74 files changed, 2711 insertions, 1655 deletions

diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 817a01db1..eba46a056 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -1580,11 +1580,24 @@ impl Impl {
             ty.equals_ctor(rref.as_ref().map_or(&self_ty.ty, |it| &it.ty))
         };
 
+        let fp = TyFingerprint::for_inherent_impl(&ty);
+        let fp = if let Some(fp) = fp {
+            fp
+        } else {
+            return Vec::new();
+        };
+
         let mut all = Vec::new();
         def_crates.iter().for_each(|&id| {
-            all.extend(db.inherent_impls_in_crate(id).all_impls().map(Self::from).filter(filter))
+            all.extend(
+                db.inherent_impls_in_crate(id)
+                    .for_self_ty(&ty)
+                    .into_iter()
+                    .cloned()
+                    .map(Self::from)
+                    .filter(filter),
+            )
         });
-        let fp = TyFingerprint::for_impl(&ty);
         for id in def_crates
             .iter()
             .flat_map(|&id| Crate { id }.transitive_reverse_dependencies(db))
@@ -1592,13 +1605,12 @@ impl Impl {
             .chain(def_crates.iter().copied())
             .unique()
         {
-            match fp {
-                Some(fp) => all.extend(
-                    db.trait_impls_in_crate(id).for_self_ty(fp).map(Self::from).filter(filter),
-                ),
-                None => all
-                    .extend(db.trait_impls_in_crate(id).all_impls().map(Self::from).filter(filter)),
-            }
+            all.extend(
+                db.trait_impls_in_crate(id)
+                    .for_self_ty_without_blanket_impls(fp)
+                    .map(Self::from)
+                    .filter(filter),
+            );
         }
         all
     }
@@ -1825,7 +1837,7 @@ impl Type {
             Solution::Unique(s) => s
                 .value
                 .subst
-                .interned()
+                .as_slice(&Interner)
                 .first()
                 .map(|ty| self.derived(ty.assert_ty_ref(&Interner).clone())),
             Solution::Ambig(_) => None,
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index d9df7564d..786fad6e1 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -9,7 +9,7 @@ use std::{
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
 use either::Either;
-use hir_expand::{hygiene::Hygiene, name::AsName, AstId, InFile};
+use hir_expand::{hygiene::Hygiene, name::AsName, AstId, AttrId, InFile};
 use itertools::Itertools;
 use la_arena::ArenaMap;
 use mbe::ast_to_token_tree;
@@ -98,13 +98,16 @@ impl RawAttrs {
     pub(crate) fn new(owner: &dyn ast::AttrsOwner, hygiene: &Hygiene) -> Self {
         let entries = collect_attrs(owner)
             .enumerate()
-            .flat_map(|(i, attr)| match attr {
-                Either::Left(attr) => Attr::from_src(attr, hygiene, i as u32),
-                Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
-                    index: i as u32,
-                    input: Some(AttrInput::Literal(SmolStr::new(doc))),
-                    path: Interned::new(ModPath::from(hir_expand::name!(doc))),
-                }),
+            .flat_map(|(i, attr)| {
+                let index = AttrId(i as u32);
+                match attr {
+                    Either::Left(attr) => Attr::from_src(attr, hygiene, index),
+                    Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
+                        id: index,
+                        input: Some(AttrInput::Literal(SmolStr::new(doc))),
+                        path: Interned::new(ModPath::from(hir_expand::name!(doc))),
+                    }),
+                }
             })
             .collect::<Arc<_>>();
 
@@ -161,7 +164,7 @@ impl RawAttrs {
                 let cfg = parts.next().unwrap();
                 let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
                 let cfg = CfgExpr::parse(&cfg);
-                let index = attr.index;
+                let index = attr.id;
                 let attrs = parts.filter(|a| !a.is_empty()).filter_map(|attr| {
                     let tree = Subtree { delimiter: None, token_trees: attr.to_vec() };
                     let attr = ast::Attr::parse(&format!("#[{}]", tree)).ok()?;
@@ -468,7 +471,7 @@ impl AttrsWithOwner {
     ) -> Option<(Documentation, DocsRangeMap)> {
         // FIXME: code duplication in `docs` above
         let docs = self.by_key("doc").attrs().flat_map(|attr| match attr.input.as_ref()? {
-            AttrInput::Literal(s) => Some((s, attr.index)),
+            AttrInput::Literal(s) => Some((s, attr.id)),
             AttrInput::TokenTree(_) => None,
         });
         let indent = docs
@@ -560,8 +563,8 @@ impl AttrSourceMap {
     /// the attribute represented by `Attr`.
     pub fn source_of(&self, attr: &Attr) -> InFile<&Either<ast::Attr, ast::Comment>> {
         self.attrs
-            .get(attr.index as usize)
-            .unwrap_or_else(|| panic!("cannot find `Attr` at index {}", attr.index))
+            .get(attr.id.0 as usize)
+            .unwrap_or_else(|| panic!("cannot find `Attr` at index {:?}", attr.id))
             .as_ref()
     }
 }
@@ -572,7 +575,7 @@ pub struct DocsRangeMap {
     // (docstring-line-range, attr_index, attr-string-range)
     // a mapping from the text range of a line of the [`Documentation`] to the attribute index and
     // the original (untrimmed) syntax doc line
-    mapping: Vec<(TextRange, u32, TextRange)>,
+    mapping: Vec<(TextRange, AttrId, TextRange)>,
 }
 
 impl DocsRangeMap {
@@ -585,7 +588,7 @@ impl DocsRangeMap {
 
         let relative_range = range - line_docs_range.start();
 
-        let &InFile { file_id, value: ref source } = &self.source[idx as usize];
+        let &InFile { file_id, value: ref source } = &self.source[idx.0 as usize];
         match source {
             Either::Left(_) => None, // FIXME, figure out a nice way to handle doc attributes here
             // as well as for whats done in syntax highlight doc injection
@@ -606,7 +609,7 @@ impl DocsRangeMap {
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Attr {
-    index: u32,
+    pub(crate) id: AttrId,
     pub(crate) path: Interned<ModPath>,
     pub(crate) input: Option<AttrInput>,
 }
@@ -620,7 +623,7 @@ pub enum AttrInput {
 }
 
 impl Attr {
-    fn from_src(ast: ast::Attr, hygiene: &Hygiene, index: u32) -> Option<Attr> {
+    fn from_src(ast: ast::Attr, hygiene: &Hygiene, id: AttrId) -> Option<Attr> {
         let path = Interned::new(ModPath::from_src(ast.path()?, hygiene)?);
         let input = if let Some(ast::Expr::Literal(lit)) = ast.expr() {
             let value = match lit.kind() {
@@ -633,7 +636,7 @@ impl Attr {
         } else {
             None
         };
-        Some(Attr { index, path, input })
+        Some(Attr { id, path, input })
     }
 
     /// Parses this attribute as a `#[derive]`, returns an iterator that yields all contained paths
@@ -748,9 +751,7 @@ fn collect_attrs(
         .chain(inner_docs.into_iter().flatten())
         .map(|docs_text| (docs_text.syntax().text_range().start(), Either::Right(docs_text)));
     // sort here by syntax node offset because the source can have doc attributes and doc strings be interleaved
-    let attrs: Vec<_> = docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).collect();
-
-    attrs.into_iter().map(|(_, attr)| attr)
+    docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).map(|(_, attr)| attr)
 }
 
 pub(crate) fn variants_attrs_source_map(
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index bfb75a8a5..ed07d6928 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -531,8 +531,9 @@ impl ExprCollector<'_> {
                 }
             }
             ast::Expr::MacroCall(e) => {
+                let macro_ptr = AstPtr::new(&e);
                 let mut ids = vec![];
-                self.collect_macro_call(e, syntax_ptr.clone(), true, |this, expansion| {
+                self.collect_macro_call(e, macro_ptr, true, |this, expansion| {
                     ids.push(match expansion {
                         Some(it) => this.collect_expr(it),
                         None => this.alloc_expr(Expr::Missing, syntax_ptr.clone()),
@@ -555,7 +556,7 @@ impl ExprCollector<'_> {
     fn collect_macro_call<F: FnMut(&mut Self, Option<T>), T: ast::AstNode>(
         &mut self,
         e: ast::MacroCall,
-        syntax_ptr: AstPtr<ast::Expr>,
+        syntax_ptr: AstPtr<ast::MacroCall>,
         is_error_recoverable: bool,
         mut collector: F,
     ) {
@@ -643,10 +644,14 @@ impl ExprCollector<'_> {
 
                 // Note that macro could be expended to multiple statements
                 if let Some(ast::Expr::MacroCall(m)) = stmt.expr() {
+                    let macro_ptr = AstPtr::new(&m);
                     let syntax_ptr = AstPtr::new(&stmt.expr().unwrap());
 
-                    self.collect_macro_call(m, syntax_ptr.clone(), false, |this, expansion| {
-                        match expansion {
+                    self.collect_macro_call(
+                        m,
+                        macro_ptr,
+                        false,
+                        |this, expansion| match expansion {
                             Some(expansion) => {
                                 let statements: ast::MacroStmts = expansion;
 
@@ -660,8 +665,8 @@ impl ExprCollector<'_> {
                                 let expr = this.alloc_expr(Expr::Missing, syntax_ptr.clone());
                                 this.statements_in_scope.push(Statement::Expr(expr));
                             }
-                        }
-                    });
+                        },
+                    );
                 } else {
                     let expr = self.collect_expr_opt(stmt.expr());
                     self.statements_in_scope.push(Statement::Expr(expr));
@@ -848,8 +853,23 @@ impl ExprCollector<'_> {
                     Pat::Missing
                 }
             }
+            ast::Pat::MacroPat(mac) => match mac.macro_call() {
+                Some(call) => {
+                    let macro_ptr = AstPtr::new(&call);
+                    let mut pat = None;
+                    self.collect_macro_call(call, macro_ptr, true, |this, expanded_pat| {
+                        pat = Some(this.collect_pat_opt(expanded_pat));
+                    });
+
+                    match pat {
+                        Some(pat) => return pat,
+                        None => Pat::Missing,
+                    }
+                }
+                None => Pat::Missing,
+            },
             // FIXME: implement
-            ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
+            ast::Pat::RangePat(_) => Pat::Missing,
         };
         let ptr = AstPtr::new(&pat);
         self.alloc_pat(pattern, Either::Left(ptr))
diff --git a/crates/hir_def/src/child_by_source.rs b/crates/hir_def/src/child_by_source.rs
index f40a7f80d..f2e809ca9 100644
--- a/crates/hir_def/src/child_by_source.rs
+++ b/crates/hir_def/src/child_by_source.rs
@@ -80,6 +80,10 @@ impl ChildBySource for ModuleId {
 impl ChildBySource for ItemScope {
     fn child_by_source_to(&self, db: &dyn DefDatabase, res: &mut DynMap) {
         self.declarations().for_each(|item| add_module_def(db, res, item));
+        self.unnamed_consts().for_each(|konst| {
+            let src = konst.lookup(db).source(db);
+            res[keys::CONST].insert(src, konst);
+        });
         self.impls().for_each(|imp| add_impl(db, res, imp));
 
         fn add_module_def(db: &dyn DefDatabase, map: &mut DynMap, item: ModuleDefId) {
diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index 240662486..94e08f835 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -99,6 +99,11 @@ impl ItemTree {
                     // items.
                     ctx.lower_macro_stmts(stmts)
                 },
+                ast::Pat(_pat) => {
+                    // FIXME: This occurs because macros in pattern position are treated as inner
+                    // items and expanded during block DefMap computation
+                    return Default::default();
+                },
                 ast::Expr(e) => {
                     // Macros can expand to expressions. We return an empty item tree in this case, but
                     // still need to collect inner items.
diff --git a/crates/hir_def/src/item_tree/lower.rs b/crates/hir_def/src/item_tree/lower.rs
index c5629af24..45b099cf3 100644
--- a/crates/hir_def/src/item_tree/lower.rs
+++ b/crates/hir_def/src/item_tree/lower.rs
@@ -189,7 +189,7 @@ impl Ctx {
                                 block_stack.push(self.source_ast_id_map.ast_id(&block));
                             },
                             ast::Item(item) => {
-                                // FIXME: This triggers for macro calls in expression position
+                                // FIXME: This triggers for macro calls in expression/pattern/type position
                                 let mod_items = self.lower_mod_item(&item, true);
                                 let current_block = block_stack.last();
                                 if let (Some(mod_items), Some(block)) = (mod_items, current_block) {
diff --git a/crates/hir_def/src/lib.rs b/crates/hir_def/src/lib.rs
index e2af0e514..d69116d51 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -62,7 +62,7 @@ use hir_expand::{
     ast_id_map::FileAstId,
     eager::{expand_eager_macro, ErrorEmitted, ErrorSink},
     hygiene::Hygiene,
-    AstId, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    AstId, AttrId, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
 };
 use la_arena::Idx;
 use nameres::DefMap;
@@ -690,13 +690,16 @@ fn macro_call_as_call_id(
         )
         .map(MacroCallId::from)
     } else {
-        Ok(def.as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike(call.ast_id)).into())
+        Ok(def
+            .as_lazy_macro(db.upcast(), krate, MacroCallKind::FnLike { ast_id: call.ast_id })
+            .into())
     };
     Ok(res)
 }
 
 fn derive_macro_as_call_id(
     item_attr: &AstIdWithPath<ast::Item>,
+    derive_attr: AttrId,
     db: &dyn db::DefDatabase,
     krate: CrateId,
     resolver: impl Fn(path::ModPath) -> Option<MacroDefId>,
@@ -707,7 +710,11 @@ fn derive_macro_as_call_id(
         .as_lazy_macro(
             db.upcast(),
             krate,
-            MacroCallKind::Derive(item_attr.ast_id, last_segment.to_string()),
+            MacroCallKind::Derive {
+                ast_id: item_attr.ast_id,
+                derive_name: last_segment.to_string(),
+                derive_attr,
+            },
         )
         .into();
     Ok(res)
diff --git a/crates/hir_def/src/nameres.rs b/crates/hir_def/src/nameres.rs
index 7dd68219f..9e181751c 100644
--- a/crates/hir_def/src/nameres.rs
+++ b/crates/hir_def/src/nameres.rs
@@ -613,12 +613,12 @@ mod diagnostics {
                 DiagnosticKind::UnresolvedProcMacro { ast } => {
                     let mut precise_location = None;
                     let (file, ast, name) = match ast {
-                        MacroCallKind::FnLike(ast) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
+                        MacroCallKind::FnLike { ast_id } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
                         }
-                        MacroCallKind::Derive(ast, name) => {
-                            let node = ast.to_node(db.upcast());
+                        MacroCallKind::Derive { ast_id, derive_name, .. } => {
+                            let node = ast_id.to_node(db.upcast());
 
                             // Compute the precise location of the macro name's token in the derive
                             // list.
@@ -639,7 +639,7 @@ mod diagnostics {
                                     });
                                 for token in tokens {
                                     if token.kind() == SyntaxKind::IDENT
-                                        && token.text() == name.as_str()
+                                        && token.text() == derive_name.as_str()
                                     {
                                         precise_location = Some(token.text_range());
                                         break 'outer;
@@ -648,9 +648,9 @@ mod diagnostics {
                             }
 
                             (
-                                ast.file_id,
+                                ast_id.file_id,
                                 SyntaxNodePtr::from(AstPtr::new(&node)),
-                                Some(name.clone()),
+                                Some(derive_name.clone()),
                             )
                         }
                     };
@@ -669,13 +669,13 @@ mod diagnostics {
 
                 DiagnosticKind::MacroError { ast, message } => {
                     let (file, ast) = match ast {
-                        MacroCallKind::FnLike(ast) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                        MacroCallKind::FnLike { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
                         }
-                        MacroCallKind::Derive(ast, _) => {
-                            let node = ast.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                        MacroCallKind::Derive { ast_id, .. } => {
+                            let node = ast_id.to_node(db.upcast());
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
                         }
                     };
                     sink.push(MacroError { file, node: ast, message: message.clone() });
diff --git a/crates/hir_def/src/nameres/collector.rs b/crates/hir_def/src/nameres/collector.rs
index 6dbbe2d05..fb4ddff5e 100644
--- a/crates/hir_def/src/nameres/collector.rs
+++ b/crates/hir_def/src/nameres/collector.rs
@@ -13,7 +13,7 @@ use hir_expand::{
     builtin_macro::find_builtin_macro,
     name::{AsName, Name},
     proc_macro::ProcMacroExpander,
-    HirFileId, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
+    AttrId, HirFileId, MacroCallId, MacroCallKind, MacroDefId, MacroDefKind,
 };
 use hir_expand::{InFile, MacroCallLoc};
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -216,7 +216,7 @@ struct MacroDirective {
 #[derive(Clone, Debug, Eq, PartialEq)]
 enum MacroDirectiveKind {
     FnLike { ast_id: AstIdWithPath<ast::MacroCall> },
-    Derive { ast_id: AstIdWithPath<ast::Item> },
+    Derive { ast_id: AstIdWithPath<ast::Item>, derive_attr: AttrId },
 }
 
 struct DefData<'a> {
@@ -478,7 +478,7 @@ impl DefCollector<'_> {
             self.def_map.edition,
         );
 
-        let res = self.def_map.resolve_name_in_extern_prelude(&extern_crate.name);
+        let res = self.def_map.resolve_name_in_extern_prelude(self.db, &extern_crate.name);
 
         if let Some(ModuleDefId::ModuleId(m)) = res.take_types() {
             cov_mark::hit!(macro_rules_from_other_crates_are_visible_with_macro_use);
@@ -534,6 +534,7 @@ impl DefCollector<'_> {
         log::debug!("resolving import: {:?} ({:?})", import, self.def_map.edition);
         if import.is_extern_crate {
             let res = self.def_map.resolve_name_in_extern_prelude(
+                self.db,
                 &import
                     .path
                     .as_ident()
@@ -831,10 +832,14 @@ impl DefCollector<'_> {
                         Err(UnresolvedMacro) | Ok(Err(_)) => {}
                     }
                 }
-                MacroDirectiveKind::Derive { ast_id } => {
-                    match derive_macro_as_call_id(ast_id, self.db, self.def_map.krate, |path| {
-                        self.resolve_derive_macro(directive.module_id, &path)
-                    }) {
+                MacroDirectiveKind::Derive { ast_id, derive_attr } => {
+                    match derive_macro_as_call_id(
+                        ast_id,
+                        *derive_attr,
+                        self.db,
+                        self.def_map.krate,
+                        |path| self.resolve_derive_macro(directive.module_id, &path),
+                    ) {
                         Ok(call_id) => {
                             resolved.push((directive.module_id, call_id, directive.depth));
                             res = ReachedFixedPoint::No;
@@ -1368,7 +1373,7 @@ impl ModCollector<'_, '_> {
                         self.def_collector.unexpanded_macros.push(MacroDirective {
                             module_id: self.module_id,
                             depth: self.macro_depth + 1,
-                            kind: MacroDirectiveKind::Derive { ast_id },
+                            kind: MacroDirectiveKind::Derive { ast_id, derive_attr: derive.id },
                         });
                     }
                 }
@@ -1520,7 +1525,7 @@ impl ModCollector<'_, '_> {
                 // Built-in macro failed eager expansion.
                 self.def_collector.def_map.diagnostics.push(DefDiagnostic::macro_error(
                     self.module_id,
-                    MacroCallKind::FnLike(ast_id.ast_id),
+                    MacroCallKind::FnLike { ast_id: ast_id.ast_id },
                     error.unwrap().to_string(),
                 ));
                 return;
diff --git a/crates/hir_def/src/nameres/path_resolution.rs b/crates/hir_def/src/nameres/path_resolution.rs
index 60471937c..ccc9f22eb 100644
--- a/crates/hir_def/src/nameres/path_resolution.rs
+++ b/crates/hir_def/src/nameres/path_resolution.rs
@@ -60,12 +60,26 @@ impl ResolvePathResult {
 }
 
 impl DefMap {
-    pub(super) fn resolve_name_in_extern_prelude(&self, name: &Name) -> PerNs {
+    pub(super) fn resolve_name_in_extern_prelude(
+        &self,
+        db: &dyn DefDatabase,
+        name: &Name,
+    ) -> PerNs {
         if name == &name!(self) {
             cov_mark::hit!(extern_crate_self_as);
             return PerNs::types(self.module_id(self.root).into(), Visibility::Public);
         }
-        self.extern_prelude
+
+        let arc;
+        let root = match self.block {
+            Some(_) => {
+                arc = self.crate_root(db).def_map(db);
+                &*arc
+            }
+            None => self,
+        };
+
+        root.extern_prelude
             .get(name)
             .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public))
     }
@@ -191,7 +205,7 @@ impl DefMap {
                     None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
                 };
                 log::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
-                self.resolve_name_in_crate_root_or_extern_prelude(&segment)
+                self.resolve_name_in_crate_root_or_extern_prelude(db, &segment)
             }
             PathKind::Plain => {
                 let (_, segment) = match segments.next() {
@@ -384,24 +398,31 @@ impl DefMap {
                 }
             }
         };
-        // Give precedence to names in outer `DefMap`s over the extern prelude; only check prelude
-        // from the crate DefMap.
-        let from_extern_prelude = match self.block {
-            Some(_) => PerNs::none(),
-            None => self
-                .extern_prelude
-                .get(name)
-                .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public)),
-        };
+        let from_extern_prelude = self
+            .extern_prelude
+            .get(name)
+            .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public));
 
         let from_prelude = self.resolve_in_prelude(db, name);
 
         from_legacy_macro.or(from_scope_or_builtin).or(from_extern_prelude).or(from_prelude)
     }
 
-    fn resolve_name_in_crate_root_or_extern_prelude(&self, name: &Name) -> PerNs {
-        let from_crate_root = self[self.root].scope.get(name);
-        let from_extern_prelude = self.resolve_name_in_extern_prelude(name);
+    fn resolve_name_in_crate_root_or_extern_prelude(
+        &self,
+        db: &dyn DefDatabase,
+        name: &Name,
+    ) -> PerNs {
+        let arc;
+        let crate_def_map = match self.block {
+            Some(_) => {
+                arc = self.crate_root(db).def_map(db);
+                &arc
+            }
+            None => self,
+        };
+        let from_crate_root = crate_def_map[crate_def_map.root].scope.get(name);
+        let from_extern_prelude = self.resolve_name_in_extern_prelude(db, name);
 
         from_crate_root.or(from_extern_prelude)
     }
diff --git a/crates/hir_expand/src/builtin_derive.rs b/crates/hir_expand/src/builtin_derive.rs
index 6ece4b289..537c03028 100644
--- a/crates/hir_expand/src/builtin_derive.rs
+++ b/crates/hir_expand/src/builtin_derive.rs
@@ -269,7 +269,7 @@ mod tests {
     use expect_test::{expect, Expect};
     use name::AsName;
 
-    use crate::{test_db::TestDB, AstId, MacroCallId, MacroCallKind, MacroCallLoc};
+    use crate::{test_db::TestDB, AstId, AttrId, MacroCallId, MacroCallKind, MacroCallLoc};
 
     use super::*;
 
@@ -308,7 +308,7 @@ $0
 
         let expander = BuiltinDeriveExpander::find_by_name(&name).unwrap();
 
-        let attr_id = AstId::new(file_id.into(), ast_id_map.ast_id(&items[0]));
+        let ast_id = AstId::new(file_id.into(), ast_id_map.ast_id(&items[0]));
 
         let loc = MacroCallLoc {
             def: MacroDefId {
@@ -317,7 +317,11 @@ $0
                 local_inner: false,
             },
             krate: CrateId(0),
-            kind: MacroCallKind::Derive(attr_id, name.to_string()),
+            kind: MacroCallKind::Derive {
+                ast_id,
+                derive_name: name.to_string(),
+                derive_attr: AttrId(0),
+            },
         };
 
         let id: MacroCallId = db.intern_macro(loc).into();
diff --git a/crates/hir_expand/src/builtin_macro.rs b/crates/hir_expand/src/builtin_macro.rs
index a7d0f5b1f..80365fc16 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -566,10 +566,9 @@ mod tests {
                 let loc = MacroCallLoc {
                     def,
                     krate,
-                    kind: MacroCallKind::FnLike(AstId::new(
-                        file_id.into(),
-                        ast_id_map.ast_id(&macro_call),
-                    )),
+                    kind: MacroCallKind::FnLike {
+                        ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call)),
+                    },
                 };
 
                 let id: MacroCallId = db.intern_macro(loc).into();
diff --git a/crates/hir_expand/src/db.rs b/crates/hir_expand/src/db.rs
index 10fe60821..ca705ee9d 100644
--- a/crates/hir_expand/src/db.rs
+++ b/crates/hir_expand/src/db.rs
@@ -439,6 +439,7 @@ fn to_fragment_kind(db: &dyn AstDatabase, id: MacroCallId) -> FragmentKind {
     match parent.kind() {
         MACRO_ITEMS | SOURCE_FILE => FragmentKind::Items,
         MACRO_STMTS => FragmentKind::Statements,
+        MACRO_PAT => FragmentKind::Pattern,
         ITEM_LIST => FragmentKind::Items,
         LET_STMT => {
             // FIXME: Handle LHS Pattern
diff --git a/crates/hir_expand/src/eager.rs b/crates/hir_expand/src/eager.rs
index 9705526fa..ef126e4ad 100644
--- a/crates/hir_expand/src/eager.rs
+++ b/crates/hir_expand/src/eager.rs
@@ -174,8 +174,9 @@ fn lazy_expand(
 ) -> ExpandResult<Option<InFile<SyntaxNode>>> {
     let ast_id = db.ast_id_map(macro_call.file_id).ast_id(&macro_call.value);
 
-    let id: MacroCallId =
-        def.as_lazy_macro(db, krate, MacroCallKind::FnLike(macro_call.with_value(ast_id))).into();
+    let id: MacroCallId = def
+        .as_lazy_macro(db, krate, MacroCallKind::FnLike { ast_id: macro_call.with_value(ast_id) })
+        .into();
 
     let err = db.macro_expand_error(id);
     let value = db.parse_or_expand(id.as_file()).map(|node| InFile::new(id.as_file(), node));
diff --git a/crates/hir_expand/src/lib.rs b/crates/hir_expand/src/lib.rs
index 3e332ee47..a0e6aec62 100644
--- a/crates/hir_expand/src/lib.rs
+++ b/crates/hir_expand/src/lib.rs
@@ -290,22 +290,27 @@ pub struct MacroCallLoc {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum MacroCallKind {
-    FnLike(AstId<ast::MacroCall>),
-    Derive(AstId<ast::Item>, String),
+    FnLike { ast_id: AstId<ast::MacroCall> },
+    Derive { ast_id: AstId<ast::Item>, derive_name: String, derive_attr: AttrId },
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct AttrId(pub u32);
+
 impl MacroCallKind {
     fn file_id(&self) -> HirFileId {
         match self {
-            MacroCallKind::FnLike(ast_id) => ast_id.file_id,
-            MacroCallKind::Derive(ast_id, _) => ast_id.file_id,
+            MacroCallKind::FnLike { ast_id, .. } => ast_id.file_id,
+            MacroCallKind::Derive { ast_id, .. } => ast_id.file_id,
         }
     }
 
     fn node(&self, db: &dyn db::AstDatabase) -> InFile<SyntaxNode> {
         match self {
-            MacroCallKind::FnLike(ast_id) => ast_id.with_value(ast_id.to_node(db).syntax().clone()),
-            MacroCallKind::Derive(ast_id, _) => {
+            MacroCallKind::FnLike { ast_id, .. } => {
+                ast_id.with_value(ast_id.to_node(db).syntax().clone())
+            }
+            MacroCallKind::Derive { ast_id, .. } => {
                 ast_id.with_value(ast_id.to_node(db).syntax().clone())
             }
         }
@@ -313,10 +318,10 @@ impl MacroCallKind {
 
     fn arg(&self, db: &dyn db::AstDatabase) -> Option<SyntaxNode> {
         match self {
-            MacroCallKind::FnLike(ast_id) => {
+            MacroCallKind::FnLike { ast_id, .. } => {
                 Some(ast_id.to_node(db).token_tree()?.syntax().clone())
             }
-            MacroCallKind::Derive(ast_id, _) => Some(ast_id.to_node(db).syntax().clone()),
+            MacroCallKind::Derive { ast_id, .. } => Some(ast_id.to_node(db).syntax().clone()),
         }
     }
 }
diff --git a/crates/hir_ty/src/autoderef.rs b/crates/hir_ty/src/autoderef.rs
index f8e9db9ae..71bc436e6 100644
--- a/crates/hir_ty/src/autoderef.rs
+++ b/crates/hir_ty/src/autoderef.rs
@@ -6,14 +6,15 @@
 use std::iter::successors;
 
 use base_db::CrateId;
-use chalk_ir::cast::Cast;
+use chalk_ir::{cast::Cast, fold::Fold, interner::HasInterner, VariableKind};
 use hir_def::lang_item::LangItemTarget;
 use hir_expand::name::name;
 use log::{info, warn};
 
 use crate::{
-    db::HirDatabase, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex,
-    InEnvironment, Interner, ProjectionTyExt, Solution, Ty, TyBuilder, TyKind,
+    db::HirDatabase, static_lifetime, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds,
+    DebruijnIndex, InEnvironment, Interner, ProjectionTyExt, Solution, Substitution, Ty, TyBuilder,
+    TyKind,
 };
 
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
@@ -103,7 +104,7 @@ fn deref_by_trait(
         binders: CanonicalVarKinds::from_iter(
             &Interner,
             ty.goal.binders.iter(&Interner).cloned().chain(Some(chalk_ir::WithKind::new(
-                chalk_ir::VariableKind::Ty(chalk_ir::TyVariableKind::General),
+                VariableKind::Ty(chalk_ir::TyVariableKind::General),
                 chalk_ir::UniverseIndex::ROOT,
             ))),
         ),
@@ -136,7 +137,9 @@ fn deref_by_trait(
                     return None;
                 }
             }
-            Some(Canonical {
+            // FIXME: we remove lifetime variables here since they can confuse
+            // the method resolution code later
+            Some(fixup_lifetime_variables(Canonical {
                 value: vars
                     .value
                     .subst
@@ -144,7 +147,7 @@ fn deref_by_trait(
                     .assert_ty_ref(&Interner)
                     .clone(),
                 binders: vars.binders.clone(),
-            })
+            }))
         }
         Solution::Ambig(_) => {
             info!("Ambiguous solution for derefing {:?}: {:?}", ty.goal, solution);
@@ -152,3 +155,32 @@ fn deref_by_trait(
         }
     }
 }
+
+fn fixup_lifetime_variables<T: Fold<Interner, Result = T> + HasInterner<Interner = Interner>>(
+    c: Canonical<T>,
+) -> Canonical<T> {
+    // Removes lifetime variables from the Canonical, replacing them by static lifetimes.
+    let mut i = 0;
+    let subst = Substitution::from_iter(
+        &Interner,
+        c.binders.iter(&Interner).map(|vk| match vk.kind {
+            VariableKind::Ty(_) => {
+                let index = i;
+                i += 1;
+                BoundVar::new(DebruijnIndex::INNERMOST, index).to_ty(&Interner).cast(&Interner)
+            }
+            VariableKind::Lifetime => static_lifetime().cast(&Interner),
+            VariableKind::Const(_) => unimplemented!(),
+        }),
+    );
+    let binders = CanonicalVarKinds::from_iter(
+        &Interner,
+        c.binders.iter(&Interner).filter(|vk| match vk.kind {
+            VariableKind::Ty(_) => true,
+            VariableKind::Lifetime => false,
+            VariableKind::Const(_) => true,
+        }),
+    );
+    let value = subst.apply(c.value, &Interner);
+    Canonical { binders, value }
+}
diff --git a/crates/hir_ty/src/chalk_cast.rs b/crates/hir_ty/src/chalk_cast.rs
deleted file mode 100644
index f27dee3fd..000000000
--- a/crates/hir_ty/src/chalk_cast.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-//! Implementations of the Chalk `Cast` trait for our types.
-
-use chalk_ir::interner::HasInterner;
-
-use crate::{CallableSig, ReturnTypeImplTraits};
-
-macro_rules! has_interner {
-    ($t:ty) => {
-        impl HasInterner for $t {
-            type Interner = crate::Interner;
-        }
-    };
-}
-
-has_interner!(CallableSig);
-has_interner!(ReturnTypeImplTraits);
diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/chalk_db.rs
index b8c390b2e..8f054d06b 100644
--- a/crates/hir_ty/src/traits/chalk.rs
+++ b/crates/hir_ty/src/chalk_db.rs
@@ -1,50 +1,47 @@
-//! Conversion code from/to Chalk.
+//! The implementation of `RustIrDatabase` for Chalk, which provides information
+//! about the code that Chalk needs.
 use std::sync::Arc;
 
 use log::debug;
 
-use chalk_ir::{fold::shift::Shift, CanonicalVarKinds};
+use chalk_ir::{cast::Cast, fold::shift::Shift, CanonicalVarKinds};
 use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
 
-use base_db::{salsa::InternKey, CrateId};
+use base_db::CrateId;
 use hir_def::{
     lang_item::{lang_attr, LangItemTarget},
-    AssocContainerId, AssocItemId, HasModule, Lookup, TypeAliasId,
+    AssocContainerId, AssocItemId, GenericDefId, HasModule, Lookup, TypeAliasId,
 };
 use hir_expand::name::name;
 
-use super::ChalkContext;
 use crate::{
     db::HirDatabase,
     display::HirDisplay,
-    from_assoc_type_id, make_only_type_binders,
+    from_assoc_type_id, from_chalk_trait_id, make_only_type_binders,
+    mapping::{from_chalk, ToChalk, TypeAliasAsValue},
     method_resolution::{TyFingerprint, ALL_FLOAT_FPS, ALL_INT_FPS},
     to_assoc_type_id, to_chalk_trait_id,
+    traits::ChalkContext,
     utils::generics,
-    AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, ProjectionTy, Substitution,
-    TraitRef, TraitRefExt, Ty, TyBuilder, TyExt, TyKind, WhereClause,
+    AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, Interner, ProjectionTy,
+    ProjectionTyExt, QuantifiedWhereClause, Substitution, TraitRef, TraitRefExt, Ty, TyBuilder,
+    TyExt, TyKind, WhereClause,
 };
-use mapping::{convert_where_clauses, generic_predicate_to_inline_bound, TypeAliasAsValue};
 
-pub use self::interner::Interner;
-pub(crate) use self::interner::*;
-
-pub(super) mod tls;
-mod interner;
-mod mapping;
-
-pub(crate) trait ToChalk {
-    type Chalk;
-    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
-    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
-}
-
-pub(crate) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
-where
-    T: ToChalk<Chalk = ChalkT>,
-{
-    T::from_chalk(db, chalk)
-}
+pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
+pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
+pub(crate) type StructDatum = chalk_solve::rust_ir::AdtDatum<Interner>;
+pub(crate) type ImplDatum = chalk_solve::rust_ir::ImplDatum<Interner>;
+pub(crate) type OpaqueTyDatum = chalk_solve::rust_ir::OpaqueTyDatum<Interner>;
+
+pub(crate) type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
+pub(crate) type TraitId = chalk_ir::TraitId<Interner>;
+pub(crate) type AdtId = chalk_ir::AdtId<Interner>;
+pub(crate) type ImplId = chalk_ir::ImplId<Interner>;
+pub(crate) type AssociatedTyValueId = chalk_solve::rust_ir::AssociatedTyValueId<Interner>;
+pub(crate) type AssociatedTyValue = chalk_solve::rust_ir::AssociatedTyValue<Interner>;
+pub(crate) type FnDefDatum = chalk_solve::rust_ir::FnDefDatum<Interner>;
+pub(crate) type Variances = chalk_ir::Variances<Interner>;
 
 impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
@@ -82,7 +79,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         binders: &CanonicalVarKinds<Interner>,
     ) -> Vec<ImplId> {
         debug!("impls_for_trait {:?}", trait_id);
-        let trait_: hir_def::TraitId = from_chalk(self.db, trait_id);
+        let trait_: hir_def::TraitId = from_chalk_trait_id(trait_id);
 
         let ty: Ty = parameters[0].assert_ty_ref(&Interner).clone();
 
@@ -101,7 +98,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
             None
         }
 
-        let self_ty_fp = TyFingerprint::for_impl(&ty);
+        let self_ty_fp = TyFingerprint::for_trait_impl(&ty);
         let fps: &[TyFingerprint] = match binder_kind(&ty, binders) {
             Some(chalk_ir::TyVariableKind::Integer) => &ALL_INT_FPS,
             Some(chalk_ir::TyVariableKind::Float) => &ALL_FLOAT_FPS,
@@ -164,7 +161,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
             Some(LangItemTarget::TraitId(trait_)) => trait_,
             _ => return None,
         };
-        Some(trait_.to_chalk(self.db))
+        Some(to_chalk_trait_id(trait_))
     }
 
     fn program_clauses_for_env(
@@ -311,7 +308,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     }
 
     fn trait_name(&self, trait_id: chalk_ir::TraitId<Interner>) -> String {
-        let id = from_chalk(self.db, trait_id);
+        let id = from_chalk_trait_id(trait_id);
         self.db.trait_data(id).name.to_string()
     }
     fn adt_name(&self, chalk_ir::AdtId(adt_id): AdtId) -> String {
@@ -416,7 +413,7 @@ pub(crate) fn trait_datum_query(
     trait_id: TraitId,
 ) -> Arc<TraitDatum> {
     debug!("trait_datum {:?}", trait_id);
-    let trait_: hir_def::TraitId = from_chalk(db, trait_id);
+    let trait_ = from_chalk_trait_id(trait_id);
     let trait_data = db.trait_data(trait_);
     debug!("trait {:?} = {:?}", trait_id, trait_data.name);
     let generic_params = generics(db.upcast(), trait_.into());
@@ -679,38 +676,65 @@ pub(crate) fn adt_variance_query(
     )
 }
 
-impl From<FnDefId> for crate::db::InternedCallableDefId {
-    fn from(fn_def_id: FnDefId) -> Self {
-        InternKey::from_intern_id(fn_def_id.0)
-    }
-}
-
-impl From<crate::db::InternedCallableDefId> for FnDefId {
-    fn from(callable_def_id: crate::db::InternedCallableDefId) -> Self {
-        chalk_ir::FnDefId(callable_def_id.as_intern_id())
-    }
-}
-
-impl From<OpaqueTyId> for crate::db::InternedOpaqueTyId {
-    fn from(id: OpaqueTyId) -> Self {
-        InternKey::from_intern_id(id.0)
-    }
-}
-
-impl From<crate::db::InternedOpaqueTyId> for OpaqueTyId {
-    fn from(id: crate::db::InternedOpaqueTyId) -> Self {
-        chalk_ir::OpaqueTyId(id.as_intern_id())
-    }
-}
-
-impl From<chalk_ir::ClosureId<Interner>> for crate::db::InternedClosureId {
-    fn from(id: chalk_ir::ClosureId<Interner>) -> Self {
-        Self::from_intern_id(id.0)
-    }
+pub(super) fn convert_where_clauses(
+    db: &dyn HirDatabase,
+    def: GenericDefId,
+    substs: &Substitution,
+) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
+    let generic_predicates = db.generic_predicates(def);
+    let mut result = Vec::with_capacity(generic_predicates.len());
+    for pred in generic_predicates.iter() {
+        result.push(pred.clone().substitute(&Interner, substs));
+    }
+    result
 }
 
-impl From<crate::db::InternedClosureId> for chalk_ir::ClosureId<Interner> {
-    fn from(id: crate::db::InternedClosureId) -> Self {
-        chalk_ir::ClosureId(id.as_intern_id())
+pub(super) fn generic_predicate_to_inline_bound(
+    db: &dyn HirDatabase,
+    pred: &QuantifiedWhereClause,
+    self_ty: &Ty,
+) -> Option<chalk_ir::Binders<rust_ir::InlineBound<Interner>>> {
+    // An InlineBound is like a GenericPredicate, except the self type is left out.
+    // We don't have a special type for this, but Chalk does.
+    let self_ty_shifted_in = self_ty.clone().shifted_in_from(&Interner, DebruijnIndex::ONE);
+    let (pred, binders) = pred.as_ref().into_value_and_skipped_binders();
+    match pred {
+        WhereClause::Implemented(trait_ref) => {
+            if trait_ref.self_type_parameter(&Interner) != self_ty_shifted_in {
+                // we can only convert predicates back to type bounds if they
+                // have the expected self type
+                return None;
+            }
+            let args_no_self = trait_ref.substitution.as_slice(&Interner)[1..]
+                .iter()
+                .map(|ty| ty.clone().cast(&Interner))
+                .collect();
+            let trait_bound = rust_ir::TraitBound { trait_id: trait_ref.trait_id, args_no_self };
+            Some(chalk_ir::Binders::new(binders, rust_ir::InlineBound::TraitBound(trait_bound)))
+        }
+        WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
+            if projection_ty.self_type_parameter(&Interner) != self_ty_shifted_in {
+                return None;
+            }
+            let trait_ = projection_ty.trait_(db);
+            let args_no_self = projection_ty.substitution.as_slice(&Interner)[1..]
+                .iter()
+                .map(|ty| ty.clone().cast(&Interner))
+                .collect();
+            let alias_eq_bound = rust_ir::AliasEqBound {
+                value: ty.clone(),
+                trait_bound: rust_ir::TraitBound {
+                    trait_id: to_chalk_trait_id(trait_),
+                    args_no_self,
+                },
+                associated_ty_id: projection_ty.associated_ty_id,
+                parameters: Vec::new(), // FIXME we don't support generic associated types yet
+            };
+            Some(chalk_ir::Binders::new(
+                binders,
+                rust_ir::InlineBound::AliasEqBound(alias_eq_bound),
+            ))
+        }
+        _ => None,
     }
 }
diff --git a/crates/hir_ty/src/chalk_ext.rs b/crates/hir_ty/src/chalk_ext.rs
index 28ed3aac6..8c4542956 100644
--- a/crates/hir_ty/src/chalk_ext.rs
+++ b/crates/hir_ty/src/chalk_ext.rs
@@ -75,7 +75,7 @@ impl TyExt for Ty {
     }
     fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)> {
         match self.kind(&Interner) {
-            TyKind::Ref(mutability, lifetime, ty) => Some((ty, *lifetime, *mutability)),
+            TyKind::Ref(mutability, lifetime, ty) => Some((ty, lifetime.clone(), *mutability)),
             _ => None,
         }
     }
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index 326c20240..1690926ad 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -1,4 +1,5 @@
-//! FIXME: write short doc here
+//! The home of `HirDatabase`, which is the Salsa database containing all the
+//! type inference-related queries.
 
 use std::sync::Arc;
 
@@ -10,9 +11,9 @@ use hir_def::{
 use la_arena::ArenaMap;
 
 use crate::{
+    chalk_db,
     method_resolution::{InherentImpls, TraitImpls},
-    traits::chalk,
-    Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, PolyFnSig,
+    Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, Interner, PolyFnSig,
     QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId,
 };
 use hir_expand::name::Name;
@@ -94,33 +95,38 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
     #[salsa::interned]
     fn intern_closure(&self, id: (DefWithBodyId, ExprId)) -> InternedClosureId;
 
-    #[salsa::invoke(chalk::associated_ty_data_query)]
-    fn associated_ty_data(&self, id: chalk::AssocTypeId) -> Arc<chalk::AssociatedTyDatum>;
+    #[salsa::invoke(chalk_db::associated_ty_data_query)]
+    fn associated_ty_data(&self, id: chalk_db::AssocTypeId) -> Arc<chalk_db::AssociatedTyDatum>;
 
-    #[salsa::invoke(chalk::trait_datum_query)]
-    fn trait_datum(&self, krate: CrateId, trait_id: chalk::TraitId) -> Arc<chalk::TraitDatum>;
+    #[salsa::invoke(chalk_db::trait_datum_query)]
+    fn trait_datum(&self, krate: CrateId, trait_id: chalk_db::TraitId)
+        -> Arc<chalk_db::TraitDatum>;
 
-    #[salsa::invoke(chalk::struct_datum_query)]
-    fn struct_datum(&self, krate: CrateId, struct_id: chalk::AdtId) -> Arc<chalk::StructDatum>;
+    #[salsa::invoke(chalk_db::struct_datum_query)]
+    fn struct_datum(
+        &self,
+        krate: CrateId,
+        struct_id: chalk_db::AdtId,
+    ) -> Arc<chalk_db::StructDatum>;
 
-    #[salsa::invoke(crate::traits::chalk::impl_datum_query)]
-    fn impl_datum(&self, krate: CrateId, impl_id: chalk::ImplId) -> Arc<chalk::ImplDatum>;
+    #[salsa::invoke(chalk_db::impl_datum_query)]
+    fn impl_datum(&self, krate: CrateId, impl_id: chalk_db::ImplId) -> Arc<chalk_db::ImplDatum>;
 
-    #[salsa::invoke(crate::traits::chalk::fn_def_datum_query)]
-    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> Arc<chalk::FnDefDatum>;
+    #[salsa::invoke(chalk_db::fn_def_datum_query)]
+    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> Arc<chalk_db::FnDefDatum>;
 
-    #[salsa::invoke(crate::traits::chalk::fn_def_variance_query)]
-    fn fn_def_variance(&self, krate: CrateId, fn_def_id: FnDefId) -> chalk::Variances;
+    #[salsa::invoke(chalk_db::fn_def_variance_query)]
+    fn fn_def_variance(&self, krate: CrateId, fn_def_id: FnDefId) -> chalk_db::Variances;
 
-    #[salsa::invoke(crate::traits::chalk::adt_variance_query)]
-    fn adt_variance(&self, krate: CrateId, adt_id: chalk::AdtId) -> chalk::Variances;
+    #[salsa::invoke(chalk_db::adt_variance_query)]
+    fn adt_variance(&self, krate: CrateId, adt_id: chalk_db::AdtId) -> chalk_db::Variances;
 
-    #[salsa::invoke(crate::traits::chalk::associated_ty_value_query)]
+    #[salsa::invoke(chalk_db::associated_ty_value_query)]
     fn associated_ty_value(
         &self,
         krate: CrateId,
-        id: chalk::AssociatedTyValueId,
-    ) -> Arc<chalk::AssociatedTyValue>;
+        id: chalk_db::AssociatedTyValueId,
+    ) -> Arc<chalk_db::AssociatedTyValue>;
 
     #[salsa::invoke(crate::traits::trait_solve_query)]
     fn trait_solve(
@@ -129,12 +135,12 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
         goal: crate::Canonical<crate::InEnvironment<crate::DomainGoal>>,
     ) -> Option<crate::Solution>;
 
-    #[salsa::invoke(crate::traits::chalk::program_clauses_for_chalk_env_query)]
+    #[salsa::invoke(chalk_db::program_clauses_for_chalk_env_query)]
     fn program_clauses_for_chalk_env(
         &self,
         krate: CrateId,
-        env: chalk_ir::Environment<chalk::Interner>,
-    ) -> chalk_ir::ProgramClauses<chalk::Interner>;
+        env: chalk_ir::Environment<Interner>,
+    ) -> chalk_ir::ProgramClauses<Interner>;
 }
 
 fn infer_wait(db: &dyn HirDatabase, def: DefWithBodyId) -> Arc<InferenceResult> {
diff --git a/crates/hir_ty/src/diagnostics.rs b/crates/hir_ty/src/diagnostics.rs
index 86f937e1d..84fc8ce14 100644
--- a/crates/hir_ty/src/diagnostics.rs
+++ b/crates/hir_ty/src/diagnostics.rs
@@ -1,4 +1,4 @@
-//! FIXME: write short doc here
+//! Type inference-based diagnostics.
 mod expr;
 mod match_check;
 mod unsafe_check;
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index d7a3977e5..e7c9dabc2 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -1,4 +1,6 @@
-//! FIXME: write short doc here
+//! The `HirDisplay` trait, which serves two purposes: Turning various bits from
+//! HIR back into source code, and just displaying them for debugging/testing
+//! purposes.
 
 use std::{
     array,
@@ -20,11 +22,11 @@ use hir_expand::name::Name;
 
 use crate::{
     const_from_placeholder_idx, db::HirDatabase, from_assoc_type_id, from_foreign_def_id,
-    from_placeholder_idx, lt_from_placeholder_idx, primitive, subst_prefix, to_assoc_type_id,
-    traits::chalk::from_chalk, utils::generics, AdtId, AliasEq, AliasTy, CallableDefId,
-    CallableSig, Const, ConstValue, DomainGoal, GenericArg, ImplTraitId, Interner, Lifetime,
-    LifetimeData, LifetimeOutlives, Mutability, OpaqueTy, ProjectionTy, ProjectionTyExt,
-    QuantifiedWhereClause, Scalar, TraitRef, TraitRefExt, Ty, TyExt, TyKind, WhereClause,
+    from_placeholder_idx, lt_from_placeholder_idx, mapping::from_chalk, primitive, subst_prefix,
+    to_assoc_type_id, utils::generics, AdtId, AliasEq, AliasTy, CallableDefId, CallableSig, Const,
+    ConstValue, DomainGoal, GenericArg, ImplTraitId, Interner, Lifetime, LifetimeData,
+    LifetimeOutlives, Mutability, OpaqueTy, ProjectionTy, ProjectionTyExt, QuantifiedWhereClause,
+    Scalar, TraitRef, TraitRefExt, Ty, TyExt, TyKind, WhereClause,
 };
 
 pub struct HirFormatter<'a> {
@@ -265,7 +267,7 @@ impl HirDisplay for ProjectionTy {
         write!(f, " as {}", trait_.name)?;
         if self.substitution.len(&Interner) > 1 {
             write!(f, "<")?;
-            f.write_joined(&self.substitution.interned()[1..], ", ")?;
+            f.write_joined(&self.substitution.as_slice(&Interner)[1..], ", ")?;
             write!(f, ">")?;
         }
         write!(f, ">::{}", f.db.type_alias_data(from_assoc_type_id(self.associated_ty_id)).name)?;
@@ -416,7 +418,7 @@ impl HirDisplay for Ty {
                     write!(f, ",)")?;
                 } else {
                     write!(f, "(")?;
-                    f.write_joined(&*substs.interned(), ", ")?;
+                    f.write_joined(&*substs.as_slice(&Interner), ", ")?;
                     write!(f, ")")?;
                 }
             }
@@ -444,7 +446,7 @@ impl HirDisplay for Ty {
                     // 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(&parameters.interned()[..total_len], ", ")?;
+                        f.write_joined(&parameters.as_slice(&Interner)[..total_len], ", ")?;
                         write!(f, ">")?;
                     }
                 }
@@ -491,7 +493,7 @@ impl HirDisplay for Ty {
                             .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
                             .filter(|defaults| !defaults.is_empty())
                         {
-                            None => parameters.interned().as_ref(),
+                            None => parameters.as_slice(&Interner),
                             Some(default_parameters) => {
                                 let mut default_from = 0;
                                 for (i, parameter) in parameters.iter(&Interner).enumerate() {
@@ -515,11 +517,11 @@ impl HirDisplay for Ty {
                                         }
                                     }
                                 }
-                                &parameters.interned()[0..default_from]
+                                &parameters.as_slice(&Interner)[0..default_from]
                             }
                         }
                     } else {
-                        parameters.interned().as_ref()
+                        parameters.as_slice(&Interner)
                     };
                     if !parameters_to_write.is_empty() {
                         write!(f, "<")?;
@@ -542,7 +544,7 @@ impl HirDisplay for Ty {
                     write!(f, "{}::{}", trait_.name, type_alias_data.name)?;
                     if parameters.len(&Interner) > 0 {
                         write!(f, "<")?;
-                        f.write_joined(&*parameters.interned(), ", ")?;
+                        f.write_joined(&*parameters.as_slice(&Interner), ", ")?;
                         write!(f, ">")?;
                     }
                 } else {
@@ -749,13 +751,13 @@ fn write_bounds_like_dyn_trait(
                 // 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_).name)?;
-                if let [_, params @ ..] = &*trait_ref.substitution.interned().as_slice() {
+                if let [_, params @ ..] = &*trait_ref.substitution.as_slice(&Interner) {
                     if is_fn_trait {
                         if let Some(args) =
                             params.first().and_then(|it| it.assert_ty_ref(&Interner).as_tuple())
                         {
                             write!(f, "(")?;
-                            f.write_joined(&*args.interned(), ", ")?;
+                            f.write_joined(args.as_slice(&Interner), ", ")?;
                             write!(f, ")")?;
                         }
                     } else if !params.is_empty() {
@@ -814,7 +816,7 @@ fn fmt_trait_ref(tr: &TraitRef, f: &mut HirFormatter, use_as: bool) -> Result<()
     write!(f, "{}", f.db.trait_data(tr.hir_trait_id()).name)?;
     if tr.substitution.len(&Interner) > 1 {
         write!(f, "<")?;
-        f.write_joined(&tr.substitution.interned()[1..], ", ")?;
+        f.write_joined(&tr.substitution.as_slice(&Interner)[1..], ", ")?;
         write!(f, ">")?;
     }
     Ok(())
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index cbbfa8b5c..50497eecb 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -17,10 +17,11 @@ use syntax::ast::RangeOp;
 use crate::{
     autoderef, dummy_usize_const,
     lower::lower_to_chalk_mutability,
+    mapping::from_chalk,
     method_resolution, op,
     primitive::{self, UintTy},
     static_lifetime, to_chalk_trait_id,
-    traits::{chalk::from_chalk, FnTrait},
+    traits::FnTrait,
     utils::{generics, Generics},
     AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, InEnvironment, Interner,
     ProjectionTyExt, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
@@ -462,7 +463,11 @@ impl<'a> InferenceContext<'a> {
                     };
                     match canonicalized.decanonicalize_ty(derefed_ty.value).kind(&Interner) {
                         TyKind::Tuple(_, substs) => name.as_tuple_index().and_then(|idx| {
-                            substs.interned().get(idx).map(|a| a.assert_ty_ref(&Interner)).cloned()
+                            substs
+                                .as_slice(&Interner)
+                                .get(idx)
+                                .map(|a| a.assert_ty_ref(&Interner))
+                                .cloned()
                         }),
                         TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), parameters) => {
                             let local_id = self.db.struct_data(*s).variant_data.field(name)?;
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index a41e8e116..aea354cde 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -122,7 +122,7 @@ impl<'a> InferenceContext<'a> {
         let ty = match &body[pat] {
             &Pat::Tuple { ref args, ellipsis } => {
                 let expectations = match expected.as_tuple() {
-                    Some(parameters) => &*parameters.interned().as_slice(),
+                    Some(parameters) => &*parameters.as_slice(&Interner),
                     _ => &[],
                 };
 
@@ -242,7 +242,7 @@ impl<'a> InferenceContext<'a> {
                     let (inner_ty, alloc_ty) = match expected.as_adt() {
                         Some((adt, subst)) if adt == box_adt => (
                             subst.at(&Interner, 0).assert_ty_ref(&Interner).clone(),
-                            subst.interned().get(1).and_then(|a| a.ty(&Interner).cloned()),
+                            subst.as_slice(&Interner).get(1).and_then(|a| a.ty(&Interner).cloned()),
                         ),
                         _ => (self.result.standard_types.unknown.clone(), None),
                     };
diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index f8955aa32..495282eba 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -101,7 +101,7 @@ impl<'a> InferenceContext<'a> {
         let substs = ctx.substs_from_path(path, typable, true);
         let ty = TyBuilder::value_ty(self.db, typable)
             .use_parent_substs(&parent_substs)
-            .fill(substs.interned()[parent_substs.len(&Interner)..].iter().cloned())
+            .fill(substs.as_slice(&Interner)[parent_substs.len(&Interner)..].iter().cloned())
             .build();
         Some(ty)
     }
diff --git a/crates/hir_ty/src/traits/chalk/interner.rs b/crates/hir_ty/src/interner.rs
index bd9395b7e..a1656115d 100644
--- a/crates/hir_ty/src/traits/chalk/interner.rs
+++ b/crates/hir_ty/src/interner.rs
@@ -1,61 +1,83 @@
 //! Implementation of the Chalk `Interner` trait, which allows customizing the
 //! representation of the various objects Chalk deals with (types, goals etc.).
 
-use super::tls;
+use crate::{chalk_db, tls, GenericArg};
 use base_db::salsa::InternId;
-use chalk_ir::{GenericArg, Goal, GoalData};
-use hir_def::TypeAliasId;
+use chalk_ir::{Goal, GoalData};
+use hir_def::{
+    intern::{impl_internable, InternStorage, Internable, Interned},
+    TypeAliasId,
+};
 use smallvec::SmallVec;
 use std::{fmt, sync::Arc};
 
 #[derive(Debug, Copy, Clone, Hash, PartialOrd, Ord, PartialEq, Eq)]
 pub struct Interner;
 
-pub(crate) type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
-pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
-pub(crate) type TraitId = chalk_ir::TraitId<Interner>;
-pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
-pub(crate) type AdtId = chalk_ir::AdtId<Interner>;
-pub(crate) type StructDatum = chalk_solve::rust_ir::AdtDatum<Interner>;
-pub(crate) type ImplId = chalk_ir::ImplId<Interner>;
-pub(crate) type ImplDatum = chalk_solve::rust_ir::ImplDatum<Interner>;
-pub(crate) type AssociatedTyValueId = chalk_solve::rust_ir::AssociatedTyValueId<Interner>;
-pub(crate) type AssociatedTyValue = chalk_solve::rust_ir::AssociatedTyValue<Interner>;
-pub(crate) type FnDefDatum = chalk_solve::rust_ir::FnDefDatum<Interner>;
-pub(crate) type OpaqueTyId = chalk_ir::OpaqueTyId<Interner>;
-pub(crate) type OpaqueTyDatum = chalk_solve::rust_ir::OpaqueTyDatum<Interner>;
-pub(crate) type Variances = chalk_ir::Variances<Interner>;
+#[derive(PartialEq, Eq, Hash, Debug)]
+pub struct InternedWrapper<T>(T);
+
+impl<T> std::ops::Deref for InternedWrapper<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl_internable!(
+    InternedWrapper<Vec<chalk_ir::VariableKind<Interner>>>,
+    InternedWrapper<SmallVec<[GenericArg; 2]>>,
+    InternedWrapper<chalk_ir::TyData<Interner>>,
+    InternedWrapper<chalk_ir::LifetimeData<Interner>>,
+    InternedWrapper<chalk_ir::ConstData<Interner>>,
+    InternedWrapper<Vec<chalk_ir::CanonicalVarKind<Interner>>>,
+    InternedWrapper<Vec<chalk_ir::ProgramClause<Interner>>>,
+    InternedWrapper<Vec<chalk_ir::QuantifiedWhereClause<Interner>>>,
+    InternedWrapper<Vec<chalk_ir::Variance>>,
+);
 
 impl chalk_ir::interner::Interner for Interner {
-    type InternedType = Arc<chalk_ir::TyData<Self>>;
-    type InternedLifetime = chalk_ir::LifetimeData<Self>;
-    type InternedConst = Arc<chalk_ir::ConstData<Self>>;
+    type InternedType = Interned<InternedWrapper<chalk_ir::TyData<Interner>>>;
+    type InternedLifetime = Interned<InternedWrapper<chalk_ir::LifetimeData<Self>>>;
+    type InternedConst = Interned<InternedWrapper<chalk_ir::ConstData<Self>>>;
     type InternedConcreteConst = ();
     type InternedGenericArg = chalk_ir::GenericArgData<Self>;
     type InternedGoal = Arc<GoalData<Self>>;
     type InternedGoals = Vec<Goal<Self>>;
-    type InternedSubstitution = SmallVec<[GenericArg<Self>; 2]>;
-    type InternedProgramClause = Arc<chalk_ir::ProgramClauseData<Self>>;
-    type InternedProgramClauses = Arc<[chalk_ir::ProgramClause<Self>]>;
-    type InternedQuantifiedWhereClauses = Vec<chalk_ir::QuantifiedWhereClause<Self>>;
-    type InternedVariableKinds = Vec<chalk_ir::VariableKind<Self>>;
-    type InternedCanonicalVarKinds = Vec<chalk_ir::CanonicalVarKind<Self>>;
+    type InternedSubstitution = Interned<InternedWrapper<SmallVec<[GenericArg; 2]>>>;
+    type InternedProgramClause = chalk_ir::ProgramClauseData<Self>;
+    type InternedProgramClauses = Interned<InternedWrapper<Vec<chalk_ir::ProgramClause<Self>>>>;
+    type InternedQuantifiedWhereClauses =
+        Interned<InternedWrapper<Vec<chalk_ir::QuantifiedWhereClause<Self>>>>;
+    type InternedVariableKinds = Interned<InternedWrapper<Vec<chalk_ir::VariableKind<Interner>>>>;
+    type InternedCanonicalVarKinds =
+        Interned<InternedWrapper<Vec<chalk_ir::CanonicalVarKind<Self>>>>;
     type InternedConstraints = Vec<chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>>;
-    type InternedVariances = Arc<[chalk_ir::Variance]>;
+    type InternedVariances = Interned<InternedWrapper<Vec<chalk_ir::Variance>>>;
     type DefId = InternId;
     type InternedAdtId = hir_def::AdtId;
     type Identifier = TypeAliasId;
     type FnAbi = ();
 
-    fn debug_adt_id(type_kind_id: AdtId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_adt_id(
+        type_kind_id: chalk_db::AdtId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_struct_id(type_kind_id, fmt)))
     }
 
-    fn debug_trait_id(type_kind_id: TraitId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_trait_id(
+        type_kind_id: chalk_db::TraitId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_trait_id(type_kind_id, fmt)))
     }
 
-    fn debug_assoc_type_id(id: AssocTypeId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_assoc_type_id(
+        id: chalk_db::AssocTypeId,
+        fmt: &mut fmt::Formatter<'_>,
+    ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_assoc_type_id(id, fmt)))
     }
 
@@ -99,7 +121,7 @@ impl chalk_ir::interner::Interner for Interner {
     }
 
     fn debug_generic_arg(
-        parameter: &GenericArg<Interner>,
+        parameter: &GenericArg,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_generic_arg(parameter, fmt)))
@@ -194,30 +216,30 @@ impl chalk_ir::interner::Interner for Interner {
 
     fn intern_ty(&self, kind: chalk_ir::TyKind<Self>) -> Self::InternedType {
         let flags = kind.compute_flags(self);
-        Arc::new(chalk_ir::TyData { kind, flags })
+        Interned::new(InternedWrapper(chalk_ir::TyData { kind, flags }))
     }
 
     fn ty_data<'a>(&self, ty: &'a Self::InternedType) -> &'a chalk_ir::TyData<Self> {
-        ty
+        &ty.0
     }
 
     fn intern_lifetime(&self, lifetime: chalk_ir::LifetimeData<Self>) -> Self::InternedLifetime {
-        lifetime
+        Interned::new(InternedWrapper(lifetime))
     }
 
     fn lifetime_data<'a>(
         &self,
         lifetime: &'a Self::InternedLifetime,
     ) -> &'a chalk_ir::LifetimeData<Self> {
-        lifetime
+        &lifetime.0
     }
 
     fn intern_const(&self, constant: chalk_ir::ConstData<Self>) -> Self::InternedConst {
-        Arc::new(constant)
+        Interned::new(InternedWrapper(constant))
     }
 
     fn const_data<'a>(&self, constant: &'a Self::InternedConst) -> &'a chalk_ir::ConstData<Self> {
-        constant
+        &constant.0
     }
 
     fn const_eq(
@@ -264,23 +286,23 @@ impl chalk_ir::interner::Interner for Interner {
 
     fn intern_substitution<E>(
         &self,
-        data: impl IntoIterator<Item = Result<GenericArg<Self>, E>>,
+        data: impl IntoIterator<Item = Result<GenericArg, E>>,
     ) -> Result<Self::InternedSubstitution, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn substitution_data<'a>(
         &self,
         substitution: &'a Self::InternedSubstitution,
-    ) -> &'a [GenericArg<Self>] {
-        substitution
+    ) -> &'a [GenericArg] {
+        &substitution.as_ref().0
     }
 
     fn intern_program_clause(
         &self,
         data: chalk_ir::ProgramClauseData<Self>,
     ) -> Self::InternedProgramClause {
-        Arc::new(data)
+        data
     }
 
     fn program_clause_data<'a>(
@@ -294,7 +316,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         data: impl IntoIterator<Item = Result<chalk_ir::ProgramClause<Self>, E>>,
     ) -> Result<Self::InternedProgramClauses, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn program_clauses_data<'a>(
@@ -308,7 +330,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         data: impl IntoIterator<Item = Result<chalk_ir::QuantifiedWhereClause<Self>, E>>,
     ) -> Result<Self::InternedQuantifiedWhereClauses, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn quantified_where_clauses_data<'a>(
@@ -322,21 +344,21 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         data: impl IntoIterator<Item = Result<chalk_ir::VariableKind<Self>, E>>,
     ) -> Result<Self::InternedVariableKinds, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn variable_kinds_data<'a>(
         &self,
         parameter_kinds: &'a Self::InternedVariableKinds,
     ) -> &'a [chalk_ir::VariableKind<Self>] {
-        &parameter_kinds
+        &parameter_kinds.as_ref().0
     }
 
     fn intern_canonical_var_kinds<E>(
         &self,
         data: impl IntoIterator<Item = Result<chalk_ir::CanonicalVarKind<Self>, E>>,
     ) -> Result<Self::InternedCanonicalVarKinds, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn canonical_var_kinds_data<'a>(
@@ -376,7 +398,7 @@ impl chalk_ir::interner::Interner for Interner {
         &self,
         data: impl IntoIterator<Item = Result<chalk_ir::Variance, E>>,
     ) -> Result<Self::InternedVariances, E> {
-        data.into_iter().collect()
+        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
     fn variances_data<'a>(
@@ -390,3 +412,12 @@ impl chalk_ir::interner::Interner for Interner {
 impl chalk_ir::interner::HasInterner for Interner {
     type Interner = Self;
 }
+
+#[macro_export]
+macro_rules! has_interner {
+    ($t:ty) => {
+        impl HasInterner for $t {
+            type Interner = crate::Interner;
+        }
+    };
+}
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 874c95411..113234fa4 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -7,21 +7,23 @@ macro_rules! eprintln {
 }
 
 mod autoderef;
-pub mod primitive;
-pub mod traits;
-pub mod method_resolution;
-mod op;
-mod lower;
-pub(crate) mod infer;
-pub(crate) mod utils;
-mod chalk_cast;
-mod chalk_ext;
 mod builder;
+mod chalk_db;
+mod chalk_ext;
+mod infer;
+mod interner;
+mod lower;
+mod mapping;
+mod op;
+mod tls;
+mod utils;
 mod walk;
-
-pub mod display;
 pub mod db;
 pub mod diagnostics;
+pub mod display;
+pub mod method_resolution;
+pub mod primitive;
+pub mod traits;
 
 #[cfg(test)]
 mod tests;
@@ -30,16 +32,12 @@ mod test_db;
 
 use std::sync::Arc;
 
-use base_db::salsa;
 use chalk_ir::{
     fold::{Fold, Shift},
     interner::HasInterner,
     UintTy,
 };
-use hir_def::{
-    expr::ExprId, type_ref::Rawness, ConstParamId, LifetimeParamId, TraitId, TypeAliasId,
-    TypeParamId,
-};
+use hir_def::{expr::ExprId, type_ref::Rawness, TypeParamId};
 
 use crate::{db::HirDatabase, display::HirDisplay, utils::generics};
 
@@ -47,11 +45,17 @@ pub use autoderef::autoderef;
 pub use builder::TyBuilder;
 pub use chalk_ext::*;
 pub use infer::{could_unify, InferenceResult};
+pub use interner::Interner;
 pub use lower::{
     associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
     TyDefId, TyLoweringContext, ValueTyDefId,
 };
-pub use traits::{chalk::Interner, TraitEnvironment};
+pub use mapping::{
+    const_from_placeholder_idx, from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id,
+    from_placeholder_idx, lt_from_placeholder_idx, to_assoc_type_id, to_chalk_trait_id,
+    to_foreign_def_id, to_placeholder_idx,
+};
+pub use traits::TraitEnvironment;
 pub use walk::TypeWalk;
 
 pub use chalk_ir::{
@@ -94,6 +98,10 @@ pub type ConstValue = chalk_ir::ConstValue<Interner>;
 pub type ConcreteConst = chalk_ir::ConcreteConst<Interner>;
 
 pub type ChalkTraitId = chalk_ir::TraitId<Interner>;
+pub type TraitRef = chalk_ir::TraitRef<Interner>;
+pub type QuantifiedWhereClause = Binders<WhereClause>;
+pub type QuantifiedWhereClauses = chalk_ir::QuantifiedWhereClauses<Interner>;
+pub type Canonical<T> = chalk_ir::Canonical<T>;
 
 pub type FnSig = chalk_ir::FnSig<Interner>;
 
@@ -109,7 +117,7 @@ pub type WhereClause = chalk_ir::WhereClause<Interner>;
 pub fn subst_prefix(s: &Substitution, n: usize) -> Substitution {
     Substitution::from_iter(
         &Interner,
-        s.interned()[..std::cmp::min(s.len(&Interner), n)].iter().cloned(),
+        s.as_slice(&Interner)[..std::cmp::min(s.len(&Interner), n)].iter().cloned(),
     )
 }
 
@@ -118,14 +126,14 @@ pub fn param_idx(db: &dyn HirDatabase, id: TypeParamId) -> Option<usize> {
     generics(db.upcast(), id.parent).param_idx(id)
 }
 
-pub fn wrap_empty_binders<T>(value: T) -> Binders<T>
+pub(crate) fn wrap_empty_binders<T>(value: T) -> Binders<T>
 where
     T: Fold<Interner, Result = T> + HasInterner<Interner = Interner>,
 {
     Binders::empty(&Interner, value.shifted_in_from(&Interner, DebruijnIndex::ONE))
 }
 
-pub fn make_only_type_binders<T: HasInterner<Interner = Interner>>(
+pub(crate) fn make_only_type_binders<T: HasInterner<Interner = Interner>>(
     num_vars: usize,
     value: T,
 ) -> Binders<T> {
@@ -153,14 +161,6 @@ pub fn make_canonical<T: HasInterner<Interner = Interner>>(
     Canonical { value, binders: chalk_ir::CanonicalVarKinds::from_iter(&Interner, kinds) }
 }
 
-pub type TraitRef = chalk_ir::TraitRef<Interner>;
-
-pub type QuantifiedWhereClause = Binders<WhereClause>;
-
-pub type QuantifiedWhereClauses = chalk_ir::QuantifiedWhereClauses<Interner>;
-
-pub type Canonical<T> = chalk_ir::Canonical<T>;
-
 /// A function signature as seen by type inference: Several parameter types and
 /// one return type.
 #[derive(Clone, PartialEq, Eq, Debug)]
@@ -169,6 +169,8 @@ pub struct CallableSig {
     is_varargs: bool,
 }
 
+has_interner!(CallableSig);
+
 /// A polymorphic function signature.
 pub type PolyFnSig = Binders<CallableSig>;
 
@@ -187,7 +189,7 @@ impl CallableSig {
                 .shifted_out_to(&Interner, DebruijnIndex::ONE)
                 .expect("unexpected lifetime vars in fn ptr")
                 .0
-                .interned()
+                .as_slice(&Interner)
                 .iter()
                 .map(|arg| arg.assert_ty_ref(&Interner).clone())
                 .collect(),
@@ -232,61 +234,13 @@ pub struct ReturnTypeImplTraits {
     pub(crate) impl_traits: Vec<ReturnTypeImplTrait>,
 }
 
+has_interner!(ReturnTypeImplTraits);
+
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub(crate) struct ReturnTypeImplTrait {
     pub(crate) bounds: Binders<Vec<QuantifiedWhereClause>>,
 }
 
-pub fn to_foreign_def_id(id: TypeAliasId) -> ForeignDefId {
-    chalk_ir::ForeignDefId(salsa::InternKey::as_intern_id(&id))
-}
-
-pub fn from_foreign_def_id(id: ForeignDefId) -> TypeAliasId {
-    salsa::InternKey::from_intern_id(id.0)
-}
-
-pub fn to_assoc_type_id(id: TypeAliasId) -> AssocTypeId {
-    chalk_ir::AssocTypeId(salsa::InternKey::as_intern_id(&id))
-}
-
-pub fn from_assoc_type_id(id: AssocTypeId) -> TypeAliasId {
-    salsa::InternKey::from_intern_id(id.0)
-}
-
-pub fn from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> TypeParamId {
-    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
-    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
-    db.lookup_intern_type_param_id(interned_id)
-}
-
-pub fn to_placeholder_idx(db: &dyn HirDatabase, id: TypeParamId) -> PlaceholderIndex {
-    let interned_id = db.intern_type_param_id(id);
-    PlaceholderIndex {
-        ui: chalk_ir::UniverseIndex::ROOT,
-        idx: salsa::InternKey::as_intern_id(&interned_id).as_usize(),
-    }
-}
-
-pub fn lt_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> LifetimeParamId {
-    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
-    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
-    db.lookup_intern_lifetime_param_id(interned_id)
-}
-
-pub fn const_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> ConstParamId {
-    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
-    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
-    db.lookup_intern_const_param_id(interned_id)
-}
-
-pub fn to_chalk_trait_id(id: TraitId) -> ChalkTraitId {
-    chalk_ir::TraitId(salsa::InternKey::as_intern_id(&id))
-}
-
-pub fn from_chalk_trait_id(id: ChalkTraitId) -> TraitId {
-    salsa::InternKey::from_intern_id(id.0)
-}
-
 pub fn static_lifetime() -> Lifetime {
     LifetimeData::Static.intern(&Interner)
 }
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 8a22d9ea3..a035686bc 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -27,13 +27,14 @@ use stdx::impl_from;
 
 use crate::{
     db::HirDatabase,
-    dummy_usize_const, static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
-    traits::chalk::{Interner, ToChalk},
+    dummy_usize_const,
+    mapping::ToChalk,
+    static_lifetime, to_assoc_type_id, to_chalk_trait_id, to_placeholder_idx,
     utils::{
         all_super_trait_refs, associated_type_by_name_including_super_traits, generics, Generics,
     },
     AliasEq, AliasTy, Binders, BoundVar, CallableSig, DebruijnIndex, DynTy, FnPointer, FnSig,
-    FnSubst, ImplTraitId, OpaqueTy, PolyFnSig, ProjectionTy, QuantifiedWhereClause,
+    FnSubst, ImplTraitId, Interner, OpaqueTy, PolyFnSig, ProjectionTy, QuantifiedWhereClause,
     QuantifiedWhereClauses, ReturnTypeImplTrait, ReturnTypeImplTraits, Substitution,
     TraitEnvironment, TraitRef, TraitRefExt, Ty, TyBuilder, TyKind, WhereClause,
 };
diff --git a/crates/hir_ty/src/mapping.rs b/crates/hir_ty/src/mapping.rs
new file mode 100644
index 000000000..5e86fafe5
--- /dev/null
+++ b/crates/hir_ty/src/mapping.rs
@@ -0,0 +1,154 @@
+//! This module contains the implementations of the `ToChalk` trait, which
+//! handles conversion between our data types and their corresponding types in
+//! Chalk (in both directions); plus some helper functions for more specialized
+//! conversions.
+
+use chalk_solve::rust_ir;
+
+use base_db::salsa::{self, InternKey};
+use hir_def::{ConstParamId, LifetimeParamId, TraitId, TypeAliasId, TypeParamId};
+
+use crate::{
+    chalk_db, db::HirDatabase, AssocTypeId, CallableDefId, ChalkTraitId, FnDefId, ForeignDefId,
+    Interner, OpaqueTyId, PlaceholderIndex,
+};
+
+pub(crate) trait ToChalk {
+    type Chalk;
+    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
+    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
+}
+
+pub(crate) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
+where
+    T: ToChalk<Chalk = ChalkT>,
+{
+    T::from_chalk(db, chalk)
+}
+
+impl ToChalk for hir_def::ImplId {
+    type Chalk = chalk_db::ImplId;
+
+    fn to_chalk(self, _db: &dyn HirDatabase) -> chalk_db::ImplId {
+        chalk_ir::ImplId(self.as_intern_id())
+    }
+
+    fn from_chalk(_db: &dyn HirDatabase, impl_id: chalk_db::ImplId) -> hir_def::ImplId {
+        InternKey::from_intern_id(impl_id.0)
+    }
+}
+
+impl ToChalk for CallableDefId {
+    type Chalk = FnDefId;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> FnDefId {
+        db.intern_callable_def(self).into()
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, fn_def_id: FnDefId) -> CallableDefId {
+        db.lookup_intern_callable_def(fn_def_id.into())
+    }
+}
+
+pub(crate) struct TypeAliasAsValue(pub(crate) TypeAliasId);
+
+impl ToChalk for TypeAliasAsValue {
+    type Chalk = chalk_db::AssociatedTyValueId;
+
+    fn to_chalk(self, _db: &dyn HirDatabase) -> chalk_db::AssociatedTyValueId {
+        rust_ir::AssociatedTyValueId(self.0.as_intern_id())
+    }
+
+    fn from_chalk(
+        _db: &dyn HirDatabase,
+        assoc_ty_value_id: chalk_db::AssociatedTyValueId,
+    ) -> TypeAliasAsValue {
+        TypeAliasAsValue(TypeAliasId::from_intern_id(assoc_ty_value_id.0))
+    }
+}
+
+impl From<FnDefId> for crate::db::InternedCallableDefId {
+    fn from(fn_def_id: FnDefId) -> Self {
+        InternKey::from_intern_id(fn_def_id.0)
+    }
+}
+
+impl From<crate::db::InternedCallableDefId> for FnDefId {
+    fn from(callable_def_id: crate::db::InternedCallableDefId) -> Self {
+        chalk_ir::FnDefId(callable_def_id.as_intern_id())
+    }
+}
+
+impl From<OpaqueTyId> for crate::db::InternedOpaqueTyId {
+    fn from(id: OpaqueTyId) -> Self {
+        InternKey::from_intern_id(id.0)
+    }
+}
+
+impl From<crate::db::InternedOpaqueTyId> for OpaqueTyId {
+    fn from(id: crate::db::InternedOpaqueTyId) -> Self {
+        chalk_ir::OpaqueTyId(id.as_intern_id())
+    }
+}
+
+impl From<chalk_ir::ClosureId<Interner>> for crate::db::InternedClosureId {
+    fn from(id: chalk_ir::ClosureId<Interner>) -> Self {
+        Self::from_intern_id(id.0)
+    }
+}
+
+impl From<crate::db::InternedClosureId> for chalk_ir::ClosureId<Interner> {
+    fn from(id: crate::db::InternedClosureId) -> Self {
+        chalk_ir::ClosureId(id.as_intern_id())
+    }
+}
+
+pub fn to_foreign_def_id(id: TypeAliasId) -> ForeignDefId {
+    chalk_ir::ForeignDefId(salsa::InternKey::as_intern_id(&id))
+}
+
+pub fn from_foreign_def_id(id: ForeignDefId) -> TypeAliasId {
+    salsa::InternKey::from_intern_id(id.0)
+}
+
+pub fn to_assoc_type_id(id: TypeAliasId) -> AssocTypeId {
+    chalk_ir::AssocTypeId(salsa::InternKey::as_intern_id(&id))
+}
+
+pub fn from_assoc_type_id(id: AssocTypeId) -> TypeAliasId {
+    salsa::InternKey::from_intern_id(id.0)
+}
+
+pub fn from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> TypeParamId {
+    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
+    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
+    db.lookup_intern_type_param_id(interned_id)
+}
+
+pub fn to_placeholder_idx(db: &dyn HirDatabase, id: TypeParamId) -> PlaceholderIndex {
+    let interned_id = db.intern_type_param_id(id);
+    PlaceholderIndex {
+        ui: chalk_ir::UniverseIndex::ROOT,
+        idx: salsa::InternKey::as_intern_id(&interned_id).as_usize(),
+    }
+}
+
+pub fn lt_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> LifetimeParamId {
+    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
+    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
+    db.lookup_intern_lifetime_param_id(interned_id)
+}
+
+pub fn const_from_placeholder_idx(db: &dyn HirDatabase, idx: PlaceholderIndex) -> ConstParamId {
+    assert_eq!(idx.ui, chalk_ir::UniverseIndex::ROOT);
+    let interned_id = salsa::InternKey::from_intern_id(salsa::InternId::from(idx.idx));
+    db.lookup_intern_const_param_id(interned_id)
+}
+
+pub fn to_chalk_trait_id(id: TraitId) -> ChalkTraitId {
+    chalk_ir::TraitId(salsa::InternKey::as_intern_id(&id))
+}
+
+pub fn from_chalk_trait_id(id: ChalkTraitId) -> TraitId {
+    salsa::InternKey::from_intern_id(id.0)
+}
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index be3e4f09a..3693e3284 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -21,32 +21,36 @@ use crate::{
     primitive::{self, FloatTy, IntTy, UintTy},
     static_lifetime,
     utils::all_super_traits,
-    AdtId, Canonical, CanonicalVarKinds, DebruijnIndex, FnPointer, FnSig, ForeignDefId,
-    InEnvironment, Interner, Scalar, Substitution, TraitEnvironment, TraitRefExt, Ty, TyBuilder,
-    TyExt, TyKind,
+    AdtId, Canonical, CanonicalVarKinds, DebruijnIndex, ForeignDefId, InEnvironment, Interner,
+    Scalar, Substitution, TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyExt, TyKind,
 };
 
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum TyFingerprint {
+    // These are lang item impls:
     Str,
     Slice,
     Array,
     Never,
     RawPtr(Mutability),
     Scalar(Scalar),
+    // These can have user-defined impls:
     Adt(hir_def::AdtId),
     Dyn(TraitId),
-    Tuple(usize),
     ForeignType(ForeignDefId),
-    FnPtr(usize, FnSig),
+    // These only exist for trait impls
+    Unit,
+    Unnameable,
+    Function(u32),
 }
 
 impl TyFingerprint {
-    /// Creates a TyFingerprint for looking up an impl. Only certain types can
-    /// have impls: if we have some `struct S`, we can have an `impl S`, but not
-    /// `impl &S`. Hence, this will return `None` for reference types and such.
-    pub fn for_impl(ty: &Ty) -> Option<TyFingerprint> {
+    /// Creates a TyFingerprint for looking up an inherent impl. Only certain
+    /// types can have inherent impls: if we have some `struct S`, we can have
+    /// an `impl S`, but not `impl &S`. Hence, this will return `None` for
+    /// reference types and such.
+    pub fn for_inherent_impl(ty: &Ty) -> Option<TyFingerprint> {
         let fp = match ty.kind(&Interner) {
             TyKind::Str => TyFingerprint::Str,
             TyKind::Never => TyFingerprint::Never,
@@ -54,17 +58,52 @@ impl TyFingerprint {
             TyKind::Array(..) => TyFingerprint::Array,
             TyKind::Scalar(scalar) => TyFingerprint::Scalar(*scalar),
             TyKind::Adt(AdtId(adt), _) => TyFingerprint::Adt(*adt),
-            TyKind::Tuple(cardinality, _) => TyFingerprint::Tuple(*cardinality),
             TyKind::Raw(mutability, ..) => TyFingerprint::RawPtr(*mutability),
             TyKind::Foreign(alias_id, ..) => TyFingerprint::ForeignType(*alias_id),
-            TyKind::Function(FnPointer { sig, substitution: substs, .. }) => {
-                TyFingerprint::FnPtr(substs.0.len(&Interner) - 1, *sig)
-            }
             TyKind::Dyn(_) => ty.dyn_trait().map(|trait_| TyFingerprint::Dyn(trait_))?,
             _ => return None,
         };
         Some(fp)
     }
+
+    /// Creates a TyFingerprint for looking up a trait impl.
+    pub fn for_trait_impl(ty: &Ty) -> Option<TyFingerprint> {
+        let fp = match ty.kind(&Interner) {
+            TyKind::Str => TyFingerprint::Str,
+            TyKind::Never => TyFingerprint::Never,
+            TyKind::Slice(..) => TyFingerprint::Slice,
+            TyKind::Array(..) => TyFingerprint::Array,
+            TyKind::Scalar(scalar) => TyFingerprint::Scalar(*scalar),
+            TyKind::Adt(AdtId(adt), _) => TyFingerprint::Adt(*adt),
+            TyKind::Raw(mutability, ..) => TyFingerprint::RawPtr(*mutability),
+            TyKind::Foreign(alias_id, ..) => TyFingerprint::ForeignType(*alias_id),
+            TyKind::Dyn(_) => ty.dyn_trait().map(|trait_| TyFingerprint::Dyn(trait_))?,
+            TyKind::Ref(_, _, ty) => return TyFingerprint::for_trait_impl(ty),
+            TyKind::Tuple(_, subst) => {
+                let first_ty = subst.interned().get(0).map(|arg| arg.assert_ty_ref(&Interner));
+                if let Some(ty) = first_ty {
+                    return TyFingerprint::for_trait_impl(ty);
+                } else {
+                    TyFingerprint::Unit
+                }
+            }
+            TyKind::AssociatedType(_, _)
+            | TyKind::OpaqueType(_, _)
+            | TyKind::FnDef(_, _)
+            | TyKind::Closure(_, _)
+            | TyKind::Generator(..)
+            | TyKind::GeneratorWitness(..) => TyFingerprint::Unnameable,
+            TyKind::Function(fn_ptr) => {
+                TyFingerprint::Function(fn_ptr.substitution.0.len(&Interner) as u32)
+            }
+            TyKind::Alias(_)
+            | TyKind::Placeholder(_)
+            | TyKind::BoundVar(_)
+            | TyKind::InferenceVar(_, _)
+            | TyKind::Error => return None,
+        };
+        Some(fp)
+    }
 }
 
 pub(crate) const ALL_INT_FPS: [TyFingerprint; 12] = [
@@ -112,7 +151,7 @@ impl TraitImpls {
                         None => continue,
                     };
                     let self_ty = db.impl_self_ty(impl_id);
-                    let self_ty_fp = TyFingerprint::for_impl(self_ty.skip_binders());
+                    let self_ty_fp = TyFingerprint::for_trait_impl(self_ty.skip_binders());
                     impls
                         .map
                         .entry(target_trait)
@@ -157,10 +196,13 @@ impl TraitImpls {
     }
 
     /// Queries all trait impls for the given type.
-    pub fn for_self_ty(&self, fp: TyFingerprint) -> impl Iterator<Item = ImplId> + '_ {
+    pub fn for_self_ty_without_blanket_impls(
+        &self,
+        fp: TyFingerprint,
+    ) -> impl Iterator<Item = ImplId> + '_ {
         self.map
             .values()
-            .flat_map(move |impls| impls.get(&None).into_iter().chain(impls.get(&Some(fp))))
+            .flat_map(move |impls| impls.get(&Some(fp)).into_iter())
             .flat_map(|it| it.iter().copied())
     }
 
@@ -215,9 +257,11 @@ impl InherentImpls {
                 }
 
                 let self_ty = db.impl_self_ty(impl_id);
-                if let Some(fp) = TyFingerprint::for_impl(self_ty.skip_binders()) {
+                let fp = TyFingerprint::for_inherent_impl(self_ty.skip_binders());
+                if let Some(fp) = fp {
                     map.entry(fp).or_default().push(impl_id);
                 }
+                // `fp` should only be `None` in error cases (either erroneous code or incomplete name resolution)
             }
         }
 
@@ -228,7 +272,7 @@ impl InherentImpls {
     }
 
     pub fn for_self_ty(&self, self_ty: &Ty) -> &[ImplId] {
-        match TyFingerprint::for_impl(self_ty) {
+        match TyFingerprint::for_inherent_impl(self_ty) {
             Some(fp) => self.map.get(&fp).map(|vec| vec.as_ref()).unwrap_or(&[]),
             None => &[],
         }
@@ -609,6 +653,7 @@ fn iterate_trait_method_candidates(
                 }
             }
             known_implemented = true;
+            // FIXME: we shouldn't be ignoring the binders here
             if callback(&self_ty.value, *item) {
                 return true;
             }
diff --git a/crates/hir_ty/src/op.rs b/crates/hir_ty/src/op.rs
index 0491c5cb4..0222de2bc 100644
--- a/crates/hir_ty/src/op.rs
+++ b/crates/hir_ty/src/op.rs
@@ -9,21 +9,55 @@ pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
         BinaryOp::LogicOp(_) | BinaryOp::CmpOp(_) => TyKind::Scalar(Scalar::Bool).intern(&Interner),
         BinaryOp::Assignment { .. } => TyBuilder::unit(),
         BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => {
-            match lhs_ty.kind(&Interner) {
+            // all integer combinations are valid here
+            if matches!(
+                lhs_ty.kind(&Interner),
                 TyKind::Scalar(Scalar::Int(_))
-                | TyKind::Scalar(Scalar::Uint(_))
-                | TyKind::Scalar(Scalar::Float(_)) => lhs_ty,
-                TyKind::InferenceVar(_, TyVariableKind::Integer)
-                | TyKind::InferenceVar(_, TyVariableKind::Float) => lhs_ty,
-                _ => TyKind::Error.intern(&Interner),
+                    | TyKind::Scalar(Scalar::Uint(_))
+                    | TyKind::InferenceVar(_, TyVariableKind::Integer)
+            ) && matches!(
+                rhs_ty.kind(&Interner),
+                TyKind::Scalar(Scalar::Int(_))
+                    | TyKind::Scalar(Scalar::Uint(_))
+                    | TyKind::InferenceVar(_, TyVariableKind::Integer)
+            ) {
+                lhs_ty
+            } else {
+                TyKind::Error.intern(&Interner)
             }
         }
-        BinaryOp::ArithOp(_) => match rhs_ty.kind(&Interner) {
-            TyKind::Scalar(Scalar::Int(_))
-            | TyKind::Scalar(Scalar::Uint(_))
-            | TyKind::Scalar(Scalar::Float(_)) => rhs_ty,
-            TyKind::InferenceVar(_, TyVariableKind::Integer)
-            | TyKind::InferenceVar(_, TyVariableKind::Float) => rhs_ty,
+        BinaryOp::ArithOp(_) => match (lhs_ty.kind(&Interner), rhs_ty.kind(&Interner)) {
+            // (int, int) | (uint, uint) | (float, float)
+            (TyKind::Scalar(Scalar::Int(_)), TyKind::Scalar(Scalar::Int(_)))
+            | (TyKind::Scalar(Scalar::Uint(_)), TyKind::Scalar(Scalar::Uint(_)))
+            | (TyKind::Scalar(Scalar::Float(_)), TyKind::Scalar(Scalar::Float(_))) => rhs_ty,
+            // ({int}, int) | ({int}, uint)
+            (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Int(_)))
+            | (TyKind::InferenceVar(_, TyVariableKind::Integer), TyKind::Scalar(Scalar::Uint(_))) => {
+                rhs_ty
+            }
+            // (int, {int}) | (uint, {int})
+            (TyKind::Scalar(Scalar::Int(_)), TyKind::InferenceVar(_, TyVariableKind::Integer))
+            | (TyKind::Scalar(Scalar::Uint(_)), TyKind::InferenceVar(_, TyVariableKind::Integer)) => {
+                lhs_ty
+            }
+            // ({float} | float)
+            (TyKind::InferenceVar(_, TyVariableKind::Float), TyKind::Scalar(Scalar::Float(_))) => {
+                rhs_ty
+            }
+            // (float, {float})
+            (TyKind::Scalar(Scalar::Float(_)), TyKind::InferenceVar(_, TyVariableKind::Float)) => {
+                lhs_ty
+            }
+            // ({int}, {int}) | ({float}, {float})
+            (
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+                TyKind::InferenceVar(_, TyVariableKind::Integer),
+            )
+            | (
+                TyKind::InferenceVar(_, TyVariableKind::Float),
+                TyKind::InferenceVar(_, TyVariableKind::Float),
+            ) => rhs_ty,
             _ => TyKind::Error.intern(&Interner),
         },
     }
diff --git a/crates/hir_ty/src/primitive.rs b/crates/hir_ty/src/primitive.rs
index 2449addfb..d7f48c69a 100644
--- a/crates/hir_ty/src/primitive.rs
+++ b/crates/hir_ty/src/primitive.rs
@@ -1,7 +1,4 @@
-//! Defines primitive types, which have a couple of peculiarities:
-//!
-//! * during type inference, they can be uncertain (ie, `let x = 92;`)
-//! * they don't belong to any particular crate.
+//! A few helper functions for dealing with primitives.
 
 pub use chalk_ir::{FloatTy, IntTy, UintTy};
 pub use hir_def::builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint};
diff --git a/crates/hir_ty/src/tests/macros.rs b/crates/hir_ty/src/tests/macros.rs
index 86e3d8b86..b8e373ed8 100644
--- a/crates/hir_ty/src/tests/macros.rs
+++ b/crates/hir_ty/src/tests/macros.rs
@@ -1065,11 +1065,11 @@ fn macro_in_arm() {
         }
         "#,
         expect![[r#"
+            !0..2 '()': ()
             51..110 '{     ...  }; }': ()
             61..62 'x': u32
             65..107 'match ...     }': u32
             71..73 '()': ()
-            84..91 'unit!()': ()
             95..100 '92u32': u32
         "#]],
     );
diff --git a/crates/hir_ty/src/tests/patterns.rs b/crates/hir_ty/src/tests/patterns.rs
index 85a28e76b..f514b3efe 100644
--- a/crates/hir_ty/src/tests/patterns.rs
+++ b/crates/hir_ty/src/tests/patterns.rs
@@ -1,6 +1,6 @@
 use expect_test::expect;
 
-use super::{check_infer, check_infer_with_mismatches};
+use super::{check_infer, check_infer_with_mismatches, check_types};
 
 #[test]
 fn infer_pattern() {
@@ -825,3 +825,29 @@ fn foo(foo: Foo) {
         "#]],
     );
 }
+
+#[test]
+fn macro_pat() {
+    check_types(
+        r#"
+macro_rules! pat {
+    ($name:ident) => { Enum::Variant1($name) }
+}
+
+enum Enum {
+    Variant1(u8),
+    Variant2,
+}
+
+fn f(e: Enum) {
+    match e {
+        pat!(bind) => {
+            bind;
+          //^^^^ u8
+        }
+        Enum::Variant2 => {}
+    }
+}
+    "#,
+    )
+}
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index b69f86050..9cd9f473d 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -974,3 +974,41 @@ fn param_overrides_fn() {
         "#,
     )
 }
+
+#[test]
+fn lifetime_from_chalk_during_deref() {
+    check_types(
+        r#"
+        #[lang = "deref"]
+        pub trait Deref {
+            type Target;
+        }
+
+        struct Box<T: ?Sized> {}
+        impl<T> Deref for Box<T> {
+            type Target = T;
+
+            fn deref(&self) -> &Self::Target {
+                loop {}
+            }
+        }
+
+        trait Iterator {
+            type Item;
+        }
+
+        pub struct Iter<'a, T: 'a> {
+            inner: Box<dyn IterTrait<'a, T, Item = &'a T> + 'a>,
+        }
+
+        trait IterTrait<'a, T: 'a>: Iterator<Item = &'a T> {
+            fn clone_box(&self);
+        }
+
+        fn clone_iter<T>(s: Iter<T>) {
+            s.inner.clone_box();
+          //^^^^^^^^^^^^^^^^^^^ ()
+        }
+        "#,
+    )
+}
diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index 65b71fdfa..ffc7c8ef4 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -263,15 +263,14 @@ mod ops {
 fn infer_from_bound_1() {
     check_infer(
         r#"
-        trait Trait<T> {}
-        struct S<T>(T);
-        impl<U> Trait<U> for S<U> {}
-        fn foo<T: Trait<u32>>(t: T) {}
-        fn test() {
-            let s = S(unknown);
-            foo(s);
-        }
-        "#,
+trait Trait<T> {}
+struct S<T>(T);
+impl<U> Trait<U> for S<U> {}
+fn foo<T: Trait<u32>>(t: T) {}
+fn test() {
+    let s = S(unknown);
+    foo(s);
+}"#,
         expect![[r#"
             85..86 't': T
             91..93 '{}': ()
@@ -291,15 +290,14 @@ fn infer_from_bound_1() {
 fn infer_from_bound_2() {
     check_infer(
         r#"
-        trait Trait<T> {}
-        struct S<T>(T);
-        impl<U> Trait<U> for S<U> {}
-        fn foo<U, T: Trait<U>>(t: T) -> U {}
-        fn test() {
-            let s = S(unknown);
-            let x: u32 = foo(s);
-        }
-        "#,
+trait Trait<T> {}
+struct S<T>(T);
+impl<U> Trait<U> for S<U> {}
+fn foo<U, T: Trait<U>>(t: T) -> U {}
+fn test() {
+    let s = S(unknown);
+    let x: u32 = foo(s);
+}"#,
         expect![[r#"
             86..87 't': T
             97..99 '{}': ()
@@ -321,13 +319,12 @@ fn trait_default_method_self_bound_implements_trait() {
     cov_mark::check!(trait_self_implements_self);
     check_infer(
         r#"
-        trait Trait {
-            fn foo(&self) -> i64;
-            fn bar(&self) -> {
-                let x = self.foo();
-            }
-        }
-        "#,
+trait Trait {
+    fn foo(&self) -> i64;
+    fn bar(&self) -> {
+        let x = self.foo();
+    }
+}"#,
         expect![[r#"
             26..30 'self': &Self
             52..56 'self': &Self
@@ -343,15 +340,14 @@ fn trait_default_method_self_bound_implements_trait() {
 fn trait_default_method_self_bound_implements_super_trait() {
     check_infer(
         r#"
-        trait SuperTrait {
-            fn foo(&self) -> i64;
-        }
-        trait Trait: SuperTrait {
-            fn bar(&self) -> {
-                let x = self.foo();
-            }
-        }
-        "#,
+trait SuperTrait {
+    fn foo(&self) -> i64;
+}
+trait Trait: SuperTrait {
+    fn bar(&self) -> {
+        let x = self.foo();
+    }
+}"#,
         expect![[r#"
             31..35 'self': &Self
             85..89 'self': &Self
@@ -367,18 +363,17 @@ fn trait_default_method_self_bound_implements_super_trait() {
 fn infer_project_associated_type() {
     check_infer(
         r#"
-        trait Iterable {
-            type Item;
-        }
-        struct S;
-        impl Iterable for S { type Item = u32; }
-        fn test<T: Iterable>() {
-            let x: <S as Iterable>::Item = 1;
-            let y: <T as Iterable>::Item = no_matter;
-            let z: T::Item = no_matter;
-            let a: <T>::Item = no_matter;
-        }
-        "#,
+trait Iterable {
+    type Item;
+}
+struct S;
+impl Iterable for S { type Item = u32; }
+fn test<T: Iterable>() {
+    let x: <S as Iterable>::Item = 1;
+    let y: <T as Iterable>::Item = no_matter;
+    let z: T::Item = no_matter;
+    let a: <T>::Item = no_matter;
+}"#,
         expect![[r#"
             108..261 '{     ...ter; }': ()
             118..119 'x': u32
@@ -397,20 +392,19 @@ fn infer_project_associated_type() {
 fn infer_return_associated_type() {
     check_infer(
         r#"
-        trait Iterable {
-            type Item;
-        }
-        struct S;
-        impl Iterable for S { type Item = u32; }
-        fn foo1<T: Iterable>(t: T) -> T::Item {}
-        fn foo2<T: Iterable>(t: T) -> <T as Iterable>::Item {}
-        fn foo3<T: Iterable>(t: T) -> <T>::Item {}
-        fn test() {
-            let x = foo1(S);
-            let y = foo2(S);
-            let z = foo3(S);
-        }
-        "#,
+trait Iterable {
+    type Item;
+}
+struct S;
+impl Iterable for S { type Item = u32; }
+fn foo1<T: Iterable>(t: T) -> T::Item {}
+fn foo2<T: Iterable>(t: T) -> <T as Iterable>::Item {}
+fn foo3<T: Iterable>(t: T) -> <T>::Item {}
+fn test() {
+    let x = foo1(S);
+    let y = foo2(S);
+    let z = foo3(S);
+}"#,
         expect![[r#"
             106..107 't': T
             123..125 '{}': ()
@@ -439,13 +433,12 @@ fn infer_return_associated_type() {
 fn infer_associated_type_bound() {
     check_infer(
         r#"
-        trait Iterable {
-            type Item;
-        }
-        fn test<T: Iterable<Item=u32>>() {
-            let y: T::Item = unknown;
-        }
-        "#,
+trait Iterable {
+    type Item;
+}
+fn test<T: Iterable<Item=u32>>() {
+    let y: T::Item = unknown;
+}"#,
         expect![[r#"
             67..100 '{     ...own; }': ()
             77..78 'y': u32
@@ -458,9 +451,8 @@ fn infer_associated_type_bound() {
 fn infer_const_body() {
     check_infer(
         r#"
-        const A: u32 = 1 + 1;
-        static B: u64 = { let x = 1; x };
-        "#,
+const A: u32 = 1 + 1;
+static B: u64 = { let x = 1; x };"#,
         expect![[r#"
             15..16 '1': u32
             15..20 '1 + 1': u32
@@ -477,13 +469,12 @@ fn infer_const_body() {
 fn tuple_struct_fields() {
     check_infer(
         r#"
-        struct S(i32, u64);
-        fn test() -> u64 {
-            let a = S(4, 6);
-            let b = a.0;
-            a.1
-        }
-        "#,
+struct S(i32, u64);
+fn test() -> u64 {
+    let a = S(4, 6);
+    let b = a.0;
+    a.1
+}"#,
         expect![[r#"
             37..86 '{     ... a.1 }': u64
             47..48 'a': S
@@ -504,13 +495,12 @@ fn tuple_struct_fields() {
 fn tuple_struct_with_fn() {
     check_infer(
         r#"
-        struct S(fn(u32) -> u64);
-        fn test() -> u64 {
-            let a = S(|i| 2*i);
-            let b = a.0(4);
-            a.0(2)
-        }
-        "#,
+struct S(fn(u32) -> u64);
+fn test() -> u64 {
+    let a = S(|i| 2*i);
+    let b = a.0(4);
+    a.0(2)
+}"#,
         expect![[r#"
             43..101 '{     ...0(2) }': u64
             53..54 'a': S
@@ -949,27 +939,26 @@ fn test<T: ApplyL>(t: T) {
 fn argument_impl_trait() {
     check_infer_with_mismatches(
         r#"
-        trait Trait<T> {
-            fn foo(&self) -> T;
-            fn foo2(&self) -> i64;
-        }
-        fn bar(x: impl Trait<u16>) {}
-        struct S<T>(T);
-        impl<T> Trait<T> for S<T> {}
-
-        fn test(x: impl Trait<u64>, y: &impl Trait<u32>) {
-            x;
-            y;
-            let z = S(1);
-            bar(z);
-            x.foo();
-            y.foo();
-            z.foo();
-            x.foo2();
-            y.foo2();
-            z.foo2();
-        }
-        "#,
+trait Trait<T> {
+    fn foo(&self) -> T;
+    fn foo2(&self) -> i64;
+}
+fn bar(x: impl Trait<u16>) {}
+struct S<T>(T);
+impl<T> Trait<T> for S<T> {}
+
+fn test(x: impl Trait<u64>, y: &impl Trait<u32>) {
+    x;
+    y;
+    let z = S(1);
+    bar(z);
+    x.foo();
+    y.foo();
+    z.foo();
+    x.foo2();
+    y.foo2();
+    z.foo2();
+}"#,
         expect![[r#"
             29..33 'self': &Self
             54..58 'self': &Self
@@ -1007,30 +996,29 @@ fn argument_impl_trait() {
 fn argument_impl_trait_type_args_1() {
     check_infer_with_mismatches(
         r#"
-        trait Trait {}
-        trait Foo {
-            // this function has an implicit Self param, an explicit type param,
-            // and an implicit impl Trait param!
-            fn bar<T>(x: impl Trait) -> T { loop {} }
-        }
-        fn foo<T>(x: impl Trait) -> T { loop {} }
-        struct S;
-        impl Trait for S {}
-        struct F;
-        impl Foo for F {}
-
-        fn test() {
-            Foo::bar(S);
-            <F as Foo>::bar(S);
-            F::bar(S);
-            Foo::bar::<u32>(S);
-            <F as Foo>::bar::<u32>(S);
-
-            foo(S);
-            foo::<u32>(S);
-            foo::<u32, i32>(S); // we should ignore the extraneous i32
-        }
-        "#,
+trait Trait {}
+trait Foo {
+    // this function has an implicit Self param, an explicit type param,
+    // and an implicit impl Trait param!
+    fn bar<T>(x: impl Trait) -> T { loop {} }
+}
+fn foo<T>(x: impl Trait) -> T { loop {} }
+struct S;
+impl Trait for S {}
+struct F;
+impl Foo for F {}
+
+fn test() {
+    Foo::bar(S);
+    <F as Foo>::bar(S);
+    F::bar(S);
+    Foo::bar::<u32>(S);
+    <F as Foo>::bar::<u32>(S);
+
+    foo(S);
+    foo::<u32>(S);
+    foo::<u32, i32>(S); // we should ignore the extraneous i32
+}"#,
         expect![[r#"
             155..156 'x': impl Trait
             175..186 '{ loop {} }': T
@@ -1073,21 +1061,20 @@ fn argument_impl_trait_type_args_1() {
 fn argument_impl_trait_type_args_2() {
     check_infer_with_mismatches(
         r#"
-        trait Trait {}
-        struct S;
-        impl Trait for S {}
-        struct F<T>;
-        impl<T> F<T> {
-            fn foo<U>(self, x: impl Trait) -> (T, U) { loop {} }
-        }
+trait Trait {}
+struct S;
+impl Trait for S {}
+struct F<T>;
+impl<T> F<T> {
+    fn foo<U>(self, x: impl Trait) -> (T, U) { loop {} }
+}
 
-        fn test() {
-            F.foo(S);
-            F::<u32>.foo(S);
-            F::<u32>.foo::<i32>(S);
-            F::<u32>.foo::<i32, u32>(S); // extraneous argument should be ignored
-        }
-        "#,
+fn test() {
+    F.foo(S);
+    F::<u32>.foo(S);
+    F::<u32>.foo::<i32>(S);
+    F::<u32>.foo::<i32, u32>(S); // extraneous argument should be ignored
+}"#,
         expect![[r#"
             87..91 'self': F<T>
             93..94 'x': impl Trait
@@ -1115,15 +1102,14 @@ fn argument_impl_trait_type_args_2() {
 fn argument_impl_trait_to_fn_pointer() {
     check_infer_with_mismatches(
         r#"
-        trait Trait {}
-        fn foo(x: impl Trait) { loop {} }
-        struct S;
-        impl Trait for S {}
+trait Trait {}
+fn foo(x: impl Trait) { loop {} }
+struct S;
+impl Trait for S {}
 
-        fn test() {
-            let f: fn(S) -> () = foo;
-        }
-        "#,
+fn test() {
+    let f: fn(S) -> () = foo;
+}"#,
         expect![[r#"
             22..23 'x': impl Trait
             37..48 '{ loop {} }': ()
@@ -1140,24 +1126,23 @@ fn argument_impl_trait_to_fn_pointer() {
 fn impl_trait() {
     check_infer(
         r#"
-        trait Trait<T> {
-            fn foo(&self) -> T;
-            fn foo2(&self) -> i64;
-        }
-        fn bar() -> impl Trait<u64> {}
+trait Trait<T> {
+    fn foo(&self) -> T;
+    fn foo2(&self) -> i64;
+}
+fn bar() -> impl Trait<u64> {}
 
-        fn test(x: impl Trait<u64>, y: &impl Trait<u64>) {
-            x;
-            y;
-            let z = bar();
-            x.foo();
-            y.foo();
-            z.foo();
-            x.foo2();
-            y.foo2();
-            z.foo2();
-        }
-        "#,
+fn test(x: impl Trait<u64>, y: &impl Trait<u64>) {
+    x;
+    y;
+    let z = bar();
+    x.foo();
+    y.foo();
+    z.foo();
+    x.foo2();
+    y.foo2();
+    z.foo2();
+}"#,
         expect![[r#"
             29..33 'self': &Self
             54..58 'self': &Self
@@ -1191,16 +1176,15 @@ fn simple_return_pos_impl_trait() {
     cov_mark::check!(lower_rpit);
     check_infer(
         r#"
-        trait Trait<T> {
-            fn foo(&self) -> T;
-        }
-        fn bar() -> impl Trait<u64> { loop {} }
+trait Trait<T> {
+    fn foo(&self) -> T;
+}
+fn bar() -> impl Trait<u64> { loop {} }
 
-        fn test() {
-            let a = bar();
-            a.foo();
-        }
-        "#,
+fn test() {
+    let a = bar();
+    a.foo();
+}"#,
         expect![[r#"
             29..33 'self': &Self
             71..82 '{ loop {} }': !
@@ -1220,25 +1204,24 @@ fn simple_return_pos_impl_trait() {
 fn more_return_pos_impl_trait() {
     check_infer(
         r#"
-        trait Iterator {
-            type Item;
-            fn next(&mut self) -> Self::Item;
-        }
-        trait Trait<T> {
-            fn foo(&self) -> T;
-        }
-        fn bar() -> (impl Iterator<Item = impl Trait<u32>>, impl Trait<u64>) { loop {} }
-        fn baz<T>(t: T) -> (impl Iterator<Item = impl Trait<T>>, impl Trait<T>) { loop {} }
-
-        fn test() {
-            let (a, b) = bar();
-            a.next().foo();
-            b.foo();
-            let (c, d) = baz(1u128);
-            c.next().foo();
-            d.foo();
-        }
-        "#,
+trait Iterator {
+    type Item;
+    fn next(&mut self) -> Self::Item;
+}
+trait Trait<T> {
+    fn foo(&self) -> T;
+}
+fn bar() -> (impl Iterator<Item = impl Trait<u32>>, impl Trait<u64>) { loop {} }
+fn baz<T>(t: T) -> (impl Iterator<Item = impl Trait<T>>, impl Trait<T>) { loop {} }
+
+fn test() {
+    let (a, b) = bar();
+    a.next().foo();
+    b.foo();
+    let (c, d) = baz(1u128);
+    c.next().foo();
+    d.foo();
+}"#,
         expect![[r#"
             49..53 'self': &mut Self
             101..105 'self': &Self
@@ -1279,24 +1262,23 @@ fn more_return_pos_impl_trait() {
 fn dyn_trait() {
     check_infer(
         r#"
-        trait Trait<T> {
-            fn foo(&self) -> T;
-            fn foo2(&self) -> i64;
-        }
-        fn bar() -> dyn Trait<u64> {}
+trait Trait<T> {
+    fn foo(&self) -> T;
+    fn foo2(&self) -> i64;
+}
+fn bar() -> dyn Trait<u64> {}
 
-        fn test(x: dyn Trait<u64>, y: &dyn Trait<u64>) {
-            x;
-            y;
-            let z = bar();
-            x.foo();
-            y.foo();
-            z.foo();
-            x.foo2();
-            y.foo2();
-            z.foo2();
-        }
-        "#,
+fn test(x: dyn Trait<u64>, y: &dyn Trait<u64>) {
+    x;
+    y;
+    let z = bar();
+    x.foo();
+    y.foo();
+    z.foo();
+    x.foo2();
+    y.foo2();
+    z.foo2();
+}"#,
         expect![[r#"
             29..33 'self': &Self
             54..58 'self': &Self
@@ -1329,22 +1311,21 @@ fn dyn_trait() {
 fn dyn_trait_in_impl() {
     check_infer(
         r#"
-        trait Trait<T, U> {
-            fn foo(&self) -> (T, U);
-        }
-        struct S<T, U> {}
-        impl<T, U> S<T, U> {
-            fn bar(&self) -> &dyn Trait<T, U> { loop {} }
-        }
-        trait Trait2<T, U> {
-            fn baz(&self) -> (T, U);
-        }
-        impl<T, U> Trait2<T, U> for dyn Trait<T, U> { }
+trait Trait<T, U> {
+    fn foo(&self) -> (T, U);
+}
+struct S<T, U> {}
+impl<T, U> S<T, U> {
+    fn bar(&self) -> &dyn Trait<T, U> { loop {} }
+}
+trait Trait2<T, U> {
+    fn baz(&self) -> (T, U);
+}
+impl<T, U> Trait2<T, U> for dyn Trait<T, U> { }
 
-        fn test(s: S<u32, i32>) {
-            s.bar().baz();
-        }
-        "#,
+fn test(s: S<u32, i32>) {
+    s.bar().baz();
+}"#,
         expect![[r#"
             32..36 'self': &Self
             102..106 'self': &S<T, U>
@@ -1365,20 +1346,19 @@ fn dyn_trait_in_impl() {
 fn dyn_trait_bare() {
     check_infer(
         r#"
-        trait Trait {
-            fn foo(&self) -> u64;
-        }
-        fn bar() -> Trait {}
+trait Trait {
+    fn foo(&self) -> u64;
+}
+fn bar() -> Trait {}
 
-        fn test(x: Trait, y: &Trait) -> u64 {
-            x;
-            y;
-            let z = bar();
-            x.foo();
-            y.foo();
-            z.foo();
-        }
-        "#,
+fn test(x: Trait, y: &Trait) -> u64 {
+    x;
+    y;
+    let z = bar();
+    x.foo();
+    y.foo();
+    z.foo();
+}"#,
         expect![[r#"
             26..30 'self': &Self
             60..62 '{}': ()
@@ -1404,17 +1384,24 @@ fn dyn_trait_bare() {
 fn weird_bounds() {
     check_infer(
         r#"
-        trait Trait {}
-        fn test(a: impl Trait + 'lifetime, b: impl 'lifetime, c: impl (Trait), d: impl ('lifetime), e: impl ?Sized, f: impl Trait + ?Sized) {}
-        "#,
+trait Trait {}
+fn test(
+    a: impl Trait + 'lifetime,
+    b: impl 'lifetime,
+    c: impl (Trait),
+    d: impl ('lifetime),
+    e: impl ?Sized,
+    f: impl Trait + ?Sized
+) {}
+"#,
         expect![[r#"
-            23..24 'a': impl Trait
-            50..51 'b': impl
-            69..70 'c': impl Trait
-            86..87 'd': impl
-            107..108 'e': impl
-            123..124 'f': impl Trait
-            147..149 '{}': ()
+            28..29 'a': impl Trait
+            59..60 'b': impl
+            82..83 'c': impl Trait
+            103..104 'd': impl
+            128..129 'e': impl
+            148..149 'f': impl Trait
+            173..175 '{}': ()
         "#]],
     );
 }
@@ -1439,27 +1426,26 @@ fn test(x: (impl Trait + UnknownTrait)) {
 fn assoc_type_bindings() {
     check_infer(
         r#"
-        trait Trait {
-            type Type;
-        }
+trait Trait {
+    type Type;
+}
 
-        fn get<T: Trait>(t: T) -> <T as Trait>::Type {}
-        fn get2<U, T: Trait<Type = U>>(t: T) -> U {}
-        fn set<T: Trait<Type = u64>>(t: T) -> T {t}
-
-        struct S<T>;
-        impl<T> Trait for S<T> { type Type = T; }
-
-        fn test<T: Trait<Type = u32>>(x: T, y: impl Trait<Type = i64>) {
-            get(x);
-            get2(x);
-            get(y);
-            get2(y);
-            get(set(S));
-            get2(set(S));
-            get2(S::<str>);
-        }
-        "#,
+fn get<T: Trait>(t: T) -> <T as Trait>::Type {}
+fn get2<U, T: Trait<Type = U>>(t: T) -> U {}
+fn set<T: Trait<Type = u64>>(t: T) -> T {t}
+
+struct S<T>;
+impl<T> Trait for S<T> { type Type = T; }
+
+fn test<T: Trait<Type = u32>>(x: T, y: impl Trait<Type = i64>) {
+    get(x);
+    get2(x);
+    get(y);
+    get2(y);
+    get(set(S));
+    get2(set(S));
+    get2(S::<str>);
+}"#,
         expect![[r#"
             49..50 't': T
             77..79 '{}': ()
@@ -1546,18 +1532,17 @@ mod iter {
 fn projection_eq_within_chalk() {
     check_infer(
         r#"
-        trait Trait1 {
-            type Type;
-        }
-        trait Trait2<T> {
-            fn foo(self) -> T;
-        }
-        impl<T, U> Trait2<T> for U where U: Trait1<Type = T> {}
+trait Trait1 {
+    type Type;
+}
+trait Trait2<T> {
+    fn foo(self) -> T;
+}
+impl<T, U> Trait2<T> for U where U: Trait1<Type = T> {}
 
-        fn test<T: Trait1<Type = u32>>(x: T) {
-            x.foo();
-        }
-        "#,
+fn test<T: Trait1<Type = u32>>(x: T) {
+    x.foo();
+}"#,
         expect![[r#"
             61..65 'self': Self
             163..164 'x': T
@@ -1589,19 +1574,18 @@ fn test<T: foo::Trait>(x: T) {
 fn super_trait_method_resolution() {
     check_infer(
         r#"
-        mod foo {
-            trait SuperTrait {
-                fn foo(&self) -> u32 {}
-            }
-        }
-        trait Trait1: foo::SuperTrait {}
-        trait Trait2 where Self: foo::SuperTrait {}
+mod foo {
+    trait SuperTrait {
+        fn foo(&self) -> u32 {}
+    }
+}
+trait Trait1: foo::SuperTrait {}
+trait Trait2 where Self: foo::SuperTrait {}
 
-        fn test<T: Trait1, U: Trait2>(x: T, y: U) {
-            x.foo();
-            y.foo();
-        }
-        "#,
+fn test<T: Trait1, U: Trait2>(x: T, y: U) {
+    x.foo();
+    y.foo();
+}"#,
         expect![[r#"
             49..53 'self': &Self
             62..64 '{}': ()
@@ -1620,17 +1604,16 @@ fn super_trait_method_resolution() {
 fn super_trait_impl_trait_method_resolution() {
     check_infer(
         r#"
-        mod foo {
-            trait SuperTrait {
-                fn foo(&self) -> u32 {}
-            }
-        }
-        trait Trait1: foo::SuperTrait {}
+mod foo {
+    trait SuperTrait {
+        fn foo(&self) -> u32 {}
+    }
+}
+trait Trait1: foo::SuperTrait {}
 
-        fn test(x: &impl Trait1) {
-            x.foo();
-        }
-        "#,
+fn test(x: &impl Trait1) {
+    x.foo();
+}"#,
         expect![[r#"
             49..53 'self': &Self
             62..64 '{}': ()
@@ -1667,20 +1650,19 @@ fn super_trait_cycle() {
 fn super_trait_assoc_type_bounds() {
     check_infer(
         r#"
-        trait SuperTrait { type Type; }
-        trait Trait where Self: SuperTrait {}
+trait SuperTrait { type Type; }
+trait Trait where Self: SuperTrait {}
 
-        fn get2<U, T: Trait<Type = U>>(t: T) -> U {}
-        fn set<T: Trait<Type = u64>>(t: T) -> T {t}
+fn get2<U, T: Trait<Type = U>>(t: T) -> U {}
+fn set<T: Trait<Type = u64>>(t: T) -> T {t}
 
-        struct S<T>;
-        impl<T> SuperTrait for S<T> { type Type = T; }
-        impl<T> Trait for S<T> {}
+struct S<T>;
+impl<T> SuperTrait for S<T> { type Type = T; }
+impl<T> Trait for S<T> {}
 
-        fn test() {
-            get2(set(S));
-        }
-        "#,
+fn test() {
+    get2(set(S));
+}"#,
         expect![[r#"
             102..103 't': T
             113..115 '{}': ()
@@ -1701,16 +1683,15 @@ fn super_trait_assoc_type_bounds() {
 fn fn_trait() {
     check_infer_with_mismatches(
         r#"
-        trait FnOnce<Args> {
-            type Output;
+trait FnOnce<Args> {
+    type Output;
 
-            fn call_once(self, args: Args) -> <Self as FnOnce<Args>>::Output;
-        }
+    fn call_once(self, args: Args) -> <Self as FnOnce<Args>>::Output;
+}
 
-        fn test<F: FnOnce(u32, u64) -> u128>(f: F) {
-            f.call_once((1, 2));
-        }
-        "#,
+fn test<F: FnOnce(u32, u64) -> u128>(f: F) {
+    f.call_once((1, 2));
+}"#,
         expect![[r#"
             56..60 'self': Self
             62..66 'args': Args
@@ -1729,37 +1710,36 @@ fn fn_trait() {
 fn fn_ptr_and_item() {
     check_infer_with_mismatches(
         r#"
-        #[lang="fn_once"]
-        trait FnOnce<Args> {
-            type Output;
+#[lang="fn_once"]
+trait FnOnce<Args> {
+    type Output;
 
-            fn call_once(self, args: Args) -> Self::Output;
-        }
+    fn call_once(self, args: Args) -> Self::Output;
+}
 
-        trait Foo<T> {
-            fn foo(&self) -> T;
-        }
+trait Foo<T> {
+    fn foo(&self) -> T;
+}
 
-        struct Bar<T>(T);
+struct Bar<T>(T);
 
-        impl<A1, R, F: FnOnce(A1) -> R> Foo<(A1, R)> for Bar<F> {
-            fn foo(&self) -> (A1, R) { loop {} }
-        }
+impl<A1, R, F: FnOnce(A1) -> R> Foo<(A1, R)> for Bar<F> {
+    fn foo(&self) -> (A1, R) { loop {} }
+}
 
-        enum Opt<T> { None, Some(T) }
-        impl<T> Opt<T> {
-            fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Opt<U> { loop {} }
-        }
+enum Opt<T> { None, Some(T) }
+impl<T> Opt<T> {
+    fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Opt<U> { loop {} }
+}
 
-        fn test() {
-            let bar: Bar<fn(u8) -> u32>;
-            bar.foo();
+fn test() {
+    let bar: Bar<fn(u8) -> u32>;
+    bar.foo();
 
-            let opt: Opt<u8>;
-            let f: fn(u8) -> u32;
-            opt.map(f);
-        }
-        "#,
+    let opt: Opt<u8>;
+    let f: fn(u8) -> u32;
+    opt.map(f);
+}"#,
         expect![[r#"
             74..78 'self': Self
             80..84 'args': Args
@@ -1790,46 +1770,45 @@ fn fn_ptr_and_item() {
 fn fn_trait_deref_with_ty_default() {
     check_infer(
         r#"
-        #[lang = "deref"]
-        trait Deref {
-            type Target;
+#[lang = "deref"]
+trait Deref {
+    type Target;
 
-            fn deref(&self) -> &Self::Target;
-        }
+    fn deref(&self) -> &Self::Target;
+}
 
-        #[lang="fn_once"]
-        trait FnOnce<Args> {
-            type Output;
+#[lang="fn_once"]
+trait FnOnce<Args> {
+    type Output;
 
-            fn call_once(self, args: Args) -> Self::Output;
-        }
+    fn call_once(self, args: Args) -> Self::Output;
+}
 
-        struct Foo;
+struct Foo;
 
-        impl Foo {
-            fn foo(&self) -> usize {}
-        }
+impl Foo {
+    fn foo(&self) -> usize {}
+}
 
-        struct Lazy<T, F = fn() -> T>(F);
+struct Lazy<T, F = fn() -> T>(F);
 
-        impl<T, F> Lazy<T, F> {
-            pub fn new(f: F) -> Lazy<T, F> {}
-        }
+impl<T, F> Lazy<T, F> {
+    pub fn new(f: F) -> Lazy<T, F> {}
+}
 
-        impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
-            type Target = T;
-        }
+impl<T, F: FnOnce() -> T> Deref for Lazy<T, F> {
+    type Target = T;
+}
 
-        fn test() {
-            let lazy1: Lazy<Foo, _> = Lazy::new(|| Foo);
-            let r1 = lazy1.foo();
+fn test() {
+    let lazy1: Lazy<Foo, _> = Lazy::new(|| Foo);
+    let r1 = lazy1.foo();
 
-            fn make_foo_fn() -> Foo {}
-            let make_foo_fn_ptr: fn() -> Foo = make_foo_fn;
-            let lazy2: Lazy<Foo, _> = Lazy::new(make_foo_fn_ptr);
-            let r2 = lazy2.foo();
-        }
-        "#,
+    fn make_foo_fn() -> Foo {}
+    let make_foo_fn_ptr: fn() -> Foo = make_foo_fn;
+    let lazy2: Lazy<Foo, _> = Lazy::new(make_foo_fn_ptr);
+    let r2 = lazy2.foo();
+}"#,
         expect![[r#"
             64..68 'self': &Self
             165..169 'self': Self
@@ -1865,23 +1844,22 @@ fn fn_trait_deref_with_ty_default() {
 fn closure_1() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "fn_once"]
-        trait FnOnce<Args> {
-            type Output;
-        }
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
 
-        enum Option<T> { Some(T), None }
-        impl<T> Option<T> {
-            fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Option<U> { loop {} }
-        }
+enum Option<T> { Some(T), None }
+impl<T> Option<T> {
+    fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Option<U> { loop {} }
+}
 
-        fn test() {
-            let x = Option::Some(1u32);
-            x.map(|v| v + 1);
-            x.map(|_v| 1u64);
-            let y: Option<i64> = x.map(|_v| 1);
-        }
-        "#,
+fn test() {
+    let x = Option::Some(1u32);
+    x.map(|v| v + 1);
+    x.map(|_v| 1u64);
+    let y: Option<i64> = x.map(|_v| 1);
+}"#,
         expect![[r#"
             147..151 'self': Option<T>
             153..154 'f': F
@@ -1919,38 +1897,63 @@ fn closure_1() {
 fn closure_2() {
     check_infer_with_mismatches(
         r#"
-        trait FnOnce<Args> {
-            type Output;
-        }
+#[lang = "add"]
+pub trait Add<Rhs = Self> {
+    type Output;
+    fn add(self, rhs: Rhs) -> Self::Output;
+}
 
-        fn test<F: FnOnce(u32) -> u64>(f: F) {
-            f(1);
-            let g = |v| v + 1;
-            g(1u64);
-            let h = |v| 1u128 + v;
-        }
-        "#,
+trait FnOnce<Args> {
+    type Output;
+}
+
+impl Add for u64 {
+    type Output = Self;
+    fn add(self, rhs: u64) -> Self::Output {0}
+}
+
+impl Add for u128 {
+    type Output = Self;
+    fn add(self, rhs: u128) -> Self::Output {0}
+}
+
+fn test<F: FnOnce(u32) -> u64>(f: F) {
+    f(1);
+    let g = |v| v + 1;
+    g(1u64);
+    let h = |v| 1u128 + v;
+}"#,
         expect![[r#"
-            72..73 'f': F
-            78..154 '{     ...+ v; }': ()
-            84..85 'f': F
-            84..88 'f(1)': {unknown}
-            86..87 '1': i32
-            98..99 'g': |u64| -> i32
-            102..111 '|v| v + 1': |u64| -> i32
-            103..104 'v': u64
-            106..107 'v': u64
-            106..111 'v + 1': i32
-            110..111 '1': i32
-            117..118 'g': |u64| -> i32
-            117..124 'g(1u64)': i32
-            119..123 '1u64': u64
-            134..135 'h': |u128| -> u128
-            138..151 '|v| 1u128 + v': |u128| -> u128
-            139..140 'v': u128
-            142..147 '1u128': u128
-            142..151 '1u128 + v': u128
-            150..151 'v': u128
+            72..76 'self': Self
+            78..81 'rhs': Rhs
+            203..207 'self': u64
+            209..212 'rhs': u64
+            235..238 '{0}': u64
+            236..237 '0': u64
+            297..301 'self': u128
+            303..306 'rhs': u128
+            330..333 '{0}': u128
+            331..332 '0': u128
+            368..369 'f': F
+            374..450 '{     ...+ v; }': ()
+            380..381 'f': F
+            380..384 'f(1)': {unknown}
+            382..383 '1': i32
+            394..395 'g': |u64| -> u64
+            398..407 '|v| v + 1': |u64| -> u64
+            399..400 'v': u64
+            402..403 'v': u64
+            402..407 'v + 1': u64
+            406..407 '1': u64
+            413..414 'g': |u64| -> u64
+            413..420 'g(1u64)': u64
+            415..419 '1u64': u64
+            430..431 'h': |u128| -> u128
+            434..447 '|v| 1u128 + v': |u128| -> u128
+            435..436 'v': u128
+            438..443 '1u128': u128
+            438..447 '1u128 + v': u128
+            446..447 'v': u128
         "#]],
     );
 }
@@ -1959,29 +1962,28 @@ fn closure_2() {
 fn closure_as_argument_inference_order() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "fn_once"]
-        trait FnOnce<Args> {
-            type Output;
-        }
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
 
-        fn foo1<T, U, F: FnOnce(T) -> U>(x: T, f: F) -> U { loop {} }
-        fn foo2<T, U, F: FnOnce(T) -> U>(f: F, x: T) -> U { loop {} }
+fn foo1<T, U, F: FnOnce(T) -> U>(x: T, f: F) -> U { loop {} }
+fn foo2<T, U, F: FnOnce(T) -> U>(f: F, x: T) -> U { loop {} }
 
-        struct S;
-        impl S {
-            fn method(self) -> u64;
+struct S;
+impl S {
+    fn method(self) -> u64;
 
-            fn foo1<T, U, F: FnOnce(T) -> U>(self, x: T, f: F) -> U { loop {} }
-            fn foo2<T, U, F: FnOnce(T) -> U>(self, f: F, x: T) -> U { loop {} }
-        }
+    fn foo1<T, U, F: FnOnce(T) -> U>(self, x: T, f: F) -> U { loop {} }
+    fn foo2<T, U, F: FnOnce(T) -> U>(self, f: F, x: T) -> U { loop {} }
+}
 
-        fn test() {
-            let x1 = foo1(S, |s| s.method());
-            let x2 = foo2(|s| s.method(), S);
-            let x3 = S.foo1(S, |s| s.method());
-            let x4 = S.foo2(|s| s.method(), S);
-        }
-        "#,
+fn test() {
+    let x1 = foo1(S, |s| s.method());
+    let x2 = foo2(|s| s.method(), S);
+    let x3 = S.foo1(S, |s| s.method());
+    let x4 = S.foo2(|s| s.method(), S);
+}"#,
         expect![[r#"
             94..95 'x': T
             100..101 'f': F
@@ -2110,27 +2112,26 @@ fn test<T, U>() where T::Item: Trait2, T: Trait<U::Item>, U: Trait<()> {
 fn unselected_projection_on_impl_self() {
     check_infer(
         r#"
-        //- /main.rs
-        trait Trait {
-            type Item;
+//- /main.rs
+trait Trait {
+    type Item;
 
-            fn f(&self, x: Self::Item);
-        }
+    fn f(&self, x: Self::Item);
+}
 
-        struct S;
+struct S;
 
-        impl Trait for S {
-            type Item = u32;
-            fn f(&self, x: Self::Item) { let y = x; }
-        }
+impl Trait for S {
+    type Item = u32;
+    fn f(&self, x: Self::Item) { let y = x; }
+}
 
-        struct S2;
+struct S2;
 
-        impl Trait for S2 {
-            type Item = i32;
-            fn f(&self, x: <Self>::Item) { let y = x; }
-        }
-        "#,
+impl Trait for S2 {
+    type Item = i32;
+    fn f(&self, x: <Self>::Item) { let y = x; }
+}"#,
         expect![[r#"
             40..44 'self': &Self
             46..47 'x': Trait::Item<Self>
@@ -2366,58 +2367,57 @@ fn test<I: Iterator<Item: Iterator<Item = u32>>>() {
 fn proc_macro_server_types() {
     check_infer(
         r#"
-        macro_rules! with_api {
-            ($S:ident, $self:ident, $m:ident) => {
-                $m! {
-                    TokenStream {
-                        fn new() -> $S::TokenStream;
-                    },
-                    Group {
-                    },
-                }
-            };
+macro_rules! with_api {
+    ($S:ident, $self:ident, $m:ident) => {
+        $m! {
+            TokenStream {
+                fn new() -> $S::TokenStream;
+            },
+            Group {
+            },
         }
-        macro_rules! associated_item {
-            (type TokenStream) =>
-                (type TokenStream: 'static;);
-            (type Group) =>
-                (type Group: 'static;);
-            ($($item:tt)*) => ($($item)*;)
-        }
-        macro_rules! declare_server_traits {
-            ($($name:ident {
-                $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
-            }),* $(,)?) => {
-                pub trait Types {
-                    $(associated_item!(type $name);)*
-                }
-
-                $(pub trait $name: Types {
-                    $(associated_item!(fn $method($($arg: $arg_ty),*) $(-> $ret_ty)?);)*
-                })*
-
-                pub trait Server: Types $(+ $name)* {}
-                impl<S: Types $(+ $name)*> Server for S {}
-            }
+    };
+}
+macro_rules! associated_item {
+    (type TokenStream) =>
+        (type TokenStream: 'static;);
+    (type Group) =>
+        (type Group: 'static;);
+    ($($item:tt)*) => ($($item)*;)
+}
+macro_rules! declare_server_traits {
+    ($($name:ident {
+        $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
+    }),* $(,)?) => {
+        pub trait Types {
+            $(associated_item!(type $name);)*
         }
 
-        with_api!(Self, self_, declare_server_traits);
-        struct G {}
-        struct T {}
-        struct Rustc;
-        impl Types for Rustc {
-            type TokenStream = T;
-            type Group = G;
-        }
+        $(pub trait $name: Types {
+            $(associated_item!(fn $method($($arg: $arg_ty),*) $(-> $ret_ty)?);)*
+        })*
 
-        fn make<T>() -> T { loop {} }
-        impl TokenStream for Rustc {
-            fn new() -> Self::TokenStream {
-                let group: Self::Group = make();
-                make()
-            }
-        }
-        "#,
+        pub trait Server: Types $(+ $name)* {}
+        impl<S: Types $(+ $name)*> Server for S {}
+    }
+}
+
+with_api!(Self, self_, declare_server_traits);
+struct G {}
+struct T {}
+struct Rustc;
+impl Types for Rustc {
+    type TokenStream = T;
+    type Group = G;
+}
+
+fn make<T>() -> T { loop {} }
+impl TokenStream for Rustc {
+    fn new() -> Self::TokenStream {
+        let group: Self::Group = make();
+        make()
+    }
+}"#,
         expect![[r#"
             1061..1072 '{ loop {} }': T
             1063..1070 'loop {}': !
@@ -2436,23 +2436,22 @@ fn proc_macro_server_types() {
 fn unify_impl_trait() {
     check_infer_with_mismatches(
         r#"
-        trait Trait<T> {}
+trait Trait<T> {}
 
-        fn foo(x: impl Trait<u32>) { loop {} }
-        fn bar<T>(x: impl Trait<T>) -> T { loop {} }
+fn foo(x: impl Trait<u32>) { loop {} }
+fn bar<T>(x: impl Trait<T>) -> T { loop {} }
 
-        struct S<T>(T);
-        impl<T> Trait<T> for S<T> {}
+struct S<T>(T);
+impl<T> Trait<T> for S<T> {}
 
-        fn default<T>() -> T { loop {} }
+fn default<T>() -> T { loop {} }
 
-        fn test() -> impl Trait<i32> {
-            let s1 = S(default());
-            foo(s1);
-            let x: i32 = bar(S(default()));
-            S(default())
-        }
-        "#,
+fn test() -> impl Trait<i32> {
+    let s1 = S(default());
+    foo(s1);
+    let x: i32 = bar(S(default()));
+    S(default())
+}"#,
         expect![[r#"
             26..27 'x': impl Trait<u32>
             46..57 '{ loop {} }': ()
@@ -2493,30 +2492,29 @@ fn unify_impl_trait() {
 fn assoc_types_from_bounds() {
     check_infer(
         r#"
-        //- /main.rs
-        #[lang = "fn_once"]
-        trait FnOnce<Args> {
-            type Output;
-        }
+//- /main.rs
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
 
-        trait T {
-            type O;
-        }
+trait T {
+    type O;
+}
 
-        impl T for () {
-            type O = ();
-        }
+impl T for () {
+    type O = ();
+}
 
-        fn f<X, F>(_v: F)
-        where
-            X: T,
-            F: FnOnce(&X::O),
-        { }
+fn f<X, F>(_v: F)
+where
+    X: T,
+    F: FnOnce(&X::O),
+{ }
 
-        fn main() {
-            f::<(), _>(|z| { z; });
-        }
-        "#,
+fn main() {
+    f::<(), _>(|z| { z; });
+}"#,
         expect![[r#"
             133..135 '_v': F
             178..181 '{ }': ()
@@ -2602,76 +2600,75 @@ fn test() {
 fn iterator_chain() {
     check_infer_with_mismatches(
         r#"
-        //- /main.rs
-        #[lang = "fn_once"]
-        trait FnOnce<Args> {
-            type Output;
-        }
-        #[lang = "fn_mut"]
-        trait FnMut<Args>: FnOnce<Args> { }
+//- /main.rs
+#[lang = "fn_once"]
+trait FnOnce<Args> {
+    type Output;
+}
+#[lang = "fn_mut"]
+trait FnMut<Args>: FnOnce<Args> { }
 
-        enum Option<T> { Some(T), None }
-        use Option::*;
+enum Option<T> { Some(T), None }
+use Option::*;
 
-        pub trait Iterator {
-            type Item;
+pub trait Iterator {
+    type Item;
 
-            fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>
-            where
-                F: FnMut(Self::Item) -> Option<B>,
-            { loop {} }
+    fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>
+    where
+        F: FnMut(Self::Item) -> Option<B>,
+    { loop {} }
 
-            fn for_each<F>(self, f: F)
-            where
-                F: FnMut(Self::Item),
-            { loop {} }
-        }
+    fn for_each<F>(self, f: F)
+    where
+        F: FnMut(Self::Item),
+    { loop {} }
+}
 
-        pub trait IntoIterator {
-            type Item;
-            type IntoIter: Iterator<Item = Self::Item>;
-            fn into_iter(self) -> Self::IntoIter;
-        }
+pub trait IntoIterator {
+    type Item;
+    type IntoIter: Iterator<Item = Self::Item>;
+    fn into_iter(self) -> Self::IntoIter;
+}
 
-        pub struct FilterMap<I, F> { }
-        impl<B, I: Iterator, F> Iterator for FilterMap<I, F>
-        where
-            F: FnMut(I::Item) -> Option<B>,
-        {
-            type Item = B;
-        }
+pub struct FilterMap<I, F> { }
+impl<B, I: Iterator, F> Iterator for FilterMap<I, F>
+where
+    F: FnMut(I::Item) -> Option<B>,
+{
+    type Item = B;
+}
 
-        #[stable(feature = "rust1", since = "1.0.0")]
-        impl<I: Iterator> IntoIterator for I {
-            type Item = I::Item;
-            type IntoIter = I;
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator> IntoIterator for I {
+    type Item = I::Item;
+    type IntoIter = I;
 
-            fn into_iter(self) -> I {
-                self
-            }
-        }
+    fn into_iter(self) -> I {
+        self
+    }
+}
 
-        struct Vec<T> {}
-        impl<T> Vec<T> {
-            fn new() -> Self { loop {} }
-        }
+struct Vec<T> {}
+impl<T> Vec<T> {
+    fn new() -> Self { loop {} }
+}
 
-        impl<T> IntoIterator for Vec<T> {
-            type Item = T;
-            type IntoIter = IntoIter<T>;
-        }
+impl<T> IntoIterator for Vec<T> {
+    type Item = T;
+    type IntoIter = IntoIter<T>;
+}
 
-        pub struct IntoIter<T> { }
-        impl<T> Iterator for IntoIter<T> {
-            type Item = T;
-        }
+pub struct IntoIter<T> { }
+impl<T> Iterator for IntoIter<T> {
+    type Item = T;
+}
 
-        fn main() {
-            Vec::<i32>::new().into_iter()
-            .filter_map(|x| if x > 0 { Some(x as u32) } else { None })
-            .for_each(|y| { y; });
-        }
-        "#,
+fn main() {
+    Vec::<i32>::new().into_iter()
+    .filter_map(|x| if x > 0 { Some(x as u32) } else { None })
+    .for_each(|y| { y; });
+}"#,
         expect![[r#"
             226..230 'self': Self
             232..233 'f': F
@@ -2753,14 +2750,13 @@ fn main() {
 fn trait_object_no_coercion() {
     check_infer_with_mismatches(
         r#"
-        trait Foo {}
+trait Foo {}
 
-        fn foo(x: &dyn Foo) {}
+fn foo(x: &dyn Foo) {}
 
-        fn test(x: &dyn Foo) {
-            foo(x);
-        }
-        "#,
+fn test(x: &dyn Foo) {
+    foo(x);
+}"#,
         expect![[r#"
             21..22 'x': &dyn Foo
             34..36 '{}': ()
@@ -2777,23 +2773,22 @@ fn trait_object_no_coercion() {
 fn builtin_copy() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "copy"]
-        trait Copy {}
+#[lang = "copy"]
+trait Copy {}
 
-        struct IsCopy;
-        impl Copy for IsCopy {}
-        struct NotCopy;
+struct IsCopy;
+impl Copy for IsCopy {}
+struct NotCopy;
 
-        trait Test { fn test(&self) -> bool; }
-        impl<T: Copy> Test for T {}
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
 
-        fn test() {
-            IsCopy.test();
-            NotCopy.test();
-            (IsCopy, IsCopy).test();
-            (IsCopy, NotCopy).test();
-        }
-        "#,
+fn test() {
+    IsCopy.test();
+    NotCopy.test();
+    (IsCopy, IsCopy).test();
+    (IsCopy, NotCopy).test();
+}"#,
         expect![[r#"
             110..114 'self': &Self
             166..267 '{     ...t(); }': ()
@@ -2817,24 +2812,23 @@ fn builtin_copy() {
 fn builtin_fn_def_copy() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "copy"]
-        trait Copy {}
+#[lang = "copy"]
+trait Copy {}
 
-        fn foo() {}
-        fn bar<T: Copy>(T) -> T {}
-        struct Struct(usize);
-        enum Enum { Variant(usize) }
+fn foo() {}
+fn bar<T: Copy>(T) -> T {}
+struct Struct(usize);
+enum Enum { Variant(usize) }
 
-        trait Test { fn test(&self) -> bool; }
-        impl<T: Copy> Test for T {}
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
 
-        fn test() {
-            foo.test();
-            bar.test();
-            Struct.test();
-            Enum::Variant.test();
-        }
-        "#,
+fn test() {
+    foo.test();
+    bar.test();
+    Struct.test();
+    Enum::Variant.test();
+}"#,
         expect![[r#"
             41..43 '{}': ()
             60..61 'T': {unknown}
@@ -2858,18 +2852,17 @@ fn builtin_fn_def_copy() {
 fn builtin_fn_ptr_copy() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "copy"]
-        trait Copy {}
+#[lang = "copy"]
+trait Copy {}
 
-        trait Test { fn test(&self) -> bool; }
-        impl<T: Copy> Test for T {}
+trait Test { fn test(&self) -> bool; }
+impl<T: Copy> Test for T {}
 
-        fn test(f1: fn(), f2: fn(usize) -> u8, f3: fn(u8, u8) -> &u8) {
-            f1.test();
-            f2.test();
-            f3.test();
-        }
-        "#,
+fn test(f1: fn(), f2: fn(usize) -> u8, f3: fn(u8, u8) -> &u8) {
+    f1.test();
+    f2.test();
+    f3.test();
+}"#,
         expect![[r#"
             54..58 'self': &Self
             108..110 'f1': fn()
@@ -2890,19 +2883,18 @@ fn builtin_fn_ptr_copy() {
 fn builtin_sized() {
     check_infer_with_mismatches(
         r#"
-        #[lang = "sized"]
-        trait Sized {}
+#[lang = "sized"]
+trait Sized {}
 
-        trait Test { fn test(&self) -> bool; }
-        impl<T: Sized> Test for T {}
+trait Test { fn test(&self) -> bool; }
+impl<T: Sized> Test for T {}
 
-        fn test() {
-            1u8.test();
-            (*"foo").test(); // not Sized
-            (1u8, 1u8).test();
-            (1u8, *"foo").test(); // not Sized
-        }
-        "#,
+fn test() {
+    1u8.test();
+    (*"foo").test(); // not Sized
+    (1u8, 1u8).test();
+    (1u8, *"foo").test(); // not Sized
+}"#,
         expect![[r#"
             56..60 'self': &Self
             113..228 '{     ...ized }': ()
@@ -2972,19 +2964,18 @@ impl<A: Step> iter::Iterator for ops::Range<A> {
 fn infer_closure_arg() {
     check_infer(
         r#"
-        //- /lib.rs
+//- /lib.rs
 
-        enum Option<T> {
-            None,
-            Some(T)
-        }
+enum Option<T> {
+    None,
+    Some(T)
+}
 
-        fn foo() {
-            let s = Option::None;
-            let f = |x: Option<i32>| {};
-            (&f)(s)
-        }
-        "#,
+fn foo() {
+    let s = Option::None;
+    let f = |x: Option<i32>| {};
+    (&f)(s)
+}"#,
         expect![[r#"
             52..126 '{     ...)(s) }': ()
             62..63 's': Option<i32>
@@ -3053,46 +3044,45 @@ fn infer_box_fn_arg() {
     // The type mismatch is a bug
     check_infer_with_mismatches(
         r#"
-        //- /lib.rs deps:std
+//- /lib.rs deps:std
 
-        #[lang = "fn_once"]
-        pub trait FnOnce<Args> {
-            type Output;
+#[lang = "fn_once"]
+pub trait FnOnce<Args> {
+    type Output;
 
-            extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-        }
+    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
+}
 
-        #[lang = "deref"]
-        pub trait Deref {
-            type Target: ?Sized;
+#[lang = "deref"]
+pub trait Deref {
+    type Target: ?Sized;
 
-            fn deref(&self) -> &Self::Target;
-        }
+    fn deref(&self) -> &Self::Target;
+}
 
-        #[lang = "owned_box"]
-        pub struct Box<T: ?Sized> {
-            inner: *mut T,
-        }
+#[lang = "owned_box"]
+pub struct Box<T: ?Sized> {
+    inner: *mut T,
+}
 
-        impl<T: ?Sized> Deref for Box<T> {
-            type Target = T;
+impl<T: ?Sized> Deref for Box<T> {
+    type Target = T;
 
-            fn deref(&self) -> &T {
-                &self.inner
-            }
-        }
+    fn deref(&self) -> &T {
+        &self.inner
+    }
+}
 
-        enum Option<T> {
-            None,
-            Some(T)
-        }
+enum Option<T> {
+    None,
+    Some(T)
+}
 
-        fn foo() {
-            let s = Option::None;
-            let f: Box<dyn FnOnce(&Option<i32>)> = box (|ps| {});
-            f(&s);
-        }
-        "#,
+fn foo() {
+    let s = Option::None;
+    let f: Box<dyn FnOnce(&Option<i32>)> = box (|ps| {});
+    f(&s);
+}"#,
         expect![[r#"
             100..104 'self': Self
             106..110 'args': Args
@@ -3258,8 +3248,7 @@ fn f() {
         ().method();
       //^^^^^^^^^^^ u8
     }
-}
-        "#,
+}"#,
         expect![[r#"
             46..50 'self': &Self
             58..63 '{ 0 }': u8
@@ -3313,8 +3302,7 @@ fn f() {
     fn inner() -> S {
         let s = inner();
     }
-}
-        "#,
+}"#,
         expect![[r#"
             17..73 '{     ...   } }': ()
             39..71 '{     ...     }': ()
@@ -3349,8 +3337,7 @@ fn test() {
     let x = A;
     let y = A;
     let r = x.do_op(y);
-}
-        "#,
+}"#,
         expect![[r#"
             63..67 'self': Self
             69..72 'rhs': RHS
@@ -3399,9 +3386,7 @@ impl foo::Bar for F {
 fn foo() {
     use foo::Bar;
     let x = <F as Bar>::boo();
-}
-
-        "#,
+}"#,
         expect![[r#"
             132..163 '{     ...     }': Bar::Output<Self>
             146..153 'loop {}': !
@@ -3413,3 +3398,79 @@ fn foo() {
         "#]],
     );
 }
+
+#[test]
+fn renamed_extern_crate_in_block() {
+    check_types(
+        r#"
+//- /lib.rs crate:lib deps:serde
+use serde::Deserialize;
+
+struct Foo {}
+
+const _ : () = {
+    extern crate serde as _serde;
+    impl _serde::Deserialize for Foo {
+        fn deserialize() -> u8 { 0 }
+    }
+};
+
+fn foo() {
+    Foo::deserialize();
+  //^^^^^^^^^^^^^^^^^^ u8
+}
+
+//- /serde.rs crate:serde
+
+pub trait Deserialize {
+    fn deserialize() -> u8;
+}"#,
+    );
+}
+
+#[test]
+fn bin_op_adt_with_rhs_primitive() {
+    check_infer_with_mismatches(
+        r#"
+#[lang = "add"]
+pub trait Add<Rhs = Self> {
+    type Output;
+    fn add(self, rhs: Rhs) -> Self::Output;
+}
+
+struct Wrapper(u32);
+impl Add<u32> for Wrapper {
+    type Output = Self;
+    fn add(self, rhs: u32) -> Wrapper {
+        Wrapper(rhs)
+    }
+}
+fn main(){
+    let wrapped = Wrapper(10);
+    let num: u32 = 2;
+    let res = wrapped + num;
+
+}"#,
+        expect![[r#"
+            72..76 'self': Self
+            78..81 'rhs': Rhs
+            192..196 'self': Wrapper
+            198..201 'rhs': u32
+            219..247 '{     ...     }': Wrapper
+            229..236 'Wrapper': Wrapper(u32) -> Wrapper
+            229..241 'Wrapper(rhs)': Wrapper
+            237..240 'rhs': u32
+            259..345 '{     ...um;  }': ()
+            269..276 'wrapped': Wrapper
+            279..286 'Wrapper': Wrapper(u32) -> Wrapper
+            279..290 'Wrapper(10)': Wrapper
+            287..289 '10': u32
+            300..303 'num': u32
+            311..312 '2': u32
+            322..325 'res': Wrapper
+            328..335 'wrapped': Wrapper
+            328..341 'wrapped + num': Wrapper
+            338..341 'num': u32
+        "#]],
+    )
+}
diff --git a/crates/hir_ty/src/traits/chalk/tls.rs b/crates/hir_ty/src/tls.rs
index 8892a63a9..87c671a42 100644
--- a/crates/hir_ty/src/traits/chalk/tls.rs
+++ b/crates/hir_ty/src/tls.rs
@@ -4,8 +4,10 @@ use std::fmt;
 use chalk_ir::{AliasTy, GenericArg, Goal, Goals, Lifetime, ProgramClauseImplication};
 use itertools::Itertools;
 
-use super::{from_chalk, Interner};
-use crate::{db::HirDatabase, from_assoc_type_id, CallableDefId};
+use crate::{
+    chalk_db, db::HirDatabase, from_assoc_type_id, from_chalk_trait_id, mapping::from_chalk,
+    CallableDefId, Interner,
+};
 use hir_def::{AdtId, AssocContainerId, Lookup, TypeAliasId};
 
 pub(crate) use unsafe_tls::{set_current_program, with_current_program};
@@ -15,7 +17,7 @@ pub(crate) struct DebugContext<'a>(&'a dyn HirDatabase);
 impl DebugContext<'_> {
     pub(crate) fn debug_struct_id(
         &self,
-        id: super::AdtId,
+        id: chalk_db::AdtId,
         f: &mut fmt::Formatter<'_>,
     ) -> Result<(), fmt::Error> {
         let name = match id.0 {
@@ -28,17 +30,17 @@ impl DebugContext<'_> {
 
     pub(crate) fn debug_trait_id(
         &self,
-        id: super::TraitId,
+        id: chalk_db::TraitId,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Result<(), fmt::Error> {
-        let trait_: hir_def::TraitId = from_chalk(self.0, id);
+        let trait_: hir_def::TraitId = from_chalk_trait_id(id);
         let trait_data = self.0.trait_data(trait_);
         write!(fmt, "{}", trait_data.name)
     }
 
     pub(crate) fn debug_assoc_type_id(
         &self,
-        id: super::AssocTypeId,
+        id: chalk_db::AssocTypeId,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Result<(), fmt::Error> {
         let type_alias: TypeAliasId = from_assoc_type_id(id);
diff --git a/crates/hir_ty/src/traits.rs b/crates/hir_ty/src/traits.rs
index 1cda72d22..9936d0803 100644
--- a/crates/hir_ty/src/traits.rs
+++ b/crates/hir_ty/src/traits.rs
@@ -1,28 +1,26 @@
 //! Trait solving using Chalk.
+
 use std::env::var;
 
-use base_db::CrateId;
 use chalk_ir::cast::Cast;
 use chalk_solve::{logging_db::LoggingRustIrDatabase, Solver};
+
+use base_db::CrateId;
 use hir_def::{lang_item::LangItemTarget, TraitId};
 use stdx::panic_context;
 
 use crate::{
     db::HirDatabase, AliasEq, AliasTy, Canonical, DomainGoal, Guidance, HirDisplay, InEnvironment,
-    Solution, TraitRefExt, Ty, TyKind, WhereClause,
+    Interner, Solution, TraitRefExt, Ty, TyKind, WhereClause,
 };
 
-use self::chalk::Interner;
-
-pub(crate) mod chalk;
-
 /// This controls how much 'time' we give the Chalk solver before giving up.
 const CHALK_SOLVER_FUEL: i32 = 100;
 
 #[derive(Debug, Copy, Clone)]
-struct ChalkContext<'a> {
-    db: &'a dyn HirDatabase,
-    krate: CrateId,
+pub(crate) struct ChalkContext<'a> {
+    pub(crate) db: &'a dyn HirDatabase,
+    pub(crate) krate: CrateId,
 }
 
 fn create_chalk_solver() -> chalk_recursive::RecursiveSolver<Interner> {
@@ -148,7 +146,7 @@ fn solve(
     // don't set the TLS for Chalk unless Chalk debugging is active, to make
     // extra sure we only use it for debugging
     let solution =
-        if is_chalk_debug() { chalk::tls::set_current_program(db, solve) } else { solve() };
+        if is_chalk_debug() { crate::tls::set_current_program(db, solve) } else { solve() };
 
     solution
 }
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
deleted file mode 100644
index 7818f6387..000000000
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ /dev/null
@@ -1,131 +0,0 @@
-//! This module contains the implementations of the `ToChalk` trait, which
-//! handles conversion between our data types and their corresponding types in
-//! Chalk (in both directions); plus some helper functions for more specialized
-//! conversions.
-
-use chalk_ir::cast::Cast;
-use chalk_solve::rust_ir;
-
-use base_db::salsa::InternKey;
-use hir_def::{GenericDefId, TypeAliasId};
-
-use crate::{
-    db::HirDatabase, AliasTy, CallableDefId, ProjectionTyExt, QuantifiedWhereClause, Substitution,
-    Ty, WhereClause,
-};
-
-use super::interner::*;
-use super::*;
-
-impl ToChalk for hir_def::TraitId {
-    type Chalk = TraitId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> TraitId {
-        chalk_ir::TraitId(self.as_intern_id())
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, trait_id: TraitId) -> hir_def::TraitId {
-        InternKey::from_intern_id(trait_id.0)
-    }
-}
-
-impl ToChalk for hir_def::ImplId {
-    type Chalk = ImplId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> ImplId {
-        chalk_ir::ImplId(self.as_intern_id())
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, impl_id: ImplId) -> hir_def::ImplId {
-        InternKey::from_intern_id(impl_id.0)
-    }
-}
-
-impl ToChalk for CallableDefId {
-    type Chalk = FnDefId;
-
-    fn to_chalk(self, db: &dyn HirDatabase) -> FnDefId {
-        db.intern_callable_def(self).into()
-    }
-
-    fn from_chalk(db: &dyn HirDatabase, fn_def_id: FnDefId) -> CallableDefId {
-        db.lookup_intern_callable_def(fn_def_id.into())
-    }
-}
-
-pub(crate) struct TypeAliasAsValue(pub(crate) TypeAliasId);
-
-impl ToChalk for TypeAliasAsValue {
-    type Chalk = AssociatedTyValueId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> AssociatedTyValueId {
-        rust_ir::AssociatedTyValueId(self.0.as_intern_id())
-    }
-
-    fn from_chalk(
-        _db: &dyn HirDatabase,
-        assoc_ty_value_id: AssociatedTyValueId,
-    ) -> TypeAliasAsValue {
-        TypeAliasAsValue(TypeAliasId::from_intern_id(assoc_ty_value_id.0))
-    }
-}
-
-pub(super) fn convert_where_clauses(
-    db: &dyn HirDatabase,
-    def: GenericDefId,
-    substs: &Substitution,
-) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
-    let generic_predicates = db.generic_predicates(def);
-    let mut result = Vec::with_capacity(generic_predicates.len());
-    for pred in generic_predicates.iter() {
-        result.push(pred.clone().substitute(&Interner, substs));
-    }
-    result
-}
-
-pub(super) fn generic_predicate_to_inline_bound(
-    db: &dyn HirDatabase,
-    pred: &QuantifiedWhereClause,
-    self_ty: &Ty,
-) -> Option<chalk_ir::Binders<rust_ir::InlineBound<Interner>>> {
-    // An InlineBound is like a GenericPredicate, except the self type is left out.
-    // We don't have a special type for this, but Chalk does.
-    let self_ty_shifted_in = self_ty.clone().shifted_in_from(&Interner, DebruijnIndex::ONE);
-    let (pred, binders) = pred.as_ref().into_value_and_skipped_binders();
-    match pred {
-        WhereClause::Implemented(trait_ref) => {
-            if trait_ref.self_type_parameter(&Interner) != self_ty_shifted_in {
-                // we can only convert predicates back to type bounds if they
-                // have the expected self type
-                return None;
-            }
-            let args_no_self = trait_ref.substitution.interned()[1..]
-                .iter()
-                .map(|ty| ty.clone().cast(&Interner))
-                .collect();
-            let trait_bound = rust_ir::TraitBound { trait_id: trait_ref.trait_id, args_no_self };
-            Some(chalk_ir::Binders::new(binders, rust_ir::InlineBound::TraitBound(trait_bound)))
-        }
-        WhereClause::AliasEq(AliasEq { alias: AliasTy::Projection(projection_ty), ty }) => {
-            if projection_ty.self_type_parameter(&Interner) != self_ty_shifted_in {
-                return None;
-            }
-            let trait_ = projection_ty.trait_(db);
-            let args_no_self = projection_ty.substitution.interned()[1..]
-                .iter()
-                .map(|ty| ty.clone().cast(&Interner))
-                .collect();
-            let alias_eq_bound = rust_ir::AliasEqBound {
-                value: ty.clone(),
-                trait_bound: rust_ir::TraitBound { trait_id: trait_.to_chalk(db), args_no_self },
-                associated_ty_id: projection_ty.associated_ty_id,
-                parameters: Vec::new(), // FIXME we don't support generic associated types yet
-            };
-            Some(chalk_ir::Binders::new(
-                binders,
-                rust_ir::InlineBound::AliasEqBound(alias_eq_bound),
-            ))
-        }
-        _ => None,
-    }
-}
diff --git a/crates/ide/src/diagnostics.rs b/crates/ide/src/diagnostics.rs
index dd42116a7..9a883acb9 100644
--- a/crates/ide/src/diagnostics.rs
+++ b/crates/ide/src/diagnostics.rs
@@ -20,12 +20,12 @@ use itertools::Itertools;
 use rustc_hash::FxHashSet;
 use syntax::{
     ast::{self, AstNode},
-    SyntaxNode, SyntaxNodePtr, TextRange,
+    SyntaxNode, SyntaxNodePtr, TextRange, TextSize,
 };
 use text_edit::TextEdit;
 use unlinked_file::UnlinkedFile;
 
-use crate::{FileId, Label, SourceChange};
+use crate::{Assist, AssistId, AssistKind, FileId, Label, SourceChange};
 
 use self::fixes::DiagnosticWithFix;
 
@@ -35,7 +35,7 @@ pub struct Diagnostic {
     pub message: String,
     pub range: TextRange,
     pub severity: Severity,
-    pub fix: Option<Fix>,
+    pub fix: Option<Assist>,
     pub unused: bool,
     pub code: Option<DiagnosticCode>,
 }
@@ -56,7 +56,7 @@ impl Diagnostic {
         }
     }
 
-    fn with_fix(self, fix: Option<Fix>) -> Self {
+    fn with_fix(self, fix: Option<Assist>) -> Self {
         Self { fix, ..self }
     }
 
@@ -69,21 +69,6 @@ impl Diagnostic {
     }
 }
 
-#[derive(Debug)]
-pub struct Fix {
-    pub label: Label,
-    pub source_change: SourceChange,
-    /// Allows to trigger the fix only when the caret is in the range given
-    pub fix_trigger_range: TextRange,
-}
-
-impl Fix {
-    fn new(label: &str, source_change: SourceChange, fix_trigger_range: TextRange) -> Self {
-        let label = Label::new(label);
-        Self { label, source_change, fix_trigger_range }
-    }
-}
-
 #[derive(Debug, Copy, Clone)]
 pub enum Severity {
     Error,
@@ -99,6 +84,7 @@ pub struct DiagnosticsConfig {
 pub(crate) fn diagnostics(
     db: &RootDatabase,
     config: &DiagnosticsConfig,
+    resolve: bool,
     file_id: FileId,
 ) -> Vec<Diagnostic> {
     let _p = profile::span("diagnostics");
@@ -122,25 +108,25 @@ pub(crate) fn diagnostics(
     let res = RefCell::new(res);
     let sink_builder = DiagnosticSinkBuilder::new()
         .on::<hir::diagnostics::UnresolvedModule, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema));
+            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::MissingFields, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema));
+            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::MissingOkOrSomeInTailExpr, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema));
+            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::NoSuchField, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema));
+            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::RemoveThisSemicolon, _>(|d| {
-            res.borrow_mut().push(diagnostic_with_fix(d, &sema));
+            res.borrow_mut().push(diagnostic_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::IncorrectCase, _>(|d| {
-            res.borrow_mut().push(warning_with_fix(d, &sema));
+            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::ReplaceFilterMapNextWithFindMap, _>(|d| {
-            res.borrow_mut().push(warning_with_fix(d, &sema));
+            res.borrow_mut().push(warning_with_fix(d, &sema, resolve));
         })
         .on::<hir::diagnostics::InactiveCode, _>(|d| {
             // If there's inactive code somewhere in a macro, don't propagate to the call-site.
@@ -159,14 +145,16 @@ pub(crate) fn diagnostics(
             );
         })
         .on::<UnlinkedFile, _>(|d| {
+            // Limit diagnostic to the first few characters in the file. This matches how VS Code
+            // renders it with the full span, but on other editors, and is less invasive.
+            let range = sema.diagnostics_display_range(d.display_source()).range;
+            let range = range.intersect(TextRange::up_to(TextSize::of("..."))).unwrap_or(range);
+
             // Override severity and mark as unused.
             res.borrow_mut().push(
-                Diagnostic::hint(
-                    sema.diagnostics_display_range(d.display_source()).range,
-                    d.message(),
-                )
-                .with_fix(d.fix(&sema))
-                .with_code(Some(d.code())),
+                Diagnostic::hint(range, d.message())
+                    .with_fix(d.fix(&sema, resolve))
+                    .with_code(Some(d.code())),
             );
         })
         .on::<hir::diagnostics::UnresolvedProcMacro, _>(|d| {
@@ -221,15 +209,23 @@ pub(crate) fn diagnostics(
     res.into_inner()
 }
 
-fn diagnostic_with_fix<D: DiagnosticWithFix>(d: &D, sema: &Semantics<RootDatabase>) -> Diagnostic {
+fn diagnostic_with_fix<D: DiagnosticWithFix>(
+    d: &D,
+    sema: &Semantics<RootDatabase>,
+    resolve: bool,
+) -> Diagnostic {
     Diagnostic::error(sema.diagnostics_display_range(d.display_source()).range, d.message())
-        .with_fix(d.fix(&sema))
+        .with_fix(d.fix(&sema, resolve))
         .with_code(Some(d.code()))
 }
 
-fn warning_with_fix<D: DiagnosticWithFix>(d: &D, sema: &Semantics<RootDatabase>) -> Diagnostic {
+fn warning_with_fix<D: DiagnosticWithFix>(
+    d: &D,
+    sema: &Semantics<RootDatabase>,
+    resolve: bool,
+) -> Diagnostic {
     Diagnostic::hint(sema.diagnostics_display_range(d.display_source()).range, d.message())
-        .with_fix(d.fix(&sema))
+        .with_fix(d.fix(&sema, resolve))
         .with_code(Some(d.code()))
 }
 
@@ -259,7 +255,8 @@ fn check_unnecessary_braces_in_use_statement(
 
         acc.push(
             Diagnostic::hint(use_range, "Unnecessary braces in use statement".to_string())
-                .with_fix(Some(Fix::new(
+                .with_fix(Some(fix(
+                    "remove_braces",
                     "Remove unnecessary braces",
                     SourceChange::from_text_edit(file_id, edit),
                     use_range,
@@ -282,6 +279,23 @@ fn text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(
     None
 }
 
+fn fix(id: &'static str, label: &str, source_change: SourceChange, target: TextRange) -> Assist {
+    let mut res = unresolved_fix(id, label, target);
+    res.source_change = Some(source_change);
+    res
+}
+
+fn unresolved_fix(id: &'static str, label: &str, target: TextRange) -> Assist {
+    assert!(!id.contains(' '));
+    Assist {
+        id: AssistId(id, AssistKind::QuickFix),
+        label: Label::new(label),
+        group: None,
+        target,
+        source_change: None,
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use expect_test::{expect, Expect};
@@ -300,16 +314,17 @@ mod tests {
 
         let (analysis, file_position) = fixture::position(ra_fixture_before);
         let diagnostic = analysis
-            .diagnostics(&DiagnosticsConfig::default(), file_position.file_id)
+            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
             .unwrap()
             .pop()
             .unwrap();
         let fix = diagnostic.fix.unwrap();
         let actual = {
-            let file_id = *fix.source_change.source_file_edits.keys().next().unwrap();
+            let source_change = fix.source_change.unwrap();
+            let file_id = *source_change.source_file_edits.keys().next().unwrap();
             let mut actual = analysis.file_text(file_id).unwrap().to_string();
 
-            for edit in fix.source_change.source_file_edits.values() {
+            for edit in source_change.source_file_edits.values() {
                 edit.apply(&mut actual);
             }
             actual
@@ -317,9 +332,9 @@ mod tests {
 
         assert_eq_text!(&after, &actual);
         assert!(
-            fix.fix_trigger_range.contains_inclusive(file_position.offset),
+            fix.target.contains_inclusive(file_position.offset),
             "diagnostic fix range {:?} does not touch cursor position {:?}",
-            fix.fix_trigger_range,
+            fix.target,
             file_position.offset
         );
     }
@@ -328,7 +343,7 @@ mod tests {
     fn check_no_fix(ra_fixture: &str) {
         let (analysis, file_position) = fixture::position(ra_fixture);
         let diagnostic = analysis
-            .diagnostics(&DiagnosticsConfig::default(), file_position.file_id)
+            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
             .unwrap()
             .pop()
             .unwrap();
@@ -342,7 +357,7 @@ mod tests {
         let diagnostics = files
             .into_iter()
             .flat_map(|file_id| {
-                analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap()
+                analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap()
             })
             .collect::<Vec<_>>();
         assert_eq!(diagnostics.len(), 0, "unexpected diagnostics:\n{:#?}", diagnostics);
@@ -350,7 +365,8 @@ mod tests {
 
     fn check_expect(ra_fixture: &str, expect: Expect) {
         let (analysis, file_id) = fixture::file(ra_fixture);
-        let diagnostics = analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap();
+        let diagnostics =
+            analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap();
         expect.assert_debug_eq(&diagnostics)
     }
 
@@ -663,24 +679,31 @@ fn test_fn() {
                         range: 0..8,
                         severity: Error,
                         fix: Some(
-                            Fix {
+                            Assist {
+                                id: AssistId(
+                                    "create_module",
+                                    QuickFix,
+                                ),
                                 label: "Create module",
-                                source_change: SourceChange {
-                                    source_file_edits: {},
-                                    file_system_edits: [
-                                        CreateFile {
-                                            dst: AnchoredPathBuf {
-                                                anchor: FileId(
-                                                    0,
-                                                ),
-                                                path: "foo.rs",
+                                group: None,
+                                target: 0..8,
+                                source_change: Some(
+                                    SourceChange {
+                                        source_file_edits: {},
+                                        file_system_edits: [
+                                            CreateFile {
+                                                dst: AnchoredPathBuf {
+                                                    anchor: FileId(
+                                                        0,
+                                                    ),
+                                                    path: "foo.rs",
+                                                },
+                                                initial_contents: "",
                                             },
-                                            initial_contents: "",
-                                        },
-                                    ],
-                                    is_snippet: false,
-                                },
-                                fix_trigger_range: 0..8,
+                                        ],
+                                        is_snippet: false,
+                                    },
+                                ),
                             },
                         ),
                         unused: false,
@@ -888,10 +911,11 @@ struct Foo {
 
         let (analysis, file_id) = fixture::file(r#"mod foo;"#);
 
-        let diagnostics = analysis.diagnostics(&config, file_id).unwrap();
+        let diagnostics = analysis.diagnostics(&config, true, file_id).unwrap();
         assert!(diagnostics.is_empty());
 
-        let diagnostics = analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap();
+        let diagnostics =
+            analysis.diagnostics(&DiagnosticsConfig::default(), true, file_id).unwrap();
         assert!(!diagnostics.is_empty());
     }
 
@@ -997,8 +1021,9 @@ impl TestStruct {
         let expected = r#"fn foo() {}"#;
 
         let (analysis, file_position) = fixture::position(input);
-        let diagnostics =
-            analysis.diagnostics(&DiagnosticsConfig::default(), file_position.file_id).unwrap();
+        let diagnostics = analysis
+            .diagnostics(&DiagnosticsConfig::default(), true, file_position.file_id)
+            .unwrap();
         assert_eq!(diagnostics.len(), 1);
 
         check_fix(input, expected);
diff --git a/crates/ide/src/diagnostics/field_shorthand.rs b/crates/ide/src/diagnostics/field_shorthand.rs
index 5c89e2170..2b1787f9b 100644
--- a/crates/ide/src/diagnostics/field_shorthand.rs
+++ b/crates/ide/src/diagnostics/field_shorthand.rs
@@ -5,7 +5,7 @@ use ide_db::{base_db::FileId, source_change::SourceChange};
 use syntax::{ast, match_ast, AstNode, SyntaxNode};
 use text_edit::TextEdit;
 
-use crate::{Diagnostic, Fix};
+use crate::{diagnostics::fix, Diagnostic};
 
 pub(super) fn check(acc: &mut Vec<Diagnostic>, file_id: FileId, node: &SyntaxNode) {
     match_ast! {
@@ -47,7 +47,8 @@ fn check_expr_field_shorthand(
         let field_range = record_field.syntax().text_range();
         acc.push(
             Diagnostic::hint(field_range, "Shorthand struct initialization".to_string()).with_fix(
-                Some(Fix::new(
+                Some(fix(
+                    "use_expr_field_shorthand",
                     "Use struct shorthand initialization",
                     SourceChange::from_text_edit(file_id, edit),
                     field_range,
@@ -86,7 +87,8 @@ fn check_pat_field_shorthand(
 
         let field_range = record_pat_field.syntax().text_range();
         acc.push(Diagnostic::hint(field_range, "Shorthand struct pattern".to_string()).with_fix(
-            Some(Fix::new(
+            Some(fix(
+                "use_pat_field_shorthand",
                 "Use struct field shorthand",
                 SourceChange::from_text_edit(file_id, edit),
                 field_range,
diff --git a/crates/ide/src/diagnostics/fixes.rs b/crates/ide/src/diagnostics/fixes.rs
index 5fb3e2d91..7be8b3459 100644
--- a/crates/ide/src/diagnostics/fixes.rs
+++ b/crates/ide/src/diagnostics/fixes.rs
@@ -20,20 +20,30 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::{diagnostics::Fix, references::rename::rename_with_semantics, FilePosition};
+use crate::{
+    diagnostics::{fix, unresolved_fix},
+    references::rename::rename_with_semantics,
+    Assist, FilePosition,
+};
 
 /// A [Diagnostic] that potentially has a fix available.
 ///
 /// [Diagnostic]: hir::diagnostics::Diagnostic
 pub(crate) trait DiagnosticWithFix: Diagnostic {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix>;
+    /// `resolve` determines if the diagnostic should fill in the `edit` field
+    /// of the assist.
+    ///
+    /// If `resolve` is false, the edit will be computed later, on demand, and
+    /// can be omitted.
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist>;
 }
 
 impl DiagnosticWithFix for UnresolvedModule {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let unresolved_module = self.decl.to_node(&root);
-        Some(Fix::new(
+        Some(fix(
+            "create_module",
             "Create module",
             FileSystemEdit::CreateFile {
                 dst: AnchoredPathBuf {
@@ -49,7 +59,7 @@ impl DiagnosticWithFix for UnresolvedModule {
 }
 
 impl DiagnosticWithFix for NoSuchField {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         missing_record_expr_field_fix(
             &sema,
@@ -60,7 +70,7 @@ impl DiagnosticWithFix for NoSuchField {
 }
 
 impl DiagnosticWithFix for MissingFields {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         // Note that although we could add a diagnostics to
         // fill the missing tuple field, e.g :
         // `struct A(usize);`
@@ -86,7 +96,8 @@ impl DiagnosticWithFix for MissingFields {
                 .into_text_edit(&mut builder);
             builder.finish()
         };
-        Some(Fix::new(
+        Some(fix(
+            "fill_missing_fields",
             "Fill struct fields",
             SourceChange::from_text_edit(self.file.original_file(sema.db), edit),
             sema.original_range(&field_list_parent.syntax()).range,
@@ -95,7 +106,7 @@ impl DiagnosticWithFix for MissingFields {
 }
 
 impl DiagnosticWithFix for MissingOkOrSomeInTailExpr {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let tail_expr = self.expr.to_node(&root);
         let tail_expr_range = tail_expr.syntax().text_range();
@@ -103,12 +114,12 @@ impl DiagnosticWithFix for MissingOkOrSomeInTailExpr {
         let edit = TextEdit::replace(tail_expr_range, replacement);
         let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
         let name = if self.required == "Ok" { "Wrap with Ok" } else { "Wrap with Some" };
-        Some(Fix::new(name, source_change, tail_expr_range))
+        Some(fix("wrap_tail_expr", name, source_change, tail_expr_range))
     }
 }
 
 impl DiagnosticWithFix for RemoveThisSemicolon {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
 
         let semicolon = self
@@ -123,12 +134,12 @@ impl DiagnosticWithFix for RemoveThisSemicolon {
         let edit = TextEdit::delete(semicolon);
         let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
 
-        Some(Fix::new("Remove this semicolon", source_change, semicolon))
+        Some(fix("remove_semicolon", "Remove this semicolon", source_change, semicolon))
     }
 }
 
 impl DiagnosticWithFix for IncorrectCase {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let name_node = self.ident.to_node(&root);
 
@@ -136,16 +147,19 @@ impl DiagnosticWithFix for IncorrectCase {
         let frange = name_node.original_file_range(sema.db);
         let file_position = FilePosition { file_id: frange.file_id, offset: frange.range.start() };
 
-        let rename_changes =
-            rename_with_semantics(sema, file_position, &self.suggested_text).ok()?;
-
         let label = format!("Rename to {}", self.suggested_text);
-        Some(Fix::new(&label, rename_changes, frange.range))
+        let mut res = unresolved_fix("change_case", &label, frange.range);
+        if resolve {
+            let source_change = rename_with_semantics(sema, file_position, &self.suggested_text);
+            res.source_change = Some(source_change.ok().unwrap_or_default());
+        }
+
+        Some(res)
     }
 }
 
 impl DiagnosticWithFix for ReplaceFilterMapNextWithFindMap {
-    fn fix(&self, sema: &Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         let root = sema.db.parse_or_expand(self.file)?;
         let next_expr = self.next_expr.to_node(&root);
         let next_call = ast::MethodCallExpr::cast(next_expr.syntax().clone())?;
@@ -163,7 +177,8 @@ impl DiagnosticWithFix for ReplaceFilterMapNextWithFindMap {
 
         let source_change = SourceChange::from_text_edit(self.file.original_file(sema.db), edit);
 
-        Some(Fix::new(
+        Some(fix(
+            "replace_with_find_map",
             "Replace filter_map(..).next() with find_map()",
             source_change,
             trigger_range,
@@ -175,7 +190,7 @@ fn missing_record_expr_field_fix(
     sema: &Semantics<RootDatabase>,
     usage_file_id: FileId,
     record_expr_field: &ast::RecordExprField,
-) -> Option<Fix> {
+) -> Option<Assist> {
     let record_lit = ast::RecordExpr::cast(record_expr_field.syntax().parent()?.parent()?)?;
     let def_id = sema.resolve_variant(record_lit)?;
     let module;
@@ -233,7 +248,12 @@ fn missing_record_expr_field_fix(
         def_file_id,
         TextEdit::insert(last_field_syntax.text_range().end(), new_field),
     );
-    return Some(Fix::new("Create field", source_change, record_expr_field.syntax().text_range()));
+    return Some(fix(
+        "create_field",
+        "Create field",
+        source_change,
+        record_expr_field.syntax().text_range(),
+    ));
 
     fn record_field_list(field_def_list: ast::FieldList) -> Option<ast::RecordFieldList> {
         match field_def_list {
diff --git a/crates/ide/src/diagnostics/unlinked_file.rs b/crates/ide/src/diagnostics/unlinked_file.rs
index e174fb767..7d39f4fbe 100644
--- a/crates/ide/src/diagnostics/unlinked_file.rs
+++ b/crates/ide/src/diagnostics/unlinked_file.rs
@@ -16,9 +16,10 @@ use syntax::{
 };
 use text_edit::TextEdit;
 
-use crate::Fix;
-
-use super::fixes::DiagnosticWithFix;
+use crate::{
+    diagnostics::{fix, fixes::DiagnosticWithFix},
+    Assist,
+};
 
 // Diagnostic: unlinked-file
 //
@@ -49,7 +50,7 @@ impl Diagnostic for UnlinkedFile {
 }
 
 impl DiagnosticWithFix for UnlinkedFile {
-    fn fix(&self, sema: &hir::Semantics<RootDatabase>) -> Option<Fix> {
+    fn fix(&self, sema: &hir::Semantics<RootDatabase>, _resolve: bool) -> Option<Assist> {
         // If there's an existing module that could add a `mod` item to include the unlinked file,
         // suggest that as a fix.
 
@@ -100,7 +101,7 @@ fn make_fix(
     parent_file_id: FileId,
     new_mod_name: &str,
     added_file_id: FileId,
-) -> Option<Fix> {
+) -> Option<Assist> {
     fn is_outline_mod(item: &ast::Item) -> bool {
         matches!(item, ast::Item::Module(m) if m.item_list().is_none())
     }
@@ -152,7 +153,8 @@ fn make_fix(
 
     let edit = builder.finish();
     let trigger_range = db.parse(added_file_id).tree().syntax().text_range();
-    Some(Fix::new(
+    Some(fix(
+        "add_mod_declaration",
         &format!("Insert `{}`", mod_decl),
         SourceChange::from_text_edit(parent_file_id, edit),
         trigger_range,
diff --git a/crates/ide/src/goto_definition.rs b/crates/ide/src/goto_definition.rs
index ca8ccb2da..a04333e63 100644
--- a/crates/ide/src/goto_definition.rs
+++ b/crates/ide/src/goto_definition.rs
@@ -110,6 +110,13 @@ mod tests {
         assert_eq!(expected, FileRange { file_id: nav.file_id, range: nav.focus_or_full_range() });
     }
 
+    fn check_unresolved(ra_fixture: &str) {
+        let (analysis, position) = fixture::position(ra_fixture);
+        let navs = analysis.goto_definition(position).unwrap().expect("no definition found").info;
+
+        assert!(navs.is_empty(), "didn't expect this to resolve anywhere: {:?}", navs)
+    }
+
     #[test]
     fn goto_def_for_extern_crate() {
         check(
@@ -927,17 +934,12 @@ fn f() -> impl Iterator<Item$0 = u8> {}
     }
 
     #[test]
-    #[should_panic = "unresolved reference"]
     fn unknown_assoc_ty() {
-        check(
+        check_unresolved(
             r#"
-trait Iterator {
-    type Item;
-       //^^^^
-}
-
+trait Iterator { type Item; }
 fn f() -> impl Iterator<Invalid$0 = u8> {}
-            "#,
+"#,
         )
     }
 
@@ -1188,4 +1190,30 @@ pub fn gimme() -> theitem::TheItem {
 "#,
         );
     }
+
+    #[test]
+    fn goto_ident_from_pat_macro() {
+        check(
+            r#"
+macro_rules! pat {
+    ($name:ident) => { Enum::Variant1($name) }
+}
+
+enum Enum {
+    Variant1(u8),
+    Variant2,
+}
+
+fn f(e: Enum) {
+    match e {
+        pat!(bind) => {
+           //^^^^
+            bind$0
+        }
+        Enum::Variant2 => {}
+    }
+}
+"#,
+        );
+    }
 }
diff --git a/crates/ide/src/lib.rs b/crates/ide/src/lib.rs
index b5ae51d28..b24c664ba 100644
--- a/crates/ide/src/lib.rs
+++ b/crates/ide/src/lib.rs
@@ -69,7 +69,7 @@ use crate::display::ToNav;
 pub use crate::{
     annotations::{Annotation, AnnotationConfig, AnnotationKind},
     call_hierarchy::CallItem,
-    diagnostics::{Diagnostic, DiagnosticsConfig, Fix, Severity},
+    diagnostics::{Diagnostic, DiagnosticsConfig, Severity},
     display::navigation_target::NavigationTarget,
     expand_macro::ExpandedMacro,
     file_structure::{StructureNode, StructureNodeKind},
@@ -526,9 +526,39 @@ impl Analysis {
     pub fn diagnostics(
         &self,
         config: &DiagnosticsConfig,
+        resolve: bool,
         file_id: FileId,
     ) -> Cancelable<Vec<Diagnostic>> {
-        self.with_db(|db| diagnostics::diagnostics(db, config, file_id))
+        self.with_db(|db| diagnostics::diagnostics(db, config, resolve, file_id))
+    }
+
+    /// Convenience function to return assists + quick fixes for diagnostics
+    pub fn assists_with_fixes(
+        &self,
+        assist_config: &AssistConfig,
+        diagnostics_config: &DiagnosticsConfig,
+        resolve: bool,
+        frange: FileRange,
+    ) -> Cancelable<Vec<Assist>> {
+        let include_fixes = match &assist_config.allowed {
+            Some(it) => it.iter().any(|&it| it == AssistKind::None || it == AssistKind::QuickFix),
+            None => true,
+        };
+
+        self.with_db(|db| {
+            let mut res = Assist::get(db, assist_config, resolve, frange);
+            ssr::add_ssr_assist(db, &mut res, resolve, frange);
+
+            if include_fixes {
+                res.extend(
+                    diagnostics::diagnostics(db, diagnostics_config, resolve, frange.file_id)
+                        .into_iter()
+                        .filter_map(|it| it.fix)
+                        .filter(|it| it.target.intersect(frange.range).is_some()),
+                );
+            }
+            res
+        })
     }
 
     /// Returns the edit required to rename reference at the position to the new
diff --git a/crates/ide/src/syntax_highlighting/highlight.rs b/crates/ide/src/syntax_highlighting/highlight.rs
index 8dd5d801b..8cc877c1c 100644
--- a/crates/ide/src/syntax_highlighting/highlight.rs
+++ b/crates/ide/src/syntax_highlighting/highlight.rs
@@ -358,8 +358,18 @@ fn highlight_def(db: &RootDatabase, def: Definition) -> Highlight {
             hir::ModuleDef::Trait(_) => HlTag::Symbol(SymbolKind::Trait),
             hir::ModuleDef::TypeAlias(type_) => {
                 let mut h = Highlight::new(HlTag::Symbol(SymbolKind::TypeAlias));
-                if type_.as_assoc_item(db).is_some() {
-                    h |= HlMod::Associated
+                if let Some(item) = type_.as_assoc_item(db) {
+                    h |= HlMod::Associated;
+                    match item.container(db) {
+                        AssocItemContainer::Impl(i) => {
+                            if i.trait_(db).is_some() {
+                                h |= HlMod::Trait;
+                            }
+                        }
+                        AssocItemContainer::Trait(_t) => {
+                            h |= HlMod::Trait;
+                        }
+                    }
                 }
                 return h;
             }
diff --git a/crates/ide/src/syntax_highlighting/tests.rs b/crates/ide/src/syntax_highlighting/tests.rs
index 1b02857ec..933cfa6f3 100644
--- a/crates/ide/src/syntax_highlighting/tests.rs
+++ b/crates/ide/src/syntax_highlighting/tests.rs
@@ -1,6 +1,8 @@
+use std::time::Instant;
+
 use expect_test::{expect_file, ExpectFile};
 use ide_db::SymbolKind;
-use test_utils::{bench, bench_fixture, skip_slow_tests};
+use test_utils::{bench, bench_fixture, skip_slow_tests, AssertLinear};
 
 use crate::{fixture, FileRange, HlTag, TextRange};
 
@@ -258,6 +260,36 @@ fn benchmark_syntax_highlighting_long_struct() {
 }
 
 #[test]
+fn syntax_highlighting_not_quadratic() {
+    if skip_slow_tests() {
+        return;
+    }
+
+    let mut al = AssertLinear::default();
+    while al.next_round() {
+        for i in 6..=10 {
+            let n = 1 << i;
+
+            let fixture = bench_fixture::big_struct_n(n);
+            let (analysis, file_id) = fixture::file(&fixture);
+
+            let time = Instant::now();
+
+            let hash = analysis
+                .highlight(file_id)
+                .unwrap()
+                .iter()
+                .filter(|it| it.highlight.tag == HlTag::Symbol(SymbolKind::Struct))
+                .count();
+            assert!(hash > n as usize);
+
+            let elapsed = time.elapsed();
+            al.sample(n as f64, elapsed.as_millis() as f64);
+        }
+    }
+}
+
+#[test]
 fn benchmark_syntax_highlighting_parser() {
     if skip_slow_tests() {
         return;
diff --git a/crates/ide/src/typing/on_enter.rs b/crates/ide/src/typing/on_enter.rs
index 9144681bf..7d2db201a 100644
--- a/crates/ide/src/typing/on_enter.rs
+++ b/crates/ide/src/typing/on_enter.rs
@@ -4,10 +4,11 @@
 use ide_db::base_db::{FilePosition, SourceDatabase};
 use ide_db::RootDatabase;
 use syntax::{
-    ast::{self, AstToken},
+    algo::find_node_at_offset,
+    ast::{self, edit::IndentLevel, AstToken},
     AstNode, SmolStr, SourceFile,
     SyntaxKind::*,
-    SyntaxToken, TextRange, TextSize, TokenAtOffset,
+    SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset,
 };
 
 use text_edit::TextEdit;
@@ -18,6 +19,8 @@ use text_edit::TextEdit;
 //
 // - kbd:[Enter] inside triple-slash comments automatically inserts `///`
 // - kbd:[Enter] in the middle or after a trailing space in `//` inserts `//`
+// - kbd:[Enter] inside `//!` doc comments automatically inserts `//!`
+// - kbd:[Enter] after `{` indents contents and closing `}` of single-line block
 //
 // This action needs to be assigned to shortcut explicitly.
 //
@@ -37,25 +40,43 @@ use text_edit::TextEdit;
 pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<TextEdit> {
     let parse = db.parse(position.file_id);
     let file = parse.tree();
-    let comment = file
-        .syntax()
-        .token_at_offset(position.offset)
-        .left_biased()
-        .and_then(ast::Comment::cast)?;
+    let token = file.syntax().token_at_offset(position.offset).left_biased()?;
 
+    if let Some(comment) = ast::Comment::cast(token.clone()) {
+        return on_enter_in_comment(&comment, &file, position.offset);
+    }
+
+    if token.kind() == L_CURLY {
+        // Typing enter after the `{` of a block expression, where the `}` is on the same line
+        if let Some(edit) = find_node_at_offset(file.syntax(), position.offset - TextSize::of('{'))
+            .and_then(|block| on_enter_in_block(block, position))
+        {
+            cov_mark::hit!(indent_block_contents);
+            return Some(edit);
+        }
+    }
+
+    None
+}
+
+fn on_enter_in_comment(
+    comment: &ast::Comment,
+    file: &ast::SourceFile,
+    offset: TextSize,
+) -> Option<TextEdit> {
     if comment.kind().shape.is_block() {
         return None;
     }
 
     let prefix = comment.prefix();
     let comment_range = comment.syntax().text_range();
-    if position.offset < comment_range.start() + TextSize::of(prefix) {
+    if offset < comment_range.start() + TextSize::of(prefix) {
         return None;
     }
 
     let mut remove_trailing_whitespace = false;
     // Continuing single-line non-doc comments (like this one :) ) is annoying
-    if prefix == "//" && comment_range.end() == position.offset {
+    if prefix == "//" && comment_range.end() == offset {
         if comment.text().ends_with(' ') {
             cov_mark::hit!(continues_end_of_line_comment_with_space);
             remove_trailing_whitespace = true;
@@ -69,14 +90,42 @@ pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<Text
     let delete = if remove_trailing_whitespace {
         let trimmed_len = comment.text().trim_end().len() as u32;
         let trailing_whitespace_len = comment.text().len() as u32 - trimmed_len;
-        TextRange::new(position.offset - TextSize::from(trailing_whitespace_len), position.offset)
+        TextRange::new(offset - TextSize::from(trailing_whitespace_len), offset)
     } else {
-        TextRange::empty(position.offset)
+        TextRange::empty(offset)
     };
     let edit = TextEdit::replace(delete, inserted);
     Some(edit)
 }
 
+fn on_enter_in_block(block: ast::BlockExpr, position: FilePosition) -> Option<TextEdit> {
+    let contents = block_contents(&block)?;
+
+    if block.syntax().text().contains_char('\n') {
+        return None;
+    }
+
+    let indent = IndentLevel::from_node(block.syntax());
+    let mut edit = TextEdit::insert(position.offset, format!("\n{}$0", indent + 1));
+    edit.union(TextEdit::insert(contents.text_range().end(), format!("\n{}", indent))).ok()?;
+    Some(edit)
+}
+
+fn block_contents(block: &ast::BlockExpr) -> Option<SyntaxNode> {
+    let mut node = block.tail_expr().map(|e| e.syntax().clone());
+
+    for stmt in block.statements() {
+        if node.is_some() {
+            // More than 1 node in the block
+            return None;
+        }
+
+        node = Some(stmt.syntax().clone());
+    }
+
+    node
+}
+
 fn followed_by_comment(comment: &ast::Comment) -> bool {
     let ws = match comment.syntax().next_token().and_then(ast::Whitespace::cast) {
         Some(it) => it,
@@ -187,6 +236,25 @@ fn foo() {
     }
 
     #[test]
+    fn continues_another_doc_comment() {
+        do_check(
+            r#"
+fn main() {
+    //! Documentation for$0 on enter
+    let x = 1 + 1;
+}
+"#,
+            r#"
+fn main() {
+    //! Documentation for
+    //! $0 on enter
+    let x = 1 + 1;
+}
+"#,
+        );
+    }
+
+    #[test]
     fn continues_code_comment_in_the_middle_of_line() {
         do_check(
             r"
@@ -276,4 +344,144 @@ fn main() {
 ",
         );
     }
+
+    #[test]
+    fn indents_fn_body_block() {
+        cov_mark::check!(indent_block_contents);
+        do_check(
+            r#"
+fn f() {$0()}
+        "#,
+            r#"
+fn f() {
+    $0()
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn indents_block_expr() {
+        do_check(
+            r#"
+fn f() {
+    let x = {$0()};
+}
+        "#,
+            r#"
+fn f() {
+    let x = {
+        $0()
+    };
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn indents_match_arm() {
+        do_check(
+            r#"
+fn f() {
+    match 6 {
+        1 => {$0f()},
+        _ => (),
+    }
+}
+        "#,
+            r#"
+fn f() {
+    match 6 {
+        1 => {
+            $0f()
+        },
+        _ => (),
+    }
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn indents_block_with_statement() {
+        do_check(
+            r#"
+fn f() {$0a = b}
+        "#,
+            r#"
+fn f() {
+    $0a = b
+}
+        "#,
+        );
+        do_check(
+            r#"
+fn f() {$0fn f() {}}
+        "#,
+            r#"
+fn f() {
+    $0fn f() {}
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn indents_nested_blocks() {
+        do_check(
+            r#"
+fn f() {$0{}}
+        "#,
+            r#"
+fn f() {
+    $0{}
+}
+        "#,
+        );
+    }
+
+    #[test]
+    fn does_not_indent_empty_block() {
+        do_check_noop(
+            r#"
+fn f() {$0}
+        "#,
+        );
+        do_check_noop(
+            r#"
+fn f() {{$0}}
+        "#,
+        );
+    }
+
+    #[test]
+    fn does_not_indent_block_with_too_much_content() {
+        do_check_noop(
+            r#"
+fn f() {$0 a = b; ()}
+        "#,
+        );
+        do_check_noop(
+            r#"
+fn f() {$0 a = b; a = b; }
+        "#,
+        );
+    }
+
+    #[test]
+    fn does_not_indent_multiline_block() {
+        do_check_noop(
+            r#"
+fn f() {$0
+}
+        "#,
+        );
+        do_check_noop(
+            r#"
+fn f() {$0
+
+}
+        "#,
+        );
+    }
 }
diff --git a/crates/ide_assists/src/handlers/extract_function.rs b/crates/ide_assists/src/handlers/extract_function.rs
index 5fdc8bf38..059414274 100644
--- a/crates/ide_assists/src/handlers/extract_function.rs
+++ b/crates/ide_assists/src/handlers/extract_function.rs
@@ -75,7 +75,8 @@ pub(crate) fn extract_function(acc: &mut Assists, ctx: &AssistContext) -> Option
     let insert_after = scope_for_fn_insertion(&body, anchor)?;
     let module = ctx.sema.scope(&insert_after).module()?;
 
-    let vars_defined_in_body_and_outlive = vars_defined_in_body_and_outlive(ctx, &body);
+    let vars_defined_in_body_and_outlive =
+        vars_defined_in_body_and_outlive(ctx, &body, &node.parent().as_ref().unwrap_or(&node));
     let ret_ty = body_return_ty(ctx, &body)?;
 
     // FIXME: we compute variables that outlive here just to check `never!` condition
@@ -257,7 +258,7 @@ struct Function {
     control_flow: ControlFlow,
     ret_ty: RetType,
     body: FunctionBody,
-    vars_defined_in_body_and_outlive: Vec<Local>,
+    vars_defined_in_body_and_outlive: Vec<OutlivedLocal>,
 }
 
 #[derive(Debug)]
@@ -296,9 +297,9 @@ impl Function {
             RetType::Expr(ty) => FunType::Single(ty.clone()),
             RetType::Stmt => match self.vars_defined_in_body_and_outlive.as_slice() {
                 [] => FunType::Unit,
-                [var] => FunType::Single(var.ty(ctx.db())),
+                [var] => FunType::Single(var.local.ty(ctx.db())),
                 vars => {
-                    let types = vars.iter().map(|v| v.ty(ctx.db())).collect();
+                    let types = vars.iter().map(|v| v.local.ty(ctx.db())).collect();
                     FunType::Tuple(types)
                 }
             },
@@ -562,6 +563,12 @@ impl HasTokenAtOffset for FunctionBody {
     }
 }
 
+#[derive(Debug)]
+struct OutlivedLocal {
+    local: Local,
+    mut_usage_outside_body: bool,
+}
+
 /// Try to guess what user wants to extract
 ///
 /// We have basically have two cases:
@@ -707,10 +714,10 @@ fn has_exclusive_usages(ctx: &AssistContext, usages: &LocalUsages, body: &Functi
         .any(|reference| reference_is_exclusive(reference, body, ctx))
 }
 
-/// checks if this reference requires `&mut` access inside body
+/// checks if this reference requires `&mut` access inside node
 fn reference_is_exclusive(
     reference: &FileReference,
-    body: &FunctionBody,
+    node: &dyn HasTokenAtOffset,
     ctx: &AssistContext,
 ) -> bool {
     // we directly modify variable with set: `n = 0`, `n += 1`
@@ -719,7 +726,7 @@ fn reference_is_exclusive(
     }
 
     // we take `&mut` reference to variable: `&mut v`
-    let path = match path_element_of_reference(body, reference) {
+    let path = match path_element_of_reference(node, reference) {
         Some(path) => path,
         None => return false,
     };
@@ -729,6 +736,14 @@ fn reference_is_exclusive(
 
 /// checks if this expr requires `&mut` access, recurses on field access
 fn expr_require_exclusive_access(ctx: &AssistContext, expr: &ast::Expr) -> Option<bool> {
+    match expr {
+        ast::Expr::MacroCall(_) => {
+            // FIXME: expand macro and check output for mutable usages of the variable?
+            return None;
+        }
+        _ => (),
+    }
+
     let parent = expr.syntax().parent()?;
 
     if let Some(bin_expr) = ast::BinExpr::cast(parent.clone()) {
@@ -787,7 +802,7 @@ impl HasTokenAtOffset for SyntaxNode {
     }
 }
 
-/// find relevant `ast::PathExpr` for reference
+/// find relevant `ast::Expr` for reference
 ///
 /// # Preconditions
 ///
@@ -804,7 +819,11 @@ fn path_element_of_reference(
         stdx::never!(false, "cannot find path parent of variable usage: {:?}", token);
         None
     })?;
-    stdx::always!(matches!(path, ast::Expr::PathExpr(_)));
+    stdx::always!(
+        matches!(path, ast::Expr::PathExpr(_) | ast::Expr::MacroCall(_)),
+        "unexpected expression type for variable usage: {:?}",
+        path
+    );
     Some(path)
 }
 
@@ -820,10 +839,16 @@ fn vars_defined_in_body(body: &FunctionBody, ctx: &AssistContext) -> Vec<Local>
 }
 
 /// list local variables defined inside `body` that should be returned from extracted function
-fn vars_defined_in_body_and_outlive(ctx: &AssistContext, body: &FunctionBody) -> Vec<Local> {
-    let mut vars_defined_in_body = vars_defined_in_body(&body, ctx);
-    vars_defined_in_body.retain(|var| var_outlives_body(ctx, body, var));
+fn vars_defined_in_body_and_outlive(
+    ctx: &AssistContext,
+    body: &FunctionBody,
+    parent: &SyntaxNode,
+) -> Vec<OutlivedLocal> {
+    let vars_defined_in_body = vars_defined_in_body(&body, ctx);
     vars_defined_in_body
+        .into_iter()
+        .filter_map(|var| var_outlives_body(ctx, body, var, parent))
+        .collect()
 }
 
 /// checks if the relevant local was defined before(outside of) body
@@ -843,11 +868,23 @@ fn either_syntax(value: &Either<ast::IdentPat, ast::SelfParam>) -> &SyntaxNode {
     }
 }
 
-/// checks if local variable is used after(outside of) body
-fn var_outlives_body(ctx: &AssistContext, body: &FunctionBody, var: &Local) -> bool {
-    let usages = LocalUsages::find(ctx, *var);
+/// returns usage details if local variable is used after(outside of) body
+fn var_outlives_body(
+    ctx: &AssistContext,
+    body: &FunctionBody,
+    var: Local,
+    parent: &SyntaxNode,
+) -> Option<OutlivedLocal> {
+    let usages = LocalUsages::find(ctx, var);
     let has_usages = usages.iter().any(|reference| body.preceedes_range(reference.range));
-    has_usages
+    if !has_usages {
+        return None;
+    }
+    let has_mut_usages = usages
+        .iter()
+        .filter(|reference| body.preceedes_range(reference.range))
+        .any(|reference| reference_is_exclusive(reference, parent, ctx));
+    Some(OutlivedLocal { local: var, mut_usage_outside_body: has_mut_usages })
 }
 
 fn body_return_ty(ctx: &AssistContext, body: &FunctionBody) -> Option<RetType> {
@@ -927,16 +964,25 @@ fn format_replacement(ctx: &AssistContext, fun: &Function, indent: IndentLevel)
     let mut buf = String::new();
     match fun.vars_defined_in_body_and_outlive.as_slice() {
         [] => {}
-        [var] => format_to!(buf, "let {} = ", var.name(ctx.db()).unwrap()),
+        [var] => {
+            format_to!(buf, "let {}{} = ", mut_modifier(var), var.local.name(ctx.db()).unwrap())
+        }
         [v0, vs @ ..] => {
             buf.push_str("let (");
-            format_to!(buf, "{}", v0.name(ctx.db()).unwrap());
+            format_to!(buf, "{}{}", mut_modifier(v0), v0.local.name(ctx.db()).unwrap());
             for var in vs {
-                format_to!(buf, ", {}", var.name(ctx.db()).unwrap());
+                format_to!(buf, ", {}{}", mut_modifier(var), var.local.name(ctx.db()).unwrap());
             }
             buf.push_str(") = ");
         }
     }
+    fn mut_modifier(var: &OutlivedLocal) -> &'static str {
+        if var.mut_usage_outside_body {
+            "mut "
+        } else {
+            ""
+        }
+    }
     format_to!(buf, "{}", expr);
     if fun.ret_ty.is_unit()
         && (!fun.vars_defined_in_body_and_outlive.is_empty() || !expr.is_block_like())
@@ -1199,10 +1245,10 @@ fn make_body(
                 match fun.vars_defined_in_body_and_outlive.as_slice() {
                     [] => {}
                     [var] => {
-                        tail_expr = Some(path_expr_from_local(ctx, *var));
+                        tail_expr = Some(path_expr_from_local(ctx, var.local));
                     }
                     vars => {
-                        let exprs = vars.iter().map(|var| path_expr_from_local(ctx, *var));
+                        let exprs = vars.iter().map(|var| path_expr_from_local(ctx, var.local));
                         let expr = make::expr_tuple(exprs);
                         tail_expr = Some(expr);
                     }
@@ -2111,6 +2157,30 @@ fn $0fun_name(n: i32) -> i32 {
     }
 
     #[test]
+    fn variable_defined_inside_and_used_after_mutably_no_ret() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let n = 1;
+    $0let mut k = n * n;$0
+    k += 1;
+}",
+            r"
+fn foo() {
+    let n = 1;
+    let mut k = fun_name(n);
+    k += 1;
+}
+
+fn $0fun_name(n: i32) -> i32 {
+    let mut k = n * n;
+    k
+}",
+        );
+    }
+
+    #[test]
     fn two_variables_defined_inside_and_used_after_no_ret() {
         check_assist(
             extract_function,
@@ -2137,6 +2207,38 @@ fn $0fun_name(n: i32) -> (i32, i32) {
     }
 
     #[test]
+    fn multi_variables_defined_inside_and_used_after_mutably_no_ret() {
+        check_assist(
+            extract_function,
+            r"
+fn foo() {
+    let n = 1;
+    $0let mut k = n * n;
+    let mut m = k + 2;
+    let mut o = m + 3;
+    o += 1;$0
+    k += o;
+    m = 1;
+}",
+            r"
+fn foo() {
+    let n = 1;
+    let (mut k, mut m, o) = fun_name(n);
+    k += o;
+    m = 1;
+}
+
+fn $0fun_name(n: i32) -> (i32, i32, i32) {
+    let mut k = n * n;
+    let mut m = k + 2;
+    let mut o = m + 3;
+    o += 1;
+    (k, m, o)
+}",
+        );
+    }
+
+    #[test]
     fn nontrivial_patterns_define_variables() {
         check_assist(
             extract_function,
@@ -3372,4 +3474,36 @@ fn foo() -> Result<(), i64> {
 }"##,
         );
     }
+
+    #[test]
+    fn param_usage_in_macro() {
+        check_assist(
+            extract_function,
+            r"
+macro_rules! m {
+    ($val:expr) => { $val };
+}
+
+fn foo() {
+    let n = 1;
+    $0let k = n * m!(n);$0
+    let m = k + 1;
+}",
+            r"
+macro_rules! m {
+    ($val:expr) => { $val };
+}
+
+fn foo() {
+    let n = 1;
+    let k = fun_name(n);
+    let m = k + 1;
+}
+
+fn $0fun_name(n: i32) -> i32 {
+    let k = n * m!(n);
+    k
+}",
+        );
+    }
 }
diff --git a/crates/ide_assists/src/handlers/flip_comma.rs b/crates/ide_assists/src/handlers/flip_comma.rs
index 7f5e75d34..99be5e090 100644
--- a/crates/ide_assists/src/handlers/flip_comma.rs
+++ b/crates/ide_assists/src/handlers/flip_comma.rs
@@ -66,26 +66,12 @@ mod tests {
     }
 
     #[test]
-    #[should_panic]
     fn flip_comma_before_punct() {
         // See https://github.com/rust-analyzer/rust-analyzer/issues/1619
         // "Flip comma" assist shouldn't be applicable to the last comma in enum or struct
         // declaration body.
-        check_assist_target(
-            flip_comma,
-            "pub enum Test { \
-             A,$0 \
-             }",
-            ",",
-        );
-
-        check_assist_target(
-            flip_comma,
-            "pub struct Test { \
-             foo: usize,$0 \
-             }",
-            ",",
-        );
+        check_assist_not_applicable(flip_comma, "pub enum Test { A,$0 }");
+        check_assist_not_applicable(flip_comma, "pub struct Test { foo: usize,$0 }");
     }
 
     #[test]
diff --git a/crates/ide_assists/src/handlers/remove_dbg.rs b/crates/ide_assists/src/handlers/remove_dbg.rs
index 2862cfa9c..c8226550f 100644
--- a/crates/ide_assists/src/handlers/remove_dbg.rs
+++ b/crates/ide_assists/src/handlers/remove_dbg.rs
@@ -30,7 +30,7 @@ pub(crate) fn remove_dbg(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
         if new_contents.is_empty() {
             match_ast! {
                 match it {
-                    ast::BlockExpr(it) => {
+                    ast::BlockExpr(_it) => {
                         macro_call.syntax()
                             .prev_sibling_or_token()
                             .and_then(whitespace_start)
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 3e2c82dac..3694f468f 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -28,7 +28,9 @@ pub use assist_config::AssistConfig;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum AssistKind {
+    // FIXME: does the None variant make sense? Probably not.
     None,
+
     QuickFix,
     Generate,
     Refactor,
diff --git a/crates/ide_completion/src/item.rs b/crates/ide_completion/src/item.rs
index cc4ac9ea2..16991b688 100644
--- a/crates/ide_completion/src/item.rs
+++ b/crates/ide_completion/src/item.rs
@@ -29,7 +29,7 @@ pub struct CompletionItem {
     /// Range of identifier that is being completed.
     ///
     /// It should be used primarily for UI, but we also use this to convert
-    /// genetic TextEdit into LSP's completion edit (see conv.rs).
+    /// generic TextEdit into LSP's completion edit (see conv.rs).
     ///
     /// `source_range` must contain the completion offset. `insert_text` should
     /// start with what `source_range` points to, or VSCode will filter out the
diff --git a/crates/project_model/src/build_data.rs b/crates/project_model/src/build_data.rs
index 0d4d39fef..ab5cc8c49 100644
--- a/crates/project_model/src/build_data.rs
+++ b/crates/project_model/src/build_data.rs
@@ -58,12 +58,17 @@ impl PartialEq for BuildDataConfig {
 
 impl Eq for BuildDataConfig {}
 
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct BuildDataCollector {
+    wrap_rustc: bool,
     configs: FxHashMap<AbsPathBuf, BuildDataConfig>,
 }
 
 impl BuildDataCollector {
+    pub fn new(wrap_rustc: bool) -> Self {
+        Self { wrap_rustc, configs: FxHashMap::default() }
+    }
+
     pub(crate) fn add_config(&mut self, workspace_root: &AbsPath, config: BuildDataConfig) {
         self.configs.insert(workspace_root.to_path_buf(), config);
     }
@@ -71,15 +76,14 @@ impl BuildDataCollector {
     pub fn collect(&mut self, progress: &dyn Fn(String)) -> Result<BuildDataResult> {
         let mut res = BuildDataResult::default();
         for (path, config) in self.configs.iter() {
-            res.per_workspace.insert(
-                path.clone(),
-                collect_from_workspace(
-                    &config.cargo_toml,
-                    &config.cargo_features,
-                    &config.packages,
-                    progress,
-                )?,
-            );
+            let workspace_build_data = WorkspaceBuildData::collect(
+                &config.cargo_toml,
+                &config.cargo_features,
+                &config.packages,
+                self.wrap_rustc,
+                progress,
+            )?;
+            res.per_workspace.insert(path.clone(), workspace_build_data);
         }
         Ok(res)
     }
@@ -120,119 +124,137 @@ impl BuildDataConfig {
     }
 }
 
-fn collect_from_workspace(
-    cargo_toml: &AbsPath,
-    cargo_features: &CargoConfig,
-    packages: &Vec<cargo_metadata::Package>,
-    progress: &dyn Fn(String),
-) -> Result<WorkspaceBuildData> {
-    let mut cmd = Command::new(toolchain::cargo());
-    cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
-        .arg(cargo_toml.as_ref());
-
-    // --all-targets includes tests, benches and examples in addition to the
-    // default lib and bins. This is an independent concept from the --targets
-    // flag below.
-    cmd.arg("--all-targets");
-
-    if let Some(target) = &cargo_features.target {
-        cmd.args(&["--target", target]);
-    }
+impl WorkspaceBuildData {
+    fn collect(
+        cargo_toml: &AbsPath,
+        cargo_features: &CargoConfig,
+        packages: &Vec<cargo_metadata::Package>,
+        wrap_rustc: bool,
+        progress: &dyn Fn(String),
+    ) -> Result<WorkspaceBuildData> {
+        let mut cmd = Command::new(toolchain::cargo());
+
+        if wrap_rustc {
+            // Setup RUSTC_WRAPPER to point to `rust-analyzer` binary itself. We use
+            // that to compile only proc macros and build scripts during the initial
+            // `cargo check`.
+            let myself = std::env::current_exe()?;
+            cmd.env("RUSTC_WRAPPER", myself);
+            cmd.env("RA_RUSTC_WRAPPER", "1");
+        }
+
+        cmd.args(&["check", "--workspace", "--message-format=json", "--manifest-path"])
+            .arg(cargo_toml.as_ref());
 
-    if cargo_features.all_features {
-        cmd.arg("--all-features");
-    } else {
-        if cargo_features.no_default_features {
-            // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
-            // https://github.com/oli-obk/cargo_metadata/issues/79
-            cmd.arg("--no-default-features");
+        // --all-targets includes tests, benches and examples in addition to the
+        // default lib and bins. This is an independent concept from the --targets
+        // flag below.
+        cmd.arg("--all-targets");
+
+        if let Some(target) = &cargo_features.target {
+            cmd.args(&["--target", target]);
         }
-        if !cargo_features.features.is_empty() {
-            cmd.arg("--features");
-            cmd.arg(cargo_features.features.join(" "));
+
+        if cargo_features.all_features {
+            cmd.arg("--all-features");
+        } else {
+            if cargo_features.no_default_features {
+                // FIXME: `NoDefaultFeatures` is mutual exclusive with `SomeFeatures`
+                // https://github.com/oli-obk/cargo_metadata/issues/79
+                cmd.arg("--no-default-features");
+            }
+            if !cargo_features.features.is_empty() {
+                cmd.arg("--features");
+                cmd.arg(cargo_features.features.join(" "));
+            }
         }
-    }
 
-    cmd.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());
-
-    let mut child = cmd.spawn().map(JodChild)?;
-    let child_stdout = child.stdout.take().unwrap();
-    let stdout = BufReader::new(child_stdout);
-
-    let mut res = WorkspaceBuildData::default();
-    for message in cargo_metadata::Message::parse_stream(stdout).flatten() {
-        match message {
-            Message::BuildScriptExecuted(BuildScript {
-                package_id, out_dir, cfgs, env, ..
-            }) => {
-                let cfgs = {
-                    let mut acc = Vec::new();
-                    for cfg in cfgs {
-                        match cfg.parse::<CfgFlag>() {
-                            Ok(it) => acc.push(it),
-                            Err(err) => {
-                                anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
-                            }
-                        };
+        cmd.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());
+
+        let mut child = cmd.spawn().map(JodChild)?;
+        let child_stdout = child.stdout.take().unwrap();
+        let stdout = BufReader::new(child_stdout);
+
+        let mut res = WorkspaceBuildData::default();
+        for message in cargo_metadata::Message::parse_stream(stdout).flatten() {
+            match message {
+                Message::BuildScriptExecuted(BuildScript {
+                    package_id,
+                    out_dir,
+                    cfgs,
+                    env,
+                    ..
+                }) => {
+                    let cfgs = {
+                        let mut acc = Vec::new();
+                        for cfg in cfgs {
+                            match cfg.parse::<CfgFlag>() {
+                                Ok(it) => acc.push(it),
+                                Err(err) => {
+                                    anyhow::bail!("invalid cfg from cargo-metadata: {}", err)
+                                }
+                            };
+                        }
+                        acc
+                    };
+                    let package_build_data =
+                        res.per_package.entry(package_id.repr.clone()).or_default();
+                    // cargo_metadata crate returns default (empty) path for
+                    // older cargos, which is not absolute, so work around that.
+                    if !out_dir.as_str().is_empty() {
+                        let out_dir = AbsPathBuf::assert(PathBuf::from(out_dir.into_os_string()));
+                        package_build_data.out_dir = Some(out_dir);
+                        package_build_data.cfgs = cfgs;
                     }
-                    acc
-                };
-                let package_build_data =
-                    res.per_package.entry(package_id.repr.clone()).or_default();
-                // cargo_metadata crate returns default (empty) path for
-                // older cargos, which is not absolute, so work around that.
-                if !out_dir.as_str().is_empty() {
-                    let out_dir = AbsPathBuf::assert(PathBuf::from(out_dir.into_os_string()));
-                    package_build_data.out_dir = Some(out_dir);
-                    package_build_data.cfgs = cfgs;
-                }
 
-                package_build_data.envs = env;
-            }
-            Message::CompilerArtifact(message) => {
-                progress(format!("metadata {}", message.target.name));
-
-                if message.target.kind.contains(&"proc-macro".to_string()) {
-                    let package_id = message.package_id;
-                    // Skip rmeta file
-                    if let Some(filename) = message.filenames.iter().find(|name| is_dylib(name)) {
-                        let filename = AbsPathBuf::assert(PathBuf::from(&filename));
-                        let package_build_data =
-                            res.per_package.entry(package_id.repr.clone()).or_default();
-                        package_build_data.proc_macro_dylib_path = Some(filename);
+                    package_build_data.envs = env;
+                }
+                Message::CompilerArtifact(message) => {
+                    progress(format!("metadata {}", message.target.name));
+
+                    if message.target.kind.contains(&"proc-macro".to_string()) {
+                        let package_id = message.package_id;
+                        // Skip rmeta file
+                        if let Some(filename) = message.filenames.iter().find(|name| is_dylib(name))
+                        {
+                            let filename = AbsPathBuf::assert(PathBuf::from(&filename));
+                            let package_build_data =
+                                res.per_package.entry(package_id.repr.clone()).or_default();
+                            package_build_data.proc_macro_dylib_path = Some(filename);
+                        }
                     }
                 }
+                Message::CompilerMessage(message) => {
+                    progress(message.target.name.clone());
+                }
+                Message::BuildFinished(_) => {}
+                Message::TextLine(_) => {}
+                _ => {}
             }
-            Message::CompilerMessage(message) => {
-                progress(message.target.name.clone());
-            }
-            Message::BuildFinished(_) => {}
-            Message::TextLine(_) => {}
-            _ => {}
         }
-    }
 
-    for package in packages {
-        let package_build_data = res.per_package.entry(package.id.repr.clone()).or_default();
-        inject_cargo_env(package, package_build_data);
-        if let Some(out_dir) = &package_build_data.out_dir {
-            // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
-            if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
-                package_build_data.envs.push(("OUT_DIR".to_string(), out_dir));
+        for package in packages {
+            let package_build_data = res.per_package.entry(package.id.repr.clone()).or_default();
+            inject_cargo_env(package, package_build_data);
+            if let Some(out_dir) = &package_build_data.out_dir {
+                // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
+                if let Some(out_dir) = out_dir.to_str().map(|s| s.to_owned()) {
+                    package_build_data.envs.push(("OUT_DIR".to_string(), out_dir));
+                }
             }
         }
-    }
 
-    let output = child.into_inner().wait_with_output()?;
-    if !output.status.success() {
-        let mut stderr = String::from_utf8(output.stderr).unwrap_or_default();
-        if stderr.is_empty() {
-            stderr = "cargo check failed".to_string();
+        let output = child.into_inner().wait_with_output()?;
+        if !output.status.success() {
+            let mut stderr = String::from_utf8(output.stderr).unwrap_or_default();
+            if stderr.is_empty() {
+                stderr = "cargo check failed".to_string();
+            }
+            res.error = Some(stderr)
         }
-        res.error = Some(stderr)
-    }
 
-    Ok(res)
+        Ok(res)
+    }
 }
 
 // FIXME: File a better way to know if it is a dylib
diff --git a/crates/rust-analyzer/build.rs b/crates/rust-analyzer/build.rs
index 999dc5928..13b903891 100644
--- a/crates/rust-analyzer/build.rs
+++ b/crates/rust-analyzer/build.rs
@@ -39,7 +39,8 @@ fn set_rerun() {
 }
 
 fn rev() -> Option<String> {
-    let output = Command::new("git").args(&["describe", "--tags"]).output().ok()?;
+    let output =
+        Command::new("git").args(&["describe", "--tags", "--exclude", "nightly"]).output().ok()?;
     let stdout = String::from_utf8(output.stdout).ok()?;
     Some(stdout)
 }
diff --git a/crates/rust-analyzer/src/benchmarks.rs b/crates/rust-analyzer/src/benchmarks.rs
index bf569b40b..bdd94b1c4 100644
--- a/crates/rust-analyzer/src/benchmarks.rs
+++ b/crates/rust-analyzer/src/benchmarks.rs
@@ -30,8 +30,11 @@ fn benchmark_integrated_highlighting() {
     let file = "./crates/ide_db/src/apply_change.rs";
 
     let cargo_config = Default::default();
-    let load_cargo_config =
-        LoadCargoConfig { load_out_dirs_from_check: true, with_proc_macro: false };
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check: true,
+        wrap_rustc: false,
+        with_proc_macro: false,
+    };
 
     let (mut host, vfs, _proc_macro) = {
         let _it = stdx::timeit("workspace loading");
diff --git a/crates/rust-analyzer/src/bin/main.rs b/crates/rust-analyzer/src/bin/main.rs
index 873e82c7b..f0abb5b15 100644
--- a/crates/rust-analyzer/src/bin/main.rs
+++ b/crates/rust-analyzer/src/bin/main.rs
@@ -3,6 +3,7 @@
 //! Based on cli flags, either spawns an LSP server, or runs a batch analysis
 mod flags;
 mod logger;
+mod rustc_wrapper;
 
 use std::{convert::TryFrom, env, fs, path::Path, process};
 
@@ -26,6 +27,20 @@ static ALLOC: mimalloc::MiMalloc = mimalloc::MiMalloc;
 static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;
 
 fn main() {
+    if std::env::var("RA_RUSTC_WRAPPER").is_ok() {
+        let mut args = std::env::args_os();
+        let _me = args.next().unwrap();
+        let rustc = args.next().unwrap();
+        let code = match rustc_wrapper::run_rustc_skipping_cargo_checking(rustc, args.collect()) {
+            Ok(rustc_wrapper::ExitCode(code)) => code.unwrap_or(102),
+            Err(err) => {
+                eprintln!("{}", err);
+                101
+            }
+        };
+        process::exit(code);
+    }
+
     if let Err(err) = try_main() {
         log::error!("Unexpected error: {}", err);
         eprintln!("{}", err);
diff --git a/crates/rust-analyzer/src/bin/rustc_wrapper.rs b/crates/rust-analyzer/src/bin/rustc_wrapper.rs
new file mode 100644
index 000000000..2f6d4706d
--- /dev/null
+++ b/crates/rust-analyzer/src/bin/rustc_wrapper.rs
@@ -0,0 +1,46 @@
+//! We setup RUSTC_WRAPPER to point to `rust-analyzer` binary itself during the
+//! initial `cargo check`. That way, we avoid checking the actual project, and
+//! only build proc macros and build.rs.
+//!
+//! Code taken from IntelliJ :0)
+//!     https://github.com/intellij-rust/intellij-rust/blob/master/native-helper/src/main.rs
+use std::{
+    ffi::OsString,
+    io,
+    process::{Command, Stdio},
+};
+
+/// ExitCode/ExitStatus are impossible to create :(.
+pub(crate) struct ExitCode(pub(crate) Option<i32>);
+
+pub(crate) fn run_rustc_skipping_cargo_checking(
+    rustc_executable: OsString,
+    args: Vec<OsString>,
+) -> io::Result<ExitCode> {
+    let is_cargo_check = args.iter().any(|arg| {
+        let arg = arg.to_string_lossy();
+        // `cargo check` invokes `rustc` with `--emit=metadata` argument.
+        //
+        // https://doc.rust-lang.org/rustc/command-line-arguments.html#--emit-specifies-the-types-of-output-files-to-generate
+        // link —     Generates the crates specified by --crate-type. The default
+        //            output filenames depend on the crate type and platform. This
+        //            is the default if --emit is not specified.
+        // metadata — Generates a file containing metadata about the crate.
+        //            The default output filename is CRATE_NAME.rmeta.
+        arg.starts_with("--emit=") && arg.contains("metadata") && !arg.contains("link")
+    });
+    if is_cargo_check {
+        return Ok(ExitCode(Some(0)));
+    }
+    run_rustc(rustc_executable, args)
+}
+
+fn run_rustc(rustc_executable: OsString, args: Vec<OsString>) -> io::Result<ExitCode> {
+    let mut child = Command::new(rustc_executable)
+        .args(args)
+        .stdin(Stdio::inherit())
+        .stdout(Stdio::inherit())
+        .stderr(Stdio::inherit())
+        .spawn()?;
+    Ok(ExitCode(child.wait()?.code()))
+}
diff --git a/crates/rust-analyzer/src/cli/analysis_stats.rs b/crates/rust-analyzer/src/cli/analysis_stats.rs
index fe9f273b0..3f3134562 100644
--- a/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -68,6 +68,7 @@ impl AnalysisStatsCmd {
         cargo_config.no_sysroot = self.no_sysroot;
         let load_cargo_config = LoadCargoConfig {
             load_out_dirs_from_check: self.load_output_dirs,
+            wrap_rustc: false,
             with_proc_macro: self.with_proc_macro,
         };
         let (host, vfs, _proc_macro) =
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
index 8b985716b..74f784338 100644
--- a/crates/rust-analyzer/src/cli/diagnostics.rs
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -34,7 +34,8 @@ pub fn diagnostics(
     with_proc_macro: bool,
 ) -> Result<()> {
     let cargo_config = Default::default();
-    let load_cargo_config = LoadCargoConfig { load_out_dirs_from_check, with_proc_macro };
+    let load_cargo_config =
+        LoadCargoConfig { load_out_dirs_from_check, with_proc_macro, wrap_rustc: false };
     let (host, _vfs, _proc_macro) =
         load_workspace_at(path, &cargo_config, &load_cargo_config, &|_| {})?;
     let db = host.raw_database();
@@ -56,7 +57,8 @@ pub fn diagnostics(
             let crate_name =
                 module.krate().display_name(db).as_deref().unwrap_or("unknown").to_string();
             println!("processing crate: {}, module: {}", crate_name, _vfs.file_path(file_id));
-            for diagnostic in analysis.diagnostics(&DiagnosticsConfig::default(), file_id).unwrap()
+            for diagnostic in
+                analysis.diagnostics(&DiagnosticsConfig::default(), false, file_id).unwrap()
             {
                 if matches!(diagnostic.severity, Severity::Error) {
                     found_error = true;
diff --git a/crates/rust-analyzer/src/cli/load_cargo.rs b/crates/rust-analyzer/src/cli/load_cargo.rs
index 310c36904..75bad1112 100644
--- a/crates/rust-analyzer/src/cli/load_cargo.rs
+++ b/crates/rust-analyzer/src/cli/load_cargo.rs
@@ -15,6 +15,7 @@ use crate::reload::{ProjectFolders, SourceRootConfig};
 
 pub struct LoadCargoConfig {
     pub load_out_dirs_from_check: bool,
+    pub wrap_rustc: bool,
     pub with_proc_macro: bool,
 }
 
@@ -52,7 +53,7 @@ pub fn load_workspace(
     };
 
     let build_data = if config.load_out_dirs_from_check {
-        let mut collector = BuildDataCollector::default();
+        let mut collector = BuildDataCollector::new(config.wrap_rustc);
         ws.collect_build_data_configs(&mut collector);
         Some(collector.collect(progress)?)
     } else {
@@ -136,8 +137,11 @@ mod tests {
     fn test_loading_rust_analyzer() -> Result<()> {
         let path = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap().parent().unwrap();
         let cargo_config = Default::default();
-        let load_cargo_config =
-            LoadCargoConfig { load_out_dirs_from_check: false, with_proc_macro: false };
+        let load_cargo_config = LoadCargoConfig {
+            load_out_dirs_from_check: false,
+            wrap_rustc: false,
+            with_proc_macro: false,
+        };
         let (host, _vfs, _proc_macro) =
             load_workspace_at(path, &cargo_config, &load_cargo_config, &|_| {})?;
 
diff --git a/crates/rust-analyzer/src/cli/ssr.rs b/crates/rust-analyzer/src/cli/ssr.rs
index 79f426fff..1fd9b5a9b 100644
--- a/crates/rust-analyzer/src/cli/ssr.rs
+++ b/crates/rust-analyzer/src/cli/ssr.rs
@@ -9,8 +9,11 @@ use ide_ssr::{MatchFinder, SsrPattern, SsrRule};
 pub fn apply_ssr_rules(rules: Vec<SsrRule>) -> Result<()> {
     use ide_db::base_db::SourceDatabaseExt;
     let cargo_config = Default::default();
-    let load_cargo_config =
-        LoadCargoConfig { load_out_dirs_from_check: true, with_proc_macro: true };
+    let load_cargo_config = LoadCargoConfig {
+        load_out_dirs_from_check: true,
+        wrap_rustc: false,
+        with_proc_macro: true,
+    };
     let (host, vfs, _proc_macro) =
         load_workspace_at(&std::env::current_dir()?, &cargo_config, &load_cargo_config, &|_| {})?;
     let db = host.raw_database();
@@ -37,7 +40,7 @@ pub fn search_for_patterns(patterns: Vec<SsrPattern>, debug_snippet: Option<Stri
     use ide_db::symbol_index::SymbolsDatabase;
     let cargo_config = Default::default();
     let load_cargo_config =
-        LoadCargoConfig { load_out_dirs_from_check: true, with_proc_macro: true };
+        LoadCargoConfig { load_out_dirs_from_check: true, wrap_rustc: true, with_proc_macro: true };
     let (host, _vfs, _proc_macro) =
         load_workspace_at(&std::env::current_dir()?, &cargo_config, &load_cargo_config, &|_| {})?;
     let db = host.raw_database();
diff --git a/crates/rust-analyzer/src/config.rs b/crates/rust-analyzer/src/config.rs
index e012b4452..1edaa394a 100644
--- a/crates/rust-analyzer/src/config.rs
+++ b/crates/rust-analyzer/src/config.rs
@@ -48,6 +48,9 @@ config_data! {
         /// Run build scripts (`build.rs`) for more precise code analysis.
         cargo_runBuildScripts |
         cargo_loadOutDirsFromCheck: bool = "true",
+        /// Use `RUSTC_WRAPPER=rust-analyzer` when running build scripts to
+        /// avoid compiling unnecessary things.
+        cargo_useRustcWrapperForBuildScripts: bool = "true",
         /// Do not activate the `default` feature.
         cargo_noDefaultFeatures: bool    = "false",
         /// Compilation target (target triple).
@@ -493,6 +496,9 @@ impl Config {
     pub fn run_build_scripts(&self) -> bool {
         self.data.cargo_runBuildScripts || self.data.procMacro_enable
     }
+    pub fn wrap_rustc(&self) -> bool {
+        self.data.cargo_useRustcWrapperForBuildScripts
+    }
     pub fn cargo(&self) -> CargoConfig {
         let rustc_source = self.data.rustcSource.as_ref().map(|rustc_src| {
             if rustc_src == "discover" {
@@ -656,6 +662,19 @@ impl Config {
     pub fn code_lens_refresh(&self) -> bool {
         try_or!(self.caps.workspace.as_ref()?.code_lens.as_ref()?.refresh_support?, false)
     }
+    pub fn insert_replace_support(&self) -> bool {
+        try_or!(
+            self.caps
+                .text_document
+                .as_ref()?
+                .completion
+                .as_ref()?
+                .completion_item
+                .as_ref()?
+                .insert_replace_support?,
+            false
+        )
+    }
 }
 
 #[derive(Deserialize, Debug, Clone)]
diff --git a/crates/rust-analyzer/src/from_proto.rs b/crates/rust-analyzer/src/from_proto.rs
index 5b02b2598..712d5a9c2 100644
--- a/crates/rust-analyzer/src/from_proto.rs
+++ b/crates/rust-analyzer/src/from_proto.rs
@@ -42,27 +42,27 @@ pub(crate) fn text_range(line_index: &LineIndex, range: lsp_types::Range) -> Tex
     TextRange::new(start, end)
 }
 
-pub(crate) fn file_id(world: &GlobalStateSnapshot, url: &lsp_types::Url) -> Result<FileId> {
-    world.url_to_file_id(url)
+pub(crate) fn file_id(snap: &GlobalStateSnapshot, url: &lsp_types::Url) -> Result<FileId> {
+    snap.url_to_file_id(url)
 }
 
 pub(crate) fn file_position(
-    world: &GlobalStateSnapshot,
+    snap: &GlobalStateSnapshot,
     tdpp: lsp_types::TextDocumentPositionParams,
 ) -> Result<FilePosition> {
-    let file_id = file_id(world, &tdpp.text_document.uri)?;
-    let line_index = world.file_line_index(file_id)?;
+    let file_id = file_id(snap, &tdpp.text_document.uri)?;
+    let line_index = snap.file_line_index(file_id)?;
     let offset = offset(&line_index, tdpp.position);
     Ok(FilePosition { file_id, offset })
 }
 
 pub(crate) fn file_range(
-    world: &GlobalStateSnapshot,
+    snap: &GlobalStateSnapshot,
     text_document_identifier: lsp_types::TextDocumentIdentifier,
     range: lsp_types::Range,
 ) -> Result<FileRange> {
-    let file_id = file_id(world, &text_document_identifier.uri)?;
-    let line_index = world.file_line_index(file_id)?;
+    let file_id = file_id(snap, &text_document_identifier.uri)?;
+    let line_index = snap.file_line_index(file_id)?;
     let range = text_range(&line_index, range);
     Ok(FileRange { file_id, range })
 }
@@ -82,7 +82,7 @@ pub(crate) fn assist_kind(kind: lsp_types::CodeActionKind) -> Option<AssistKind>
 }
 
 pub(crate) fn annotation(
-    world: &GlobalStateSnapshot,
+    snap: &GlobalStateSnapshot,
     code_lens: lsp_types::CodeLens,
 ) -> Result<Annotation> {
     let data = code_lens.data.unwrap();
@@ -91,25 +91,25 @@ pub(crate) fn annotation(
     match resolve {
         lsp_ext::CodeLensResolveData::Impls(params) => {
             let file_id =
-                world.url_to_file_id(&params.text_document_position_params.text_document.uri)?;
-            let line_index = world.file_line_index(file_id)?;
+                snap.url_to_file_id(&params.text_document_position_params.text_document.uri)?;
+            let line_index = snap.file_line_index(file_id)?;
 
             Ok(Annotation {
                 range: text_range(&line_index, code_lens.range),
                 kind: AnnotationKind::HasImpls {
-                    position: file_position(world, params.text_document_position_params)?,
+                    position: file_position(snap, params.text_document_position_params)?,
                     data: None,
                 },
             })
         }
         lsp_ext::CodeLensResolveData::References(params) => {
-            let file_id = world.url_to_file_id(&params.text_document.uri)?;
-            let line_index = world.file_line_index(file_id)?;
+            let file_id = snap.url_to_file_id(&params.text_document.uri)?;
+            let line_index = snap.file_line_index(file_id)?;
 
             Ok(Annotation {
                 range: text_range(&line_index, code_lens.range),
                 kind: AnnotationKind::HasReferences {
-                    position: file_position(world, params)?,
+                    position: file_position(snap, params)?,
                     data: None,
                 },
             })
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 31d8c487b..4f0c9d23c 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -17,7 +17,7 @@ use lsp_server::ErrorCode;
 use lsp_types::{
     CallHierarchyIncomingCall, CallHierarchyIncomingCallsParams, CallHierarchyItem,
     CallHierarchyOutgoingCall, CallHierarchyOutgoingCallsParams, CallHierarchyPrepareParams,
-    CodeActionKind, CodeLens, CompletionItem, Diagnostic, DiagnosticTag, DocumentFormattingParams,
+    CodeLens, CompletionItem, Diagnostic, DiagnosticTag, DocumentFormattingParams,
     DocumentHighlight, FoldingRange, FoldingRangeParams, HoverContents, Location, NumberOrString,
     Position, PrepareRenameResponse, Range, RenameParams, SemanticTokensDeltaParams,
     SemanticTokensFullDeltaResult, SemanticTokensParams, SemanticTokensRangeParams,
@@ -36,7 +36,7 @@ use crate::{
     diff::diff,
     from_proto,
     global_state::{GlobalState, GlobalStateSnapshot},
-    line_index::{LineEndings, LineIndex},
+    line_index::LineEndings,
     lsp_ext::{self, InlayHint, InlayHintsParams},
     lsp_utils::all_edits_are_disjoint,
     to_proto, LspError, Result,
@@ -664,10 +664,13 @@ pub(crate) fn handle_completion(
     };
     let line_index = snap.file_line_index(position.file_id)?;
 
+    let insert_replace_support =
+        snap.config.insert_replace_support().then(|| text_document_position.position);
     let items: Vec<CompletionItem> = items
         .into_iter()
         .flat_map(|item| {
-            let mut new_completion_items = to_proto::completion_item(&line_index, item.clone());
+            let mut new_completion_items =
+                to_proto::completion_item(insert_replace_support, &line_index, item.clone());
 
             if completion_config.enable_imports_on_the_fly {
                 for new_item in &mut new_completion_items {
@@ -979,84 +982,52 @@ pub(crate) fn handle_code_action(
     params: lsp_types::CodeActionParams,
 ) -> Result<Option<Vec<lsp_ext::CodeAction>>> {
     let _p = profile::span("handle_code_action");
-    // We intentionally don't support command-based actions, as those either
-    // requires custom client-code anyway, or requires server-initiated edits.
-    // Server initiated edits break causality, so we avoid those as well.
+
     if !snap.config.code_action_literals() {
+        // We intentionally don't support command-based actions, as those either
+        // require either custom client-code or server-initiated edits. Server
+        // initiated edits break causality, so we avoid those.
         return Ok(None);
     }
 
-    let file_id = from_proto::file_id(&snap, &params.text_document.uri)?;
-    let line_index = snap.file_line_index(file_id)?;
-    let range = from_proto::text_range(&line_index, params.range);
-    let frange = FileRange { file_id, range };
+    let line_index =
+        snap.file_line_index(from_proto::file_id(&snap, &params.text_document.uri)?)?;
+    let frange = from_proto::file_range(&snap, params.text_document.clone(), params.range)?;
 
     let mut assists_config = snap.config.assist();
     assists_config.allowed = params
-        .clone()
         .context
         .only
+        .clone()
         .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect());
 
     let mut res: Vec<lsp_ext::CodeAction> = Vec::new();
 
-    let include_quick_fixes = match &params.context.only {
-        Some(v) => v.iter().any(|it| {
-            it == &lsp_types::CodeActionKind::EMPTY || it == &lsp_types::CodeActionKind::QUICKFIX
-        }),
-        None => true,
-    };
-    if include_quick_fixes {
-        add_quick_fixes(&snap, frange, &line_index, &mut res)?;
-    }
-
-    if snap.config.code_action_resolve() {
-        for (index, assist) in
-            snap.analysis.assists(&assists_config, false, frange)?.into_iter().enumerate()
-        {
-            res.push(to_proto::unresolved_code_action(&snap, params.clone(), assist, index)?);
-        }
-    } else {
-        for assist in snap.analysis.assists(&assists_config, true, frange)?.into_iter() {
-            res.push(to_proto::resolved_code_action(&snap, assist)?);
-        }
-    }
-
-    Ok(Some(res))
-}
-
-fn add_quick_fixes(
-    snap: &GlobalStateSnapshot,
-    frange: FileRange,
-    line_index: &LineIndex,
-    acc: &mut Vec<lsp_ext::CodeAction>,
-) -> Result<()> {
-    let diagnostics = snap.analysis.diagnostics(&snap.config.diagnostics(), frange.file_id)?;
-
-    for fix in diagnostics
-        .into_iter()
-        .filter_map(|d| d.fix)
-        .filter(|fix| fix.fix_trigger_range.intersect(frange.range).is_some())
-    {
-        let edit = to_proto::snippet_workspace_edit(&snap, fix.source_change)?;
-        let action = lsp_ext::CodeAction {
-            title: fix.label.to_string(),
-            group: None,
-            kind: Some(CodeActionKind::QUICKFIX),
-            edit: Some(edit),
-            is_preferred: Some(false),
-            data: None,
-        };
-        acc.push(action);
+    let code_action_resolve_cap = snap.config.code_action_resolve();
+    let assists = snap.analysis.assists_with_fixes(
+        &assists_config,
+        &snap.config.diagnostics(),
+        !code_action_resolve_cap,
+        frange,
+    )?;
+    for (index, assist) in assists.into_iter().enumerate() {
+        let resolve_data =
+            if code_action_resolve_cap { Some((index, params.clone())) } else { None };
+        let code_action = to_proto::code_action(&snap, assist, resolve_data)?;
+        res.push(code_action)
     }
 
+    // Fixes from `cargo check`.
     for fix in snap.check_fixes.get(&frange.file_id).into_iter().flatten() {
+        // FIXME: this mapping is awkward and shouldn't exist. Refactor
+        // `snap.check_fixes` to not convert to LSP prematurely.
         let fix_range = from_proto::text_range(&line_index, fix.range);
         if fix_range.intersect(frange.range).is_some() {
-            acc.push(fix.action.clone());
+            res.push(fix.action.clone());
         }
     }
-    Ok(())
+
+    Ok(Some(res))
 }
 
 pub(crate) fn handle_code_action_resolve(
@@ -1081,12 +1052,18 @@ pub(crate) fn handle_code_action_resolve(
         .only
         .map(|it| it.into_iter().filter_map(from_proto::assist_kind).collect());
 
-    let assists = snap.analysis.assists(&assists_config, true, frange)?;
+    let assists = snap.analysis.assists_with_fixes(
+        &assists_config,
+        &snap.config.diagnostics(),
+        true,
+        frange,
+    )?;
+
     let (id, index) = split_once(&params.id, ':').unwrap();
     let index = index.parse::<usize>().unwrap();
     let assist = &assists[index];
     assert!(assist.id.0 == id);
-    let edit = to_proto::resolved_code_action(&snap, assist.clone())?.edit;
+    let edit = to_proto::code_action(&snap, assist.clone(), None)?.edit;
     code_action.edit = edit;
     Ok(code_action)
 }
@@ -1205,7 +1182,7 @@ pub(crate) fn publish_diagnostics(
 
     let diagnostics: Vec<Diagnostic> = snap
         .analysis
-        .diagnostics(&snap.config.diagnostics(), file_id)?
+        .diagnostics(&snap.config.diagnostics(), false, file_id)?
         .into_iter()
         .map(|d| Diagnostic {
             range: to_proto::range(&line_index, d.range),
diff --git a/crates/rust-analyzer/src/lsp_utils.rs b/crates/rust-analyzer/src/lsp_utils.rs
index 2ac487632..73c4193e8 100644
--- a/crates/rust-analyzer/src/lsp_utils.rs
+++ b/crates/rust-analyzer/src/lsp_utils.rs
@@ -150,8 +150,16 @@ pub(crate) fn all_edits_are_disjoint(
             edit_ranges.push(edit.range);
         }
         Some(lsp_types::CompletionTextEdit::InsertAndReplace(edit)) => {
-            edit_ranges.push(edit.insert);
-            edit_ranges.push(edit.replace);
+            let replace = edit.replace;
+            let insert = edit.insert;
+            if replace.start != insert.start
+                || insert.start > insert.end
+                || insert.end > replace.end
+            {
+                // insert has to be a prefix of replace but it is not
+                return false;
+            }
+            edit_ranges.push(replace);
         }
         None => {}
     }
@@ -314,18 +322,6 @@ mod tests {
             Some(CompletionTextEdit::InsertAndReplace(InsertReplaceEdit {
                 new_text: "new_text".to_string(),
                 insert: disjoint_edit.range,
-                replace: joint_edit.range,
-            }));
-        completion_with_joint_edits.additional_text_edits = None;
-        assert!(
-            !all_edits_are_disjoint(&completion_with_joint_edits, &[]),
-            "Completion with disjoint edits fails the validation even with empty extra edits"
-        );
-
-        completion_with_joint_edits.text_edit =
-            Some(CompletionTextEdit::InsertAndReplace(InsertReplaceEdit {
-                new_text: "new_text".to_string(),
-                insert: disjoint_edit.range,
                 replace: disjoint_edit_2.range,
             }));
         completion_with_joint_edits.additional_text_edits = Some(vec![joint_edit]);
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index 47c6c6d77..b3d4c6ec5 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -236,7 +236,8 @@ impl GlobalState {
                                     let workspaces_updated = !Arc::ptr_eq(&old, &self.workspaces);
 
                                     if self.config.run_build_scripts() && workspaces_updated {
-                                        let mut collector = BuildDataCollector::default();
+                                        let mut collector =
+                                            BuildDataCollector::new(self.config.wrap_rustc());
                                         for ws in self.workspaces.iter() {
                                             ws.collect_build_data_configs(&mut collector);
                                         }
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index d0cc1b61a..e51532d88 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -100,10 +100,6 @@ impl GlobalState {
         }
     }
     pub(crate) fn report_new_status_if_needed(&mut self) {
-        if !self.config.server_status_notification() {
-            return;
-        }
-
         let mut status = lsp_ext::ServerStatusParams {
             health: lsp_ext::Health::Ok,
             quiescent: self.is_quiescent(),
@@ -129,7 +125,14 @@ impl GlobalState {
 
         if self.last_reported_status.as_ref() != Some(&status) {
             self.last_reported_status = Some(status.clone());
-            self.send_notification::<lsp_ext::ServerStatusNotification>(status);
+
+            if let (lsp_ext::Health::Error, Some(message)) = (status.health, &status.message) {
+                self.show_message(lsp_types::MessageType::Error, message.clone());
+            }
+
+            if self.config.server_status_notification() {
+                self.send_notification::<lsp_ext::ServerStatusNotification>(status);
+            }
         }
     }
 
@@ -225,7 +228,6 @@ impl GlobalState {
 
         if let Some(error_message) = self.fetch_workspace_error() {
             log::error!("failed to switch workspaces: {}", error_message);
-            self.show_message(lsp_types::MessageType::Error, error_message);
             if !self.workspaces.is_empty() {
                 return;
             }
@@ -233,7 +235,6 @@ impl GlobalState {
 
         if let Some(error_message) = self.build_data_error() {
             log::error!("failed to switch build data: {}", error_message);
-            self.show_message(lsp_types::MessageType::Error, error_message);
         }
 
         let workspaces = self
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index df9292f8e..8d7cb9b74 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -145,6 +145,23 @@ pub(crate) fn text_edit(line_index: &LineIndex, indel: Indel) -> lsp_types::Text
     lsp_types::TextEdit { range, new_text }
 }
 
+pub(crate) fn completion_text_edit(
+    line_index: &LineIndex,
+    insert_replace_support: Option<lsp_types::Position>,
+    indel: Indel,
+) -> lsp_types::CompletionTextEdit {
+    let text_edit = text_edit(line_index, indel);
+    match insert_replace_support {
+        Some(cursor_pos) => lsp_types::InsertReplaceEdit {
+            new_text: text_edit.new_text,
+            insert: lsp_types::Range { start: text_edit.range.start, end: cursor_pos },
+            replace: text_edit.range,
+        }
+        .into(),
+        None => text_edit.into(),
+    }
+}
+
 pub(crate) fn snippet_text_edit(
     line_index: &LineIndex,
     is_snippet: bool,
@@ -179,6 +196,7 @@ pub(crate) fn snippet_text_edit_vec(
 }
 
 pub(crate) fn completion_item(
+    insert_replace_support: Option<lsp_types::Position>,
     line_index: &LineIndex,
     item: CompletionItem,
 ) -> Vec<lsp_types::CompletionItem> {
@@ -190,7 +208,7 @@ pub(crate) fn completion_item(
     for indel in item.text_edit().iter() {
         if indel.delete.contains_range(source_range) {
             text_edit = Some(if indel.delete == source_range {
-                self::text_edit(line_index, indel.clone())
+                self::completion_text_edit(line_index, insert_replace_support, indel.clone())
             } else {
                 assert!(source_range.end() == indel.delete.end());
                 let range1 = TextRange::new(indel.delete.start(), source_range.start());
@@ -198,7 +216,7 @@ pub(crate) fn completion_item(
                 let indel1 = Indel::replace(range1, String::new());
                 let indel2 = Indel::replace(range2, indel.insert.clone());
                 additional_text_edits.push(self::text_edit(line_index, indel1));
-                self::text_edit(line_index, indel2)
+                self::completion_text_edit(line_index, insert_replace_support, indel2)
             })
         } else {
             assert!(source_range.intersect(indel.delete).is_none());
@@ -213,7 +231,7 @@ pub(crate) fn completion_item(
         detail: item.detail().map(|it| it.to_string()),
         filter_text: Some(item.lookup().to_string()),
         kind: item.kind().map(completion_item_kind),
-        text_edit: Some(text_edit.into()),
+        text_edit: Some(text_edit),
         additional_text_edits: Some(additional_text_edits),
         documentation: item.documentation().map(documentation),
         deprecated: Some(item.deprecated()),
@@ -831,40 +849,31 @@ pub(crate) fn code_action_kind(kind: AssistKind) -> lsp_types::CodeActionKind {
     }
 }
 
-pub(crate) fn unresolved_code_action(
+pub(crate) fn code_action(
     snap: &GlobalStateSnapshot,
-    code_action_params: lsp_types::CodeActionParams,
     assist: Assist,
-    index: usize,
+    resolve_data: Option<(usize, lsp_types::CodeActionParams)>,
 ) -> Result<lsp_ext::CodeAction> {
-    assert!(assist.source_change.is_none());
-    let res = lsp_ext::CodeAction {
+    let mut res = lsp_ext::CodeAction {
         title: assist.label.to_string(),
         group: assist.group.filter(|_| snap.config.code_action_group()).map(|gr| gr.0),
         kind: Some(code_action_kind(assist.id.1)),
         edit: None,
         is_preferred: None,
-        data: Some(lsp_ext::CodeActionData {
-            id: format!("{}:{}", assist.id.0, index.to_string()),
-            code_action_params,
-        }),
-    };
-    Ok(res)
-}
-
-pub(crate) fn resolved_code_action(
-    snap: &GlobalStateSnapshot,
-    assist: Assist,
-) -> Result<lsp_ext::CodeAction> {
-    let change = assist.source_change.unwrap();
-    let res = lsp_ext::CodeAction {
-        edit: Some(snippet_workspace_edit(snap, change)?),
-        title: assist.label.to_string(),
-        group: assist.group.filter(|_| snap.config.code_action_group()).map(|gr| gr.0),
-        kind: Some(code_action_kind(assist.id.1)),
-        is_preferred: None,
         data: None,
     };
+    match (assist.source_change, resolve_data) {
+        (Some(it), _) => res.edit = Some(snippet_workspace_edit(snap, it)?),
+        (None, Some((index, code_action_params))) => {
+            res.data = Some(lsp_ext::CodeActionData {
+                id: format!("{}:{}", assist.id.0, index.to_string()),
+                code_action_params,
+            });
+        }
+        (None, None) => {
+            stdx::never!("assist should always be resolved if client can't do lazy resolving")
+        }
+    };
     Ok(res)
 }
 
@@ -1142,7 +1151,7 @@ mod tests {
             .unwrap()
             .into_iter()
             .filter(|c| c.label().ends_with("arg"))
-            .map(|c| completion_item(&line_index, c))
+            .map(|c| completion_item(None, &line_index, c))
             .flat_map(|comps| comps.into_iter().map(|c| (c.label, c.sort_text)))
             .collect();
         expect_test::expect![[r#"
diff --git a/crates/rust-analyzer/tests/rust-analyzer/main.rs b/crates/rust-analyzer/tests/rust-analyzer/main.rs
index 4442cbff6..52a2674d5 100644
--- a/crates/rust-analyzer/tests/rust-analyzer/main.rs
+++ b/crates/rust-analyzer/tests/rust-analyzer/main.rs
@@ -340,7 +340,6 @@ fn main() {}
                 }
               ]
             },
-            "isPreferred": false,
             "kind": "quickfix",
             "title": "Create module"
         }]),
@@ -411,7 +410,6 @@ fn main() {{}}
                 }
               ]
             },
-            "isPreferred": false,
             "kind": "quickfix",
             "title": "Create module"
         }]),
@@ -527,7 +525,7 @@ version = \"0.0.0\"
 #[test]
 fn out_dirs_check() {
     if skip_slow_tests() {
-        return;
+        // return;
     }
 
     let server = Project::with_fixture(
diff --git a/crates/rust-analyzer/tests/rust-analyzer/support.rs b/crates/rust-analyzer/tests/rust-analyzer/support.rs
index 8d68f1b7d..75e677762 100644
--- a/crates/rust-analyzer/tests/rust-analyzer/support.rs
+++ b/crates/rust-analyzer/tests/rust-analyzer/support.rs
@@ -32,8 +32,12 @@ impl<'a> Project<'a> {
             tmp_dir: None,
             roots: vec![],
             config: serde_json::json!({
-                // Loading standard library is costly, let's ignore it by default
-                "cargo": { "noSysroot": true }
+                "cargo": {
+                    // Loading standard library is costly, let's ignore it by default
+                    "noSysroot": true,
+                    // Can't use test binary as rustc wrapper.
+                    "useRustcWrapperForBuildScripts": false,
+                }
             }),
         }
     }
@@ -49,7 +53,17 @@ impl<'a> Project<'a> {
     }
 
     pub(crate) fn with_config(mut self, config: serde_json::Value) -> Project<'a> {
-        self.config = config;
+        fn merge(dst: &mut serde_json::Value, src: serde_json::Value) {
+            match (dst, src) {
+                (Value::Object(dst), Value::Object(src)) => {
+                    for (k, v) in src {
+                        merge(dst.entry(k).or_insert(v.clone()), v)
+                    }
+                }
+                (dst, src) => *dst = src,
+            }
+        }
+        merge(&mut self.config, config);
         self
     }
 
@@ -154,6 +168,7 @@ impl Server {
         self.send_notification(r)
     }
 
+    #[track_caller]
     pub(crate) fn request<R>(&self, params: R::Params, expected_resp: Value)
     where
         R: lsp_types::request::Request,
diff --git a/crates/test_utils/src/assert_linear.rs b/crates/test_utils/src/assert_linear.rs
new file mode 100644
index 000000000..6ecc232e1
--- /dev/null
+++ b/crates/test_utils/src/assert_linear.rs
@@ -0,0 +1,112 @@
+//! Checks that a set of measurements looks like a linear function rather than
+//! like a quadratic function. Algorithm:
+//!
+//! 1. Linearly scale input to be in [0; 1)
+//! 2. Using linear regression, compute the best linear function approximating
+//!    the input.
+//! 3. Compute RMSE and  maximal absolute error.
+//! 4. Check that errors are within tolerances and that the constant term is not
+//!    too negative.
+//!
+//! Ideally, we should use a proper "model selection" to directly compare
+//! quadratic and linear models, but that sounds rather complicated:
+//!
+//!     https://stats.stackexchange.com/questions/21844/selecting-best-model-based-on-linear-quadratic-and-cubic-fit-of-data
+//!
+//! We might get false positives on a VM, but never false negatives. So, if the
+//! first round fails, we repeat the ordeal three more times and fail only if
+//! every time there's a fault.
+use stdx::format_to;
+
+#[derive(Default)]
+pub struct AssertLinear {
+    rounds: Vec<Round>,
+}
+
+#[derive(Default)]
+struct Round {
+    samples: Vec<(f64, f64)>,
+    plot: String,
+    linear: bool,
+}
+
+impl AssertLinear {
+    pub fn next_round(&mut self) -> bool {
+        if let Some(round) = self.rounds.last_mut() {
+            round.finish();
+        }
+        if self.rounds.iter().any(|it| it.linear) || self.rounds.len() == 4 {
+            return false;
+        }
+        self.rounds.push(Round::default());
+        true
+    }
+
+    pub fn sample(&mut self, x: f64, y: f64) {
+        self.rounds.last_mut().unwrap().samples.push((x, y))
+    }
+}
+
+impl Drop for AssertLinear {
+    fn drop(&mut self) {
+        assert!(!self.rounds.is_empty());
+        if self.rounds.iter().all(|it| !it.linear) {
+            for round in &self.rounds {
+                eprintln!("\n{}", round.plot);
+            }
+            panic!("Doesn't look linear!")
+        }
+    }
+}
+
+impl Round {
+    fn finish(&mut self) {
+        let (mut xs, mut ys): (Vec<_>, Vec<_>) = self.samples.iter().copied().unzip();
+        normalize(&mut xs);
+        normalize(&mut ys);
+        let xy = xs.iter().copied().zip(ys.iter().copied());
+
+        // Linear regression: finding a and b to fit y = a + b*x.
+
+        let mean_x = mean(&xs);
+        let mean_y = mean(&ys);
+
+        let b = {
+            let mut num = 0.0;
+            let mut denom = 0.0;
+            for (x, y) in xy.clone() {
+                num += (x - mean_x) * (y - mean_y);
+                denom += (x - mean_x).powi(2);
+            }
+            num / denom
+        };
+
+        let a = mean_y - b * mean_x;
+
+        self.plot = format!("y_pred = {:.3} + {:.3} * x\n\nx     y     y_pred\n", a, b);
+
+        let mut se = 0.0;
+        let mut max_error = 0.0f64;
+        for (x, y) in xy {
+            let y_pred = a + b * x;
+            se += (y - y_pred).powi(2);
+            max_error = max_error.max((y_pred - y).abs());
+
+            format_to!(self.plot, "{:.3} {:.3} {:.3}\n", x, y, y_pred);
+        }
+
+        let rmse = (se / xs.len() as f64).sqrt();
+        format_to!(self.plot, "\nrmse = {:.3} max error = {:.3}", rmse, max_error);
+
+        self.linear = rmse < 0.05 && max_error < 0.1 && a > -0.1;
+
+        fn normalize(xs: &mut Vec<f64>) {
+            let max = xs.iter().copied().max_by(|a, b| a.partial_cmp(b).unwrap()).unwrap();
+            xs.iter_mut().for_each(|it| *it /= max);
+        }
+
+        fn mean(xs: &[f64]) -> f64 {
+            xs.iter().copied().sum::<f64>() / (xs.len() as f64)
+        }
+    }
+}
diff --git a/crates/test_utils/src/bench_fixture.rs b/crates/test_utils/src/bench_fixture.rs
index 3a37c4473..979156263 100644
--- a/crates/test_utils/src/bench_fixture.rs
+++ b/crates/test_utils/src/bench_fixture.rs
@@ -8,7 +8,10 @@ use crate::project_root;
 
 pub fn big_struct() -> String {
     let n = 1_000;
+    big_struct_n(n)
+}
 
+pub fn big_struct_n(n: u32) -> String {
     let mut buf = "pub struct RegisterBlock {".to_string();
     for i in 0..n {
         format_to!(buf, "  /// Doc comment for {}.\n", i);
diff --git a/crates/test_utils/src/lib.rs b/crates/test_utils/src/lib.rs
index c5f859790..72466c957 100644
--- a/crates/test_utils/src/lib.rs
+++ b/crates/test_utils/src/lib.rs
@@ -8,6 +8,7 @@
 
 pub mod bench_fixture;
 mod fixture;
+mod assert_linear;
 
 use std::{
     convert::{TryFrom, TryInto},
@@ -22,7 +23,7 @@ use text_size::{TextRange, TextSize};
 pub use dissimilar::diff as __diff;
 pub use rustc_hash::FxHashMap;
 
-pub use crate::fixture::Fixture;
+pub use crate::{assert_linear::AssertLinear, fixture::Fixture};
 
 pub const CURSOR_MARKER: &str = "$0";
 pub const ESCAPED_CURSOR_MARKER: &str = "\\$0";