105 files changed, 3371 insertions, 1747 deletions

diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 77c92512a..eae4fbcb5 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -95,9 +95,6 @@ jobs:
       - name: Copy vscode extension
         run: mkdir -p ./dist/code && cp ./editors/code/*.vsix ./dist/
 
-      - name: Copy emacs mode
-        run: cp ./editors/emacs/rust-analyzer.el ./dist/rust-analyzer.el
-
       - name: Upload artifacts
         uses: actions/upload-artifact@v1
         with:
@@ -109,6 +106,17 @@ jobs:
     runs-on: ubuntu-latest
     needs: ['build-server', 'build-clients']
     steps:
+      - name: Install Nodejs
+        uses: actions/setup-node@v1
+        with:
+          node-version: 12.x
+
+      - run: echo "::set-env name=TAG::$(date --iso)"
+      - run: 'echo "TAG: $TAG"'
+
+      - name: Checkout repository
+        uses: actions/checkout@v1
+
       - uses: actions/download-artifact@v1
         with:
           name: editor-plugins
@@ -127,9 +135,6 @@ jobs:
           path: dist
       - run: ls -all ./dist
 
-      - run: echo "::set-env name=TAG::$(date --iso)"
-      - run: 'echo "TAG: $TAG"'
-
       - name: Create Release
         id: create_release
         # uses: actions/create-release@v1
@@ -179,11 +184,10 @@ jobs:
           asset_name: rust-analyzer-0.1.0.vsix
           asset_content_type: application/octet-stream
 
-      - uses: actions/[email protected]
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        with:
-          upload_url: ${{ steps.create_release.outputs.upload_url }}
-          asset_path: ./dist/rust-analyzer.el
-          asset_name: rust-analyzer.el
-          asset_content_type: text/plain
+      - run: npm ci
+        working-directory: ./editors/code
+
+      - name: Publish Extension
+        working-directory: ./editors/code
+        # token from https://dev.azure.com/rust-analyzer/
+        run: npx vsce publish 0.1.$(date +%Y%m%d) --pat ${{ secrets.MARKETPLACE_TOKEN }}
diff --git a/.vscode/launch.json b/.vscode/launch.json
index 55a2f10f2..b1bd98d4a 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -2,39 +2,61 @@
   // Use IntelliSense to learn about possible attributes.
   // Hover to view descriptions of existing attributes.
   // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+
+  // NOTE: --disable-extensions
+  // Disable all installed extensions to increase performance of the debug instance
+  // and prevent potential conflicts with other installed extensions.
+
   "version": "0.2.0",
   "configurations": [
     {
+      // Used for testing the extension with the installed LSP server.
       "name": "Run Extension",
       "type": "extensionHost",
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": [
+        "--disable-extensions",
         "--extensionDevelopmentPath=${workspaceFolder}/editors/code"
       ],
       "outFiles": [
         "${workspaceFolder}/editors/code/out/**/*.js"
       ],
-      "preLaunchTask": "Build Extension"
+      "preLaunchTask": "Build Extension",
+      "skipFiles": [
+        "<node_internals>/**/*.js"
+      ]
     },
     {
+      // Used for testing the extension with a local build of the LSP server (in `target/debug`).
       "name": "Run Extension (Dev Server)",
       "type": "extensionHost",
       "request": "launch",
       "runtimeExecutable": "${execPath}",
       "args": [
+        "--disable-extensions",
         "--extensionDevelopmentPath=${workspaceFolder}/editors/code"
       ],
       "outFiles": [
         "${workspaceFolder}/editors/code/out/**/*.js"
       ],
       "preLaunchTask": "Build Extension",
+      "skipFiles": [
+        "<node_internals>/**/*.js"
+      ],
       "env": {
         "__RA_LSP_SERVER_DEBUG": "${workspaceFolder}/target/debug/ra_lsp_server"
       }
     },
     {
-      "name": "Debug Lsp Server",
+      // Used to attach LLDB to a running LSP server.
+      // NOTE: Might require root permissions. For this run:
+      //
+      // `echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope`
+      //
+      // Don't forget to set `debug = 2` in `Cargo.toml` before building the server
+
+      "name": "Attach To Server",
       "type": "lldb",
       "request": "attach",
       "program": "${workspaceFolder}/target/debug/ra_lsp_server",
diff --git a/Cargo.lock b/Cargo.lock
index e29ff898d..f44e514dd 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -110,9 +110,9 @@ dependencies = [
 
 [[package]]
 name = "byteorder"
-version = "1.3.2"
+version = "1.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7c3dd8985a7111efc5c80b44e23ecdd8c007de8ade3b96595387e812b957cf5"
+checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
 
 [[package]]
 name = "c2-chacha"
@@ -1015,6 +1015,7 @@ name = "ra_cli"
 version = "0.1.0"
 dependencies = [
  "env_logger",
+ "itertools",
  "pico-args",
  "ra_batch",
  "ra_db",
@@ -1024,6 +1025,7 @@ dependencies = [
  "ra_ide",
  "ra_prof",
  "ra_syntax",
+ "rand 0.7.3",
 ]
 
 [[package]]
@@ -1070,6 +1072,7 @@ dependencies = [
  "drop_bomb",
  "either",
  "insta",
+ "itertools",
  "log",
  "once_cell",
  "ra_arena",
@@ -1173,7 +1176,6 @@ dependencies = [
  "ra_prof",
  "ra_syntax",
  "ra_text_edit",
- "rand 0.7.3",
  "rayon",
  "rustc-hash",
  "superslice",
@@ -1246,6 +1248,7 @@ dependencies = [
 name = "ra_project_model"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "cargo_metadata",
  "log",
  "ra_arena",
@@ -1563,12 +1566,9 @@ checksum = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
 
 [[package]]
 name = "rustc-hash"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7540fc8b0c49f096ee9c961cda096467dce8084bec6bdca2fc83895fd9b28cb8"
-dependencies = [
- "byteorder",
-]
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
 
 [[package]]
 name = "rustc_lexer"
@@ -1675,9 +1675,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.46"
+version = "1.0.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "21b01d7f0288608a01dca632cf1df859df6fd6ffa885300fc275ce2ba6221953"
+checksum = "15913895b61e0be854afd32fd4163fcd2a3df34142cf2cb961b310ce694cbf90"
 dependencies = [
  "itoa",
  "ryu",
diff --git a/Cargo.toml b/Cargo.toml
index e5620b1b7..c034e2424 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -31,3 +31,8 @@ opt-level = 0
 
 [patch.'crates-io']
 # rowan = { path = "../rowan" }
+
+[patch.'https://github.com/rust-lang/chalk.git']
+# chalk-solve = { path = "../chalk/chalk-solve" }
+# chalk-rust-ir = { path = "../chalk/chalk-rust-ir" }
+# chalk-ir = { path = "../chalk/chalk-ir" }
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_assists/src/handlers/fill_match_arms.rs b/crates/ra_assists/src/handlers/fill_match_arms.rs
index 0908fc246..ae2437ed3 100644
--- a/crates/ra_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ra_assists/src/handlers/fill_match_arms.rs
@@ -75,10 +75,10 @@ pub(crate) fn fill_match_arms(ctx: AssistCtx) -> Option<Assist> {
 }
 
 fn is_trivial(arm: &ast::MatchArm) -> bool {
-    arm.pats().any(|pat| match pat {
-        ast::Pat::PlaceholderPat(..) => true,
+    match arm.pat() {
+        Some(ast::Pat::PlaceholderPat(..)) => true,
         _ => false,
-    })
+    }
 }
 
 fn resolve_enum_def(
diff --git a/crates/ra_assists/src/handlers/merge_match_arms.rs b/crates/ra_assists/src/handlers/merge_match_arms.rs
index 670614dd8..b2a194cb5 100644
--- a/crates/ra_assists/src/handlers/merge_match_arms.rs
+++ b/crates/ra_assists/src/handlers/merge_match_arms.rs
@@ -75,7 +75,7 @@ pub(crate) fn merge_match_arms(ctx: AssistCtx) -> Option<Assist> {
         } else {
             arms_to_merge
                 .iter()
-                .flat_map(ast::MatchArm::pats)
+                .filter_map(ast::MatchArm::pat)
                 .map(|x| x.syntax().to_string())
                 .collect::<Vec<String>>()
                 .join(" | ")
@@ -96,10 +96,10 @@ pub(crate) fn merge_match_arms(ctx: AssistCtx) -> Option<Assist> {
 }
 
 fn contains_placeholder(a: &ast::MatchArm) -> bool {
-    a.pats().any(|x| match x {
-        ra_syntax::ast::Pat::PlaceholderPat(..) => true,
+    match a.pat() {
+        Some(ra_syntax::ast::Pat::PlaceholderPat(..)) => true,
         _ => false,
-    })
+    }
 }
 
 fn next_arm(arm: &ast::MatchArm) -> Option<ast::MatchArm> {
diff --git a/crates/ra_assists/src/handlers/move_guard.rs b/crates/ra_assists/src/handlers/move_guard.rs
index 2b91ce7c4..a61a2ba3e 100644
--- a/crates/ra_assists/src/handlers/move_guard.rs
+++ b/crates/ra_assists/src/handlers/move_guard.rs
@@ -90,7 +90,7 @@ pub(crate) fn move_guard_to_arm_body(ctx: AssistCtx) -> Option<Assist> {
 // ```
 pub(crate) fn move_arm_cond_to_match_guard(ctx: AssistCtx) -> Option<Assist> {
     let match_arm: MatchArm = ctx.find_node_at_offset::<MatchArm>()?;
-    let last_match_pat = match_arm.pats().last()?;
+    let match_pat = match_arm.pat()?;
 
     let arm_body = match_arm.expr()?;
     let if_expr: IfExpr = IfExpr::cast(arm_body.syntax().clone())?;
@@ -122,8 +122,8 @@ pub(crate) fn move_arm_cond_to_match_guard(ctx: AssistCtx) -> Option<Assist> {
                 _ => edit.replace(if_expr.syntax().text_range(), then_block.syntax().text()),
             }
 
-            edit.insert(last_match_pat.syntax().text_range().end(), buf);
-            edit.set_cursor(last_match_pat.syntax().text_range().end() + TextUnit::from(1));
+            edit.insert(match_pat.syntax().text_range().end(), buf);
+            edit.set_cursor(match_pat.syntax().text_range().end() + TextUnit::from(1));
         },
     )
 }
diff --git a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
index b70c88ec2..eac452413 100644
--- a/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
+++ b/crates/ra_assists/src/handlers/replace_qualified_name_with_use.rs
@@ -431,7 +431,12 @@ fn best_action_for_target(
                 .find(|n| n.text_range().start() < anchor.text_range().start())
                 .or_else(|| Some(anchor));
 
-            ImportAction::add_new_use(anchor, false)
+            let add_after_anchor = anchor
+                .clone()
+                .and_then(ast::Attr::cast)
+                .map(|attr| attr.kind() == ast::AttrKind::Inner)
+                .unwrap_or(false);
+            ImportAction::add_new_use(anchor, add_after_anchor)
         }
     }
 }
@@ -962,4 +967,26 @@ mod foo {
     ",
         );
     }
+
+    #[test]
+    fn inserts_imports_after_inner_attributes() {
+        check_assist(
+            replace_qualified_name_with_use,
+            "
+#![allow(dead_code)]
+
+fn main() {
+    std::fmt::Debug<|>
+}
+    ",
+            "
+#![allow(dead_code)]
+use std::fmt::Debug;
+
+fn main() {
+    Debug<|>
+}
+    ",
+        );
+    }
 }
diff --git a/crates/ra_cli/Cargo.toml b/crates/ra_cli/Cargo.toml
index bcd408421..53d4876f6 100644
--- a/crates/ra_cli/Cargo.toml
+++ b/crates/ra_cli/Cargo.toml
@@ -6,8 +6,10 @@ authors = ["rust-analyzer developers"]
 publish = false
 
 [dependencies]
+itertools = "0.8.0"
 pico-args = "0.3.0"
 env_logger = { version = "0.7.1", default-features = false }
+rand = { version = "0.7.0", features = ["small_rng"] }
 
 ra_syntax = { path = "../ra_syntax" }
 ra_ide = { path = "../ra_ide" }
diff --git a/crates/ra_cli/src/analysis_bench.rs b/crates/ra_cli/src/analysis_bench.rs
index 5485a38ff..4835a68ce 100644
--- a/crates/ra_cli/src/analysis_bench.rs
+++ b/crates/ra_cli/src/analysis_bench.rs
@@ -2,6 +2,7 @@
 
 use std::{
     path::{Path, PathBuf},
+    str::FromStr,
     sync::Arc,
     time::Instant,
 };
@@ -14,12 +15,35 @@ use ra_ide::{Analysis, AnalysisChange, AnalysisHost, FilePosition, LineCol};
 
 use crate::Result;
 
+pub(crate) struct Position {
+    path: PathBuf,
+    line: u32,
+    column: u32,
+}
+
+impl FromStr for Position {
+    type Err = Box<dyn std::error::Error + Send + Sync>;
+    fn from_str(s: &str) -> Result<Self> {
+        let (path_line, column) = rsplit_at_char(s, ':')?;
+        let (path, line) = rsplit_at_char(path_line, ':')?;
+        Ok(Position { path: path.into(), line: line.parse()?, column: column.parse()? })
+    }
+}
+
+fn rsplit_at_char(s: &str, c: char) -> Result<(&str, &str)> {
+    let idx = s.rfind(':').ok_or_else(|| format!("no `{}` in {}", c, s))?;
+    Ok((&s[..idx], &s[idx + 1..]))
+}
+
 pub(crate) enum Op {
     Highlight { path: PathBuf },
-    Complete { path: PathBuf, line: u32, column: u32 },
+    Complete(Position),
+    GotoDef(Position),
 }
 
 pub(crate) fn run(verbose: bool, path: &Path, op: Op) -> Result<()> {
+    ra_prof::init();
+
     let start = Instant::now();
     eprint!("loading: ");
     let (mut host, roots) = ra_batch::load_cargo(path)?;
@@ -29,7 +53,7 @@ pub(crate) fn run(verbose: bool, path: &Path, op: Op) -> Result<()> {
     let file_id = {
         let path = match &op {
             Op::Highlight { path } => path,
-            Op::Complete { path, .. } => path,
+            Op::Complete(pos) | Op::GotoDef(pos) => &pos.path,
         };
         let path = std::env::current_dir()?.join(path).canonicalize()?;
         roots
@@ -49,7 +73,7 @@ pub(crate) fn run(verbose: bool, path: &Path, op: Op) -> Result<()> {
             .ok_or_else(|| format!("Can't find {:?}", path))?
     };
 
-    match op {
+    match &op {
         Op::Highlight { .. } => {
             let res = do_work(&mut host, file_id, |analysis| {
                 analysis.diagnostics(file_id).unwrap();
@@ -59,16 +83,30 @@ pub(crate) fn run(verbose: bool, path: &Path, op: Op) -> Result<()> {
                 println!("\n{}", res);
             }
         }
-        Op::Complete { line, column, .. } => {
+        Op::Complete(pos) | Op::GotoDef(pos) => {
+            let is_completion = match op {
+                Op::Complete(..) => true,
+                _ => false,
+            };
+
             let offset = host
                 .analysis()
                 .file_line_index(file_id)?
-                .offset(LineCol { line, col_utf16: column });
+                .offset(LineCol { line: pos.line - 1, col_utf16: pos.column });
             let file_postion = FilePosition { file_id, offset };
 
-            let res = do_work(&mut host, file_id, |analysis| analysis.completions(file_postion));
-            if verbose {
-                println!("\n{:#?}", res);
+            if is_completion {
+                let res =
+                    do_work(&mut host, file_id, |analysis| analysis.completions(file_postion));
+                if verbose {
+                    println!("\n{:#?}", res);
+                }
+            } else {
+                let res =
+                    do_work(&mut host, file_id, |analysis| analysis.goto_definition(file_postion));
+                if verbose {
+                    println!("\n{:#?}", res);
+                }
             }
         }
     }
diff --git a/crates/ra_cli/src/analysis_stats.rs b/crates/ra_cli/src/analysis_stats.rs
index 833235bff..6d2dd34c6 100644
--- a/crates/ra_cli/src/analysis_stats.rs
+++ b/crates/ra_cli/src/analysis_stats.rs
@@ -2,6 +2,9 @@
 
 use std::{collections::HashSet, fmt::Write, path::Path, time::Instant};
 
+use itertools::Itertools;
+use rand::{seq::SliceRandom, thread_rng};
+
 use hir::{
     db::{DefDatabase, HirDatabase},
     AssocItem, Crate, HasSource, HirDisplay, ModuleDef,
@@ -19,6 +22,7 @@ pub fn run(
     path: &Path,
     only: Option<&str>,
     with_deps: bool,
+    randomize: bool,
 ) -> Result<()> {
     let db_load_time = Instant::now();
     let (mut host, roots) = ra_batch::load_cargo(path)?;
@@ -41,7 +45,11 @@ pub fn run(
             })
             .collect::<HashSet<_>>();
 
-    for krate in Crate::all(db) {
+    let mut krates = Crate::all(db);
+    if randomize {
+        krates.shuffle(&mut thread_rng());
+    }
+    for krate in krates {
         let module = krate.root_module(db).expect("crate without root module");
         let file_id = module.definition_source(db).file_id;
         if members.contains(&db.file_source_root(file_id.original_file(db))) {
@@ -50,6 +58,10 @@ pub fn run(
         }
     }
 
+    if randomize {
+        visit_queue.shuffle(&mut thread_rng());
+    }
+
     println!("Crates in this dir: {}", num_crates);
     let mut num_decls = 0;
     let mut funcs = Vec::new();
@@ -79,10 +91,14 @@ pub fn run(
     println!("Total functions: {}", funcs.len());
     println!("Item Collection: {:?}, {}", analysis_time.elapsed(), ra_prof::memory_usage());
 
+    if randomize {
+        funcs.shuffle(&mut thread_rng());
+    }
+
     let inference_time = Instant::now();
     let mut bar = match verbosity {
-        Verbosity::Verbose | Verbosity::Normal => ProgressReport::new(funcs.len() as u64),
-        Verbosity::Quiet => ProgressReport::hidden(),
+        Verbosity::Quiet | Verbosity::Spammy => ProgressReport::hidden(),
+        _ => ProgressReport::new(funcs.len() as u64),
     };
 
     bar.tick();
@@ -92,7 +108,20 @@ pub fn run(
     let mut num_type_mismatches = 0;
     for f in funcs {
         let name = f.name(db);
-        let mut msg = format!("processing: {}", name);
+        let full_name = f
+            .module(db)
+            .path_to_root(db)
+            .into_iter()
+            .rev()
+            .filter_map(|it| it.name(db))
+            .chain(Some(f.name(db)))
+            .join("::");
+        if let Some(only_name) = only {
+            if name.to_string() != only_name && full_name != only_name {
+                continue;
+            }
+        }
+        let mut msg = format!("processing: {}", full_name);
         if verbosity.is_verbose() {
             let src = f.source(db);
             let original_file = src.file_id.original_file(db);
@@ -100,15 +129,15 @@ pub fn run(
             let syntax_range = src.value.syntax().text_range();
             write!(msg, " ({:?} {})", path, syntax_range).unwrap();
         }
-        bar.set_message(&msg);
-        if let Some(only_name) = only {
-            if name.to_string() != only_name {
-                continue;
-            }
+        if verbosity.is_spammy() {
+            bar.println(format!("{}", msg));
         }
+        bar.set_message(&msg);
         let f_id = FunctionId::from(f);
         let body = db.body(f_id.into());
         let inference_result = db.infer(f_id.into());
+        let (previous_exprs, previous_unknown, previous_partially_unknown) =
+            (num_exprs, num_exprs_unknown, num_exprs_partially_unknown);
         for (expr_id, _) in body.exprs.iter() {
             let ty = &inference_result[expr_id];
             num_exprs += 1;
@@ -125,6 +154,33 @@ pub fn run(
                     num_exprs_partially_unknown += 1;
                 }
             }
+            if only.is_some() && verbosity.is_spammy() {
+                // in super-verbose mode for just one function, we print every single expression
+                let (_, sm) = db.body_with_source_map(f_id.into());
+                let src = sm.expr_syntax(expr_id);
+                if let Some(src) = src {
+                    let original_file = src.file_id.original_file(db);
+                    let line_index = host.analysis().file_line_index(original_file).unwrap();
+                    let text_range = src.value.either(
+                        |it| it.syntax_node_ptr().range(),
+                        |it| it.syntax_node_ptr().range(),
+                    );
+                    let (start, end) = (
+                        line_index.line_col(text_range.start()),
+                        line_index.line_col(text_range.end()),
+                    );
+                    bar.println(format!(
+                        "{}:{}-{}:{}: {}",
+                        start.line + 1,
+                        start.col_utf16,
+                        end.line + 1,
+                        end.col_utf16,
+                        ty.display(db)
+                    ));
+                } else {
+                    bar.println(format!("unknown location: {}", ty.display(db)));
+                }
+            }
             if let Some(mismatch) = inference_result.type_mismatch_for_expr(expr_id) {
                 num_type_mismatches += 1;
                 if verbosity.is_verbose() {
@@ -164,6 +220,15 @@ pub fn run(
                 }
             }
         }
+        if verbosity.is_spammy() {
+            bar.println(format!(
+                "In {}: {} exprs, {} unknown, {} partial",
+                full_name,
+                num_exprs - previous_exprs,
+                num_exprs_unknown - previous_unknown,
+                num_exprs_partially_unknown - previous_partially_unknown
+            ));
+        }
         bar.inc(1);
     }
     bar.finish_and_clear();
diff --git a/crates/ra_cli/src/main.rs b/crates/ra_cli/src/main.rs
index 806612c2c..750cbab86 100644
--- a/crates/ra_cli/src/main.rs
+++ b/crates/ra_cli/src/main.rs
@@ -16,6 +16,7 @@ type Result<T> = std::result::Result<T, Box<dyn Error + Send + Sync>>;
 
 #[derive(Clone, Copy)]
 pub enum Verbosity {
+    Spammy,
     Verbose,
     Normal,
     Quiet,
@@ -24,7 +25,13 @@ pub enum Verbosity {
 impl Verbosity {
     fn is_verbose(self) -> bool {
         match self {
-            Verbosity::Verbose => true,
+            Verbosity::Verbose | Verbosity::Spammy => true,
+            _ => false,
+        }
+    }
+    fn is_spammy(self) -> bool {
+        match self {
+            Verbosity::Spammy => true,
             _ => false,
         }
     }
@@ -86,14 +93,18 @@ fn main() -> Result<()> {
                 return Ok(());
             }
             let verbosity = match (
+                matches.contains(["-vv", "--spammy"]),
                 matches.contains(["-v", "--verbose"]),
                 matches.contains(["-q", "--quiet"]),
             ) {
-                (false, false) => Verbosity::Normal,
-                (false, true) => Verbosity::Quiet,
-                (true, false) => Verbosity::Verbose,
-                (true, true) => Err("Invalid flags: -q conflicts with -v")?,
+                (true, _, true) => Err("Invalid flags: -q conflicts with -vv")?,
+                (true, _, false) => Verbosity::Spammy,
+                (false, false, false) => Verbosity::Normal,
+                (false, false, true) => Verbosity::Quiet,
+                (false, true, false) => Verbosity::Verbose,
+                (false, true, true) => Err("Invalid flags: -q conflicts with -v")?,
             };
+            let randomize = matches.contains("--randomize");
             let memory_usage = matches.contains("--memory-usage");
             let only: Option<String> = matches.opt_value_from_str(["-o", "--only"])?;
             let with_deps: bool = matches.contains("--with-deps");
@@ -111,6 +122,7 @@ fn main() -> Result<()> {
                 path.as_ref(),
                 only.as_ref().map(String::as_ref),
                 with_deps,
+                randomize,
             )?;
         }
         "analysis-bench" => {
@@ -120,25 +132,16 @@ fn main() -> Result<()> {
             }
             let verbose = matches.contains(["-v", "--verbose"]);
             let path: String = matches.opt_value_from_str("--path")?.unwrap_or_default();
-            let highlight_path = matches.opt_value_from_str("--highlight")?;
-            let complete_path = matches.opt_value_from_str("--complete")?;
-            if highlight_path.is_some() && complete_path.is_some() {
-                panic!("either --highlight or --complete must be set, not both")
-            }
-            let op = if let Some(path) = highlight_path {
-                let path: String = path;
-                analysis_bench::Op::Highlight { path: path.into() }
-            } else if let Some(path_line_col) = complete_path {
-                let path_line_col: String = path_line_col;
-                let (path_line, column) = rsplit_at_char(path_line_col.as_str(), ':')?;
-                let (path, line) = rsplit_at_char(path_line, ':')?;
-                analysis_bench::Op::Complete {
-                    path: path.into(),
-                    line: line.parse()?,
-                    column: column.parse()?,
-                }
-            } else {
-                panic!("either --highlight or --complete must be set")
+            let highlight_path: Option<String> = matches.opt_value_from_str("--highlight")?;
+            let complete_path: Option<String> = matches.opt_value_from_str("--complete")?;
+            let goto_def_path: Option<String> = matches.opt_value_from_str("--goto-def")?;
+            let op = match (highlight_path, complete_path, goto_def_path) {
+                (Some(path), None, None) => analysis_bench::Op::Highlight { path: path.into() },
+                (None, Some(position), None) => analysis_bench::Op::Complete(position.parse()?),
+                (None, None, Some(position)) => analysis_bench::Op::GotoDef(position.parse()?),
+                _ => panic!(
+                    "exactly one of  `--highlight`, `--complete` or `--goto-def` must be set"
+                ),
             };
             matches.finish().or_else(handle_extra_flags)?;
             analysis_bench::run(verbose, path.as_ref(), op)?;
@@ -171,8 +174,3 @@ fn read_stdin() -> Result<String> {
     std::io::stdin().read_to_string(&mut buff)?;
     Ok(buff)
 }
-
-fn rsplit_at_char(s: &str, c: char) -> Result<(&str, &str)> {
-    let idx = s.rfind(':').ok_or_else(|| format!("no `{}` in {}", c, s))?;
-    Ok((&s[..idx], &s[idx + 1..]))
-}
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 4d9641728..a56b8ab04 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -10,9 +10,9 @@ use hir_def::{
     per_ns::PerNs,
     resolver::HasResolver,
     type_ref::{Mutability, TypeRef},
-    AdtId, ConstId, DefWithBodyId, EnumId, FunctionId, GenericDefId, HasModule, ImplId,
-    LocalEnumVariantId, LocalModuleId, LocalStructFieldId, Lookup, ModuleId, StaticId, StructId,
-    TraitId, TypeAliasId, TypeParamId, UnionId,
+    AdtId, AssocContainerId, ConstId, DefWithBodyId, EnumId, FunctionId, GenericDefId, HasModule,
+    ImplId, LocalEnumVariantId, LocalModuleId, LocalStructFieldId, Lookup, ModuleId, StaticId,
+    StructId, TraitId, TypeAliasId, TypeParamId, UnionId,
 };
 use hir_expand::{
     diagnostics::DiagnosticSink,
@@ -25,7 +25,10 @@ use hir_ty::{
 };
 use ra_db::{CrateId, Edition, FileId};
 use ra_prof::profile;
-use ra_syntax::ast::{self, AttrsOwner};
+use ra_syntax::{
+    ast::{self, AttrsOwner},
+    AstNode,
+};
 
 use crate::{
     db::{DefDatabase, HirDatabase},
@@ -119,7 +122,9 @@ impl_froms!(
     BuiltinType
 );
 
-pub use hir_def::{attr::Attrs, item_scope::ItemInNs, visibility::Visibility, AssocItemId};
+pub use hir_def::{
+    attr::Attrs, item_scope::ItemInNs, visibility::Visibility, AssocItemId, AssocItemLoc,
+};
 use rustc_hash::FxHashSet;
 
 impl Module {
@@ -639,17 +644,49 @@ pub struct MacroDef {
     pub(crate) id: MacroDefId,
 }
 
+/// Invariant: `inner.as_assoc_item(db).is_some()`
+/// We do not actively enforce this invariant.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum AssocItem {
     Function(Function),
     Const(Const),
     TypeAlias(TypeAlias),
 }
-// FIXME: not every function, ... is actually an assoc item. maybe we should make
-// sure that you can only turn actual assoc items into AssocItems. This would
-// require not implementing From, and instead having some checked way of
-// casting them, and somehow making the constructors private, which would be annoying.
-impl_froms!(AssocItem: Function, Const, TypeAlias);
+pub enum AssocItemContainer {
+    Trait(Trait),
+    ImplBlock(ImplBlock),
+}
+pub trait AsAssocItem {
+    fn as_assoc_item(self, db: &impl DefDatabase) -> Option<AssocItem>;
+}
+
+impl AsAssocItem for Function {
+    fn as_assoc_item(self, db: &impl DefDatabase) -> Option<AssocItem> {
+        as_assoc_item(db, AssocItem::Function, self.id)
+    }
+}
+impl AsAssocItem for Const {
+    fn as_assoc_item(self, db: &impl DefDatabase) -> Option<AssocItem> {
+        as_assoc_item(db, AssocItem::Const, self.id)
+    }
+}
+impl AsAssocItem for TypeAlias {
+    fn as_assoc_item(self, db: &impl DefDatabase) -> Option<AssocItem> {
+        as_assoc_item(db, AssocItem::TypeAlias, self.id)
+    }
+}
+fn as_assoc_item<ID, DEF, CTOR, AST>(db: &impl DefDatabase, ctor: CTOR, id: ID) -> Option<AssocItem>
+where
+    ID: Lookup<Data = AssocItemLoc<AST>>,
+    DEF: From<ID>,
+    CTOR: FnOnce(DEF) -> AssocItem,
+    AST: AstNode,
+{
+    match id.lookup(db).container {
+        AssocContainerId::TraitId(_) | AssocContainerId::ImplId(_) => Some(ctor(DEF::from(id))),
+        AssocContainerId::ContainerId(_) => None,
+    }
+}
 
 impl AssocItem {
     pub fn module(self, db: &impl DefDatabase) -> Module {
@@ -659,6 +696,18 @@ impl AssocItem {
             AssocItem::TypeAlias(t) => t.module(db),
         }
     }
+    pub fn container(self, db: &impl DefDatabase) -> AssocItemContainer {
+        let container = match self {
+            AssocItem::Function(it) => it.id.lookup(db).container,
+            AssocItem::Const(it) => it.id.lookup(db).container,
+            AssocItem::TypeAlias(it) => it.id.lookup(db).container,
+        };
+        match container {
+            AssocContainerId::TraitId(id) => AssocItemContainer::Trait(id.into()),
+            AssocContainerId::ImplId(id) => AssocItemContainer::ImplBlock(id.into()),
+            AssocContainerId::ContainerId(_) => panic!("invalid AssocItem"),
+        }
+    }
 }
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
@@ -769,6 +818,7 @@ impl TypeParam {
     }
 }
 
+// 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/src/lib.rs b/crates/ra_hir/src/lib.rs
index e1c7b7a20..5cd965f7a 100644
--- a/crates/ra_hir/src/lib.rs
+++ b/crates/ra_hir/src/lib.rs
@@ -39,10 +39,10 @@ mod has_source;
 
 pub use crate::{
     code_model::{
-        Adt, AssocItem, AttrDef, Const, Crate, CrateDependency, DefWithBody, Docs, Enum,
-        EnumVariant, FieldSource, Function, GenericDef, HasAttrs, HasVisibility, ImplBlock, Local,
-        MacroDef, Module, ModuleDef, ScopeDef, Static, Struct, StructField, Trait, Type, TypeAlias,
-        TypeParam, Union, VariantDef,
+        Adt, AsAssocItem, AssocItem, AssocItemContainer, AttrDef, Const, Crate, CrateDependency,
+        DefWithBody, Docs, Enum, EnumVariant, FieldSource, Function, GenericDef, HasAttrs,
+        HasVisibility, ImplBlock, Local, MacroDef, Module, ModuleDef, ScopeDef, Static, Struct,
+        StructField, Trait, Type, TypeAlias, TypeParam, Union, VariantDef,
     },
     has_source::HasSource,
     source_analyzer::{PathResolution, ScopeEntryWithSyntax, SourceAnalyzer},
diff --git a/crates/ra_hir/src/source_analyzer.rs b/crates/ra_hir/src/source_analyzer.rs
index bb9a35c5d..94d5b4cfd 100644
--- a/crates/ra_hir/src/source_analyzer.rs
+++ b/crates/ra_hir/src/source_analyzer.rs
@@ -15,11 +15,9 @@ use hir_def::{
     },
     expr::{ExprId, PatId},
     resolver::{self, resolver_for_scope, Resolver, TypeNs, ValueNs},
-    DefWithBodyId, TraitId,
-};
-use hir_expand::{
-    hygiene::Hygiene, name::AsName, AstId, HirFileId, InFile, MacroCallId, MacroCallKind,
+    AsMacroCall, DefWithBodyId, TraitId,
 };
+use hir_expand::{hygiene::Hygiene, name::AsName, HirFileId, InFile, MacroCallId};
 use hir_ty::{InEnvironment, InferenceResult, TraitEnvironment};
 use ra_syntax::{
     ast::{self, AstNode},
@@ -363,12 +361,10 @@ impl SourceAnalyzer {
         db: &impl HirDatabase,
         macro_call: InFile<&ast::MacroCall>,
     ) -> Option<Expansion> {
-        let def = self.resolve_macro_call(db, macro_call)?.id;
-        let ast_id = AstId::new(
-            macro_call.file_id,
-            db.ast_id_map(macro_call.file_id).ast_id(macro_call.value),
-        );
-        Some(Expansion { macro_call_id: def.as_call_id(db, MacroCallKind::FnLike(ast_id)) })
+        let macro_call_id = macro_call.as_call_id(db, |path| {
+            self.resolver.resolve_path_as_macro(db, &path).map(|it| it.into())
+        })?;
+        Some(Expansion { macro_call_id })
     }
 }
 
diff --git a/crates/ra_hir_def/Cargo.toml b/crates/ra_hir_def/Cargo.toml
index 1efa00fe0..6b9be9948 100644
--- a/crates/ra_hir_def/Cargo.toml
+++ b/crates/ra_hir_def/Cargo.toml
@@ -14,6 +14,7 @@ rustc-hash = "1.0"
 either = "1.5"
 anymap = "0.12"
 drop_bomb = "0.1.4"
+itertools = "0.8.2"
 
 ra_arena = { path = "../ra_arena" }
 ra_db = { path = "../ra_db" }
diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
index 142c52d35..010d35e55 100644
--- a/crates/ra_hir_def/src/body.rs
+++ b/crates/ra_hir_def/src/body.rs
@@ -7,9 +7,7 @@ use std::{mem, ops::Index, sync::Arc};
 
 use drop_bomb::DropBomb;
 use either::Either;
-use hir_expand::{
-    ast_id_map::AstIdMap, hygiene::Hygiene, AstId, HirFileId, InFile, MacroCallKind, MacroDefId,
-};
+use hir_expand::{ast_id_map::AstIdMap, hygiene::Hygiene, AstId, HirFileId, InFile, MacroDefId};
 use ra_arena::{map::ArenaMap, Arena};
 use ra_prof::profile;
 use ra_syntax::{ast, AstNode, AstPtr};
@@ -23,7 +21,7 @@ use crate::{
     nameres::CrateDefMap,
     path::{ModPath, Path},
     src::HasSource,
-    DefWithBodyId, HasModule, Lookup, ModuleId,
+    AsMacroCall, DefWithBodyId, HasModule, Lookup, ModuleId,
 };
 
 pub(crate) struct Expander {
@@ -51,30 +49,26 @@ impl Expander {
         db: &DB,
         macro_call: ast::MacroCall,
     ) -> Option<(Mark, T)> {
-        let ast_id = AstId::new(
-            self.current_file_id,
-            db.ast_id_map(self.current_file_id).ast_id(&macro_call),
-        );
-
-        if let Some(path) = macro_call.path().and_then(|path| self.parse_mod_path(path)) {
-            if let Some(def) = self.resolve_path_as_macro(db, &path) {
-                let call_id = def.as_call_id(db, MacroCallKind::FnLike(ast_id));
-                let file_id = call_id.as_file();
-                if let Some(node) = db.parse_or_expand(file_id) {
-                    if let Some(expr) = T::cast(node) {
-                        log::debug!("macro expansion {:#?}", expr.syntax());
-
-                        let mark = Mark {
-                            file_id: self.current_file_id,
-                            ast_id_map: mem::take(&mut self.ast_id_map),
-                            bomb: DropBomb::new("expansion mark dropped"),
-                        };
-                        self.hygiene = Hygiene::new(db, file_id);
-                        self.current_file_id = file_id;
-                        self.ast_id_map = db.ast_id_map(file_id);
-
-                        return Some((mark, expr));
-                    }
+        let macro_call = InFile::new(self.current_file_id, &macro_call);
+
+        if let Some(call_id) =
+            macro_call.as_call_id(db, |path| self.resolve_path_as_macro(db, &path))
+        {
+            let file_id = call_id.as_file();
+            if let Some(node) = db.parse_or_expand(file_id) {
+                if let Some(expr) = T::cast(node) {
+                    log::debug!("macro expansion {:#?}", expr.syntax());
+
+                    let mark = Mark {
+                        file_id: self.current_file_id,
+                        ast_id_map: mem::take(&mut self.ast_id_map),
+                        bomb: DropBomb::new("expansion mark dropped"),
+                    };
+                    self.hygiene = Hygiene::new(db, file_id);
+                    self.current_file_id = file_id;
+                    self.ast_id_map = db.ast_id_map(file_id);
+
+                    return Some((mark, expr));
                 }
             }
         }
@@ -99,10 +93,6 @@ impl Expander {
         Path::from_src(path, &self.hygiene)
     }
 
-    fn parse_mod_path(&mut self, path: ast::Path) -> Option<ModPath> {
-        ModPath::from_src(path, &self.hygiene)
-    }
-
     fn resolve_path_as_macro(&self, db: &impl DefDatabase, path: &ModPath) -> Option<MacroDefId> {
         self.crate_def_map
             .resolve_path(db, self.module.local_id, path, BuiltinShadowMode::Other)
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index e656f9a41..1fc892362 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -8,7 +8,7 @@ use ra_arena::Arena;
 use ra_syntax::{
     ast::{
         self, ArgListOwner, ArrayExprKind, LiteralKind, LoopBodyOwner, ModuleItemOwner, NameOwner,
-        TypeAscriptionOwner,
+        SlicePatComponents, TypeAscriptionOwner,
     },
     AstNode, AstPtr,
 };
@@ -164,9 +164,9 @@ where
                             let match_expr = self.collect_expr_opt(condition.expr());
                             let placeholder_pat = self.missing_pat();
                             let arms = vec![
-                                MatchArm { pats: vec![pat], expr: then_branch, guard: None },
+                                MatchArm { pat, expr: then_branch, guard: None },
                                 MatchArm {
-                                    pats: vec![placeholder_pat],
+                                    pat: placeholder_pat,
                                     expr: else_branch.unwrap_or_else(|| self.empty_block()),
                                     guard: None,
                                 },
@@ -203,8 +203,8 @@ where
                             let placeholder_pat = self.missing_pat();
                             let break_ = self.alloc_expr_desugared(Expr::Break { expr: None });
                             let arms = vec![
-                                MatchArm { pats: vec![pat], expr: body, guard: None },
-                                MatchArm { pats: vec![placeholder_pat], expr: break_, guard: None },
+                                MatchArm { pat, expr: body, guard: None },
+                                MatchArm { pat: placeholder_pat, expr: break_, guard: None },
                             ];
                             let match_expr =
                                 self.alloc_expr_desugared(Expr::Match { expr: match_expr, arms });
@@ -250,7 +250,7 @@ where
                     match_arm_list
                         .arms()
                         .map(|arm| MatchArm {
-                            pats: arm.pats().map(|p| self.collect_pat(p)).collect(),
+                            pat: self.collect_pat_opt(arm.pat()),
                             expr: self.collect_expr_opt(arm.expr()),
                             guard: arm
                                 .guard()
@@ -587,11 +587,16 @@ where
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
                 path.map(Pat::Path).unwrap_or(Pat::Missing)
             }
+            ast::Pat::OrPat(p) => {
+                let pats = p.pats().map(|p| self.collect_pat(p)).collect();
+                Pat::Or(pats)
+            }
+            ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat()),
             ast::Pat::TuplePat(p) => {
                 let args = p.args().map(|p| self.collect_pat(p)).collect();
                 Pat::Tuple(args)
             }
-            ast::Pat::PlaceholderPat(_) => Pat::Wild,
+            ast::Pat::PlaceholderPat(_) | ast::Pat::DotDotPat(_) => Pat::Wild,
             ast::Pat::RecordPat(p) => {
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
                 let record_field_pat_list =
@@ -616,12 +621,20 @@ where
 
                 Pat::Record { path, args: fields }
             }
+            ast::Pat::SlicePat(p) => {
+                let SlicePatComponents { prefix, slice, suffix } = p.components();
+
+                Pat::Slice {
+                    prefix: prefix.into_iter().map(|p| self.collect_pat(p)).collect(),
+                    slice: slice.map(|p| self.collect_pat(p)),
+                    suffix: suffix.into_iter().map(|p| self.collect_pat(p)).collect(),
+                }
+            }
 
             // FIXME: implement
-            ast::Pat::DotDotPat(_) => Pat::Missing,
             ast::Pat::BoxPat(_) => Pat::Missing,
             ast::Pat::LiteralPat(_) => Pat::Missing,
-            ast::Pat::SlicePat(_) | ast::Pat::RangePat(_) => Pat::Missing,
+            ast::Pat::RangePat(_) => Pat::Missing,
         };
         let ptr = AstPtr::new(&pat);
         self.alloc_pat(pattern, Either::Left(ptr))
diff --git a/crates/ra_hir_def/src/body/scope.rs b/crates/ra_hir_def/src/body/scope.rs
index a63552327..a58a7b21f 100644
--- a/crates/ra_hir_def/src/body/scope.rs
+++ b/crates/ra_hir_def/src/body/scope.rs
@@ -158,9 +158,7 @@ fn compute_expr_scopes(expr: ExprId, body: &Body, scopes: &mut ExprScopes, scope
             compute_expr_scopes(*expr, body, scopes, scope);
             for arm in arms {
                 let scope = scopes.new_scope(scope);
-                for pat in &arm.pats {
-                    scopes.add_bindings(body, scope, *pat);
-                }
+                scopes.add_bindings(body, scope, arm.pat);
                 scopes.set_scope(arm.expr, scope);
                 compute_expr_scopes(arm.expr, body, scopes, scope);
             }
@@ -194,7 +192,7 @@ mod tests {
         let (off, code) = extract_offset(code);
         let code = {
             let mut buf = String::new();
-            let off = u32::from(off) as usize;
+            let off = off.to_usize();
             buf.push_str(&code[..off]);
             buf.push_str("marker");
             buf.push_str(&code[off..]);
diff --git a/crates/ra_hir_def/src/expr.rs b/crates/ra_hir_def/src/expr.rs
index a75ef9970..9707c5527 100644
--- a/crates/ra_hir_def/src/expr.rs
+++ b/crates/ra_hir_def/src/expr.rs
@@ -202,7 +202,7 @@ pub enum Array {
 
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct MatchArm {
-    pub pats: Vec<PatId>,
+    pub pat: PatId,
     pub guard: Option<ExprId>,
     pub expr: ExprId,
 }
@@ -382,6 +382,7 @@ pub enum Pat {
     Missing,
     Wild,
     Tuple(Vec<PatId>),
+    Or(Vec<PatId>),
     Record {
         path: Option<Path>,
         args: Vec<RecordFieldPat>,
@@ -393,7 +394,7 @@ pub enum Pat {
     },
     Slice {
         prefix: Vec<PatId>,
-        rest: Option<PatId>,
+        slice: Option<PatId>,
         suffix: Vec<PatId>,
     },
     Path(Path),
@@ -420,12 +421,12 @@ impl Pat {
             Pat::Bind { subpat, .. } => {
                 subpat.iter().copied().for_each(f);
             }
-            Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
+            Pat::Or(args) | Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
                 args.iter().copied().for_each(f);
             }
             Pat::Ref { pat, .. } => f(*pat),
-            Pat::Slice { prefix, rest, suffix } => {
-                let total_iter = prefix.iter().chain(rest.iter()).chain(suffix.iter());
+            Pat::Slice { prefix, slice, suffix } => {
+                let total_iter = prefix.iter().chain(slice.iter()).chain(suffix.iter());
                 total_iter.copied().for_each(f);
             }
             Pat::Record { args, .. } => {
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index feb3a300d..aa0b558b8 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -46,7 +46,10 @@ mod marks;
 
 use std::hash::Hash;
 
-use hir_expand::{ast_id_map::FileAstId, AstId, HirFileId, InFile, MacroDefId};
+use hir_expand::{
+    ast_id_map::FileAstId, db::AstDatabase, hygiene::Hygiene, AstId, HirFileId, InFile,
+    MacroCallId, MacroCallKind, MacroDefId,
+};
 use ra_arena::{impl_arena_id, RawId};
 use ra_db::{impl_intern_key, salsa, CrateId};
 use ra_syntax::{ast, AstNode};
@@ -413,3 +416,61 @@ impl HasModule for StaticLoc {
         self.container.module(db)
     }
 }
+
+/// A helper trait for converting to MacroCallId
+pub trait AsMacroCall {
+    fn as_call_id(
+        &self,
+        db: &(impl db::DefDatabase + AstDatabase),
+        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+    ) -> Option<MacroCallId>;
+}
+
+impl AsMacroCall for InFile<&ast::MacroCall> {
+    fn as_call_id(
+        &self,
+        db: &(impl db::DefDatabase + AstDatabase),
+        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+    ) -> Option<MacroCallId> {
+        let ast_id = AstId::new(self.file_id, db.ast_id_map(self.file_id).ast_id(self.value));
+        let h = Hygiene::new(db, self.file_id);
+        let path = path::ModPath::from_src(self.value.path()?, &h)?;
+
+        AstIdWithPath::new(ast_id.file_id, ast_id.value, path).as_call_id(db, resolver)
+    }
+}
+
+/// Helper wrapper for `AstId` with `ModPath`
+#[derive(Clone, Debug, Eq, PartialEq)]
+struct AstIdWithPath<T: ast::AstNode> {
+    pub ast_id: AstId<T>,
+    pub path: path::ModPath,
+}
+
+impl<T: ast::AstNode> AstIdWithPath<T> {
+    pub fn new(file_id: HirFileId, ast_id: FileAstId<T>, path: path::ModPath) -> AstIdWithPath<T> {
+        AstIdWithPath { ast_id: AstId::new(file_id, ast_id), path }
+    }
+}
+
+impl AsMacroCall for AstIdWithPath<ast::MacroCall> {
+    fn as_call_id(
+        &self,
+        db: &impl AstDatabase,
+        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+    ) -> Option<MacroCallId> {
+        let def = resolver(self.path.clone())?;
+        Some(def.as_call_id(db, MacroCallKind::FnLike(self.ast_id.clone())))
+    }
+}
+
+impl AsMacroCall for AstIdWithPath<ast::ModuleItem> {
+    fn as_call_id(
+        &self,
+        db: &impl AstDatabase,
+        resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
+    ) -> Option<MacroCallId> {
+        let def = resolver(self.path.clone())?;
+        Some(def.as_call_id(db, MacroCallKind::Attr(self.ast_id.clone())))
+    }
+}
diff --git a/crates/ra_hir_def/src/nameres/collector.rs b/crates/ra_hir_def/src/nameres/collector.rs
index 6352c71ef..51c65a5d7 100644
--- a/crates/ra_hir_def/src/nameres/collector.rs
+++ b/crates/ra_hir_def/src/nameres/collector.rs
@@ -7,7 +7,7 @@ use hir_expand::{
     builtin_derive::find_builtin_derive,
     builtin_macro::find_builtin_macro,
     name::{name, AsName, Name},
-    HirFileId, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    HirFileId, MacroCallId, MacroDefId, MacroDefKind,
 };
 use ra_cfg::CfgOptions;
 use ra_db::{CrateId, FileId};
@@ -25,8 +25,9 @@ use crate::{
     path::{ImportAlias, ModPath, PathKind},
     per_ns::PerNs,
     visibility::Visibility,
-    AdtId, AstId, ConstLoc, ContainerId, EnumLoc, EnumVariantId, FunctionLoc, ImplLoc, Intern,
-    LocalModuleId, ModuleDefId, ModuleId, StaticLoc, StructLoc, TraitLoc, TypeAliasLoc, UnionLoc,
+    AdtId, AsMacroCall, AstId, AstIdWithPath, ConstLoc, ContainerId, EnumLoc, EnumVariantId,
+    FunctionLoc, ImplLoc, Intern, LocalModuleId, ModuleDefId, ModuleId, StaticLoc, StructLoc,
+    TraitLoc, TypeAliasLoc, UnionLoc,
 };
 
 pub(super) fn collect_defs(db: &impl DefDatabase, mut def_map: CrateDefMap) -> CrateDefMap {
@@ -99,11 +100,16 @@ struct ImportDirective {
 #[derive(Clone, Debug, Eq, PartialEq)]
 struct MacroDirective {
     module_id: LocalModuleId,
-    ast_id: AstId<ast::MacroCall>,
-    path: ModPath,
+    ast_id: AstIdWithPath<ast::MacroCall>,
     legacy: Option<MacroCallId>,
 }
 
+#[derive(Clone, Debug, Eq, PartialEq)]
+struct DeriveDirective {
+    module_id: LocalModuleId,
+    ast_id: AstIdWithPath<ast::ModuleItem>,
+}
+
 /// Walks the tree of module recursively
 struct DefCollector<'a, DB> {
     db: &'a DB,
@@ -112,7 +118,7 @@ struct DefCollector<'a, DB> {
     unresolved_imports: Vec<ImportDirective>,
     resolved_imports: Vec<ImportDirective>,
     unexpanded_macros: Vec<MacroDirective>,
-    unexpanded_attribute_macros: Vec<(LocalModuleId, AstId<ast::ModuleItem>, ModPath)>,
+    unexpanded_attribute_macros: Vec<DeriveDirective>,
     mod_dirs: FxHashMap<LocalModuleId, ModDir>,
     cfg_options: &'a CfgOptions,
 }
@@ -146,7 +152,7 @@ where
                 ReachedFixedPoint::Yes => break,
                 ReachedFixedPoint::No => i += 1,
             }
-            if i == 1000 {
+            if i == 10000 {
                 log::error!("name resolution is stuck");
                 break;
             }
@@ -515,16 +521,16 @@ where
                 return false;
             }
 
-            let resolved_res = self.def_map.resolve_path_fp_with_macro(
-                self.db,
-                ResolveMode::Other,
-                directive.module_id,
-                &directive.path,
-                BuiltinShadowMode::Module,
-            );
-
-            if let Some(def) = resolved_res.resolved_def.take_macros() {
-                let call_id = def.as_call_id(self.db, MacroCallKind::FnLike(directive.ast_id));
+            if let Some(call_id) = directive.ast_id.as_call_id(self.db, |path| {
+                let resolved_res = self.def_map.resolve_path_fp_with_macro(
+                    self.db,
+                    ResolveMode::Other,
+                    directive.module_id,
+                    &path,
+                    BuiltinShadowMode::Module,
+                );
+                resolved_res.resolved_def.take_macros()
+            }) {
                 resolved.push((directive.module_id, call_id));
                 res = ReachedFixedPoint::No;
                 return false;
@@ -532,12 +538,11 @@ where
 
             true
         });
-        attribute_macros.retain(|(module_id, ast_id, path)| {
-            let resolved_res = self.resolve_attribute_macro(path);
-
-            if let Some(def) = resolved_res {
-                let call_id = def.as_call_id(self.db, MacroCallKind::Attr(*ast_id));
-                resolved.push((*module_id, call_id));
+        attribute_macros.retain(|directive| {
+            if let Some(call_id) =
+                directive.ast_id.as_call_id(self.db, |path| self.resolve_attribute_macro(&path))
+            {
+                resolved.push((directive.module_id, call_id));
                 res = ReachedFixedPoint::No;
                 return false;
             }
@@ -833,20 +838,22 @@ where
                 };
                 let path = ModPath::from_tt_ident(ident);
 
-                let ast_id = AstId::new(self.file_id, def.kind.ast_id());
-                self.def_collector.unexpanded_attribute_macros.push((self.module_id, ast_id, path));
+                let ast_id = AstIdWithPath::new(self.file_id, def.kind.ast_id(), path);
+                self.def_collector
+                    .unexpanded_attribute_macros
+                    .push(DeriveDirective { module_id: self.module_id, ast_id });
             }
         }
     }
 
     fn collect_macro(&mut self, mac: &raw::MacroData) {
-        let ast_id = AstId::new(self.file_id, mac.ast_id);
+        let mut ast_id = AstIdWithPath::new(self.file_id, mac.ast_id, mac.path.clone());
 
         // Case 0: builtin macros
         if mac.builtin {
             if let Some(name) = &mac.name {
                 let krate = self.def_collector.def_map.krate;
-                if let Some(macro_id) = find_builtin_macro(name, krate, ast_id) {
+                if let Some(macro_id) = find_builtin_macro(name, krate, ast_id.ast_id) {
                     self.def_collector.define_macro(
                         self.module_id,
                         name.clone(),
@@ -862,7 +869,7 @@ where
         if is_macro_rules(&mac.path) {
             if let Some(name) = &mac.name {
                 let macro_id = MacroDefId {
-                    ast_id: Some(ast_id),
+                    ast_id: Some(ast_id.ast_id),
                     krate: Some(self.def_collector.def_map.krate),
                     kind: MacroDefKind::Declarative,
                 };
@@ -872,15 +879,13 @@ where
         }
 
         // Case 2: try to resolve in legacy scope and expand macro_rules
-        if let Some(macro_def) = mac.path.as_ident().and_then(|name| {
-            self.def_collector.def_map[self.module_id].scope.get_legacy_macro(&name)
+        if let Some(macro_call_id) = ast_id.as_call_id(self.def_collector.db, |path| {
+            path.as_ident().and_then(|name| {
+                self.def_collector.def_map[self.module_id].scope.get_legacy_macro(&name)
+            })
         }) {
-            let macro_call_id =
-                macro_def.as_call_id(self.def_collector.db, MacroCallKind::FnLike(ast_id));
-
             self.def_collector.unexpanded_macros.push(MacroDirective {
                 module_id: self.module_id,
-                path: mac.path.clone(),
                 ast_id,
                 legacy: Some(macro_call_id),
             });
@@ -890,14 +895,12 @@ where
 
         // Case 3: resolve in module scope, expand during name resolution.
         // We rewrite simple path `macro_name` to `self::macro_name` to force resolve in module scope only.
-        let mut path = mac.path.clone();
-        if path.is_ident() {
-            path.kind = PathKind::Super(0);
+        if ast_id.path.is_ident() {
+            ast_id.path.kind = PathKind::Super(0);
         }
 
         self.def_collector.unexpanded_macros.push(MacroDirective {
             module_id: self.module_id,
-            path,
             ast_id,
             legacy: None,
         });
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_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 7cf3b59a7..9506f2e1c 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -323,11 +323,18 @@ impl<T: Clone> InFile<&T> {
     }
 }
 
+impl<T> InFile<Option<T>> {
+    pub fn transpose(self) -> Option<InFile<T>> {
+        let value = self.value?;
+        Some(InFile::new(self.file_id, value))
+    }
+}
+
 impl InFile<SyntaxNode> {
-    pub fn ancestors_with_macros<'a>(
+    pub fn ancestors_with_macros(
         self,
-        db: &'a impl crate::db::AstDatabase,
-    ) -> impl Iterator<Item = InFile<SyntaxNode>> + 'a {
+        db: &impl crate::db::AstDatabase,
+    ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
         std::iter::successors(Some(self), move |node| match node.value.parent() {
             Some(parent) => Some(node.with_value(parent)),
             None => {
@@ -338,6 +345,15 @@ impl InFile<SyntaxNode> {
     }
 }
 
+impl InFile<SyntaxToken> {
+    pub fn ancestors_with_macros(
+        self,
+        db: &impl crate::db::AstDatabase,
+    ) -> impl Iterator<Item = InFile<SyntaxNode>> + '_ {
+        self.map(|it| it.parent()).ancestors_with_macros(db)
+    }
+}
+
 impl<N: AstNode> InFile<N> {
     pub fn descendants<T: AstNode>(self) -> impl Iterator<Item = InFile<T>> {
         self.value.syntax().descendants().filter_map(T::cast).map(move |n| self.with_value(n))
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/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 3c9c02d03..39d8bc0ca 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -165,12 +165,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Expr::Match { expr, arms } => {
                 let input_ty = self.infer_expr(*expr, &Expectation::none());
 
-                let mut result_ty = self.table.new_maybe_never_type_var();
+                let mut result_ty = if arms.len() == 0 {
+                    Ty::simple(TypeCtor::Never)
+                } else {
+                    self.table.new_type_var()
+                };
 
                 for arm in arms {
-                    for &pat in &arm.pats {
-                        let _pat_ty = self.infer_pat(pat, &input_ty, BindingMode::default());
-                    }
+                    let _pat_ty = self.infer_pat(arm.pat, &input_ty, BindingMode::default());
                     if let Some(guard_expr) = arm.guard {
                         self.infer_expr(
                             guard_expr,
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index e7283f24c..a5dfdf6c4 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -82,6 +82,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
         let is_non_ref_pat = match &body[pat] {
             Pat::Tuple(..)
+            | Pat::Or(..)
             | Pat::TupleStruct { .. }
             | Pat::Record { .. }
             | Pat::Range { .. }
@@ -126,6 +127,17 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
                 Ty::apply(TypeCtor::Tuple { cardinality: args.len() as u16 }, Substs(inner_tys))
             }
+            Pat::Or(ref pats) => {
+                if let Some((first_pat, rest)) = pats.split_first() {
+                    let ty = self.infer_pat(*first_pat, expected, default_bm);
+                    for pat in rest {
+                        self.infer_pat(*pat, expected, default_bm);
+                    }
+                    ty
+                } else {
+                    Ty::Unknown
+                }
+            }
             Pat::Ref { pat, mutability } => {
                 let expectation = match expected.as_reference() {
                     Some((inner_ty, exp_mut)) => {
diff --git a/crates/ra_hir_ty/src/infer/unify.rs b/crates/ra_hir_ty/src/infer/unify.rs
index fe05642ae..1dc842f40 100644
--- a/crates/ra_hir_ty/src/infer/unify.rs
+++ b/crates/ra_hir_ty/src/infer/unify.rs
@@ -249,6 +249,8 @@ impl InferenceTable {
         match (ty1, ty2) {
             (Ty::Unknown, _) | (_, Ty::Unknown) => true,
 
+            (Ty::Placeholder(p1), Ty::Placeholder(p2)) if *p1 == *p2 => true,
+
             (Ty::Infer(InferTy::TypeVar(tv1)), Ty::Infer(InferTy::TypeVar(tv2)))
             | (Ty::Infer(InferTy::IntVar(tv1)), Ty::Infer(InferTy::IntVar(tv2)))
             | (Ty::Infer(InferTy::FloatVar(tv1)), Ty::Infer(InferTy::FloatVar(tv2)))
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/coercion.rs b/crates/ra_hir_ty/src/tests/coercion.rs
index fc5ef36a5..42330b269 100644
--- a/crates/ra_hir_ty/src/tests/coercion.rs
+++ b/crates/ra_hir_ty/src/tests/coercion.rs
@@ -526,3 +526,25 @@ fn test() {
     "###
     );
 }
+
+#[test]
+fn coerce_placeholder_ref() {
+    // placeholders should unify, even behind references
+    assert_snapshot!(
+        infer_with_mismatches(r#"
+struct S<T> { t: T }
+impl<TT> S<TT> {
+    fn get(&self) -> &TT {
+        &self.t
+    }
+}
+"#, true),
+        @r###"
+    [51; 55) 'self': &S<TT>
+    [64; 87) '{     ...     }': &TT
+    [74; 81) '&self.t': &TT
+    [75; 79) 'self': &S<TT>
+    [75; 81) 'self.t': TT
+    "###
+    );
+}
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/never_type.rs b/crates/ra_hir_ty/src/tests/never_type.rs
index c202f545a..a77209480 100644
--- a/crates/ra_hir_ty/src/tests/never_type.rs
+++ b/crates/ra_hir_ty/src/tests/never_type.rs
@@ -101,6 +101,7 @@ fn test() {
     );
     assert_eq!(t, "Option<i32>");
 }
+
 #[test]
 fn never_type_can_be_reinferred3() {
     let t = type_at(
@@ -138,6 +139,22 @@ fn test(a: Void) {
 }
 
 #[test]
+fn match_unknown_arm() {
+    let t = type_at(
+        r#"
+//- /main.rs
+fn test(a: Option) {
+    let t = match 0 {
+        _ => unknown,
+    };
+    t<|>;
+}
+"#,
+    );
+    assert_eq!(t, "{unknown}");
+}
+
+#[test]
 fn if_never() {
     let t = 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.rs b/crates/ra_hir_ty/src/traits.rs
index 88af61e87..ff8e75b48 100644
--- a/crates/ra_hir_ty/src/traits.rs
+++ b/crates/ra_hir_ty/src/traits.rs
@@ -60,6 +60,9 @@ impl TraitSolver {
                     context.0.db.check_canceled();
                     let remaining = fuel.get();
                     fuel.set(remaining - 1);
+                    if remaining == 0 {
+                        log::debug!("fuel exhausted");
+                    }
                     remaining > 0
                 })
             }
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_ide/src/goto_type_definition.rs b/crates/ra_ide/src/goto_type_definition.rs
index 11ad6d137..69940fc36 100644
--- a/crates/ra_ide/src/goto_type_definition.rs
+++ b/crates/ra_ide/src/goto_type_definition.rs
@@ -16,24 +16,16 @@ pub(crate) fn goto_type_definition(
     let token = pick_best(file.token_at_offset(position.offset))?;
     let token = descend_into_macros(db, position.file_id, token);
 
-    let node = token.value.ancestors().find_map(|token| {
-        token
-            .ancestors()
-            .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())
-    })?;
+    let node = token
+        .value
+        .ancestors()
+        .find(|n| ast::Expr::cast(n.clone()).is_some() || ast::Pat::cast(n.clone()).is_some())?;
 
     let analyzer = hir::SourceAnalyzer::new(db, token.with_value(&node), None);
 
-    let ty: hir::Type = if let Some(ty) =
-        ast::Expr::cast(node.clone()).and_then(|e| analyzer.type_of(db, &e))
-    {
-        ty
-    } else if let Some(ty) = ast::Pat::cast(node.clone()).and_then(|p| analyzer.type_of_pat(db, &p))
-    {
-        ty
-    } else {
-        return None;
-    };
+    let ty: hir::Type = ast::Expr::cast(node.clone())
+        .and_then(|e| analyzer.type_of(db, &e))
+        .or_else(|| ast::Pat::cast(node.clone()).and_then(|p| analyzer.type_of_pat(db, &p)))?;
 
     let adt_def = ty.autoderef(db).find_map(|ty| ty.as_adt())?;
 
diff --git a/crates/ra_ide/src/inlay_hints.rs b/crates/ra_ide/src/inlay_hints.rs
index 6b0d3d996..2ae97e65f 100644
--- a/crates/ra_ide/src/inlay_hints.rs
+++ b/crates/ra_ide/src/inlay_hints.rs
@@ -80,8 +80,7 @@ fn get_inlay_hints(
             },
             ast::MatchArmList(it) => {
                 it.arms()
-                    .map(|match_arm| match_arm.pats())
-                    .flatten()
+                    .filter_map(|match_arm| match_arm.pat())
                     .for_each(|root_pat| get_pat_type_hints(acc, db, &analyzer, root_pat, true, max_inlay_hint_length));
             },
             ast::CallExpr(it) => {
@@ -202,6 +201,7 @@ fn get_leaf_pats(root_pat: ast::Pat) -> Vec<ast::Pat> {
                 Some(pat) => pats_to_process.push_back(pat),
                 _ => leaf_pats.push(maybe_leaf_pat),
             },
+            ast::Pat::OrPat(ref_pat) => pats_to_process.extend(ref_pat.pats()),
             ast::Pat::TuplePat(tuple_pat) => pats_to_process.extend(tuple_pat.args()),
             ast::Pat::RecordPat(record_pat) => {
                 if let Some(pat_list) = record_pat.record_field_pat_list() {
@@ -222,6 +222,7 @@ fn get_leaf_pats(root_pat: ast::Pat) -> Vec<ast::Pat> {
             ast::Pat::TupleStructPat(tuple_struct_pat) => {
                 pats_to_process.extend(tuple_struct_pat.args())
             }
+            ast::Pat::ParenPat(inner_pat) => pats_to_process.extend(inner_pat.pat()),
             ast::Pat::RefPat(ref_pat) => pats_to_process.extend(ref_pat.pat()),
             _ => (),
         }
diff --git a/crates/ra_ide/src/join_lines.rs b/crates/ra_ide/src/join_lines.rs
index 7deeb3494..01fb32b3d 100644
--- a/crates/ra_ide/src/join_lines.rs
+++ b/crates/ra_ide/src/join_lines.rs
@@ -60,36 +60,15 @@ fn remove_newline(edit: &mut TextEditBuilder, token: &SyntaxToken, offset: TextU
         return;
     }
 
-    // Special case that turns something like:
-    //
-    // ```
-    // my_function({<|>
-    //    <some-expr>
-    // })
-    // ```
-    //
-    // into `my_function(<some-expr>)`
-    if join_single_expr_block(edit, token).is_some() {
-        return;
-    }
-    // ditto for
-    //
-    // ```
-    // use foo::{<|>
-    //    bar
-    // };
-    // ```
-    if join_single_use_tree(edit, token).is_some() {
-        return;
-    }
-
     // The node is between two other nodes
     let prev = token.prev_sibling_or_token().unwrap();
     let next = token.next_sibling_or_token().unwrap();
     if is_trailing_comma(prev.kind(), next.kind()) {
         // Removes: trailing comma, newline (incl. surrounding whitespace)
         edit.delete(TextRange::from_to(prev.text_range().start(), token.text_range().end()));
-    } else if prev.kind() == T![,] && next.kind() == T!['}'] {
+        return;
+    }
+    if prev.kind() == T![,] && next.kind() == T!['}'] {
         // Removes: comma, newline (incl. surrounding whitespace)
         let space = if let Some(left) = prev.prev_sibling_or_token() {
             compute_ws(left.kind(), next.kind())
@@ -100,7 +79,10 @@ fn remove_newline(edit: &mut TextEditBuilder, token: &SyntaxToken, offset: TextU
             TextRange::from_to(prev.text_range().start(), token.text_range().end()),
             space.to_string(),
         );
-    } else if let (Some(_), Some(next)) = (
+        return;
+    }
+
+    if let (Some(_), Some(next)) = (
         prev.as_token().cloned().and_then(ast::Comment::cast),
         next.as_token().cloned().and_then(ast::Comment::cast),
     ) {
@@ -109,10 +91,34 @@ fn remove_newline(edit: &mut TextEditBuilder, token: &SyntaxToken, offset: TextU
             token.text_range().start(),
             next.syntax().text_range().start() + TextUnit::of_str(next.prefix()),
         ));
-    } else {
-        // Remove newline but add a computed amount of whitespace characters
-        edit.replace(token.text_range(), compute_ws(prev.kind(), next.kind()).to_string());
+        return;
+    }
+
+    // Special case that turns something like:
+    //
+    // ```
+    // my_function({<|>
+    //    <some-expr>
+    // })
+    // ```
+    //
+    // into `my_function(<some-expr>)`
+    if join_single_expr_block(edit, token).is_some() {
+        return;
     }
+    // ditto for
+    //
+    // ```
+    // use foo::{<|>
+    //    bar
+    // };
+    // ```
+    if join_single_use_tree(edit, token).is_some() {
+        return;
+    }
+
+    // Remove newline but add a computed amount of whitespace characters
+    edit.replace(token.text_range(), compute_ws(prev.kind(), next.kind()).to_string());
 }
 
 fn has_comma_after(node: &SyntaxNode) -> bool {
@@ -608,4 +614,27 @@ pub fn handle_find_matching_brace() {
 }",
         );
     }
+
+    #[test]
+    fn test_join_lines_commented_block() {
+        check_join_lines(
+            r"
+fn main() {
+    let _ = {
+        // <|>foo
+        // bar
+        92
+    };
+}
+        ",
+            r"
+fn main() {
+    let _ = {
+        // <|>foo bar
+        92
+    };
+}
+        ",
+        )
+    }
 }
diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 689921f3f..9d66c365b 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -71,7 +71,7 @@ pub use crate::{
     references::{
         Declaration, Reference, ReferenceAccess, ReferenceKind, ReferenceSearchResult, SearchScope,
     },
-    runnables::{Runnable, RunnableKind},
+    runnables::{Runnable, RunnableKind, TestId},
     source_change::{FileSystemEdit, SourceChange, SourceFileEdit},
     syntax_highlighting::HighlightedRange,
 };
diff --git a/crates/ra_ide/src/references.rs b/crates/ra_ide/src/references.rs
index a6320bd2f..de924fad2 100644
--- a/crates/ra_ide/src/references.rs
+++ b/crates/ra_ide/src/references.rs
@@ -13,6 +13,7 @@ mod classify;
 mod rename;
 mod search_scope;
 
+use crate::expand::descend_into_macros_with_analyzer;
 use hir::{InFile, SourceBinder};
 use once_cell::unsync::Lazy;
 use ra_db::{SourceDatabase, SourceDatabaseExt};
@@ -192,39 +193,62 @@ fn process_definition(
 
         let parse = Lazy::new(|| SourceFile::parse(&text));
         let mut sb = Lazy::new(|| SourceBinder::new(db));
+        let mut analyzer = None;
 
         for (idx, _) in text.match_indices(pat) {
             let offset = TextUnit::from_usize(idx);
 
-            if let Some(name_ref) =
+            let (name_ref, range) = if let Some(name_ref) =
                 find_node_at_offset::<ast::NameRef>(parse.tree().syntax(), offset)
             {
                 let range = name_ref.syntax().text_range();
-                if let Some(search_range) = search_range {
-                    if !range.is_subrange(&search_range) {
-                        continue;
-                    }
+                (InFile::new(file_id.into(), name_ref), range)
+            } else {
+                // Handle macro token cases
+                let t = match parse.tree().syntax().token_at_offset(offset) {
+                    TokenAtOffset::None => continue,
+                    TokenAtOffset::Single(t) => t,
+                    TokenAtOffset::Between(_, t) => t,
+                };
+                let range = t.text_range();
+                let analyzer = analyzer.get_or_insert_with(|| {
+                    sb.analyze(InFile::new(file_id.into(), parse.tree().syntax()), None)
+                });
+                let expanded = descend_into_macros_with_analyzer(
+                    db,
+                    &analyzer,
+                    InFile::new(file_id.into(), t),
+                );
+                if let Some(token) = ast::NameRef::cast(expanded.value.parent()) {
+                    (expanded.with_value(token), range)
+                } else {
+                    continue;
                 }
-                // FIXME: reuse sb
-                // See https://github.com/rust-lang/rust/pull/68198#issuecomment-574269098
-
-                if let Some(d) = classify_name_ref(&mut sb, InFile::new(file_id.into(), &name_ref))
-                {
-                    if d == def {
-                        let kind = if is_record_lit_name_ref(&name_ref)
-                            || is_call_expr_name_ref(&name_ref)
-                        {
-                            ReferenceKind::StructLiteral
-                        } else {
-                            ReferenceKind::Other
-                        };
-
-                        refs.push(Reference {
-                            file_range: FileRange { file_id, range },
-                            kind,
-                            access: reference_access(&d.kind, &name_ref),
-                        });
-                    }
+            };
+
+            if let Some(search_range) = search_range {
+                if !range.is_subrange(&search_range) {
+                    continue;
+                }
+            }
+            // FIXME: reuse sb
+            // See https://github.com/rust-lang/rust/pull/68198#issuecomment-574269098
+
+            if let Some(d) = classify_name_ref(&mut sb, name_ref.as_ref()) {
+                if d == def {
+                    let kind = if is_record_lit_name_ref(&name_ref.value)
+                        || is_call_expr_name_ref(&name_ref.value)
+                    {
+                        ReferenceKind::StructLiteral
+                    } else {
+                        ReferenceKind::Other
+                    };
+
+                    refs.push(Reference {
+                        file_range: FileRange { file_id, range },
+                        kind,
+                        access: reference_access(&d.kind, &name_ref.value),
+                    });
                 }
             }
         }
diff --git a/crates/ra_ide/src/references/rename.rs b/crates/ra_ide/src/references/rename.rs
index 08e77c01f..c46b78cb6 100644
--- a/crates/ra_ide/src/references/rename.rs
+++ b/crates/ra_ide/src/references/rename.rs
@@ -211,6 +211,25 @@ mod tests {
     }
 
     #[test]
+    fn test_rename_for_macro_args() {
+        test_rename(
+            r#"
+    macro_rules! foo {($i:ident) => {$i} }
+    fn main() {
+        let a<|> = "test";
+        foo!(a);
+    }"#,
+            "b",
+            r#"
+    macro_rules! foo {($i:ident) => {$i} }
+    fn main() {
+        let b = "test";
+        foo!(b);
+    }"#,
+        );
+    }
+
+    #[test]
     fn test_rename_for_param_inside() {
         test_rename(
             r#"
diff --git a/crates/ra_ide/src/runnables.rs b/crates/ra_ide/src/runnables.rs
index b6b0c70f9..be2a67d0a 100644
--- a/crates/ra_ide/src/runnables.rs
+++ b/crates/ra_ide/src/runnables.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-use hir::InFile;
+use hir::{InFile, SourceBinder};
 use itertools::Itertools;
 use ra_db::SourceDatabase;
 use ra_ide_db::RootDatabase;
@@ -10,6 +10,7 @@ use ra_syntax::{
 };
 
 use crate::FileId;
+use std::fmt::Display;
 
 #[derive(Debug)]
 pub struct Runnable {
@@ -18,38 +19,84 @@ pub struct Runnable {
 }
 
 #[derive(Debug)]
+pub enum TestId {
+    Name(String),
+    Path(String),
+}
+
+impl Display for TestId {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            TestId::Name(name) => write!(f, "{}", name),
+            TestId::Path(path) => write!(f, "{}", path),
+        }
+    }
+}
+
+#[derive(Debug)]
 pub enum RunnableKind {
-    Test { name: String },
+    Test { test_id: TestId },
     TestMod { path: String },
-    Bench { name: String },
+    Bench { test_id: TestId },
     Bin,
 }
 
 pub(crate) fn runnables(db: &RootDatabase, file_id: FileId) -> Vec<Runnable> {
     let parse = db.parse(file_id);
-    parse.tree().syntax().descendants().filter_map(|i| runnable(db, file_id, i)).collect()
+    let mut sb = SourceBinder::new(db);
+    parse.tree().syntax().descendants().filter_map(|i| runnable(db, &mut sb, file_id, i)).collect()
 }
 
-fn runnable(db: &RootDatabase, file_id: FileId, item: SyntaxNode) -> Option<Runnable> {
+fn runnable(
+    db: &RootDatabase,
+    source_binder: &mut SourceBinder<RootDatabase>,
+    file_id: FileId,
+    item: SyntaxNode,
+) -> Option<Runnable> {
     match_ast! {
         match item {
-            ast::FnDef(it) => { runnable_fn(it) },
-            ast::Module(it) => { runnable_mod(db, file_id, it) },
+            ast::FnDef(it) => { runnable_fn(db, source_binder, file_id, it) },
+            ast::Module(it) => { runnable_mod(db, source_binder, file_id, it) },
             _ => { None },
         }
     }
 }
 
-fn runnable_fn(fn_def: ast::FnDef) -> Option<Runnable> {
-    let name = fn_def.name()?.text().clone();
-    let kind = if name == "main" {
+fn runnable_fn(
+    db: &RootDatabase,
+    source_binder: &mut SourceBinder<RootDatabase>,
+    file_id: FileId,
+    fn_def: ast::FnDef,
+) -> Option<Runnable> {
+    let name_string = fn_def.name()?.text().to_string();
+
+    let kind = if name_string == "main" {
         RunnableKind::Bin
-    } else if has_test_related_attribute(&fn_def) {
-        RunnableKind::Test { name: name.to_string() }
-    } else if fn_def.has_atom_attr("bench") {
-        RunnableKind::Bench { name: name.to_string() }
     } else {
-        return None;
+        let test_id = if let Some(module) = source_binder
+            .to_def(InFile::new(file_id.into(), fn_def.clone()))
+            .map(|def| def.module(db))
+        {
+            let path = module
+                .path_to_root(db)
+                .into_iter()
+                .rev()
+                .filter_map(|it| it.name(db))
+                .map(|name| name.to_string())
+                .chain(std::iter::once(name_string))
+                .join("::");
+            TestId::Path(path)
+        } else {
+            TestId::Name(name_string)
+        };
+
+        if has_test_related_attribute(&fn_def) {
+            RunnableKind::Test { test_id }
+        } else if fn_def.has_atom_attr("bench") {
+            RunnableKind::Bench { test_id }
+        } else {
+            return None;
+        }
     };
     Some(Runnable { range: fn_def.syntax().text_range(), kind })
 }
@@ -68,7 +115,12 @@ fn has_test_related_attribute(fn_def: &ast::FnDef) -> bool {
         .any(|attribute_text| attribute_text.contains("test"))
 }
 
-fn runnable_mod(db: &RootDatabase, file_id: FileId, module: ast::Module) -> Option<Runnable> {
+fn runnable_mod(
+    db: &RootDatabase,
+    source_binder: &mut SourceBinder<RootDatabase>,
+    file_id: FileId,
+    module: ast::Module,
+) -> Option<Runnable> {
     let has_test_function = module
         .item_list()?
         .items()
@@ -76,13 +128,12 @@ fn runnable_mod(db: &RootDatabase, file_id: FileId, module: ast::Module) -> Opti
             ast::ModuleItem::FnDef(it) => Some(it),
             _ => None,
         })
-        .any(|f| f.has_atom_attr("test"));
+        .any(|f| has_test_related_attribute(&f));
     if !has_test_function {
         return None;
     }
     let range = module.syntax().text_range();
-    let mut sb = hir::SourceBinder::new(db);
-    let module = sb.to_def(InFile::new(file_id.into(), module))?;
+    let module = source_binder.to_def(InFile::new(file_id.into(), module))?;
 
     let path = module.path_to_root(db).into_iter().rev().filter_map(|it| it.name(db)).join("::");
     Some(Runnable { range, kind: RunnableKind::TestMod { path } })
@@ -121,13 +172,17 @@ mod tests {
             Runnable {
                 range: [22; 46),
                 kind: Test {
-                    name: "test_foo",
+                    test_id: Path(
+                        "test_foo",
+                    ),
                 },
             },
             Runnable {
                 range: [47; 81),
                 kind: Test {
-                    name: "test_foo",
+                    test_id: Path(
+                        "test_foo",
+                    ),
                 },
             },
         ]
@@ -160,7 +215,9 @@ mod tests {
             Runnable {
                 range: [28; 57),
                 kind: Test {
-                    name: "test_foo1",
+                    test_id: Path(
+                        "test_mod::test_foo1",
+                    ),
                 },
             },
         ]
@@ -195,7 +252,9 @@ mod tests {
             Runnable {
                 range: [46; 79),
                 kind: Test {
-                    name: "test_foo1",
+                    test_id: Path(
+                        "foo::test_mod::test_foo1",
+                    ),
                 },
             },
         ]
@@ -232,7 +291,9 @@ mod tests {
             Runnable {
                 range: [68; 105),
                 kind: Test {
-                    name: "test_foo1",
+                    test_id: Path(
+                        "foo::bar::test_mod::test_foo1",
+                    ),
                 },
             },
         ]
diff --git a/crates/ra_ide/src/snapshots/highlighting.html b/crates/ra_ide/src/snapshots/highlighting.html
index 1cc55e78b..a02dbaf2f 100644
--- a/crates/ra_ide/src/snapshots/highlighting.html
+++ b/crates/ra_ide/src/snapshots/highlighting.html
@@ -16,6 +16,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .literal            { color: #BFEBBF; }
 .literal\.numeric  { color: #6A8759; }
 .macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
 .variable\.mut     { color: #DCDCCC; text-decoration: underline; }
 
diff --git a/crates/ra_ide/src/snapshots/rainbow_highlighting.html b/crates/ra_ide/src/snapshots/rainbow_highlighting.html
index 918fd4b97..95f038f00 100644
--- a/crates/ra_ide/src/snapshots/rainbow_highlighting.html
+++ b/crates/ra_ide/src/snapshots/rainbow_highlighting.html
@@ -16,6 +16,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .literal            { color: #BFEBBF; }
 .literal\.numeric  { color: #6A8759; }
 .macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
 .variable\.mut     { color: #DCDCCC; text-decoration: underline; }
 
diff --git a/crates/ra_ide/src/syntax_highlighting.rs b/crates/ra_ide/src/syntax_highlighting.rs
index 174e13595..20c414ca1 100644
--- a/crates/ra_ide/src/syntax_highlighting.rs
+++ b/crates/ra_ide/src/syntax_highlighting.rs
@@ -365,6 +365,7 @@ pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padd
 .literal            { color: #BFEBBF; }
 .literal\\.numeric  { color: #6A8759; }
 .macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
 .variable           { color: #DCDCCC; }
 .variable\\.mut     { color: #DCDCCC; text-decoration: underline; }
 
diff --git a/crates/ra_ide_db/Cargo.toml b/crates/ra_ide_db/Cargo.toml
index 716e88bc1..495fffb5a 100644
--- a/crates/ra_ide_db/Cargo.toml
+++ b/crates/ra_ide_db/Cargo.toml
@@ -22,7 +22,6 @@ fst = { version = "0.3.1", default-features = false }
 rustc-hash = "1.0"
 unicase = "2.2.0"
 superslice = "1.0.0"
-rand = { version = "0.7.0", features = ["small_rng"] }
 once_cell = "1.2.0"
 
 ra_syntax = { path = "../ra_syntax" }
diff --git a/crates/ra_lsp_server/src/cargo_target_spec.rs b/crates/ra_lsp_server/src/cargo_target_spec.rs
index 594caffe2..5fd1e7b6b 100644
--- a/crates/ra_lsp_server/src/cargo_target_spec.rs
+++ b/crates/ra_lsp_server/src/cargo_target_spec.rs
@@ -1,6 +1,6 @@
 //! FIXME: write short doc here
 
-use ra_ide::{FileId, RunnableKind};
+use ra_ide::{FileId, RunnableKind, TestId};
 use ra_project_model::{self, ProjectWorkspace, TargetKind};
 
 use crate::{world::WorldSnapshot, Result};
@@ -13,13 +13,16 @@ pub(crate) fn runnable_args(
     let spec = CargoTargetSpec::for_file(world, file_id)?;
     let mut res = Vec::new();
     match kind {
-        RunnableKind::Test { name } => {
+        RunnableKind::Test { test_id } => {
             res.push("test".to_string());
             if let Some(spec) = spec {
                 spec.push_to(&mut res);
             }
             res.push("--".to_string());
-            res.push(name.to_string());
+            res.push(test_id.to_string());
+            if let TestId::Path(_) = test_id {
+                res.push("--exact".to_string());
+            }
             res.push("--nocapture".to_string());
         }
         RunnableKind::TestMod { path } => {
@@ -31,13 +34,16 @@ pub(crate) fn runnable_args(
             res.push(path.to_string());
             res.push("--nocapture".to_string());
         }
-        RunnableKind::Bench { name } => {
+        RunnableKind::Bench { test_id } => {
             res.push("bench".to_string());
             if let Some(spec) = spec {
                 spec.push_to(&mut res);
             }
             res.push("--".to_string());
-            res.push(name.to_string());
+            res.push(test_id.to_string());
+            if let TestId::Path(_) = test_id {
+                res.push("--exact".to_string());
+            }
             res.push("--nocapture".to_string());
         }
         RunnableKind::Bin => {
diff --git a/crates/ra_lsp_server/src/config.rs b/crates/ra_lsp_server/src/config.rs
index 2d7948d74..3314269ec 100644
--- a/crates/ra_lsp_server/src/config.rs
+++ b/crates/ra_lsp_server/src/config.rs
@@ -44,6 +44,8 @@ pub struct ServerConfig {
     /// Fine grained feature flags to disable specific features.
     pub feature_flags: FxHashMap<String, bool>,
 
+    pub rustfmt_args: Vec<String>,
+
     /// Cargo feature configurations.
     pub cargo_features: CargoFeatures,
 }
@@ -63,6 +65,7 @@ impl Default for ServerConfig {
             with_sysroot: true,
             feature_flags: FxHashMap::default(),
             cargo_features: Default::default(),
+            rustfmt_args: Vec::new(),
         }
     }
 }
diff --git a/crates/ra_lsp_server/src/lib.rs b/crates/ra_lsp_server/src/lib.rs
index 1208c1343..a3464a5a3 100644
--- a/crates/ra_lsp_server/src/lib.rs
+++ b/crates/ra_lsp_server/src/lib.rs
@@ -31,6 +31,8 @@ mod config;
 mod world;
 mod diagnostics;
 
+use serde::de::DeserializeOwned;
+
 pub type Result<T> = std::result::Result<T, Box<dyn std::error::Error + Send + Sync>>;
 pub use crate::{
     caps::server_capabilities,
@@ -38,3 +40,9 @@ pub use crate::{
     main_loop::LspError,
     main_loop::{main_loop, show_message},
 };
+
+pub fn from_json<T: DeserializeOwned>(what: &'static str, json: serde_json::Value) -> Result<T> {
+    let res = T::deserialize(&json)
+        .map_err(|e| format!("Failed to deserialize {}: {}; {}", what, e, json))?;
+    Ok(res)
+}
diff --git a/crates/ra_lsp_server/src/main.rs b/crates/ra_lsp_server/src/main.rs
index 3879eeff2..ed2eaabd4 100644
--- a/crates/ra_lsp_server/src/main.rs
+++ b/crates/ra_lsp_server/src/main.rs
@@ -1,7 +1,7 @@
 //! `ra_lsp_server` binary
 
 use lsp_server::Connection;
-use ra_lsp_server::{show_message, Result, ServerConfig};
+use ra_lsp_server::{from_json, show_message, Result, ServerConfig};
 use ra_prof;
 
 fn main() -> Result<()> {
@@ -15,13 +15,8 @@ fn main() -> Result<()> {
 
 fn setup_logging() -> Result<()> {
     std::env::set_var("RUST_BACKTRACE", "short");
-
     env_logger::try_init()?;
-
-    ra_prof::set_filter(match std::env::var("RA_PROFILE") {
-        Ok(spec) => ra_prof::Filter::from_spec(&spec),
-        Err(_) => ra_prof::Filter::disabled(),
-    });
+    ra_prof::init();
     Ok(())
 }
 
@@ -45,7 +40,8 @@ fn run_server() -> Result<()> {
     let server_capabilities = serde_json::to_value(ra_lsp_server::server_capabilities()).unwrap();
 
     let initialize_params = connection.initialize(server_capabilities)?;
-    let initialize_params: lsp_types::InitializeParams = serde_json::from_value(initialize_params)?;
+    let initialize_params =
+        from_json::<lsp_types::InitializeParams>("InitializeParams", initialize_params)?;
 
     if let Some(client_info) = initialize_params.client_info {
         log::info!("Client '{}' {}", client_info.name, client_info.version.unwrap_or_default());
@@ -62,17 +58,13 @@ fn run_server() -> Result<()> {
         .filter(|workspaces| !workspaces.is_empty())
         .unwrap_or_else(|| vec![root]);
 
-    let server_config: ServerConfig = initialize_params
+    let server_config = initialize_params
         .initialization_options
         .and_then(|v| {
-            serde_json::from_value(v)
+            from_json::<ServerConfig>("config", v)
                 .map_err(|e| {
-                    log::error!("failed to deserialize config: {}", e);
-                    show_message(
-                        lsp_types::MessageType::Error,
-                        format!("failed to deserialize config: {}", e),
-                        &connection.sender,
-                    );
+                    log::error!("{}", e);
+                    show_message(lsp_types::MessageType::Error, e.to_string(), &connection.sender);
                 })
                 .ok()
         })
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index ceff82fda..1e70cea13 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -178,6 +178,7 @@ pub fn main_loop(
                     command: config.cargo_watch_command,
                     all_targets: config.cargo_watch_all_targets,
                 },
+                rustfmt_args: config.rustfmt_args,
             }
         };
 
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 65e8bc856..3893430c0 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -35,6 +35,7 @@ use crate::{
         TryConvWithToVec,
     },
     diagnostics::DiagnosticTask,
+    from_json,
     req::{self, Decoration, InlayHint, InlayHintsParams, InlayKind},
     world::WorldSnapshot,
     LspError, Result,
@@ -589,6 +590,7 @@ pub fn handle_formatting(
     let end_position = TextUnit::of_str(&file).conv_with(&file_line_index);
 
     let mut rustfmt = process::Command::new("rustfmt");
+    rustfmt.args(&world.options.rustfmt_args);
     if let Some(&crate_id) = crate_ids.first() {
         // Assume all crates are in the same edition
         let edition = world.analysis().crate_edition(crate_id)?;
@@ -757,7 +759,7 @@ 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",
         }
@@ -811,7 +813,7 @@ enum CodeLensResolveData {
 pub fn handle_code_lens_resolve(world: WorldSnapshot, code_lens: CodeLens) -> Result<CodeLens> {
     let _p = profile("handle_code_lens_resolve");
     let data = code_lens.data.unwrap();
-    let resolve = serde_json::from_value(data)?;
+    let resolve = from_json::<Option<CodeLensResolveData>>("CodeLensResolveData", data)?;
     match resolve {
         Some(CodeLensResolveData::Impls(lens_params)) => {
             let locations: Vec<Location> =
@@ -917,9 +919,9 @@ fn to_lsp_runnable(
     let args = runnable_args(world, file_id, &runnable.kind)?;
     let line_index = world.analysis().file_line_index(file_id)?;
     let label = match &runnable.kind {
-        RunnableKind::Test { name } => format!("test {}", name),
+        RunnableKind::Test { test_id } => format!("test {}", test_id),
         RunnableKind::TestMod { path } => format!("test-mod {}", path),
-        RunnableKind::Bench { name } => format!("bench {}", name),
+        RunnableKind::Bench { test_id } => format!("bench {}", test_id),
         RunnableKind::Bin => "run binary".to_string(),
     };
     Ok(req::Runnable {
diff --git a/crates/ra_lsp_server/src/world.rs b/crates/ra_lsp_server/src/world.rs
index 1ee02b47c..d993c5fc4 100644
--- a/crates/ra_lsp_server/src/world.rs
+++ b/crates/ra_lsp_server/src/world.rs
@@ -34,6 +34,7 @@ pub struct Options {
     pub supports_location_link: bool,
     pub line_folding_only: bool,
     pub max_inlay_hint_length: Option<usize>,
+    pub rustfmt_args: Vec<String>,
     pub cargo_watch: CheckOptions,
 }
 
diff --git a/crates/ra_lsp_server/tests/heavy_tests/main.rs b/crates/ra_lsp_server/tests/heavy_tests/main.rs
index dff63a12d..9ca31cbcc 100644
--- a/crates/ra_lsp_server/tests/heavy_tests/main.rs
+++ b/crates/ra_lsp_server/tests/heavy_tests/main.rs
@@ -147,7 +147,7 @@ fn main() {}
         },
         json!([
           {
-            "args": [ "test", "--package", "foo", "--test", "spam", "--", "test_eggs", "--nocapture" ],
+            "args": [ "test", "--package", "foo", "--test", "spam", "--", "test_eggs", "--exact", "--nocapture" ],
             "bin": "cargo",
             "env": { "RUST_BACKTRACE": "short" },
             "label": "test test_eggs",
diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index f154077a8..b72d2e9e6 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -336,7 +336,7 @@ fn for_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
 fn cond(p: &mut Parser) {
     let m = p.start();
     if p.eat(T![let]) {
-        patterns::pattern_list(p);
+        patterns::pattern_top(p);
         p.expect(T![=]);
     }
     expr_no_struct(p);
@@ -430,7 +430,7 @@ fn match_arm(p: &mut Parser) -> BlockLike {
     // }
     attributes::outer_attributes(p);
 
-    patterns::pattern_list_r(p, TokenSet::EMPTY);
+    patterns::pattern_top_r(p, TokenSet::EMPTY);
     if p.at(T![if]) {
         match_guard(p);
     }
diff --git a/crates/ra_parser/src/grammar/params.rs b/crates/ra_parser/src/grammar/params.rs
index 94edc7f35..272661b1d 100644
--- a/crates/ra_parser/src/grammar/params.rs
+++ b/crates/ra_parser/src/grammar/params.rs
@@ -114,9 +114,12 @@ 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![::]) {
-                patterns::pattern(p);
+            if (p.at(IDENT) || p.at(UNDERSCORE)) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
+                patterns::pattern_single(p);
                 types::ascription(p);
             } else {
                 types::type_(p);
@@ -127,7 +130,7 @@ fn value_parameter(p: &mut Parser, flavor: Flavor) {
         //    let foo = |bar, baz: Baz, qux: Qux::Quux| ();
         // }
         Flavor::Closure => {
-            patterns::pattern(p);
+            patterns::pattern_single(p);
             if p.at(T![:]) && !p.at(T![::]) {
                 types::ascription(p);
             }
diff --git a/crates/ra_parser/src/grammar/patterns.rs b/crates/ra_parser/src/grammar/patterns.rs
index 422a4e3dc..3afbaa82b 100644
--- a/crates/ra_parser/src/grammar/patterns.rs
+++ b/crates/ra_parser/src/grammar/patterns.rs
@@ -11,22 +11,47 @@ pub(crate) fn pattern(p: &mut Parser) {
 }
 
 /// Parses a pattern list separated by pipes `|`
-pub(super) fn pattern_list(p: &mut Parser) {
-    pattern_list_r(p, PAT_RECOVERY_SET)
+pub(super) fn pattern_top(p: &mut Parser) {
+    pattern_top_r(p, PAT_RECOVERY_SET)
+}
+
+pub(crate) fn pattern_single(p: &mut Parser) {
+    pattern_single_r(p, PAT_RECOVERY_SET);
 }
 
 /// Parses a pattern list separated by pipes `|`
 /// using the given `recovery_set`
-pub(super) fn pattern_list_r(p: &mut Parser, recovery_set: TokenSet) {
+pub(super) fn pattern_top_r(p: &mut Parser, recovery_set: TokenSet) {
     p.eat(T![|]);
     pattern_r(p, recovery_set);
+}
 
+/// Parses a pattern list separated by pipes `|`, with no leading `|`,using the
+/// given `recovery_set`
+// test or_pattern
+// fn main() {
+//     match () {
+//         (_ | _) => (),
+//         &(_ | _) => (),
+//         (_ | _,) => (),
+//         [_ | _,] => (),
+//     }
+// }
+fn pattern_r(p: &mut Parser, recovery_set: TokenSet) {
+    let m = p.start();
+    pattern_single_r(p, recovery_set);
+
+    if !p.at(T![|]) {
+        m.abandon(p);
+        return;
+    }
     while p.eat(T![|]) {
-        pattern_r(p, recovery_set);
+        pattern_single_r(p, recovery_set);
     }
+    m.complete(p, OR_PAT);
 }
 
-pub(super) fn pattern_r(p: &mut Parser, recovery_set: TokenSet) {
+fn pattern_single_r(p: &mut Parser, recovery_set: TokenSet) {
     if let Some(lhs) = atom_pat(p, recovery_set) {
         // test range_pat
         // fn main() {
@@ -258,19 +283,41 @@ fn ref_pat(p: &mut Parser) -> CompletedMarker {
     let m = p.start();
     p.bump(T![&]);
     p.eat(T![mut]);
-    pattern(p);
+    pattern_single(p);
     m.complete(p, REF_PAT)
 }
 
 // test tuple_pat
 // fn main() {
 //     let (a, b, ..) = ();
+//     let (a,) = ();
+//     let (..) = ();
+//     let () = ();
 // }
 fn tuple_pat(p: &mut Parser) -> CompletedMarker {
     assert!(p.at(T!['(']));
     let m = p.start();
-    tuple_pat_fields(p);
-    m.complete(p, TUPLE_PAT)
+    p.bump(T!['(']);
+    let mut has_comma = false;
+    let mut has_pat = false;
+    let mut has_rest = false;
+    while !p.at(EOF) && !p.at(T![')']) {
+        has_pat = true;
+        if !p.at_ts(PATTERN_FIRST) {
+            p.error("expected a pattern");
+            break;
+        }
+        has_rest |= p.at(T![..]);
+
+        pattern(p);
+        if !p.at(T![')']) {
+            has_comma = true;
+            p.expect(T![,]);
+        }
+    }
+    p.expect(T![')']);
+
+    m.complete(p, if !has_comma && !has_rest && has_pat { PAREN_PAT } else { TUPLE_PAT })
 }
 
 // test slice_pat
@@ -315,7 +362,7 @@ fn bind_pat(p: &mut Parser, with_at: bool) -> CompletedMarker {
     p.eat(T![mut]);
     name(p);
     if with_at && p.eat(T![@]) {
-        pattern(p);
+        pattern_single(p);
     }
     m.complete(p, BIND_PAT)
 }
@@ -330,6 +377,6 @@ fn box_pat(p: &mut Parser) -> CompletedMarker {
     assert!(p.at(T![box]));
     let m = p.start();
     p.bump(T![box]);
-    pattern(p);
+    pattern_single(p);
     m.complete(p, BOX_PAT)
 }
diff --git a/crates/ra_parser/src/syntax_kind/generated.rs b/crates/ra_parser/src/syntax_kind/generated.rs
index e27b27ffa..1068da0a0 100644
--- a/crates/ra_parser/src/syntax_kind/generated.rs
+++ b/crates/ra_parser/src/syntax_kind/generated.rs
@@ -151,6 +151,8 @@ pub enum SyntaxKind {
     FOR_TYPE,
     IMPL_TRAIT_TYPE,
     DYN_TRAIT_TYPE,
+    OR_PAT,
+    PAREN_PAT,
     REF_PAT,
     BOX_PAT,
     BIND_PAT,
diff --git a/crates/ra_prof/src/lib.rs b/crates/ra_prof/src/lib.rs
index d38ff397e..c0bfbc2ee 100644
--- a/crates/ra_prof/src/lib.rs
+++ b/crates/ra_prof/src/lib.rs
@@ -26,6 +26,13 @@ pub use crate::memory_usage::{Bytes, MemoryUsage};
 #[global_allocator]
 static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;
 
+pub fn init() {
+    set_filter(match std::env::var("RA_PROFILE") {
+        Ok(spec) => Filter::from_spec(&spec),
+        Err(_) => Filter::disabled(),
+    });
+}
+
 /// Set profiling filter. It specifies descriptions allowed to profile.
 /// This is helpful when call stack has too many nested profiling scopes.
 /// Additionally filter can specify maximum depth of profiling scopes nesting.
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 34d066b1e..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\
@@ -99,9 +98,15 @@ fn try_find_src_path(cargo_toml: &Path) -> Result<PathBuf> {
     let rustc_output = Command::new("rustc")
         .current_dir(cargo_toml.parent().unwrap())
         .args(&["--print", "sysroot"])
-        .output()?;
+        .output()
+        .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/src/ast.rs b/crates/ra_syntax/src/ast.rs
index 89cb9a9f3..9cc7930f7 100644
--- a/crates/ra_syntax/src/ast.rs
+++ b/crates/ra_syntax/src/ast.rs
@@ -18,7 +18,8 @@ use crate::{
 pub use self::{
     expr_extensions::{ArrayExprKind, BinOp, ElseBranch, LiteralKind, PrefixOp, RangeOp},
     extensions::{
-        FieldKind, PathSegmentKind, SelfParamKind, StructKind, TypeBoundKind, VisibilityKind,
+        AttrKind, FieldKind, PathSegmentKind, SelfParamKind, SlicePatComponents, StructKind,
+        TypeBoundKind, VisibilityKind,
     },
     generated::*,
     tokens::*,
@@ -216,10 +217,7 @@ fn test_doc_comment_multi_line_block_strips_suffix() {
 #[test]
 fn test_comments_preserve_trailing_whitespace() {
     let file = SourceFile::parse(
-        r#"
-/// Representation of a Realm.   
-/// In the specification these are called Realm Records.
-struct Realm {}"#,
+        "\n/// Representation of a Realm.   \n/// In the specification these are called Realm Records.\nstruct Realm {}",
     )
     .ok()
     .unwrap();
diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index cb0aee422..44de4af89 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -1,6 +1,8 @@
 //! Various extension methods to ast Nodes, which are hard to code-generate.
 //! Extensions for various expressions live in a sibling `expr_extensions` module.
 
+use itertools::Itertools;
+
 use crate::{
     ast::{self, child_opt, children, AstNode, AttrInput, SyntaxNode},
     SmolStr, SyntaxElement,
@@ -35,6 +37,12 @@ fn text_of_first_token(node: &SyntaxNode) -> &SmolStr {
     node.green().children().next().and_then(|it| it.into_token()).unwrap().text()
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum AttrKind {
+    Inner,
+    Outer,
+}
+
 impl ast::Attr {
     pub fn as_simple_atom(&self) -> Option<SmolStr> {
         match self.input() {
@@ -69,6 +77,18 @@ impl ast::Attr {
             _ => None,
         }
     }
+
+    pub fn kind(&self) -> AttrKind {
+        let first_token = self.syntax().first_token();
+        let first_token_kind = first_token.as_ref().map(SyntaxToken::kind);
+        let second_token_kind =
+            first_token.and_then(|token| token.next_token()).as_ref().map(SyntaxToken::kind);
+
+        match (first_token_kind, second_token_kind) {
+            (Some(SyntaxKind::POUND), Some(SyntaxKind::EXCL)) => AttrKind::Inner,
+            _ => AttrKind::Outer,
+        }
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -293,6 +313,40 @@ impl ast::BindPat {
     }
 }
 
+pub struct SlicePatComponents {
+    pub prefix: Vec<ast::Pat>,
+    pub slice: Option<ast::Pat>,
+    pub suffix: Vec<ast::Pat>,
+}
+
+impl ast::SlicePat {
+    pub fn components(&self) -> SlicePatComponents {
+        let mut args = self.args().peekable();
+        let prefix = args
+            .peeking_take_while(|p| match p {
+                ast::Pat::DotDotPat(_) => false,
+                ast::Pat::BindPat(bp) => match bp.pat() {
+                    Some(ast::Pat::DotDotPat(_)) => false,
+                    _ => true,
+                },
+                ast::Pat::RefPat(rp) => match rp.pat() {
+                    Some(ast::Pat::DotDotPat(_)) => false,
+                    Some(ast::Pat::BindPat(bp)) => match bp.pat() {
+                        Some(ast::Pat::DotDotPat(_)) => false,
+                        _ => true,
+                    },
+                    _ => true,
+                },
+                _ => true,
+            })
+            .collect();
+        let slice = args.next();
+        let suffix = args.collect();
+
+        SlicePatComponents { prefix, slice, suffix }
+    }
+}
+
 impl ast::PointerType {
     pub fn is_mut(&self) -> bool {
         self.syntax().children_with_tokens().any(|n| n.kind() == T![mut])
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 435135f92..8eb240801 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -1759,8 +1759,8 @@ impl AstNode for MatchArm {
 }
 impl ast::AttrsOwner for MatchArm {}
 impl MatchArm {
-    pub fn pats(&self) -> AstChildren<Pat> {
-        AstChildren::new(&self.syntax)
+    pub fn pat(&self) -> Option<Pat> {
+        AstChildren::new(&self.syntax).next()
     }
     pub fn guard(&self) -> Option<MatchGuard> {
         AstChildren::new(&self.syntax).next()
@@ -1887,6 +1887,60 @@ impl RecordField {
     }
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct OrPat {
+    pub(crate) syntax: SyntaxNode,
+}
+impl AstNode for OrPat {
+    fn can_cast(kind: SyntaxKind) -> bool {
+        match kind {
+            OR_PAT => true,
+            _ => false,
+        }
+    }
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl OrPat {
+    pub fn pats(&self) -> AstChildren<Pat> {
+        AstChildren::new(&self.syntax)
+    }
+}
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct ParenPat {
+    pub(crate) syntax: SyntaxNode,
+}
+impl AstNode for ParenPat {
+    fn can_cast(kind: SyntaxKind) -> bool {
+        match kind {
+            PAREN_PAT => true,
+            _ => false,
+        }
+    }
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode {
+        &self.syntax
+    }
+}
+impl ParenPat {
+    pub fn pat(&self) -> Option<Pat> {
+        AstChildren::new(&self.syntax).next()
+    }
+}
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct RefPat {
     pub(crate) syntax: SyntaxNode,
 }
@@ -2063,7 +2117,11 @@ impl AstNode for SlicePat {
         &self.syntax
     }
 }
-impl SlicePat {}
+impl SlicePat {
+    pub fn args(&self) -> AstChildren<Pat> {
+        AstChildren::new(&self.syntax)
+    }
+}
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct RangePat {
     pub(crate) syntax: SyntaxNode,
@@ -3900,6 +3958,8 @@ impl AstNode for Expr {
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Pat {
+    OrPat(OrPat),
+    ParenPat(ParenPat),
     RefPat(RefPat),
     BoxPat(BoxPat),
     BindPat(BindPat),
@@ -3913,6 +3973,16 @@ pub enum Pat {
     RangePat(RangePat),
     LiteralPat(LiteralPat),
 }
+impl From<OrPat> for Pat {
+    fn from(node: OrPat) -> Pat {
+        Pat::OrPat(node)
+    }
+}
+impl From<ParenPat> for Pat {
+    fn from(node: ParenPat) -> Pat {
+        Pat::ParenPat(node)
+    }
+}
 impl From<RefPat> for Pat {
     fn from(node: RefPat) -> Pat {
         Pat::RefPat(node)
@@ -3976,15 +4046,16 @@ impl From<LiteralPat> for Pat {
 impl AstNode for Pat {
     fn can_cast(kind: SyntaxKind) -> bool {
         match kind {
-            REF_PAT | BOX_PAT | BIND_PAT | PLACEHOLDER_PAT | DOT_DOT_PAT | PATH_PAT
-            | RECORD_PAT | TUPLE_STRUCT_PAT | TUPLE_PAT | SLICE_PAT | RANGE_PAT | LITERAL_PAT => {
-                true
-            }
+            OR_PAT | PAREN_PAT | REF_PAT | BOX_PAT | BIND_PAT | PLACEHOLDER_PAT | DOT_DOT_PAT
+            | PATH_PAT | RECORD_PAT | TUPLE_STRUCT_PAT | TUPLE_PAT | SLICE_PAT | RANGE_PAT
+            | LITERAL_PAT => true,
             _ => false,
         }
     }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
         let res = match syntax.kind() {
+            OR_PAT => Pat::OrPat(OrPat { syntax }),
+            PAREN_PAT => Pat::ParenPat(ParenPat { syntax }),
             REF_PAT => Pat::RefPat(RefPat { syntax }),
             BOX_PAT => Pat::BoxPat(BoxPat { syntax }),
             BIND_PAT => Pat::BindPat(BindPat { syntax }),
@@ -4003,6 +4074,8 @@ impl AstNode for Pat {
     }
     fn syntax(&self) -> &SyntaxNode {
         match self {
+            Pat::OrPat(it) => &it.syntax,
+            Pat::ParenPat(it) => &it.syntax,
             Pat::RefPat(it) => &it.syntax,
             Pat::BoxPat(it) => &it.syntax,
             Pat::BindPat(it) => &it.syntax,
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0030_cond.txt b/crates/ra_syntax/test_data/parser/inline/ok/0030_cond.txt
index 4028ca243..6fd49c7bc 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0030_cond.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0030_cond.txt
@@ -63,27 +63,28 @@ SOURCE_FILE@[0; 197)
             CONDITION@[56; 84)
               LET_KW@[56; 59) "let"
               WHITESPACE@[59; 60) " "
-              TUPLE_STRUCT_PAT@[60; 67)
-                PATH@[60; 64)
-                  PATH_SEGMENT@[60; 64)
-                    NAME_REF@[60; 64)
-                      IDENT@[60; 64) "Some"
-                L_PAREN@[64; 65) "("
-                PLACEHOLDER_PAT@[65; 66)
-                  UNDERSCORE@[65; 66) "_"
-                R_PAREN@[66; 67) ")"
-              WHITESPACE@[67; 68) " "
-              PIPE@[68; 69) "|"
-              WHITESPACE@[69; 70) " "
-              TUPLE_STRUCT_PAT@[70; 77)
-                PATH@[70; 74)
-                  PATH_SEGMENT@[70; 74)
-                    NAME_REF@[70; 74)
-                      IDENT@[70; 74) "Some"
-                L_PAREN@[74; 75) "("
-                PLACEHOLDER_PAT@[75; 76)
-                  UNDERSCORE@[75; 76) "_"
-                R_PAREN@[76; 77) ")"
+              OR_PAT@[60; 77)
+                TUPLE_STRUCT_PAT@[60; 67)
+                  PATH@[60; 64)
+                    PATH_SEGMENT@[60; 64)
+                      NAME_REF@[60; 64)
+                        IDENT@[60; 64) "Some"
+                  L_PAREN@[64; 65) "("
+                  PLACEHOLDER_PAT@[65; 66)
+                    UNDERSCORE@[65; 66) "_"
+                  R_PAREN@[66; 67) ")"
+                WHITESPACE@[67; 68) " "
+                PIPE@[68; 69) "|"
+                WHITESPACE@[69; 70) " "
+                TUPLE_STRUCT_PAT@[70; 77)
+                  PATH@[70; 74)
+                    PATH_SEGMENT@[70; 74)
+                      NAME_REF@[70; 74)
+                        IDENT@[70; 74) "Some"
+                  L_PAREN@[74; 75) "("
+                  PLACEHOLDER_PAT@[75; 76)
+                    UNDERSCORE@[75; 76) "_"
+                  R_PAREN@[76; 77) ")"
               WHITESPACE@[77; 78) " "
               EQ@[78; 79) "="
               WHITESPACE@[79; 80) " "
@@ -137,27 +138,28 @@ SOURCE_FILE@[0; 197)
             CONDITION@[129; 157)
               LET_KW@[129; 132) "let"
               WHITESPACE@[132; 133) " "
-              TUPLE_STRUCT_PAT@[133; 140)
-                PATH@[133; 137)
-                  PATH_SEGMENT@[133; 137)
-                    NAME_REF@[133; 137)
-                      IDENT@[133; 137) "Some"
-                L_PAREN@[137; 138) "("
-                PLACEHOLDER_PAT@[138; 139)
-                  UNDERSCORE@[138; 139) "_"
-                R_PAREN@[139; 140) ")"
-              WHITESPACE@[140; 141) " "
-              PIPE@[141; 142) "|"
-              WHITESPACE@[142; 143) " "
-              TUPLE_STRUCT_PAT@[143; 150)
-                PATH@[143; 147)
-                  PATH_SEGMENT@[143; 147)
-                    NAME_REF@[143; 147)
-                      IDENT@[143; 147) "Some"
-                L_PAREN@[147; 148) "("
-                PLACEHOLDER_PAT@[148; 149)
-                  UNDERSCORE@[148; 149) "_"
-                R_PAREN@[149; 150) ")"
+              OR_PAT@[133; 150)
+                TUPLE_STRUCT_PAT@[133; 140)
+                  PATH@[133; 137)
+                    PATH_SEGMENT@[133; 137)
+                      NAME_REF@[133; 137)
+                        IDENT@[133; 137) "Some"
+                  L_PAREN@[137; 138) "("
+                  PLACEHOLDER_PAT@[138; 139)
+                    UNDERSCORE@[138; 139) "_"
+                  R_PAREN@[139; 140) ")"
+                WHITESPACE@[140; 141) " "
+                PIPE@[141; 142) "|"
+                WHITESPACE@[142; 143) " "
+                TUPLE_STRUCT_PAT@[143; 150)
+                  PATH@[143; 147)
+                    PATH_SEGMENT@[143; 147)
+                      NAME_REF@[143; 147)
+                        IDENT@[143; 147) "Some"
+                  L_PAREN@[147; 148) "("
+                  PLACEHOLDER_PAT@[148; 149)
+                    UNDERSCORE@[148; 149) "_"
+                  R_PAREN@[149; 150) ")"
               WHITESPACE@[150; 151) " "
               EQ@[151; 152) "="
               WHITESPACE@[152; 153) " "
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0066_match_arm.txt b/crates/ra_syntax/test_data/parser/inline/ok/0066_match_arm.txt
index 87272917b..2f07af4e1 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0066_match_arm.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0066_match_arm.txt
@@ -74,15 +74,16 @@ SOURCE_FILE@[0; 167)
               COMMA@[83; 84) ","
               WHITESPACE@[84; 93) "\n        "
               MATCH_ARM@[93; 109)
-                BIND_PAT@[93; 94)
-                  NAME@[93; 94)
-                    IDENT@[93; 94) "X"
-                WHITESPACE@[94; 95) " "
-                PIPE@[95; 96) "|"
-                WHITESPACE@[96; 97) " "
-                BIND_PAT@[97; 98)
-                  NAME@[97; 98)
-                    IDENT@[97; 98) "Y"
+                OR_PAT@[93; 98)
+                  BIND_PAT@[93; 94)
+                    NAME@[93; 94)
+                      IDENT@[93; 94) "X"
+                  WHITESPACE@[94; 95) " "
+                  PIPE@[95; 96) "|"
+                  WHITESPACE@[96; 97) " "
+                  BIND_PAT@[97; 98)
+                    NAME@[97; 98)
+                      IDENT@[97; 98) "Y"
                 WHITESPACE@[98; 99) " "
                 MATCH_GUARD@[99; 103)
                   IF_KW@[99; 101) "if"
@@ -103,15 +104,16 @@ SOURCE_FILE@[0; 167)
               MATCH_ARM@[119; 137)
                 PIPE@[119; 120) "|"
                 WHITESPACE@[120; 121) " "
-                BIND_PAT@[121; 122)
-                  NAME@[121; 122)
-                    IDENT@[121; 122) "X"
-                WHITESPACE@[122; 123) " "
-                PIPE@[123; 124) "|"
-                WHITESPACE@[124; 125) " "
-                BIND_PAT@[125; 126)
-                  NAME@[125; 126)
-                    IDENT@[125; 126) "Y"
+                OR_PAT@[121; 126)
+                  BIND_PAT@[121; 122)
+                    NAME@[121; 122)
+                      IDENT@[121; 122) "X"
+                  WHITESPACE@[122; 123) " "
+                  PIPE@[123; 124) "|"
+                  WHITESPACE@[124; 125) " "
+                  BIND_PAT@[125; 126)
+                    NAME@[125; 126)
+                      IDENT@[125; 126) "Y"
                 WHITESPACE@[126; 127) " "
                 MATCH_GUARD@[127; 131)
                   IF_KW@[127; 129) "if"
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.rs b/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.rs
index f785acd36..ba719879d 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.rs
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.rs
@@ -1,3 +1,6 @@
 fn main() {
     let (a, b, ..) = ();
+    let (a,) = ();
+    let (..) = ();
+    let () = ();
 }
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.txt b/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.txt
index 674dec493..4680c267e 100644
--- a/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.txt
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0111_tuple_pat.txt
@@ -1,5 +1,5 @@
-SOURCE_FILE@[0; 39)
-  FN_DEF@[0; 38)
+SOURCE_FILE@[0; 94)
+  FN_DEF@[0; 93)
     FN_KW@[0; 2) "fn"
     WHITESPACE@[2; 3) " "
     NAME@[3; 7)
@@ -8,8 +8,8 @@ SOURCE_FILE@[0; 39)
       L_PAREN@[7; 8) "("
       R_PAREN@[8; 9) ")"
     WHITESPACE@[9; 10) " "
-    BLOCK_EXPR@[10; 38)
-      BLOCK@[10; 38)
+    BLOCK_EXPR@[10; 93)
+      BLOCK@[10; 93)
         L_CURLY@[10; 11) "{"
         WHITESPACE@[11; 16) "\n    "
         LET_STMT@[16; 36)
@@ -37,6 +37,54 @@ SOURCE_FILE@[0; 39)
             L_PAREN@[33; 34) "("
             R_PAREN@[34; 35) ")"
           SEMI@[35; 36) ";"
-        WHITESPACE@[36; 37) "\n"
-        R_CURLY@[37; 38) "}"
-  WHITESPACE@[38; 39) "\n"
+        WHITESPACE@[36; 41) "\n    "
+        LET_STMT@[41; 55)
+          LET_KW@[41; 44) "let"
+          WHITESPACE@[44; 45) " "
+          TUPLE_PAT@[45; 49)
+            L_PAREN@[45; 46) "("
+            BIND_PAT@[46; 47)
+              NAME@[46; 47)
+                IDENT@[46; 47) "a"
+            COMMA@[47; 48) ","
+            R_PAREN@[48; 49) ")"
+          WHITESPACE@[49; 50) " "
+          EQ@[50; 51) "="
+          WHITESPACE@[51; 52) " "
+          TUPLE_EXPR@[52; 54)
+            L_PAREN@[52; 53) "("
+            R_PAREN@[53; 54) ")"
+          SEMI@[54; 55) ";"
+        WHITESPACE@[55; 60) "\n    "
+        LET_STMT@[60; 74)
+          LET_KW@[60; 63) "let"
+          WHITESPACE@[63; 64) " "
+          TUPLE_PAT@[64; 68)
+            L_PAREN@[64; 65) "("
+            DOT_DOT_PAT@[65; 67)
+              DOTDOT@[65; 67) ".."
+            R_PAREN@[67; 68) ")"
+          WHITESPACE@[68; 69) " "
+          EQ@[69; 70) "="
+          WHITESPACE@[70; 71) " "
+          TUPLE_EXPR@[71; 73)
+            L_PAREN@[71; 72) "("
+            R_PAREN@[72; 73) ")"
+          SEMI@[73; 74) ";"
+        WHITESPACE@[74; 79) "\n    "
+        LET_STMT@[79; 91)
+          LET_KW@[79; 82) "let"
+          WHITESPACE@[82; 83) " "
+          TUPLE_PAT@[83; 85)
+            L_PAREN@[83; 84) "("
+            R_PAREN@[84; 85) ")"
+          WHITESPACE@[85; 86) " "
+          EQ@[86; 87) "="
+          WHITESPACE@[87; 88) " "
+          TUPLE_EXPR@[88; 90)
+            L_PAREN@[88; 89) "("
+            R_PAREN@[89; 90) ")"
+          SEMI@[90; 91) ";"
+        WHITESPACE@[91; 92) "\n"
+        R_CURLY@[92; 93) "}"
+  WHITESPACE@[93; 94) "\n"
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.rs b/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.rs
new file mode 100644
index 000000000..a26316605
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.rs
@@ -0,0 +1,8 @@
+fn main() {
+    match () {
+        (_ | _) => (),
+        &(_ | _) => (),
+        (_ | _,) => (),
+        [_ | _,] => (),
+    }
+}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.txt b/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.txt
new file mode 100644
index 000000000..3a196d3c0
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0156_or_pattern.txt
@@ -0,0 +1,112 @@
+SOURCE_FILE@[0; 130)
+  FN_DEF@[0; 129)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 7)
+      IDENT@[3; 7) "main"
+    PARAM_LIST@[7; 9)
+      L_PAREN@[7; 8) "("
+      R_PAREN@[8; 9) ")"
+    WHITESPACE@[9; 10) " "
+    BLOCK_EXPR@[10; 129)
+      BLOCK@[10; 129)
+        L_CURLY@[10; 11) "{"
+        WHITESPACE@[11; 16) "\n    "
+        MATCH_EXPR@[16; 127)
+          MATCH_KW@[16; 21) "match"
+          WHITESPACE@[21; 22) " "
+          TUPLE_EXPR@[22; 24)
+            L_PAREN@[22; 23) "("
+            R_PAREN@[23; 24) ")"
+          WHITESPACE@[24; 25) " "
+          MATCH_ARM_LIST@[25; 127)
+            L_CURLY@[25; 26) "{"
+            WHITESPACE@[26; 35) "\n        "
+            MATCH_ARM@[35; 48)
+              PAREN_PAT@[35; 42)
+                L_PAREN@[35; 36) "("
+                OR_PAT@[36; 41)
+                  PLACEHOLDER_PAT@[36; 37)
+                    UNDERSCORE@[36; 37) "_"
+                  WHITESPACE@[37; 38) " "
+                  PIPE@[38; 39) "|"
+                  WHITESPACE@[39; 40) " "
+                  PLACEHOLDER_PAT@[40; 41)
+                    UNDERSCORE@[40; 41) "_"
+                R_PAREN@[41; 42) ")"
+              WHITESPACE@[42; 43) " "
+              FAT_ARROW@[43; 45) "=>"
+              WHITESPACE@[45; 46) " "
+              TUPLE_EXPR@[46; 48)
+                L_PAREN@[46; 47) "("
+                R_PAREN@[47; 48) ")"
+            COMMA@[48; 49) ","
+            WHITESPACE@[49; 58) "\n        "
+            MATCH_ARM@[58; 72)
+              REF_PAT@[58; 66)
+                AMP@[58; 59) "&"
+                PAREN_PAT@[59; 66)
+                  L_PAREN@[59; 60) "("
+                  OR_PAT@[60; 65)
+                    PLACEHOLDER_PAT@[60; 61)
+                      UNDERSCORE@[60; 61) "_"
+                    WHITESPACE@[61; 62) " "
+                    PIPE@[62; 63) "|"
+                    WHITESPACE@[63; 64) " "
+                    PLACEHOLDER_PAT@[64; 65)
+                      UNDERSCORE@[64; 65) "_"
+                  R_PAREN@[65; 66) ")"
+              WHITESPACE@[66; 67) " "
+              FAT_ARROW@[67; 69) "=>"
+              WHITESPACE@[69; 70) " "
+              TUPLE_EXPR@[70; 72)
+                L_PAREN@[70; 71) "("
+                R_PAREN@[71; 72) ")"
+            COMMA@[72; 73) ","
+            WHITESPACE@[73; 82) "\n        "
+            MATCH_ARM@[82; 96)
+              TUPLE_PAT@[82; 90)
+                L_PAREN@[82; 83) "("
+                OR_PAT@[83; 88)
+                  PLACEHOLDER_PAT@[83; 84)
+                    UNDERSCORE@[83; 84) "_"
+                  WHITESPACE@[84; 85) " "
+                  PIPE@[85; 86) "|"
+                  WHITESPACE@[86; 87) " "
+                  PLACEHOLDER_PAT@[87; 88)
+                    UNDERSCORE@[87; 88) "_"
+                COMMA@[88; 89) ","
+                R_PAREN@[89; 90) ")"
+              WHITESPACE@[90; 91) " "
+              FAT_ARROW@[91; 93) "=>"
+              WHITESPACE@[93; 94) " "
+              TUPLE_EXPR@[94; 96)
+                L_PAREN@[94; 95) "("
+                R_PAREN@[95; 96) ")"
+            COMMA@[96; 97) ","
+            WHITESPACE@[97; 106) "\n        "
+            MATCH_ARM@[106; 120)
+              SLICE_PAT@[106; 114)
+                L_BRACK@[106; 107) "["
+                OR_PAT@[107; 112)
+                  PLACEHOLDER_PAT@[107; 108)
+                    UNDERSCORE@[107; 108) "_"
+                  WHITESPACE@[108; 109) " "
+                  PIPE@[109; 110) "|"
+                  WHITESPACE@[110; 111) " "
+                  PLACEHOLDER_PAT@[111; 112)
+                    UNDERSCORE@[111; 112) "_"
+                COMMA@[112; 113) ","
+                R_BRACK@[113; 114) "]"
+              WHITESPACE@[114; 115) " "
+              FAT_ARROW@[115; 117) "=>"
+              WHITESPACE@[117; 118) " "
+              TUPLE_EXPR@[118; 120)
+                L_PAREN@[118; 119) "("
+                R_PAREN@[119; 120) ")"
+            COMMA@[120; 121) ","
+            WHITESPACE@[121; 126) "\n    "
+            R_CURLY@[126; 127) "}"
+        WHITESPACE@[127; 128) "\n"
+        R_CURLY@[128; 129) "}"
+  WHITESPACE@[129; 130) "\n"
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/crates/ra_text_edit/src/lib.rs b/crates/ra_text_edit/src/lib.rs
index 5f1b12222..37f23d043 100644
--- a/crates/ra_text_edit/src/lib.rs
+++ b/crates/ra_text_edit/src/lib.rs
@@ -29,8 +29,8 @@ impl AtomTextEdit {
     }
 
     pub fn apply(&self, mut text: String) -> String {
-        let start = u32::from(self.delete.start()) as usize;
-        let end = u32::from(self.delete.end()) as usize;
+        let start = self.delete.start().to_usize();
+        let end = self.delete.end().to_usize();
         text.replace_range(start..end, &self.insert);
         text
     }
diff --git a/crates/ra_text_edit/src/text_edit.rs b/crates/ra_text_edit/src/text_edit.rs
index 413c7d782..3291ada42 100644
--- a/crates/ra_text_edit/src/text_edit.rs
+++ b/crates/ra_text_edit/src/text_edit.rs
@@ -66,13 +66,13 @@ impl TextEdit {
         let mut total_len = text.len();
         for atom in self.atoms.iter() {
             total_len += atom.insert.len();
-            total_len -= u32::from(atom.delete.end() - atom.delete.start()) as usize;
+            total_len -= (atom.delete.end() - atom.delete.start()).to_usize();
         }
         let mut buf = String::with_capacity(total_len);
         let mut prev = 0;
         for atom in self.atoms.iter() {
-            let start = u32::from(atom.delete.start()) as usize;
-            let end = u32::from(atom.delete.end()) as usize;
+            let start = atom.delete.start().to_usize();
+            let end = atom.delete.end().to_usize();
             if start > prev {
                 buf.push_str(&text[prev..start]);
             }
diff --git a/docs/dev/README.md b/docs/dev/README.md
index 732e4bdd3..991deaf90 100644
--- a/docs/dev/README.md
+++ b/docs/dev/README.md
@@ -74,7 +74,7 @@ relevant test and execute it (VS Code includes an action for running a single
 test).
 
 However, launching a VS Code instance with locally build language server is
-possible. There's "Run Extension (Dev Server)" launch configuration for this.
+possible. There's **"Run Extension (Dev Server)"** launch configuration for this.
 
 In general, I use one of the following workflows for fixing bugs and
 implementing features.
@@ -88,7 +88,14 @@ Code to sanity check that the thing works as I expect.
 
 If the problem concerns only the VS Code extension, I use **Run Extension**
 launch configuration from `launch.json`. Notably, this uses the usual
-`ra_lsp_server` binary from `PATH`. After I am done with the fix, I use `cargo
+`ra_lsp_server` binary from `PATH`. For this it is important to have the following
+in `setting.json` file:
+```json
+{
+    "rust-analyzer.raLspServerPath": "ra_lsp_server"
+}
+```
+After I am done with the fix, I use `cargo
 xtask install --client-code` to try the new extension for real.
 
 If I need to fix something in the `ra_lsp_server` crate, I feel sad because it's
diff --git a/docs/dev/debugging.md b/docs/dev/debugging.md
index 1ccf4dca2..e6b082156 100644
--- a/docs/dev/debugging.md
+++ b/docs/dev/debugging.md
@@ -1,44 +1,66 @@
-# Debugging vs Code plugin and the Language Server
+# Debugging VSCode plugin and the language server
 
-**NOTE:** the information here is mostly obsolete
+## Prerequisites
 
-Install [LLDB](https://lldb.llvm.org/) and the [LLDB Extension](https://marketplace.visualstudio.com/items?itemName=vadimcn.vscode-lldb).
+- Install [LLDB](https://lldb.llvm.org/) and the [LLDB Extension](https://marketplace.visualstudio.com/items?itemName=vadimcn.vscode-lldb).
+- Open the root folder in VSCode. Here you can access the preconfigured debug setups.
 
-Checkout rust rust-analyzer and open it in vscode.
+  <img height=150px src="https://user-images.githubusercontent.com/36276403/74611090-92ec5380-5101-11ea-8a41-598f51f3f3e3.png" alt="Debug options view">
+
+- Install all TypeScript dependencies
+  ```bash
+  cd editors/code
+  npm install
+  ```
+
+## Common knowledge
+
+* All debug configurations open a new `[Extension Development Host]` VSCode instance
+where **only** the `rust-analyzer` extension being debugged is enabled.
+* To activate the extension you need to open any Rust project folder in `[Extension Development Host]`.
 
-```
-$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
-$ cd rust-analyzer
-$ code .
-```
 
-- To attach to the `lsp server` in linux you'll have to run:
+## Debug TypeScript VSCode extension
 
-  `echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope`
+- `Run Extension` - runs the extension with the globally installed `ra_lsp_server` binary.
+- `Run Extension (Dev Server)` - runs extension with the locally built LSP server (`target/debug/ra_lsp_server`).
+
+TypeScript debugging is configured to watch your source edits and recompile.
+To apply changes to an already running debug process press <kbd>Ctrl+Shift+P</kbd> and run the following command in your `[Extension Development Host]`
+
+```
+> Developer: Reload Window
+```
 
-  This enables ptrace on non forked processes
+## Debug Rust LSP server
 
-- Ensure the dependencies for the extension are installed, run the `npm: install - editors/code` task in vscode.
+- When attaching a debugger to an already running `rust-analyzer` server on Linux you might need to enable `ptrace` for unrelated processes by running:
 
-- Launch the `Debug Extension`, this will build the extension and the `lsp server`.
+  ```
+  echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
+  ```
 
-- A new instance of vscode with `[Extension Development Host]` in the title.
 
-  Don't worry about disabling `rls` all other extensions will be disabled but this one.
+- By default, the LSP server is built without debug information. To enable it, you'll need to change `Cargo.toml`:
+  ```toml
+    [profile.dev]
+    debug = 2
+  ```
 
-- In the new vscode instance open a rust project, and navigate to a rust file
+- Select `Run Extension (Dev Server)` to run your locally built `target/debug/ra_lsp_server`.
 
-- In the original vscode start an additional debug session (the three periods in the launch) and select `Debug Lsp Server`.
+- In the original VSCode window once again select the `Attach To Server` debug configuration.
 
-- A list of running processes should appear select the `ra_lsp_server` from this repo.
+- A list of running processes should appear. Select the `ra_lsp_server` from this repo.
 
 - Navigate to `crates/ra_lsp_server/src/main_loop.rs` and add a breakpoint to the `on_task` function.
 
-- Go back to the `[Extension Development Host]` instance and hover over a rust variable and your breakpoint should hit.
+- Go back to the `[Extension Development Host]` instance and hover over a Rust variable and your breakpoint should hit.
 
 ## Demo
 
-![demonstration of debugging](https://user-images.githubusercontent.com/1711539/51384036-254fab80-1b2c-11e9-824d-95f9a6e9cf4f.gif)
+- [Debugging TypeScript VScode extension](https://www.youtube.com/watch?v=T-hvpK6s4wM).
+- [Debugging Rust LSP server](https://www.youtube.com/watch?v=EaNb5rg4E0M).
 
 ## Troubleshooting
 
diff --git a/docs/user/README.md b/docs/user/README.md
deleted file mode 100644
index 3da30a193..000000000
--- a/docs/user/README.md
+++ /dev/null
@@ -1,250 +0,0 @@
-The main interface to rust-analyzer is the
-[LSP](https://microsoft.github.io/language-server-protocol/) implementation. To
-install lsp server, clone the repository and then run `cargo xtask install
---server` (which is shorthand for `cargo install --path
-./crates/ra_lsp_server`). This will produce a binary named `ra_lsp_server` which
-you should be able to use it with any LSP-compatible editor. We use 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.
-
-```
-$ git clone [email protected]:rust-analyzer/rust-analyzer && cd rust-analyzer
-$ cargo xtask install --server
-```
-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:
-
-In order to build the VS Code plugin, you need to have node.js and npm with
-a minimum version of 10 installed. Please refer to
-[node.js and npm documentation](https://nodejs.org) for installation instructions.
-
-You will also 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](https://github.com/rust-analyzer/rust-analyzer/releases).
-In order to use them you need to install the client VSCode extension.
-
-Publishing to VSCode marketplace is currently WIP. Thus, you need to clone the repository and install **only** the client extension via
-```
-$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
-$ cd rust-analyzer
-$ cargo xtask install --client-code
-```
-Then open VSCode (or reload the window if it was already running), 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 ${HOME}/.config/Code/User/globalStorage/matklad.rust-analyzer
-```
-
-`"Donwload latest language server"` command for VSCode and automatic updates detection is currently WIP.
-
-
-### Installation from sources
-
-The experimental VS Code plugin can be built and installed by executing the
-following commands:
-
-```
-$ git clone https://github.com/rust-analyzer/rust-analyzer.git --depth 1
-$ cd rust-analyzer
-$ cargo xtask install
-```
-
-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
-* `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)
-
-### 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..553687e78
--- /dev/null
+++ b/docs/user/readme.adoc
@@ -0,0 +1,154 @@
+= 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 matching version of the server as well.
+
+// FIXME: update the image (its text has changed)
+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. It will ask your permission to download the matching language server version binary if needed.
+
+==== 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 f687eb8d4..46acbfe76 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": "0.2.20200211-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",
@@ -181,9 +182,20 @@
                 },
                 "rust-analyzer.excludeGlobs": {
                     "type": "array",
+                    "items": {
+                        "type": "string"
+                    },
                     "default": [],
                     "description": "Paths to exclude from analysis"
                 },
+                "rust-analyzer.rustfmtArgs": {
+                    "type": "array",
+                    "items": {
+                        "type": "string"
+                    },
+                    "default": [],
+                    "description": "Additional arguments to rustfmt"
+                },
                 "rust-analyzer.useClientWatching": {
                     "type": "boolean",
                     "default": true,
@@ -196,6 +208,9 @@
                 },
                 "rust-analyzer.cargo-watch.arguments": {
                     "type": "array",
+                    "items": {
+                        "type": "string"
+                    },
                     "description": "`cargo-watch` arguments. (e.g: `--features=\"shumway,pdf\"` will run as `cargo watch -x \"check --features=\"shumway,pdf\"\"` )",
                     "default": []
                 },
@@ -227,10 +242,12 @@
                 },
                 "rust-analyzer.lruCapacity": {
                     "type": [
-                        "number",
-                        "null"
+                        "null",
+                        "integer"
                     ],
                     "default": null,
+                    "minimum": 0,
+                    "exclusiveMinimum": true,
                     "description": "Number of syntax trees rust-analyzer keeps in memory"
                 },
                 "rust-analyzer.displayInlayHints": {
@@ -239,8 +256,13 @@
                     "description": "Display additional type and parameter information in the editor"
                 },
                 "rust-analyzer.maxInlayHintLength": {
-                    "type": "number",
+                    "type": [
+                        "null",
+                        "integer"
+                    ],
                     "default": 20,
+                    "minimum": 0,
+                    "exclusiveMinimum": true,
                     "description": "Maximum length for inlay hints"
                 },
                 "rust-analyzer.cargoFeatures.noDefaultFeatures": {
@@ -255,6 +277,9 @@
                 },
                 "rust-analyzer.cargoFeatures.features": {
                     "type": "array",
+                    "items": {
+                        "type": "string"
+                    },
                     "default": [],
                     "description": "List of features to activate"
                 }
diff --git a/editors/code/rollup.config.js b/editors/code/rollup.config.js
index f8d320f46..337385a24 100644
--- a/editors/code/rollup.config.js
+++ b/editors/code/rollup.config.js
@@ -18,6 +18,7 @@ export default {
     external: [...nodeBuiltins, 'vscode'],
     output: {
         file: './out/main.js',
-        format: 'cjs'
+        format: 'cjs',
+        exports: 'named'
     }
 };
diff --git a/editors/code/src/client.ts b/editors/code/src/client.ts
index 2e3d4aba2..11894973c 100644
--- a/editors/code/src/client.ts
+++ b/editors/code/src/client.ts
@@ -1,44 +1,48 @@
 import * as lc from 'vscode-languageclient';
+import * as vscode from 'vscode';
 
-import { window, workspace } from 'vscode';
 import { Config } from './config';
-import { ensureLanguageServerBinary } from './installation/language_server';
+import { ensureServerBinary } from './installation/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
     // TODO?: Workspace folders support Uri's (eg: file://test.txt).
     // It might be a good idea to test if the uri points to a file.
-    const workspaceFolderPath = workspace.workspaceFolders?.[0]?.uri.fsPath ?? '.';
+    const workspaceFolderPath = vscode.workspace.workspaceFolders?.[0]?.uri.fsPath ?? '.';
 
-    const raLspServerPath = await ensureLanguageServerBinary(config.langServerSource);
-    if (!raLspServerPath) return null;
+    const serverPath = await ensureServerBinary(config.serverSource);
+    if (!serverPath) return null;
 
     const run: lc.Executable = {
-        command: raLspServerPath,
+        command: serverPath,
         options: { cwd: workspaceFolderPath },
     };
     const serverOptions: lc.ServerOptions = {
         run,
         debug: run,
     };
-    const traceOutputChannel = window.createOutputChannel(
+    const traceOutputChannel = vscode.window.createOutputChannel(
         'Rust Analyzer Language Server Trace',
     );
+    const cargoWatchOpts = config.cargoWatchOptions;
+
     const clientOptions: lc.LanguageClientOptions = {
         documentSelector: [{ scheme: 'file', language: 'rust' }],
         initializationOptions: {
             publishDecorations: true,
             lruCapacity: config.lruCapacity,
             maxInlayHintLength: config.maxInlayHintLength,
-            cargoWatchEnable: config.cargoWatchOptions.enable,
-            cargoWatchArgs: config.cargoWatchOptions.arguments,
-            cargoWatchCommand: config.cargoWatchOptions.command,
-            cargoWatchAllTargets: config.cargoWatchOptions.allTargets,
+            cargoWatchEnable: cargoWatchOpts.enable,
+            cargoWatchArgs: cargoWatchOpts.arguments,
+            cargoWatchCommand: cargoWatchOpts.command,
+            cargoWatchAllTargets: cargoWatchOpts.allTargets,
             excludeGlobs: config.excludeGlobs,
             useClientWatching: config.useClientWatching,
             featureFlags: config.featureFlags,
             withSysroot: config.withSysroot,
             cargoFeatures: config.cargoFeatures,
+            rustfmtArgs: config.rustfmtArgs,
         },
         traceOutputChannel,
     };
@@ -78,6 +82,10 @@ 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/config.ts b/editors/code/src/config.ts
index d5f3da2ed..c3fa788c7 100644
--- a/editors/code/src/config.ts
+++ b/editors/code/src/config.ts
@@ -16,45 +16,61 @@ export interface CargoFeatures {
     allFeatures: boolean;
     features: string[];
 }
-
 export class Config {
-    langServerSource!: null | BinarySource;
+    private static readonly rootSection = "rust-analyzer";
+    private static readonly requiresReloadOpts = [
+        "cargoFeatures",
+        "cargo-watch",
+    ]
+    .map(opt => `${Config.rootSection}.${opt}`);
+
+    private static readonly extensionVersion: string = (() => {
+        const packageJsonVersion = vscode
+            .extensions
+            .getExtension("matklad.rust-analyzer")!
+            .packageJSON
+            .version as string; // n.n.YYYYMMDD
+
+        const realVersionRegexp = /^\d+\.\d+\.(\d{4})(\d{2})(\d{2})/;
+        const [, yyyy, mm, dd] = packageJsonVersion.match(realVersionRegexp)!;
+
+        return `${yyyy}-${mm}-${dd}`;
+    })();
+
+    private cfg!: vscode.WorkspaceConfiguration;
+
+    constructor(private readonly ctx: vscode.ExtensionContext) {
+        vscode.workspace.onDidChangeConfiguration(this.onConfigChange, this, ctx.subscriptions);
+        this.refreshConfig();
+    }
 
-    highlightingOn = true;
-    rainbowHighlightingOn = false;
-    enableEnhancedTyping = true;
-    lruCapacity: null | number = null;
-    displayInlayHints = true;
-    maxInlayHintLength: null | number = null;
-    excludeGlobs: string[] = [];
-    useClientWatching = true;
-    featureFlags: Record<string, boolean> = {};
-    // for internal use
-    withSysroot: null | boolean = null;
-    cargoWatchOptions: CargoWatchOptions = {
-        enable: true,
-        arguments: [],
-        command: '',
-        allTargets: true,
-    };
-    cargoFeatures: CargoFeatures = {
-        noDefaultFeatures: false,
-        allFeatures: true,
-        features: [],
-    };
+    private refreshConfig() {
+        this.cfg = vscode.workspace.getConfiguration(Config.rootSection);
+        console.log("Using configuration:", this.cfg);
+    }
 
-    private prevEnhancedTyping: null | boolean = null;
-    private prevCargoFeatures: null | CargoFeatures = null;
-    private prevCargoWatchOptions: null | CargoWatchOptions = null;
+    private async onConfigChange(event: vscode.ConfigurationChangeEvent) {
+        this.refreshConfig();
 
-    constructor(ctx: vscode.ExtensionContext) {
-        vscode.workspace.onDidChangeConfiguration(_ => this.refresh(ctx), null, ctx.subscriptions);
-        this.refresh(ctx);
+        const requiresReloadOpt = Config.requiresReloadOpts.find(
+            opt => event.affectsConfiguration(opt)
+        );
+
+        if (!requiresReloadOpt) return;
+
+        const userResponse = await vscode.window.showInformationMessage(
+            `Changing "${requiresReloadOpt}" requires a reload`,
+            "Reload now"
+        );
+
+        if (userResponse === "Reload now") {
+            vscode.commands.executeCommand("workbench.action.reloadWindow");
+        }
     }
 
-    private static expandPathResolving(path: string) {
-        if (path.startsWith('~/')) {
-            return path.replace('~', os.homedir());
+    private static replaceTildeWithHomeDir(path: string) {
+        if (path.startsWith("~/")) {
+            return os.homedir() + path.slice("~".length);
         }
         return path;
     }
@@ -64,9 +80,21 @@ export class Config {
      * `platform` on GitHub releases. (It is also stored under the same name when
      * downloaded by the extension).
      */
-    private static prebuiltLangServerFileName(platform: NodeJS.Platform): null | string {
-        switch (platform) {
-            case "linux":  return "ra_lsp_server-linux";
+    get prebuiltServerFileName(): null | string {
+        // See possible `arch` values here:
+        // https://nodejs.org/api/process.html#process_process_arch
+
+        switch (process.platform) {
+
+            case "linux": {
+                switch (process.arch) {
+                    case "arm":
+                    case "arm64": return null;
+
+                    default: return "ra_lsp_server-linux";
+                }
+            }
+
             case "darwin": return "ra_lsp_server-mac";
             case "win32":  return "ra_lsp_server-windows.exe";
 
@@ -82,27 +110,26 @@ export class Config {
         }
     }
 
-    private static langServerBinarySource(
-        ctx: vscode.ExtensionContext,
-        config: vscode.WorkspaceConfiguration
-    ): null | BinarySource {
-        const langServerPath = RA_LSP_DEBUG ?? config.get<null | string>("raLspServerPath");
+    get serverSource(): null | BinarySource {
+        const serverPath = RA_LSP_DEBUG ?? this.cfg.get<null | string>("raLspServerPath");
 
-        if (langServerPath) {
+        if (serverPath) {
             return {
                 type: BinarySource.Type.ExplicitPath,
-                path: Config.expandPathResolving(langServerPath)
+                path: Config.replaceTildeWithHomeDir(serverPath)
             };
         }
 
-        const prebuiltBinaryName = Config.prebuiltLangServerFileName(process.platform);
+        const prebuiltBinaryName = this.prebuiltServerFileName;
 
         if (!prebuiltBinaryName) return null;
 
         return {
             type: BinarySource.Type.GithubRelease,
-            dir: ctx.globalStoragePath,
+            dir:  this.ctx.globalStoragePath,
             file: prebuiltBinaryName,
+            storage: this.ctx.globalState,
+            version: Config.extensionVersion,
             repo: {
                 name: "rust-analyzer",
                 owner: "rust-analyzer",
@@ -110,158 +137,36 @@ export class Config {
         };
     }
 
+    // We don't do runtime config validation here for simplicity. More on stackoverflow:
+    // https://stackoverflow.com/questions/60135780/what-is-the-best-way-to-type-check-the-configuration-for-vscode-extension
+
+    get highlightingOn()        { return this.cfg.get("highlightingOn") as boolean; }
+    get rainbowHighlightingOn() { return this.cfg.get("rainbowHighlightingOn") as boolean; }
+    get lruCapacity()           { return this.cfg.get("lruCapacity") as null | number; }
+    get displayInlayHints()     { return this.cfg.get("displayInlayHints") as boolean; }
+    get maxInlayHintLength()    { return this.cfg.get("maxInlayHintLength") as number; }
+    get excludeGlobs()          { return this.cfg.get("excludeGlobs") as string[]; }
+    get useClientWatching()     { return this.cfg.get("useClientWatching") as boolean; }
+    get featureFlags()          { return this.cfg.get("featureFlags") as Record<string, boolean>; }
+    get rustfmtArgs()           { return this.cfg.get("rustfmtArgs") as string[]; }
+    
+    get cargoWatchOptions(): CargoWatchOptions {
+        return {
+            enable:     this.cfg.get("cargo-watch.enable") as boolean,
+            arguments:  this.cfg.get("cargo-watch.arguments") as string[],
+            allTargets: this.cfg.get("cargo-watch.allTargets") as boolean,
+            command:    this.cfg.get("cargo-watch.command") as string,
+        };
+    }
 
-    // FIXME: revisit the logic for `if (.has(...)) config.get(...)` set default
-    // values only in one place (i.e. remove default values from non-readonly members declarations)
-    private refresh(ctx: vscode.ExtensionContext) {
-        const config = vscode.workspace.getConfiguration('rust-analyzer');
-
-        let requireReloadMessage = null;
-
-        if (config.has('highlightingOn')) {
-            this.highlightingOn = config.get('highlightingOn') as boolean;
-        }
-
-        if (config.has('rainbowHighlightingOn')) {
-            this.rainbowHighlightingOn = config.get(
-                'rainbowHighlightingOn',
-            ) as boolean;
-        }
-
-        if (config.has('enableEnhancedTyping')) {
-            this.enableEnhancedTyping = config.get(
-                'enableEnhancedTyping',
-            ) as boolean;
-
-            if (this.prevEnhancedTyping === null) {
-                this.prevEnhancedTyping = this.enableEnhancedTyping;
-            }
-        } else if (this.prevEnhancedTyping === null) {
-            this.prevEnhancedTyping = this.enableEnhancedTyping;
-        }
-
-        if (this.prevEnhancedTyping !== this.enableEnhancedTyping) {
-            requireReloadMessage =
-                'Changing enhanced typing setting requires a reload';
-            this.prevEnhancedTyping = this.enableEnhancedTyping;
-        }
-
-        this.langServerSource = Config.langServerBinarySource(ctx, config);
-
-        if (config.has('cargo-watch.enable')) {
-            this.cargoWatchOptions.enable = config.get<boolean>(
-                'cargo-watch.enable',
-                true,
-            );
-        }
-
-        if (config.has('cargo-watch.arguments')) {
-            this.cargoWatchOptions.arguments = config.get<string[]>(
-                'cargo-watch.arguments',
-                [],
-            );
-        }
-
-        if (config.has('cargo-watch.command')) {
-            this.cargoWatchOptions.command = config.get<string>(
-                'cargo-watch.command',
-                '',
-            );
-        }
-
-        if (config.has('cargo-watch.allTargets')) {
-            this.cargoWatchOptions.allTargets = config.get<boolean>(
-                'cargo-watch.allTargets',
-                true,
-            );
-        }
-
-        if (config.has('lruCapacity')) {
-            this.lruCapacity = config.get('lruCapacity') as number;
-        }
-
-        if (config.has('displayInlayHints')) {
-            this.displayInlayHints = config.get('displayInlayHints') as boolean;
-        }
-        if (config.has('maxInlayHintLength')) {
-            this.maxInlayHintLength = config.get(
-                'maxInlayHintLength',
-            ) as number;
-        }
-        if (config.has('excludeGlobs')) {
-            this.excludeGlobs = config.get('excludeGlobs') || [];
-        }
-        if (config.has('useClientWatching')) {
-            this.useClientWatching = config.get('useClientWatching') || true;
-        }
-        if (config.has('featureFlags')) {
-            this.featureFlags = config.get('featureFlags') || {};
-        }
-        if (config.has('withSysroot')) {
-            this.withSysroot = config.get('withSysroot') || false;
-        }
-
-        if (config.has('cargoFeatures.noDefaultFeatures')) {
-            this.cargoFeatures.noDefaultFeatures = config.get(
-                'cargoFeatures.noDefaultFeatures',
-                false,
-            );
-        }
-        if (config.has('cargoFeatures.allFeatures')) {
-            this.cargoFeatures.allFeatures = config.get(
-                'cargoFeatures.allFeatures',
-                true,
-            );
-        }
-        if (config.has('cargoFeatures.features')) {
-            this.cargoFeatures.features = config.get(
-                'cargoFeatures.features',
-                [],
-            );
-        }
-
-        if (
-            this.prevCargoFeatures !== null &&
-            (this.cargoFeatures.allFeatures !==
-                this.prevCargoFeatures.allFeatures ||
-                this.cargoFeatures.noDefaultFeatures !==
-                this.prevCargoFeatures.noDefaultFeatures ||
-                this.cargoFeatures.features.length !==
-                this.prevCargoFeatures.features.length ||
-                this.cargoFeatures.features.some(
-                    (v, i) => v !== this.prevCargoFeatures!.features[i],
-                ))
-        ) {
-            requireReloadMessage = 'Changing cargo features requires a reload';
-        }
-        this.prevCargoFeatures = { ...this.cargoFeatures };
-
-        if (this.prevCargoWatchOptions !== null) {
-            const changed =
-                this.cargoWatchOptions.enable !== this.prevCargoWatchOptions.enable ||
-                this.cargoWatchOptions.command !== this.prevCargoWatchOptions.command ||
-                this.cargoWatchOptions.allTargets !== this.prevCargoWatchOptions.allTargets ||
-                this.cargoWatchOptions.arguments.length !== this.prevCargoWatchOptions.arguments.length ||
-                this.cargoWatchOptions.arguments.some(
-                    (v, i) => v !== this.prevCargoWatchOptions!.arguments[i],
-                );
-            if (changed) {
-                requireReloadMessage = 'Changing cargo-watch options requires a reload';
-            }
-        }
-        this.prevCargoWatchOptions = { ...this.cargoWatchOptions };
-
-        if (requireReloadMessage !== null) {
-            const reloadAction = 'Reload now';
-            vscode.window
-                .showInformationMessage(requireReloadMessage, reloadAction)
-                .then(selectedAction => {
-                    if (selectedAction === reloadAction) {
-                        vscode.commands.executeCommand(
-                            'workbench.action.reloadWindow',
-                        );
-                    }
-                });
-        }
+    get cargoFeatures(): CargoFeatures {
+        return {
+            noDefaultFeatures: this.cfg.get("cargoFeatures.noDefaultFeatures") as boolean,
+            allFeatures:       this.cfg.get("cargoFeatures.allFeatures") as boolean,
+            features:          this.cfg.get("cargoFeatures.features") as string[],
+        };
     }
+
+    // for internal use
+    get withSysroot() { return this.cfg.get("withSysroot", true) as boolean; }
 }
diff --git a/editors/code/src/ctx.ts b/editors/code/src/ctx.ts
index 70042a479..ff6245f78 100644
--- a/editors/code/src/ctx.ts
+++ b/editors/code/src/ctx.ts
@@ -60,6 +60,10 @@ export class Ctx {
         this.pushCleanup(d);
     }
 
+    get globalState(): vscode.Memento {
+        return this.extCtx.globalState;
+    }
+
     get subscriptions(): Disposable[] {
         return this.extCtx.subscriptions;
     }
@@ -87,15 +91,11 @@ export async function sendRequestWithRetry<R>(
     for (const delay of [2, 4, 6, 8, 10, null]) {
         try {
             return await (token ? client.sendRequest(method, param, token) : client.sendRequest(method, param));
-        } catch (e) {
-            if (
-                e.code === lc.ErrorCodes.ContentModified &&
-                delay !== null
-            ) {
-                await sleep(10 * (1 << delay));
-                continue;
+        } catch (err) {
+            if (delay === null || err.code !== lc.ErrorCodes.ContentModified) {
+                throw err;
             }
-            throw e;
+            await sleep(10 * (1 << delay));
         }
     }
     throw 'unreachable';
diff --git a/editors/code/src/inlay_hints.ts b/editors/code/src/inlay_hints.ts
index 1c019a51b..3896878cd 100644
--- a/editors/code/src/inlay_hints.ts
+++ b/editors/code/src/inlay_hints.ts
@@ -13,7 +13,7 @@ export function activateInlayHints(ctx: Ctx) {
 
     vscode.workspace.onDidChangeTextDocument(
         async event => {
-            if (event.contentChanges.length !== 0) return;
+            if (event.contentChanges.length === 0) return;
             if (event.document.languageId !== 'rust') return;
             await hintsUpdater.refresh();
         },
@@ -27,7 +27,9 @@ export function activateInlayHints(ctx: Ctx) {
         ctx.subscriptions
     );
 
-    ctx.onDidRestart(_ => hintsUpdater.setEnabled(ctx.config.displayInlayHints));
+    // We pass async function though it will not be awaited when called,
+    // thus Promise rejections won't be handled, but this should never throw in fact...
+    ctx.onDidRestart(async _ => hintsUpdater.setEnabled(ctx.config.displayInlayHints));
 }
 
 interface InlayHintsParams {
@@ -36,7 +38,7 @@ interface InlayHintsParams {
 
 interface InlayHint {
     range: vscode.Range;
-    kind: string;
+    kind: "TypeHint" | "ParameterHint";
     label: string;
 }
 
@@ -53,7 +55,7 @@ const parameterHintDecorationType = vscode.window.createTextEditorDecorationType
 });
 
 class HintsUpdater {
-    private pending: Map<string, vscode.CancellationTokenSource> = new Map();
+    private pending = new Map<string, vscode.CancellationTokenSource>();
     private ctx: Ctx;
     private enabled: boolean;
 
@@ -62,30 +64,36 @@ class HintsUpdater {
         this.enabled = ctx.config.displayInlayHints;
     }
 
-    async setEnabled(enabled: boolean) {
+    async setEnabled(enabled: boolean): Promise<void> {
         if (this.enabled == enabled) return;
         this.enabled = enabled;
 
         if (this.enabled) {
-            await this.refresh();
-        } else {
-            this.allEditors.forEach(it => {
-                this.setTypeDecorations(it, []);
-                this.setParameterDecorations(it, []);
-            });
+            return await this.refresh();
         }
+        this.allEditors.forEach(it => {
+            this.setTypeDecorations(it, []);
+            this.setParameterDecorations(it, []);
+        });
     }
 
     async refresh() {
         if (!this.enabled) return;
-        const promises = this.allEditors.map(it => this.refreshEditor(it));
-        await Promise.all(promises);
+        await Promise.all(this.allEditors.map(it => this.refreshEditor(it)));
+    }
+
+    private get allEditors(): vscode.TextEditor[] {
+        return vscode.window.visibleTextEditors.filter(
+            editor => editor.document.languageId === 'rust',
+        );
     }
 
     private async refreshEditor(editor: vscode.TextEditor): Promise<void> {
         const newHints = await this.queryHints(editor.document.uri.toString());
         if (newHints == null) return;
-        const newTypeDecorations = newHints.filter(hint => hint.kind === 'TypeHint')
+
+        const newTypeDecorations = newHints
+            .filter(hint => hint.kind === 'TypeHint')
             .map(hint => ({
                 range: hint.range,
                 renderOptions: {
@@ -96,7 +104,8 @@ class HintsUpdater {
             }));
         this.setTypeDecorations(editor, newTypeDecorations);
 
-        const newParameterDecorations = newHints.filter(hint => hint.kind === 'ParameterHint')
+        const newParameterDecorations = newHints
+            .filter(hint => hint.kind === 'ParameterHint')
             .map(hint => ({
                 range: hint.range,
                 renderOptions: {
@@ -108,12 +117,6 @@ class HintsUpdater {
         this.setParameterDecorations(editor, newParameterDecorations);
     }
 
-    private get allEditors(): vscode.TextEditor[] {
-        return vscode.window.visibleTextEditors.filter(
-            editor => editor.document.languageId === 'rust',
-        );
-    }
-
     private setTypeDecorations(
         editor: vscode.TextEditor,
         decorations: vscode.DecorationOptions[],
@@ -137,12 +140,14 @@ class HintsUpdater {
     private async queryHints(documentUri: string): Promise<InlayHint[] | null> {
         const client = this.ctx.client;
         if (!client) return null;
+
         const request: InlayHintsParams = {
             textDocument: { uri: documentUri },
         };
         const tokenSource = new vscode.CancellationTokenSource();
-        const prev = this.pending.get(documentUri);
-        if (prev) prev.cancel();
+        const prevHintsRequest = this.pending.get(documentUri);
+        prevHintsRequest?.cancel();
+
         this.pending.set(documentUri, tokenSource);
         try {
             return await sendRequestWithRetry<InlayHint[] | null>(
diff --git a/editors/code/src/installation/download_artifact.ts b/editors/code/src/installation/download_artifact.ts
new file mode 100644
index 000000000..de655f8f4
--- /dev/null
+++ b/editors/code/src/installation/download_artifact.ts
@@ -0,0 +1,58 @@
+import * as vscode from "vscode";
+import * as path from "path";
+import { promises as fs } from "fs";
+import { strict as assert } from "assert";
+
+import { ArtifactReleaseInfo } from "./interfaces";
+import { downloadFile } from "./download_file";
+import { throttle } from "throttle-debounce";
+
+/**
+ * Downloads artifact from given `downloadUrl`.
+ * Creates `installationDir` if it is not yet created and put the artifact under
+ * `artifactFileName`.
+ * Displays info about the download progress in an info message printing the name
+ * of the artifact as `displayName`.
+ */
+export async function downloadArtifact(
+    {downloadUrl, releaseName}: ArtifactReleaseInfo,
+    artifactFileName: string,
+    installationDir: string,
+    displayName: string,
+) {
+    await fs.mkdir(installationDir).catch(err => assert.strictEqual(
+        err?.code,
+        "EEXIST",
+        `Couldn't create directory "${installationDir}" to download `+
+        `${artifactFileName} artifact: ${err.message}`
+    ));
+
+    const installationPath = path.join(installationDir, artifactFileName);
+
+    console.time(`Downloading ${artifactFileName}`);
+    await vscode.window.withProgress(
+        {
+            location: vscode.ProgressLocation.Notification,
+            cancellable: false, // FIXME: add support for canceling download?
+            title: `Downloading ${displayName} (${releaseName})`
+        },
+        async (progress, _cancellationToken) => {
+            let lastPrecentage = 0;
+            const filePermissions = 0o755; // (rwx, r_x, r_x)
+            await downloadFile(downloadUrl, installationPath, filePermissions, throttle(
+                200,
+                /* noTrailing: */ true,
+                (readBytes, totalBytes) => {
+                    const newPercentage = (readBytes / totalBytes) * 100;
+                    progress.report({
+                        message: newPercentage.toFixed(0) + "%",
+                        increment: newPercentage - lastPrecentage
+                    });
+
+                    lastPrecentage = newPercentage;
+                })
+            );
+        }
+    );
+    console.timeEnd(`Downloading ${artifactFileName}`);
+}
diff --git a/editors/code/src/installation/download_file.ts b/editors/code/src/installation/download_file.ts
index b51602ef9..d154f4816 100644
--- a/editors/code/src/installation/download_file.ts
+++ b/editors/code/src/installation/download_file.ts
@@ -1,9 +1,13 @@
 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`.
+ * Downloads file from `url` and stores it at `destFilePath` with `destFilePermissions`.
  * `onProgress` callback is called on recieveing each chunk of bytes
  * to track the progress of downloading, it gets the already read and total
  * amount of bytes to read as its parameters.
@@ -11,24 +15,37 @@ import { strict as assert } from "assert";
 export async function downloadFile(
     url: string,
     destFilePath: fs.PathLike,
+    destFilePermissions: number,
     onProgress: (readBytes: number, totalBytes: number) => void
 ): Promise<void> {
-    const response = await fetch(url);
+    const res = await fetch(url);
+
+    if (!res.ok) {
+        console.log("Error", res.status, "while downloading file from", url);
+        console.dir({ body: await res.text(), headers: res.headers }, { depth: 3 });
 
-    const totalBytes = Number(response.headers.get('content-length'));
+        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) => response.body
-        .on("data", (chunk: Buffer) => {
-            readBytes += chunk.length;
-            onProgress(readBytes, totalBytes);
-        })
-        .on("end", resolve)
-        .on("error", reject)
-        .pipe(fs.createWriteStream(destFilePath))
-    );
+        // 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/fetch_latest_artifact_metadata.ts b/editors/code/src/installation/fetch_artifact_release_info.ts
index 7e3700603..7d497057a 100644
--- a/editors/code/src/installation/fetch_latest_artifact_metadata.ts
+++ b/editors/code/src/installation/fetch_artifact_release_info.ts
@@ -1,26 +1,32 @@
 import fetch from "node-fetch";
-import { GithubRepo, ArtifactMetadata } from "./interfaces";
+import { GithubRepo, ArtifactReleaseInfo } from "./interfaces";
 
 const GITHUB_API_ENDPOINT_URL = "https://api.github.com";
 
+
 /**
- * Fetches the latest release from GitHub `repo` and returns metadata about
- * `artifactFileName` shipped with this release or `null` if no such artifact was published.
+ * Fetches the release with `releaseTag` (or just latest release when not specified)
+ * from GitHub `repo` and returns metadata about `artifactFileName` shipped with
+ * this release or `null` if no such artifact was published.
  */
-export async function fetchLatestArtifactMetadata(
-    repo: GithubRepo, artifactFileName: string
-): Promise<null | ArtifactMetadata> {
+export async function fetchArtifactReleaseInfo(
+    repo: GithubRepo, artifactFileName: string, releaseTag?: string
+): Promise<null | ArtifactReleaseInfo> {
 
     const repoOwner = encodeURIComponent(repo.owner);
     const repoName  = encodeURIComponent(repo.name);
 
-    const apiEndpointPath = `/repos/${repoOwner}/${repoName}/releases/latest`;
+    const apiEndpointPath = releaseTag
+        ? `/repos/${repoOwner}/${repoName}/releases/tags/${releaseTag}`
+        : `/repos/${repoOwner}/${repoName}/releases/latest`;
+
     const requestUrl = GITHUB_API_ENDPOINT_URL + apiEndpointPath;
 
     // We skip runtime type checks for simplicity (here we cast from `any` to `GithubRelease`)
 
     console.log("Issuing request for released artifacts metadata to", requestUrl);
 
+    // FIXME: handle non-ok response
     const response: GithubRelease = await fetch(requestUrl, {
             headers: { Accept: "application/vnd.github.v3+json" }
         })
diff --git a/editors/code/src/installation/interfaces.ts b/editors/code/src/installation/interfaces.ts
index 8039d0b90..e40839e4b 100644
--- a/editors/code/src/installation/interfaces.ts
+++ b/editors/code/src/installation/interfaces.ts
@@ -1,3 +1,5 @@
+import * as vscode from "vscode";
+
 export interface GithubRepo {
     name: string;
     owner: string;
@@ -6,7 +8,7 @@ export interface GithubRepo {
 /**
  * Metadata about particular artifact retrieved from GitHub releases.
  */
-export interface ArtifactMetadata {
+export interface ArtifactReleaseInfo {
     releaseName: string;
     downloadUrl: string;
 }
@@ -50,6 +52,17 @@ export namespace BinarySource {
          * and in local `.dir`.
          */
         file: string;
+
+        /**
+         * Tag of github release that denotes a version required by this extension.
+         */
+        version: string;
+
+        /**
+         * Object that provides `get()/update()` operations to store metadata
+         * about the actual binary, e.g. its actual version.
+         */
+        storage: vscode.Memento;
     }
 
 }
diff --git a/editors/code/src/installation/language_server.ts b/editors/code/src/installation/language_server.ts
deleted file mode 100644
index 1ce67b8b2..000000000
--- a/editors/code/src/installation/language_server.ts
+++ /dev/null
@@ -1,141 +0,0 @@
-import * as vscode from "vscode";
-import * as path from "path";
-import { strict as assert } from "assert";
-import { promises as fs } from "fs";
-import { promises as dns } from "dns";
-import { spawnSync } from "child_process";
-import { throttle } from "throttle-debounce";
-
-import { BinarySource } from "./interfaces";
-import { fetchLatestArtifactMetadata } from "./fetch_latest_artifact_metadata";
-import { downloadFile } from "./download_file";
-
-export async function downloadLatestLanguageServer(
-    {file: artifactFileName, dir: installationDir, repo}: BinarySource.GithubRelease
-) {
-    const { releaseName, downloadUrl } = (await fetchLatestArtifactMetadata(
-        repo, artifactFileName
-    ))!;
-
-    await fs.mkdir(installationDir).catch(err => assert.strictEqual(
-        err?.code,
-        "EEXIST",
-        `Couldn't create directory "${installationDir}" to download `+
-        `language server binary: ${err.message}`
-    ));
-
-    const installationPath = path.join(installationDir, artifactFileName);
-
-    console.time("Downloading ra_lsp_server");
-    await vscode.window.withProgress(
-        {
-            location: vscode.ProgressLocation.Notification,
-            cancellable: false, // FIXME: add support for canceling download?
-            title: `Downloading language server (${releaseName})`
-        },
-        async (progress, _cancellationToken) => {
-            let lastPrecentage = 0;
-            await downloadFile(downloadUrl, installationPath, throttle(
-                200,
-                /* noTrailing: */ true,
-                (readBytes, totalBytes) => {
-                    const newPercentage = (readBytes / totalBytes) * 100;
-                    progress.report({
-                        message: newPercentage.toFixed(0) + "%",
-                        increment: newPercentage - lastPrecentage
-                    });
-
-                    lastPrecentage = newPercentage;
-                })
-            );
-        }
-    );
-    console.timeEnd("Downloading ra_lsp_server");
-
-    await fs.chmod(installationPath, 0o755); // Set (rwx, r_x, r_x) permissions
-}
-export async function ensureLanguageServerBinary(
-    langServerSource: null | BinarySource
-): Promise<null | string> {
-
-    if (!langServerSource) {
-        vscode.window.showErrorMessage(
-            "Unfortunately we don't ship binaries for your platform yet. " +
-            "You need to manually clone rust-analyzer repository and " +
-            "run `cargo xtask install --server` to build the language server from sources. " +
-            "If you feel that your platform should be supported, please create an issue " +
-            "about that [here](https://github.com/rust-analyzer/rust-analyzer/issues) and we " +
-            "will consider it."
-        );
-        return null;
-    }
-
-    switch (langServerSource.type) {
-        case BinarySource.Type.ExplicitPath: {
-            if (isBinaryAvailable(langServerSource.path)) {
-                return langServerSource.path;
-            }
-
-            vscode.window.showErrorMessage(
-                `Unable to run ${langServerSource.path} binary. ` +
-                `To use the pre-built language server, set "rust-analyzer.raLspServerPath" ` +
-                "value to `null` or remove it from the settings to use it by default."
-            );
-            return null;
-        }
-        case BinarySource.Type.GithubRelease: {
-            const prebuiltBinaryPath = path.join(langServerSource.dir, langServerSource.file);
-
-            if (isBinaryAvailable(prebuiltBinaryPath)) {
-                return prebuiltBinaryPath;
-            }
-
-            const userResponse = await vscode.window.showInformationMessage(
-                "Language server binary for rust-analyzer was not found. " +
-                "Do you want to download it now?",
-                "Download now", "Cancel"
-            );
-            if (userResponse !== "Download now") return null;
-
-            try {
-                await downloadLatestLanguageServer(langServerSource);
-            } catch (err) {
-                await vscode.window.showErrorMessage(
-                    `Failed to download language server from ${langServerSource.repo.name} ` +
-                    `GitHub repository: ${err.message}`
-                );
-
-                await dns.resolve('www.google.com').catch(err => {
-                    console.error("DNS resolution failed, there might be an issue with Internet availability");
-                    console.error(err);
-                });
-
-                return null;
-            }
-
-            if (!isBinaryAvailable(prebuiltBinaryPath)) assert(false,
-                `Downloaded language server binary is not functional.` +
-                `Downloaded from: ${JSON.stringify(langServerSource)}`
-            );
-
-
-            vscode.window.showInformationMessage(
-                "Rust analyzer language server was successfully installed 🦀"
-            );
-
-            return prebuiltBinaryPath;
-        }
-    }
-
-    function isBinaryAvailable(binaryPath: string) {
-        const res = spawnSync(binaryPath, ["--version"]);
-
-        // ACHTUNG! `res` type declaration is inherently wrong, see
-        // https://github.com/DefinitelyTyped/DefinitelyTyped/issues/42221
-
-        console.log("Checked binary availablity via --version", res);
-        console.log(binaryPath, "--version output:", res.output?.map(String));
-
-        return res.status === 0;
-    }
-}
diff --git a/editors/code/src/installation/server.ts b/editors/code/src/installation/server.ts
new file mode 100644
index 000000000..80cb719e3
--- /dev/null
+++ b/editors/code/src/installation/server.ts
@@ -0,0 +1,124 @@
+import * as vscode from "vscode";
+import * as path from "path";
+import { strict as assert } from "assert";
+import { promises as dns } from "dns";
+import { spawnSync } from "child_process";
+
+import { BinarySource } from "./interfaces";
+import { fetchArtifactReleaseInfo } from "./fetch_artifact_release_info";
+import { downloadArtifact } from "./download_artifact";
+
+export async function ensureServerBinary(source: null | BinarySource): Promise<null | string> {
+    if (!source) {
+        vscode.window.showErrorMessage(
+            "Unfortunately we don't ship binaries for your platform yet. " +
+            "You need to manually clone rust-analyzer repository and " +
+            "run `cargo xtask install --server` to build the language server from sources. " +
+            "If you feel that your platform should be supported, please create an issue " +
+            "about that [here](https://github.com/rust-analyzer/rust-analyzer/issues) and we " +
+            "will consider it."
+        );
+        return null;
+    }
+
+    switch (source.type) {
+        case BinarySource.Type.ExplicitPath: {
+            if (isBinaryAvailable(source.path)) {
+                return source.path;
+            }
+
+            vscode.window.showErrorMessage(
+                `Unable to run ${source.path} binary. ` +
+                `To use the pre-built language server, set "rust-analyzer.raLspServerPath" ` +
+                "value to `null` or remove it from the settings to use it by default."
+            );
+            return null;
+        }
+        case BinarySource.Type.GithubRelease: {
+            const prebuiltBinaryPath = path.join(source.dir, source.file);
+
+            const installedVersion: null | string = getServerVersion(source.storage);
+            const requiredVersion: string = source.version;
+
+            console.log("Installed version:", installedVersion, "required:", requiredVersion);
+
+            if (isBinaryAvailable(prebuiltBinaryPath) && installedVersion == requiredVersion) {
+                // FIXME: check for new releases and notify the user to update if possible
+                return prebuiltBinaryPath;
+            }
+
+            const userResponse = await vscode.window.showInformationMessage(
+                `Language server version ${source.version} for rust-analyzer is not installed. ` +
+                "Do you want to download it now?",
+                "Download now", "Cancel"
+            );
+            if (userResponse !== "Download now") return null;
+
+            if (!await downloadServer(source)) return null;
+
+            return prebuiltBinaryPath;
+        }
+    }
+}
+
+async function downloadServer(source: BinarySource.GithubRelease): Promise<boolean> {
+    try {
+        const releaseInfo = (await fetchArtifactReleaseInfo(source.repo, source.file, source.version))!;
+
+        await downloadArtifact(releaseInfo, source.file, source.dir, "language server");
+        await setServerVersion(source.storage, releaseInfo.releaseName);
+    } catch (err) {
+        vscode.window.showErrorMessage(
+            `Failed to download language server from ${source.repo.name} ` +
+            `GitHub repository: ${err.message}`
+        );
+
+        console.error(err);
+
+        dns.resolve('example.com').then(
+            addrs => console.log("DNS resolution for example.com was successful", addrs),
+            err => {
+                console.error(
+                    "DNS resolution for example.com failed, " +
+                    "there might be an issue with Internet availability"
+                );
+                console.error(err);
+            }
+        );
+        return false;
+    }
+
+    if (!isBinaryAvailable(path.join(source.dir, source.file))) assert(false,
+        `Downloaded language server binary is not functional.` +
+        `Downloaded from: ${JSON.stringify(source, null, 4)}`
+    );
+
+    vscode.window.showInformationMessage(
+        "Rust analyzer language server was successfully installed 🦀"
+    );
+
+    return true;
+}
+
+function isBinaryAvailable(binaryPath: string): boolean {
+    const res = spawnSync(binaryPath, ["--version"]);
+
+    // ACHTUNG! `res` type declaration is inherently wrong, see
+    // https://github.com/DefinitelyTyped/DefinitelyTyped/issues/42221
+
+    console.log("Checked binary availablity via --version", res);
+    console.log(binaryPath, "--version output:", res.output?.map(String));
+
+    return res.status === 0;
+}
+
+function getServerVersion(storage: vscode.Memento): null | string {
+    const version = storage.get<null | string>("server-version", null);
+    console.log("Get server-version:", version);
+    return version;
+}
+
+async function setServerVersion(storage: vscode.Memento, version: string): Promise<void> {
+    console.log("Set server-version:", version);
+    await storage.update("server-version", version.toString());
+}
diff --git a/editors/code/src/status_display.ts b/editors/code/src/status_display.ts
index 51dbf388b..993e79d70 100644
--- a/editors/code/src/status_display.ts
+++ b/editors/code/src/status_display.ts
@@ -66,9 +66,9 @@ class StatusDisplay implements Disposable {
 
     refreshLabel() {
         if (this.packageName) {
-            this.statusBarItem!.text = `${spinnerFrames[this.i]} cargo ${this.command} [${this.packageName}]`;
+            this.statusBarItem.text = `${spinnerFrames[this.i]} cargo ${this.command} [${this.packageName}]`;
         } else {
-            this.statusBarItem!.text = `${spinnerFrames[this.i]} cargo ${this.command}`;
+            this.statusBarItem.text = `${spinnerFrames[this.i]} cargo ${this.command}`;
         }
     }
 
diff --git a/xtask/src/ast_src.rs b/xtask/src/ast_src.rs
index 67d1f41bc..2d9ae904b 100644
--- a/xtask/src/ast_src.rs
+++ b/xtask/src/ast_src.rs
@@ -120,6 +120,8 @@ pub(crate) const KINDS_SRC: KindsSrc = KindsSrc {
         "FOR_TYPE",
         "IMPL_TRAIT_TYPE",
         "DYN_TRAIT_TYPE",
+        "OR_PAT",
+        "PAREN_PAT",
         "REF_PAT",
         "BOX_PAT",
         "BIND_PAT",
@@ -412,26 +414,28 @@ pub(crate) const AST_SRC: AstSrc = AstSrc {
         struct MatchExpr { Expr, MatchArmList }
         struct MatchArmList: AttrsOwner { arms: [MatchArm] }
         struct MatchArm: AttrsOwner {
-            pats: [Pat],
+            pat: Pat,
             guard: MatchGuard,
             Expr,
-         }
+        }
         struct MatchGuard { Expr }
 
         struct RecordLit { Path, RecordFieldList }
         struct RecordFieldList {
             fields: [RecordField],
             spread: Expr,
-         }
+        }
         struct RecordField { NameRef, Expr }
 
+        struct OrPat { pats: [Pat] }
+        struct ParenPat { Pat }
         struct RefPat { Pat }
         struct BoxPat { Pat }
         struct BindPat: NameOwner { Pat }
         struct PlaceholderPat { }
         struct DotDotPat { }
-        struct PathPat {  Path }
-        struct SlicePat {}
+        struct PathPat { Path }
+        struct SlicePat { args: [Pat] }
         struct RangePat {}
         struct LiteralPat { Literal }
 
@@ -601,6 +605,8 @@ pub(crate) const AST_SRC: AstSrc = AstSrc {
         }
 
         enum Pat {
+            OrPat,
+            ParenPat,
             RefPat,
             BoxPat,
             BindPat,
diff --git a/xtask/src/cmd.rs b/xtask/src/cmd.rs
deleted file mode 100644
index 2027f4893..000000000
--- a/xtask/src/cmd.rs
+++ /dev/null
@@ -1,53 +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<Output> {
-        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<Output> {
-    do_run(cmdline, dir, &mut |_| {})
-}
-
-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 8c65b51e3..00bbabce4 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;
@@ -24,6 +24,7 @@ pub struct ServerOpt {
 
 impl InstallCmd {
     pub fn run(self) -> Result<()> {
+        let both = self.server.is_some() && self.client.is_some();
         if cfg!(target_os = "macos") {
             fix_path_for_mac().context("Fix path for mac")?
         }
@@ -33,6 +34,16 @@ impl InstallCmd {
         if let Some(client) = self.client {
             install_client(client).context("install client")?;
         }
+        if both {
+            eprintln!(
+                "
+    Installation complete.
+
+    Add `\"rust-analyzer.raLspServerPath\": \"ra_lsp_server\",` to VS Code settings,
+    otherwise it will use the latest release from GitHub.
+"
+            )
+        }
         Ok(())
     }
 }
@@ -44,7 +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]
@@ -58,7 +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<_>>();
@@ -71,91 +82,63 @@ 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();
+    let _dir = pushd("./editors/code");
 
-    if npm_version.is_err() {
-        eprintln!("\nERROR: `npm --version` failed, `npm` is required to build the VS Code plugin")
-    }
+    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?")
+            })
+    };
 
-    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 installed_extensions;
+    if cfg!(unix) {
+        run!("npm --version").context("`npm` is required to build the VS Code plugin")?;
+        run!("npm install")?;
 
-    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 vsix_pkg = {
+            rm("*.vsix")?;
+            run!("npm run package --scripts-prepend-node-path")?;
+            ls("*.vsix")?.pop().unwrap()
+        };
 
-    let code_binary = match code_binary {
-        Some(it) => it,
-        None => anyhow::bail!("Can't execute `code --version`. Perhaps it is not in $PATH?"),
-    };
+        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()
+        };
 
-    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",
+        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()?;
-
-    let installed_extensions = {
-        let output = Cmd {
-            unix: &format!(r"{} --list-extensions", code_binary),
-            windows: &format!(r"cmd.exe /c {}.cmd --list-extensions", code_binary),
-            work_dir: ".",
-        }
-        .run_with_output()?;
-        String::from_utf8(output.stdout)?
-    };
 
     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."
+             Please make sure you have at least NodeJS 12.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(output) = run_with_output("cargo --version", ".") {
-        if let Ok(stdout) = String::from_utf8(output.stdout) {
-            println!("{}", stdout);
-            if !check_version(&stdout, REQUIRED_RUST_VERSION) {
-                old_rust = true;
-            }
+    if let Ok(stdout) = run!("cargo --version") {
+        if !check_version(&stdout, REQUIRED_RUST_VERSION) {
+            old_rust = true;
         }
     }
 
@@ -166,20 +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 8fdf43e4a..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;
 
@@ -9,13 +9,16 @@ mod ast_src;
 
 use anyhow::Context;
 use std::{
-    env, fs,
+    env,
     io::Write,
     path::{Path, PathBuf},
     process::{Command, Stdio},
 };
 
-use crate::{cmd::run, codegen::Mode};
+use crate::{
+    codegen::Mode,
+    not_bash::{fs2, pushd, rm_rf, run},
+};
 
 pub use anyhow::Result;
 
@@ -35,9 +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(())
 }
@@ -67,8 +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<()> {
@@ -89,34 +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
@@ -138,7 +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()? {
@@ -152,7 +150,45 @@ 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(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 website_root = project_root().join("../rust-analyzer.github.io");
+    let changelog_dir = website_root.join("./thisweek/_posts");
+
+    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!(
+        "\
+= Changelog #{}
+:sectanchors:
+:page-layout: post
+
+Commit: commit:{}[] +
+Release: release:{}[]
+
+== New Features
+
+* pr:[] .
+
+== Fixes
+
+== Internal Improvements
+",
+        changelog_n, commit, today
+    );
+
+    let path = changelog_dir.join(format!("{}-changelog-{}.adoc", today, changelog_n));
+    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 c347de9ab..a7dffe2cc 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -14,7 +14,7 @@ use pico_args::Arguments;
 use xtask::{
     codegen::{self, Mode},
     install::{ClientOpt, InstallCmd, ServerOpt},
-    pre_commit, run_clippy, run_fuzzer, run_pre_cache, run_rustfmt, Result,
+    pre_commit, run_clippy, run_fuzzer, run_pre_cache, run_release, run_rustfmt, Result,
 };
 
 fn main() -> Result<()> {
@@ -92,6 +92,11 @@ FLAGS:
             args.finish()?;
             run_pre_cache()
         }
+        "release" => {
+            let dry_run = args.contains("--dry-run");
+            args.finish()?;
+            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 88e868ca6..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 String::from_utf8(diff.stdout)?.lines() {
-        run(&format!("git update-index --add {}", root.join(line).to_string_lossy()), ".")?;
+    for line in diff.lines() {
+        run!("git update-index --add {}", root.join(line).display())?;
     }
 
     Ok(())