-    fn lower_union(&mut self, union: &ast::UnionDef) -> Option<FileItemTreeId<Union>> {
+    fn lower_union(&mut self, union: &ast::Union) -> Option<FileItemTreeId<Union>> {
         let visibility = self.lower_visibility(union);
         let name = union.name()?.as_name();
         let generic_params = self.lower_generic_params(GenericsOwner::Union, union);
-        let fields = match union.record_field_def_list() {
-            Some(record_field_def_list) => {
-                self.lower_fields(&StructKind::Record(record_field_def_list))
-            }
+        let fields = match union.record_field_list() {
+            Some(record_field_list) => self.lower_fields(&StructKind::Record(record_field_list)),
             None => Fields::Record(IdRange::new(self.next_field_idx()..self.next_field_idx())),
         };
         let ast_id = self.source_ast_id_map.ast_id(union);
@@ -251,7 +246,7 @@ impl Ctx {
         Some(id(self.data().unions.alloc(res)))
     }
 
-    fn lower_enum(&mut self, enum_: &ast::EnumDef) -> Option<FileItemTreeId<Enum>> {
+    fn lower_enum(&mut self, enum_: &ast::Enum) -> Option<FileItemTreeId<Enum>> {
         let visibility = self.lower_visibility(enum_);
         let name = enum_.name()?.as_name();
         let generic_params = self.lower_generic_params(GenericsOwner::Enum, enum_);
@@ -264,7 +259,7 @@ impl Ctx {
         Some(id(self.data().enums.alloc(res)))
     }
 
-    fn lower_variants(&mut self, variants: &ast::EnumVariantList) -> IdRange<Variant> {
+    fn lower_variants(&mut self, variants: &ast::VariantList) -> IdRange<Variant> {
         let start = self.next_variant_idx();
         for variant in variants.variants() {
             if let Some(data) = self.lower_variant(&variant) {
@@ -276,14 +271,14 @@ impl Ctx {
         IdRange::new(start..end)
     }
 
-    fn lower_variant(&mut self, variant: &ast::EnumVariant) -> Option<Variant> {
+    fn lower_variant(&mut self, variant: &ast::Variant) -> Option<Variant> {
         let name = variant.name()?.as_name();
         let fields = self.lower_fields(&variant.kind());
         let res = Variant { name, fields };
         Some(res)
     }
 
-    fn lower_function(&mut self, func: &ast::FnDef) -> Option<FileItemTreeId<Function>> {
+    fn lower_function(&mut self, func: &ast::Fn) -> Option<FileItemTreeId<Function>> {
         let visibility = self.lower_visibility(func);
         let name = func.name()?.as_name();
 
@@ -291,7 +286,7 @@ impl Ctx {
         let mut has_self_param = false;
         if let Some(param_list) = func.param_list() {
             if let Some(self_param) = param_list.self_param() {
-                let self_type = match self_param.ascribed_type() {
+                let self_type = match self_param.ty() {
                     Some(type_ref) => TypeRef::from_ast(&self.body_ctx, type_ref),
                     None => {
                         let self_type = TypeRef::Path(name![Self].into());
@@ -310,11 +305,19 @@ impl Ctx {
                 has_self_param = true;
             }
             for param in param_list.params() {
-                let type_ref = TypeRef::from_ast_opt(&self.body_ctx, param.ascribed_type());
+                let type_ref = TypeRef::from_ast_opt(&self.body_ctx, param.ty());
                 params.push(type_ref);
             }
         }
-        let ret_type = match func.ret_type().and_then(|rt| rt.type_ref()) {
+
+        let mut is_varargs = false;
+        if let Some(params) = func.param_list() {
+            if let Some(last) = params.params().last() {
+                is_varargs = last.dotdotdot_token().is_some();
+            }
+        }
+
+        let ret_type = match func.ret_type().and_then(|rt| rt.ty()) {
             Some(type_ref) => TypeRef::from_ast(&self.body_ctx, type_ref),
             _ => TypeRef::unit(),
         };
@@ -335,6 +338,7 @@ impl Ctx {
             has_self_param,
             is_unsafe: func.unsafe_token().is_some(),
             params: params.into_boxed_slice(),
+            is_varargs,
             ret_type,
             ast_id,
         };
@@ -345,10 +349,10 @@ impl Ctx {
 
     fn lower_type_alias(
         &mut self,
-        type_alias: &ast::TypeAliasDef,
+        type_alias: &ast::TypeAlias,
     ) -> Option<FileItemTreeId<TypeAlias>> {
         let name = type_alias.name()?.as_name();
-        let type_ref = type_alias.type_ref().map(|it| self.lower_type_ref(&it));
+        let type_ref = type_alias.ty().map(|it| self.lower_type_ref(&it));
         let visibility = self.lower_visibility(type_alias);
         let bounds = self.lower_type_bounds(type_alias);
         let generic_params = self.lower_generic_params(GenericsOwner::TypeAlias, type_alias);
@@ -364,9 +368,9 @@ impl Ctx {
         Some(id(self.data().type_aliases.alloc(res)))
     }
 
-    fn lower_static(&mut self, static_: &ast::StaticDef) -> Option<FileItemTreeId<Static>> {
+    fn lower_static(&mut self, static_: &ast::Static) -> Option<FileItemTreeId<Static>> {
         let name = static_.name()?.as_name();
-        let type_ref = self.lower_type_ref_opt(static_.ascribed_type());
+        let type_ref = self.lower_type_ref_opt(static_.ty());
         let visibility = self.lower_visibility(static_);
         let mutable = static_.mut_token().is_some();
         let ast_id = self.source_ast_id_map.ast_id(static_);
@@ -374,9 +378,9 @@ impl Ctx {
         Some(id(self.data().statics.alloc(res)))
     }
 
-    fn lower_const(&mut self, konst: &ast::ConstDef) -> FileItemTreeId<Const> {
+    fn lower_const(&mut self, konst: &ast::Const) -> FileItemTreeId<Const> {
         let name = konst.name().map(|it| it.as_name());
-        let type_ref = self.lower_type_ref_opt(konst.ascribed_type());
+        let type_ref = self.lower_type_ref_opt(konst.ty());
         let visibility = self.lower_visibility(konst);
         let ast_id = self.source_ast_id_map.ast_id(konst);
         let res = Const { name, visibility, type_ref, ast_id };
@@ -409,15 +413,15 @@ impl Ctx {
         Some(id(self.data().mods.alloc(res)))
     }
 
-    fn lower_trait(&mut self, trait_def: &ast::TraitDef) -> Option<FileItemTreeId<Trait>> {
+    fn lower_trait(&mut self, trait_def: &ast::Trait) -> Option<FileItemTreeId<Trait>> {
         let name = trait_def.name()?.as_name();
         let visibility = self.lower_visibility(trait_def);
         let generic_params =
             self.lower_generic_params_and_inner_items(GenericsOwner::Trait(trait_def), trait_def);
         let auto = trait_def.auto_token().is_some();
-        let items = trait_def.item_list().map(|list| {
+        let items = trait_def.assoc_item_list().map(|list| {
             self.with_inherited_visibility(visibility, |this| {
-                list.items()
+                list.assoc_items()
                     .filter_map(|item| {
                         let attrs = Attrs::new(&item, &this.hygiene);
                         this.collect_inner_items(item.syntax());
@@ -441,7 +445,7 @@ impl Ctx {
         Some(id(self.data().traits.alloc(res)))
     }
 
-    fn lower_impl(&mut self, impl_def: &ast::ImplDef) -> Option<FileItemTreeId<Impl>> {
+    fn lower_impl(&mut self, impl_def: &ast::Impl) -> Option<FileItemTreeId<Impl>> {
         let generic_params =
             self.lower_generic_params_and_inner_items(GenericsOwner::Impl, impl_def);
         let target_trait = impl_def.target_trait().map(|tr| self.lower_type_ref(&tr));
@@ -450,8 +454,9 @@ impl Ctx {
 
         // We cannot use `assoc_items()` here as that does not include macro calls.
         let items = impl_def
-            .item_list()?
-            .items()
+            .assoc_item_list()
+            .into_iter()
+            .flat_map(|it| it.assoc_items())
             .filter_map(|item| {
                 self.collect_inner_items(item.syntax());
                 let assoc = self.lower_assoc_item(&item)?;
@@ -465,7 +470,7 @@ impl Ctx {
         Some(id(self.data().impls.alloc(res)))
     }
 
-    fn lower_use(&mut self, use_item: &ast::UseItem) -> Vec<FileItemTreeId<Import>> {
+    fn lower_use(&mut self, use_item: &ast::Use) -> Vec<FileItemTreeId<Import>> {
         // FIXME: cfg_attr
         let is_prelude = use_item.has_atom_attr("prelude_import");
         let visibility = self.lower_visibility(use_item);
@@ -494,10 +499,10 @@ impl Ctx {
 
     fn lower_extern_crate(
         &mut self,
-        extern_crate: &ast::ExternCrateItem,
+        extern_crate: &ast::ExternCrate,
     ) -> Option<FileItemTreeId<ExternCrate>> {
         let path = ModPath::from_name_ref(&extern_crate.name_ref()?);
-        let alias = extern_crate.alias().map(|a| {
+        let alias = extern_crate.rename().map(|a| {
             a.name().map(|it| it.as_name()).map_or(ImportAlias::Underscore, ImportAlias::Alias)
         });
         let visibility = self.lower_visibility(extern_crate);
@@ -543,14 +548,16 @@ impl Ctx {
                     self.collect_inner_items(item.syntax());
                     let attrs = Attrs::new(&item, &self.hygiene);
                     let id: ModItem = match item {
-                        ast::ExternItem::FnDef(ast) => {
+                        ast::ExternItem::Fn(ast) => {
                             let func = self.lower_function(&ast)?;
+                            self.data().functions[func.index].is_unsafe = true;
                             func.into()
                         }
-                        ast::ExternItem::StaticDef(ast) => {
+                        ast::ExternItem::Static(ast) => {
                             let statik = self.lower_static(&ast)?;
                             statik.into()
                         }
+                        ast::ExternItem::MacroCall(_) => return None,
                     };
                     self.add_attrs(id.into(), attrs);
                     Some(id)
@@ -563,10 +570,10 @@ impl Ctx {
     fn lower_generic_params_and_inner_items(
         &mut self,
         owner: GenericsOwner<'_>,
-        node: &impl ast::TypeParamsOwner,
+        node: &impl ast::GenericParamsOwner,
     ) -> GenericParamsId {
         // Generics are part of item headers and may contain inner items we need to collect.
-        if let Some(params) = node.type_param_list() {
+        if let Some(params) = node.generic_param_list() {
             self.collect_inner_items(params.syntax());
         }
         if let Some(clause) = node.where_clause() {
@@ -579,7 +586,7 @@ impl Ctx {
     fn lower_generic_params(
         &mut self,
         owner: GenericsOwner<'_>,
-        node: &impl ast::TypeParamsOwner,
+        node: &impl ast::GenericParamsOwner,
     ) -> GenericParamsId {
         let mut sm = &mut ArenaMap::default();
         let mut generics = GenericParams::default();
@@ -692,7 +699,7 @@ enum GenericsOwner<'a> {
     Enum,
     Union,
     /// The `TraitDef` is needed to fill the source map for the implicit `Self` parameter.
-    Trait(&'a ast::TraitDef),
+    Trait(&'a ast::Trait),
     TypeAlias,
     Impl,
 }
diff --git a/crates/ra_hir_def/src/item_tree/tests.rs b/crates/ra_hir_def/src/item_tree/tests.rs
index 08559fb92..a81497fa8 100644
--- a/crates/ra_hir_def/src/item_tree/tests.rs
+++ b/crates/ra_hir_def/src/item_tree/tests.rs
@@ -1,13 +1,15 @@
-use super::{ItemTree, ModItem, ModKind};
-use crate::{db::DefDatabase, test_db::TestDB};
+use expect::{expect, Expect};
 use hir_expand::{db::AstDatabase, HirFileId, InFile};
-use insta::assert_snapshot;
 use ra_db::fixture::WithFixture;
 use ra_syntax::{ast, AstNode};
 use rustc_hash::FxHashSet;
 use std::sync::Arc;
 use stdx::format_to;
 
+use crate::{db::DefDatabase, test_db::TestDB};
+
+use super::{ItemTree, ModItem, ModKind};
+
 fn test_inner_items(ra_fixture: &str) {
     let (db, file_id) = TestDB::with_single_file(ra_fixture);
     let file_id = HirFileId::from(file_id);
@@ -19,7 +21,7 @@ fn test_inner_items(ra_fixture: &str) {
     let mut outer_items = FxHashSet::default();
     let mut worklist = tree.top_level_items().to_vec();
     while let Some(item) = worklist.pop() {
-        let node: ast::ModuleItem = match item {
+        let node: ast::Item = match item {
             ModItem::Import(it) => tree.source(&db, InFile::new(file_id, it)).into(),
             ModItem::ExternCrate(it) => tree.source(&db, InFile::new(file_id, it)).into(),
             ModItem::Function(it) => tree.source(&db, InFile::new(file_id, it)).into(),
@@ -51,7 +53,7 @@ fn test_inner_items(ra_fixture: &str) {
 
     // Now descend the root node and check that all `ast::ModuleItem`s are either recorded above, or
     // registered as inner items.
-    for item in root.descendants().skip(1).filter_map(ast::ModuleItem::cast) {
+    for item in root.descendants().skip(1).filter_map(ast::Item::cast) {
         if outer_items.contains(&item) {
             continue;
         }
@@ -162,9 +164,15 @@ fn fmt_mod_item(out: &mut String, tree: &ItemTree, item: ModItem) {
     }
 }
 
+fn check(ra_fixture: &str, expect: Expect) {
+    let actual = print_item_tree(ra_fixture);
+    expect.assert_eq(&actual);
+}
+
 #[test]
 fn smoke() {
-    assert_snapshot!(print_item_tree(r"
+    check(
+        r"
         #![attr]
 
         #[attr_on_use]
@@ -214,42 +222,44 @@ fn smoke() {
             #[union_fld]
             fld: u16,
         }
-    "), @r###"
-inner attrs: Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr"))] }, input: None }]) }
-
-top-level items:
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_on_use"))] }, input: None }]) }]
-Import { path: ModPath { kind: Plain, segments: [Name(Text("a"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_glob: false, is_prelude: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::UseItem>(0) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_on_use"))] }, input: None }]) }]
-Import { path: ModPath { kind: Plain, segments: [Name(Text("b"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_glob: true, is_prelude: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::UseItem>(0) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("ext_crate"))] }, input: None }]) }]
-ExternCrate { path: ModPath { kind: Plain, segments: [Name(Text("krate"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_macro_use: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ExternCrateItem>(1) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("on_trait"))] }, input: None }]) }]
-Trait { name: Name(Text("Tr")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(0), auto: false, items: [TypeAlias(Idx::<TypeAlias>(0)), Const(Idx::<Const>(0)), Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::TraitDef>(2) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_ty"))] }, input: None }]) }]
-> TypeAlias { name: Name(Text("AssocTy")), visibility: RawVisibilityId("pub(self)"), bounds: [Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Tr"))] }, generic_args: [Some(GenericArgs { args: [Type(Tuple([]))], has_self_type: false, bindings: [] })] })], generic_params: GenericParamsId(4294967295), type_ref: None, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::TypeAliasDef>(8) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_const"))] }, input: None }]) }]
-> Const { name: Some(Name(Text("CONST"))), visibility: RawVisibilityId("pub(self)"), type_ref: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("u8"))] }, generic_args: [None] }), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ConstDef>(9) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_method"))] }, input: None }]) }]
-> Function { name: Name(Text("method")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: true, is_unsafe: false, params: [Reference(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Self"))] }, generic_args: [None] }), Shared)], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(10) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_dfl_method"))] }, input: None }]) }]
-> Function { name: Name(Text("dfl_method")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: true, is_unsafe: false, params: [Reference(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Self"))] }, generic_args: [None] }), Mut)], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(11) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct0"))] }, input: None }]) }]
-Struct { name: Name(Text("Struct0")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(1), fields: Unit, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::StructDef>(3), kind: Unit }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct1"))] }, input: None }]) }]
-Struct { name: Name(Text("Struct1")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(2), fields: Tuple(IdRange::<ra_hir_def::item_tree::Field>(0..1)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::StructDef>(4), kind: Tuple }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct2"))] }, input: None }]) }]
-Struct { name: Name(Text("Struct2")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(3), fields: Record(IdRange::<ra_hir_def::item_tree::Field>(1..2)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::StructDef>(5), kind: Record }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("en"))] }, input: None }]) }]
-Enum { name: Name(Text("En")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), variants: IdRange::<ra_hir_def::item_tree::Variant>(0..1), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::EnumDef>(6) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("un"))] }, input: None }]) }]
-Union { name: Name(Text("Un")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), fields: Record(IdRange::<ra_hir_def::item_tree::Field>(3..4)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::UnionDef>(7) }
-    "###);
+    ",
+        expect![[r##"
+            inner attrs: Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr"))] }, input: None }]) }
+
+            top-level items:
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_on_use"))] }, input: None }]) }]
+            Import { path: ModPath { kind: Plain, segments: [Name(Text("a"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_glob: false, is_prelude: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Use>(0) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_on_use"))] }, input: None }]) }]
+            Import { path: ModPath { kind: Plain, segments: [Name(Text("b"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_glob: true, is_prelude: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Use>(0) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("ext_crate"))] }, input: None }]) }]
+            ExternCrate { path: ModPath { kind: Plain, segments: [Name(Text("krate"))] }, alias: None, visibility: RawVisibilityId("pub(self)"), is_macro_use: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ExternCrate>(1) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("on_trait"))] }, input: None }]) }]
+            Trait { name: Name(Text("Tr")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(0), auto: false, items: [TypeAlias(Idx::<TypeAlias>(0)), Const(Idx::<Const>(0)), Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Trait>(2) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_ty"))] }, input: None }]) }]
+            > TypeAlias { name: Name(Text("AssocTy")), visibility: RawVisibilityId("pub(self)"), bounds: [Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Tr"))] }, generic_args: [Some(GenericArgs { args: [Type(Tuple([]))], has_self_type: false, bindings: [] })] })], generic_params: GenericParamsId(4294967295), type_ref: None, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::TypeAlias>(8) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_const"))] }, input: None }]) }]
+            > Const { name: Some(Name(Text("CONST"))), visibility: RawVisibilityId("pub(self)"), type_ref: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("u8"))] }, generic_args: [None] }), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Const>(9) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_method"))] }, input: None }]) }]
+            > Function { name: Name(Text("method")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: true, is_unsafe: false, params: [Reference(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Self"))] }, generic_args: [None] }), Shared)], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(10) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("assoc_dfl_method"))] }, input: None }]) }]
+            > Function { name: Name(Text("dfl_method")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: true, is_unsafe: false, params: [Reference(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Self"))] }, generic_args: [None] }), Mut)], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(11) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct0"))] }, input: None }]) }]
+            Struct { name: Name(Text("Struct0")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(1), fields: Unit, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Struct>(3), kind: Unit }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct1"))] }, input: None }]) }]
+            Struct { name: Name(Text("Struct1")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(2), fields: Tuple(IdRange::<ra_hir_def::item_tree::Field>(0..1)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Struct>(4), kind: Tuple }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("struct2"))] }, input: None }]) }]
+            Struct { name: Name(Text("Struct2")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(3), fields: Record(IdRange::<ra_hir_def::item_tree::Field>(1..2)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Struct>(5), kind: Record }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("en"))] }, input: None }]) }]
+            Enum { name: Name(Text("En")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), variants: IdRange::<ra_hir_def::item_tree::Variant>(0..1), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Enum>(6) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("un"))] }, input: None }]) }]
+            Union { name: Name(Text("Un")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), fields: Record(IdRange::<ra_hir_def::item_tree::Field>(3..4)), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Union>(7) }
+        "##]],
+    );
 }
 
 #[test]
 fn simple_inner_items() {
-    let tree = print_item_tree(
+    check(
         r"
         impl<T:A> D for Response<T> {
             fn foo() {
@@ -260,26 +270,25 @@ fn simple_inner_items() {
             }
         }
     ",
-    );
+        expect![[r#"
+            inner attrs: Attrs { entries: None }
 
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
+            top-level items:
+            Impl { generic_params: GenericParamsId(0), target_trait: Some(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("D"))] }, generic_args: [None] })), target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Response"))] }, generic_args: [Some(GenericArgs { args: [Type(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("T"))] }, generic_args: [None] }))], has_self_type: false, bindings: [] })] }), is_negative: false, items: [Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Impl>(0) }
+            > Function { name: Name(Text("foo")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(1) }
 
-top-level items:
-Impl { generic_params: GenericParamsId(0), target_trait: Some(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("D"))] }, generic_args: [None] })), target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Response"))] }, generic_args: [Some(GenericArgs { args: [Type(Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("T"))] }, generic_args: [None] }))], has_self_type: false, bindings: [] })] }), is_negative: false, items: [Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ImplDef>(0) }
-> Function { name: Name(Text("foo")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(1) }
+            inner items:
 
-inner items:
+            for AST FileAstId::<ra_syntax::ast::generated::nodes::Item>(2):
+            Function { name: Name(Text("end")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(1), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(2) }
 
-for AST FileAstId::<ra_syntax::ast::generated::nodes::ModuleItem>(2):
-Function { name: Name(Text("end")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(1), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(2) }
-
-    "###);
+        "#]],
+    );
 }
 
 #[test]
 fn extern_attrs() {
-    let tree = print_item_tree(
+    check(
         r#"
         #[block_attr]
         extern "C" {
@@ -289,22 +298,21 @@ fn extern_attrs() {
             fn b() {}
         }
     "#,
+        expect![[r##"
+            inner attrs: Attrs { entries: None }
+
+            top-level items:
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }, Attr { path: ModPath { kind: Plain, segments: [Name(Text("block_attr"))] }, input: None }]) }]
+            Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: true, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(1) }
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }, Attr { path: ModPath { kind: Plain, segments: [Name(Text("block_attr"))] }, input: None }]) }]
+            Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: true, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(2) }
+        "##]],
     );
-
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
-
-top-level items:
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }, Attr { path: ModPath { kind: Plain, segments: [Name(Text("block_attr"))] }, input: None }]) }]
-Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(1) }
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }, Attr { path: ModPath { kind: Plain, segments: [Name(Text("block_attr"))] }, input: None }]) }]
-Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(2) }
-    "###);
 }
 
 #[test]
 fn trait_attrs() {
-    let tree = print_item_tree(
+    check(
         r#"
         #[trait_attr]
         trait Tr {
@@ -314,24 +322,23 @@ fn trait_attrs() {
             fn b() {}
         }
     "#,
+        expect![[r##"
+            inner attrs: Attrs { entries: None }
+
+            top-level items:
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("trait_attr"))] }, input: None }]) }]
+            Trait { name: Name(Text("Tr")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(0), auto: false, items: [Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Trait>(0) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }]) }]
+            > Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(1) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }]) }]
+            > Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(2) }
+        "##]],
     );
-
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
-
-top-level items:
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("trait_attr"))] }, input: None }]) }]
-Trait { name: Name(Text("Tr")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(0), auto: false, items: [Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::TraitDef>(0) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }]) }]
-> Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(1) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }]) }]
-> Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(2) }
-    "###);
 }
 
 #[test]
 fn impl_attrs() {
-    let tree = print_item_tree(
+    check(
         r#"
         #[impl_attr]
         impl Ty {
@@ -341,19 +348,18 @@ fn impl_attrs() {
             fn b() {}
         }
     "#,
+        expect![[r##"
+            inner attrs: Attrs { entries: None }
+
+            top-level items:
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("impl_attr"))] }, input: None }]) }]
+            Impl { generic_params: GenericParamsId(4294967295), target_trait: None, target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Ty"))] }, generic_args: [None] }), is_negative: false, items: [Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Impl>(0) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }]) }]
+            > Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(1) }
+            > #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }]) }]
+            > Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(2) }
+        "##]],
     );
-
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
-
-top-level items:
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("impl_attr"))] }, input: None }]) }]
-Impl { generic_params: GenericParamsId(4294967295), target_trait: None, target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("Ty"))] }, generic_args: [None] }), is_negative: false, items: [Function(Idx::<Function>(0)), Function(Idx::<Function>(1))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ImplDef>(0) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_a"))] }, input: None }]) }]
-> Function { name: Name(Text("a")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(1) }
-> #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("attr_b"))] }, input: None }]) }]
-> Function { name: Name(Text("b")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(2) }
-    "###);
 }
 
 #[test]
@@ -391,45 +397,43 @@ fn cursed_inner_items() {
 
 #[test]
 fn inner_item_attrs() {
-    let tree = print_item_tree(
+    check(
         r"
         fn foo() {
             #[on_inner]
             fn inner() {}
         }
     ",
-    );
-
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
+        expect![[r##"
+            inner attrs: Attrs { entries: None }
 
-top-level items:
-Function { name: Name(Text("foo")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(0) }
+            top-level items:
+            Function { name: Name(Text("foo")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(0) }
 
-inner items:
+            inner items:
 
-for AST FileAstId::<ra_syntax::ast::generated::nodes::ModuleItem>(1):
-#[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("on_inner"))] }, input: None }]) }]
-Function { name: Name(Text("inner")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::FnDef>(1) }
+            for AST FileAstId::<ra_syntax::ast::generated::nodes::Item>(1):
+            #[Attrs { entries: Some([Attr { path: ModPath { kind: Plain, segments: [Name(Text("on_inner"))] }, input: None }]) }]
+            Function { name: Name(Text("inner")), visibility: RawVisibilityId("pub(self)"), generic_params: GenericParamsId(4294967295), has_self_param: false, is_unsafe: false, params: [], is_varargs: false, ret_type: Tuple([]), ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Fn>(1) }
 
-    "###);
+        "##]],
+    );
 }
 
 #[test]
 fn assoc_item_macros() {
-    let tree = print_item_tree(
+    check(
         r"
         impl S {
             items!();
         }
     ",
-    );
-
-    assert_snapshot!(tree, @r###"
-inner attrs: Attrs { entries: None }
+        expect![[r#"
+            inner attrs: Attrs { entries: None }
 
-top-level items:
-Impl { generic_params: GenericParamsId(4294967295), target_trait: None, target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("S"))] }, generic_args: [None] }), is_negative: false, items: [MacroCall(Idx::<MacroCall>(0))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::ImplDef>(0) }
-> MacroCall { name: None, path: ModPath { kind: Plain, segments: [Name(Text("items"))] }, is_export: false, is_local_inner: false, is_builtin: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::MacroCall>(1) }
-    "###);
+            top-level items:
+            Impl { generic_params: GenericParamsId(4294967295), target_trait: None, target_type: Path(Path { type_anchor: None, mod_path: ModPath { kind: Plain, segments: [Name(Text("S"))] }, generic_args: [None] }), is_negative: false, items: [MacroCall(Idx::<MacroCall>(0))], ast_id: FileAstId::<ra_syntax::ast::generated::nodes::Impl>(0) }
+            > MacroCall { name: None, path: ModPath { kind: Plain, segments: [Name(Text("items"))] }, is_export: false, is_local_inner: false, is_builtin: false, ast_id: FileAstId::<ra_syntax::ast::generated::nodes::MacroCall>(1) }
+        "#]],
+    );
 }
diff --git a/crates/ra_hir_def/src/keys.rs b/crates/ra_hir_def/src/keys.rs
index a7349a21d..441bdbead 100644
--- a/crates/ra_hir_def/src/keys.rs
+++ b/crates/ra_hir_def/src/keys.rs
@@ -14,19 +14,19 @@ use crate::{
 
 pub type Key<K, V> = crate::dyn_map::Key<InFile<K>, V, AstPtrPolicy<K, V>>;
 
-pub const FUNCTION: Key<ast::FnDef, FunctionId> = Key::new();
-pub const CONST: Key<ast::ConstDef, ConstId> = Key::new();
-pub const STATIC: Key<ast::StaticDef, StaticId> = Key::new();
-pub const TYPE_ALIAS: Key<ast::TypeAliasDef, TypeAliasId> = Key::new();
-pub const IMPL: Key<ast::ImplDef, ImplId> = Key::new();
-pub const TRAIT: Key<ast::TraitDef, TraitId> = Key::new();
-pub const STRUCT: Key<ast::StructDef, StructId> = Key::new();
-pub const UNION: Key<ast::UnionDef, UnionId> = Key::new();
-pub const ENUM: Key<ast::EnumDef, EnumId> = Key::new();
-
-pub const ENUM_VARIANT: Key<ast::EnumVariant, EnumVariantId> = Key::new();
-pub const TUPLE_FIELD: Key<ast::TupleFieldDef, FieldId> = Key::new();
-pub const RECORD_FIELD: Key<ast::RecordFieldDef, FieldId> = Key::new();
+pub const FUNCTION: Key<ast::Fn, FunctionId> = Key::new();
+pub const CONST: Key<ast::Const, ConstId> = Key::new();
+pub const STATIC: Key<ast::Static, StaticId> = Key::new();
+pub const TYPE_ALIAS: Key<ast::TypeAlias, TypeAliasId> = Key::new();
+pub const IMPL: Key<ast::Impl, ImplId> = Key::new();
+pub const TRAIT: Key<ast::Trait, TraitId> = Key::new();
+pub const STRUCT: Key<ast::Struct, StructId> = Key::new();
+pub const UNION: Key<ast::Union, UnionId> = Key::new();
+pub const ENUM: Key<ast::Enum, EnumId> = Key::new();
+
+pub const VARIANT: Key<ast::Variant, EnumVariantId> = Key::new();
+pub const TUPLE_FIELD: Key<ast::TupleField, FieldId> = Key::new();
+pub const RECORD_FIELD: Key<ast::RecordField, FieldId> = Key::new();
 pub const TYPE_PARAM: Key<ast::TypeParam, TypeParamId> = Key::new();
 
 pub const MACRO: Key<ast::MacroCall, MacroDefId> = Key::new();
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 564434ccc..237b1038a 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -65,6 +65,7 @@ use item_tree::{
     Const, Enum, Function, Impl, ItemTreeId, ItemTreeNode, ModItem, Static, Struct, Trait,
     TypeAlias, Union,
 };
+use stdx::impl_from;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ModuleId {
@@ -158,17 +159,17 @@ pub struct FunctionId(salsa::InternId);
 type FunctionLoc = AssocItemLoc<Function>;
 impl_intern!(FunctionId, FunctionLoc, intern_function, lookup_intern_function);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct StructId(salsa::InternId);
 type StructLoc = ItemLoc<Struct>;
 impl_intern!(StructId, StructLoc, intern_struct, lookup_intern_struct);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct UnionId(salsa::InternId);
 pub type UnionLoc = ItemLoc<Union>;
 impl_intern!(UnionId, UnionLoc, intern_union, lookup_intern_union);
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct EnumId(salsa::InternId);
 pub type EnumLoc = ItemLoc<Enum>;
 impl_intern!(EnumId, EnumLoc, intern_enum, lookup_intern_enum);
@@ -223,25 +224,6 @@ pub struct TypeParamId {
 
 pub type LocalTypeParamId = Idx<generics::TypeParamData>;
 
-macro_rules! impl_froms {
-    ($e:ident: $($v:ident $(($($sv:ident),*))?),*) => {
-        $(
-            impl From<$v> for $e {
-                fn from(it: $v) -> $e {
-                    $e::$v(it)
-                }
-            }
-            $($(
-                impl From<$sv> for $e {
-                    fn from(it: $sv) -> $e {
-                        $e::$v($v::$sv(it))
-                    }
-                }
-            )*)?
-        )*
-    }
-}
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum ContainerId {
     ModuleId(ModuleId),
@@ -254,16 +236,16 @@ pub enum AssocContainerId {
     ImplId(ImplId),
     TraitId(TraitId),
 }
-impl_froms!(AssocContainerId: ContainerId);
+impl_from!(ContainerId for AssocContainerId);
 
 /// A Data Type
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub enum AdtId {
     StructId(StructId),
     UnionId(UnionId),
     EnumId(EnumId),
 }
-impl_froms!(AdtId: StructId, UnionId, EnumId);
+impl_from!(StructId, UnionId, EnumId for AdtId);
 
 /// The defs which can be visible in the module.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -279,8 +261,8 @@ pub enum ModuleDefId {
     TypeAliasId(TypeAliasId),
     BuiltinType(BuiltinType),
 }
-impl_froms!(
-    ModuleDefId: ModuleId,
+impl_from!(
+    ModuleId,
     FunctionId,
     AdtId(StructId, EnumId, UnionId),
     EnumVariantId,
@@ -289,6 +271,7 @@ impl_froms!(
     TraitId,
     TypeAliasId,
     BuiltinType
+    for ModuleDefId
 );
 
 /// The defs which have a body.
@@ -299,7 +282,7 @@ pub enum DefWithBodyId {
     ConstId(ConstId),
 }
 
-impl_froms!(DefWithBodyId: FunctionId, ConstId, StaticId);
+impl_from!(FunctionId, ConstId, StaticId for DefWithBodyId);
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum AssocItemId {
@@ -311,7 +294,7 @@ pub enum AssocItemId {
 // sure that you can only turn actual assoc items into AssocItemIds. This would
 // require not implementing From, and instead having some checked way of
 // casting them, and somehow making the constructors private, which would be annoying.
-impl_froms!(AssocItemId: FunctionId, ConstId, TypeAliasId);
+impl_from!(FunctionId, ConstId, TypeAliasId for AssocItemId);
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
 pub enum GenericDefId {
@@ -326,14 +309,15 @@ pub enum GenericDefId {
     // consts can have type parameters from their parents (i.e. associated consts of traits)
     ConstId(ConstId),
 }
-impl_froms!(
-    GenericDefId: FunctionId,
+impl_from!(
+    FunctionId,
     AdtId(StructId, EnumId, UnionId),
     TraitId,
     TypeAliasId,
     ImplId,
     EnumVariantId,
     ConstId
+    for GenericDefId
 );
 
 impl From<AssocItemId> for GenericDefId {
@@ -361,8 +345,8 @@ pub enum AttrDefId {
     ImplId(ImplId),
 }
 
-impl_froms!(
-    AttrDefId: ModuleId,
+impl_from!(
+    ModuleId,
     FieldId,
     AdtId(StructId, EnumId, UnionId),
     EnumVariantId,
@@ -373,6 +357,7 @@ impl_froms!(
     TypeAliasId,
     MacroDefId,
     ImplId
+    for AttrDefId
 );
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
@@ -381,7 +366,7 @@ pub enum VariantId {
     StructId(StructId),
     UnionId(UnionId),
 }
-impl_froms!(VariantId: EnumVariantId, StructId, UnionId);
+impl_from!(EnumVariantId, StructId, UnionId for VariantId);
 
 trait Intern {
     type ID;
@@ -536,7 +521,7 @@ impl AsMacroCall for AstIdWithPath<ast::MacroCall> {
     }
 }
 
-impl AsMacroCall for AstIdWithPath<ast::ModuleItem> {
+impl AsMacroCall for AstIdWithPath<ast::Item> {
     fn as_call_id(
         &self,
         db: &dyn db::DefDatabase,
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index b279bdeef..3d9b55a73 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -229,37 +229,37 @@ impl CrateDefMap {
     // even), as this should be a great debugging aid.
     pub fn dump(&self) -> String {
         let mut buf = String::new();
-        go(&mut buf, self, "\ncrate", self.root);
-        return buf.trim().to_string();
+        go(&mut buf, self, "crate", self.root);
+        return buf;
 
         fn go(buf: &mut String, map: &CrateDefMap, path: &str, module: LocalModuleId) {
-            *buf += path;
-            *buf += "\n";
+            format_to!(buf, "{}\n", path);
 
             let mut entries: Vec<_> = map.modules[module].scope.resolutions().collect();
             entries.sort_by_key(|(name, _)| name.clone());
 
             for (name, def) in entries {
-                format_to!(buf, "{}:", name);
+                format_to!(buf, "{}:", name.map_or("_".to_string(), |name| name.to_string()));
 
                 if def.types.is_some() {
-                    *buf += " t";
+                    buf.push_str(" t");
                 }
                 if def.values.is_some() {
-                    *buf += " v";
+                    buf.push_str(" v");
                 }
                 if def.macros.is_some() {
-                    *buf += " m";
+                    buf.push_str(" m");
                 }
                 if def.is_none() {
-                    *buf += " _";
+                    buf.push_str(" _");
                 }
 
-                *buf += "\n";
+                buf.push_str("\n");
             }
 
             for (name, child) in map.modules[module].children.iter() {
-                let path = &format!("{}::{}", path, name);
+                let path = format!("{}::{}", path, name);
+                buf.push('\n');
                 go(buf, map, &path, *child);
             }
         }
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index a35ac1024..28b7a20c5 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -36,6 +36,10 @@ use crate::{
     TraitLoc, TypeAliasLoc, UnionLoc,
 };
 
+const GLOB_RECURSION_LIMIT: usize = 100;
+const EXPANSION_DEPTH_LIMIT: usize = 128;
+const FIXED_POINT_LIMIT: usize = 8192;
+
 pub(super) fn collect_defs(db: &dyn DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
     let crate_graph = db.crate_graph();
 
@@ -166,7 +170,7 @@ struct MacroDirective {
 #[derive(Clone, Debug, Eq, PartialEq)]
 struct DeriveDirective {
     module_id: LocalModuleId,
-    ast_id: AstIdWithPath<ast::ModuleItem>,
+    ast_id: AstIdWithPath<ast::Item>,
 }
 
 struct DefData<'a> {
@@ -217,7 +221,7 @@ impl DefCollector<'_> {
                 ReachedFixedPoint::Yes => break,
                 ReachedFixedPoint::No => i += 1,
             }
-            if i == 10000 {
+            if i == FIXED_POINT_LIMIT {
                 log::error!("name resolution is stuck");
                 break;
             }
@@ -306,7 +310,7 @@ impl DefCollector<'_> {
         if export {
             self.update(
                 self.def_map.root,
-                &[(name, PerNs::macros(macro_, Visibility::Public))],
+                &[(Some(name), PerNs::macros(macro_, Visibility::Public))],
                 Visibility::Public,
                 ImportType::Named,
             );
@@ -332,7 +336,7 @@ impl DefCollector<'_> {
     fn define_proc_macro(&mut self, name: Name, macro_: MacroDefId) {
         self.update(
             self.def_map.root,
-            &[(name, PerNs::macros(macro_, Visibility::Public))],
+            &[(Some(name), PerNs::macros(macro_, Visibility::Public))],
             Visibility::Public,
             ImportType::Named,
         );
@@ -530,7 +534,7 @@ impl DefCollector<'_> {
                             let name = variant_data.name.clone();
                             let variant = EnumVariantId { parent: e, local_id };
                             let res = PerNs::both(variant.into(), variant.into(), vis);
-                            (name, res)
+                            (Some(name), res)
                         })
                         .collect::<Vec<_>>();
                     self.update(module_id, &resolutions, vis, ImportType::Glob);
@@ -546,15 +550,15 @@ impl DefCollector<'_> {
             match import.path.segments.last() {
                 Some(last_segment) => {
                     let name = match &import.alias {
-                        Some(ImportAlias::Alias(name)) => name.clone(),
-                        Some(ImportAlias::Underscore) => last_segment.clone(), // FIXME rust-analyzer#2736
-                        None => last_segment.clone(),
+                        Some(ImportAlias::Alias(name)) => Some(name.clone()),
+                        Some(ImportAlias::Underscore) => None,
+                        None => Some(last_segment.clone()),
                     };
                     log::debug!("resolved import {:?} ({:?}) to {:?}", name, import, def);
 
                     // extern crates in the crate root are special-cased to insert entries into the extern prelude: rust-lang/rust#54658
                     if import.is_extern_crate && module_id == self.def_map.root {
-                        if let Some(def) = def.take_types() {
+                        if let (Some(def), Some(name)) = (def.take_types(), name.as_ref()) {
                             self.def_map.extern_prelude.insert(name.clone(), def);
                         }
                     }
@@ -569,36 +573,73 @@ impl DefCollector<'_> {
     fn update(
         &mut self,
         module_id: LocalModuleId,
-        resolutions: &[(Name, PerNs)],
+        resolutions: &[(Option<Name>, PerNs)],
         vis: Visibility,
         import_type: ImportType,
     ) {
+        self.db.check_canceled();
         self.update_recursive(module_id, resolutions, vis, import_type, 0)
     }
 
     fn update_recursive(
         &mut self,
         module_id: LocalModuleId,
-        resolutions: &[(Name, PerNs)],
+        resolutions: &[(Option<Name>, PerNs)],
         // All resolutions are imported with this visibility; the visibilies in
         // the `PerNs` values are ignored and overwritten
         vis: Visibility,
         import_type: ImportType,
         depth: usize,
     ) {
-        if depth > 100 {
+        if depth > GLOB_RECURSION_LIMIT {
             // prevent stack overflows (but this shouldn't be possible)
             panic!("infinite recursion in glob imports!");
         }
-        let scope = &mut self.def_map.modules[module_id].scope;
         let mut changed = false;
+
         for (name, res) in resolutions {
-            changed |= scope.push_res_with_import(
-                &mut self.from_glob_import,
-                (module_id, name.clone()),
-                res.with_visibility(vis),
-                import_type,
-            );
+            match name {
+                Some(name) => {
+                    let scope = &mut self.def_map.modules[module_id].scope;
+                    changed |= scope.push_res_with_import(
+                        &mut self.from_glob_import,
+                        (module_id, name.clone()),
+                        res.with_visibility(vis),
+                        import_type,
+                    );
+                }
+                None => {
+                    let tr = match res.take_types() {
+                        Some(ModuleDefId::TraitId(tr)) => tr,
+                        Some(other) => {
+                            log::debug!("non-trait `_` import of {:?}", other);
+                            continue;
+                        }
+                        None => continue,
+                    };
+                    let old_vis = self.def_map.modules[module_id].scope.unnamed_trait_vis(tr);
+                    let should_update = match old_vis {
+                        None => true,
+                        Some(old_vis) => {
+                            let max_vis = old_vis.max(vis, &self.def_map).unwrap_or_else(|| {
+                                panic!("`Tr as _` imports with unrelated visibilities {:?} and {:?} (trait {:?})", old_vis, vis, tr);
+                            });
+
+                            if max_vis == old_vis {
+                                false
+                            } else {
+                                mark::hit!(upgrade_underscore_visibility);
+                                true
+                            }
+                        }
+                    };
+
+                    if should_update {
+                        changed = true;
+                        self.def_map.modules[module_id].scope.push_unnamed_trait(tr, vis);
+                    }
+                }
+            }
         }
 
         if !changed {
@@ -609,14 +650,15 @@ impl DefCollector<'_> {
             .get(&module_id)
             .into_iter()
             .flat_map(|v| v.iter())
+            .filter(|(glob_importing_module, _)| {
+                // we know all resolutions have the same visibility (`vis`), so we
+                // just need to check that once
+                vis.is_visible_from_def_map(&self.def_map, *glob_importing_module)
+            })
             .cloned()
             .collect::<Vec<_>>();
+
         for (glob_importing_module, glob_import_vis) in glob_imports {
-            // we know all resolutions have the same visibility (`vis`), so we
-            // just need to check that once
-            if !vis.is_visible_from_def_map(&self.def_map, glob_importing_module) {
-                continue;
-            }
             self.update_recursive(
                 glob_importing_module,
                 resolutions,
@@ -677,10 +719,6 @@ impl DefCollector<'_> {
         self.unexpanded_attribute_macros = attribute_macros;
 
         for (module_id, macro_call_id, depth) in resolved {
-            if depth > 1024 {
-                log::debug!("Max macro expansion depth reached");
-                continue;
-            }
             self.collect_macro_expansion(module_id, macro_call_id, depth);
         }
 
@@ -717,6 +755,11 @@ impl DefCollector<'_> {
         macro_call_id: MacroCallId,
         depth: usize,
     ) {
+        if depth > EXPANSION_DEPTH_LIMIT {
+            mark::hit!(macro_expansion_overflow);
+            log::warn!("macro expansion is too deep");
+            return;
+        }
         let file_id: HirFileId = macro_call_id.as_file();
         let item_tree = self.db.item_tree(file_id);
         let mod_dir = self.mod_dirs[&module_id].clone();
@@ -943,7 +986,7 @@ impl ModCollector<'_, '_> {
                         .unwrap_or(Visibility::Public);
                     self.def_collector.update(
                         self.module_id,
-                        &[(name.clone(), PerNs::from_def(id, vis, has_constructor))],
+                        &[(Some(name.clone()), PerNs::from_def(id, vis, has_constructor))],
                         vis,
                         ImportType::Named,
                     )
@@ -1050,14 +1093,14 @@ impl ModCollector<'_, '_> {
         self.def_collector.def_map.modules[self.module_id].scope.define_def(def);
         self.def_collector.update(
             self.module_id,
-            &[(name, PerNs::from_def(def, vis, false))],
+            &[(Some(name), PerNs::from_def(def, vis, false))],
             vis,
             ImportType::Named,
         );
         res
     }
 
-    fn collect_derives(&mut self, attrs: &Attrs, ast_id: FileAstId<ast::ModuleItem>) {
+    fn collect_derives(&mut self, attrs: &Attrs, ast_id: FileAstId<ast::Item>) {
         for derive_subtree in attrs.by_key("derive").tt_values() {
             // for #[derive(Copy, Clone)], `derive_subtree` is the `(Copy, Clone)` subtree
             for tt in &derive_subtree.token_trees {
diff --git a/crates/ra_hir_def/src/nameres/mod_resolution.rs b/crates/ra_hir_def/src/nameres/mod_resolution.rs
index 39e9a6d97..953961632 100644
--- a/crates/ra_hir_def/src/nameres/mod_resolution.rs
+++ b/crates/ra_hir_def/src/nameres/mod_resolution.rs
@@ -1,23 +1,24 @@
 //! This module resolves `mod foo;` declaration to file.
 use hir_expand::name::Name;
-use ra_db::{FileId, RelativePathBuf};
+use ra_db::FileId;
 use ra_syntax::SmolStr;
 
 use crate::{db::DefDatabase, HirFileId};
 
 #[derive(Clone, Debug)]
 pub(super) struct ModDir {
-    /// `.` for `mod.rs`, `lib.rs`
-    /// `./foo` for `foo.rs`
-    /// `./foo/bar` for `mod bar { mod x; }` nested in `foo.rs`
-    path: RelativePathBuf,
+    /// `` for `mod.rs`, `lib.rs`
+    /// `foo/` for `foo.rs`
+    /// `foo/bar/` for `mod bar { mod x; }` nested in `foo.rs`
+    /// Invariant: path.is_empty() || path.ends_with('/')
+    dir_path: DirPath,
     /// inside `./foo.rs`, mods with `#[path]` should *not* be relative to `./foo/`
     root_non_dir_owner: bool,
 }
 
 impl ModDir {
     pub(super) fn root() -> ModDir {
-        ModDir { path: RelativePathBuf::default(), root_non_dir_owner: false }
+        ModDir { dir_path: DirPath::empty(), root_non_dir_owner: false }
     }
 
     pub(super) fn descend_into_definition(
@@ -25,17 +26,21 @@ impl ModDir {
         name: &Name,
         attr_path: Option<&SmolStr>,
     ) -> ModDir {
-        let mut path = self.path.clone();
-        match attr_to_path(attr_path) {
-            None => path.push(&name.to_string()),
+        let path = match attr_path.map(|it| it.as_str()) {
+            None => {
+                let mut path = self.dir_path.clone();
+                path.push(&name.to_string());
+                path
+            }
             Some(attr_path) => {
-                if self.root_non_dir_owner {
-                    assert!(path.pop());
+                let mut path = self.dir_path.join_attr(attr_path, self.root_non_dir_owner);
+                if !(path.is_empty() || path.ends_with('/')) {
+                    path.push('/')
                 }
-                path.push(attr_path);
+                DirPath::new(path)
             }
-        }
-        ModDir { path, root_non_dir_owner: false }
+        };
+        ModDir { dir_path: path, root_non_dir_owner: false }
     }
 
     pub(super) fn resolve_declaration(
@@ -48,34 +53,87 @@ impl ModDir {
         let file_id = file_id.original_file(db.upcast());
 
         let mut candidate_files = Vec::new();
-        match attr_to_path(attr_path) {
+        match attr_path {
             Some(attr_path) => {
-                let base =
-                    if self.root_non_dir_owner { self.path.parent().unwrap() } else { &self.path };
-                candidate_files.push(base.join(attr_path).to_string())
+                candidate_files.push(self.dir_path.join_attr(attr_path, self.root_non_dir_owner))
             }
             None => {
-                candidate_files.push(self.path.join(&format!("{}.rs", name)).to_string());
-                candidate_files.push(self.path.join(&format!("{}/mod.rs", name)).to_string());
+                candidate_files.push(format!("{}{}.rs", self.dir_path.0, name));
+                candidate_files.push(format!("{}{}/mod.rs", self.dir_path.0, name));
             }
         };
 
         for candidate in candidate_files.iter() {