40 files changed, 703 insertions, 128 deletions
diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index 04e2be390..0132565e4 100644
--- a/crates/base_db/src/fixture.rs
+++ b/crates/base_db/src/fixture.rs
@@ -35,7 +35,7 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
    fn with_position(ra_fixture: &str) -> (Self, FilePosition) {
        let (db, file_id, range_or_offset) = Self::with_range_or_offset(ra_fixture);
        let offset = match range_or_offset {
-            RangeOrOffset::Range(_) => panic!(),
+            RangeOrOffset::Range(_) => panic!("Expected a cursor position, got a range instead"),
            RangeOrOffset::Offset(it) => it,
        };
        (db, FilePosition { file_id, offset })
@@ -45,7 +45,7 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
        let (db, file_id, range_or_offset) = Self::with_range_or_offset(ra_fixture);
        let range = match range_or_offset {
            RangeOrOffset::Range(it) => it,
-            RangeOrOffset::Offset(_) => panic!(),
+            RangeOrOffset::Offset(_) => panic!("Expected a cursor range, got a position instead"),
        };
        (db, FileRange { file_id, range })
    }
@@ -54,7 +54,9 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
        let fixture = ChangeFixture::parse(ra_fixture);
        let mut db = Self::default();
        fixture.change.apply(&mut db);
-        let (file_id, range_or_offset) = fixture.file_position.unwrap();
+        let (file_id, range_or_offset) = fixture
+            .file_position
+            .expect("Could not find file position in fixture. Did you forget to add an `$0`?");
        (db, file_id, range_or_offset)
    }
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index eba46a056..0acfa582a 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -2066,6 +2066,18 @@ impl Type {
        self.ty.dyn_trait().map(Into::into)
    }
+    /// If a type can be represented as `dyn Trait`, returns all traits accessible via this type,
+    /// or an empty iterator otherwise.
+    pub fn applicable_inherent_traits<'a>(
+        &'a self,
+        db: &'a dyn HirDatabase,
+    ) -> impl Iterator<Item = Trait> + 'a {
+        self.autoderef(db)
+            .filter_map(|derefed_type| derefed_type.ty.dyn_trait())
+            .flat_map(move |dyn_trait_id| hir_ty::all_super_traits(db.upcast(), dyn_trait_id))
+            .map(Trait::from)
+    }
    pub fn as_impl_traits(&self, db: &dyn HirDatabase) -> Option<Vec<Trait>> {
        self.ty.impl_trait_bounds(db).map(|it| {
            it.into_iter()
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index ed07d6928..c0b0b7841 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -568,9 +568,13 @@ impl ExprCollector<'_> {
        let res = match res {
            Ok(res) => res,
-            Err(UnresolvedMacro) => {
+            Err(UnresolvedMacro { path }) => {
                self.source_map.diagnostics.push(BodyDiagnostic::UnresolvedMacroCall(
-                    UnresolvedMacroCall { file: outer_file, node: syntax_ptr.cast().unwrap() },
+                    UnresolvedMacroCall {
+                        file: outer_file,
+                        node: syntax_ptr.cast().unwrap(),
+                        path,
+                    },
                ));
                collector(self, None);
                return;
diff --git a/crates/hir_def/src/body/tests.rs b/crates/hir_def/src/body/tests.rs
index c1d3e998f..63f5fe88d 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -180,7 +180,7 @@ fn unresolved_macro_diag() {
        r#"
 fn f() {
    m!();
-  //^^^^ unresolved macro call
+  //^^^^ unresolved macro `m!`
 }
      "#,
    );
diff --git a/crates/hir_def/src/diagnostics.rs b/crates/hir_def/src/diagnostics.rs
index 97abf8653..a71ae2668 100644
--- a/crates/hir_def/src/diagnostics.rs
+++ b/crates/hir_def/src/diagnostics.rs
@@ -8,7 +8,7 @@ use hir_expand::diagnostics::{Diagnostic, DiagnosticCode, DiagnosticSink};
 use hir_expand::{HirFileId, InFile};
 use syntax::{ast, AstPtr, SyntaxNodePtr, TextRange};
-use crate::{db::DefDatabase, DefWithBodyId};
+use crate::{db::DefDatabase, path::ModPath, DefWithBodyId};
 pub fn validate_body(db: &dyn DefDatabase, owner: DefWithBodyId, sink: &mut DiagnosticSink<'_>) {
    let source_map = db.body_with_source_map(owner).1;
@@ -103,6 +103,7 @@ impl Diagnostic for UnresolvedImport {
 pub struct UnresolvedMacroCall {
    pub file: HirFileId,
    pub node: AstPtr<ast::MacroCall>,
+    pub path: ModPath,
 }
 impl Diagnostic for UnresolvedMacroCall {
@@ -110,7 +111,7 @@ impl Diagnostic for UnresolvedMacroCall {
        DiagnosticCode("unresolved-macro-call")
    }
    fn message(&self) -> String {
-        "unresolved macro call".to_string()
+        format!("unresolved macro `{}!`", self.path)
    }
    fn display_source(&self) -> InFile<SyntaxNodePtr> {
        InFile::new(self.file, self.node.clone().into())
diff --git a/crates/hir_def/src/find_path.rs b/crates/hir_def/src/find_path.rs
index 41da3bc2d..2c4bbe585 100644
--- a/crates/hir_def/src/find_path.rs
+++ b/crates/hir_def/src/find_path.rs
@@ -955,6 +955,29 @@ fn main() {
    }
    #[test]
+    fn from_inside_module() {
+        // This worked correctly, but the test suite logic was broken.
+        cov_mark::check!(submodule_in_testdb);
+        check_found_path(
+            r#"
+mod baz {
+    pub struct Foo {}
+}
+mod bar {
+    fn bar() {
+        $0
+    }
+}
+            "#,
+            "crate::baz::Foo",
+            "crate::baz::Foo",
+            "crate::baz::Foo",
+            "crate::baz::Foo",
+        )
+    }
+    #[test]
    fn recursive_pub_mod_reexport() {
        cov_mark::check!(recursive_imports);
        check_found_path(
diff --git a/crates/hir_def/src/lib.rs b/crates/hir_def/src/lib.rs
index ffee05500..5ac1670b5 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -66,6 +66,7 @@ use hir_expand::{
 };
 use la_arena::Idx;
 use nameres::DefMap;
+use path::ModPath;
 use syntax::ast;
 use crate::builtin_type::BuiltinType;
@@ -107,6 +108,18 @@ impl ModuleId {
    pub fn containing_module(&self, db: &dyn db::DefDatabase) -> Option<ModuleId> {
        self.def_map(db).containing_module(self.local_id)
    }
+    /// Returns `true` if this module represents a block expression.
+    ///
+    /// Returns `false` if this module is a submodule *inside* a block expression
+    /// (eg. `m` in `{ mod m {} }`).
+    pub fn is_block_root(&self, db: &dyn db::DefDatabase) -> bool {
+        if self.block.is_none() {
+            return false;
+        }
+        self.def_map(db)[self.local_id].parent.is_none()
+    }
 }
 /// An ID of a module, **local** to a specific crate
@@ -675,7 +688,9 @@ impl<T: ast::AstNode> AstIdWithPath<T> {
    }
 }
-pub struct UnresolvedMacro;
+pub struct UnresolvedMacro {
+    pub path: ModPath,
+}
 fn macro_call_as_call_id(
    call: &AstIdWithPath<ast::MacroCall>,
@@ -684,7 +699,8 @@ fn macro_call_as_call_id(
    resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
    error_sink: &mut dyn FnMut(mbe::ExpandError),
 ) -> Result<Result<MacroCallId, ErrorEmitted>, UnresolvedMacro> {
-    let def: MacroDefId = resolver(call.path.clone()).ok_or(UnresolvedMacro)?;
+    let def: MacroDefId =
+        resolver(call.path.clone()).ok_or_else(|| UnresolvedMacro { path: call.path.clone() })?;
    let res = if let MacroDefKind::BuiltInEager(..) = def.kind {
        let macro_call = InFile::new(call.ast_id.file_id, call.ast_id.to_node(db.upcast()));
@@ -714,8 +730,13 @@ fn derive_macro_as_call_id(
    krate: CrateId,
    resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
 ) -> Result<MacroCallId, UnresolvedMacro> {
-    let def: MacroDefId = resolver(item_attr.path.clone()).ok_or(UnresolvedMacro)?;
+    let def: MacroDefId = resolver(item_attr.path.clone())
-    let last_segment = item_attr.path.segments().last().ok_or(UnresolvedMacro)?;
+        .ok_or_else(|| UnresolvedMacro { path: item_attr.path.clone() })?;
+    let last_segment = item_attr
+        .path
+        .segments()
+        .last()
+        .ok_or_else(|| UnresolvedMacro { path: item_attr.path.clone() })?;
    let res = def
        .as_lazy_macro(
            db.upcast(),
diff --git a/crates/hir_def/src/nameres.rs b/crates/hir_def/src/nameres.rs
index 9e181751c..542f190a1 100644
--- a/crates/hir_def/src/nameres.rs
+++ b/crates/hir_def/src/nameres.rs
@@ -481,7 +481,7 @@ mod diagnostics {
        UnresolvedProcMacro { ast: MacroCallKind },
-        UnresolvedMacroCall { ast: AstId<ast::MacroCall> },
+        UnresolvedMacroCall { ast: AstId<ast::MacroCall>, path: ModPath },
        MacroError { ast: MacroCallKind, message: String },
    }
@@ -546,8 +546,9 @@ mod diagnostics {
        pub(super) fn unresolved_macro_call(
            container: LocalModuleId,
            ast: AstId<ast::MacroCall>,
+            path: ModPath,
        ) -> Self {
-            Self { in_module: container, kind: DiagnosticKind::UnresolvedMacroCall { ast } }
+            Self { in_module: container, kind: DiagnosticKind::UnresolvedMacroCall { ast, path } }
        }
        pub(super) fn add_to(
@@ -662,9 +663,13 @@ mod diagnostics {
                    });
                }
-                DiagnosticKind::UnresolvedMacroCall { ast } => {
+                DiagnosticKind::UnresolvedMacroCall { ast, path } => {
                    let node = ast.to_node(db.upcast());
-                    sink.push(UnresolvedMacroCall { file: ast.file_id, node: AstPtr::new(&node) });
+                    sink.push(UnresolvedMacroCall {
+                        file: ast.file_id,
+                        node: AstPtr::new(&node),
+                        path: path.clone(),
+                    });
                }
                DiagnosticKind::MacroError { ast, message } => {
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index fb4ddff5e..05ceb1efb 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -829,7 +829,7 @@ impl DefCollector<'_> {
                            res = ReachedFixedPoint::No;
                            return false;
                        }
-                        Err(UnresolvedMacro) | Ok(Err(_)) => {}
+                        Err(UnresolvedMacro { .. }) | Ok(Err(_)) => {}
                    }
                }
                MacroDirectiveKind::Derive { ast_id, derive_attr } => {
@@ -845,7 +845,7 @@ impl DefCollector<'_> {
                            res = ReachedFixedPoint::No;
                            return false;
                        }
-                        Err(UnresolvedMacro) => (),
+                        Err(UnresolvedMacro { .. }) => (),
                    }
                }
            }
@@ -943,10 +943,11 @@ impl DefCollector<'_> {
                    &mut |_| (),
                ) {
                    Ok(_) => (),
-                    Err(UnresolvedMacro) => {
+                    Err(UnresolvedMacro { path }) => {
                        self.def_map.diagnostics.push(DefDiagnostic::unresolved_macro_call(
                            directive.module_id,
                            ast_id.ast_id,
+                            path,
                        ));
                    }
                },
@@ -1530,7 +1531,7 @@ impl ModCollector<'_, '_> {
                ));
                return;
            }
-            Err(UnresolvedMacro) => (),
+            Err(UnresolvedMacro { .. }) => (),
        }
        // Case 2: resolve in module scope, expand during name resolution.
diff --git a/crates/hir_def/src/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index ccc9f22eb..c984148c3 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -387,7 +387,13 @@ impl DefMap {
            .get_legacy_macro(name)
            .map_or_else(PerNs::none, |m| PerNs::macros(m, Visibility::Public));
        let from_scope = self[module].scope.get(name);
-        let from_builtin = BUILTIN_SCOPE.get(name).copied().unwrap_or_else(PerNs::none);
+        let from_builtin = match self.block {
+            Some(_) => {
+                // Only resolve to builtins in the root `DefMap`.
+                PerNs::none()
+            }
+            None => BUILTIN_SCOPE.get(name).copied().unwrap_or_else(PerNs::none),
+        };
        let from_scope_or_builtin = match shadow {
            BuiltinShadowMode::Module => from_scope.or(from_builtin),
            BuiltinShadowMode::Other => {
diff --git a/crates/hir_def/src/nameres/tests/diagnostics.rs b/crates/hir_def/src/nameres/tests/diagnostics.rs
index 1ac88fc89..543975e07 100644
--- a/crates/hir_def/src/nameres/tests/diagnostics.rs
+++ b/crates/hir_def/src/nameres/tests/diagnostics.rs
@@ -170,7 +170,7 @@ fn unresolved_legacy_scope_macro() {
          m!();
          m2!();
-        //^^^^^^ unresolved macro call
+        //^^^^^^ unresolved macro `self::m2!`
        "#,
    );
 }
@@ -187,7 +187,7 @@ fn unresolved_module_scope_macro() {
          self::m!();
          self::m2!();
-        //^^^^^^^^^^^^ unresolved macro call
+        //^^^^^^^^^^^^ unresolved macro `self::m2!`
        "#,
    );
 }
diff --git a/crates/hir_def/src/test_db.rs b/crates/hir_def/src/test_db.rs
index dd36106f8..8fa703a57 100644
--- a/crates/hir_def/src/test_db.rs
+++ b/crates/hir_def/src/test_db.rs
@@ -15,7 +15,12 @@ use rustc_hash::FxHashSet;
 use syntax::{algo, ast, AstNode, TextRange, TextSize};
 use test_utils::extract_annotations;
-use crate::{db::DefDatabase, nameres::DefMap, src::HasSource, Lookup, ModuleDefId, ModuleId};
+use crate::{
+    db::DefDatabase,
+    nameres::{DefMap, ModuleSource},
+    src::HasSource,
+    LocalModuleId, Lookup, ModuleDefId, ModuleId,
+};
 #[salsa::database(
    base_db::SourceDatabaseExtStorage,
@@ -87,10 +92,11 @@ impl TestDB {
    pub(crate) fn module_at_position(&self, position: FilePosition) -> ModuleId {
        let file_module = self.module_for_file(position.file_id);
        let mut def_map = file_module.def_map(self);
+        let module = self.mod_at_position(&def_map, position);
        def_map = match self.block_at_position(&def_map, position) {
            Some(it) => it,
-            None => return file_module,
+            None => return def_map.module_id(module),
        };
        loop {
            let new_map = self.block_at_position(&def_map, position);
@@ -106,6 +112,47 @@ impl TestDB {
        }
    }
+    /// Finds the smallest/innermost module in `def_map` containing `position`.
+    fn mod_at_position(&self, def_map: &DefMap, position: FilePosition) -> LocalModuleId {
+        let mut size = None;
+        let mut res = def_map.root();
+        for (module, data) in def_map.modules() {
+            let src = data.definition_source(self);
+            if src.file_id != position.file_id.into() {
+                continue;
+            }
+            let range = match src.value {
+                ModuleSource::SourceFile(it) => it.syntax().text_range(),
+                ModuleSource::Module(it) => it.syntax().text_range(),
+                ModuleSource::BlockExpr(it) => it.syntax().text_range(),
+            };
+            if !range.contains(position.offset) {
+                continue;
+            }
+            let new_size = match size {
+                None => range.len(),
+                Some(size) => {
+                    if range.len() < size {
+                        range.len()
+                    } else {
+                        size
+                    }
+                }
+            };
+            if size != Some(new_size) {
+                cov_mark::hit!(submodule_in_testdb);
+                size = Some(new_size);
+                res = module;
+            }
+        }
+        res
+    }
    fn block_at_position(&self, def_map: &DefMap, position: FilePosition) -> Option<Arc<DefMap>> {
        // Find the smallest (innermost) function in `def_map` containing the cursor.
        let mut size = None;
diff --git a/crates/hir_def/src/visibility.rs b/crates/hir_def/src/visibility.rs
index 9908cd926..d4b7c9970 100644
--- a/crates/hir_def/src/visibility.rs
+++ b/crates/hir_def/src/visibility.rs
@@ -123,11 +123,19 @@ impl Visibility {
        def_map: &DefMap,
        mut from_module: crate::LocalModuleId,
    ) -> bool {
-        let to_module = match self {
+        let mut to_module = match self {
            Visibility::Module(m) => m,
            Visibility::Public => return true,
        };
+        // `to_module` might be the root module of a block expression. Those have the same
+        // visibility as the containing module (even though no items are directly nameable from
+        // there, getting this right is important for method resolution).
+        // In that case, we adjust the visibility of `to_module` to point to the containing module.
+        if to_module.is_block_root(db) {
+            to_module = to_module.containing_module(db).unwrap();
+        }
        // from_module needs to be a descendant of to_module
        let mut def_map = def_map;
        let mut parent_arc;
diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index 80365fc16..179de61f9 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -110,6 +110,7 @@ register_builtin! {
    (format_args_nl, FormatArgsNl) => format_args_expand,
    (llvm_asm, LlvmAsm) => asm_expand,
    (asm, Asm) => asm_expand,
+    (global_asm, GlobalAsm) => global_asm_expand,
    (cfg, Cfg) => cfg_expand,
    (core_panic, CorePanic) => panic_expand,
    (std_panic, StdPanic) => panic_expand,
@@ -274,6 +275,15 @@ fn asm_expand(
    ExpandResult::ok(expanded)
 }
+fn global_asm_expand(
+    _db: &dyn AstDatabase,
+    _id: LazyMacroId,
+    _tt: &tt::Subtree,
+) -> ExpandResult<tt::Subtree> {
+    // Expand to nothing (at item-level)
+    ExpandResult::ok(quote! {})
+}
 fn cfg_expand(
    db: &dyn AstDatabase,
    id: LazyMacroId,
diff --git a/crates/hir_expand/src/name.rs b/crates/hir_expand/src/name.rs
index a0f8766b0..bcfd3e524 100644
--- a/crates/hir_expand/src/name.rs
+++ b/crates/hir_expand/src/name.rs
@@ -221,6 +221,7 @@ pub mod known {
        option_env,
        llvm_asm,
        asm,
+        global_asm,
        // Builtin derives
        Copy,
        Clone,
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 113234fa4..0505fa4ae 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -56,6 +56,7 @@ pub use mapping::{
    to_foreign_def_id, to_placeholder_idx,
 };
 pub use traits::TraitEnvironment;
+pub use utils::all_super_traits;
 pub use walk::TypeWalk;
 pub use chalk_ir::{
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index 3693e3284..48bbcfd9f 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -246,29 +246,39 @@ pub struct InherentImpls {
 impl InherentImpls {
    pub(crate) fn inherent_impls_in_crate_query(db: &dyn HirDatabase, krate: CrateId) -> Arc<Self> {
-        let mut map: FxHashMap<_, Vec<_>> = FxHashMap::default();
+        let mut impls = Self { map: FxHashMap::default() };
        let crate_def_map = db.crate_def_map(krate);
-        for (_module_id, module_data) in crate_def_map.modules() {
+        collect_def_map(db, &crate_def_map, &mut impls);
-            for impl_id in module_data.scope.impls() {
-                let data = db.impl_data(impl_id);
+        return Arc::new(impls);
-                if data.target_trait.is_some() {
-                    continue;
+        fn collect_def_map(db: &dyn HirDatabase, def_map: &DefMap, impls: &mut InherentImpls) {
+            for (_module_id, module_data) in def_map.modules() {
+                for impl_id in module_data.scope.impls() {
+                    let data = db.impl_data(impl_id);
+                    if data.target_trait.is_some() {
+                        continue;
+                    }
+                    let self_ty = db.impl_self_ty(impl_id);
+                    let fp = TyFingerprint::for_inherent_impl(self_ty.skip_binders());
+                    if let Some(fp) = fp {
+                        impls.map.entry(fp).or_default().push(impl_id);
+                    }
+                    // `fp` should only be `None` in error cases (either erroneous code or incomplete name resolution)
                }
-                let self_ty = db.impl_self_ty(impl_id);
+                // To better support custom derives, collect impls in all unnamed const items.
-                let fp = TyFingerprint::for_inherent_impl(self_ty.skip_binders());
+                // const _: () = { ... };
-                if let Some(fp) = fp {
+                for konst in module_data.scope.unnamed_consts() {
-                    map.entry(fp).or_default().push(impl_id);
+                    let body = db.body(konst.into());
+                    for (_, block_def_map) in body.blocks(db.upcast()) {
+                        collect_def_map(db, &block_def_map, impls);
+                    }
                }
-                // `fp` should only be `None` in error cases (either erroneous code or incomplete name resolution)
            }
        }
-        // NOTE: We're not collecting inherent impls from unnamed consts here, we intentionally only
-        // support trait impls there.
-        Arc::new(Self { map })
    }
    pub fn for_self_ty(&self, self_ty: &Ty) -> &[ImplId] {
diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index 4b2c82b41..a4c132bc5 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -1294,7 +1294,7 @@ mod b {
 }
 #[test]
-fn impl_in_unnamed_const() {
+fn trait_impl_in_unnamed_const() {
    check_types(
        r#"
 struct S;
@@ -1314,3 +1314,38 @@ fn f() {
    "#,
    );
 }
+#[test]
+fn inherent_impl_in_unnamed_const() {
+    check_types(
+        r#"
+struct S;
+const _: () = {
+    impl S {
+        fn method(&self) -> u16 { 0 }
+        pub(super) fn super_method(&self) -> u16 { 0 }
+        pub(crate) fn crate_method(&self) -> u16 { 0 }
+        pub fn pub_method(&self) -> u16 { 0 }
+    }
+};
+fn f() {
+    S.method();
+  //^^^^^^^^^^ u16
+    S.super_method();
+  //^^^^^^^^^^^^^^^^ u16
+    S.crate_method();
+  //^^^^^^^^^^^^^^^^ u16
+    S.pub_method();
+  //^^^^^^^^^^^^^^ u16
+}
+    "#,
+    );
+}
diff --git a/crates/hir_ty/src/tests/simple.rs b/crates/hir_ty/src/tests/simple.rs
index 84c5c05fd..5948d0bc2 100644
--- a/crates/hir_ty/src/tests/simple.rs
+++ b/crates/hir_ty/src/tests/simple.rs
@@ -1765,6 +1765,24 @@ fn main() {
 }
 #[test]
+fn shadowing_primitive_with_inner_items() {
+    check_types(
+        r#"
+struct i32;
+struct Foo;
+impl i32 { fn foo(&self) -> Foo { Foo } }
+fn main() {
+    fn inner() {}
+    let x: i32 = i32;
+    x.foo();
+        //^ Foo
+}"#,
+    );
+}
+#[test]
 fn not_shadowing_primitive_by_module() {
    check_types(
        r#"
diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs
index 5f6cb052a..2f04ee57a 100644
--- a/crates/hir_ty/src/utils.rs
+++ b/crates/hir_ty/src/utils.rs
@@ -78,7 +78,7 @@ fn direct_super_trait_refs(db: &dyn HirDatabase, trait_ref: &TraitRef) -> Vec<Tr
 /// Returns an iterator over the whole super trait hierarchy (including the
 /// trait itself).
-pub(super) fn all_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
+pub fn all_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
    // we need to take care a bit here to avoid infinite loops in case of cycles
    // (i.e. if we have `trait A: B; trait B: A;`)
    let mut result = vec![trait_];
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index 9a883acb9..1c911a8b2 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -725,7 +725,7 @@ fn test_fn() {
            expect![[r#"
                [
                    Diagnostic {
-                        message: "unresolved macro call",
+                        message: "unresolved macro `foo::bar!`",
                        range: 5..8,
                        severity: Error,
                        fix: None,
diff --git a/crates/ide/src/syntax_highlighting/inject.rs b/crates/ide/src/syntax_highlighting/inject.rs
index 04fafd244..855c7fba8 100644
--- a/crates/ide/src/syntax_highlighting/inject.rs
+++ b/crates/ide/src/syntax_highlighting/inject.rs
@@ -90,6 +90,13 @@ const RUSTDOC_FENCE_TOKENS: &[&'static str] = &[
    "edition2021",
 ];
+fn is_rustdoc_fence_token(token: &str) -> bool {
+    if RUSTDOC_FENCE_TOKENS.contains(&token) {
+        return true;
+    }
+    token.starts_with('E') && token.len() == 5 && token[1..].parse::<u32>().is_ok()
+}
 /// Injection of syntax highlighting of doctests.
 pub(super) fn doc_comment(
    hl: &mut Highlights,
@@ -174,8 +181,7 @@ pub(super) fn doc_comment(
                    is_codeblock = !is_codeblock;
                    // Check whether code is rust by inspecting fence guards
                    let guards = &line[idx + RUSTDOC_FENCE.len()..];
-                    let is_rust =
+                    let is_rust = guards.split(',').all(|sub| is_rustdoc_fence_token(sub.trim()));
-                        guards.split(',').all(|sub| RUSTDOC_FENCE_TOKENS.contains(&sub.trim()));
                    is_doctest = is_codeblock && is_rust;
                    continue;
                }
diff --git a/crates/ide_assists/src/handlers/fill_match_arms.rs b/crates/ide_assists/src/handlers/fill_match_arms.rs
index 878b3a3fa..80bd1b7e8 100644
--- a/crates/ide_assists/src/handlers/fill_match_arms.rs
+++ b/crates/ide_assists/src/handlers/fill_match_arms.rs
@@ -71,12 +71,6 @@ pub(crate) fn fill_match_arms(acc: &mut Assists, ctx: &AssistContext) -> Option<
            return None;
        }
-        // We do not currently support filling match arms for a tuple
-        // containing a single enum.
-        if enum_defs.len() < 2 {
-            return None;
-        }
        // When calculating the match arms for a tuple of enums, we want
        // to create a match arm for each possible combination of enum
        // values. The `multi_cartesian_product` method transforms
@@ -514,10 +508,7 @@ fn main() {
    #[test]
    fn fill_match_arms_single_element_tuple_of_enum() {
-        // For now we don't hande the case of a single element tuple, but
+        check_assist(
-        // we could handle this in the future if `make::tuple_pat` allowed
-        // creating a tuple with a single pattern.
-        check_assist_not_applicable(
            fill_match_arms,
            r#"
            enum A { One, Two }
@@ -528,6 +519,17 @@ fn main() {
                }
            }
            "#,
+            r#"
+            enum A { One, Two }
+            fn main() {
+                let a = A::One;
+                match (a, ) {
+                    $0(A::One,) => {}
+                    (A::Two,) => {}
+                }
+            }
+            "#,
        );
    }
diff --git a/crates/ide_assists/src/handlers/generate_deref.rs b/crates/ide_assists/src/handlers/generate_deref.rs
new file mode 100644
index 000000000..4998ff7a4
--- /dev/null
+++ b/crates/ide_assists/src/handlers/generate_deref.rs
@@ -0,0 +1,227 @@
+use std::fmt::Display;
+use ide_db::{helpers::FamousDefs, RootDatabase};
+use syntax::{
+    ast::{self, NameOwner},
+    AstNode, SyntaxNode,
+};
+use crate::{
+    assist_context::{AssistBuilder, AssistContext, Assists},
+    utils::generate_trait_impl_text,
+    AssistId, AssistKind,
+};
+// Assist: generate_deref
+//
+// Generate `Deref` impl using the given struct field.
+//
+// ```
+// struct A;
+// struct B {
+//    $0a: A
+// }
+// ```
+// ->
+// ```
+// struct A;
+// struct B {
+//    a: A
+// }
+//
+// impl std::ops::Deref for B {
+//     type Target = A;
+//
+//     fn deref(&self) -> &Self::Target {
+//         &self.a
+//     }
+// }
+// ```
+pub(crate) fn generate_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    generate_record_deref(acc, ctx).or_else(|| generate_tuple_deref(acc, ctx))
+}
+fn generate_record_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+    if existing_deref_impl(&ctx.sema, &strukt).is_some() {
+        cov_mark::hit!(test_add_record_deref_impl_already_exists);
+        return None;
+    }
+    let field_type = field.ty()?;
+    let field_name = field.name()?;
+    let target = field.syntax().text_range();
+    acc.add(
+        AssistId("generate_deref", AssistKind::Generate),
+        format!("Generate `Deref` impl using `{}`", field_name),
+        target,
+        |edit| generate_edit(edit, strukt, field_type.syntax(), field_name.syntax()),
+    )
+}
+fn generate_tuple_deref(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::TupleField>()?;
+    let field_list = ctx.find_node_at_offset::<ast::TupleFieldList>()?;
+    let field_list_index =
+        field_list.syntax().children().into_iter().position(|s| &s == field.syntax())?;
+    if existing_deref_impl(&ctx.sema, &strukt).is_some() {
+        cov_mark::hit!(test_add_field_deref_impl_already_exists);
+        return None;
+    }
+    let field_type = field.ty()?;
+    let target = field.syntax().text_range();
+    acc.add(
+        AssistId("generate_deref", AssistKind::Generate),
+        format!("Generate `Deref` impl using `{}`", field.syntax()),
+        target,
+        |edit| generate_edit(edit, strukt, field_type.syntax(), field_list_index),
+    )
+}
+fn generate_edit(
+    edit: &mut AssistBuilder,
+    strukt: ast::Struct,
+    field_type_syntax: &SyntaxNode,
+    field_name: impl Display,
+) {
+    let start_offset = strukt.syntax().text_range().end();
+    let impl_code = format!(
+        r#"    type Target = {0};
+    fn deref(&self) -> &Self::Target {{
+        &self.{1}
+    }}"#,
+        field_type_syntax, field_name
+    );
+    let strukt_adt = ast::Adt::Struct(strukt);
+    let deref_impl = generate_trait_impl_text(&strukt_adt, "std::ops::Deref", &impl_code);
+    edit.insert(start_offset, deref_impl);
+}
+fn existing_deref_impl(
+    sema: &'_ hir::Semantics<'_, RootDatabase>,
+    strukt: &ast::Struct,
+) -> Option<()> {
+    let strukt = sema.to_def(strukt)?;
+    let krate = strukt.module(sema.db).krate();
+    let deref_trait = FamousDefs(sema, Some(krate)).core_ops_Deref()?;
+    let strukt_type = strukt.ty(sema.db);
+    if strukt_type.impls_trait(sema.db, deref_trait, &[]) {
+        Some(())
+    } else {
+        None
+    }
+}
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+    use super::*;
+    #[test]
+    fn test_generate_record_deref() {
+        check_assist(
+            generate_deref,
+            r#"struct A { }
+struct B { $0a: A }"#,
+            r#"struct A { }
+struct B { a: A }
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.a
+    }
+}"#,
+        );
+    }
+    #[test]
+    fn test_generate_field_deref_idx_0() {
+        check_assist(
+            generate_deref,
+            r#"struct A { }
+struct B($0A);"#,
+            r#"struct A { }
+struct B(A);
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}"#,
+        );
+    }
+    #[test]
+    fn test_generate_field_deref_idx_1() {
+        check_assist(
+            generate_deref,
+            r#"struct A { }
+struct B(u8, $0A);"#,
+            r#"struct A { }
+struct B(u8, A);
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.1
+    }
+}"#,
+        );
+    }
+    fn check_not_applicable(ra_fixture: &str) {
+        let fixture = format!(
+            "//- /main.rs crate:main deps:core,std\n{}\n{}",
+            ra_fixture,
+            FamousDefs::FIXTURE
+        );
+        check_assist_not_applicable(generate_deref, &fixture)
+    }
+    #[test]
+    fn test_generate_record_deref_not_applicable_if_already_impl() {
+        cov_mark::check!(test_add_record_deref_impl_already_exists);
+        check_not_applicable(
+            r#"struct A { }
+struct B { $0a: A }
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.a
+    }
+}"#,
+        )
+    }
+    #[test]
+    fn test_generate_field_deref_not_applicable_if_already_impl() {
+        cov_mark::check!(test_add_field_deref_impl_already_exists);
+        check_not_applicable(
+            r#"struct A { }
+struct B($0A)
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}"#,
+        )
+    }
+}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 3694f468f..8996c1b61 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -134,6 +134,7 @@ mod handlers {
    mod generate_default_from_enum_variant;
    mod generate_default_from_new;
    mod generate_is_empty_from_len;
+    mod generate_deref;
    mod generate_derive;
    mod generate_enum_is_method;
    mod generate_enum_projection_method;
@@ -201,6 +202,7 @@ mod handlers {
            generate_default_from_enum_variant::generate_default_from_enum_variant,
            generate_default_from_new::generate_default_from_new,
            generate_is_empty_from_len::generate_is_empty_from_len,
+            generate_deref::generate_deref,
            generate_derive::generate_derive,
            generate_enum_is_method::generate_enum_is_method,
            generate_enum_projection_method::generate_enum_as_method,
diff --git a/crates/ide_assists/src/tests.rs b/crates/ide_assists/src/tests.rs
index a7a923beb..49533e7d2 100644
--- a/crates/ide_assists/src/tests.rs
+++ b/crates/ide_assists/src/tests.rs
@@ -84,7 +84,8 @@ fn check_doc_test(assist_id: &str, before: &str, after: &str) {
        });
    let actual = {
-        let source_change = assist.source_change.unwrap();
+        let source_change =
+            assist.source_change.expect("Assist did not contain any source changes");
        let mut actual = before;
        if let Some(source_file_edit) = source_change.get_source_edit(file_id) {
            source_file_edit.apply(&mut actual);
@@ -121,7 +122,8 @@ fn check(handler: Handler, before: &str, expected: ExpectedResult, assist_label:
    match (assist, expected) {
        (Some(assist), ExpectedResult::After(after)) => {
-            let source_change = assist.source_change.unwrap();
+            let source_change =
+                assist.source_change.expect("Assist did not contain any source changes");
            assert!(!source_change.source_file_edits.is_empty());
            let skip_header = source_change.source_file_edits.len() == 1
                && source_change.file_system_edits.len() == 0;
@@ -191,6 +193,7 @@ fn assist_order_field_struct() {
    let mut assists = assists.iter();
    assert_eq!(assists.next().expect("expected assist").label, "Change visibility to pub(crate)");
+    assert_eq!(assists.next().expect("expected assist").label, "Generate `Deref` impl using `bar`");
    assert_eq!(assists.next().expect("expected assist").label, "Generate a mut getter method");
    assert_eq!(assists.next().expect("expected assist").label, "Generate a getter method");
    assert_eq!(assists.next().expect("expected assist").label, "Generate a setter method");
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index 27a22ca10..41559b43a 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -552,6 +552,33 @@ impl Default for Example {
 }
 #[test]
+fn doctest_generate_deref() {
+    check_doc_test(
+        "generate_deref",
+        r#####"
+struct A;
+struct B {
+   $0a: A
+}
+"#####,
+        r#####"
+struct A;
+struct B {
+   a: A
+}
+impl std::ops::Deref for B {
+    type Target = A;
+    fn deref(&self) -> &Self::Target {
+        &self.a
+    }
+}
+"#####,
+    )
+}
+#[test]
 fn doctest_generate_derive() {
    check_doc_test(
        "generate_derive",
diff --git a/crates/ide_completion/src/completions/flyimport.rs b/crates/ide_completion/src/completions/flyimport.rs
index 5e61ecb4d..8e211ae1e 100644
--- a/crates/ide_completion/src/completions/flyimport.rs
+++ b/crates/ide_completion/src/completions/flyimport.rs
@@ -1127,4 +1127,27 @@ impl Bar for Foo {
            expect![[r#""#]],
        );
    }
+    #[test]
+    fn no_inherent_candidates_proposed() {
+        check(
+            r#"
+mod baz {
+    pub trait DefDatabase {
+        fn method1(&self);
+    }
+    pub trait HirDatabase: DefDatabase {
+        fn method2(&self);
+    }
+}
+mod bar {
+    fn test(db: &dyn crate::baz::HirDatabase) {
+        db.metho$0
+    }
+}
+            "#,
+            expect![[r#""#]],
+        );
+    }
 }
diff --git a/crates/ide_db/src/call_info.rs b/crates/ide_db/src/call_info.rs
index e583a52f4..bad277a95 100644
--- a/crates/ide_db/src/call_info.rs
+++ b/crates/ide_db/src/call_info.rs
@@ -4,8 +4,9 @@ use either::Either;
 use hir::{HasAttrs, HirDisplay, Semantics, Type};
 use stdx::format_to;
 use syntax::{
+    algo,
    ast::{self, ArgListOwner, NameOwner},
-    match_ast, AstNode, SyntaxNode, SyntaxToken, TextRange, TextSize,
+    match_ast, AstNode, Direction, SyntaxNode, SyntaxToken, TextRange, TextSize,
 };
 use crate::RootDatabase;
@@ -43,7 +44,12 @@ pub fn call_info(db: &RootDatabase, position: FilePosition) -> Option<CallInfo>
    let sema = Semantics::new(db);
    let file = sema.parse(position.file_id);
    let file = file.syntax();
-    let token = file.token_at_offset(position.offset).next()?;
+    let token = file
+        .token_at_offset(position.offset)
+        .left_biased()
+        // if the cursor is sandwiched between two space tokens and the call is unclosed
+        // this prevents us from leaving the CallExpression
+        .and_then(|tok| algo::skip_trivia_token(tok, Direction::Prev))?;
    let token = sema.descend_into_macros(token);
    let (callable, active_parameter) = call_info_impl(&sema, token)?;
diff --git a/crates/ide_db/src/call_info/tests.rs b/crates/ide_db/src/call_info/tests.rs
index 281a081a3..be1cc12de 100644
--- a/crates/ide_db/src/call_info/tests.rs
+++ b/crates/ide_db/src/call_info/tests.rs
@@ -522,3 +522,30 @@ fn main(f: fn(i32, f64) -> char) {
            "#]],
    )
 }
+#[test]
+fn call_info_for_unclosed_call() {
+    check(
+        r#"
+fn foo(foo: u32, bar: u32) {}
+fn main() {
+    foo($0
+}"#,
+        expect![[r#"
+            fn foo(foo: u32, bar: u32)
+            (<foo: u32>, bar: u32)
+        "#]],
+    );
+    // check with surrounding space
+    check(
+        r#"
+fn foo(foo: u32, bar: u32) {}
+fn main() {
+    foo( $0
+}"#,
+        expect![[r#"
+            fn foo(foo: u32, bar: u32)
+            (<foo: u32>, bar: u32)
+        "#]],
+    )
+}
diff --git a/crates/ide_db/src/helpers.rs b/crates/ide_db/src/helpers.rs
index 66798ea3a..83a665b37 100644
--- a/crates/ide_db/src/helpers.rs
+++ b/crates/ide_db/src/helpers.rs
@@ -113,6 +113,10 @@ impl FamousDefs<'_, '_> {
        self.find_module("core:iter")
    }
+    pub fn core_ops_Deref(&self) -> Option<Trait> {
+        self.find_trait("core:ops:Deref")
+    }
    fn find_trait(&self, path: &str) -> Option<Trait> {
        match self.find_def(path)? {
            hir::ScopeDef::ModuleDef(hir::ModuleDef::Trait(it)) => Some(it),
diff --git a/crates/ide_db/src/helpers/famous_defs_fixture.rs b/crates/ide_db/src/helpers/famous_defs_fixture.rs
index 4d79e064e..29ae12dcf 100644
--- a/crates/ide_db/src/helpers/famous_defs_fixture.rs
+++ b/crates/ide_db/src/helpers/famous_defs_fixture.rs
@@ -112,6 +112,12 @@ pub mod ops {
        type Output;
        extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
    }
+    #[lang = "deref"]
+    pub trait Deref {
+        type Target: ?Sized;
+        fn deref(&self) -> &Self::Target;
+    }
 }
 pub mod option {
@@ -141,3 +147,5 @@ mod return_keyword {}
 /// Docs for prim_str
 mod prim_str {}
+pub use core::ops;
+\ No newline at end of file
diff --git a/crates/ide_db/src/helpers/import_assets.rs b/crates/ide_db/src/helpers/import_assets.rs
index 8ce648367..91d6a4665 100644
--- a/crates/ide_db/src/helpers/import_assets.rs
+++ b/crates/ide_db/src/helpers/import_assets.rs
@@ -436,6 +436,8 @@ fn trait_applicable_items(
    })
    .collect();
+    let related_dyn_traits =
+        trait_candidate.receiver_ty.applicable_inherent_traits(db).collect::<FxHashSet<_>>();
    let mut located_imports = FxHashSet::default();
    if trait_assoc_item {
@@ -451,12 +453,16 @@ fn trait_applicable_items(
                            return None;
                        }
                    }
+                    let located_trait = assoc.containing_trait(db)?;
+                    if related_dyn_traits.contains(&located_trait) {
+                        return None;
+                    }
-                    let item = ItemInNs::from(ModuleDef::from(assoc.containing_trait(db)?));
+                    let trait_item = ItemInNs::from(ModuleDef::from(located_trait));
                    let original_item = assoc_to_item(assoc);
                    located_imports.insert(LocatedImport::new(
-                        mod_path(item)?,
+                        mod_path(trait_item)?,
-                        item,
+                        trait_item,
                        original_item,
                        mod_path(original_item),
                    ));
@@ -473,11 +479,15 @@ fn trait_applicable_items(
            |_, function| {
                let assoc = function.as_assoc_item(db)?;
                if required_assoc_items.contains(&assoc) {
-                    let item = ItemInNs::from(ModuleDef::from(assoc.containing_trait(db)?));
+                    let located_trait = assoc.containing_trait(db)?;
+                    if related_dyn_traits.contains(&located_trait) {
+                        return None;
+                    }
+                    let trait_item = ItemInNs::from(ModuleDef::from(located_trait));
                    let original_item = assoc_to_item(assoc);
                    located_imports.insert(LocatedImport::new(
-                        mod_path(item)?,
+                        mod_path(trait_item)?,
-                        item,
+                        trait_item,
                        original_item,
                        mod_path(original_item),
                    ));
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index 9ba98f7fb..a7c8c13c6 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -213,7 +213,7 @@ fn doc_comment_text(comment: &ast::Comment) -> SmolStr {
    // Quote the string
    // Note that `tt::Literal` expect an escaped string
-    let text = format!("{:?}", text.escape_debug().to_string());
+    let text = format!("\"{}\"", text.escape_debug());
    text.into()
 }
diff --git a/crates/mbe/src/tests/expand.rs b/crates/mbe/src/tests/expand.rs
index e02d038b6..3a1d840ea 100644
--- a/crates/mbe/src/tests/expand.rs
+++ b/crates/mbe/src/tests/expand.rs
@@ -936,7 +936,25 @@ fn test_meta_doc_comments() {
                MultiLines Doc
            */
        }"#,
-        "# [doc = \" Single Line Doc 1\"] # [doc = \"\\\\n                MultiLines Doc\\\\n            \"] fn bar () {}",
+        "# [doc = \" Single Line Doc 1\"] # [doc = \"\\n                MultiLines Doc\\n            \"] fn bar () {}",
+    );
+}
+#[test]
+fn test_meta_extended_key_value_attributes() {
+    parse_macro(
+        r#"
+macro_rules! foo {
+    (#[$i:meta]) => (
+        #[$ i]
+        fn bar() {}
+    )
+}
+"#,
+    )
+    .assert_expand_items(
+        r#"foo! { #[doc = concat!("The `", "bla", "` lang item.")] }"#,
+        r#"# [doc = concat ! ("The `" , "bla" , "` lang item.")] fn bar () {}"#,
    );
 }
@@ -959,7 +977,27 @@ fn test_meta_doc_comments_non_latin() {
                莊生曉夢迷蝴蝶，望帝春心託杜鵑。
            */
        }"#,
-        "# [doc = \" 錦瑟無端五十弦，一弦一柱思華年。\"] # [doc = \"\\\\n                莊生曉夢迷蝴蝶，望帝春心託杜鵑。\\\\n            \"] fn bar () {}",
+        "# [doc = \" 錦瑟無端五十弦，一弦一柱思華年。\"] # [doc = \"\\n                莊生曉夢迷蝴蝶，望帝春心託杜鵑。\\n            \"] fn bar () {}",
+    );
+}
+#[test]
+fn test_meta_doc_comments_escaped_characters() {
+    parse_macro(
+        r#"
+        macro_rules! foo {
+            ($(#[$ i:meta])+) => (
+                $(#[$ i])+
+                fn bar() {}
+            )
+        }
+"#,
+    )
+    .assert_expand_items(
+        r#"foo! {
+            /// \ " '
+        }"#,
+        r#"# [doc = " \\ \" \'"] fn bar () {}"#,
    );
 }
diff --git a/crates/parser/src/grammar.rs b/crates/parser/src/grammar.rs
index cebb8f400..9bdf0b5fa 100644
--- a/crates/parser/src/grammar.rs
+++ b/crates/parser/src/grammar.rs
@@ -76,42 +76,7 @@ pub(crate) mod fragments {
    // Parse a meta item , which excluded [], e.g : #[ MetaItem ]
    pub(crate) fn meta_item(p: &mut Parser) {
-        fn is_delimiter(p: &mut Parser) -> bool {
+        attributes::meta(p);
-            matches!(p.current(), T!['{'] | T!['('] | T!['['])
-        }
-        if is_delimiter(p) {
-            items::token_tree(p);
-            return;
-        }
-        let m = p.start();
-        while !p.at(EOF) {
-            if is_delimiter(p) {
-                items::token_tree(p);
-                break;
-            } else {
-                // https://doc.rust-lang.org/reference/attributes.html
-                // https://doc.rust-lang.org/reference/paths.html#simple-paths
-                // The start of an meta must be a simple path
-                match p.current() {
-                    IDENT | T![super] | T![self] | T![crate] => p.bump_any(),
-                    T![=] => {
-                        p.bump_any();
-                        match p.current() {
-                            c if c.is_literal() => p.bump_any(),
-                            T![true] | T![false] => p.bump_any(),
-                            _ => {}
-                        }
-                        break;
-                    }
-                    _ if p.at(T![::]) => p.bump(T![::]),
-                    _ => break,
-                }
-            }
-        }
-        m.complete(p, TOKEN_TREE);
    }
    pub(crate) fn item(p: &mut Parser) {
diff --git a/crates/parser/src/grammar/attributes.rs b/crates/parser/src/grammar/attributes.rs
index 96791ffc2..124a10eb2 100644
--- a/crates/parser/src/grammar/attributes.rs
+++ b/crates/parser/src/grammar/attributes.rs
@@ -14,6 +14,21 @@ pub(super) fn outer_attrs(p: &mut Parser) {
    }
 }
+pub(super) fn meta(p: &mut Parser) {
+    paths::use_path(p);
+    match p.current() {
+        T![=] => {
+            p.bump(T![=]);
+            if expressions::expr(p).0.is_none() {
+                p.error("expected expression");
+            }
+        }
+        T!['('] | T!['['] | T!['{'] => items::token_tree(p),
+        _ => {}
+    }
+}
 fn attr(p: &mut Parser, inner: bool) {
    let attr = p.start();
    assert!(p.at(T![#]));
@@ -25,18 +40,7 @@ fn attr(p: &mut Parser, inner: bool) {
    }
    if p.eat(T!['[']) {
-        paths::use_path(p);
+        meta(p);
-        match p.current() {
-            T![=] => {
-                p.bump(T![=]);
-                if expressions::expr(p).0.is_none() {
-                    p.error("expected expression");
-                }
-            }
-            T!['('] | T!['['] | T!['{'] => items::token_tree(p),
-            _ => {}
-        }
        if !p.eat(T![']']) {
            p.error("expected `]`");
diff --git a/crates/rust-analyzer/src/markdown.rs b/crates/rust-analyzer/src/markdown.rs
index 865eaae9b..a51ff89e4 100644
--- a/crates/rust-analyzer/src/markdown.rs
+++ b/crates/rust-analyzer/src/markdown.rs
@@ -27,9 +27,8 @@ pub(crate) fn format_docs(src: &str) -> String {
            in_code_block ^= true;
            if in_code_block {
-                is_rust = header
+                is_rust =
-                    .split(',')
+                    header.split(',').all(|sub| is_rust_specific_code_block_attribute(sub.trim()));
-                    .all(|sub| RUSTDOC_CODE_BLOCK_ATTRIBUTES_RUST_SPECIFIC.contains(&sub.trim()));
                if is_rust {
                    line = "```rust";
@@ -42,6 +41,13 @@ pub(crate) fn format_docs(src: &str) -> String {
    processed_lines.join("\n")
 }
+fn is_rust_specific_code_block_attribute(attr: &str) -> bool {
+    if RUSTDOC_CODE_BLOCK_ATTRIBUTES_RUST_SPECIFIC.contains(&attr) {
+        return true;
+    }
+    attr.starts_with('E') && attr.len() == 5 && attr[1..].parse::<u32>().is_ok()
+}
 fn code_line_ignored_by_rustdoc(line: &str) -> bool {
    let trimmed = line.trim();
    trimmed == "#" || trimmed.starts_with("# ") || trimmed.starts_with("#\t")
@@ -82,6 +88,12 @@ mod tests {
    }
    #[test]
+    fn test_format_docs_handles_error_codes() {
+        let comment = "```compile_fail,E0641\nlet b = 0 as *const _;\n```";
+        assert_eq!(format_docs(comment), "```rust\nlet b = 0 as *const _;\n```");
+    }
+    #[test]
    fn test_format_docs_skips_comments_in_rust_block() {
        let comment =
            "```rust\n # skip1\n# skip2\n#stay1\nstay2\n#\n #\n   #    \n #\tskip3\n\t#\t\n```";
diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index f09cdf28a..a8c1a8075 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 [dependencies]
 cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
-rowan = "0.13.0-pre.3"
+rowan = "=0.13.0-pre.3"
 rustc_lexer = { version = "714.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
 arrayvec = "0.7"
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index c6a7b99b7..94d4f2cf0 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -29,9 +29,13 @@ pub fn ty(text: &str) -> ast::Type {
 pub fn ty_unit() -> ast::Type {
    ty("()")
 }
-// FIXME: handle types of length == 1
 pub fn ty_tuple(types: impl IntoIterator<Item = ast::Type>) -> ast::Type {
-    let contents = types.into_iter().join(", ");
+    let mut count: usize = 0;
+    let mut contents = types.into_iter().inspect(|_| count += 1).join(", ");
+    if count == 1 {
+        contents.push(',');
+    }
    ty(&format!("({})", contents))
 }
 // FIXME: handle path to type
@@ -292,11 +296,13 @@ pub fn wildcard_pat() -> ast::WildcardPat {
 /// Creates a tuple of patterns from an iterator of patterns.
 ///
-/// Invariant: `pats` must be length > 1
+/// Invariant: `pats` must be length > 0
-///
-/// FIXME handle `pats` length == 1
 pub fn tuple_pat(pats: impl IntoIterator<Item = ast::Pat>) -> ast::TuplePat {
-    let pats_str = pats.into_iter().map(|p| p.to_string()).join(", ");
+    let mut count: usize = 0;
+    let mut pats_str = pats.into_iter().inspect(|_| count += 1).join(", ");
+    if count == 1 {
+        pats_str.push(',');
+    }
    return from_text(&format!("({})", pats_str));
    fn from_text(text: &str) -> ast::TuplePat {