75 files changed, 1437 insertions, 504 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 330bdd1cb..efe8dd189 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -11,9 +11,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.26"
+version = "1.0.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7825f6833612eb2414095684fcf6c635becf3ce97fe48cf6421321e93bfbd53c"
+checksum = "013a6e0a2cbe3d20f9c60b65458f7a7f7a5e636c5d0f45a5a6aee5d4b1f01785"
 
 [[package]]
 name = "anymap"
@@ -58,9 +58,9 @@ dependencies = [
 
 [[package]]
 name = "backtrace-sys"
-version = "0.1.33"
+version = "0.1.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e17b52e737c40a7d75abca20b29a19a0eb7ba9fc72c5a72dd282a0a3c2c0dc35"
+checksum = "ca797db0057bae1a7aa2eef3283a874695455cecf08a43bfb8507ee0ebc1ed69"
 dependencies = [
  "cc",
  "libc",
@@ -80,9 +80,9 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
 [[package]]
 name = "bstr"
-version = "0.2.11"
+version = "0.2.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "502ae1441a0a5adb8fbd38a5955a6416b9493e92b465de5e4a9bde6a539c2c48"
+checksum = "2889e6d50f394968c8bf4240dc3f2a7eb4680844d27308f798229ac9d4725f41"
 dependencies = [
  "memchr",
 ]
@@ -940,6 +940,7 @@ dependencies = [
 name = "ra_hir"
 version = "0.1.0"
 dependencies = [
+ "arrayvec",
  "either",
  "itertools",
  "log",
@@ -1229,9 +1230,9 @@ checksum = "2439c63f3f6139d1b57529d16bc3b8bb855230c8efcc5d3a896c8bea7c3b1e84"
 
 [[package]]
 name = "regex"
-version = "1.3.4"
+version = "1.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "322cf97724bea3ee221b78fe25ac9c46114ebb51747ad5babd51a2fc6a8235a8"
+checksum = "8900ebc1363efa7ea1c399ccc32daed870b4002651e0bed86e72d501ebbe0048"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -1241,9 +1242,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.16"
+version = "0.6.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1132f845907680735a84409c3bebc64d1364a5683ffbce899550cd09d5eaefc1"
+checksum = "7fe5bd57d1d7414c6b5ed48563a2c855d995ff777729dcd91c369ec7fea395ae"
 
 [[package]]
 name = "relative-path"
@@ -1341,9 +1342,9 @@ dependencies = [
 
 [[package]]
 name = "ryu"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bfa8506c1de11c9c4e4c38863ccbe02a305c8188e85a05a784c9e11e1c3910c8"
+checksum = "535622e6be132bccd223f4bb2b8ac8d53cda3c7a6394944d3b2b33fb974f9d76"
 
 [[package]]
 name = "salsa"
diff --git a/crates/ra_assists/src/ast_transform.rs b/crates/ra_assists/src/ast_transform.rs
index 42856f0ca..45558c448 100644
--- a/crates/ra_assists/src/ast_transform.rs
+++ b/crates/ra_assists/src/ast_transform.rs
@@ -37,7 +37,6 @@ pub struct SubstituteTypeParams<'a> {
 impl<'a> SubstituteTypeParams<'a> {
     pub fn for_trait_impl(
         source_scope: &'a SemanticsScope<'a, RootDatabase>,
-        db: &'a RootDatabase,
         // FIXME: there's implicit invariant that `trait_` and  `source_scope` match...
         trait_: hir::Trait,
         impl_def: ast::ImplDef,
@@ -45,7 +44,7 @@ impl<'a> SubstituteTypeParams<'a> {
         let substs = get_syntactic_substs(impl_def).unwrap_or_default();
         let generic_def: hir::GenericDef = trait_.into();
         let substs_by_param: FxHashMap<_, _> = generic_def
-            .params(db)
+            .params(source_scope.db)
             .into_iter()
             // this is a trait impl, so we need to skip the first type parameter -- this is a bit hacky
             .skip(1)
@@ -104,7 +103,6 @@ impl<'a> AstTransform<'a> for SubstituteTypeParams<'a> {
 pub struct QualifyPaths<'a> {
     target_scope: &'a SemanticsScope<'a, RootDatabase>,
     source_scope: &'a SemanticsScope<'a, RootDatabase>,
-    db: &'a RootDatabase,
     previous: Box<dyn AstTransform<'a> + 'a>,
 }
 
@@ -112,9 +110,8 @@ impl<'a> QualifyPaths<'a> {
     pub fn new(
         target_scope: &'a SemanticsScope<'a, RootDatabase>,
         source_scope: &'a SemanticsScope<'a, RootDatabase>,
-        db: &'a RootDatabase,
     ) -> Self {
-        Self { target_scope, source_scope, db, previous: Box::new(NullTransformer) }
+        Self { target_scope, source_scope, previous: Box::new(NullTransformer) }
     }
 
     fn get_substitution_inner(
@@ -132,7 +129,7 @@ impl<'a> QualifyPaths<'a> {
         let resolution = self.source_scope.resolve_hir_path(&hir_path?)?;
         match resolution {
             PathResolution::Def(def) => {
-                let found_path = from.find_use_path(self.db, def)?;
+                let found_path = from.find_use_path(self.source_scope.db, def)?;
                 let mut path = path_to_ast(found_path);
 
                 let type_args = p
diff --git a/crates/ra_assists/src/handlers/add_missing_impl_members.rs b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
index 639180d37..e5920b6f6 100644
--- a/crates/ra_assists/src/handlers/add_missing_impl_members.rs
+++ b/crates/ra_assists/src/handlers/add_missing_impl_members.rs
@@ -142,8 +142,8 @@ fn add_missing_impl_members_inner(
         let n_existing_items = impl_item_list.impl_items().count();
         let source_scope = sema.scope_for_def(trait_);
         let target_scope = sema.scope(impl_item_list.syntax());
-        let ast_transform = QualifyPaths::new(&target_scope, &source_scope, sema.db)
-            .or(SubstituteTypeParams::for_trait_impl(&source_scope, sema.db, trait_, impl_node));
+        let ast_transform = QualifyPaths::new(&target_scope, &source_scope)
+            .or(SubstituteTypeParams::for_trait_impl(&source_scope, trait_, impl_node));
         let items = missing_items
             .into_iter()
             .map(|it| ast_transform::apply(&*ast_transform, it))
diff --git a/crates/ra_assists/src/handlers/fill_match_arms.rs b/crates/ra_assists/src/handlers/fill_match_arms.rs
index e5d8c639d..97cf90ae4 100644
--- a/crates/ra_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ra_assists/src/handlers/fill_match_arms.rs
@@ -2,7 +2,7 @@
 
 use std::iter;
 
-use hir::{db::HirDatabase, Adt, HasSource, Semantics};
+use hir::{Adt, HasSource, Semantics};
 use ra_syntax::ast::{self, edit::IndentLevel, make, AstNode, NameOwner};
 
 use crate::{Assist, AssistCtx, AssistId};
@@ -88,11 +88,7 @@ fn resolve_enum_def(sema: &Semantics<RootDatabase>, expr: &ast::Expr) -> Option<
     })
 }
 
-fn build_pat(
-    db: &impl HirDatabase,
-    module: hir::Module,
-    var: hir::EnumVariant,
-) -> Option<ast::Pat> {
+fn build_pat(db: &RootDatabase, module: hir::Module, var: hir::EnumVariant) -> Option<ast::Pat> {
     let path = crate::ast_transform::path_to_ast(module.find_use_path(db, var.into())?);
 
     // FIXME: use HIR for this; it doesn't currently expose struct vs. tuple vs. unit variants though
diff --git a/crates/ra_db/src/fixture.rs b/crates/ra_db/src/fixture.rs
index 3dc86ca2d..3464f43df 100644
--- a/crates/ra_db/src/fixture.rs
+++ b/crates/ra_db/src/fixture.rs
@@ -64,7 +64,9 @@ fn with_single_file(db: &mut dyn SourceDatabaseExt, ra_fixture: &str) -> FileId
         crate_graph.add_crate_root(
             file_id,
             meta.edition,
-            meta.krate,
+            meta.krate.map(|name| {
+                CrateName::new(&name).expect("Fixture crate name should not contain dashes")
+            }),
             meta.cfg,
             meta.env,
             Default::default(),
@@ -124,7 +126,7 @@ fn with_files(db: &mut dyn SourceDatabaseExt, fixture: &str) -> Option<FilePosit
             let crate_id = crate_graph.add_crate_root(
                 file_id,
                 meta.edition,
-                Some(krate.clone()),
+                Some(CrateName::new(&krate).unwrap()),
                 meta.cfg,
                 meta.env,
                 Default::default(),
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index 06d40db96..bde843001 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -14,6 +14,7 @@ use rustc_hash::FxHashMap;
 use rustc_hash::FxHashSet;
 
 use crate::{RelativePath, RelativePathBuf};
+use fmt::Display;
 
 /// `FileId` is an integer which uniquely identifies a file. File paths are
 /// messy and system-dependent, so most of the code should work directly with
@@ -83,6 +84,7 @@ pub struct CrateGraph {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct CrateId(pub u32);
 
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct CrateName(SmolStr);
 
 impl CrateName {
@@ -103,6 +105,12 @@ impl CrateName {
     }
 }
 
+impl Display for CrateName {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct CrateData {
     pub root_file_id: FileId,
@@ -110,7 +118,7 @@ pub struct CrateData {
     /// The name to display to the end user.
     /// This actual crate name can be different in a particular dependent crate
     /// or may even be missing for some cases, such as a dummy crate for the code snippet.
-    pub display_name: Option<String>,
+    pub display_name: Option<CrateName>,
     pub cfg_options: CfgOptions,
     pub env: Env,
     pub extern_source: ExternSource,
@@ -150,7 +158,7 @@ impl CrateGraph {
         &mut self,
         file_id: FileId,
         edition: Edition,
-        display_name: Option<String>,
+        display_name: Option<CrateName>,
         cfg_options: CfgOptions,
         env: Env,
         extern_source: ExternSource,
diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index 266c4cff3..42193b492 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -11,6 +11,7 @@ doctest = false
 log = "0.4.8"
 rustc-hash = "1.1.0"
 either = "1.5.3"
+arrayvec = "0.5.1"
 
 itertools = "0.8.2"
 
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 41d4e2ed3..ff041150b 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -1,6 +1,7 @@
 //! FIXME: write short doc here
 use std::sync::Arc;
 
+use arrayvec::ArrayVec;
 use either::Either;
 use hir_def::{
     adt::StructKind,
@@ -226,7 +227,9 @@ impl Module {
                     Some((name, def))
                 }
             })
-            .map(|(name, def)| (name.clone(), def.into()))
+            .flat_map(|(name, def)| {
+                ScopeDef::all_items(def).into_iter().map(move |item| (name.clone(), item))
+            })
             .collect()
     }
 
@@ -308,7 +311,11 @@ impl StructField {
         self.parent.variant_data(db).fields()[self.id].name.clone()
     }
 
-    pub fn ty(&self, db: &impl HirDatabase) -> Type {
+    /// Returns the type as in the signature of the struct (i.e., with
+    /// placeholder types for type parameters). This is good for showing
+    /// signature help, but not so good to actually get the type of the field
+    /// when you actually have a variable of the struct.
+    pub fn signature_ty(&self, db: &impl HirDatabase) -> Type {
         let var_id = self.parent.into();
         let generic_def_id: GenericDefId = match self.parent {
             VariantDef::Struct(it) => it.id.into(),
@@ -482,6 +489,10 @@ impl Adt {
         let subst = db.generic_defaults(self.into());
         subst.iter().any(|ty| ty == &Ty::Unknown)
     }
+
+    /// Turns this ADT into a type. Any type parameters of the ADT will be
+    /// turned into unknown types, which is good for e.g. finding the most
+    /// general set of completions, but will not look very nice when printed.
     pub fn ty(self, db: &impl HirDatabase) -> Type {
         let id = AdtId::from(self);
         Type::from_def(db, id.module(db).krate, id)
@@ -1028,7 +1039,7 @@ impl Type {
         krate: CrateId,
         def: impl HasResolver + Into<TyDefId> + Into<GenericDefId>,
     ) -> Type {
-        let substs = Substs::type_params(db, def);
+        let substs = Substs::build_for_def(db, def).fill_with_unknown().build();
         let ty = db.ty(def.into()).subst(&substs);
         Type::new(db, krate, def, ty)
     }
@@ -1288,15 +1299,36 @@ pub enum ScopeDef {
     Unknown,
 }
 
-impl From<PerNs> for ScopeDef {
-    fn from(def: PerNs) -> Self {
-        def.take_types()
-            .or_else(|| def.take_values())
-            .map(|module_def_id| ScopeDef::ModuleDef(module_def_id.into()))
-            .or_else(|| {
-                def.take_macros().map(|macro_def_id| ScopeDef::MacroDef(macro_def_id.into()))
-            })
-            .unwrap_or(ScopeDef::Unknown)
+impl ScopeDef {
+    pub fn all_items(def: PerNs) -> ArrayVec<[Self; 3]> {
+        let mut items = ArrayVec::new();
+
+        match (def.take_types(), def.take_values()) {
+            (Some(m1), None) => items.push(ScopeDef::ModuleDef(m1.into())),
+            (None, Some(m2)) => items.push(ScopeDef::ModuleDef(m2.into())),
+            (Some(m1), Some(m2)) => {
+                // Some items, like unit structs and enum variants, are
+                // returned as both a type and a value. Here we want
+                // to de-duplicate them.
+                if m1 != m2 {
+                    items.push(ScopeDef::ModuleDef(m1.into()));
+                    items.push(ScopeDef::ModuleDef(m2.into()));
+                } else {
+                    items.push(ScopeDef::ModuleDef(m1.into()));
+                }
+            }
+            (None, None) => {}
+        };
+
+        if let Some(macro_def_id) = def.take_macros() {
+            items.push(ScopeDef::MacroDef(macro_def_id.into()));
+        }
+
+        if items.is_empty() {
+            items.push(ScopeDef::Unknown);
+        }
+
+        items
     }
 }
 
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 3782a9984..788bb3eb7 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -344,7 +344,13 @@ impl<'a, DB: HirDatabase> SemanticsScope<'a, DB> {
 
         resolver.process_all_names(self.db, &mut |name, def| {
             let def = match def {
-                resolver::ScopeDef::PerNs(it) => it.into(),
+                resolver::ScopeDef::PerNs(it) => {
+                    let items = ScopeDef::all_items(it);
+                    for item in items {
+                        f(name.clone(), item);
+                    }
+                    return;
+                }
                 resolver::ScopeDef::ImplSelfType(it) => ScopeDef::ImplSelfType(it.into()),
                 resolver::ScopeDef::AdtSelfType(it) => ScopeDef::AdtSelfType(it.into()),
                 resolver::ScopeDef::GenericParam(id) => ScopeDef::GenericParam(TypeParam { id }),
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 57ba45b45..2bc405a59 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -47,13 +47,19 @@ impl Expander {
     pub(crate) fn enter_expand<T: ast::AstNode, DB: DefDatabase>(
         &mut self,
         db: &DB,
+        local_scope: Option<&ItemScope>,
         macro_call: ast::MacroCall,
     ) -> Option<(Mark, T)> {
         let macro_call = InFile::new(self.current_file_id, &macro_call);
 
-        if let Some(call_id) =
-            macro_call.as_call_id(db, |path| self.resolve_path_as_macro(db, &path))
-        {
+        if let Some(call_id) = macro_call.as_call_id(db, |path| {
+            if let Some(local_scope) = local_scope {
+                if let Some(def) = path.as_ident().and_then(|n| local_scope.get_legacy_macro(n)) {
+                    return Some(def);
+                }
+            }
+            self.resolve_path_as_macro(db, &path)
+        }) {
             let file_id = call_id.as_file();
             if let Some(node) = db.parse_or_expand(file_id) {
                 if let Some(expr) = T::cast(node) {
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index ec1b0c2e7..54b5591d3 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -3,7 +3,10 @@
 
 use either::Either;
 
-use hir_expand::name::{name, AsName, Name};
+use hir_expand::{
+    name::{name, AsName, Name},
+    MacroDefId, MacroDefKind,
+};
 use ra_arena::Arena;
 use ra_syntax::{
     ast::{
@@ -452,19 +455,30 @@ where
                     None => self.alloc_expr(Expr::Missing, syntax_ptr),
                 }
             }
-            // FIXME expand to statements in statement position
             ast::Expr::MacroCall(e) => {
-                let macro_call = self.expander.to_source(AstPtr::new(&e));
-                match self.expander.enter_expand(self.db, e) {
-                    Some((mark, expansion)) => {
-                        self.source_map
-                            .expansions
-                            .insert(macro_call, self.expander.current_file_id);
-                        let id = self.collect_expr(expansion);
-                        self.expander.exit(self.db, mark);
-                        id
+                if let Some(name) = is_macro_rules(&e) {
+                    let mac = MacroDefId {
+                        krate: Some(self.expander.module.krate),
+                        ast_id: Some(self.expander.ast_id(&e)),
+                        kind: MacroDefKind::Declarative,
+                    };
+                    self.body.item_scope.define_legacy_macro(name, mac);
+
+                    // FIXME: do we still need to allocate this as missing ?
+                    self.alloc_expr(Expr::Missing, syntax_ptr)
+                } else {
+                    let macro_call = self.expander.to_source(AstPtr::new(&e));
+                    match self.expander.enter_expand(self.db, Some(&self.body.item_scope), e) {
+                        Some((mark, expansion)) => {
+                            self.source_map
+                                .expansions
+                                .insert(macro_call, self.expander.current_file_id);
+                            let id = self.collect_expr(expansion);
+                            self.expander.exit(self.db, mark);
+                            id
+                        }
+                        None => self.alloc_expr(Expr::Missing, syntax_ptr),
                     }
-                    None => self.alloc_expr(Expr::Missing, syntax_ptr),
                 }
             }
 
@@ -686,6 +700,16 @@ where
     }
 }
 
+fn is_macro_rules(m: &ast::MacroCall) -> Option<Name> {
+    let name = m.path()?.segment()?.name_ref()?.as_name();
+
+    if name == name![macro_rules] {
+        Some(m.name()?.as_name())
+    } else {
+        None
+    }
+}
+
 impl From<ast::BinOp> for BinaryOp {
     fn from(ast_op: ast::BinOp) -> Self {
         match ast_op {
diff --git a/crates/ra_hir_def/src/data.rs b/crates/ra_hir_def/src/data.rs
index a72eb5369..c0b16b7fa 100644
--- a/crates/ra_hir_def/src/data.rs
+++ b/crates/ra_hir_def/src/data.rs
@@ -34,7 +34,8 @@ pub struct FunctionData {
 
 impl FunctionData {
     pub(crate) fn fn_data_query(db: &impl DefDatabase, func: FunctionId) -> Arc<FunctionData> {
-        let src = func.lookup(db).source(db);
+        let loc = func.lookup(db);
+        let src = loc.source(db);
         let name = src.value.name().map(|n| n.as_name()).unwrap_or_else(Name::missing);
         let mut params = Vec::new();
         let mut has_self_param = false;
@@ -76,7 +77,9 @@ impl FunctionData {
             ret_type
         };
 
-        let visibility = RawVisibility::from_ast(db, src.map(|s| s.visibility()));
+        let vis_default = RawVisibility::default_for_container(loc.container);
+        let visibility =
+            RawVisibility::from_ast_with_default(db, vis_default, src.map(|s| s.visibility()));
 
         let sig = FunctionData { name, params, ret_type, has_self_param, visibility };
         Arc::new(sig)
@@ -105,10 +108,13 @@ impl TypeAliasData {
         db: &impl DefDatabase,
         typ: TypeAliasId,
     ) -> Arc<TypeAliasData> {
-        let node = typ.lookup(db).source(db);
+        let loc = typ.lookup(db);
+        let node = loc.source(db);
         let name = node.value.name().map_or_else(Name::missing, |n| n.as_name());
         let type_ref = node.value.type_ref().map(TypeRef::from_ast);
-        let visibility = RawVisibility::from_ast(db, node.map(|n| n.visibility()));
+        let vis_default = RawVisibility::default_for_container(loc.container);
+        let visibility =
+            RawVisibility::from_ast_with_default(db, vis_default, node.map(|n| n.visibility()));
         Arc::new(TypeAliasData { name, type_ref, visibility })
     }
 }
@@ -230,22 +236,26 @@ pub struct ConstData {
 
 impl ConstData {
     pub(crate) fn const_data_query(db: &impl DefDatabase, konst: ConstId) -> Arc<ConstData> {
-        let node = konst.lookup(db).source(db);
-        Arc::new(ConstData::new(db, node))
+        let loc = konst.lookup(db);
+        let node = loc.source(db);
+        let vis_default = RawVisibility::default_for_container(loc.container);
+        Arc::new(ConstData::new(db, vis_default, node))
     }
 
     pub(crate) fn static_data_query(db: &impl DefDatabase, konst: StaticId) -> Arc<ConstData> {
         let node = konst.lookup(db).source(db);
-        Arc::new(ConstData::new(db, node))
+        Arc::new(ConstData::new(db, RawVisibility::private(), node))
     }
 
     fn new<N: NameOwner + TypeAscriptionOwner + VisibilityOwner>(
         db: &impl DefDatabase,
+        vis_default: RawVisibility,
         node: InFile<N>,
     ) -> ConstData {
         let name = node.value.name().map(|n| n.as_name());
         let type_ref = TypeRef::from_ast_opt(node.value.ascribed_type());
-        let visibility = RawVisibility::from_ast(db, node.map(|n| n.visibility()));
+        let visibility =
+            RawVisibility::from_ast_with_default(db, vis_default, node.map(|n| n.visibility()));
         ConstData { name, type_ref, visibility }
     }
 }
@@ -280,7 +290,7 @@ fn collect_impl_items_in_macro(
         return Vec::new();
     }
 
-    if let Some((mark, items)) = expander.enter_expand(db, m) {
+    if let Some((mark, items)) = expander.enter_expand(db, None, m) {
         let items: InFile<ast::MacroItems> = expander.to_source(items);
         let mut res = collect_impl_items(
             db,
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index 81eac52ad..03515309e 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -177,8 +177,13 @@ pub struct ModuleData {
 
 impl CrateDefMap {
     pub(crate) fn crate_def_map_query(db: &impl DefDatabase, krate: CrateId) -> Arc<CrateDefMap> {
-        let _p = profile("crate_def_map_query")
-            .detail(|| db.crate_graph()[krate].display_name.clone().unwrap_or_default());
+        let _p = profile("crate_def_map_query").detail(|| {
+            db.crate_graph()[krate]
+                .display_name
+                .as_ref()
+                .map(ToString::to_string)
+                .unwrap_or_default()
+        });
         let def_map = {
             let edition = db.crate_graph()[krate].edition;
             let mut modules: Arena<LocalModuleId, ModuleData> = Arena::default();
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index d0459d9b0..db9838cb5 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -102,6 +102,7 @@ struct MacroDirective {
     module_id: LocalModuleId,
     ast_id: AstIdWithPath<ast::MacroCall>,
     legacy: Option<MacroCallId>,
+    depth: usize,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]
@@ -134,6 +135,7 @@ where
         self.def_map.modules[module_id].origin = ModuleOrigin::CrateRoot { definition: file_id };
         ModCollector {
             def_collector: &mut *self,
+            macro_depth: 0,
             module_id,
             file_id: file_id.into(),
             raw_items: &raw_items,
@@ -516,7 +518,7 @@ where
         macros.retain(|directive| {
             if let Some(call_id) = directive.legacy {
                 res = ReachedFixedPoint::No;
-                resolved.push((directive.module_id, call_id));
+                resolved.push((directive.module_id, call_id, directive.depth));
                 return false;
             }
 
@@ -530,7 +532,7 @@ where
                 );
                 resolved_res.resolved_def.take_macros()
             }) {
-                resolved.push((directive.module_id, call_id));
+                resolved.push((directive.module_id, call_id, directive.depth));
                 res = ReachedFixedPoint::No;
                 return false;
             }
@@ -541,7 +543,7 @@ where
             if let Some(call_id) =
                 directive.ast_id.as_call_id(self.db, |path| self.resolve_attribute_macro(&path))
             {
-                resolved.push((directive.module_id, call_id));
+                resolved.push((directive.module_id, call_id, 0));
                 res = ReachedFixedPoint::No;
                 return false;
             }
@@ -552,8 +554,12 @@ where
         self.unexpanded_macros = macros;
         self.unexpanded_attribute_macros = attribute_macros;
 
-        for (module_id, macro_call_id) in resolved {
-            self.collect_macro_expansion(module_id, macro_call_id);
+        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);
         }
 
         res
@@ -573,12 +579,18 @@ where
         None
     }
 
-    fn collect_macro_expansion(&mut self, module_id: LocalModuleId, macro_call_id: MacroCallId) {
+    fn collect_macro_expansion(
+        &mut self,
+        module_id: LocalModuleId,
+        macro_call_id: MacroCallId,
+        depth: usize,
+    ) {
         let file_id: HirFileId = macro_call_id.as_file();
         let raw_items = self.db.raw_items(file_id);
         let mod_dir = self.mod_dirs[&module_id].clone();
         ModCollector {
             def_collector: &mut *self,
+            macro_depth: depth,
             file_id,
             module_id,
             raw_items: &raw_items,
@@ -595,6 +607,7 @@ where
 /// Walks a single module, populating defs, imports and macros
 struct ModCollector<'a, D> {
     def_collector: D,
+    macro_depth: usize,
     module_id: LocalModuleId,
     file_id: HirFileId,
     raw_items: &'a raw::RawItems,
@@ -684,6 +697,7 @@ where
 
                 ModCollector {
                     def_collector: &mut *self.def_collector,
+                    macro_depth: self.macro_depth,
                     module_id,
                     file_id: self.file_id,
                     raw_items: self.raw_items,
@@ -713,6 +727,7 @@ where
                         let raw_items = self.def_collector.db.raw_items(file_id.into());
                         ModCollector {
                             def_collector: &mut *self.def_collector,
+                            macro_depth: self.macro_depth,
                             module_id,
                             file_id: file_id.into(),
                             raw_items: &raw_items,
@@ -887,6 +902,7 @@ where
                 module_id: self.module_id,
                 ast_id,
                 legacy: Some(macro_call_id),
+                depth: self.macro_depth + 1,
             });
 
             return;
@@ -902,6 +918,7 @@ where
             module_id: self.module_id,
             ast_id,
             legacy: None,
+            depth: self.macro_depth + 1,
         });
     }
 
@@ -971,13 +988,26 @@ mod tests {
     }
 
     #[test]
-    fn test_macro_expand_will_stop() {
+    fn test_macro_expand_will_stop_1() {
+        do_resolve(
+            r#"
+        macro_rules! foo {
+            ($($ty:ty)*) => { foo!($($ty)*); }
+        }
+        foo!(KABOOM);
+        "#,
+        );
+    }
+
+    #[ignore] // this test does succeed, but takes quite a while :/
+    #[test]
+    fn test_macro_expand_will_stop_2() {
         do_resolve(
             r#"
         macro_rules! foo {
-            ($($ty:ty)*) => { foo!($($ty)*, $($ty)*); }
+            ($($ty:ty)*) => { foo!($($ty)* $($ty)*); }
         }
-foo!(KABOOM);
+        foo!(KABOOM);
         "#,
         );
     }
diff --git a/crates/ra_hir_def/src/nameres/tests.rs b/crates/ra_hir_def/src/nameres/tests.rs
index dda5ed699..3f33a75b9 100644
--- a/crates/ra_hir_def/src/nameres/tests.rs
+++ b/crates/ra_hir_def/src/nameres/tests.rs
@@ -102,6 +102,28 @@ fn crate_def_map_super_super() {
 }
 
 #[test]
+fn crate_def_map_fn_mod_same_name() {
+    let map = def_map(
+        "
+        //- /lib.rs
+        mod m {
+            pub mod z {}
+            pub fn z() {}
+        }
+        ",
+    );
+    assert_snapshot!(map, @r###"
+        ⋮crate
+        ⋮m: t
+        ⋮
+        ⋮crate::m
+        ⋮z: t v
+        ⋮
+        ⋮crate::m::z
+    "###)
+}
+
+#[test]
 fn bogus_paths() {
     covers!(bogus_paths);
     let map = def_map(
diff --git a/crates/ra_hir_def/src/resolver.rs b/crates/ra_hir_def/src/resolver.rs
index 2734d51a0..123fae72a 100644
--- a/crates/ra_hir_def/src/resolver.rs
+++ b/crates/ra_hir_def/src/resolver.rs
@@ -381,6 +381,11 @@ impl Resolver {
         db: &impl DefDatabase,
         path: &ModPath,
     ) -> Option<MacroDefId> {
+        // Search item scope legacy macro first
+        if let Some(def) = self.resolve_local_macro_def(path) {
+            return Some(def);
+        }
+
         let (item_map, module) = self.module_scope()?;
         item_map.resolve_path(db, module, &path, BuiltinShadowMode::Other).0.take_macros()
     }
@@ -413,6 +418,16 @@ impl Resolver {
         })
     }
 
+    fn resolve_local_macro_def(&self, path: &ModPath) -> Option<MacroDefId> {
+        let name = path.as_ident()?;
+        self.scopes.iter().rev().find_map(|scope| {
+            if let Scope::LocalItemsScope(body) = scope {
+                return body.item_scope.get_legacy_macro(name);
+            }
+            None
+        })
+    }
+
     pub fn module(&self) -> Option<ModuleId> {
         let (def_map, local_id) = self.module_scope()?;
         Some(ModuleId { krate: def_map.krate, local_id })
diff --git a/crates/ra_hir_def/src/visibility.rs b/crates/ra_hir_def/src/visibility.rs
index d8296da4b..e0c59e905 100644
--- a/crates/ra_hir_def/src/visibility.rs
+++ b/crates/ra_hir_def/src/visibility.rs
@@ -6,7 +6,7 @@ use ra_syntax::ast;
 use crate::{
     db::DefDatabase,
     path::{ModPath, PathKind},
-    ModuleId,
+    AssocContainerId, ModuleId,
 };
 
 /// Visibility of an item, not yet resolved.
@@ -20,11 +20,30 @@ pub enum RawVisibility {
 }
 
 impl RawVisibility {
-    const fn private() -> RawVisibility {
+    pub(crate) const fn private() -> RawVisibility {
         let path = ModPath { kind: PathKind::Super(0), segments: Vec::new() };
         RawVisibility::Module(path)
     }
 
+    pub(crate) fn default_for_container(container_id: AssocContainerId) -> Self {
+        match container_id {
+            AssocContainerId::TraitId(_) => RawVisibility::Public,
+            _ => RawVisibility::private(),
+        }
+    }
+
+    pub(crate) fn from_ast_with_default(
+        db: &impl DefDatabase,
+        default: RawVisibility,
+        node: InFile<Option<ast::Visibility>>,
+    ) -> RawVisibility {
+        Self::from_ast_with_hygiene_and_default(
+            node.value,
+            default,
+            &Hygiene::new(db, node.file_id),
+        )
+    }
+
     pub(crate) fn from_ast(
         db: &impl DefDatabase,
         node: InFile<Option<ast::Visibility>>,
@@ -36,8 +55,16 @@ impl RawVisibility {
         node: Option<ast::Visibility>,
         hygiene: &Hygiene,
     ) -> RawVisibility {
+        Self::from_ast_with_hygiene_and_default(node, RawVisibility::private(), hygiene)
+    }
+
+    pub(crate) fn from_ast_with_hygiene_and_default(
+        node: Option<ast::Visibility>,
+        default: RawVisibility,
+        hygiene: &Hygiene,
+    ) -> RawVisibility {
         let node = match node {
-            None => return RawVisibility::private(),
+            None => return default,
             Some(node) => node,
         };
         match node.kind() {
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 3fce73e8a..7b72eb7a0 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -17,7 +17,7 @@ pub mod eager;
 use std::hash::Hash;
 use std::sync::Arc;
 
-use ra_db::{salsa, CrateId, FileId};
+use ra_db::{impl_intern_key, salsa, CrateId, FileId};
 use ra_syntax::{
     algo,
     ast::{self, AstNode},
@@ -174,25 +174,11 @@ pub enum MacroCallId {
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct LazyMacroId(salsa::InternId);
-impl salsa::InternKey for LazyMacroId {
-    fn from_intern_id(v: salsa::InternId) -> Self {
-        LazyMacroId(v)
-    }
-    fn as_intern_id(&self) -> salsa::InternId {
-        self.0
-    }
-}
+impl_intern_key!(LazyMacroId);
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct EagerMacroId(salsa::InternId);
-impl salsa::InternKey for EagerMacroId {
-    fn from_intern_id(v: salsa::InternId) -> Self {
-        EagerMacroId(v)
-    }
-    fn as_intern_id(&self) -> salsa::InternId {
-        self.0
-    }
-}
+impl_intern_key!(EagerMacroId);
 
 impl From<LazyMacroId> for MacroCallId {
     fn from(it: LazyMacroId) -> Self {
diff --git a/crates/ra_hir_ty/src/tests/macros.rs b/crates/ra_hir_ty/src/tests/macros.rs
index 32457bbf7..3b7022ad5 100644
--- a/crates/ra_hir_ty/src/tests/macros.rs
+++ b/crates/ra_hir_ty/src/tests/macros.rs
@@ -363,6 +363,26 @@ fn main() {
 }
 
 #[test]
+fn infer_local_macro() {
+    assert_snapshot!(
+        infer(r#"
+fn main() {
+    macro_rules! foo {
+        () => { 1usize }
+    }
+    let _a  = foo!();
+}
+"#),
+        @r###"
+        ![0; 6) '1usize': usize
+        [11; 90) '{     ...!(); }': ()
+        [17; 66) 'macro_...     }': {unknown}
+        [75; 77) '_a': usize
+    "###
+    );
+}
+
+#[test]
 fn infer_builtin_macros_line() {
     assert_snapshot!(
         infer(r#"
diff --git a/crates/ra_ide/src/call_info.rs b/crates/ra_ide/src/call_info.rs
index 2b35a3803..39d09a07f 100644
--- a/crates/ra_ide/src/call_info.rs
+++ b/crates/ra_ide/src/call_info.rs
@@ -544,6 +544,20 @@ fn main() {
     }
 
     #[test]
+    fn generic_struct() {
+        let info = call_info(
+            r#"
+struct TS<T>(T);
+fn main() {
+    let s = TS(<|>);
+}"#,
+        );
+
+        assert_eq!(info.label(), "struct TS<T>(T) -> TS");
+        assert_eq!(info.active_parameter, Some(0));
+    }
+
+    #[test]
     #[should_panic]
     fn cant_call_named_structs() {
         let _ = call_info(
diff --git a/crates/ra_ide/src/completion/complete_dot.rs b/crates/ra_ide/src/completion/complete_dot.rs
index 81e5037aa..f07611d88 100644
--- a/crates/ra_ide/src/completion/complete_dot.rs
+++ b/crates/ra_ide/src/completion/complete_dot.rs
@@ -402,6 +402,38 @@ mod tests {
     }
 
     #[test]
+    fn completes_trait_method_from_other_module() {
+        assert_debug_snapshot!(
+            do_ref_completion(
+                r"
+            struct A {}
+            mod m {
+                pub trait Trait { fn the_method(&self); }
+            }
+            use m::Trait;
+            impl Trait for A {}
+            fn foo(a: A) {
+               a.<|>
+            }
+            ",
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "the_method()",
+                source_range: [219; 219),
+                delete: [219; 219),
+                insert: "the_method()$0",
+                kind: Method,
+                lookup: "the_method",
+                detail: "fn the_method(&self)",
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
     fn test_no_non_self_method() {
         assert_debug_snapshot!(
         do_ref_completion(
diff --git a/crates/ra_ide/src/completion/complete_path.rs b/crates/ra_ide/src/completion/complete_path.rs
index d588ee364..3db17f15f 100644
--- a/crates/ra_ide/src/completion/complete_path.rs
+++ b/crates/ra_ide/src/completion/complete_path.rs
@@ -967,4 +967,74 @@ mod tests {
         ]
         "###);
     }
+
+    #[test]
+    fn function_mod_share_name() {
+        assert_debug_snapshot!(
+        do_reference_completion(
+                r"
+                fn foo() {
+                    self::m::<|>
+                }
+
+                mod m {
+                    pub mod z {}
+                    pub fn z() {}
+                }
+                ",
+        ),
+            @r###"
+        [
+            CompletionItem {
+                label: "z",
+                source_range: [57; 57),
+                delete: [57; 57),
+                insert: "z",
+                kind: Module,
+            },
+            CompletionItem {
+                label: "z()",
+                source_range: [57; 57),
+                delete: [57; 57),
+                insert: "z()$0",
+                kind: Function,
+                lookup: "z",
+                detail: "pub fn z()",
+            },
+        ]
+        "###
+        );
+    }
+
+    #[test]
+    fn completes_hashmap_new() {
+        assert_debug_snapshot!(
+            do_reference_completion(
+                r"
+                struct RandomState;
+                struct HashMap<K, V, S = RandomState> {}
+
+                impl<K, V> HashMap<K, V, RandomState> {
+                    pub fn new() -> HashMap<K, V, RandomState> { }
+                }
+                fn foo() {
+                    HashMap::<|>
+                }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "new()",
+                source_range: [292; 292),
+                delete: [292; 292),
+                insert: "new()$0",
+                kind: Function,
+                lookup: "new",
+                detail: "pub fn new() -> HashMap<K, V, RandomState>",
+            },
+        ]
+        "###
+        );
+    }
 }
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index a4e9aefe2..253848602 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -1,6 +1,6 @@
 //! This modules takes care of rendering various definitions as completion items.
 
-use hir::{db::HirDatabase, Docs, HasAttrs, HasSource, HirDisplay, ScopeDef, StructKind, Type};
+use hir::{Docs, HasAttrs, HasSource, HirDisplay, ScopeDef, StructKind, Type};
 use join_to_string::join;
 use ra_syntax::ast::NameOwner;
 use test_utils::tested_by;
@@ -9,7 +9,10 @@ use crate::completion::{
     CompletionContext, CompletionItem, CompletionItemKind, CompletionKind, Completions,
 };
 
-use crate::display::{const_label, macro_label, type_label, FunctionSignature};
+use crate::{
+    display::{const_label, macro_label, type_label, FunctionSignature},
+    RootDatabase,
+};
 
 impl Completions {
     pub(crate) fn add_field(
@@ -273,8 +276,10 @@ impl Completions {
     pub(crate) fn add_enum_variant(&mut self, ctx: &CompletionContext, variant: hir::EnumVariant) {
         let is_deprecated = is_deprecated(variant, ctx.db);
         let name = variant.name(ctx.db);
-        let detail_types =
-            variant.fields(ctx.db).into_iter().map(|field| (field.name(ctx.db), field.ty(ctx.db)));
+        let detail_types = variant
+            .fields(ctx.db)
+            .into_iter()
+            .map(|field| (field.name(ctx.db), field.signature_ty(ctx.db)));
         let detail = match variant.kind(ctx.db) {
             StructKind::Tuple | StructKind::Unit => {
                 join(detail_types.map(|(_, t)| t.display(ctx.db).to_string()))
@@ -298,7 +303,7 @@ impl Completions {
     }
 }
 
-fn is_deprecated(node: impl HasAttrs, db: &impl HirDatabase) -> bool {
+fn is_deprecated(node: impl HasAttrs, db: &RootDatabase) -> bool {
     node.attrs(db).by_key("deprecated").exists()
 }
 
diff --git a/crates/ra_ide/src/display.rs b/crates/ra_ide/src/display.rs
index eaeaaa2b4..c395057a7 100644
--- a/crates/ra_ide/src/display.rs
+++ b/crates/ra_ide/src/display.rs
@@ -6,6 +6,8 @@ mod navigation_target;
 mod structure;
 mod short_label;
 
+use std::fmt::{Display, Write};
+
 use ra_syntax::{
     ast::{self, AstNode, AttrsOwner, NameOwner, TypeParamsOwner},
     SyntaxKind::{ATTR, COMMENT},
@@ -67,24 +69,27 @@ pub(crate) fn macro_label(node: &ast::MacroCall) -> String {
     format!("{}macro_rules! {}", vis, name)
 }
 
-pub(crate) fn rust_code_markup<CODE: AsRef<str>>(val: CODE) -> String {
-    rust_code_markup_with_doc::<_, &str>(val, None, None)
+pub(crate) fn rust_code_markup(code: &impl Display) -> String {
+    rust_code_markup_with_doc(code, None, None)
 }
 
-pub(crate) fn rust_code_markup_with_doc<CODE, DOC>(
-    val: CODE,
-    doc: Option<DOC>,
-    mod_path: Option<String>,
-) -> String
-where
-    CODE: AsRef<str>,
-    DOC: AsRef<str>,
-{
-    let mod_path =
-        mod_path.filter(|path| !path.is_empty()).map(|path| path + "\n").unwrap_or_default();
+pub(crate) fn rust_code_markup_with_doc(
+    code: &impl Display,
+    doc: Option<&str>,
+    mod_path: Option<&str>,
+) -> String {
+    let mut markup = "```rust\n".to_owned();
+
+    if let Some(mod_path) = mod_path {
+        if !mod_path.is_empty() {
+            write!(markup, "{}\n", mod_path).unwrap();
+        }
+    }
+    write!(markup, "{}\n```", code).unwrap();
+
     if let Some(doc) = doc {
-        format!("```rust\n{}{}\n```\n\n{}", mod_path, val.as_ref(), doc.as_ref())
-    } else {
-        format!("```rust\n{}{}\n```", mod_path, val.as_ref())
+        write!(markup, "\n\n{}", doc).unwrap();
     }
+
+    markup
 }
diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index 2c4c932de..ec1bbd5a0 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -64,7 +64,7 @@ impl FunctionSignature {
             .fields(db)
             .into_iter()
             .map(|field: hir::StructField| {
-                let ty = field.ty(db);
+                let ty = field.signature_ty(db);
                 format!("{}", ty.display(db))
             })
             .collect();
@@ -102,7 +102,7 @@ impl FunctionSignature {
             .into_iter()
             .map(|field: hir::StructField| {
                 let name = field.name(db);
-                let ty = field.ty(db);
+                let ty = field.signature_ty(db);
                 format!("{}: {}", name, ty.display(db))
             })
             .collect();
diff --git a/crates/ra_ide/src/goto_definition.rs b/crates/ra_ide/src/goto_definition.rs
index a55a13ffc..a7be92ce3 100644
--- a/crates/ra_ide/src/goto_definition.rs
+++ b/crates/ra_ide/src/goto_definition.rs
@@ -788,6 +788,21 @@ mod tests {
     }
 
     #[test]
+    fn goto_def_in_local_macro() {
+        check_goto(
+            "
+            //- /lib.rs            
+            fn bar() {
+                macro_rules! foo { () => { () } }
+                <|>foo!();
+            }
+            ",
+            "foo MACRO_CALL FileId(1) [15; 48) [28; 31)",
+            "macro_rules! foo { () => { () } }|foo",
+        );
+    }
+
+    #[test]
     fn goto_def_for_field_init_shorthand() {
         covers!(ra_ide_db::goto_def_for_field_init_shorthand);
         check_goto(
diff --git a/crates/ra_ide/src/hover.rs b/crates/ra_ide/src/hover.rs
index 0bbba4855..5b3760c18 100644
--- a/crates/ra_ide/src/hover.rs
+++ b/crates/ra_ide/src/hover.rs
@@ -1,4 +1,5 @@
-//! FIXME: write short doc here
+//! Logic for computing info that is displayed when the user hovers over any
+//! source code items (e.g. function call, struct field, variable symbol...)
 
 use hir::{
     Adt, AsAssocItem, AssocItemContainer, FieldSource, HasSource, HirDisplay, ModuleDef,
@@ -24,35 +25,20 @@ use itertools::Itertools;
 use std::iter::once;
 
 /// Contains the results when hovering over an item
-#[derive(Debug, Clone)]
+#[derive(Debug, Default)]
 pub struct HoverResult {
     results: Vec<String>,
-    exact: bool,
-}
-
-impl Default for HoverResult {
-    fn default() -> Self {
-        HoverResult::new()
-    }
 }
 
 impl HoverResult {
     pub fn new() -> HoverResult {
-        HoverResult {
-            results: Vec::new(),
-            // We assume exact by default
-            exact: true,
-        }
+        Self::default()
     }
 
     pub fn extend(&mut self, item: Option<String>) {
         self.results.extend(item);
     }
 
-    pub fn is_exact(&self) -> bool {
-        self.exact
-    }
-
     pub fn is_empty(&self) -> bool {
         self.results.is_empty()
     }
@@ -72,20 +58,7 @@ impl HoverResult {
     /// Returns the results converted into markup
     /// for displaying in a UI
     pub fn to_markup(&self) -> String {
-        let mut markup = if !self.exact {
-            let mut msg = String::from("Failed to exactly resolve the symbol. This is probably because rust_analyzer does not yet support traits.");
-            if !self.results.is_empty() {
-                msg.push_str("  \nThese items were found instead:");
-            }
-            msg.push_str("\n\n---\n");
-            msg
-        } else {
-            String::new()
-        };
-
-        markup.push_str(&self.results.join("\n\n---\n"));
-
-        markup
+        self.results.join("\n\n---\n")
     }
 }
 
@@ -94,10 +67,10 @@ fn hover_text(
     desc: Option<String>,
     mod_path: Option<String>,
 ) -> Option<String> {
-    match (desc, docs, mod_path) {
-        (Some(desc), docs, mod_path) => Some(rust_code_markup_with_doc(desc, docs, mod_path)),
-        (None, Some(docs), _) => Some(docs),
-        _ => None,
+    if let Some(desc) = desc {
+        Some(rust_code_markup_with_doc(&desc, docs.as_deref(), mod_path.as_deref()))
+    } else {
+        docs
     }
 }
 
@@ -121,7 +94,7 @@ fn definition_owner_name(db: &RootDatabase, def: &Definition) -> Option<String>
 
 fn determine_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
     let mod_path = def.module(db).map(|module| {
-        once(db.crate_graph()[module.krate().into()].display_name.clone())
+        once(db.crate_graph()[module.krate().into()].display_name.as_ref().map(ToString::to_string))
             .chain(
                 module
                     .path_to_root(db)
@@ -133,7 +106,7 @@ fn determine_mod_path(db: &RootDatabase, def: &Definition) -> Option<String> {
             .flatten()
             .join("::")
     });
-    mod_path
+    mod_path // FIXME: replace dashes with underscores in crate display name
 }
 
 fn hover_text_from_name_kind(db: &RootDatabase, def: Definition) -> Option<String> {
@@ -170,9 +143,7 @@ fn hover_text_from_name_kind(db: &RootDatabase, def: Definition) -> Option<Strin
             ModuleDef::TypeAlias(it) => from_def_source(db, it, mod_path),
             ModuleDef::BuiltinType(it) => Some(it.to_string()),
         },
-        Definition::Local(it) => {
-            Some(rust_code_markup(it.ty(db).display_truncated(db, None).to_string()))
-        }
+        Definition::Local(it) => Some(rust_code_markup(&it.ty(db).display_truncated(db, None))),
         Definition::TypeParam(_) | Definition::SelfType(_) => {
             // FIXME: Hover for generic param
             None
@@ -237,7 +208,7 @@ pub(crate) fn hover(db: &RootDatabase, position: FilePosition) -> Option<RangeIn
         }
     }?;
 
-    res.extend(Some(rust_code_markup(ty.display_truncated(db, None).to_string())));
+    res.extend(Some(rust_code_markup(&ty.display_truncated(db, None))));
     let range = sema.original_range(&node).range;
     Some(RangeInfo::new(range, res))
 }
@@ -595,7 +566,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("wrapper::Thing\nfn new() -> Thing"));
-        assert_eq!(hover.info.is_exact(), true);
     }
 
     #[test]
@@ -618,7 +588,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("const C: u32"));
-        assert_eq!(hover.info.is_exact(), true);
     }
 
     #[test]
@@ -635,7 +604,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("Thing"));
-        assert_eq!(hover.info.is_exact(), true);
 
         /* FIXME: revive these tests
                 let (analysis, position) = single_file_with_position(
@@ -651,7 +619,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
 
                 let hover = analysis.hover(position).unwrap().unwrap();
                 assert_eq!(trim_markup_opt(hover.info.first()), Some("Thing"));
-                assert_eq!(hover.info.is_exact(), true);
 
                 let (analysis, position) = single_file_with_position(
                     "
@@ -665,7 +632,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
                 );
                 let hover = analysis.hover(position).unwrap().unwrap();
                 assert_eq!(trim_markup_opt(hover.info.first()), Some("enum Thing"));
-                assert_eq!(hover.info.is_exact(), true);
 
                 let (analysis, position) = single_file_with_position(
                     "
@@ -678,7 +644,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
                 );
                 let hover = analysis.hover(position).unwrap().unwrap();
                 assert_eq!(trim_markup_opt(hover.info.first()), Some("enum Thing"));
-                assert_eq!(hover.info.is_exact(), true);
         */
     }
 
@@ -696,7 +661,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
-        assert_eq!(hover.info.is_exact(), true);
     }
 
     #[test]
@@ -714,7 +678,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("macro_rules! foo"));
-        assert_eq!(hover.info.is_exact(), true);
     }
 
     #[test]
@@ -726,7 +689,6 @@ fn func(foo: i32) { if true { <|>foo; }; }
         );
         let hover = analysis.hover(position).unwrap().unwrap();
         assert_eq!(trim_markup_opt(hover.info.first()), Some("i32"));
-        assert_eq!(hover.info.is_exact(), true);
     }
 
     #[test]
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index e9af80b6c..5ab06c6cf 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -473,9 +473,10 @@ impl Analysis {
     pub fn structural_search_replace(
         &self,
         query: &str,
+        parse_only: bool,
     ) -> Cancelable<Result<SourceChange, SsrError>> {
         self.with_db(|db| {
-            let edits = ssr::parse_search_replace(query, db)?;
+            let edits = ssr::parse_search_replace(query, parse_only, db)?;
             Ok(SourceChange::source_file_edits("ssr", edits))
         })
     }
diff --git a/crates/ra_ide/src/mock_analysis.rs b/crates/ra_ide/src/mock_analysis.rs
index 25816cf6f..2cf77a31f 100644
--- a/crates/ra_ide/src/mock_analysis.rs
+++ b/crates/ra_ide/src/mock_analysis.rs
@@ -109,7 +109,7 @@ impl MockAnalysis {
                 let other_crate = crate_graph.add_crate_root(
                     file_id,
                     Edition2018,
-                    Some(crate_name.to_owned()),
+                    Some(CrateName::new(crate_name).unwrap()),
                     cfg_options,
                     Env::default(),
                     Default::default(),
diff --git a/crates/ra_ide/src/ssr.rs b/crates/ra_ide/src/ssr.rs
index c011a2e74..1c9710a5d 100644
--- a/crates/ra_ide/src/ssr.rs
+++ b/crates/ra_ide/src/ssr.rs
@@ -1,8 +1,10 @@
 //!  structural search replace
 
 use crate::source_change::SourceFileEdit;
+use ra_db::{SourceDatabase, SourceDatabaseExt};
+use ra_ide_db::symbol_index::SymbolsDatabase;
 use ra_ide_db::RootDatabase;
-use ra_syntax::ast::make::expr_from_text;
+use ra_syntax::ast::make::try_expr_from_text;
 use ra_syntax::ast::{AstToken, Comment};
 use ra_syntax::{AstNode, SyntaxElement, SyntaxNode};
 use ra_text_edit::{TextEdit, TextEditBuilder};
@@ -10,9 +12,6 @@ use rustc_hash::FxHashMap;
 use std::collections::HashMap;
 use std::str::FromStr;
 
-pub use ra_db::{SourceDatabase, SourceDatabaseExt};
-use ra_ide_db::symbol_index::SymbolsDatabase;
-
 #[derive(Debug, PartialEq)]
 pub struct SsrError(String);
 
@@ -26,14 +25,17 @@ impl std::error::Error for SsrError {}
 
 pub fn parse_search_replace(
     query: &str,
+    parse_only: bool,
     db: &RootDatabase,
 ) -> Result<Vec<SourceFileEdit>, SsrError> {
     let mut edits = vec![];
     let query: SsrQuery = query.parse()?;
+    if parse_only {
+        return Ok(edits);
+    }
     for &root in db.local_roots().iter() {
         let sr = db.source_root(root);
         for file_id in sr.walk() {
-            dbg!(db.file_relative_path(file_id));
             let matches = find(&query.pattern, db.parse(file_id).tree().syntax());
             if !matches.matches.is_empty() {
                 edits.push(SourceFileEdit { file_id, edit: replace(&matches, &query.template) });
@@ -106,7 +108,10 @@ impl FromStr for SsrQuery {
             template = replace_in_template(template, var, new_var);
         }
 
-        let template = expr_from_text(&template).syntax().clone();
+        let template = try_expr_from_text(&template)
+            .ok_or(SsrError("Template is not an expression".into()))?
+            .syntax()
+            .clone();
         let mut placeholders = FxHashMap::default();
 
         traverse(&template, &mut |n| {
@@ -118,7 +123,13 @@ impl FromStr for SsrQuery {
             }
         });
 
-        let pattern = SsrPattern { pattern: expr_from_text(&pattern).syntax().clone(), vars };
+        let pattern = SsrPattern {
+            pattern: try_expr_from_text(&pattern)
+                .ok_or(SsrError("Pattern is not an expression".into()))?
+                .syntax()
+                .clone(),
+            vars,
+        };
         let template = SsrTemplate { template, placeholders };
         Ok(SsrQuery { pattern, template })
     }
@@ -284,7 +295,6 @@ mod tests {
         assert_eq!(result.pattern.vars[0].0, "__search_pattern_a");
         assert_eq!(result.pattern.vars[1].0, "__search_pattern_b");
         assert_eq!(&result.template.template.text(), "bar(__search_pattern_b, __search_pattern_a)");
-        dbg!(result.template.placeholders);
     }
 
     #[test]
@@ -335,6 +345,16 @@ mod tests {
     }
 
     #[test]
+    fn parser_invlid_pattern() {
+        assert_eq!(parse_error_text(" ==>> ()"), "Parse error: Pattern is not an expression");
+    }
+
+    #[test]
+    fn parser_invlid_template() {
+        assert_eq!(parse_error_text("() ==>> )"), "Parse error: Template is not an expression");
+    }
+
+    #[test]
     fn parse_match_replace() {
         let query: SsrQuery = "foo($x:expr) ==>> bar($x)".parse().unwrap();
         let input = "fn main() { foo(1+2); }";
diff --git a/crates/ra_ide/src/typing.rs b/crates/ra_ide/src/typing.rs
index 53c65f8bc..cb2cd2479 100644
--- a/crates/ra_ide/src/typing.rs
+++ b/crates/ra_ide/src/typing.rs
@@ -213,14 +213,14 @@ fn foo() {
         type_char(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                 <|>
             }
             ",
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     .
             }
             ",
@@ -228,8 +228,8 @@ fn foo() {
         type_char_noop(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     <|>
             }
             ",
@@ -241,14 +241,14 @@ fn foo() {
         type_char(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                 <|>;
             }
             ",
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     .;
             }
             ",
@@ -256,8 +256,8 @@ fn foo() {
         type_char_noop(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     <|>;
             }
             ",
@@ -269,15 +269,15 @@ fn foo() {
         type_char(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     .first()
                 <|>
             }
             ",
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     .first()
                     .
             }
@@ -286,8 +286,8 @@ fn foo() {
         type_char_noop(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
-                self.child_impl(db, name)
+            fn main() {
+                xs.foo()
                     .first()
                     <|>
             }
@@ -334,7 +334,7 @@ fn foo() {
         type_char_noop(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
+            fn main() {
                 <|>
             }
             ",
@@ -342,7 +342,7 @@ fn foo() {
         type_char_noop(
             '.',
             r"
-            pub fn child(&self, db: &impl HirDatabase, name: &Name) -> Cancelable<Option<Module>> {
+            fn main() {
             <|>
             }
             ",
diff --git a/crates/ra_parser/src/grammar/params.rs b/crates/ra_parser/src/grammar/params.rs
index 272661b1d..f0da173cc 100644
--- a/crates/ra_parser/src/grammar/params.rs
+++ b/crates/ra_parser/src/grammar/params.rs
@@ -56,21 +56,17 @@ fn list_(p: &mut Parser, flavor: Flavor) {
         // fn f(#[attr1] pat: Type) {}
         attributes::outer_attributes(p);
 
-        // test param_list_vararg
-        // extern "C" { fn printf(format: *const i8, ...) -> i32; }
-        match flavor {
-            FnDef | FnPointer if p.eat(T![...]) => break,
-            _ => (),
-        }
-
         if !p.at_ts(VALUE_PARAMETER_FIRST) {
             p.error("expected value parameter");
             break;
         }
-        value_parameter(p, flavor);
+        let param = value_parameter(p, flavor);
         if !p.at(ket) {
             p.expect(T![,]);
         }
+        if let Variadic(true) = param {
+            break;
+        }
     }
 
     p.expect(ket);
@@ -79,32 +75,25 @@ fn list_(p: &mut Parser, flavor: Flavor) {
 
 const VALUE_PARAMETER_FIRST: TokenSet = patterns::PATTERN_FIRST.union(types::TYPE_FIRST);
 
-fn value_parameter(p: &mut Parser, flavor: Flavor) {
+struct Variadic(bool);
+
+fn value_parameter(p: &mut Parser, flavor: Flavor) -> Variadic {
+    let mut res = Variadic(false);
     let m = p.start();
     match flavor {
-        // test trait_fn_placeholder_parameter
-        // trait Foo {
-        //     fn bar(_: u64, mut x: i32);
-        // }
-
-        // test trait_fn_patterns
-        // trait T {
-        //     fn f1((a, b): (usize, usize)) {}
-        //     fn f2(S { a, b }: S) {}
-        //     fn f3(NewType(a): NewType) {}
-        //     fn f4(&&a: &&usize) {}
-        // }
+        // test param_list_vararg
+        // extern "C" { fn printf(format: *const i8, ...) -> i32; }
+        Flavor::FnDef | Flavor::FnPointer if p.eat(T![...]) => res = Variadic(true),
 
-        // test fn_patterns
-        // impl U {
-        //     fn f1((a, b): (usize, usize)) {}
-        //     fn f2(S { a, b }: S) {}
-        //     fn f3(NewType(a): NewType) {}
-        //     fn f4(&&a: &&usize) {}
-        // }
+        // test fn_def_param
+        // fn foo((x, y): (i32, i32)) {}
         Flavor::FnDef => {
             patterns::pattern(p);
-            types::ascription(p);
+            if variadic_param(p) {
+                res = Variadic(true)
+            } else {
+                types::ascription(p);
+            }
         }
         // test value_parameters_no_patterns
         // type F = Box<Fn(i32, &i32, &i32, ())>;
@@ -120,7 +109,11 @@ fn value_parameter(p: &mut Parser, flavor: Flavor) {
         Flavor::FnPointer => {
             if (p.at(IDENT) || p.at(UNDERSCORE)) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
                 patterns::pattern_single(p);
-                types::ascription(p);
+                if variadic_param(p) {
+                    res = Variadic(true)
+                } else {
+                    types::ascription(p);
+                }
             } else {
                 types::type_(p);
             }
@@ -137,6 +130,17 @@ fn value_parameter(p: &mut Parser, flavor: Flavor) {
         }
     }
     m.complete(p, PARAM);
+    res
+}
+
+fn variadic_param(p: &mut Parser) -> bool {
+    if p.at(T![:]) && p.nth_at(1, T![...]) {
+        p.bump(T![:]);
+        p.bump(T![...]);
+        true
+    } else {
+        false
+    }
 }
 
 // test self_param
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index a6274709d..897874813 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -245,7 +245,10 @@ impl ProjectWorkspace {
                         let crate_id = crate_graph.add_crate_root(
                             file_id,
                             Edition::Edition2018,
-                            Some(krate.name(&sysroot).to_string()),
+                            Some(
+                                CrateName::new(krate.name(&sysroot))
+                                    .expect("Sysroot crate names should not contain dashes"),
+                            ),
                             cfg_options,
                             env,
                             extern_source,
@@ -296,7 +299,7 @@ impl ProjectWorkspace {
                             let crate_id = crate_graph.add_crate_root(
                                 file_id,
                                 edition,
-                                Some(pkg.name(&cargo).to_string()),
+                                Some(CrateName::normalize_dashes(pkg.name(&cargo))),
                                 cfg_options,
                                 env,
                                 extern_source,
diff --git a/crates/ra_syntax/src/ast/make.rs b/crates/ra_syntax/src/ast/make.rs
index ae8829807..9f6f1cc53 100644
--- a/crates/ra_syntax/src/ast/make.rs
+++ b/crates/ra_syntax/src/ast/make.rs
@@ -112,10 +112,14 @@ pub fn expr_prefix(op: SyntaxKind, expr: ast::Expr) -> ast::Expr {
     let token = token(op);
     expr_from_text(&format!("{}{}", token, expr.syntax()))
 }
-pub fn expr_from_text(text: &str) -> ast::Expr {
+fn expr_from_text(text: &str) -> ast::Expr {
     ast_from_text(&format!("const C: () = {};", text))
 }
 
+pub fn try_expr_from_text(text: &str) -> Option<ast::Expr> {
+    try_ast_from_text(&format!("const C: () = {};", text))
+}
+
 pub fn bind_pat(name: ast::Name) -> ast::BindPat {
     return from_text(name.text());
 
@@ -239,6 +243,16 @@ fn ast_from_text<N: AstNode>(text: &str) -> N {
     node
 }
 
+fn try_ast_from_text<N: AstNode>(text: &str) -> Option<N> {
+    let parse = SourceFile::parse(text);
+    let node = parse.tree().syntax().descendants().find_map(N::cast)?;
+    let node = node.syntax().clone();
+    let node = unroot(node);
+    let node = N::cast(node).unwrap();
+    assert_eq!(node.syntax().text_range().start(), 0.into());
+    Some(node)
+}
+
 fn unroot(n: SyntaxNode) -> SyntaxNode {
     SyntaxNode::new_root(n.green().clone())
 }
diff --git a/crates/ra_syntax/src/tests.rs b/crates/ra_syntax/src/tests.rs
index d331d541e..6a8cb6bb5 100644
--- a/crates/ra_syntax/src/tests.rs
+++ b/crates/ra_syntax/src/tests.rs
@@ -34,6 +34,7 @@ fn main() {
     "##;
 
     let parse = SourceFile::parse(code);
+    // eprintln!("{:#?}", parse.syntax_node());
     assert!(parse.ok().is_ok());
 }
 
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0032_fn_pointer_type.txt b/crates/ra_syntax/test_data/parser/inline/ok/0032_fn_pointer_type.txt
index a0a8aea76..4c17f0db8 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0032_fn_pointer_type.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0032_fn_pointer_type.txt
@@ -81,7 +81,8 @@ SOURCE_FILE@[0; 113)
         WHITESPACE@[97; 98) " "
         COMMA@[98; 99) ","
         WHITESPACE@[99; 100) " "
-        DOTDOTDOT@[100; 103) "..."
+        PARAM@[100; 103)
+          DOTDOTDOT@[100; 103) "..."
         WHITESPACE@[103; 104) " "
         R_PAREN@[104; 105) ")"
       WHITESPACE@[105; 106) " "
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.rs b/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.rs
deleted file mode 100644
index 472cb8803..000000000
--- a/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-trait Foo {
-    fn bar(_: u64, mut x: i32);
-}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.txt b/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.txt
deleted file mode 100644
index 158236c5a..000000000
--- a/crates/ra_syntax/test_data/parser/inline/ok/0116_trait_fn_placeholder_parameter.txt
+++ /dev/null
@@ -1,47 +0,0 @@
-SOURCE_FILE@[0; 46)
-  TRAIT_DEF@[0; 45)
-    TRAIT_KW@[0; 5) "trait"
-    WHITESPACE@[5; 6) " "
-    NAME@[6; 9)
-      IDENT@[6; 9) "Foo"
-    WHITESPACE@[9; 10) " "
-    ITEM_LIST@[10; 45)
-      L_CURLY@[10; 11) "{"
-      WHITESPACE@[11; 16) "\n    "
-      FN_DEF@[16; 43)
-        FN_KW@[16; 18) "fn"
-        WHITESPACE@[18; 19) " "
-        NAME@[19; 22)
-          IDENT@[19; 22) "bar"
-        PARAM_LIST@[22; 42)
-          L_PAREN@[22; 23) "("
-          PARAM@[23; 29)
-            PLACEHOLDER_PAT@[23; 24)
-              UNDERSCORE@[23; 24) "_"
-            COLON@[24; 25) ":"
-            WHITESPACE@[25; 26) " "
-            PATH_TYPE@[26; 29)
-              PATH@[26; 29)
-                PATH_SEGMENT@[26; 29)
-                  NAME_REF@[26; 29)
-                    IDENT@[26; 29) "u64"
-          COMMA@[29; 30) ","
-          WHITESPACE@[30; 31) " "
-          PARAM@[31; 41)
-            BIND_PAT@[31; 36)
-              MUT_KW@[31; 34) "mut"
-              WHITESPACE@[34; 35) " "
-              NAME@[35; 36)
-                IDENT@[35; 36) "x"
-            COLON@[36; 37) ":"
-            WHITESPACE@[37; 38) " "
-            PATH_TYPE@[38; 41)
-              PATH@[38; 41)
-                PATH_SEGMENT@[38; 41)
-                  NAME_REF@[38; 41)
-                    IDENT@[38; 41) "i32"
-          R_PAREN@[41; 42) ")"
-        SEMI@[42; 43) ";"
-      WHITESPACE@[43; 44) "\n"
-      R_CURLY@[44; 45) "}"
-  WHITESPACE@[45; 46) "\n"
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0123_param_list_vararg.txt b/crates/ra_syntax/test_data/parser/inline/ok/0123_param_list_vararg.txt
index 836e8e55b..6c3b17868 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0123_param_list_vararg.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0123_param_list_vararg.txt
@@ -32,7 +32,8 @@ SOURCE_FILE@[0; 57)
                       IDENT@[38; 40) "i8"
           COMMA@[40; 41) ","
           WHITESPACE@[41; 42) " "
-          DOTDOTDOT@[42; 45) "..."
+          PARAM@[42; 45)
+            DOTDOTDOT@[42; 45) "..."
           R_PAREN@[45; 46) ")"
         WHITESPACE@[46; 47) " "
         RET_TYPE@[47; 53)
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.rs b/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.rs
new file mode 100644
index 000000000..7b277c16b
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.rs
@@ -0,0 +1 @@
+fn foo((x, y): (i32, i32)) {}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.txt b/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.txt
new file mode 100644
index 000000000..103e254a6
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0156_fn_def_param.txt
@@ -0,0 +1,44 @@
+SOURCE_FILE@[0; 30)
+  FN_DEF@[0; 29)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 6)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 26)
+      L_PAREN@[6; 7) "("
+      PARAM@[7; 25)
+        TUPLE_PAT@[7; 13)
+          L_PAREN@[7; 8) "("
+          BIND_PAT@[8; 9)
+            NAME@[8; 9)
+              IDENT@[8; 9) "x"
+          COMMA@[9; 10) ","
+          WHITESPACE@[10; 11) " "
+          BIND_PAT@[11; 12)
+            NAME@[11; 12)
+              IDENT@[11; 12) "y"
+          R_PAREN@[12; 13) ")"
+        COLON@[13; 14) ":"
+        WHITESPACE@[14; 15) " "
+        TUPLE_TYPE@[15; 25)
+          L_PAREN@[15; 16) "("
+          PATH_TYPE@[16; 19)
+            PATH@[16; 19)
+              PATH_SEGMENT@[16; 19)
+                NAME_REF@[16; 19)
+                  IDENT@[16; 19) "i32"
+          COMMA@[19; 20) ","
+          WHITESPACE@[20; 21) " "
+          PATH_TYPE@[21; 24)
+            PATH@[21; 24)
+              PATH_SEGMENT@[21; 24)
+                NAME_REF@[21; 24)
+                  IDENT@[21; 24) "i32"
+          R_PAREN@[24; 25) ")"
+      R_PAREN@[25; 26) ")"
+    WHITESPACE@[26; 27) " "
+    BLOCK_EXPR@[27; 29)
+      BLOCK@[27; 29)
+        L_CURLY@[27; 28) "{"
+        R_CURLY@[28; 29) "}"
+  WHITESPACE@[29; 30) "\n"
diff --git a/crates/ra_syntax/test_data/parser/ok/0051_parameter_attrs.txt b/crates/ra_syntax/test_data/parser/ok/0051_parameter_attrs.txt
index 719c99c17..254eafc36 100644
--- a/crates/ra_syntax/test_data/parser/ok/0051_parameter_attrs.txt
+++ b/crates/ra_syntax/test_data/parser/ok/0051_parameter_attrs.txt
@@ -118,7 +118,8 @@ SOURCE_FILE@[0; 519)
                   IDENT@[108; 112) "attr"
             R_BRACK@[112; 113) "]"
           WHITESPACE@[113; 114) " "
-          DOTDOTDOT@[114; 117) "..."
+          PARAM@[114; 117)
+            DOTDOTDOT@[114; 117) "..."
           R_PAREN@[117; 118) ")"
         WHITESPACE@[118; 119) " "
         RET_TYPE@[119; 125)
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0153_trait_fn_patterns.rs b/crates/ra_syntax/test_data/parser/ok/0063_trait_fn_patterns.rs
index a94bf378a..3b666af8e 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0153_trait_fn_patterns.rs
+++ b/crates/ra_syntax/test_data/parser/ok/0063_trait_fn_patterns.rs
@@ -3,4 +3,5 @@ trait T {
     fn f2(S { a, b }: S) {}
     fn f3(NewType(a): NewType) {}
     fn f4(&&a: &&usize) {}
+    fn bar(_: u64, mut x: i32);
 }
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0153_trait_fn_patterns.txt b/crates/ra_syntax/test_data/parser/ok/0063_trait_fn_patterns.txt
index b22df8dbe..eb2e3a503 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0153_trait_fn_patterns.txt
+++ b/crates/ra_syntax/test_data/parser/ok/0063_trait_fn_patterns.txt
@@ -1,11 +1,11 @@
-SOURCE_FILE@[0; 138)
-  TRAIT_DEF@[0; 137)
+SOURCE_FILE@[0; 170)
+  TRAIT_DEF@[0; 169)
     TRAIT_KW@[0; 5) "trait"
     WHITESPACE@[5; 6) " "
     NAME@[6; 7)
       IDENT@[6; 7) "T"
     WHITESPACE@[7; 8) " "
-    ITEM_LIST@[8; 137)
+    ITEM_LIST@[8; 169)
       L_CURLY@[8; 9) "{"
       WHITESPACE@[9; 14) "\n    "
       FN_DEF@[14; 46)
@@ -156,6 +156,41 @@ SOURCE_FILE@[0; 138)
           BLOCK@[133; 135)
             L_CURLY@[133; 134) "{"
             R_CURLY@[134; 135) "}"
-      WHITESPACE@[135; 136) "\n"
-      R_CURLY@[136; 137) "}"
-  WHITESPACE@[137; 138) "\n"
+      WHITESPACE@[135; 140) "\n    "
+      FN_DEF@[140; 167)
+        FN_KW@[140; 142) "fn"
+        WHITESPACE@[142; 143) " "
+        NAME@[143; 146)
+          IDENT@[143; 146) "bar"
+        PARAM_LIST@[146; 166)
+          L_PAREN@[146; 147) "("
+          PARAM@[147; 153)
+            PLACEHOLDER_PAT@[147; 148)
+              UNDERSCORE@[147; 148) "_"
+            COLON@[148; 149) ":"
+            WHITESPACE@[149; 150) " "
+            PATH_TYPE@[150; 153)
+              PATH@[150; 153)
+                PATH_SEGMENT@[150; 153)
+                  NAME_REF@[150; 153)
+                    IDENT@[150; 153) "u64"
+          COMMA@[153; 154) ","
+          WHITESPACE@[154; 155) " "
+          PARAM@[155; 165)
+            BIND_PAT@[155; 160)
+              MUT_KW@[155; 158) "mut"
+              WHITESPACE@[158; 159) " "
+              NAME@[159; 160)
+                IDENT@[159; 160) "x"
+            COLON@[160; 161) ":"
+            WHITESPACE@[161; 162) " "
+            PATH_TYPE@[162; 165)
+              PATH@[162; 165)
+                PATH_SEGMENT@[162; 165)
+                  NAME_REF@[162; 165)
+                    IDENT@[162; 165) "i32"
+          R_PAREN@[165; 166) ")"
+        SEMI@[166; 167) ";"
+      WHITESPACE@[167; 168) "\n"
+      R_CURLY@[168; 169) "}"
+  WHITESPACE@[169; 170) "\n"
diff --git a/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.rs b/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.rs
new file mode 100644
index 000000000..a16afbaf3
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.rs
@@ -0,0 +1,5 @@
+extern "C" {
+    fn a(_: *mut u8, ...,);
+    fn b(_: *mut u8, _: ...);
+    fn c(_: *mut u8, #[cfg(never)] [w, t, f]: ...,);
+}
diff --git a/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.txt b/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.txt
new file mode 100644
index 000000000..186f03626
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/ok/0063_variadic_fun.txt
@@ -0,0 +1,133 @@
+SOURCE_FILE@[0; 126)
+  EXTERN_BLOCK@[0; 125)
+    ABI@[0; 10)
+      EXTERN_KW@[0; 6) "extern"
+      WHITESPACE@[6; 7) " "
+      STRING@[7; 10) "\"C\""
+    WHITESPACE@[10; 11) " "
+    EXTERN_ITEM_LIST@[11; 125)
+      L_CURLY@[11; 12) "{"
+      WHITESPACE@[12; 17) "\n    "
+      FN_DEF@[17; 40)
+        FN_KW@[17; 19) "fn"
+        WHITESPACE@[19; 20) " "
+        NAME@[20; 21)
+          IDENT@[20; 21) "a"
+        PARAM_LIST@[21; 39)
+          L_PAREN@[21; 22) "("
+          PARAM@[22; 32)
+            PLACEHOLDER_PAT@[22; 23)
+              UNDERSCORE@[22; 23) "_"
+            COLON@[23; 24) ":"
+            WHITESPACE@[24; 25) " "
+            POINTER_TYPE@[25; 32)
+              STAR@[25; 26) "*"
+              MUT_KW@[26; 29) "mut"
+              WHITESPACE@[29; 30) " "
+              PATH_TYPE@[30; 32)
+                PATH@[30; 32)
+                  PATH_SEGMENT@[30; 32)
+                    NAME_REF@[30; 32)
+                      IDENT@[30; 32) "u8"
+          COMMA@[32; 33) ","
+          WHITESPACE@[33; 34) " "
+          PARAM@[34; 37)
+            DOTDOTDOT@[34; 37) "..."
+          COMMA@[37; 38) ","
+          R_PAREN@[38; 39) ")"
+        SEMI@[39; 40) ";"
+      WHITESPACE@[40; 45) "\n    "
+      FN_DEF@[45; 70)
+        FN_KW@[45; 47) "fn"
+        WHITESPACE@[47; 48) " "
+        NAME@[48; 49)
+          IDENT@[48; 49) "b"
+        PARAM_LIST@[49; 69)
+          L_PAREN@[49; 50) "("
+          PARAM@[50; 60)
+            PLACEHOLDER_PAT@[50; 51)
+              UNDERSCORE@[50; 51) "_"
+            COLON@[51; 52) ":"
+            WHITESPACE@[52; 53) " "
+            POINTER_TYPE@[53; 60)
+              STAR@[53; 54) "*"
+              MUT_KW@[54; 57) "mut"
+              WHITESPACE@[57; 58) " "
+              PATH_TYPE@[58; 60)
+                PATH@[58; 60)
+                  PATH_SEGMENT@[58; 60)
+                    NAME_REF@[58; 60)
+                      IDENT@[58; 60) "u8"
+          COMMA@[60; 61) ","
+          WHITESPACE@[61; 62) " "
+          PARAM@[62; 68)
+            PLACEHOLDER_PAT@[62; 63)
+              UNDERSCORE@[62; 63) "_"
+            COLON@[63; 64) ":"
+            WHITESPACE@[64; 65) " "
+            DOTDOTDOT@[65; 68) "..."
+          R_PAREN@[68; 69) ")"
+        SEMI@[69; 70) ";"
+      WHITESPACE@[70; 75) "\n    "
+      FN_DEF@[75; 123)
+        FN_KW@[75; 77) "fn"
+        WHITESPACE@[77; 78) " "
+        NAME@[78; 79)
+          IDENT@[78; 79) "c"
+        PARAM_LIST@[79; 122)
+          L_PAREN@[79; 80) "("
+          PARAM@[80; 90)
+            PLACEHOLDER_PAT@[80; 81)
+              UNDERSCORE@[80; 81) "_"
+            COLON@[81; 82) ":"
+            WHITESPACE@[82; 83) " "
+            POINTER_TYPE@[83; 90)
+              STAR@[83; 84) "*"
+              MUT_KW@[84; 87) "mut"
+              WHITESPACE@[87; 88) " "
+              PATH_TYPE@[88; 90)
+                PATH@[88; 90)
+                  PATH_SEGMENT@[88; 90)
+                    NAME_REF@[88; 90)
+                      IDENT@[88; 90) "u8"
+          COMMA@[90; 91) ","
+          WHITESPACE@[91; 92) " "
+          ATTR@[92; 105)
+            POUND@[92; 93) "#"
+            L_BRACK@[93; 94) "["
+            PATH@[94; 97)
+              PATH_SEGMENT@[94; 97)
+                NAME_REF@[94; 97)
+                  IDENT@[94; 97) "cfg"
+            TOKEN_TREE@[97; 104)
+              L_PAREN@[97; 98) "("
+              IDENT@[98; 103) "never"
+              R_PAREN@[103; 104) ")"
+            R_BRACK@[104; 105) "]"
+          WHITESPACE@[105; 106) " "
+          PARAM@[106; 120)
+            SLICE_PAT@[106; 115)
+              L_BRACK@[106; 107) "["
+              BIND_PAT@[107; 108)
+                NAME@[107; 108)
+                  IDENT@[107; 108) "w"
+              COMMA@[108; 109) ","
+              WHITESPACE@[109; 110) " "
+              BIND_PAT@[110; 111)
+                NAME@[110; 111)
+                  IDENT@[110; 111) "t"
+              COMMA@[111; 112) ","
+              WHITESPACE@[112; 113) " "
+              BIND_PAT@[113; 114)
+                NAME@[113; 114)
+                  IDENT@[113; 114) "f"
+              R_BRACK@[114; 115) "]"
+            COLON@[115; 116) ":"
+            WHITESPACE@[116; 117) " "
+            DOTDOTDOT@[117; 120) "..."
+          COMMA@[120; 121) ","
+          R_PAREN@[121; 122) ")"
+        SEMI@[122; 123) ";"
+      WHITESPACE@[123; 124) "\n"
+      R_CURLY@[124; 125) "}"
+  WHITESPACE@[125; 126) "\n"
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.rs b/crates/ra_syntax/test_data/parser/ok/0064_impl_fn_params.rs
index b49e872d7..b49e872d7 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.rs
+++ b/crates/ra_syntax/test_data/parser/ok/0064_impl_fn_params.rs
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.txt b/crates/ra_syntax/test_data/parser/ok/0064_impl_fn_params.txt
index b30030de3..b30030de3 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0152_fn_patterns.txt
+++ b/crates/ra_syntax/test_data/parser/ok/0064_impl_fn_params.txt
diff --git a/crates/rust-analyzer/src/cargo_target_spec.rs b/crates/rust-analyzer/src/cargo_target_spec.rs
index 53751aafb..321861b16 100644
--- a/crates/rust-analyzer/src/cargo_target_spec.rs
+++ b/crates/rust-analyzer/src/cargo_target_spec.rs
@@ -19,50 +19,48 @@ impl CargoTargetSpec {
     pub(crate) fn runnable_args(
         spec: Option<CargoTargetSpec>,
         kind: &RunnableKind,
-    ) -> Result<Vec<String>> {
-        let mut res = Vec::new();
+    ) -> Result<(Vec<String>, Vec<String>)> {
+        let mut args = Vec::new();
+        let mut extra_args = Vec::new();
         match kind {
             RunnableKind::Test { test_id } => {
-                res.push("test".to_string());
+                args.push("test".to_string());
                 if let Some(spec) = spec {
-                    spec.push_to(&mut res);
+                    spec.push_to(&mut args);
                 }
-                res.push("--".to_string());
-                res.push(test_id.to_string());
+                extra_args.push(test_id.to_string());
                 if let TestId::Path(_) = test_id {
-                    res.push("--exact".to_string());
+                    extra_args.push("--exact".to_string());
                 }
-                res.push("--nocapture".to_string());
+                extra_args.push("--nocapture".to_string());
             }
             RunnableKind::TestMod { path } => {
-                res.push("test".to_string());
+                args.push("test".to_string());
                 if let Some(spec) = spec {
-                    spec.push_to(&mut res);
+                    spec.push_to(&mut args);
                 }
-                res.push("--".to_string());
-                res.push(path.to_string());
-                res.push("--nocapture".to_string());
+                extra_args.push(path.to_string());
+                extra_args.push("--nocapture".to_string());
             }
             RunnableKind::Bench { test_id } => {
-                res.push("bench".to_string());
+                args.push("bench".to_string());
                 if let Some(spec) = spec {
-                    spec.push_to(&mut res);
+                    spec.push_to(&mut args);
                 }
-                res.push("--".to_string());
-                res.push(test_id.to_string());
+                extra_args.push(test_id.to_string());
                 if let TestId::Path(_) = test_id {
-                    res.push("--exact".to_string());
+                    extra_args.push("--exact".to_string());
                 }
-                res.push("--nocapture".to_string());
+                extra_args.push("--nocapture".to_string());
             }
             RunnableKind::Bin => {
-                res.push("run".to_string());
+                args.push("run".to_string());
                 if let Some(spec) = spec {
-                    spec.push_to(&mut res);
+                    spec.push_to(&mut args);
                 }
             }
         }
-        Ok(res)
+        Ok((args, extra_args))
     }
 
     pub(crate) fn for_file(
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index 084e17b04..6b9a11a87 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -55,6 +55,9 @@ pub struct ServerConfig {
 
     /// Cargo feature configurations.
     pub cargo_features: CargoFeatures,
+
+    /// Enabled if the vscode_lldb extension is available.
+    pub vscode_lldb: bool,
 }
 
 impl Default for ServerConfig {
@@ -76,6 +79,7 @@ impl Default for ServerConfig {
             additional_out_dirs: FxHashMap::default(),
             cargo_features: Default::default(),
             rustfmt_args: Vec::new(),
+            vscode_lldb: false,
         }
     }
 }
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 2b3b16d35..1fefc66aa 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -16,7 +16,10 @@ use std::{
 
 use crossbeam_channel::{select, unbounded, RecvError, Sender};
 use lsp_server::{Connection, ErrorCode, Message, Notification, Request, RequestId, Response};
-use lsp_types::{ClientCapabilities, NumberOrString};
+use lsp_types::{
+    ClientCapabilities, NumberOrString, WorkDoneProgress, WorkDoneProgressBegin,
+    WorkDoneProgressCreateParams, WorkDoneProgressEnd, WorkDoneProgressReport,
+};
 use ra_cargo_watch::{url_from_path_with_drive_lowercasing, CheckOptions, CheckTask};
 use ra_ide::{Canceled, FileId, InlayHintsOptions, LibraryData, SourceRootId};
 use ra_prof::profile;
@@ -189,6 +192,7 @@ pub fn main_loop(
                     all_targets: config.cargo_watch_all_targets,
                 },
                 rustfmt_args: config.rustfmt_args,
+                vscode_lldb: config.vscode_lldb,
             }
         };
 
@@ -329,6 +333,7 @@ struct LoopState {
     in_flight_libraries: usize,
     pending_libraries: Vec<(SourceRootId, Vec<(FileId, RelativePathBuf, Arc<String>)>)>,
     workspace_loaded: bool,
+    roots_scanned_progress: Option<usize>,
 }
 
 impl LoopState {
@@ -428,17 +433,15 @@ fn loop_turn(
         && loop_state.in_flight_libraries == 0
     {
         loop_state.workspace_loaded = true;
-        let n_packages: usize = world_state.workspaces.iter().map(|it| it.n_packages()).sum();
-        if world_state.feature_flags.get("notifications.workspace-loaded") {
-            let msg = format!("workspace loaded, {} rust packages", n_packages);
-            show_message(req::MessageType::Info, msg, &connection.sender);
-        }
         world_state.check_watcher.update();
         pool.execute({
             let subs = loop_state.subscriptions.subscriptions();
             let snap = world_state.snapshot();
             move || snap.analysis().prime_caches(subs).unwrap_or_else(|_: Canceled| ())
         });
+        send_startup_progress(&connection.sender, loop_state, world_state);
+    } else if !loop_state.workspace_loaded {
+        send_startup_progress(&connection.sender, loop_state, world_state);
     }
 
     if state_changed {
@@ -703,6 +706,65 @@ fn on_diagnostic_task(task: DiagnosticTask, msg_sender: &Sender<Message>, state:
     }
 }
 
+fn send_startup_progress(
+    sender: &Sender<Message>,
+    loop_state: &mut LoopState,
+    world_state: &WorldState,
+) {
+    if !world_state.feature_flags.get("notifications.workspace-loaded") {
+        return;
+    }
+
+    let total: usize = world_state.workspaces.iter().map(|it| it.n_packages()).sum();
+    let prev_progress = loop_state.roots_scanned_progress;
+    let progress = total - world_state.roots_to_scan;
+    loop_state.roots_scanned_progress = Some(progress);
+
+    match (prev_progress, loop_state.workspace_loaded) {
+        (None, false) => {
+            let work_done_progress_create = request_new::<req::WorkDoneProgressCreate>(
+                loop_state.next_request_id(),
+                WorkDoneProgressCreateParams {
+                    token: req::ProgressToken::String("rustAnalyzer/startup".into()),
+                },
+            );
+            sender.send(work_done_progress_create.into()).unwrap();
+            send_startup_progress_notif(
+                sender,
+                WorkDoneProgress::Begin(WorkDoneProgressBegin {
+                    title: "rust-analyzer".into(),
+                    cancellable: None,
+                    message: Some(format!("{}/{} packages", progress, total)),
+                    percentage: Some(100.0 * progress as f64 / total as f64),
+                }),
+            );
+        }
+        (Some(prev), false) if progress != prev => send_startup_progress_notif(
+            sender,
+            WorkDoneProgress::Report(WorkDoneProgressReport {
+                cancellable: None,
+                message: Some(format!("{}/{} packages", progress, total)),
+                percentage: Some(100.0 * progress as f64 / total as f64),
+            }),
+        ),
+        (_, true) => send_startup_progress_notif(
+            sender,
+            WorkDoneProgress::End(WorkDoneProgressEnd {
+                message: Some(format!("rust-analyzer loaded, {} packages", progress)),
+            }),
+        ),
+        _ => {}
+    }
+}
+
+fn send_startup_progress_notif(sender: &Sender<Message>, work_done_progress: WorkDoneProgress) {
+    let notif = notification_new::<req::Progress>(req::ProgressParams {
+        token: req::ProgressToken::String("rustAnalyzer/startup".into()),
+        value: req::ProgressParamsValue::WorkDone(work_done_progress),
+    });
+    sender.send(notif.into()).unwrap();
+}
+
 struct PoolDispatcher<'a> {
     req: Option<Request>,
     pool: &'a ThreadPool,
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index 6482f3b77..1cc2f6571 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -381,6 +381,7 @@ pub fn handle_runnables(
         label,
         bin: "cargo".to_string(),
         args: check_args,
+        extra_args: Vec::new(),
         env: FxHashMap::default(),
         cwd: workspace_root.map(|root| root.to_string_lossy().to_string()),
     });
@@ -794,18 +795,35 @@ pub fn handle_code_lens(
             RunnableKind::Bin => "Run",
         }
         .to_string();
-        let r = to_lsp_runnable(&world, file_id, runnable)?;
+        let mut r = to_lsp_runnable(&world, file_id, runnable)?;
         let lens = CodeLens {
             range: r.range,
             command: Some(Command {
                 title,
                 command: "rust-analyzer.runSingle".into(),
-                arguments: Some(vec![to_value(r).unwrap()]),
+                arguments: Some(vec![to_value(&r).unwrap()]),
             }),
             data: None,
         };
-
         lenses.push(lens);
+
+        if world.options.vscode_lldb {
+            if r.args[0] == "run" {
+                r.args[0] = "build".into();
+            } else {
+                r.args.push("--no-run".into());
+            }
+            let debug_lens = CodeLens {
+                range: r.range,
+                command: Some(Command {
+                    title: "Debug".into(),
+                    command: "rust-analyzer.debugSingle".into(),
+                    arguments: Some(vec![to_value(r).unwrap()]),
+                }),
+                data: None,
+            };
+            lenses.push(debug_lens);
+        }
     }
 
     // Handle impls
@@ -914,7 +932,10 @@ pub fn handle_document_highlight(
 
 pub fn handle_ssr(world: WorldSnapshot, params: req::SsrParams) -> Result<req::SourceChange> {
     let _p = profile("handle_ssr");
-    world.analysis().structural_search_replace(&params.arg)??.try_conv_with(&world)
+    world
+        .analysis()
+        .structural_search_replace(&params.query, params.parse_only)??
+        .try_conv_with(&world)
 }
 
 pub fn publish_diagnostics(world: &WorldSnapshot, file_id: FileId) -> Result<DiagnosticTask> {
@@ -952,7 +973,7 @@ fn to_lsp_runnable(
     runnable: Runnable,
 ) -> Result<req::Runnable> {
     let spec = CargoTargetSpec::for_file(world, file_id)?;
-    let args = CargoTargetSpec::runnable_args(spec, &runnable.kind)?;
+    let (args, extra_args) = CargoTargetSpec::runnable_args(spec, &runnable.kind)?;
     let line_index = world.analysis().file_line_index(file_id)?;
     let label = match &runnable.kind {
         RunnableKind::Test { test_id } => format!("test {}", test_id),
@@ -965,6 +986,7 @@ fn to_lsp_runnable(
         label,
         bin: "cargo".to_string(),
         args,
+        extra_args,
         env: {
             let mut m = FxHashMap::default();
             m.insert("RUST_BACKTRACE".to_string(), "short".to_string());
@@ -973,6 +995,7 @@ fn to_lsp_runnable(
         cwd: world.workspace_root_for(file_id).map(|root| root.to_string_lossy().to_string()),
     })
 }
+
 fn highlight(world: &WorldSnapshot, file_id: FileId) -> Result<Vec<Decoration>> {
     let line_index = world.analysis().file_line_index(file_id)?;
     let res = world
diff --git a/crates/rust-analyzer/src/req.rs b/crates/rust-analyzer/src/req.rs
index a3efe3b9f..9e27d3f1c 100644
--- a/crates/rust-analyzer/src/req.rs
+++ b/crates/rust-analyzer/src/req.rs
@@ -169,6 +169,7 @@ pub struct Runnable {
     pub label: String,
     pub bin: String,
     pub args: Vec<String>,
+    pub extra_args: Vec<String>,
     pub env: FxHashMap<String, String>,
     pub cwd: Option<String>,
 }
@@ -217,6 +218,8 @@ impl Request for Ssr {
 }
 
 #[derive(Debug, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct SsrParams {
-    pub arg: String,
+    pub query: String,
+    pub parse_only: bool,
 }
diff --git a/crates/rust-analyzer/src/world.rs b/crates/rust-analyzer/src/world.rs
index 058ce2af8..5743471bf 100644
--- a/crates/rust-analyzer/src/world.rs
+++ b/crates/rust-analyzer/src/world.rs
@@ -38,6 +38,7 @@ pub struct Options {
     pub inlay_hints: InlayHintsOptions,
     pub rustfmt_args: Vec<String>,
     pub cargo_watch: CheckOptions,
+    pub vscode_lldb: bool,
 }
 
 /// `WorldState` is the primary mutable state of the language server
diff --git a/crates/rust-analyzer/tests/heavy_tests/main.rs b/crates/rust-analyzer/tests/heavy_tests/main.rs
index 970185dec..145429571 100644
--- a/crates/rust-analyzer/tests/heavy_tests/main.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/main.rs
@@ -75,7 +75,8 @@ fn foo() {
         RunnablesParams { text_document: server.doc_id("lib.rs"), position: None },
         json!([
           {
-            "args": [ "test", "--", "foo", "--nocapture" ],
+            "args": [ "test" ],
+            "extraArgs": [ "foo", "--nocapture" ],
             "bin": "cargo",
             "env": { "RUST_BACKTRACE": "short" },
             "cwd": null,
@@ -90,6 +91,7 @@ fn foo() {
               "check",
               "--all"
             ],
+            "extraArgs": [],
             "bin": "cargo",
             "env": {},
             "cwd": null,
@@ -141,13 +143,11 @@ fn main() {}
 
     server.wait_until_workspace_is_loaded();
     server.request::<Runnables>(
-        RunnablesParams {
-            text_document: server.doc_id("foo/tests/spam.rs"),
-            position: None,
-        },
+        RunnablesParams { text_document: server.doc_id("foo/tests/spam.rs"), position: None },
         json!([
           {
-            "args": [ "test", "--package", "foo", "--test", "spam", "--", "test_eggs", "--exact", "--nocapture" ],
+            "args": [ "test", "--package", "foo", "--test", "spam" ],
+            "extraArgs": [ "test_eggs", "--exact", "--nocapture" ],
             "bin": "cargo",
             "env": { "RUST_BACKTRACE": "short" },
             "label": "test test_eggs",
@@ -165,6 +165,7 @@ fn main() {}
               "--test",
               "spam"
             ],
+            "extraArgs": [],
             "bin": "cargo",
             "env": {},
             "cwd": server.path().join("foo"),
@@ -180,7 +181,7 @@ fn main() {}
               }
             }
           }
-        ])
+        ]),
     );
 }
 
diff --git a/crates/rust-analyzer/tests/heavy_tests/support.rs b/crates/rust-analyzer/tests/heavy_tests/support.rs
index e28ae61fe..1d7062bdf 100644
--- a/crates/rust-analyzer/tests/heavy_tests/support.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/support.rs
@@ -12,13 +12,14 @@ use lsp_types::{
     notification::{DidOpenTextDocument, Exit},
     request::Shutdown,
     ClientCapabilities, DidOpenTextDocumentParams, GotoCapability, TextDocumentClientCapabilities,
-    TextDocumentIdentifier, TextDocumentItem, Url,
+    TextDocumentIdentifier, TextDocumentItem, Url, WorkDoneProgress,
 };
 use serde::Serialize;
 use serde_json::{to_string_pretty, Value};
 use tempfile::TempDir;
 use test_utils::{find_mismatch, parse_fixture};
 
+use req::{ProgressParams, ProgressParamsValue};
 use rust_analyzer::{main_loop, req, ServerConfig};
 
 pub struct Project<'a> {
@@ -201,10 +202,14 @@ impl Server {
     }
     pub fn wait_until_workspace_is_loaded(&self) {
         self.wait_for_message_cond(1, &|msg: &Message| match msg {
-            Message::Notification(n) if n.method == "window/showMessage" => {
-                let msg =
-                    n.clone().extract::<req::ShowMessageParams>("window/showMessage").unwrap();
-                msg.message.starts_with("workspace loaded")
+            Message::Notification(n) if n.method == "$/progress" => {
+                match n.clone().extract::<ProgressParams>("$/progress").unwrap() {
+                    ProgressParams {
+                        token: req::ProgressToken::String(ref token),
+                        value: ProgressParamsValue::WorkDone(WorkDoneProgress::End(_)),
+                    } if token == "rustAnalyzer/startup" => true,
+                    _ => false,
+                }
             }
             _ => false,
         })
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index a0d8f4d37..db03df1c4 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -397,6 +397,8 @@ pub fn skip_slow_tests() -> bool {
     should_skip
 }
 
+const REWRITE: bool = false;
+
 /// Asserts that `expected` and `actual` strings are equal. If they differ only
 /// in trailing or leading whitespace the test won't fail and
 /// the contents of `actual` will be written to the file located at `path`.
@@ -412,7 +414,6 @@ fn assert_equal_text(expected: &str, actual: &str, path: &Path) {
         fs::write(path, actual).unwrap();
         return;
     }
-    const REWRITE: bool = false;
     if REWRITE {
         println!("rewriting {}", pretty_path.display());
         fs::write(path, actual).unwrap();
diff --git a/docs/user/readme.adoc b/docs/user/readme.adoc
index 4e99dd0a6..2e6c6112f 100644
--- a/docs/user/readme.adoc
+++ b/docs/user/readme.adoc
@@ -65,6 +65,25 @@ Note that we only support the latest version of VS Code.
 
 The extension will be updated automatically as new versions become available. It will ask your permission to download the matching language server version binary if needed.
 
+===== Nightly
+
+We ship nightly releases for VS Code. To help us out with testing the newest code and follow the bleeding edge of our `master`, please use the following config:
+
+[source,json]
+----
+{ "rust-analyzer.updates.channel": "nightly" }
+----
+
+You will be prompted to install the `nightly` extension version. Just click `Download now` and from that moment you will get automatic updates each 24 hours.
+
+If you don't want to be asked for `Download now` every day when the new nightly version is released add the following to your `settings.json`:
+[source,json]
+----
+{ "rust-analyzer.updates.askBeforeDownload": false }
+----
+
+NOTE: Nightly extension should **only** be installed via the `Download now` action from VS Code.
+
 ==== Building From Source
 
 Alternatively, both the server and the plugin can be installed from source:
diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index b07964546..575dc7c4a 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -1,6 +1,6 @@
 {
     "name": "rust-analyzer",
-    "version": "0.2.20200211-dev",
+    "version": "0.2.20200309-nightly",
     "lockfileVersion": 1,
     "requires": true,
     "dependencies": {
diff --git a/editors/code/package.json b/editors/code/package.json
index 3aaae357a..faf10528d 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -6,7 +6,7 @@
     "private": true,
     "icon": "icon.png",
     "//": "The real version is in release.yaml, this one just needs to be bigger",
-    "version": "0.2.20200211-dev",
+    "version": "0.2.20200309-nightly",
     "publisher": "matklad",
     "repository": {
         "url": "https://github.com/rust-analyzer/rust-analyzer.git",
@@ -219,6 +219,19 @@
                         }
                     }
                 },
+                "rust-analyzer.updates.channel": {
+                    "type": "string",
+                    "enum": [
+                        "stable",
+                        "nightly"
+                    ],
+                    "default": "stable",
+                    "markdownEnumDescriptions": [
+                        "`\"stable\"` updates are shipped weekly, they don't contain cutting-edge features from VSCode proposed APIs but have less bugs in general",
+                        "`\"nightly\"` updates are shipped daily, they contain cutting-edge features and latest bug fixes. These releases help us get your feedback very quickly and speed up rust-analyzer development **drastically**"
+                    ],
+                    "markdownDescription": "Choose `\"nightly\"` updates to get the latest features and bug fixes every day. While `\"stable\"` releases occur weekly and don't contain cutting-edge features from VSCode proposed APIs"
+                },
                 "rust-analyzer.updates.askBeforeDownload": {
                     "type": "boolean",
                     "default": true,
@@ -235,7 +248,7 @@
                         "string"
                     ],
                     "default": null,
-                    "description": "Path to rust-analyzer executable (points to bundled binary by default)"
+                    "description": "Path to rust-analyzer executable (points to bundled binary by default). If this is set, then \"rust-analyzer.updates.channel\" setting is not used"
                 },
                 "rust-analyzer.excludeGlobs": {
                     "type": "array",
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index b2c830b30..d65454275 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -46,6 +46,7 @@ export async function createClient(config: Config, serverPath: string): Promise<
             withSysroot: config.withSysroot,
             cargoFeatures: config.cargoFeatures,
             rustfmtArgs: config.rustfmtArgs,
+            vscodeLldb: vscode.extensions.getExtension("vadimcn.vscode-lldb") != null,
         },
         traceOutputChannel,
         middleware: {
diff --git a/editors/code/src/commands/runnables.ts b/editors/code/src/commands/runnables.ts
index 06b513466..357155163 100644
--- a/editors/code/src/commands/runnables.ts
+++ b/editors/code/src/commands/runnables.ts
@@ -62,6 +62,26 @@ export function runSingle(ctx: Ctx): Cmd {
     };
 }
 
+export function debugSingle(ctx: Ctx): Cmd {
+    return async (config: ra.Runnable) => {
+        const editor = ctx.activeRustEditor;
+        if (!editor) return;
+
+        const debugConfig = {
+            type: "lldb",
+            request: "launch",
+            name: config.label,
+            cargo: {
+                args: config.args,
+            },
+            args: config.extraArgs,
+            cwd: config.cwd
+        };
+
+        return vscode.debug.startDebugging(undefined, debugConfig);
+    };
+}
+
 class RunnableQuickPick implements vscode.QuickPickItem {
     public label: string;
     public description?: string | undefined;
@@ -87,7 +107,7 @@ function createTask(spec: ra.Runnable): vscode.Task {
         type: 'cargo',
         label: spec.label,
         command: spec.bin,
-        args: spec.args,
+        args: spec.extraArgs ? [...spec.args, '--', ...spec.extraArgs] : spec.args,
         env: spec.env,
     };
 
diff --git a/editors/code/src/commands/server_version.ts b/editors/code/src/commands/server_version.ts
index 421301b42..c4d84b443 100644
--- a/editors/code/src/commands/server_version.ts
+++ b/editors/code/src/commands/server_version.ts
@@ -5,7 +5,7 @@ import { spawnSync } from 'child_process';
 
 export function serverVersion(ctx: Ctx): Cmd {
     return async () => {
-        const binaryPath = await ensureServerBinary(ctx.config.serverSource);
+        const binaryPath = await ensureServerBinary(ctx.config);
 
         if (binaryPath == null) {
             throw new Error(
@@ -18,4 +18,3 @@ export function serverVersion(ctx: Ctx): Cmd {
         vscode.window.showInformationMessage('rust-analyzer version : ' + version);
     };
 }
-
diff --git a/editors/code/src/commands/ssr.ts b/editors/code/src/commands/ssr.ts
index eee48c693..6fee051fd 100644
--- a/editors/code/src/commands/ssr.ts
+++ b/editors/code/src/commands/ssr.ts
@@ -10,20 +10,22 @@ export function ssr(ctx: Ctx): Cmd {
         if (!client) return;
 
         const options: vscode.InputBoxOptions = {
-            placeHolder: "foo($a:expr, $b:expr) ==>> bar($a, foo($b))",
-            prompt: "Enter request",
-            validateInput: (x: string) => {
-                if (x.includes('==>>')) {
-                    return null;
+            value: "() ==>> ()",
+            prompt: "EnteR request, for example 'Foo($a:expr) ==> Foo::new($a)' ",
+            validateInput: async (x: string) => {
+                try {
+                    await client.sendRequest(ra.ssr, { query: x, parseOnly: true });
+                } catch (e) {
+                    return e.toString();
                 }
-                return "Enter request: pattern ==>> template";
+                return null;
             }
         };
         const request = await vscode.window.showInputBox(options);
 
         if (!request) return;
 
-        const change = await client.sendRequest(ra.ssr, { arg: request });
+        const change = await client.sendRequest(ra.ssr, { query: request, parseOnly: false });
 
         await applySourceChange(ctx, change);
     };
diff --git a/editors/code/src/config.ts b/editors/code/src/config.ts
index 6db073bec..f63e1d20e 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -1,7 +1,7 @@
 import * as os from "os";
 import * as vscode from 'vscode';
 import { ArtifactSource } from "./installation/interfaces";
-import { log } from "./util";
+import { log, vscodeReloadWindow } from "./util";
 
 const RA_LSP_DEBUG = process.env.__RA_LSP_SERVER_DEBUG;
 
@@ -23,25 +23,40 @@ export interface CargoFeatures {
     allFeatures: boolean;
     features: string[];
 }
+
+export const enum UpdatesChannel {
+    Stable = "stable",
+    Nightly = "nightly"
+}
+
+export const NIGHTLY_TAG = "nightly";
 export class Config {
-    private static readonly rootSection = "rust-analyzer";
-    private static readonly requiresReloadOpts = [
+    readonly extensionId = "matklad.rust-analyzer";
+
+    private readonly rootSection = "rust-analyzer";
+    private readonly requiresReloadOpts = [
+        "serverPath",
         "cargoFeatures",
         "cargo-watch",
         "highlighting.semanticTokens",
         "inlayHints",
     ]
-        .map(opt => `${Config.rootSection}.${opt}`);
+        .map(opt => `${this.rootSection}.${opt}`);
 
-    private static readonly extensionVersion: string = (() => {
-        const packageJsonVersion = vscode
-            .extensions
-            .getExtension("matklad.rust-analyzer")!
-            .packageJSON
-            .version as string; // n.n.YYYYMMDD
+    readonly packageJsonVersion = vscode
+        .extensions
+        .getExtension(this.extensionId)!
+        .packageJSON
+        .version as string; // n.n.YYYYMMDD[-nightly]
+
+    /**
+     * Either `nightly` or `YYYY-MM-DD` (i.e. `stable` release)
+     */
+    readonly extensionReleaseTag: string = (() => {
+        if (this.packageJsonVersion.endsWith(NIGHTLY_TAG)) return NIGHTLY_TAG;
 
         const realVersionRegexp = /^\d+\.\d+\.(\d{4})(\d{2})(\d{2})/;
-        const [, yyyy, mm, dd] = packageJsonVersion.match(realVersionRegexp)!;
+        const [, yyyy, mm, dd] = this.packageJsonVersion.match(realVersionRegexp)!;
 
         return `${yyyy}-${mm}-${dd}`;
     })();
@@ -54,16 +69,19 @@ export class Config {
     }
 
     private refreshConfig() {
-        this.cfg = vscode.workspace.getConfiguration(Config.rootSection);
+        this.cfg = vscode.workspace.getConfiguration(this.rootSection);
         const enableLogging = this.cfg.get("trace.extension") as boolean;
         log.setEnabled(enableLogging);
-        log.debug("Using configuration:", this.cfg);
+        log.debug(
+            "Extension version:", this.packageJsonVersion,
+            "using configuration:", this.cfg
+        );
     }
 
     private async onConfigChange(event: vscode.ConfigurationChangeEvent) {
         this.refreshConfig();
 
-        const requiresReloadOpt = Config.requiresReloadOpts.find(
+        const requiresReloadOpt = this.requiresReloadOpts.find(
             opt => event.affectsConfiguration(opt)
         );
 
@@ -75,7 +93,7 @@ export class Config {
         );
 
         if (userResponse === "Reload now") {
-            vscode.commands.executeCommand("workbench.action.reloadWindow");
+            await vscodeReloadWindow();
         }
     }
 
@@ -121,8 +139,14 @@ export class Config {
         }
     }
 
+    get installedExtensionUpdateChannel(): UpdatesChannel {
+        return this.extensionReleaseTag === NIGHTLY_TAG
+            ? UpdatesChannel.Nightly
+            : UpdatesChannel.Stable;
+    }
+
     get serverSource(): null | ArtifactSource {
-        const serverPath = RA_LSP_DEBUG ?? this.cfg.get<null | string>("serverPath");
+        const serverPath = RA_LSP_DEBUG ?? this.serverPath;
 
         if (serverPath) {
             return {
@@ -135,13 +159,18 @@ export class Config {
 
         if (!prebuiltBinaryName) return null;
 
+        return this.createGithubReleaseSource(
+            prebuiltBinaryName,
+            this.extensionReleaseTag
+        );
+    }
+
+    private createGithubReleaseSource(file: string, tag: string): ArtifactSource.GithubRelease {
         return {
             type: ArtifactSource.Type.GithubRelease,
+            file,
+            tag,
             dir: this.ctx.globalStoragePath,
-            file: prebuiltBinaryName,
-            storage: this.ctx.globalState,
-            tag: Config.extensionVersion,
-            askBeforeDownload: this.cfg.get("updates.askBeforeDownload") as boolean,
             repo: {
                 name: "rust-analyzer",
                 owner: "rust-analyzer",
@@ -149,9 +178,23 @@ export class Config {
         };
     }
 
+    get nightlyVsixSource(): ArtifactSource.GithubRelease {
+        return this.createGithubReleaseSource("rust-analyzer.vsix", NIGHTLY_TAG);
+    }
+
+    readonly installedNightlyExtensionReleaseDate = new DateStorage(
+        "installed-nightly-extension-release-date",
+        this.ctx.globalState
+    );
+    readonly serverReleaseDate = new DateStorage("server-release-date", this.ctx.globalState);
+    readonly serverReleaseTag = new Storage<null | string>("server-release-tag", this.ctx.globalState, null);
+
     // We don't do runtime config validation here for simplicity. More on stackoverflow:
     // https://stackoverflow.com/questions/60135780/what-is-the-best-way-to-type-check-the-configuration-for-vscode-extension
 
+    private get serverPath() { return this.cfg.get("serverPath") as null | string; }
+    get updatesChannel() { return this.cfg.get("updates.channel") as UpdatesChannel; }
+    get askBeforeDownload() { return this.cfg.get("updates.askBeforeDownload") as boolean; }
     get highlightingSemanticTokens() { return this.cfg.get("highlighting.semanticTokens") as boolean; }
     get highlightingOn() { return this.cfg.get("highlightingOn") as boolean; }
     get rainbowHighlightingOn() { return this.cfg.get("rainbowHighlightingOn") as boolean; }
@@ -189,3 +232,37 @@ export class Config {
     // for internal use
     get withSysroot() { return this.cfg.get("withSysroot", true) as boolean; }
 }
+
+export class Storage<T> {
+    constructor(
+        private readonly key: string,
+        private readonly storage: vscode.Memento,
+        private readonly defaultVal: T
+    ) { }
+
+    get(): T {
+        const val = this.storage.get(this.key, this.defaultVal);
+        log.debug(this.key, "==", val);
+        return val;
+    }
+    async set(val: T) {
+        log.debug(this.key, "=", val);
+        await this.storage.update(this.key, val);
+    }
+}
+export class DateStorage {
+    inner: Storage<null | string>;
+
+    constructor(key: string, storage: vscode.Memento) {
+        this.inner = new Storage(key, storage, null);
+    }
+
+    get(): null | Date {
+        const dateStr = this.inner.get();
+        return dateStr ? new Date(dateStr) : null;
+    }
+
+    async set(date: null | Date) {
+        await this.inner.set(date ? date.toString() : null);
+    }
+}
diff --git a/editors/code/src/installation/download_artifact.ts b/editors/code/src/installation/download_artifact.ts
deleted file mode 100644
index 97e4d67c2..000000000
--- a/editors/code/src/installation/download_artifact.ts
+++ /dev/null
@@ -1,50 +0,0 @@
-import * as vscode from "vscode";
-import * as path from "path";
-import { promises as fs } from "fs";
-
-import { ArtifactReleaseInfo } from "./interfaces";
-import { downloadFile } from "./download_file";
-import { assert } from "../util";
-
-/**
- * Downloads artifact from given `downloadUrl`.
- * Creates `installationDir` if it is not yet created and put the artifact under
- * `artifactFileName`.
- * Displays info about the download progress in an info message printing the name
- * of the artifact as `displayName`.
- */
-export async function downloadArtifact(
-    { downloadUrl, releaseName }: ArtifactReleaseInfo,
-    artifactFileName: string,
-    installationDir: string,
-    displayName: string,
-) {
-    await fs.mkdir(installationDir).catch(err => assert(
-        err?.code === "EEXIST",
-        `Couldn't create directory "${installationDir}" to download ` +
-        `${artifactFileName} artifact: ${err?.message}`
-    ));
-
-    const installationPath = path.join(installationDir, artifactFileName);
-
-    await vscode.window.withProgress(
-        {
-            location: vscode.ProgressLocation.Notification,
-            cancellable: false, // FIXME: add support for canceling download?
-            title: `Downloading ${displayName} (${releaseName})`
-        },
-        async (progress, _cancellationToken) => {
-            let lastPrecentage = 0;
-            const filePermissions = 0o755; // (rwx, r_x, r_x)
-            await downloadFile(downloadUrl, installationPath, filePermissions, (readBytes, totalBytes) => {
-                const newPercentage = (readBytes / totalBytes) * 100;
-                progress.report({
-                    message: newPercentage.toFixed(0) + "%",
-                    increment: newPercentage - lastPrecentage
-                });
-
-                lastPrecentage = newPercentage;
-            });
-        }
-    );
-}
diff --git a/editors/code/src/installation/download_file.ts b/editors/code/src/installation/downloads.ts
index ee8949d61..7ce2e2960 100644
--- a/editors/code/src/installation/download_file.ts
+++ b/editors/code/src/installation/downloads.ts
@@ -1,8 +1,11 @@
 import fetch from "node-fetch";
+import * as vscode from "vscode";
+import * as path from "path";
 import * as fs from "fs";
 import * as stream from "stream";
 import * as util from "util";
 import { log, assert } from "../util";
+import { ArtifactReleaseInfo } from "./interfaces";
 
 const pipeline = util.promisify(stream.pipeline);
 
@@ -49,3 +52,46 @@ export async function downloadFile(
         // Issue at nodejs repo: https://github.com/nodejs/node/issues/31776
     });
 }
+
+/**
+ * Downloads artifact from given `downloadUrl`.
+ * Creates `installationDir` if it is not yet created and puts the artifact under
+ * `artifactFileName`.
+ * Displays info about the download progress in an info message printing the name
+ * of the artifact as `displayName`.
+ */
+export async function downloadArtifactWithProgressUi(
+    { downloadUrl, releaseName }: ArtifactReleaseInfo,
+    artifactFileName: string,
+    installationDir: string,
+    displayName: string,
+) {
+    await fs.promises.mkdir(installationDir).catch(err => assert(
+        err?.code === "EEXIST",
+        `Couldn't create directory "${installationDir}" to download ` +
+        `${artifactFileName} artifact: ${err?.message}`
+    ));
+
+    const installationPath = path.join(installationDir, artifactFileName);
+
+    await vscode.window.withProgress(
+        {
+            location: vscode.ProgressLocation.Notification,
+            cancellable: false, // FIXME: add support for canceling download?
+            title: `Downloading rust-analyzer ${displayName} (${releaseName})`
+        },
+        async (progress, _cancellationToken) => {
+            let lastPrecentage = 0;
+            const filePermissions = 0o755; // (rwx, r_x, r_x)
+            await downloadFile(downloadUrl, installationPath, filePermissions, (readBytes, totalBytes) => {
+                const newPercentage = (readBytes / totalBytes) * 100;
+                progress.report({
+                    message: newPercentage.toFixed(0) + "%",
+                    increment: newPercentage - lastPrecentage
+                });
+
+                lastPrecentage = newPercentage;
+            });
+        }
+    );
+}
diff --git a/editors/code/src/installation/extension.ts b/editors/code/src/installation/extension.ts
new file mode 100644
index 000000000..eea6fded2
--- /dev/null
+++ b/editors/code/src/installation/extension.ts
@@ -0,0 +1,144 @@
+import * as vscode from "vscode";
+import * as path from "path";
+import { promises as fs } from 'fs';
+
+import { vscodeReinstallExtension, vscodeReloadWindow, log, vscodeInstallExtensionFromVsix, assert, notReentrant } from "../util";
+import { Config, UpdatesChannel } from "../config";
+import { ArtifactReleaseInfo, ArtifactSource } from "./interfaces";
+import { downloadArtifactWithProgressUi } from "./downloads";
+import { fetchArtifactReleaseInfo } from "./fetch_artifact_release_info";
+
+const HEURISTIC_NIGHTLY_RELEASE_PERIOD_IN_HOURS = 25;
+
+/**
+ * Installs `stable` or latest `nightly` version or does nothing if the current
+ * extension version is what's needed according to `desiredUpdateChannel`.
+ */
+export async function ensureProperExtensionVersion(config: Config): Promise<never | void> {
+    // User has built lsp server from sources, she should manage updates manually
+    if (config.serverSource?.type === ArtifactSource.Type.ExplicitPath) return;
+
+    const currentUpdChannel = config.installedExtensionUpdateChannel;
+    const desiredUpdChannel = config.updatesChannel;
+
+    if (currentUpdChannel === UpdatesChannel.Stable) {
+        // Release date is present only when we are on nightly
+        await config.installedNightlyExtensionReleaseDate.set(null);
+    }
+
+    if (desiredUpdChannel === UpdatesChannel.Stable) {
+        // VSCode should handle updates for stable channel
+        if (currentUpdChannel === UpdatesChannel.Stable) return;
+
+        if (!await askToDownloadProperExtensionVersion(config)) return;
+
+        await vscodeReinstallExtension(config.extensionId);
+        await vscodeReloadWindow(); // never returns
+    }
+
+    if (currentUpdChannel === UpdatesChannel.Stable) {
+        if (!await askToDownloadProperExtensionVersion(config)) return;
+
+        return await tryDownloadNightlyExtension(config);
+    }
+
+    const currentExtReleaseDate = config.installedNightlyExtensionReleaseDate.get();
+
+    if (currentExtReleaseDate === null) {
+        void vscode.window.showErrorMessage(
+            "Nightly release date must've been set during the installation. " +
+            "Did you download and install the nightly .vsix package manually?"
+        );
+        throw new Error("Nightly release date was not set in globalStorage");
+    }
+
+    const dateNow = new Date;
+    const hoursSinceLastUpdate = diffInHours(currentExtReleaseDate, dateNow);
+    log.debug(
+        "Current rust-analyzer nightly was downloaded", hoursSinceLastUpdate,
+        "hours ago, namely:", currentExtReleaseDate, "and now is", dateNow
+    );
+
+    if (hoursSinceLastUpdate < HEURISTIC_NIGHTLY_RELEASE_PERIOD_IN_HOURS) {
+        return;
+    }
+    if (!await askToDownloadProperExtensionVersion(config, "The installed nightly version is most likely outdated. ")) {
+        return;
+    }
+
+    await tryDownloadNightlyExtension(config, releaseInfo => {
+        assert(
+            currentExtReleaseDate.getTime() === config.installedNightlyExtensionReleaseDate.get()?.getTime(),
+            "Other active VSCode instance has reinstalled the extension"
+        );
+
+        if (releaseInfo.releaseDate.getTime() === currentExtReleaseDate.getTime()) {
+            vscode.window.showInformationMessage(
+                "Whoops, it appears that your nightly version is up-to-date. " +
+                "There might be some problems with the upcomming nightly release " +
+                "or you traveled too far into the future. Sorry for that 😅! "
+            );
+            return false;
+        }
+        return true;
+    });
+}
+
+async function askToDownloadProperExtensionVersion(config: Config, reason = "") {
+    if (!config.askBeforeDownload) return true;
+
+    const stableOrNightly = config.updatesChannel === UpdatesChannel.Stable ? "stable" : "latest nightly";
+
+    // In case of reentering this function and showing the same info message
+    // (e.g. after we had shown this message, the user changed the config)
+    // vscode will dismiss the already shown one (i.e. return undefined).
+    // This behaviour is what we want, but likely it is not documented
+
+    const userResponse = await vscode.window.showInformationMessage(
+        reason + `Do you want to download the ${stableOrNightly} rust-analyzer extension ` +
+        `version and reload the window now?`,
+        "Download now", "Cancel"
+    );
+    return userResponse === "Download now";
+}
+
+/**
+ * Shutdowns the process in case of success (i.e. reloads the window) or throws an error.
+ *
+ * ACHTUNG!: this function has a crazy amount of state transitions, handling errors during
+ * each of them would result in a ton of code (especially accounting for cross-process
+ * shared mutable `globalState` access). Enforcing no reentrancy for this is best-effort.
+ */
+const tryDownloadNightlyExtension = notReentrant(async (
+    config: Config,
+    shouldDownload: (releaseInfo: ArtifactReleaseInfo) => boolean = () => true
+): Promise<never | void> => {
+    const vsixSource = config.nightlyVsixSource;
+    try {
+        const releaseInfo = await fetchArtifactReleaseInfo(vsixSource.repo, vsixSource.file, vsixSource.tag);
+
+        if (!shouldDownload(releaseInfo)) return;
+
+        await downloadArtifactWithProgressUi(releaseInfo, vsixSource.file, vsixSource.dir, "nightly extension");
+
+        const vsixPath = path.join(vsixSource.dir, vsixSource.file);
+
+        await vscodeInstallExtensionFromVsix(vsixPath);
+        await config.installedNightlyExtensionReleaseDate.set(releaseInfo.releaseDate);
+        await fs.unlink(vsixPath);
+
+        await vscodeReloadWindow(); // never returns
+    } catch (err) {
+        log.downloadError(err, "nightly extension", vsixSource.repo.name);
+    }
+});
+
+function diffInHours(a: Date, b: Date): number {
+    // Discard the time and time-zone information (to abstract from daylight saving time bugs)
+    // https://stackoverflow.com/a/15289883/9259330
+
+    const utcA = Date.UTC(a.getFullYear(), a.getMonth(), a.getDate());
+    const utcB = Date.UTC(b.getFullYear(), b.getMonth(), b.getDate());
+
+    return (utcA - utcB) / (1000 * 60 * 60);
+}
diff --git a/editors/code/src/installation/fetch_artifact_release_info.ts b/editors/code/src/installation/fetch_artifact_release_info.ts
index b1b5a3485..1ad3b8338 100644
--- a/editors/code/src/installation/fetch_artifact_release_info.ts
+++ b/editors/code/src/installation/fetch_artifact_release_info.ts
@@ -59,12 +59,15 @@ export async function fetchArtifactReleaseInfo(
 
     return {
         releaseName: release.name,
+        releaseDate: new Date(release.published_at),
         downloadUrl: artifact.browser_download_url
     };
 
     // We omit declaration of tremendous amount of fields that we are not using here
     interface GithubRelease {
         name: string;
+        // eslint-disable-next-line camelcase
+        published_at: string;
         assets: Array<{
             name: string;
             // eslint-disable-next-line camelcase
diff --git a/editors/code/src/installation/interfaces.ts b/editors/code/src/installation/interfaces.ts
index 50b635921..1a8ea0884 100644
--- a/editors/code/src/installation/interfaces.ts
+++ b/editors/code/src/installation/interfaces.ts
@@ -1,5 +1,3 @@
-import * as vscode from "vscode";
-
 export interface GithubRepo {
     name: string;
     owner: string;
@@ -9,6 +7,7 @@ export interface GithubRepo {
  * Metadata about particular artifact retrieved from GitHub releases.
  */
 export interface ArtifactReleaseInfo {
+    releaseDate: Date;
     releaseName: string;
     downloadUrl: string;
 }
@@ -42,6 +41,9 @@ export namespace ArtifactSource {
          */
         repo: GithubRepo;
 
+
+        // FIXME: add installationPath: string;
+
         /**
          * Directory on the filesystem where the bundled binary is stored.
          */
@@ -57,17 +59,5 @@ export namespace ArtifactSource {
          * Tag of github release that denotes a version required by this extension.
          */
         tag: string;
-
-        /**
-         * Object that provides `get()/update()` operations to store metadata
-         * about the actual binary, e.g. its actual version.
-         */
-        storage: vscode.Memento;
-
-        /**
-         * Ask for the user permission before downloading the artifact.
-         */
-        askBeforeDownload: boolean;
     }
-
 }
diff --git a/editors/code/src/installation/server.ts b/editors/code/src/installation/server.ts
index ef1c45ff6..05730a778 100644
--- a/editors/code/src/installation/server.ts
+++ b/editors/code/src/installation/server.ts
@@ -1,14 +1,16 @@
 import * as vscode from "vscode";
 import * as path from "path";
-import { promises as dns } from "dns";
 import { spawnSync } from "child_process";
 
 import { ArtifactSource } from "./interfaces";
 import { fetchArtifactReleaseInfo } from "./fetch_artifact_release_info";
-import { downloadArtifact } from "./download_artifact";
-import { log, assert } from "../util";
+import { downloadArtifactWithProgressUi } from "./downloads";
+import { log, assert, notReentrant } from "../util";
+import { Config, NIGHTLY_TAG } from "../config";
+
+export async function ensureServerBinary(config: Config): Promise<null | string> {
+    const source = config.serverSource;
 
-export async function ensureServerBinary(source: null | ArtifactSource): Promise<null | string> {
     if (!source) {
         vscode.window.showErrorMessage(
             "Unfortunately we don't ship binaries for your platform yet. " +
@@ -35,18 +37,11 @@ export async function ensureServerBinary(source: null | ArtifactSource): Promise
             return null;
         }
         case ArtifactSource.Type.GithubRelease: {
-            const prebuiltBinaryPath = path.join(source.dir, source.file);
-
-            const installedVersion: null | string = getServerVersion(source.storage);
-            const requiredVersion: string = source.tag;
-
-            log.debug("Installed version:", installedVersion, "required:", requiredVersion);
-
-            if (isBinaryAvailable(prebuiltBinaryPath) && installedVersion === requiredVersion) {
-                return prebuiltBinaryPath;
+            if (!shouldDownloadServer(source, config)) {
+                return path.join(source.dir, source.file);
             }
 
-            if (source.askBeforeDownload) {
+            if (config.askBeforeDownload) {
                 const userResponse = await vscode.window.showInformationMessage(
                     `Language server version ${source.tag} for rust-analyzer is not installed. ` +
                     "Do you want to download it now?",
@@ -55,38 +50,56 @@ export async function ensureServerBinary(source: null | ArtifactSource): Promise
                 if (userResponse !== "Download now") return null;
             }
 
-            if (!await downloadServer(source)) return null;
-
-            return prebuiltBinaryPath;
+            return await downloadServer(source, config);
         }
     }
 }
 
-async function downloadServer(source: ArtifactSource.GithubRelease): Promise<boolean> {
+function shouldDownloadServer(
+    source: ArtifactSource.GithubRelease,
+    config: Config
+): boolean {
+    if (!isBinaryAvailable(path.join(source.dir, source.file))) return true;
+
+    const installed = {
+        tag: config.serverReleaseTag.get(),
+        date: config.serverReleaseDate.get()
+    };
+    const required = {
+        tag: source.tag,
+        date: config.installedNightlyExtensionReleaseDate.get()
+    };
+
+    log.debug("Installed server:", installed, "required:", required);
+
+    if (required.tag !== NIGHTLY_TAG || installed.tag !== NIGHTLY_TAG) {
+        return required.tag !== installed.tag;
+    }
+
+    assert(required.date !== null, "Extension release date should have been saved during its installation");
+    assert(installed.date !== null, "Server release date should have been saved during its installation");
+
+    return installed.date.getTime() !== required.date.getTime();
+}
+
+/**
+ * Enforcing no reentrancy for this is best-effort.
+ */
+const downloadServer = notReentrant(async (
+    source: ArtifactSource.GithubRelease,
+    config: Config,
+): Promise<null | string> => {
     try {
         const releaseInfo = await fetchArtifactReleaseInfo(source.repo, source.file, source.tag);
 
-        await downloadArtifact(releaseInfo, source.file, source.dir, "language server");
-        await setServerVersion(source.storage, releaseInfo.releaseName);
+        await downloadArtifactWithProgressUi(releaseInfo, source.file, source.dir, "language server");
+        await Promise.all([
+            config.serverReleaseTag.set(releaseInfo.releaseName),
+            config.serverReleaseDate.set(releaseInfo.releaseDate)
+        ]);
     } catch (err) {
-        vscode.window.showErrorMessage(
-            `Failed to download language server from ${source.repo.name} ` +
-            `GitHub repository: ${err.message}`
-        );
-
-        log.error(err);
-
-        dns.resolve('example.com').then(
-            addrs => log.debug("DNS resolution for example.com was successful", addrs),
-            err => {
-                log.error(
-                    "DNS resolution for example.com failed, " +
-                    "there might be an issue with Internet availability"
-                );
-                log.error(err);
-            }
-        );
-        return false;
+        log.downloadError(err, "language server", source.repo.name);
+        return null;
     }
 
     const binaryPath = path.join(source.dir, source.file);
@@ -101,8 +114,8 @@ async function downloadServer(source: ArtifactSource.GithubRelease): Promise<boo
         "Rust analyzer language server was successfully installed 🦀"
     );
 
-    return true;
-}
+    return binaryPath;
+});
 
 function isBinaryAvailable(binaryPath: string): boolean {
     const res = spawnSync(binaryPath, ["--version"]);
@@ -115,14 +128,3 @@ function isBinaryAvailable(binaryPath: string): boolean {
 
     return res.status === 0;
 }
-
-function getServerVersion(storage: vscode.Memento): null | string {
-    const version = storage.get<null | string>("server-version", null);
-    log.debug("Get server-version:", version);
-    return version;
-}
-
-async function setServerVersion(storage: vscode.Memento, version: string): Promise<void> {
-    log.debug("Set server-version:", version);
-    await storage.update("server-version", version.toString());
-}
diff --git a/editors/code/src/main.ts b/editors/code/src/main.ts
index ecf53cf77..bd4661a36 100644
--- a/editors/code/src/main.ts
+++ b/editors/code/src/main.ts
@@ -8,6 +8,7 @@ import { activateHighlighting } from './highlighting';
 import { ensureServerBinary } from './installation/server';
 import { Config } from './config';
 import { log } from './util';
+import { ensureProperExtensionVersion } from './installation/extension';
 
 let ctx: Ctx | undefined;
 
@@ -34,7 +35,13 @@ export async function activate(context: vscode.ExtensionContext) {
 
     const config = new Config(context);
 
-    const serverPath = await ensureServerBinary(config.serverSource);
+    vscode.workspace.onDidChangeConfiguration(() => ensureProperExtensionVersion(config).catch(log.error));
+
+    // Don't await the user response here, otherwise we will block the lsp server bootstrap
+    void ensureProperExtensionVersion(config).catch(log.error);
+
+    const serverPath = await ensureServerBinary(config);
+
     if (serverPath == null) {
         throw new Error(
             "Rust Analyzer Language Server is not available. " +
@@ -83,6 +90,7 @@ export async function activate(context: vscode.ExtensionContext) {
 
     // Internal commands which are invoked by the server.
     ctx.registerCommand('runSingle', commands.runSingle);
+    ctx.registerCommand('debugSingle', commands.debugSingle);
     ctx.registerCommand('showReferences', commands.showReferences);
     ctx.registerCommand('applySourceChange', commands.applySourceChange);
     ctx.registerCommand('selectAndApplySourceChange', commands.selectAndApplySourceChange);
diff --git a/editors/code/src/rust-analyzer-api.ts b/editors/code/src/rust-analyzer-api.ts
index bd6e3ada0..9846f7343 100644
--- a/editors/code/src/rust-analyzer-api.ts
+++ b/editors/code/src/rust-analyzer-api.ts
@@ -80,13 +80,12 @@ export interface Runnable {
     label: string;
     bin: string;
     args: Vec<string>;
+    extraArgs: Vec<string>;
     env: FxHashMap<string, string>;
     cwd: Option<string>;
 }
 export const runnables = request<RunnablesParams, Vec<Runnable>>("runnables");
 
-
-
 export type InlayHint = InlayHint.TypeHint | InlayHint.ParamHint;
 
 export namespace InlayHint {
@@ -108,7 +107,8 @@ export const inlayHints = request<InlayHintsParams, Vec<InlayHint>>("inlayHints"
 
 
 export interface SsrParams {
-    arg: string;
+    query: string;
+    parseOnly: boolean;
 }
 export const ssr = request<SsrParams, SourceChange>("ssr");
 
diff --git a/editors/code/src/util.ts b/editors/code/src/util.ts
index 95a5f1227..2bfc145e6 100644
--- a/editors/code/src/util.ts
+++ b/editors/code/src/util.ts
@@ -1,5 +1,6 @@
 import * as lc from "vscode-languageclient";
 import * as vscode from "vscode";
+import { promises as dns } from "dns";
 import { strict as nativeAssert } from "assert";
 
 export function assert(condition: boolean, explanation: string): asserts condition {
@@ -11,21 +12,40 @@ export function assert(condition: boolean, explanation: string): asserts conditi
     }
 }
 
-export const log = {
-    enabled: true,
+export const log = new class {
+    private enabled = true;
+
+    setEnabled(yes: boolean): void {
+        log.enabled = yes;
+    }
+
     debug(message?: any, ...optionalParams: any[]): void {
         if (!log.enabled) return;
         // eslint-disable-next-line no-console
         console.log(message, ...optionalParams);
-    },
+    }
+
     error(message?: any, ...optionalParams: any[]): void {
         if (!log.enabled) return;
         debugger;
         // eslint-disable-next-line no-console
         console.error(message, ...optionalParams);
-    },
-    setEnabled(yes: boolean): void {
-        log.enabled = yes;
+    }
+
+    downloadError(err: Error, artifactName: string, repoName: string) {
+        vscode.window.showErrorMessage(
+            `Failed to download the rust-analyzer ${artifactName} from ${repoName} ` +
+            `GitHub repository: ${err.message}`
+        );
+        log.error(err);
+        dns.resolve('example.com').then(
+            addrs => log.debug("DNS resolution for example.com was successful", addrs),
+            err => log.error(
+                "DNS resolution for example.com failed, " +
+                "there might be an issue with Internet availability",
+                err
+            )
+        );
     }
 };
 
@@ -66,6 +86,17 @@ function sleep(ms: number) {
     return new Promise(resolve => setTimeout(resolve, ms));
 }
 
+export function notReentrant<TThis, TParams extends any[], TRet>(
+    fn: (this: TThis, ...params: TParams) => Promise<TRet>
+): typeof fn {
+    let entered = false;
+    return function(...params) {
+        assert(!entered, `Reentrancy invariant for ${fn.name} is violated`);
+        entered = true;
+        return fn.apply(this, params).finally(() => entered = false);
+    };
+}
+
 export type RustDocument = vscode.TextDocument & { languageId: "rust" };
 export type RustEditor = vscode.TextEditor & { document: RustDocument; id: string };
 
@@ -79,3 +110,29 @@ export function isRustDocument(document: vscode.TextDocument): document is RustD
 export function isRustEditor(editor: vscode.TextEditor): editor is RustEditor {
     return isRustDocument(editor.document);
 }
+
+/**
+ * @param extensionId The canonical extension identifier in the form of: `publisher.name`
+ */
+export async function vscodeReinstallExtension(extensionId: string) {
+    // Unfortunately there is no straightforward way as of now, these commands
+    // were found in vscode source code.
+
+    log.debug("Uninstalling extension", extensionId);
+    await vscode.commands.executeCommand("workbench.extensions.uninstallExtension", extensionId);
+    log.debug("Installing extension", extensionId);
+    await vscode.commands.executeCommand("workbench.extensions.installExtension", extensionId);
+}
+
+export async function vscodeReloadWindow(): Promise<never> {
+    await vscode.commands.executeCommand("workbench.action.reloadWindow");
+
+    assert(false, "unreachable");
+}
+
+export async function vscodeInstallExtensionFromVsix(vsixPath: string) {
+    await vscode.commands.executeCommand(
+        "workbench.extensions.installExtension",
+        vscode.Uri.file(vsixPath)
+    );
+}
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index 014b61b37..e1472e85d 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -38,13 +38,11 @@ pub fn project_root() -> PathBuf {
 }
 
 pub fn run_rustfmt(mode: Mode) -> Result<()> {
+    let _dir = pushd(project_root());
     ensure_rustfmt()?;
 
-    if mode == Mode::Verify {
-        run!("rustup run {} -- cargo fmt -- --check", TOOLCHAIN)?;
-    } else {
-        run!("rustup run {} -- cargo fmt", TOOLCHAIN)?;
-    }
+    let check = if mode == Mode::Verify { "--check" } else { "" };
+    run!("rustup run {} -- cargo fmt -- {}", TOOLCHAIN, check)?;
     Ok(())
 }