33 files changed, 1595 insertions, 940 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 45804c087..f1651edaa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1247,6 +1247,7 @@ dependencies = [
 name = "ra_project_model"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "cargo_metadata",
  "log",
  "ra_arena",
diff --git a/crates/ra_assists/src/handlers/auto_import.rs b/crates/ra_assists/src/handlers/auto_import.rs
index 1fb701da5..c4aea2a06 100644
--- a/crates/ra_assists/src/handlers/auto_import.rs
+++ b/crates/ra_assists/src/handlers/auto_import.rs
@@ -1,10 +1,18 @@
-use ra_ide_db::imports_locator::ImportsLocator;
-use ra_syntax::ast::{self, AstNode};
-
 use crate::{
     assist_ctx::{Assist, AssistCtx},
     insert_use_statement, AssistId,
 };
+use hir::{
+    db::HirDatabase, AsAssocItem, AssocItemContainer, ModPath, Module, ModuleDef, PathResolution,
+    SourceAnalyzer, Trait, Type,
+};
+use ra_ide_db::{imports_locator::ImportsLocator, RootDatabase};
+use ra_prof::profile;
+use ra_syntax::{
+    ast::{self, AstNode},
+    SyntaxNode,
+};
+use rustc_hash::FxHashSet;
 use std::collections::BTreeSet;
 
 // Assist: auto_import
@@ -27,52 +35,24 @@ use std::collections::BTreeSet;
 // # pub mod std { pub mod collections { pub struct HashMap { } } }
 // ```
 pub(crate) fn auto_import(ctx: AssistCtx) -> Option<Assist> {
-    let path_under_caret: ast::Path = ctx.find_node_at_offset()?;
-    if path_under_caret.syntax().ancestors().find_map(ast::UseItem::cast).is_some() {
-        return None;
-    }
-
-    let module = path_under_caret.syntax().ancestors().find_map(ast::Module::cast);
-    let position = match module.and_then(|it| it.item_list()) {
-        Some(item_list) => item_list.syntax().clone(),
-        None => {
-            let current_file =
-                path_under_caret.syntax().ancestors().find_map(ast::SourceFile::cast)?;
-            current_file.syntax().clone()
-        }
-    };
-    let source_analyzer = ctx.source_analyzer(&position, None);
-    let module_with_name_to_import = source_analyzer.module()?;
-
-    let name_ref_to_import =
-        path_under_caret.syntax().descendants().find_map(ast::NameRef::cast)?;
-    if source_analyzer
-        .resolve_path(ctx.db, &name_ref_to_import.syntax().ancestors().find_map(ast::Path::cast)?)
-        .is_some()
-    {
-        return None;
-    }
-
-    let name_to_import = name_ref_to_import.syntax().to_string();
-    let proposed_imports = ImportsLocator::new(ctx.db)
-        .find_imports(&name_to_import)
-        .into_iter()
-        .filter_map(|module_def| module_with_name_to_import.find_use_path(ctx.db, module_def))
-        .filter(|use_path| !use_path.segments.is_empty())
-        .take(20)
-        .collect::<BTreeSet<_>>();
-
+    let auto_import_assets = AutoImportAssets::new(&ctx)?;
+    let proposed_imports = auto_import_assets.search_for_imports(ctx.db);
     if proposed_imports.is_empty() {
         return None;
     }
 
-    let mut group = ctx.add_assist_group(format!("Import {}", name_to_import));
+    let assist_group_name = if proposed_imports.len() == 1 {
+        format!("Import `{}`", proposed_imports.iter().next().unwrap())
+    } else {
+        auto_import_assets.get_import_group_message()
+    };
+    let mut group = ctx.add_assist_group(assist_group_name);
     for import in proposed_imports {
         group.add_assist(AssistId("auto_import"), format!("Import `{}`", &import), |edit| {
-            edit.target(path_under_caret.syntax().text_range());
+            edit.target(auto_import_assets.syntax_under_caret.text_range());
             insert_use_statement(
-                &position,
-                path_under_caret.syntax(),
+                &auto_import_assets.syntax_under_caret,
+                &auto_import_assets.syntax_under_caret,
                 &import,
                 edit.text_edit_builder(),
             );
@@ -81,11 +61,232 @@ pub(crate) fn auto_import(ctx: AssistCtx) -> Option<Assist> {
     group.finish()
 }
 
+struct AutoImportAssets {
+    import_candidate: ImportCandidate,
+    module_with_name_to_import: Module,
+    syntax_under_caret: SyntaxNode,
+}
+
+impl AutoImportAssets {
+    fn new(ctx: &AssistCtx) -> Option<Self> {
+        if let Some(path_under_caret) = ctx.find_node_at_offset::<ast::Path>() {
+            Self::for_regular_path(path_under_caret, &ctx)
+        } else {
+            Self::for_method_call(ctx.find_node_at_offset()?, &ctx)
+        }
+    }
+
+    fn for_method_call(method_call: ast::MethodCallExpr, ctx: &AssistCtx) -> Option<Self> {
+        let syntax_under_caret = method_call.syntax().to_owned();
+        let source_analyzer = ctx.source_analyzer(&syntax_under_caret, None);
+        let module_with_name_to_import = source_analyzer.module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_method_call(
+                &method_call,
+                &source_analyzer,
+                ctx.db,
+            )?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
+    }
+
+    fn for_regular_path(path_under_caret: ast::Path, ctx: &AssistCtx) -> Option<Self> {
+        let syntax_under_caret = path_under_caret.syntax().to_owned();
+        if syntax_under_caret.ancestors().find_map(ast::UseItem::cast).is_some() {
+            return None;
+        }
+
+        let source_analyzer = ctx.source_analyzer(&syntax_under_caret, None);
+        let module_with_name_to_import = source_analyzer.module()?;
+        Some(Self {
+            import_candidate: ImportCandidate::for_regular_path(
+                &path_under_caret,
+                &source_analyzer,
+                ctx.db,
+            )?,
+            module_with_name_to_import,
+            syntax_under_caret,
+        })
+    }
+
+    fn get_search_query(&self) -> &str {
+        match &self.import_candidate {
+            ImportCandidate::UnqualifiedName(name) => name,
+            ImportCandidate::QualifierStart(qualifier_start) => qualifier_start,
+            ImportCandidate::TraitAssocItem(_, trait_assoc_item_name) => trait_assoc_item_name,
+            ImportCandidate::TraitMethod(_, trait_method_name) => trait_method_name,
+        }
+    }
+
+    fn get_import_group_message(&self) -> String {
+        match &self.import_candidate {
+            ImportCandidate::UnqualifiedName(name) => format!("Import {}", name),
+            ImportCandidate::QualifierStart(qualifier_start) => {
+                format!("Import {}", qualifier_start)
+            }
+            ImportCandidate::TraitAssocItem(_, trait_assoc_item_name) => {
+                format!("Import a trait for item {}", trait_assoc_item_name)
+            }
+            ImportCandidate::TraitMethod(_, trait_method_name) => {
+                format!("Import a trait for method {}", trait_method_name)
+            }
+        }
+    }
+
+    fn search_for_imports(&self, db: &RootDatabase) -> BTreeSet<ModPath> {
+        let _p = profile("auto_import::search_for_imports");
+        let current_crate = self.module_with_name_to_import.krate();
+        ImportsLocator::new(db)
+            .find_imports(&self.get_search_query())
+            .into_iter()
+            .filter_map(|module_def| match &self.import_candidate {
+                ImportCandidate::TraitAssocItem(assoc_item_type, _) => {
+                    let located_assoc_item = match module_def {
+                        ModuleDef::Function(located_function) => located_function
+                            .as_assoc_item(db)
+                            .map(|assoc| assoc.container(db))
+                            .and_then(Self::assoc_to_trait),
+                        ModuleDef::Const(located_const) => located_const
+                            .as_assoc_item(db)
+                            .map(|assoc| assoc.container(db))
+                            .and_then(Self::assoc_to_trait),
+                        _ => None,
+                    }?;
+
+                    let mut trait_candidates = FxHashSet::default();
+                    trait_candidates.insert(located_assoc_item.into());
+
+                    assoc_item_type
+                        .iterate_path_candidates(
+                            db,
+                            current_crate,
+                            &trait_candidates,
+                            None,
+                            |_, assoc| Self::assoc_to_trait(assoc.container(db)),
+                        )
+                        .map(ModuleDef::from)
+                }
+                ImportCandidate::TraitMethod(function_callee, _) => {
+                    let located_assoc_item =
+                        if let ModuleDef::Function(located_function) = module_def {
+                            located_function
+                                .as_assoc_item(db)
+                                .map(|assoc| assoc.container(db))
+                                .and_then(Self::assoc_to_trait)
+                        } else {
+                            None
+                        }?;
+
+                    let mut trait_candidates = FxHashSet::default();
+                    trait_candidates.insert(located_assoc_item.into());
+
+                    function_callee
+                        .iterate_method_candidates(
+                            db,
+                            current_crate,
+                            &trait_candidates,
+                            None,
+                            |_, function| {
+                                Self::assoc_to_trait(function.as_assoc_item(db)?.container(db))
+                            },
+                        )
+                        .map(ModuleDef::from)
+                }
+                _ => Some(module_def),
+            })
+            .filter_map(|module_def| self.module_with_name_to_import.find_use_path(db, module_def))
+            .filter(|use_path| !use_path.segments.is_empty())
+            .take(20)
+            .collect::<BTreeSet<_>>()
+    }
+
+    fn assoc_to_trait(assoc: AssocItemContainer) -> Option<Trait> {
+        if let AssocItemContainer::Trait(extracted_trait) = assoc {
+            Some(extracted_trait)
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug)]
+enum ImportCandidate {
+    /// Simple name like 'HashMap'
+    UnqualifiedName(String),
+    /// First part of the qualified name.
+    /// For 'std::collections::HashMap', that will be 'std'.
+    QualifierStart(String),
+    /// A trait associated function (with no self parameter) or associated constant.
+    /// For 'test_mod::TestEnum::test_function', `Type` is the `test_mod::TestEnum` expression type
+    /// and `String` is the `test_function`
+    TraitAssocItem(Type, String),
+    /// A trait method with self parameter.
+    /// For 'test_enum.test_method()', `Type` is the `test_enum` expression type
+    /// and `String` is the `test_method`
+    TraitMethod(Type, String),
+}
+
+impl ImportCandidate {
+    fn for_method_call(
+        method_call: &ast::MethodCallExpr,
+        source_analyzer: &SourceAnalyzer,
+        db: &impl HirDatabase,
+    ) -> Option<Self> {
+        if source_analyzer.resolve_method_call(method_call).is_some() {
+            return None;
+        }
+        Some(Self::TraitMethod(
+            source_analyzer.type_of(db, &method_call.expr()?)?,
+            method_call.name_ref()?.syntax().to_string(),
+        ))
+    }
+
+    fn for_regular_path(
+        path_under_caret: &ast::Path,
+        source_analyzer: &SourceAnalyzer,
+        db: &impl HirDatabase,
+    ) -> Option<Self> {
+        if source_analyzer.resolve_path(db, path_under_caret).is_some() {
+            return None;
+        }
+
+        let segment = path_under_caret.segment()?;
+        if let Some(qualifier) = path_under_caret.qualifier() {
+            let qualifier_start = qualifier.syntax().descendants().find_map(ast::NameRef::cast)?;
+            let qualifier_start_path =
+                qualifier_start.syntax().ancestors().find_map(ast::Path::cast)?;
+            if let Some(qualifier_start_resolution) =
+                source_analyzer.resolve_path(db, &qualifier_start_path)
+            {
+                let qualifier_resolution = if qualifier_start_path == qualifier {
+                    qualifier_start_resolution
+                } else {
+                    source_analyzer.resolve_path(db, &qualifier)?
+                };
+                if let PathResolution::Def(ModuleDef::Adt(assoc_item_path)) = qualifier_resolution {
+                    Some(ImportCandidate::TraitAssocItem(
+                        assoc_item_path.ty(db),
+                        segment.syntax().to_string(),
+                    ))
+                } else {
+                    None
+                }
+            } else {
+                Some(ImportCandidate::QualifierStart(qualifier_start.syntax().to_string()))
+            }
+        } else {
+            Some(ImportCandidate::UnqualifiedName(
+                segment.syntax().descendants().find_map(ast::NameRef::cast)?.syntax().to_string(),
+            ))
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
-    use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
-
     use super::*;
+    use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target};
 
     #[test]
     fn applicable_when_found_an_import() {
@@ -290,4 +491,303 @@ mod tests {
             ",
         );
     }
+
+    #[test]
+    fn not_applicable_for_imported_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            pub mod test_mod {
+                pub fn test_function() {}
+            }
+
+            use test_mod::test_function;
+            fn main() {
+                test_function<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function<|>
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    pub fn test_function() {}
+                }
+            }
+
+            fn main() {
+                TestStruct::test_function<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_struct_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST<|>
+            }
+            ",
+            r"
+            use test_mod::TestStruct;
+
+            mod test_mod {
+                pub struct TestStruct {}
+                impl TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                TestStruct::TEST_CONST<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn associated_trait_function() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function<|>
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_function() {}
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::test_function<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_function() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_function();
+                }
+                pub trait TestTrait2 {
+                    fn test_function();
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_function() {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_function() {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::test_function<|>;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn associated_trait_const() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST<|>
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            fn main() {
+                test_mod::TestStruct::TEST_CONST<|>
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_const() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    const TEST_CONST: u8;
+                }
+                pub trait TestTrait2 {
+                    const TEST_CONST: f64;
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    const TEST_CONST: f64 = 42.0;
+                }
+                impl TestTrait for TestEnum {
+                    const TEST_CONST: u8 = 42;
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                test_mod::TestEnum::TEST_CONST<|>;
+            }
+            ",
+        )
+    }
+
+    #[test]
+    fn trait_method() {
+        check_assist(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth<|>od()
+            }
+            ",
+            r"
+            use test_mod::TestTrait;
+
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub struct TestStruct {}
+                impl TestTrait for TestStruct {
+                    fn test_method(&self) {}
+                }
+            }
+
+            fn main() {
+                let test_struct = test_mod::TestStruct {};
+                test_struct.test_meth<|>od()
+            }
+            ",
+        );
+    }
+
+    #[test]
+    fn not_applicable_for_imported_trait_for_method() {
+        check_assist_not_applicable(
+            auto_import,
+            r"
+            mod test_mod {
+                pub trait TestTrait {
+                    fn test_method(&self);
+                }
+                pub trait TestTrait2 {
+                    fn test_method(&self);
+                }
+                pub enum TestEnum {
+                    One,
+                    Two,
+                }
+                impl TestTrait2 for TestEnum {
+                    fn test_method(&self) {}
+                }
+                impl TestTrait for TestEnum {
+                    fn test_method(&self) {}
+                }
+            }
+
+            use test_mod::TestTrait2;
+            fn main() {
+                let one = test_mod::TestEnum::One;
+                one.test<|>_method();
+            }
+            ",
+        )
+    }
 }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 4fb679f6d..a56b8ab04 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -818,7 +818,7 @@ impl TypeParam {
     }
 }
 
-// FIXME: rename to `ImplBlock`
+// FIXME: rename from `ImplBlock` to `Impl`
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ImplBlock {
     pub(crate) id: ImplId,
diff --git a/crates/ra_hir_def/src/resolver.rs b/crates/ra_hir_def/src/resolver.rs
index 05cf4646a..e2b228e80 100644
--- a/crates/ra_hir_def/src/resolver.rs
+++ b/crates/ra_hir_def/src/resolver.rs
@@ -542,11 +542,7 @@ impl Resolver {
 
     fn push_generic_params_scope(self, db: &impl DefDatabase, def: GenericDefId) -> Resolver {
         let params = db.generic_params(def);
-        if params.types.is_empty() {
-            self
-        } else {
-            self.push_scope(Scope::GenericParams { def, params })
-        }
+        self.push_scope(Scope::GenericParams { def, params })
     }
 
     fn push_impl_block_scope(self, impl_block: ImplId) -> Resolver {
diff --git a/crates/ra_hir_ty/src/display.rs b/crates/ra_hir_ty/src/display.rs
index d1ff85f0f..14e089cf4 100644
--- a/crates/ra_hir_ty/src/display.rs
+++ b/crates/ra_hir_ty/src/display.rs
@@ -2,7 +2,12 @@
 
 use std::fmt;
 
-use crate::db::HirDatabase;
+use crate::{
+    db::HirDatabase, utils::generics, ApplicationTy, CallableDef, FnSig, GenericPredicate,
+    Obligation, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
+};
+use hir_def::{generics::TypeParamProvenance, AdtId, AssocContainerId, Lookup};
+use hir_expand::name::Name;
 
 pub struct HirFormatter<'a, 'b, DB> {
     pub db: &'a DB,
@@ -97,3 +102,369 @@ where
         })
     }
 }
+
+const TYPE_HINT_TRUNCATION: &str = "…";
+
+impl HirDisplay for &Ty {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        HirDisplay::hir_fmt(*self, f)
+    }
+}
+
+impl HirDisplay for ApplicationTy {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        if f.should_truncate() {
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        }
+
+        match self.ctor {
+            TypeCtor::Bool => write!(f, "bool")?,
+            TypeCtor::Char => write!(f, "char")?,
+            TypeCtor::Int(t) => write!(f, "{}", t)?,
+            TypeCtor::Float(t) => write!(f, "{}", t)?,
+            TypeCtor::Str => write!(f, "str")?,
+            TypeCtor::Slice => {
+                let t = self.parameters.as_single();
+                write!(f, "[{}]", t.display(f.db))?;
+            }
+            TypeCtor::Array => {
+                let t = self.parameters.as_single();
+                write!(f, "[{}; _]", t.display(f.db))?;
+            }
+            TypeCtor::RawPtr(m) => {
+                let t = self.parameters.as_single();
+                write!(f, "*{}{}", m.as_keyword_for_ptr(), t.display(f.db))?;
+            }
+            TypeCtor::Ref(m) => {
+                let t = self.parameters.as_single();
+                let ty_display = if f.omit_verbose_types() {
+                    t.display_truncated(f.db, f.max_size)
+                } else {
+                    t.display(f.db)
+                };
+                write!(f, "&{}{}", m.as_keyword_for_ref(), ty_display)?;
+            }
+            TypeCtor::Never => write!(f, "!")?,
+            TypeCtor::Tuple { .. } => {
+                let ts = &self.parameters;
+                if ts.len() == 1 {
+                    write!(f, "({},)", ts[0].display(f.db))?;
+                } else {
+                    write!(f, "(")?;
+                    f.write_joined(&*ts.0, ", ")?;
+                    write!(f, ")")?;
+                }
+            }
+            TypeCtor::FnPtr { .. } => {
+                let sig = FnSig::from_fn_ptr_substs(&self.parameters);
+                write!(f, "fn(")?;
+                f.write_joined(sig.params(), ", ")?;
+                write!(f, ") -> {}", sig.ret().display(f.db))?;
+            }
+            TypeCtor::FnDef(def) => {
+                let sig = f.db.callable_item_signature(def).subst(&self.parameters);
+                let name = match def {
+                    CallableDef::FunctionId(ff) => f.db.function_data(ff).name.clone(),
+                    CallableDef::StructId(s) => f.db.struct_data(s).name.clone(),
+                    CallableDef::EnumVariantId(e) => {
+                        let enum_data = f.db.enum_data(e.parent);
+                        enum_data.variants[e.local_id].name.clone()
+                    }
+                };
+                match def {
+                    CallableDef::FunctionId(_) => write!(f, "fn {}", name)?,
+                    CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {
+                        write!(f, "{}", name)?
+                    }
+                }
+                if self.parameters.len() > 0 {
+                    let generics = generics(f.db, def.into());
+                    let (parent_params, self_param, type_params, _impl_trait_params) =
+                        generics.provenance_split();
+                    let total_len = parent_params + self_param + type_params;
+                    // We print all params except implicit impl Trait params. Still a bit weird; should we leave out parent and self?
+                    if total_len > 0 {
+                        write!(f, "<")?;
+                        f.write_joined(&self.parameters.0[..total_len], ", ")?;
+                        write!(f, ">")?;
+                    }
+                }
+                write!(f, "(")?;
+                f.write_joined(sig.params(), ", ")?;
+                write!(f, ") -> {}", sig.ret().display(f.db))?;
+            }
+            TypeCtor::Adt(def_id) => {
+                let name = match def_id {
+                    AdtId::StructId(it) => f.db.struct_data(it).name.clone(),
+                    AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
+                    AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
+                };
+                write!(f, "{}", name)?;
+                if self.parameters.len() > 0 {
+                    write!(f, "<")?;
+
+                    let mut non_default_parameters = Vec::with_capacity(self.parameters.len());
+                    let parameters_to_write = if f.omit_verbose_types() {
+                        match self
+                            .ctor
+                            .as_generic_def()
+                            .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
+                            .filter(|defaults| !defaults.is_empty())
+                        {
+                            Option::None => self.parameters.0.as_ref(),
+                            Option::Some(default_parameters) => {
+                                for (i, parameter) in self.parameters.iter().enumerate() {
+                                    match (parameter, default_parameters.get(i)) {
+                                        (&Ty::Unknown, _) | (_, None) => {
+                                            non_default_parameters.push(parameter.clone())
+                                        }
+                                        (_, Some(default_parameter))
+                                            if parameter != default_parameter =>
+                                        {
+                                            non_default_parameters.push(parameter.clone())
+                                        }
+                                        _ => (),
+                                    }
+                                }
+                                &non_default_parameters
+                            }
+                        }
+                    } else {
+                        self.parameters.0.as_ref()
+                    };
+
+                    f.write_joined(parameters_to_write, ", ")?;
+                    write!(f, ">")?;
+                }
+            }
+            TypeCtor::AssociatedType(type_alias) => {
+                let trait_ = match type_alias.lookup(f.db).container {
+                    AssocContainerId::TraitId(it) => it,
+                    _ => panic!("not an associated type"),
+                };
+                let trait_name = f.db.trait_data(trait_).name.clone();
+                let name = f.db.type_alias_data(type_alias).name.clone();
+                write!(f, "{}::{}", trait_name, name)?;
+                if self.parameters.len() > 0 {
+                    write!(f, "<")?;
+                    f.write_joined(&*self.parameters.0, ", ")?;
+                    write!(f, ">")?;
+                }
+            }
+            TypeCtor::Closure { .. } => {
+                let sig = self.parameters[0]
+                    .callable_sig(f.db)
+                    .expect("first closure parameter should contain signature");
+                let return_type_hint = sig.ret().display(f.db);
+                if sig.params().is_empty() {
+                    write!(f, "|| -> {}", return_type_hint)?;
+                } else if f.omit_verbose_types() {
+                    write!(f, "|{}| -> {}", TYPE_HINT_TRUNCATION, return_type_hint)?;
+                } else {
+                    write!(f, "|")?;
+                    f.write_joined(sig.params(), ", ")?;
+                    write!(f, "| -> {}", return_type_hint)?;
+                };
+            }
+        }
+        Ok(())
+    }
+}
+
+impl HirDisplay for ProjectionTy {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        if f.should_truncate() {
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        }
+
+        let trait_name = f.db.trait_data(self.trait_(f.db)).name.clone();
+        write!(f, "<{} as {}", self.parameters[0].display(f.db), trait_name,)?;
+        if self.parameters.len() > 1 {
+            write!(f, "<")?;
+            f.write_joined(&self.parameters[1..], ", ")?;
+            write!(f, ">")?;
+        }
+        write!(f, ">::{}", f.db.type_alias_data(self.associated_ty).name)?;
+        Ok(())
+    }
+}
+
+impl HirDisplay for Ty {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        if f.should_truncate() {
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        }
+
+        match self {
+            Ty::Apply(a_ty) => a_ty.hir_fmt(f)?,
+            Ty::Projection(p_ty) => p_ty.hir_fmt(f)?,
+            Ty::Placeholder(id) => {
+                let generics = generics(f.db, id.parent);
+                let param_data = &generics.params.types[id.local_id];
+                match param_data.provenance {
+                    TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
+                        write!(f, "{}", param_data.name.clone().unwrap_or_else(Name::missing))?
+                    }
+                    TypeParamProvenance::ArgumentImplTrait => {
+                        write!(f, "impl ")?;
+                        let bounds = f.db.generic_predicates_for_param(*id);
+                        let substs = Substs::type_params_for_generics(&generics);
+                        write_bounds_like_dyn_trait(
+                            &bounds.iter().map(|b| b.clone().subst(&substs)).collect::<Vec<_>>(),
+                            f,
+                        )?;
+                    }
+                }
+            }
+            Ty::Bound(idx) => write!(f, "?{}", idx)?,
+            Ty::Dyn(predicates) | Ty::Opaque(predicates) => {
+                match self {
+                    Ty::Dyn(_) => write!(f, "dyn ")?,
+                    Ty::Opaque(_) => write!(f, "impl ")?,
+                    _ => unreachable!(),
+                };
+                write_bounds_like_dyn_trait(&predicates, f)?;
+            }
+            Ty::Unknown => write!(f, "{{unknown}}")?,
+            Ty::Infer(..) => write!(f, "_")?,
+        }
+        Ok(())
+    }
+}
+
+fn write_bounds_like_dyn_trait(
+    predicates: &[GenericPredicate],
+    f: &mut HirFormatter<impl HirDatabase>,
+) -> fmt::Result {
+    // Note: This code is written to produce nice results (i.e.
+    // corresponding to surface Rust) for types that can occur in
+    // actual Rust. It will have weird results if the predicates
+    // aren't as expected (i.e. self types = $0, projection
+    // predicates for a certain trait come after the Implemented
+    // predicate for that trait).
+    let mut first = true;
+    let mut angle_open = false;
+    for p in predicates.iter() {
+        match p {
+            GenericPredicate::Implemented(trait_ref) => {
+                if angle_open {
+                    write!(f, ">")?;
+                }
+                if !first {
+                    write!(f, " + ")?;
+                }
+                // We assume that the self type is $0 (i.e. the
+                // existential) here, which is the only thing that's
+                // possible in actual Rust, and hence don't print it
+                write!(f, "{}", f.db.trait_data(trait_ref.trait_).name.clone())?;
+                if trait_ref.substs.len() > 1 {
+                    write!(f, "<")?;
+                    f.write_joined(&trait_ref.substs[1..], ", ")?;
+                    // there might be assoc type bindings, so we leave the angle brackets open
+                    angle_open = true;
+                }
+            }
+            GenericPredicate::Projection(projection_pred) => {
+                // in types in actual Rust, these will always come
+                // after the corresponding Implemented predicate
+                if angle_open {
+                    write!(f, ", ")?;
+                } else {
+                    write!(f, "<")?;
+                    angle_open = true;
+                }
+                let name =
+                    f.db.type_alias_data(projection_pred.projection_ty.associated_ty).name.clone();
+                write!(f, "{} = ", name)?;
+                projection_pred.ty.hir_fmt(f)?;
+            }
+            GenericPredicate::Error => {
+                if angle_open {
+                    // impl Trait<X, {error}>
+                    write!(f, ", ")?;
+                } else if !first {
+                    // impl Trait + {error}
+                    write!(f, " + ")?;
+                }
+                p.hir_fmt(f)?;
+            }
+        }
+        first = false;
+    }
+    if angle_open {
+        write!(f, ">")?;
+    }
+    Ok(())
+}
+
+impl TraitRef {
+    fn hir_fmt_ext(&self, f: &mut HirFormatter<impl HirDatabase>, use_as: bool) -> fmt::Result {
+        if f.should_truncate() {
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        }
+
+        self.substs[0].hir_fmt(f)?;
+        if use_as {
+            write!(f, " as ")?;
+        } else {
+            write!(f, ": ")?;
+        }
+        write!(f, "{}", f.db.trait_data(self.trait_).name.clone())?;
+        if self.substs.len() > 1 {
+            write!(f, "<")?;
+            f.write_joined(&self.substs[1..], ", ")?;
+            write!(f, ">")?;
+        }
+        Ok(())
+    }
+}
+
+impl HirDisplay for TraitRef {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        self.hir_fmt_ext(f, false)
+    }
+}
+
+impl HirDisplay for &GenericPredicate {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        HirDisplay::hir_fmt(*self, f)
+    }
+}
+
+impl HirDisplay for GenericPredicate {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        if f.should_truncate() {
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
+        }
+
+        match self {
+            GenericPredicate::Implemented(trait_ref) => trait_ref.hir_fmt(f)?,
+            GenericPredicate::Projection(projection_pred) => {
+                write!(f, "<")?;
+                projection_pred.projection_ty.trait_ref(f.db).hir_fmt_ext(f, true)?;
+                write!(
+                    f,
+                    ">::{} = {}",
+                    f.db.type_alias_data(projection_pred.projection_ty.associated_ty).name,
+                    projection_pred.ty.display(f.db)
+                )?;
+            }
+            GenericPredicate::Error => write!(f, "{{error}}")?,
+        }
+        Ok(())
+    }
+}
+
+impl HirDisplay for Obligation {
+    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
+        match self {
+            Obligation::Trait(tr) => write!(f, "Implements({})", tr.display(f.db)),
+            Obligation::Projection(proj) => write!(
+                f,
+                "Normalize({} => {})",
+                proj.projection_ty.display(f.db),
+                proj.ty.display(f.db)
+            ),
+        }
+    }
+}
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index c5fe18c85..571579cc4 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -41,13 +41,12 @@ mod marks;
 
 use std::ops::Deref;
 use std::sync::Arc;
-use std::{fmt, iter, mem};
+use std::{iter, mem};
 
 use hir_def::{
-    expr::ExprId, generics::TypeParamProvenance, type_ref::Mutability, AdtId, AssocContainerId,
-    DefWithBodyId, GenericDefId, HasModule, Lookup, TraitId, TypeAliasId, TypeParamId,
+    expr::ExprId, type_ref::Mutability, AdtId, AssocContainerId, DefWithBodyId, GenericDefId,
+    HasModule, Lookup, TraitId, TypeAliasId, TypeParamId,
 };
-use hir_expand::name::Name;
 use ra_db::{impl_intern_key, salsa, CrateId};
 
 use crate::{
@@ -55,7 +54,7 @@ use crate::{
     primitive::{FloatTy, IntTy, Uncertain},
     utils::{generics, make_mut_slice, Generics},
 };
-use display::{HirDisplay, HirFormatter};
+use display::HirDisplay;
 
 pub use autoderef::autoderef;
 pub use infer::{do_infer_query, InferTy, InferenceResult};
@@ -291,7 +290,7 @@ pub enum Ty {
     /// {}` when we're type-checking the body of that function. In this
     /// situation, we know this stands for *some* type, but don't know the exact
     /// type.
-    Param(TypeParamId),
+    Placeholder(TypeParamId),
 
     /// A bound type variable. This is used in various places: when representing
     /// some polymorphic type like the type of function `fn f<T>`, the type
@@ -365,7 +364,7 @@ impl Substs {
 
     /// Return Substs that replace each parameter by itself (i.e. `Ty::Param`).
     pub(crate) fn type_params_for_generics(generic_params: &Generics) -> Substs {
-        Substs(generic_params.iter().map(|(id, _)| Ty::Param(id)).collect())
+        Substs(generic_params.iter().map(|(id, _)| Ty::Placeholder(id)).collect())
     }
 
     /// Return Substs that replace each parameter by itself (i.e. `Ty::Param`).
@@ -813,7 +812,7 @@ impl TypeWalk for Ty {
                     p.walk(f);
                 }
             }
-            Ty::Param { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
+            Ty::Placeholder { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
         }
         f(self);
     }
@@ -831,374 +830,8 @@ impl TypeWalk for Ty {
                     p.walk_mut_binders(f, binders + 1);
                 }
             }
-            Ty::Param { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
+            Ty::Placeholder { .. } | Ty::Bound(_) | Ty::Infer(_) | Ty::Unknown => {}
         }
         f(self, binders);
     }
 }
-
-const TYPE_HINT_TRUNCATION: &str = "…";
-
-impl HirDisplay for &Ty {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        HirDisplay::hir_fmt(*self, f)
-    }
-}
-
-impl HirDisplay for ApplicationTy {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
-        }
-
-        match self.ctor {
-            TypeCtor::Bool => write!(f, "bool")?,
-            TypeCtor::Char => write!(f, "char")?,
-            TypeCtor::Int(t) => write!(f, "{}", t)?,
-            TypeCtor::Float(t) => write!(f, "{}", t)?,
-            TypeCtor::Str => write!(f, "str")?,
-            TypeCtor::Slice => {
-                let t = self.parameters.as_single();
-                write!(f, "[{}]", t.display(f.db))?;
-            }
-            TypeCtor::Array => {
-                let t = self.parameters.as_single();
-                write!(f, "[{}; _]", t.display(f.db))?;
-            }
-            TypeCtor::RawPtr(m) => {
-                let t = self.parameters.as_single();
-                write!(f, "*{}{}", m.as_keyword_for_ptr(), t.display(f.db))?;
-            }
-            TypeCtor::Ref(m) => {
-                let t = self.parameters.as_single();
-                let ty_display = if f.omit_verbose_types() {
-                    t.display_truncated(f.db, f.max_size)
-                } else {
-                    t.display(f.db)
-                };
-                write!(f, "&{}{}", m.as_keyword_for_ref(), ty_display)?;
-            }
-            TypeCtor::Never => write!(f, "!")?,
-            TypeCtor::Tuple { .. } => {
-                let ts = &self.parameters;
-                if ts.len() == 1 {
-                    write!(f, "({},)", ts[0].display(f.db))?;
-                } else {
-                    write!(f, "(")?;
-                    f.write_joined(&*ts.0, ", ")?;
-                    write!(f, ")")?;
-                }
-            }
-            TypeCtor::FnPtr { .. } => {
-                let sig = FnSig::from_fn_ptr_substs(&self.parameters);
-                write!(f, "fn(")?;
-                f.write_joined(sig.params(), ", ")?;
-                write!(f, ") -> {}", sig.ret().display(f.db))?;
-            }
-            TypeCtor::FnDef(def) => {
-                let sig = f.db.callable_item_signature(def).subst(&self.parameters);
-                let name = match def {
-                    CallableDef::FunctionId(ff) => f.db.function_data(ff).name.clone(),
-                    CallableDef::StructId(s) => f.db.struct_data(s).name.clone(),
-                    CallableDef::EnumVariantId(e) => {
-                        let enum_data = f.db.enum_data(e.parent);
-                        enum_data.variants[e.local_id].name.clone()
-                    }
-                };
-                match def {
-                    CallableDef::FunctionId(_) => write!(f, "fn {}", name)?,
-                    CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {
-                        write!(f, "{}", name)?
-                    }
-                }
-                if self.parameters.len() > 0 {
-                    let generics = generics(f.db, def.into());
-                    let (parent_params, self_param, type_params, _impl_trait_params) =
-                        generics.provenance_split();
-                    let total_len = parent_params + self_param + type_params;
-                    // We print all params except implicit impl Trait params. Still a bit weird; should we leave out parent and self?
-                    if total_len > 0 {
-                        write!(f, "<")?;
-                        f.write_joined(&self.parameters.0[..total_len], ", ")?;
-                        write!(f, ">")?;
-                    }
-                }
-                write!(f, "(")?;
-                f.write_joined(sig.params(), ", ")?;
-                write!(f, ") -> {}", sig.ret().display(f.db))?;
-            }
-            TypeCtor::Adt(def_id) => {
-                let name = match def_id {
-                    AdtId::StructId(it) => f.db.struct_data(it).name.clone(),
-                    AdtId::UnionId(it) => f.db.union_data(it).name.clone(),
-                    AdtId::EnumId(it) => f.db.enum_data(it).name.clone(),
-                };
-                write!(f, "{}", name)?;
-                if self.parameters.len() > 0 {
-                    write!(f, "<")?;
-
-                    let mut non_default_parameters = Vec::with_capacity(self.parameters.len());
-                    let parameters_to_write = if f.omit_verbose_types() {
-                        match self
-                            .ctor
-                            .as_generic_def()
-                            .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
-                            .filter(|defaults| !defaults.is_empty())
-                        {
-                            Option::None => self.parameters.0.as_ref(),
-                            Option::Some(default_parameters) => {
-                                for (i, parameter) in self.parameters.iter().enumerate() {
-                                    match (parameter, default_parameters.get(i)) {
-                                        (&Ty::Unknown, _) | (_, None) => {
-                                            non_default_parameters.push(parameter.clone())
-                                        }
-                                        (_, Some(default_parameter))
-                                            if parameter != default_parameter =>
-                                        {
-                                            non_default_parameters.push(parameter.clone())
-                                        }
-                                        _ => (),
-                                    }
-                                }
-                                &non_default_parameters
-                            }
-                        }
-                    } else {
-                        self.parameters.0.as_ref()
-                    };
-
-                    f.write_joined(parameters_to_write, ", ")?;
-                    write!(f, ">")?;
-                }
-            }
-            TypeCtor::AssociatedType(type_alias) => {
-                let trait_ = match type_alias.lookup(f.db).container {
-                    AssocContainerId::TraitId(it) => it,
-                    _ => panic!("not an associated type"),
-                };
-                let trait_name = f.db.trait_data(trait_).name.clone();
-                let name = f.db.type_alias_data(type_alias).name.clone();
-                write!(f, "{}::{}", trait_name, name)?;
-                if self.parameters.len() > 0 {
-                    write!(f, "<")?;
-                    f.write_joined(&*self.parameters.0, ", ")?;
-                    write!(f, ">")?;
-                }
-            }
-            TypeCtor::Closure { .. } => {
-                let sig = self.parameters[0]
-                    .callable_sig(f.db)
-                    .expect("first closure parameter should contain signature");
-                let return_type_hint = sig.ret().display(f.db);
-                if sig.params().is_empty() {
-                    write!(f, "|| -> {}", return_type_hint)?;
-                } else if f.omit_verbose_types() {
-                    write!(f, "|{}| -> {}", TYPE_HINT_TRUNCATION, return_type_hint)?;
-                } else {
-                    write!(f, "|")?;
-                    f.write_joined(sig.params(), ", ")?;
-                    write!(f, "| -> {}", return_type_hint)?;
-                };
-            }
-        }
-        Ok(())
-    }
-}
-
-impl HirDisplay for ProjectionTy {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
-        }
-
-        let trait_name = f.db.trait_data(self.trait_(f.db)).name.clone();
-        write!(f, "<{} as {}", self.parameters[0].display(f.db), trait_name,)?;
-        if self.parameters.len() > 1 {
-            write!(f, "<")?;
-            f.write_joined(&self.parameters[1..], ", ")?;
-            write!(f, ">")?;
-        }
-        write!(f, ">::{}", f.db.type_alias_data(self.associated_ty).name)?;
-        Ok(())
-    }
-}
-
-impl HirDisplay for Ty {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
-        }
-
-        match self {
-            Ty::Apply(a_ty) => a_ty.hir_fmt(f)?,
-            Ty::Projection(p_ty) => p_ty.hir_fmt(f)?,
-            Ty::Param(id) => {
-                let generics = generics(f.db, id.parent);
-                let param_data = &generics.params.types[id.local_id];
-                match param_data.provenance {
-                    TypeParamProvenance::TypeParamList | TypeParamProvenance::TraitSelf => {
-                        write!(f, "{}", param_data.name.clone().unwrap_or_else(Name::missing))?
-                    }
-                    TypeParamProvenance::ArgumentImplTrait => {
-                        write!(f, "impl ")?;
-                        let bounds = f.db.generic_predicates_for_param(*id);
-                        let substs = Substs::type_params_for_generics(&generics);
-                        write_bounds_like_dyn_trait(
-                            &bounds.iter().map(|b| b.clone().subst(&substs)).collect::<Vec<_>>(),
-                            f,
-                        )?;
-                    }
-                }
-            }
-            Ty::Bound(idx) => write!(f, "?{}", idx)?,
-            Ty::Dyn(predicates) | Ty::Opaque(predicates) => {
-                match self {
-                    Ty::Dyn(_) => write!(f, "dyn ")?,
-                    Ty::Opaque(_) => write!(f, "impl ")?,
-                    _ => unreachable!(),
-                };
-                write_bounds_like_dyn_trait(&predicates, f)?;
-            }
-            Ty::Unknown => write!(f, "{{unknown}}")?,
-            Ty::Infer(..) => write!(f, "_")?,
-        }
-        Ok(())
-    }
-}
-
-fn write_bounds_like_dyn_trait(
-    predicates: &[GenericPredicate],
-    f: &mut HirFormatter<impl HirDatabase>,
-) -> fmt::Result {
-    // Note: This code is written to produce nice results (i.e.
-    // corresponding to surface Rust) for types that can occur in
-    // actual Rust. It will have weird results if the predicates
-    // aren't as expected (i.e. self types = $0, projection
-    // predicates for a certain trait come after the Implemented
-    // predicate for that trait).
-    let mut first = true;
-    let mut angle_open = false;
-    for p in predicates.iter() {
-        match p {
-            GenericPredicate::Implemented(trait_ref) => {
-                if angle_open {
-                    write!(f, ">")?;
-                }
-                if !first {
-                    write!(f, " + ")?;
-                }
-                // We assume that the self type is $0 (i.e. the
-                // existential) here, which is the only thing that's
-                // possible in actual Rust, and hence don't print it
-                write!(f, "{}", f.db.trait_data(trait_ref.trait_).name.clone())?;
-                if trait_ref.substs.len() > 1 {
-                    write!(f, "<")?;
-                    f.write_joined(&trait_ref.substs[1..], ", ")?;
-                    // there might be assoc type bindings, so we leave the angle brackets open
-                    angle_open = true;
-                }
-            }
-            GenericPredicate::Projection(projection_pred) => {
-                // in types in actual Rust, these will always come
-                // after the corresponding Implemented predicate
-                if angle_open {
-                    write!(f, ", ")?;
-                } else {
-                    write!(f, "<")?;
-                    angle_open = true;
-                }
-                let name =
-                    f.db.type_alias_data(projection_pred.projection_ty.associated_ty).name.clone();
-                write!(f, "{} = ", name)?;
-                projection_pred.ty.hir_fmt(f)?;
-            }
-            GenericPredicate::Error => {
-                if angle_open {
-                    // impl Trait<X, {error}>
-                    write!(f, ", ")?;
-                } else if !first {
-                    // impl Trait + {error}
-                    write!(f, " + ")?;
-                }
-                p.hir_fmt(f)?;
-            }
-        }
-        first = false;
-    }
-    if angle_open {
-        write!(f, ">")?;
-    }
-    Ok(())
-}
-
-impl TraitRef {
-    fn hir_fmt_ext(&self, f: &mut HirFormatter<impl HirDatabase>, use_as: bool) -> fmt::Result {
-        if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
-        }
-
-        self.substs[0].hir_fmt(f)?;
-        if use_as {
-            write!(f, " as ")?;
-        } else {
-            write!(f, ": ")?;
-        }
-        write!(f, "{}", f.db.trait_data(self.trait_).name.clone())?;
-        if self.substs.len() > 1 {
-            write!(f, "<")?;
-            f.write_joined(&self.substs[1..], ", ")?;
-            write!(f, ">")?;
-        }
-        Ok(())
-    }
-}
-
-impl HirDisplay for TraitRef {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        self.hir_fmt_ext(f, false)
-    }
-}
-
-impl HirDisplay for &GenericPredicate {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        HirDisplay::hir_fmt(*self, f)
-    }
-}
-
-impl HirDisplay for GenericPredicate {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        if f.should_truncate() {
-            return write!(f, "{}", TYPE_HINT_TRUNCATION);
-        }
-
-        match self {
-            GenericPredicate::Implemented(trait_ref) => trait_ref.hir_fmt(f)?,
-            GenericPredicate::Projection(projection_pred) => {
-                write!(f, "<")?;
-                projection_pred.projection_ty.trait_ref(f.db).hir_fmt_ext(f, true)?;
-                write!(
-                    f,
-                    ">::{} = {}",
-                    f.db.type_alias_data(projection_pred.projection_ty.associated_ty).name,
-                    projection_pred.ty.display(f.db)
-                )?;
-            }
-            GenericPredicate::Error => write!(f, "{{error}}")?,
-        }
-        Ok(())
-    }
-}
-
-impl HirDisplay for Obligation {
-    fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
-        match self {
-            Obligation::Trait(tr) => write!(f, "Implements({})", tr.display(f.db)),
-            Obligation::Projection(proj) => write!(
-                f,
-                "Normalize({} => {})",
-                proj.projection_ty.display(f.db),
-                proj.ty.display(f.db)
-            ),
-        }
-    }
-}
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index c68c5852b..6a2aded02 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -14,9 +14,9 @@ use hir_def::{
     path::{GenericArg, Path, PathSegment, PathSegments},
     resolver::{HasResolver, Resolver, TypeNs},
     type_ref::{TypeBound, TypeRef},
-    AdtId, ConstId, EnumId, EnumVariantId, FunctionId, GenericDefId, HasModule, ImplId,
-    LocalStructFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId, TypeParamId, UnionId,
-    VariantId,
+    AdtId, AssocContainerId, ConstId, EnumId, EnumVariantId, FunctionId, GenericDefId, HasModule,
+    ImplId, LocalStructFieldId, Lookup, StaticId, StructId, TraitId, TypeAliasId, TypeParamId,
+    UnionId, VariantId,
 };
 use ra_arena::map::ArenaMap;
 use ra_db::CrateId;
@@ -152,7 +152,7 @@ impl Ty {
                                     data.provenance == TypeParamProvenance::ArgumentImplTrait
                                 })
                                 .nth(idx as usize)
-                                .map_or(Ty::Unknown, |(id, _)| Ty::Param(id));
+                                .map_or(Ty::Unknown, |(id, _)| Ty::Placeholder(id));
                             param
                         } else {
                             Ty::Unknown
@@ -270,7 +270,7 @@ impl Ty {
                 let generics =
                     generics(ctx.db, ctx.resolver.generic_def().expect("generics in scope"));
                 match ctx.type_param_mode {
-                    TypeParamLoweringMode::Placeholder => Ty::Param(param_id),
+                    TypeParamLoweringMode::Placeholder => Ty::Placeholder(param_id),
                     TypeParamLoweringMode::Variable => {
                         let idx = generics.param_idx(param_id).expect("matching generics");
                         Ty::Bound(idx)
@@ -339,7 +339,7 @@ impl Ty {
             None => return Ty::Unknown, // this can't actually happen
         };
         let param_id = match self_ty {
-            Ty::Param(id) if ctx.type_param_mode == TypeParamLoweringMode::Placeholder => id,
+            Ty::Placeholder(id) if ctx.type_param_mode == TypeParamLoweringMode::Placeholder => id,
             Ty::Bound(idx) if ctx.type_param_mode == TypeParamLoweringMode::Variable => {
                 let generics = generics(ctx.db, def);
                 let param_id = if let Some((id, _)) = generics.iter().nth(idx as usize) {
@@ -544,7 +544,7 @@ impl GenericPredicate {
                 let generics = generics(ctx.db, generic_def);
                 let param_id = hir_def::TypeParamId { parent: generic_def, local_id: *param_id };
                 match ctx.type_param_mode {
-                    TypeParamLoweringMode::Placeholder => Ty::Param(param_id),
+                    TypeParamLoweringMode::Placeholder => Ty::Placeholder(param_id),
                     TypeParamLoweringMode::Variable => {
                         let idx = generics.param_idx(param_id).expect("matching generics");
                         Ty::Bound(idx)
@@ -672,11 +672,35 @@ impl TraitEnvironment {
     pub fn lower(db: &impl HirDatabase, resolver: &Resolver) -> Arc<TraitEnvironment> {
         let ctx = TyLoweringContext::new(db, &resolver)
             .with_type_param_mode(TypeParamLoweringMode::Placeholder);
-        let predicates = resolver
+        let mut predicates = resolver
             .where_predicates_in_scope()
             .flat_map(|pred| GenericPredicate::from_where_predicate(&ctx, pred))
             .collect::<Vec<_>>();
 
+        if let Some(def) = resolver.generic_def() {
+            let container: Option<AssocContainerId> = match def {
+                // FIXME: is there a function for this?
+                GenericDefId::FunctionId(f) => Some(f.lookup(db).container),
+                GenericDefId::AdtId(_) => None,
+                GenericDefId::TraitId(_) => None,
+                GenericDefId::TypeAliasId(t) => Some(t.lookup(db).container),
+                GenericDefId::ImplId(_) => None,
+                GenericDefId::EnumVariantId(_) => None,
+                GenericDefId::ConstId(c) => Some(c.lookup(db).container),
+            };
+            if let Some(AssocContainerId::TraitId(trait_id)) = container {
+                // add `Self: Trait<T1, T2, ...>` to the environment in trait
+                // function default implementations (and hypothetical code
+                // inside consts or type aliases)
+                test_utils::tested_by!(trait_self_implements_self);
+                let substs = Substs::type_params(db, trait_id);
+                let trait_ref = TraitRef { trait_: trait_id, substs };
+                let pred = GenericPredicate::Implemented(trait_ref);
+
+                predicates.push(pred);
+            }
+        }
+
         Arc::new(TraitEnvironment { predicates })
     }
 }
diff --git a/crates/ra_hir_ty/src/marks.rs b/crates/ra_hir_ty/src/marks.rs
index 0f754eb9c..de5cb1d6b 100644
--- a/crates/ra_hir_ty/src/marks.rs
+++ b/crates/ra_hir_ty/src/marks.rs
@@ -4,6 +4,8 @@ test_utils::marks!(
     type_var_cycles_resolve_completely
     type_var_cycles_resolve_as_possible
     type_var_resolves_to_int_var
+    impl_self_type_match_without_receiver
     match_ergonomics_ref
     coerce_merge_fail_fallback
+    trait_self_implements_self
 );
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 5283bff28..4f8c52433 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -425,6 +425,15 @@ fn iterate_inherent_methods<T>(
                 if !is_valid_candidate(db, name, receiver_ty, item, self_ty) {
                     continue;
                 }
+                // we have to check whether the self type unifies with the type
+                // that the impl is for. If we have a receiver type, this
+                // already happens in `is_valid_candidate` above; if not, we
+                // check it here
+                if receiver_ty.is_none() && inherent_impl_substs(db, impl_block, self_ty).is_none()
+                {
+                    test_utils::tested_by!(impl_self_type_match_without_receiver);
+                    continue;
+                }
                 if let Some(result) = callback(&self_ty.value, item) {
                     return Some(result);
                 }
diff --git a/crates/ra_hir_ty/src/tests/method_resolution.rs b/crates/ra_hir_ty/src/tests/method_resolution.rs
index 1722563aa..1f767d324 100644
--- a/crates/ra_hir_ty/src/tests/method_resolution.rs
+++ b/crates/ra_hir_ty/src/tests/method_resolution.rs
@@ -964,6 +964,38 @@ fn test() { S2.into()<|>; }
 }
 
 #[test]
+fn method_resolution_overloaded_method() {
+    test_utils::covers!(impl_self_type_match_without_receiver);
+    let t = type_at(
+        r#"
+//- main.rs
+struct Wrapper<T>(T);
+struct Foo<T>(T);
+struct Bar<T>(T);
+
+impl<T> Wrapper<Foo<T>> {
+    pub fn new(foo_: T) -> Self {
+        Wrapper(Foo(foo_))
+    }
+}
+
+impl<T> Wrapper<Bar<T>> {
+    pub fn new(bar_: T) -> Self {
+        Wrapper(Bar(bar_))
+    }
+}
+
+fn main() {
+    let a = Wrapper::<Foo<f32>>::new(1.0);
+    let b = Wrapper::<Bar<f32>>::new(1.0);
+    (a, b)<|>;
+}
+"#,
+    );
+    assert_eq!(t, "(Wrapper<Foo<f32>>, Wrapper<Bar<f32>>)")
+}
+
+#[test]
 fn method_resolution_encountering_fn_type() {
     type_at(
         r#"
diff --git a/crates/ra_hir_ty/src/tests/traits.rs b/crates/ra_hir_ty/src/tests/traits.rs
index 17611ddbf..aa2018944 100644
--- a/crates/ra_hir_ty/src/tests/traits.rs
+++ b/crates/ra_hir_ty/src/tests/traits.rs
@@ -300,6 +300,54 @@ fn test() {
 }
 
 #[test]
+fn trait_default_method_self_bound_implements_trait() {
+    test_utils::covers!(trait_self_implements_self);
+    assert_snapshot!(
+        infer(r#"
+trait Trait {
+    fn foo(&self) -> i64;
+    fn bar(&self) -> {
+        let x = self.foo();
+    }
+}
+"#),
+        @r###"
+    [27; 31) 'self': &Self
+    [53; 57) 'self': &Self
+    [62; 97) '{     ...     }': ()
+    [76; 77) 'x': i64
+    [80; 84) 'self': &Self
+    [80; 90) 'self.foo()': i64
+    "###
+    );
+}
+
+#[test]
+fn trait_default_method_self_bound_implements_super_trait() {
+    test_utils::covers!(trait_self_implements_self);
+    assert_snapshot!(
+        infer(r#"
+trait SuperTrait {
+    fn foo(&self) -> i64;
+}
+trait Trait: SuperTrait {
+    fn bar(&self) -> {
+        let x = self.foo();
+    }
+}
+"#),
+        @r###"
+    [32; 36) 'self': &Self
+    [86; 90) 'self': &Self
+    [95; 130) '{     ...     }': ()
+    [109; 110) 'x': i64
+    [113; 117) 'self': &Self
+    [113; 123) 'self.foo()': i64
+    "###
+    );
+}
+
+#[test]
 fn infer_project_associated_type() {
     // y, z, a don't yet work because of https://github.com/rust-lang/chalk/issues/234
     assert_snapshot!(
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index 4974c565b..882160fa8 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -142,7 +142,7 @@ impl ToChalk for Ty {
                 let substitution = proj_ty.parameters.to_chalk(db);
                 chalk_ir::AliasTy { associated_ty_id, substitution }.cast().intern()
             }
-            Ty::Param(id) => {
+            Ty::Placeholder(id) => {
                 let interned_id = db.intern_type_param_id(id);
                 PlaceholderIndex {
                     ui: UniverseIndex::ROOT,
@@ -184,7 +184,7 @@ impl ToChalk for Ty {
                 let interned_id = crate::db::GlobalTypeParamId::from_intern_id(
                     crate::salsa::InternId::from(idx.idx),
                 );
-                Ty::Param(db.lookup_intern_type_param_id(interned_id))
+                Ty::Placeholder(db.lookup_intern_type_param_id(interned_id))
             }
             chalk_ir::TyData::Alias(proj) => {
                 let associated_ty = from_chalk(db, proj.associated_ty_id);
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 59c86bbfa..2e598fdcd 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -758,7 +758,7 @@ pub fn handle_code_lens(
     // Gather runnables
     for runnable in world.analysis().runnables(file_id)? {
         let title = match &runnable.kind {
-            RunnableKind::Test { .. } | RunnableKind::TestMod { .. } => "▶️Run Test",
+            RunnableKind::Test { .. } | RunnableKind::TestMod { .. } => "▶️\u{fe0e}Run Test",
             RunnableKind::Bench { .. } => "Run Bench",
             RunnableKind::Bin => "Run",
         }
diff --git a/crates/ra_parser/src/grammar/params.rs b/crates/ra_parser/src/grammar/params.rs
index ed4f93347..272661b1d 100644
--- a/crates/ra_parser/src/grammar/params.rs
+++ b/crates/ra_parser/src/grammar/params.rs
@@ -114,8 +114,11 @@ fn value_parameter(p: &mut Parser, flavor: Flavor) {
         // test fn_pointer_param_ident_path
         // type Foo = fn(Bar::Baz);
         // type Qux = fn(baz: Bar::Baz);
+
+        // test fn_pointer_unnamed_arg
+        // type Foo = fn(_: bar);
         Flavor::FnPointer => {
-            if p.at(IDENT) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
+            if (p.at(IDENT) || p.at(UNDERSCORE)) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
                 patterns::pattern_single(p);
                 types::ascription(p);
             } else {
diff --git a/crates/ra_project_model/Cargo.toml b/crates/ra_project_model/Cargo.toml
index 69edc3c66..653d5bd14 100644
--- a/crates/ra_project_model/Cargo.toml
+++ b/crates/ra_project_model/Cargo.toml
@@ -19,3 +19,5 @@ ra_cfg = { path = "../ra_cfg" }
 
 serde = { version = "1.0.89", features = ["derive"] }
 serde_json = "1.0.39"
+
+anyhow = "1.0.26"
diff --git a/crates/ra_project_model/src/cargo_workspace.rs b/crates/ra_project_model/src/cargo_workspace.rs
index 60cb8c1eb..22d226a74 100644
--- a/crates/ra_project_model/src/cargo_workspace.rs
+++ b/crates/ra_project_model/src/cargo_workspace.rs
@@ -2,14 +2,13 @@
 
 use std::path::{Path, PathBuf};
 
+use anyhow::{Context, Result};
 use cargo_metadata::{CargoOpt, MetadataCommand};
 use ra_arena::{impl_arena_id, Arena, RawId};
 use ra_db::Edition;
 use rustc_hash::FxHashMap;
 use serde::Deserialize;
 
-use crate::Result;
-
 /// `CargoWorkspace` represents the logical structure of, well, a Cargo
 /// workspace. It pretty closely mirrors `cargo metadata` output.
 ///
@@ -171,7 +170,9 @@ impl CargoWorkspace {
         if let Some(parent) = cargo_toml.parent() {
             meta.current_dir(parent);
         }
-        let meta = meta.exec().map_err(|e| format!("cargo metadata failed: {}", e))?;
+        let meta = meta.exec().with_context(|| {
+            format!("Failed to run `cargo metadata --manifest-path {}`", cargo_toml.display())
+        })?;
         let mut pkg_by_id = FxHashMap::default();
         let mut packages = Arena::default();
         let mut targets = Arena::default();
@@ -181,7 +182,9 @@ impl CargoWorkspace {
         for meta_pkg in meta.packages {
             let cargo_metadata::Package { id, edition, name, manifest_path, .. } = meta_pkg;
             let is_member = ws_members.contains(&id);
-            let edition = edition.parse::<Edition>()?;
+            let edition = edition
+                .parse::<Edition>()
+                .with_context(|| format!("Failed to parse edition {}", edition))?;
             let pkg = packages.alloc(PackageData {
                 name,
                 manifest: manifest_path,
diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index bc1d15406..250255813 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -12,6 +12,7 @@ use std::{
     process::Command,
 };
 
+use anyhow::{bail, Context, Result};
 use ra_cfg::CfgOptions;
 use ra_db::{CrateGraph, CrateId, CrateName, Edition, Env, FileId};
 use rustc_hash::FxHashMap;
@@ -23,8 +24,6 @@ pub use crate::{
     sysroot::Sysroot,
 };
 
-pub type Result<T> = ::std::result::Result<T, Box<dyn Error + Send + Sync>>;
-
 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
 pub struct CargoTomlNotFoundError(pub PathBuf);
 
@@ -81,15 +80,36 @@ impl ProjectWorkspace {
     ) -> Result<ProjectWorkspace> {
         match find_rust_project_json(path) {
             Some(json_path) => {
-                let file = File::open(json_path)?;
+                let file = File::open(&json_path)
+                    .with_context(|| format!("Failed to open json file {}", json_path.display()))?;
                 let reader = BufReader::new(file);
-                Ok(ProjectWorkspace::Json { project: from_reader(reader)? })
+                Ok(ProjectWorkspace::Json {
+                    project: from_reader(reader).with_context(|| {
+                        format!("Failed to deserialize json file {}", json_path.display())
+                    })?,
+                })
             }
             None => {
-                let cargo_toml = find_cargo_toml(path)?;
-                let cargo = CargoWorkspace::from_cargo_metadata(&cargo_toml, cargo_features)?;
-                let sysroot =
-                    if with_sysroot { Sysroot::discover(&cargo_toml)? } else { Sysroot::default() };
+                let cargo_toml = find_cargo_toml(path).with_context(|| {
+                    format!("Failed to find Cargo.toml for path {}", path.display())
+                })?;
+                let cargo = CargoWorkspace::from_cargo_metadata(&cargo_toml, cargo_features)
+                    .with_context(|| {
+                        format!(
+                            "Failed to read Cargo metadata from Cargo.toml file {}",
+                            cargo_toml.display()
+                        )
+                    })?;
+                let sysroot = if with_sysroot {
+                    Sysroot::discover(&cargo_toml).with_context(|| {
+                        format!(
+                            "Failed to find sysroot for Cargo.toml file {}",
+                            cargo_toml.display()
+                        )
+                    })?
+                } else {
+                    Sysroot::default()
+                };
                 Ok(ProjectWorkspace::Cargo { cargo, sysroot })
             }
         }
@@ -398,16 +418,27 @@ pub fn get_rustc_cfg_options() -> CfgOptions {
     // Some nightly-only cfgs, which are required for stdlib
     {
         cfg_options.insert_atom("target_thread_local".into());
-        for &target_has_atomic in ["16", "32", "64", "8", "cas", "ptr"].iter() {
-            cfg_options.insert_key_value("target_has_atomic".into(), target_has_atomic.into())
+        for &target_has_atomic in ["8", "16", "32", "64", "cas", "ptr"].iter() {
+            cfg_options.insert_key_value("target_has_atomic".into(), target_has_atomic.into());
+            cfg_options
+                .insert_key_value("target_has_atomic_load_store".into(), target_has_atomic.into());
         }
     }
 
-    match (|| -> Result<_> {
+    match (|| -> Result<String> {
         // `cfg(test)` and `cfg(debug_assertion)` are handled outside, so we suppress them here.
-        let output = Command::new("rustc").args(&["--print", "cfg", "-O"]).output()?;
+        let output = Command::new("rustc")
+            .args(&["--print", "cfg", "-O"])
+            .output()
+            .context("Failed to get output from rustc --print cfg -O")?;
         if !output.status.success() {
-            Err("failed to get rustc cfgs")?;
+            bail!(
+                "rustc --print cfg -O exited with exit code ({})",
+                output
+                    .status
+                    .code()
+                    .map_or(String::from("no exit code"), |code| format!("{}", code))
+            );
         }
         Ok(String::from_utf8(output.stdout)?)
     })() {
diff --git a/crates/ra_project_model/src/sysroot.rs b/crates/ra_project_model/src/sysroot.rs
index a23265fc0..7b9cc899c 100644
--- a/crates/ra_project_model/src/sysroot.rs
+++ b/crates/ra_project_model/src/sysroot.rs
@@ -1,5 +1,6 @@
 //! FIXME: write short doc here
 
+use anyhow::{anyhow, bail, Context, Result};
 use std::{
     env,
     path::{Path, PathBuf},
@@ -8,8 +9,6 @@ use std::{
 
 use ra_arena::{impl_arena_id, Arena, RawId};
 
-use crate::Result;
-
 #[derive(Default, Debug, Clone)]
 pub struct Sysroot {
     crates: Arena<SysrootCrate, SysrootCrateData>,
@@ -51,7 +50,7 @@ impl Sysroot {
         let src = try_find_src_path(cargo_toml)?;
 
         if !src.exists() {
-            Err(format!(
+            Err(anyhow!(
                 "can't load standard library from sysroot\n\
                  {}\n\
                  (discovered via `rustc --print sysroot`)\n\
@@ -100,9 +99,14 @@ fn try_find_src_path(cargo_toml: &Path) -> Result<PathBuf> {
         .current_dir(cargo_toml.parent().unwrap())
         .args(&["--print", "sysroot"])
         .output()
-        .map_err(|e| format!("rustc --print sysroot failed: {}", e))?;
+        .context("rustc --print sysroot failed")?;
     if !rustc_output.status.success() {
-        Err("failed to locate sysroot")?;
+        match rustc_output.status.code() {
+            Some(code) => {
+                bail!("failed to locate sysroot: rustc --print sysroot exited with code {}", code)
+            }
+            None => bail!("failed to locate sysroot: rustc --print sysroot terminated by signal"),
+        };
     }
     let stdout = String::from_utf8(rustc_output.stdout)?;
     let sysroot_path = Path::new(stdout.trim());
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.rs b/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.rs
new file mode 100644
index 000000000..1ebbe5b03
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.rs
@@ -0,0 +1 @@
+type Foo = fn(_: bar);
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.txt b/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.txt
new file mode 100644
index 000000000..52d8f21a4
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0157_fn_pointer_unnamed_arg.txt
@@ -0,0 +1,26 @@
+SOURCE_FILE@[0; 23)
+  TYPE_ALIAS_DEF@[0; 22)
+    TYPE_KW@[0; 4) "type"
+    WHITESPACE@[4; 5) " "
+    NAME@[5; 8)
+      IDENT@[5; 8) "Foo"
+    WHITESPACE@[8; 9) " "
+    EQ@[9; 10) "="
+    WHITESPACE@[10; 11) " "
+    FN_POINTER_TYPE@[11; 21)
+      FN_KW@[11; 13) "fn"
+      PARAM_LIST@[13; 21)
+        L_PAREN@[13; 14) "("
+        PARAM@[14; 20)
+          PLACEHOLDER_PAT@[14; 15)
+            UNDERSCORE@[14; 15) "_"
+          COLON@[15; 16) ":"
+          WHITESPACE@[16; 17) " "
+          PATH_TYPE@[17; 20)
+            PATH@[17; 20)
+              PATH_SEGMENT@[17; 20)
+                NAME_REF@[17; 20)
+                  IDENT@[17; 20) "bar"
+        R_PAREN@[20; 21) ")"
+    SEMI@[21; 22) ";"
+  WHITESPACE@[22; 23) "\n"
diff --git a/docs/user/README.md b/docs/user/README.md
deleted file mode 100644
index 14ca6fd64..000000000
--- a/docs/user/README.md
+++ /dev/null
@@ -1,280 +0,0 @@
-[github-releases]: https://github.com/rust-analyzer/rust-analyzer/releases
-
-The main interface to rust-analyzer is the
-[LSP](https://microsoft.github.io/language-server-protocol/) implementation. To
-install lsp server, you have three options:
-
-* **Preferred and default:** install the plugin/extension for your IDE and it will ask your permission to automatically download the latest lsp server for you from [GitHub releases][github-releases]. (See docs to find out whether this is implemented for your editor below).
-* Manually download prebuilt binaries from [GitHub releases][github-releases]
-    * `ra_lsp_server-linux` for Linux
-    * `ra_lsp_server-mac` for Mac
-    * `ra_lsp_server-windows.exe` for Windows
-* Clone the repository and build from sources
-```bash
-$ git clone [email protected]:rust-analyzer/rust-analyzer && cd rust-analyzer
-$ cargo xtask install --server # or cargo install --path ./crates/ra_lsp_server
-```
-
-This way you will get a binary named `ra_lsp_server` (with os suffix for prebuilt binaries)
-which you should be able to use with any LSP-compatible editor.
-
-We make use of custom extensions to LSP, so special client-side support is required to take full
-advantage of rust-analyzer. This repository contains support code for VS Code.
-
-Rust Analyzer needs sources of rust standard library to work, so
-you might also need to execute
-
-```
-$ rustup component add rust-src
-```
-
-See [./features.md](./features.md) document for a list of features that are available.
-
-## VS Code
-
-### Prerequisites
-
-You will need the most recent version of VS Code: we don't try to
-maintain compatibility with older versions yet.
-
-### Installation from prebuilt binaries
-
-We ship prebuilt binaries for Linux, Mac and Windows via
-[GitHub releases][github-releases].
-In order to use them you need to install the client VSCode extension.
-
-Publishing to VS Code marketplace is currently WIP. Thus, you need to manually download
-`rust-analyzer-0.1.0.vsix` file from latest [GitHub release][github-releases].
-
-After you downloaded the `.vsix` file you can install it from the terminal
-
-```
-$ code --install-extension rust-analyzer-0.1.0.vsix
-```
-
-Or open VS Code, press <kbd>Ctrl+Shift+P</kbd>, and search for the following command:
-
-<img width="500px" alt="Install from VSIX command" src="https://user-images.githubusercontent.com/36276403/74108225-c0c11d80-4b80-11ea-9b2a-0a43f09e29af.png">
-
-Press <kbd>Enter</kbd> and go to `rust-analyzer-0.1.0.vsix` file through the file explorer.
-
-Then open some Rust project and you should
-see an info message pop-up.
-
-<img height="140px" src="https://user-images.githubusercontent.com/36276403/74103174-a40df100-4b52-11ea-81f4-372c70797924.png" alt="Download now message"/>
-
-
-Click `Download now`, wait until the progress is 100% and you are ready to go.
-
-For updates you need to remove installed binary
-```
-rm -rf ${HOME}/.config/Code/User/globalStorage/matklad.rust-analyzer
-```
-
-`"Download latest language server"` command for VSCode and automatic updates detection is currently WIP.
-
-
-### Installation from sources
-
-In order to build the VS Code plugin from sources, you need to have node.js and npm with
-a minimum version of 12 installed. Please refer to
-[node.js and npm documentation](https://nodejs.org) for installation instructions.
-
-The experimental VS Code plugin can be built and installed by executing the
-following commands:
-
-```
-$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
-$ cd rust-analyzer
-$ cargo xtask install
-```
-
-After that you need to amend your `settings.json` file to explicitly specify the
-path to `ra_lsp_server` that you've just built.
-```json
-{
-    "rust-analyzer.raLspServerPath": "ra_lsp_server"
-}
-```
-This should work on all platforms, otherwise if installed `ra_lsp_server` is not available through your `$PATH` then see how to configure it [here](#setting-up-the-PATH-variable).
-
-
-The automatic installation is expected to *just work* for common cases, if it
-doesn't, report bugs!
-
-**Note** [#1831](https://github.com/rust-analyzer/rust-analyzer/issues/1831): If you are using the popular
-[Vim emulation plugin](https://github.com/VSCodeVim/Vim), you will likely
-need to turn off the `rust-analyzer.enableEnhancedTyping` setting.
-(// TODO: This configuration is no longer available, enhanced typing shoud be disabled via removing Enter key binding, [see this issue](https://github.com/rust-analyzer/rust-analyzer/issues/3051))
-
-If you have an unusual setup (for example, `code` is not in the `PATH`), you
-should adapt these manual installation instructions:
-
-```
-$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
-$ cd rust-analyzer
-$ cargo install --path ./crates/ra_lsp_server/ --force --locked
-$ cd ./editors/code
-$ npm install
-$ npm run package
-$ code --install-extension ./rust-analyzer-0.1.0.vsix
-```
-
-It's better to remove existing Rust plugins to avoid interference.
-
-Beyond basic LSP features, there are some extension commands which you can
-invoke via <kbd>Ctrl+Shift+P</kbd> or bind to a shortcut. See [./features.md](./features.md)
-for details.
-
-For updates, pull the latest changes from the master branch, run `cargo xtask install` again, and **restart** VS Code instance.
-See [microsoft/vscode#72308](https://github.com/microsoft/vscode/issues/72308) for why a full restart is needed.
-
-### VS Code Remote
-
-You can also use `rust-analyzer` with the Visual Studio Code Remote extensions
-(Remote SSH, Remote WSL, Remote Containers). In this case, however, you have to
-manually install the `.vsix` package:
-
-1. Build the extension on the remote host using the instructions above (ignore the
-   error if `code` cannot be found in your PATH: VSCode doesn't need to be installed
-   on the remote host).
-2. In Visual Studio Code open a connection to the remote host.
-3. Open the Extensions View (`View > Extensions`, keyboard shortcut: `Ctrl+Shift+X`).
-4. From the top-right kebab menu (`···`) select `Install from VSIX...`
-5. Inside the `rust-analyzer` directory find the `editors/code` subdirectory and choose
-   the `rust-analyzer-0.1.0.vsix` file.
-6. Restart Visual Studio Code and re-establish the connection to the remote host.
-
-In case of errors please make sure that `~/.cargo/bin` is in your `PATH` on the remote
-host.
-
-### Settings
-
-* `rust-analyzer.highlightingOn`: enables experimental syntax highlighting.
-  Colors can be configured via `editor.tokenColorCustomizations`.
-  As an example, [Pale Fire](https://github.com/matklad/pale-fire/) color scheme tweaks rust colors.
-* `rust-analyzer.enableEnhancedTyping`: by default, rust-analyzer intercepts the
-  `Enter` key to make it easier to continue comments. Note that it may conflict with VIM emulation plugin.
-* `rust-analyzer.raLspServerPath`: path to `ra_lsp_server` executable, when absent or `null` defaults to prebuilt binary path
-* `rust-analyzer.enableCargoWatchOnStartup`: prompt to install & enable `cargo
-  watch` for live error highlighting (note, this **does not** use rust-analyzer)
-* `rust-analyzer.excludeGlobs`: a list of glob-patterns for exclusion (see globset [docs](https://docs.rs/globset) for syntax).
-  Note: glob patterns are applied to all Cargo packages and a rooted at a package root.
-  This is not very intuitive and a limitation of a current implementation.
-* `rust-analyzer.useClientWatching`: use client provided file watching instead
-  of notify watching.
-* `rust-analyzer.cargo-watch.command`: `cargo-watch` command. (e.g: `clippy` will run as `cargo watch -x clippy` )
-* `rust-analyzer.cargo-watch.arguments`: cargo-watch check arguments.
-  (e.g: `--features="shumway,pdf"` will run as `cargo watch -x "check --features="shumway,pdf""` )
-* `rust-analyzer.cargo-watch.ignore`: list of patterns for cargo-watch to ignore (will be passed as `--ignore`)
-* `rust-analyzer.trace.server`: enables internal logging
-* `rust-analyzer.trace.cargo-watch`: enables cargo-watch logging
-* `RUST_SRC_PATH`: environment variable that overwrites the sysroot
-* `rust-analyzer.featureFlags` -- a JSON object to tweak fine-grained behavior:
-   ```jsonc
-   {
-       // Show diagnostics produced by rust-analyzer itself.
-       "lsp.diagnostics": true,
-       // Automatically insert `()` and `<>` when completing functions and types.
-       "completion.insertion.add-call-parenthesis": true,
-       // Enable completions like `.if`, `.match`, etc.
-       "completion.enable-postfix": true,
-       // Show notification when workspace is fully loaded
-       "notifications.workspace-loaded": true,
-       // Show error when no Cargo.toml was found
-       "notifications.cargo-toml-not-found": true,
-   }
-   ```
-
-
-## Emacs
-
-* install recent version of `emacs-lsp` package by following the instructions [here][emacs-lsp]
-* set `lsp-rust-server` to `'rust-analyzer`
-* run `lsp` in a Rust buffer
-* (Optionally) bind commands like `lsp-rust-analyzer-join-lines`, `lsp-extend-selection` and `lsp-rust-analyzer-expand-macro` to keys
-
-[emacs-lsp]: https://github.com/emacs-lsp/lsp-mode
-
-
-## Vim and NeoVim (coc-rust-analyzer)
-
-* Install coc.nvim by following the instructions at [coc.nvim][] (nodejs required)
-* Run `:CocInstall coc-rust-analyzer` to install [coc-rust-analyzer], this extension implements _most_ of the features supported in the VSCode extension:
-  - same configurations as VSCode extension, `rust-analyzer.raLspServerPath`, `rust-analyzer.enableCargoWatchOnStartup` etc.
-  - same commands too, `rust-analyzer.analyzerStatus`, `rust-analyzer.startCargoWatch` etc.
-  - highlighting and inlay_hints are not implemented yet
-
-[coc.nvim]: https://github.com/neoclide/coc.nvim
-[coc-rust-analyzer]: https://github.com/fannheyward/coc-rust-analyzer
-
-## Vim and NeoVim (LanguageClient-neovim)
-
-* Install LanguageClient-neovim by following the instructions [here][lang-client-neovim]
-  - The github project wiki has extra tips on configuration
-
-* Configure by adding this to your vim/neovim config file (replacing the existing rust specific line if it exists):
-
-```vim
-let g:LanguageClient_serverCommands = {
-\ 'rust': ['ra_lsp_server'],
-\ }
-```
-
-[lang-client-neovim]: https://github.com/autozimu/LanguageClient-neovim
-
-## NeoVim (nvim-lsp)
-
-NeoVim 0.5 (not yet released) has built in language server support. For a quick start configuration
-of rust-analyzer, use [neovim/nvim-lsp](https://github.com/neovim/nvim-lsp#rust_analyzer).
-Once `neovim/nvim-lsp` is installed, use `lua require'nvim_lsp'.rust_analyzer.setup({})` in your `init.vim`.
-
-
-## Sublime Text 3
-
-Prequisites:
-
-`LSP` package.
-
-Installation:
-
-* Invoke the command palette with <kbd>Ctrl+Shift+P</kbd>
-* Type `LSP Settings` to open the LSP preferences editor
-* Add the following LSP client definition to your settings:
-
-```json
-"rust-analyzer": {
-    "command": ["ra_lsp_server"],
-    "languageId": "rust",
-    "scopes": ["source.rust"],
-    "syntaxes": [
-        "Packages/Rust/Rust.sublime-syntax",
-        "Packages/Rust Enhanced/RustEnhanced.sublime-syntax"
-    ],
-    "initializationOptions": {
-      "featureFlags": {
-      }
-    },
-}
-```
-
-* You can now invoke the command palette and type LSP enable to locally/globally enable the rust-analyzer LSP (type LSP enable, then choose either locally or globally, then select rust-analyzer)
-
-
-<!-- Update links to this header when changing it! -->
-### Setting up the `PATH` variable
-
-On Unix systems, `rustup` adds `~/.cargo/bin` to `PATH` by modifying the shell's
-startup file. Depending on your configuration, your Desktop Environment might not
-actually load it. If you find that `rust-analyzer` only runs when starting the
-editor from the terminal, you will have to set up your `PATH` variable manually.
-
-There are a couple of ways to do that:
-
-- for Code, set `rust-analyzer.raLspServerPath` to `~/.cargo/bin` (the `~` is
-  automatically resolved by the extension)
-- copy the binary to a location that is already in `PATH`, e.g. `/usr/local/bin`
-- on Linux, use PAM to configure the `PATH` variable, by e.g. putting
-  `PATH DEFAULT=/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:@{HOME}/.cargo/bin:@{HOME}/.local/bin`
-  in your `~/.pam_environment` file; note that this might interfere with other
-  defaults set by the system administrator via `/etc/environment`.
diff --git a/docs/user/readme.adoc b/docs/user/readme.adoc
new file mode 100644
index 000000000..867aae975
--- /dev/null
+++ b/docs/user/readme.adoc
@@ -0,0 +1,155 @@
+= User Manual
+:toc: preamble
+:sectanchors:
+:page-layout: post
+
+
+// Master copy of this document lives in the https://github.com/rust-analyzer/rust-analyzer repository
+
+At it's core, rust-analyzer is a *library* for semantic analysis of the Rust code as it changes over time.
+This manual focuses on a specific usage of the library -- the implementation of
+https://microsoft.github.io/language-server-protocol/[Language Server Protocol].
+LSP allows various code editors, like VS Code, Emacs or Vim, to implement semantic feature like completion or goto definition by talking to an external language server process.
+
+To improve this document, send a pull request against
+https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/readme.adoc[this file].
+
+== Installation
+
+In theory, one should be able to just install the server binary and have it automatically work with any editor.
+We are not there yet, so some editor specific setup is required.
+
+=== VS Code
+
+This the best supported editor at the moment.
+rust-analyzer plugin for VS Code is maintained
+https://github.com/rust-analyzer/rust-analyzer/tree/master/editors/code[in tree].
+
+You can install the latest release of the plugin from
+https://marketplace.visualstudio.com/items?itemName=matklad.rust-analyzer[the marketplace].
+By default, the plugin will download the latest version of the server as well.
+
+image::https://user-images.githubusercontent.com/36276403/74103174-a40df100-4b52-11ea-81f4-372c70797924.png[]
+
+The server binary is stored in `~/.config/Code/User/globalStorage/matklad.rust-analyzer`.
+
+Note that we only support the latest version of VS Code.
+
+==== Updates
+
+The extension will be updated automatically as new versions become available.
+The server update functionality is in progress.
+For the time being, the workaround is to remove the binary from `globalStorage` and to restart the extension.
+
+==== Building From Source
+
+Alternatively, both the server and the plugin can be installed from source:
+
+[source]
+----
+$ git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
+$ cargo xtask install
+----
+
+You'll need Cargo, nodejs and npm for this.
+To make VS Code use the freshly build server, add this to the settings:
+
+[source,json]
+----
+{ "rust-analyzer.raLspServerPath": "ra_lsp_server" }
+----
+
+Note that installing via `xtask install` does not work for VS Code Remote, instead you'll need to install the `.vsix` manually.
+
+=== Language Server Binary
+
+Other editors generally require `ra_lsp_server` binary to be in `$PATH`.
+You can download pre-build binary from
+https://github.com/rust-analyzer/rust-analyzer/releases[relases]
+page, or you can install it from source using the following command:
+
+[source,bash]
+----
+$ cargo xtask install --server
+----
+
+=== Emacs
+
+Emacs support is maintained https://github.com/emacs-lsp/lsp-mode/blob/master/lsp-rust.el[upstream].
+
+1. Install recent version of `emacs-lsp` package by following the instructions https://github.com/emacs-lsp/lsp-mode[here].
+2. Set `lsp-rust-server` to `'rust-analyzer`.
+3. Run `lsp` in a Rust buffer.
+4. (Optionally) bind commands like `lsp-rust-analyzer-join-lines`, `lsp-extend-selection` and `lsp-rust-analyzer-expand-macro` to keys.
+
+=== Vim
+
+The are several LSP client implementations for vim:
+
+==== coc-rust-analyzer
+
+1. Install coc.nvim by following the instructions at
+   https://github.com/neoclide/coc.nvim[coc.nvim]
+   (nodejs required)
+2. Run `:CocInstall coc-rust-analyzer` to install
+   https://github.com/fannheyward/coc-rust-analyzer[coc-rust-analyzer],
+   this extension implements _most_ of the features supported in the VSCode extension:
+   * same configurations as VSCode extension, `rust-analyzer.raLspServerPath`, `rust-analyzer.enableCargoWatchOnStartup` etc.
+   * same commands too, `rust-analyzer.analyzerStatus`, `rust-analyzer.startCargoWatch` etc.
+   * highlighting and inlay_hints are not implemented yet
+
+==== LanguageClient-neovim
+
+1. Install LanguageClient-neovim by following the instructions
+   https://github.com/autozimu/LanguageClient-neovim[here]
+   * The github project wiki has extra tips on configuration
+
+2. Configure by adding this to your vim/neovim config file (replacing the existing rust specific line if it exists):
++
+[source,vim]
+----
+let g:LanguageClient_serverCommands = {
+\ 'rust': ['ra_lsp_server'],
+\ }
+----
+
+==== nvim-lsp
+
+NeoVim 0.5 (not yet released) has built in language server support.
+For a quick start configuration of rust-analyzer, use https://github.com/neovim/nvim-lsp#rust_analyzer[neovim/nvim-lsp].
+Once `neovim/nvim-lsp` is installed, use `lua require'nvim_lsp'.rust_analyzer.setup({})` in your `init.vim`.
+
+=== Sublime Text 3
+
+Prerequisites:
+
+`LSP` package.
+
+Installation:
+
+1. Invoke the command palette with <kbd>Ctrl+Shift+P</kbd>
+2. Type `LSP Settings` to open the LSP preferences editor
+3. Add the following LSP client definition to your settings:
++
+[source,json]
+----
+"rust-analyzer": {
+    "command": ["ra_lsp_server"],
+    "languageId": "rust",
+    "scopes": ["source.rust"],
+    "syntaxes": [
+        "Packages/Rust/Rust.sublime-syntax",
+        "Packages/Rust Enhanced/RustEnhanced.sublime-syntax"
+    ],
+    "initializationOptions": {
+      "featureFlags": {
+      }
+    },
+}
+----
+
+4. You can now invoke the command palette and type LSP enable to locally/globally enable the rust-analyzer LSP (type LSP enable, then choose either locally or globally, then select rust-analyzer)
+
+== Usage
+
+See https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/features.md[features.md].
diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index 5c056463e..c74078735 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -1,6 +1,6 @@
 {
     "name": "rust-analyzer",
-    "version": "0.1.0",
+    "version": "0.2.0-dev",
     "lockfileVersion": 1,
     "requires": true,
     "dependencies": {
@@ -107,9 +107,9 @@
             "dev": true
         },
         "@types/vscode": {
-            "version": "1.41.0",
-            "resolved": "https://registry.npmjs.org/@types/vscode/-/vscode-1.41.0.tgz",
-            "integrity": "sha512-7SfeY5u9jgiELwxyLB3z7l6l/GbN9CqpCQGkcRlB7tKRFBxzbz2PoBfGrLxI1vRfUCIq5+hg5vtDHExwq5j3+A==",
+            "version": "1.42.0",
+            "resolved": "https://registry.npmjs.org/@types/vscode/-/vscode-1.42.0.tgz",
+            "integrity": "sha512-ds6TceMsh77Fs0Mq0Vap6Y72JbGWB8Bay4DrnJlf5d9ui2RSe1wis13oQm+XhguOeH1HUfLGzaDAoupTUtgabw==",
             "dev": true
         },
         "acorn": {
@@ -662,9 +662,9 @@
             }
         },
         "readable-stream": {
-            "version": "3.4.0",
-            "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.4.0.tgz",
-            "integrity": "sha512-jItXPLmrSR8jmTRmRWJXCnGJsfy85mB3Wd/uINMXA65yrnFo0cPClFIUWzo2najVNSl+mx7/4W8ttlLWJe99pQ==",
+            "version": "3.6.0",
+            "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-3.6.0.tgz",
+            "integrity": "sha512-BViHy7LKeTz4oNnkcLJ+lVSL6vpiFeX6/d3oSH8zCW7UxP2onchk+vTGB143xuFjHS3deTgkKoXXymXqymiIdA==",
             "dev": true,
             "requires": {
                 "inherits": "^2.0.3",
@@ -860,9 +860,9 @@
             "dev": true
         },
         "vsce": {
-            "version": "1.71.0",
-            "resolved": "https://registry.npmjs.org/vsce/-/vsce-1.71.0.tgz",
-            "integrity": "sha512-7k+LPC4oJYPyyxs0a5nh4A8CleQ6+2EMPiAiX/bDyN+PmwJFm2FFPqLRxdIsIWfFnkW4ZMQBf10+W62dCRd9kQ==",
+            "version": "1.73.0",
+            "resolved": "https://registry.npmjs.org/vsce/-/vsce-1.73.0.tgz",
+            "integrity": "sha512-6W37Ebbkj3uF3WhT+SCfRtsneRQEFcGvf/XYz+b6OAgDCj4gPurWyDVrqw/HLsbP1WflGIyUfVZ8t5M7kQp6Uw==",
             "dev": true,
             "requires": {
                 "azure-devops-node-api": "^7.2.0",
diff --git a/editors/code/package.json b/editors/code/package.json
index 12d32cef7..a607c2148 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -5,7 +5,8 @@
     "preview": true,
     "private": true,
     "icon": "icon.png",
-    "version": "0.1.0",
+    "//": "The real version is in release.yaml, this one just needs to be bigger",
+    "version": "0.2.0-dev",
     "publisher": "matklad",
     "repository": {
         "url": "https://github.com/rust-analyzer/rust-analyzer.git",
@@ -15,7 +16,7 @@
         "Other"
     ],
     "engines": {
-        "vscode": "^1.41.0"
+        "vscode": "^1.42.0"
     },
     "scripts": {
         "vscode:prepublish": "tsc && rollup -c",
@@ -35,13 +36,13 @@
         "@types/node": "^12.12.25",
         "@types/node-fetch": "^2.5.4",
         "@types/throttle-debounce": "^2.1.0",
-        "@types/vscode": "^1.41.0",
+        "@types/vscode": "^1.42.0",
         "rollup": "^1.31.0",
         "tslib": "^1.10.0",
         "tslint": "^5.20.1",
         "typescript": "^3.7.5",
         "typescript-formatter": "^7.2.2",
-        "vsce": "^1.71.0"
+        "vsce": "^1.73.0"
     },
     "activationEvents": [
         "onLanguage:rust",
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 4484b2167..dcf9d0c06 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -3,6 +3,7 @@ import * as vscode from 'vscode';
 
 import { Config } from './config';
 import { ensureLanguageServerBinary } from './installation/language_server';
+import { CallHierarchyFeature } from 'vscode-languageclient/lib/callHierarchy.proposed';
 
 export async function createClient(config: Config): Promise<null | lc.LanguageClient> {
     // '.' Is the fallback if no folder is open
@@ -80,6 +81,10 @@ export async function createClient(config: Config): Promise<null | lc.LanguageCl
             }
         },
     };
-    res.registerProposedFeatures();
+
+    // To turn on all proposed features use: res.registerProposedFeatures();
+    // Here we want to just enable CallHierarchyFeature since it is available on stable.
+    // Note that while the CallHierarchyFeature is stable the LSP protocol is not.
+    res.registerFeature(new CallHierarchyFeature(res));
     return res;
 }
diff --git a/editors/code/src/installation/download_file.ts b/editors/code/src/installation/download_file.ts
index f1f9f4a25..d154f4816 100644
--- a/editors/code/src/installation/download_file.ts
+++ b/editors/code/src/installation/download_file.ts
@@ -1,7 +1,11 @@
 import fetch from "node-fetch";
 import * as fs from "fs";
+import * as stream from "stream";
+import * as util from "util";
 import { strict as assert } from "assert";
 
+const pipeline = util.promisify(stream.pipeline);
+
 /**
  * Downloads file from `url` and stores it at `destFilePath` with `destFilePermissions`.
  * `onProgress` callback is called on recieveing each chunk of bytes
@@ -20,25 +24,28 @@ export async function downloadFile(
         console.log("Error", res.status, "while downloading file from", url);
         console.dir({ body: await res.text(), headers: res.headers }, { depth: 3 });
 
-        throw new Error(`Got response ${res.status} when trying to download a file`);
+        throw new Error(`Got response ${res.status} when trying to download a file.`);
     }
 
     const totalBytes = Number(res.headers.get('content-length'));
     assert(!Number.isNaN(totalBytes), "Sanity check of content-length protocol");
 
+    console.log("Downloading file of", totalBytes, "bytes size from", url, "to", destFilePath);
+
     let readBytes = 0;
+    res.body.on("data", (chunk: Buffer) => {
+        readBytes += chunk.length;
+        onProgress(readBytes, totalBytes);
+    });
 
-    console.log("Downloading file of", totalBytes, "bytes size from", url, "to", destFilePath);
+    const destFileStream = fs.createWriteStream(destFilePath, { mode: destFilePermissions });
+
+    await pipeline(res.body, destFileStream);
+    return new Promise<void>(resolve => {
+        destFileStream.on("close", resolve);
+        destFileStream.destroy();
 
-    return new Promise<void>((resolve, reject) => res.body
-        .on("data", (chunk: Buffer) => {
-            readBytes += chunk.length;
-            onProgress(readBytes, totalBytes);
-        })
-        .on("error", reject)
-        .pipe(fs
-            .createWriteStream(destFilePath, { mode: destFilePermissions })
-            .on("close", resolve)
-        )
-    );
+        // Details on workaround: https://github.com/rust-analyzer/rust-analyzer/pull/3092#discussion_r378191131
+        // Issue at nodejs repo: https://github.com/nodejs/node/issues/31776
+    });
 }
diff --git a/editors/code/src/installation/language_server.ts b/editors/code/src/installation/language_server.ts
index 52c5cbe7d..4797c3f01 100644
--- a/editors/code/src/installation/language_server.ts
+++ b/editors/code/src/installation/language_server.ts
@@ -104,6 +104,8 @@ export async function ensureLanguageServerBinary(
                     `GitHub repository: ${err.message}`
                 );
 
+                console.error(err);
+
                 dns.resolve('example.com').then(
                     addrs => console.log("DNS resolution for example.com was successful", addrs),
                     err => {
diff --git a/xtask/src/cmd.rs b/xtask/src/cmd.rs
deleted file mode 100644
index 37497fb74..000000000
--- a/xtask/src/cmd.rs
+++ /dev/null
@@ -1,56 +0,0 @@
-use std::process::{Command, Output, Stdio};
-
-use anyhow::{Context, Result};
-
-use crate::project_root;
-
-pub struct Cmd<'a> {
-    pub unix: &'a str,
-    pub windows: &'a str,
-    pub work_dir: &'a str,
-}
-
-impl Cmd<'_> {
-    pub fn run(self) -> Result<()> {
-        if cfg!(windows) {
-            run(self.windows, self.work_dir)
-        } else {
-            run(self.unix, self.work_dir)
-        }
-    }
-    pub fn run_with_output(self) -> Result<String> {
-        if cfg!(windows) {
-            run_with_output(self.windows, self.work_dir)
-        } else {
-            run_with_output(self.unix, self.work_dir)
-        }
-    }
-}
-
-pub fn run(cmdline: &str, dir: &str) -> Result<()> {
-    do_run(cmdline, dir, &mut |c| {
-        c.stdout(Stdio::inherit());
-    })
-    .map(|_| ())
-}
-
-pub fn run_with_output(cmdline: &str, dir: &str) -> Result<String> {
-    let output = do_run(cmdline, dir, &mut |_| {})?;
-    let stdout = String::from_utf8(output.stdout)?;
-    let stdout = stdout.trim().to_string();
-    Ok(stdout)
-}
-
-fn do_run(cmdline: &str, dir: &str, f: &mut dyn FnMut(&mut Command)) -> Result<Output> {
-    eprintln!("\nwill run: {}", cmdline);
-    let proj_dir = project_root().join(dir);
-    let mut args = cmdline.split_whitespace();
-    let exec = args.next().unwrap();
-    let mut cmd = Command::new(exec);
-    f(cmd.args(args).current_dir(proj_dir).stderr(Stdio::inherit()));
-    let output = cmd.output().with_context(|| format!("running `{}`", cmdline))?;
-    if !output.status.success() {
-        anyhow::bail!("`{}` exited with {}", cmdline, output.status);
-    }
-    Ok(output)
-}
diff --git a/xtask/src/install.rs b/xtask/src/install.rs
index 99e1eddb1..540a66130 100644
--- a/xtask/src/install.rs
+++ b/xtask/src/install.rs
@@ -2,9 +2,9 @@
 
 use std::{env, path::PathBuf, str};
 
-use anyhow::{Context, Result};
+use anyhow::{bail, format_err, Context, Result};
 
-use crate::cmd::{run, run_with_output, Cmd};
+use crate::not_bash::{ls, pushd, rm, run};
 
 // Latest stable, feel free to send a PR if this lags behind.
 const REQUIRED_RUST_VERSION: u32 = 41;
@@ -55,7 +55,7 @@ fn fix_path_for_mac() -> Result<()> {
         const ROOT_DIR: &str = "";
         let home_dir = match env::var("HOME") {
             Ok(home) => home,
-            Err(e) => anyhow::bail!("Failed getting HOME from environment with error: {}.", e),
+            Err(e) => bail!("Failed getting HOME from environment with error: {}.", e),
         };
 
         [ROOT_DIR, &home_dir]
@@ -69,7 +69,7 @@ fn fix_path_for_mac() -> Result<()> {
     if !vscode_path.is_empty() {
         let vars = match env::var_os("PATH") {
             Some(path) => path,
-            None => anyhow::bail!("Could not get PATH variable from env."),
+            None => bail!("Could not get PATH variable from env."),
         };
 
         let mut paths = env::split_paths(&vars).collect::<Vec<_>>();
@@ -82,84 +82,61 @@ fn fix_path_for_mac() -> Result<()> {
 }
 
 fn install_client(ClientOpt::VsCode: ClientOpt) -> Result<()> {
-    let npm_version = Cmd {
-        unix: r"npm --version",
-        windows: r"cmd.exe /c npm --version",
-        work_dir: "./editors/code",
-    }
-    .run();
-
-    if npm_version.is_err() {
-        eprintln!("\nERROR: `npm --version` failed, `npm` is required to build the VS Code plugin")
-    }
+    let _dir = pushd("./editors/code");
 
-    Cmd { unix: r"npm install", windows: r"cmd.exe /c npm install", work_dir: "./editors/code" }
-        .run()?;
-    Cmd {
-        unix: r"npm run package --scripts-prepend-node-path",
-        windows: r"cmd.exe /c npm run package",
-        work_dir: "./editors/code",
-    }
-    .run()?;
+    let find_code = |f: fn(&str) -> bool| -> Result<&'static str> {
+        ["code", "code-insiders", "codium", "code-oss"]
+            .iter()
+            .copied()
+            .find(|bin| f(bin))
+            .ok_or_else(|| {
+                format_err!("Can't execute `code --version`. Perhaps it is not in $PATH?")
+            })
+    };
 
-    let code_binary = ["code", "code-insiders", "codium", "code-oss"].iter().find(|bin| {
-        Cmd {
-            unix: &format!("{} --version", bin),
-            windows: &format!("cmd.exe /c {}.cmd --version", bin),
-            work_dir: "./editors/code",
-        }
-        .run()
-        .is_ok()
-    });
+    let installed_extensions;
+    if cfg!(unix) {
+        run!("npm --version").context("`npm` is required to build the VS Code plugin")?;
+        run!("npm install")?;
 
-    let code_binary = match code_binary {
-        Some(it) => it,
-        None => anyhow::bail!("Can't execute `code --version`. Perhaps it is not in $PATH?"),
-    };
+        let vsix_pkg = {
+            rm("*.vsix")?;
+            run!("npm run package --scripts-prepend-node-path")?;
+            ls("*.vsix")?.pop().unwrap()
+        };
 
-    Cmd {
-        unix: &format!(r"{} --install-extension ./rust-analyzer-0.1.0.vsix --force", code_binary),
-        windows: &format!(
-            r"cmd.exe /c {}.cmd --install-extension ./rust-analyzer-0.1.0.vsix --force",
-            code_binary
-        ),
-        work_dir: "./editors/code",
-    }
-    .run()?;
+        let code = find_code(|bin| run!("{} --version", bin).is_ok())?;
+        run!("{} --install-extension {} --force", code, vsix_pkg.display())?;
+        installed_extensions = run!("{} --list-extensions", code; echo = false)?;
+    } else {
+        run!("cmd.exe /c npm --version")
+            .context("`npm` is required to build the VS Code plugin")?;
+        run!("cmd.exe /c npm install")?;
+
+        let vsix_pkg = {
+            rm("*.vsix")?;
+            run!("cmd.exe /c npm run package")?;
+            ls("*.vsix")?.pop().unwrap()
+        };
 
-    let installed_extensions = Cmd {
-        unix: &format!(r"{} --list-extensions", code_binary),
-        windows: &format!(r"cmd.exe /c {}.cmd --list-extensions", code_binary),
-        work_dir: ".",
+        let code = find_code(|bin| run!("cmd.exe /c {}.cmd --version", bin).is_ok())?;
+        run!(r"cmd.exe /c {}.cmd --install-extension {} --force", code, vsix_pkg.display())?;
+        installed_extensions = run!("cmd.exe /c {}.cmd --list-extensions", code; echo = false)?;
     }
-    .run_with_output()?;
 
     if !installed_extensions.contains("rust-analyzer") {
-        anyhow::bail!(
+        bail!(
             "Could not install the Visual Studio Code extension. \
              Please make sure you have at least NodeJS 10.x together with the latest version of VS Code installed and try again."
         );
     }
 
-    if installed_extensions.contains("ra-lsp") {
-        Cmd {
-            unix: &format!(r"{} --uninstall-extension matklad.ra-lsp", code_binary),
-            windows: &format!(
-                r"cmd.exe /c {}.cmd --uninstall-extension matklad.ra-lsp",
-                code_binary
-            ),
-            work_dir: "./editors/code",
-        }
-        .run()?;
-    }
-
     Ok(())
 }
 
 fn install_server(opts: ServerOpt) -> Result<()> {
     let mut old_rust = false;
-    if let Ok(stdout) = run_with_output("cargo --version", ".") {
-        println!("{}", stdout);
+    if let Ok(stdout) = run!("cargo --version") {
         if !check_version(&stdout, REQUIRED_RUST_VERSION) {
             old_rust = true;
         }
@@ -172,20 +149,17 @@ fn install_server(opts: ServerOpt) -> Result<()> {
         )
     }
 
-    let res = if opts.jemalloc {
-        run("cargo install --path crates/ra_lsp_server --locked --force --features jemalloc", ".")
-    } else {
-        run("cargo install --path crates/ra_lsp_server --locked --force", ".")
-    };
+    let jemalloc = if opts.jemalloc { "--features jemalloc" } else { "" };
+    let res = run!("cargo install --path crates/ra_lsp_server --locked --force {}", jemalloc);
 
     if res.is_err() && old_rust {
         eprintln!(
             "\nWARNING: at least rust 1.{}.0 is required to compile rust-analyzer\n",
             REQUIRED_RUST_VERSION,
-        )
+        );
     }
 
-    res
+    res.map(drop)
 }
 
 fn check_version(version_output: &str, min_minor_version: u32) -> bool {
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index 1bb1882b0..2bcd76d60 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-mod cmd;
+pub mod not_bash;
 pub mod install;
 pub mod pre_commit;
 
@@ -9,15 +9,15 @@ mod ast_src;
 
 use anyhow::Context;
 use std::{
-    env, fs,
+    env,
     io::Write,
     path::{Path, PathBuf},
     process::{Command, Stdio},
 };
 
 use crate::{
-    cmd::{run, run_with_output},
     codegen::Mode,
+    not_bash::{fs2, pushd, rm_rf, run},
 };
 
 pub use anyhow::Result;
@@ -38,9 +38,9 @@ pub fn run_rustfmt(mode: Mode) -> Result<()> {
     ensure_rustfmt()?;
 
     if mode == Mode::Verify {
-        run(&format!("rustup run {} -- cargo fmt -- --check", TOOLCHAIN), ".")?;
+        run!("rustup run {} -- cargo fmt -- --check", TOOLCHAIN)?;
     } else {
-        run(&format!("rustup run {} -- cargo fmt", TOOLCHAIN), ".")?;
+        run!("rustup run {} -- cargo fmt", TOOLCHAIN)?;
     }
     Ok(())
 }
@@ -70,8 +70,9 @@ fn ensure_rustfmt() -> Result<()> {
         Ok(status) if status.success() => return Ok(()),
         _ => (),
     };
-    run(&format!("rustup toolchain install {}", TOOLCHAIN), ".")?;
-    run(&format!("rustup component add rustfmt --toolchain {}", TOOLCHAIN), ".")
+    run!("rustup toolchain install {}", TOOLCHAIN)?;
+    run!("rustup component add rustfmt --toolchain {}", TOOLCHAIN)?;
+    Ok(())
 }
 
 pub fn run_clippy() -> Result<()> {
@@ -92,34 +93,28 @@ pub fn run_clippy() -> Result<()> {
         "clippy::nonminimal_bool",
         "clippy::redundant_pattern_matching",
     ];
-    run(
-        &format!(
-            "rustup run {} -- cargo clippy --all-features --all-targets -- -A {}",
-            TOOLCHAIN,
-            allowed_lints.join(" -A ")
-        ),
-        ".",
+    run!(
+        "rustup run {} -- cargo clippy --all-features --all-targets -- -A {}",
+        TOOLCHAIN,
+        allowed_lints.join(" -A ")
     )?;
     Ok(())
 }
 
 fn install_clippy() -> Result<()> {
-    run(&format!("rustup toolchain install {}", TOOLCHAIN), ".")?;
-    run(&format!("rustup component add clippy --toolchain {}", TOOLCHAIN), ".")
+    run!("rustup toolchain install {}", TOOLCHAIN)?;
+    run!("rustup component add clippy --toolchain {}", TOOLCHAIN)?;
+    Ok(())
 }
 
 pub fn run_fuzzer() -> Result<()> {
-    match Command::new("cargo")
-        .args(&["fuzz", "--help"])
-        .stderr(Stdio::null())
-        .stdout(Stdio::null())
-        .status()
-    {
-        Ok(status) if status.success() => (),
-        _ => run("cargo install cargo-fuzz", ".")?,
+    let _d = pushd("./crates/ra_syntax");
+    if run!("cargo fuzz --help").is_err() {
+        run!("cargo install cargo-fuzz")?;
     };
 
-    run("rustup run nightly -- cargo fuzz run parser", "./crates/ra_syntax")
+    run!("rustup run nightly -- cargo fuzz run parser")?;
+    Ok(())
 }
 
 /// Cleans the `./target` dir after the build such that only
@@ -141,7 +136,7 @@ pub fn run_pre_cache() -> Result<()> {
         }
     }
 
-    fs::remove_file("./target/.rustc_info.json")?;
+    fs2::remove_file("./target/.rustc_info.json")?;
     let to_delete = ["ra_", "heavy_test"];
     for &dir in ["./target/debug/deps", "target/debug/.fingerprint"].iter() {
         for entry in Path::new(dir).read_dir()? {
@@ -155,22 +150,20 @@ pub fn run_pre_cache() -> Result<()> {
     Ok(())
 }
 
-fn rm_rf(path: &Path) -> Result<()> {
-    if path.is_file() { fs::remove_file(path) } else { fs::remove_dir_all(path) }
-        .with_context(|| format!("failed to remove {:?}", path))
-}
-
-pub fn run_release() -> Result<()> {
-    run("git switch release", ".")?;
-    run("git fetch upstream", ".")?;
-    run("git reset --hard upstream/master", ".")?;
-    run("git push", ".")?;
+pub fn run_release(dry_run: bool) -> Result<()> {
+    if !dry_run {
+        run!("git switch release")?;
+        run!("git fetch upstream")?;
+        run!("git reset --hard upstream/master")?;
+        run!("git push")?;
+    }
 
-    let changelog_dir = project_root().join("../rust-analyzer.github.io/thisweek/_posts");
+    let website_root = project_root().join("../rust-analyzer.github.io");
+    let changelog_dir = website_root.join("./thisweek/_posts");
 
-    let today = run_with_output("date --iso", ".")?;
-    let commit = run_with_output("git rev-parse HEAD", ".")?;
-    let changelog_n = fs::read_dir(changelog_dir.as_path())?.count();
+    let today = run!("date --iso")?;
+    let commit = run!("git rev-parse HEAD")?;
+    let changelog_n = fs2::read_dir(changelog_dir.as_path())?.count();
 
     let contents = format!(
         "\
@@ -193,7 +186,9 @@ Release: release:{}[]
     );
 
     let path = changelog_dir.join(format!("{}-changelog-{}.adoc", today, changelog_n));
-    fs::write(&path, &contents)?;
+    fs2::write(&path, &contents)?;
+
+    fs2::copy(project_root().join("./docs/user/readme.adoc"), website_root.join("manual.adoc"))?;
 
     Ok(())
 }
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 7ca727bde..a7dffe2cc 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -93,8 +93,9 @@ FLAGS:
             run_pre_cache()
         }
         "release" => {
+            let dry_run = args.contains("--dry-run");
             args.finish()?;
-            run_release()
+            run_release(dry_run)
         }
         _ => {
             eprintln!(
diff --git a/xtask/src/not_bash.rs b/xtask/src/not_bash.rs
new file mode 100644
index 000000000..3e30e7279
--- /dev/null
+++ b/xtask/src/not_bash.rs
@@ -0,0 +1,165 @@
+//! A bad shell -- small cross platform module for writing glue code
+use std::{
+    cell::RefCell,
+    env,
+    ffi::OsStr,
+    fs,
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+};
+
+use anyhow::{bail, Context, Result};
+
+pub mod fs2 {
+    use std::{fs, path::Path};
+
+    use anyhow::{Context, Result};
+
+    pub fn read_dir<P: AsRef<Path>>(path: P) -> Result<fs::ReadDir> {
+        let path = path.as_ref();
+        fs::read_dir(path).with_context(|| format!("Failed to read {}", path.display()))
+    }
+
+    pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> Result<()> {
+        let path = path.as_ref();
+        fs::write(path, contents).with_context(|| format!("Failed to write {}", path.display()))
+    }
+
+    pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> Result<u64> {
+        let from = from.as_ref();
+        let to = to.as_ref();
+        fs::copy(from, to)
+            .with_context(|| format!("Failed to copy {} to {}", from.display(), to.display()))
+    }
+
+    pub fn remove_file<P: AsRef<Path>>(path: P) -> Result<()> {
+        let path = path.as_ref();
+        fs::remove_file(path).with_context(|| format!("Failed to remove file {}", path.display()))
+    }
+
+    pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> Result<()> {
+        let path = path.as_ref();
+        fs::remove_dir_all(path).with_context(|| format!("Failed to remove dir {}", path.display()))
+    }
+}
+
+macro_rules! _run {
+    ($($expr:expr),*) => {
+        run!($($expr),*; echo = true)
+    };
+    ($($expr:expr),* ; echo = $echo:expr) => {
+        $crate::not_bash::run_process(format!($($expr),*), $echo)
+    };
+}
+pub(crate) use _run as run;
+
+pub struct Pushd {
+    _p: (),
+}
+
+pub fn pushd(path: impl Into<PathBuf>) -> Pushd {
+    Env::with(|env| env.pushd(path.into()));
+    Pushd { _p: () }
+}
+
+impl Drop for Pushd {
+    fn drop(&mut self) {
+        Env::with(|env| env.popd())
+    }
+}
+
+pub fn rm(glob: &str) -> Result<()> {
+    let cwd = Env::with(|env| env.cwd());
+    ls(glob)?.into_iter().try_for_each(|it| fs::remove_file(cwd.join(it)))?;
+    Ok(())
+}
+
+pub fn rm_rf(path: impl AsRef<Path>) -> Result<()> {
+    let path = path.as_ref();
+    if path.is_file() {
+        fs2::remove_file(path)
+    } else {
+        fs2::remove_dir_all(path)
+    }
+}
+
+pub fn ls(glob: &str) -> Result<Vec<PathBuf>> {
+    let cwd = Env::with(|env| env.cwd());
+    let mut res = Vec::new();
+    for entry in fs::read_dir(&cwd)? {
+        let entry = entry?;
+        if matches(&entry.file_name(), glob) {
+            let path = entry.path();
+            let path = path.strip_prefix(&cwd).unwrap();
+            res.push(path.to_path_buf())
+        }
+    }
+    return Ok(res);
+
+    fn matches(file_name: &OsStr, glob: &str) -> bool {
+        assert!(glob.starts_with('*'));
+        file_name.to_string_lossy().ends_with(&glob[1..])
+    }
+}
+
+#[doc(hidden)]
+pub fn run_process(cmd: String, echo: bool) -> Result<String> {
+    run_process_inner(&cmd, echo).with_context(|| format!("process `{}` failed", cmd))
+}
+
+fn run_process_inner(cmd: &str, echo: bool) -> Result<String> {
+    let cwd = Env::with(|env| env.cwd());
+    let mut args = shelx(cmd);
+    let binary = args.remove(0);
+
+    if echo {
+        println!("> {}", cmd)
+    }
+
+    let output = Command::new(binary)
+        .args(args)
+        .current_dir(cwd)
+        .stdin(Stdio::null())
+        .stderr(Stdio::inherit())
+        .output()?;
+    let stdout = String::from_utf8(output.stdout)?;
+
+    if echo {
+        print!("{}", stdout)
+    }
+
+    if !output.status.success() {
+        bail!("{}", output.status)
+    }
+
+    Ok(stdout.trim().to_string())
+}
+
+// FIXME: some real shell lexing here
+fn shelx(cmd: &str) -> Vec<String> {
+    cmd.split_whitespace().map(|it| it.to_string()).collect()
+}
+
+#[derive(Default)]
+struct Env {
+    pushd_stack: Vec<PathBuf>,
+}
+
+impl Env {
+    fn with<F: FnOnce(&mut Env) -> T, T>(f: F) -> T {
+        thread_local! {
+            static ENV: RefCell<Env> = Default::default();
+        }
+        ENV.with(|it| f(&mut *it.borrow_mut()))
+    }
+
+    fn pushd(&mut self, dir: PathBuf) {
+        self.pushd_stack.push(dir)
+    }
+    fn popd(&mut self) {
+        self.pushd_stack.pop().unwrap();
+    }
+    fn cwd(&self) -> PathBuf {
+        self.pushd_stack.last().cloned().unwrap_or_else(|| env::current_dir().unwrap())
+    }
+}
diff --git a/xtask/src/pre_commit.rs b/xtask/src/pre_commit.rs
index 1533f64dc..056f34acf 100644
--- a/xtask/src/pre_commit.rs
+++ b/xtask/src/pre_commit.rs
@@ -4,18 +4,18 @@ use std::{fs, path::PathBuf};
 
 use anyhow::{bail, Result};
 
-use crate::{cmd::run_with_output, project_root, run, run_rustfmt, Mode};
+use crate::{not_bash::run, project_root, run_rustfmt, Mode};
 
 // FIXME: if there are changed `.ts` files, also reformat TypeScript (by
 // shelling out to `npm fmt`).
 pub fn run_hook() -> Result<()> {
     run_rustfmt(Mode::Overwrite)?;
 
-    let diff = run_with_output("git diff --diff-filter=MAR --name-only --cached", ".")?;
+    let diff = run!("git diff --diff-filter=MAR --name-only --cached")?;
 
     let root = project_root();
     for line in diff.lines() {
-        run(&format!("git update-index --add {}", root.join(line).to_string_lossy()), ".")?;
+        run!("git update-index --add {}", root.join(line).display())?;
     }
 
     Ok(())