111 files changed, 4733 insertions, 4169 deletions
diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index 8d4641355..04e2be390 100644
--- a/crates/base_db/src/fixture.rs
+++ b/crates/base_db/src/fixture.rs
@@ -1,62 +1,4 @@
-//! Fixtures are strings containing rust source code with optional metadata.
+//! A set of high-level utility fixture methods to use in tests.
-//! A fixture without metadata is parsed into a single source file.
-//! Use this to test functionality local to one file.
-//!
-//! Simple Example:
-//! ```
-//! r#"
-//! fn main() {
-//!     println!("Hello World")
-//! }
-//! "#
-//! ```
-//!
-//! Metadata can be added to a fixture after a `//-` comment.
-//! The basic form is specifying filenames,
-//! which is also how to define multiple files in a single test fixture
-//!
-//! Example using two files in the same crate:
-//! ```
-//! "
-//! //- /main.rs
-//! mod foo;
-//! fn main() {
-//!     foo::bar();
-//! }
-//!
-//! //- /foo.rs
-//! pub fn bar() {}
-//! "
-//! ```
-//!
-//! Example using two crates with one file each, with one crate depending on the other:
-//! ```
-//! r#"
-//! //- /main.rs crate:a deps:b
-//! fn main() {
-//!     b::foo();
-//! }
-//! //- /lib.rs crate:b
-//! pub fn b() {
-//!     println!("Hello World")
-//! }
-//! "#
-//! ```
-//!
-//! Metadata allows specifying all settings and variables
-//! that are available in a real rust project:
-//! - crate names via `crate:cratename`
-//! - dependencies via `deps:dep1,dep2`
-//! - configuration settings via `cfg:dbg=false,opt_level=2`
-//! - environment variables via `env:PATH=/bin,RUST_LOG=debug`
-//!
-//! Example using all available metadata:
-//! ```
-//! "
-//! //- /lib.rs crate:foo deps:bar,baz cfg:foo=a,bar=b env:OUTDIR=path/to,OTHER=foo
-//! fn insert_source_code_here() {}
-//! "
-//! ```
 use std::{mem, str::FromStr, sync::Arc};
 use cfg::CfgOptions;
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 003821981..eba46a056 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -53,13 +53,14 @@ use hir_def::{
 use hir_expand::{diagnostics::DiagnosticSink, name::name, MacroDefKind};
 use hir_ty::{
    autoderef, could_unify,
-    method_resolution::{self, TyFingerprint},
+    method_resolution::{self, def_crates, TyFingerprint},
    primitive::UintTy,
+    subst_prefix,
    traits::FnTrait,
    AliasEq, AliasTy, BoundVar, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast,
-    DebruijnIndex, InEnvironment, Interner, QuantifiedWhereClause, Scalar, Solution,
+    DebruijnIndex, InEnvironment, Interner, QuantifiedWhereClause, Scalar, Solution, Substitution,
-    SolutionVariables, Substitution, TraitEnvironment, Ty, TyBuilder, TyDefId, TyKind,
+    TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyDefId, TyExt, TyKind, TyVariableKind,
-    TyVariableKind, WhereClause,
+    WhereClause,
 };
 use itertools::Itertools;
 use rustc_hash::FxHashSet;
@@ -1503,7 +1504,7 @@ impl TypeParam {
        let krate = self.id.parent.module(db.upcast()).krate();
        let ty = params.get(local_idx)?.clone();
        let subst = TyBuilder::type_params_subst(db, self.id.parent);
-        let ty = ty.substitute(&Interner, &subst.prefix(local_idx));
+        let ty = ty.substitute(&Interner, &subst_prefix(&subst, local_idx));
        Some(Type::new_with_resolver_inner(db, krate, &resolver, ty))
    }
 }
@@ -1568,7 +1569,7 @@ impl Impl {
    }
    pub fn all_for_type(db: &dyn HirDatabase, Type { krate, ty, .. }: Type) -> Vec<Impl> {
-        let def_crates = match ty.def_crates(db, krate) {
+        let def_crates = match def_crates(db, &ty, krate) {
            Some(def_crates) => def_crates,
            None => return Vec::new(),
        };
@@ -1579,11 +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))
@@ -1591,13 +1605,12 @@ impl Impl {
            .chain(def_crates.iter().copied())
            .unique()
        {
-            match fp {
+            all.extend(
-                Some(fp) => all.extend(
+                db.trait_impls_in_crate(id)
-                    db.trait_impls_in_crate(id).for_self_ty(fp).map(Self::from).filter(filter),
+                    .for_self_ty_without_blanket_impls(fp)
-                ),
+                    .map(Self::from)
-                None => all
+                    .filter(filter),
-                    .extend(db.trait_impls_in_crate(id).all_impls().map(Self::from).filter(filter)),
+            );
-            }
        }
        all
    }
@@ -1790,7 +1803,7 @@ impl Type {
            .build();
        let goal = Canonical {
-            value: hir_ty::InEnvironment::new(self.env.env.clone(), trait_ref.cast(&Interner)),
+            value: hir_ty::InEnvironment::new(&self.env.env, trait_ref.cast(&Interner)),
            binders: CanonicalVarKinds::empty(&Interner),
        };
@@ -1807,9 +1820,9 @@ impl Type {
            .push(self.ty.clone())
            .fill(args.iter().map(|t| t.ty.clone()))
            .build();
-        let goal = Canonical::new(
+        let goal = hir_ty::make_canonical(
            InEnvironment::new(
-                self.env.env.clone(),
+                &self.env.env,
                AliasEq {
                    alias: AliasTy::Projection(projection),
                    ty: TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
@@ -1821,9 +1834,10 @@ impl Type {
        );
        match db.trait_solve(self.krate, goal)? {
-            Solution::Unique(SolutionVariables(subst)) => subst
+            Solution::Unique(s) => s
                .value
-                .interned()
+                .subst
+                .as_slice(&Interner)
                .first()
                .map(|ty| self.derived(ty.assert_ty_ref(&Interner).clone())),
            Solution::Ambig(_) => None,
@@ -1887,9 +1901,10 @@ impl Type {
                    substs.iter(&Interner).filter_map(|a| a.ty(&Interner)).any(go)
                }
-                TyKind::Array(ty) | TyKind::Slice(ty) | TyKind::Raw(_, ty) | TyKind::Ref(_, ty) => {
+                TyKind::Array(ty, _)
-                    go(ty)
+                | TyKind::Slice(ty)
-                }
+                | TyKind::Raw(_, ty)
+                | TyKind::Ref(_, _, ty) => go(ty),
                TyKind::Scalar(_)
                | TyKind::Str
@@ -1900,7 +1915,9 @@ impl Type {
                | TyKind::Dyn(_)
                | TyKind::Function(_)
                | TyKind::Alias(_)
-                | TyKind::Foreign(_) => false,
+                | TyKind::Foreign(_)
+                | TyKind::Generator(..)
+                | TyKind::GeneratorWitness(..) => false,
            }
        }
    }
@@ -1953,7 +1970,7 @@ impl Type {
        krate: Crate,
        mut callback: impl FnMut(AssocItem) -> Option<T>,
    ) -> Option<T> {
-        for krate in self.ty.def_crates(db, krate.id)? {
+        for krate in def_crates(db, &self.ty, krate.id)? {
            let impls = db.inherent_impls_in_crate(krate);
            for impl_def in impls.for_self_ty(&self.ty) {
@@ -1970,9 +1987,9 @@ impl Type {
    pub fn type_parameters(&self) -> impl Iterator<Item = Type> + '_ {
        self.ty
            .strip_references()
-            .substs()
+            .as_adt()
            .into_iter()
-            .flat_map(|substs| substs.iter(&Interner))
+            .flat_map(|(_, substs)| substs.iter(&Interner))
            .filter_map(|arg| arg.ty(&Interner).cloned())
            .map(move |ty| self.derived(ty))
    }
@@ -2113,18 +2130,22 @@ impl Type {
        fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
            let ty = type_.ty.strip_references();
            match ty.kind(&Interner) {
-                TyKind::Adt(..) => {
+                TyKind::Adt(_, substs) => {
                    cb(type_.derived(ty.clone()));
+                    walk_substs(db, type_, &substs, cb);
                }
-                TyKind::AssociatedType(..) => {
+                TyKind::AssociatedType(_, substs) => {
                    if let Some(_) = ty.associated_type_parent_trait(db) {
                        cb(type_.derived(ty.clone()));
                    }
+                    walk_substs(db, type_, &substs, cb);
                }
-                TyKind::OpaqueType(..) => {
+                TyKind::OpaqueType(_, subst) => {
                    if let Some(bounds) = ty.impl_trait_bounds(db) {
                        walk_bounds(db, &type_.derived(ty.clone()), &bounds, cb);
                    }
+                    walk_substs(db, type_, subst, cb);
                }
                TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
                    if let Some(bounds) = ty.impl_trait_bounds(db) {
@@ -2147,15 +2168,24 @@ impl Type {
                    );
                }
-                TyKind::Ref(_, ty) | TyKind::Raw(_, ty) | TyKind::Array(ty) | TyKind::Slice(ty) => {
+                TyKind::Ref(_, _, ty)
+                | TyKind::Raw(_, ty)
+                | TyKind::Array(ty, _)
+                | TyKind::Slice(ty) => {
                    walk_type(db, &type_.derived(ty.clone()), cb);
                }
+                TyKind::FnDef(_, substs)
+                | TyKind::Tuple(_, substs)
+                | TyKind::Closure(.., substs) => {
+                    walk_substs(db, type_, &substs, cb);
+                }
+                TyKind::Function(hir_ty::FnPointer { substitution, .. }) => {
+                    walk_substs(db, type_, &substitution.0, cb);
+                }
                _ => {}
            }
-            if let Some(substs) = ty.substs() {
-                walk_substs(db, type_, &substs, cb);
-            }
        }
        walk_type(db, self, &mut cb);
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 4ce1c2080..847d2537d 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -20,7 +20,7 @@ use hir_def::{
 use hir_expand::{hygiene::Hygiene, name::AsName, HirFileId, InFile};
 use hir_ty::{
    diagnostics::{record_literal_missing_fields, record_pattern_missing_fields},
-    InferenceResult, Interner, Substitution, TyLoweringContext,
+    InferenceResult, Interner, Substitution, TyExt, TyLoweringContext,
 };
 use syntax::{
    ast::{self, AstNode},
@@ -161,14 +161,15 @@ impl SourceAnalyzer {
        db: &dyn HirDatabase,
        field: &ast::RecordExprField,
    ) -> Option<(Field, Option<Local>)> {
-        let expr_id =
+        let record_expr = ast::RecordExpr::cast(field.syntax().parent().and_then(|p| p.parent())?)?;
-            self.body_source_map.as_ref()?.node_field(InFile::new(self.file_id, field))?;
+        let expr = ast::Expr::from(record_expr);
+        let expr_id = self.body_source_map.as_ref()?.node_expr(InFile::new(self.file_id, &expr))?;
+        let local_name = field.field_name()?.as_name();
        let local = if field.name_ref().is_some() {
            None
        } else {
-            let local_name = field.field_name()?.as_name();
+            let path = ModPath::from_segments(PathKind::Plain, once(local_name.clone()));
-            let path = ModPath::from_segments(PathKind::Plain, once(local_name));
            match self.resolver.resolve_path_in_value_ns_fully(db.upcast(), &path) {
                Some(ValueNs::LocalBinding(pat_id)) => {
                    Some(Local { pat_id, parent: self.resolver.body_owner()? })
@@ -176,18 +177,24 @@ impl SourceAnalyzer {
                _ => None,
            }
        };
-        let struct_field = self.infer.as_ref()?.record_field_resolution(expr_id)?;
+        let variant = self.infer.as_ref()?.variant_resolution_for_expr(expr_id)?;
-        Some((struct_field.into(), local))
+        let variant_data = variant.variant_data(db.upcast());
+        let field = FieldId { parent: variant, local_id: variant_data.field(&local_name)? };
+        Some((field.into(), local))
    }
    pub(crate) fn resolve_record_pat_field(
        &self,
-        _db: &dyn HirDatabase,
+        db: &dyn HirDatabase,
        field: &ast::RecordPatField,
    ) -> Option<Field> {
-        let pat_id = self.pat_id(&field.pat()?)?;
+        let field_name = field.field_name()?.as_name();
-        let struct_field = self.infer.as_ref()?.record_pat_field_resolution(pat_id)?;
+        let record_pat = ast::RecordPat::cast(field.syntax().parent().and_then(|p| p.parent())?)?;
-        Some(struct_field.into())
+        let pat_id = self.pat_id(&record_pat.into())?;
+        let variant = self.infer.as_ref()?.variant_resolution_for_pat(pat_id)?;
+        let variant_data = variant.variant_data(db.upcast());
+        let field = FieldId { parent: variant, local_id: variant_data.field(&field_name)? };
+        Some(field.into())
    }
    pub(crate) fn resolve_macro_call(
@@ -299,7 +306,7 @@ impl SourceAnalyzer {
        let infer = self.infer.as_ref()?;
        let expr_id = self.expr_id(db, &literal.clone().into())?;
-        let substs = infer.type_of_expr[expr_id].substs()?;
+        let substs = infer.type_of_expr[expr_id].as_adt()?.1;
        let (variant, missing_fields, _exhaustive) =
            record_literal_missing_fields(db, infer, expr_id, &body[expr_id])?;
@@ -317,7 +324,7 @@ impl SourceAnalyzer {
        let infer = self.infer.as_ref()?;
        let pat_id = self.pat_id(&pattern.clone().into())?;
-        let substs = infer.type_of_pat[pat_id].substs()?;
+        let substs = infer.type_of_pat[pat_id].as_adt()?.1;
        let (variant, missing_fields, _exhaustive) =
            record_pattern_missing_fields(db, infer, pat_id, &body[pat_id])?;
diff --git a/crates/hir_def/src/attr.rs b/crates/hir_def/src/attr.rs
index ab77d924a..786fad6e1 100644
--- a/crates/hir_def/src/attr.rs
+++ b/crates/hir_def/src/attr.rs
@@ -9,14 +9,14 @@ 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;
 use smallvec::{smallvec, SmallVec};
 use syntax::{
    ast::{self, AstNode, AttrsOwner},
-    match_ast, AstToken, SmolStr, SyntaxNode, TextRange, TextSize,
+    match_ast, AstPtr, AstToken, SmolStr, SyntaxNode, TextRange, TextSize,
 };
 use tt::Subtree;
@@ -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 {
+            .flat_map(|(i, attr)| {
-                Either::Left(attr) => Attr::from_src(attr, hygiene, i as u32),
+                let index = AttrId(i as u32);
-                Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
+                match attr {
-                    index: i as u32,
+                    Either::Left(attr) => Attr::from_src(attr, hygiene, index),
-                    input: Some(AttrInput::Literal(SmolStr::new(doc))),
+                    Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
-                    path: Interned::new(ModPath::from(hir_expand::name!(doc))),
+                        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()?;
@@ -215,12 +218,11 @@ impl Attrs {
        let mut res = ArenaMap::default();
        for (id, fld) in src.value.iter() {
-            let attrs = match fld {
+            let owner: &dyn AttrsOwner = match fld {
-                Either::Left(_tuple) => Attrs::default(),
+                Either::Left(tuple) => tuple,
-                Either::Right(record) => {
+                Either::Right(record) => record,
-                    RawAttrs::from_attrs_owner(db, src.with_value(record)).filter(db, krate)
-                }
            };
+            let attrs = RawAttrs::from_attrs_owner(db, src.with_value(owner)).filter(db, krate);
            res.insert(id, attrs);
        }
@@ -404,10 +406,14 @@ impl AttrsWithOwner {
                return AttrSourceMap { attrs };
            }
            AttrDefId::FieldId(id) => {
-                id.parent.child_source(db).map(|source| match &source[id.local_id] {
+                let map = db.fields_attrs_source_map(id.parent);
-                    Either::Left(field) => ast::AttrsOwnerNode::new(field.clone()),
+                let file_id = id.parent.file_id(db);
-                    Either::Right(field) => ast::AttrsOwnerNode::new(field.clone()),
+                let root = db.parse_or_expand(file_id).unwrap();
-                })
+                let owner = match &map[id.local_id] {
+                    Either::Left(it) => ast::AttrsOwnerNode::new(it.to_node(&root)),
+                    Either::Right(it) => ast::AttrsOwnerNode::new(it.to_node(&root)),
+                };
+                InFile::new(file_id, owner)
            }
            AttrDefId::AdtId(adt) => match adt {
                AdtId::StructId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
@@ -415,10 +421,12 @@ impl AttrsWithOwner {
                AdtId::EnumId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
            },
            AttrDefId::FunctionId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
-            AttrDefId::EnumVariantId(id) => id
+            AttrDefId::EnumVariantId(id) => {
-                .parent
+                let map = db.variants_attrs_source_map(id.parent);
-                .child_source(db)
+                let file_id = id.parent.lookup(db).id.file_id();
-                .map(|source| ast::AttrsOwnerNode::new(source[id.local_id].clone())),
+                let root = db.parse_or_expand(file_id).unwrap();
+                InFile::new(file_id, ast::AttrsOwnerNode::new(map[id.local_id].to_node(&root)))
+            }
            AttrDefId::StaticId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
            AttrDefId::ConstId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
            AttrDefId::TraitId(id) => id.lookup(db).source(db).map(ast::AttrsOwnerNode::new),
@@ -463,7 +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
@@ -555,8 +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)
+            .get(attr.id.0 as usize)
-            .unwrap_or_else(|| panic!("cannot find `Attr` at index {}", attr.index))
+            .unwrap_or_else(|| panic!("cannot find `Attr` at index {:?}", attr.id))
            .as_ref()
    }
 }
@@ -567,7 +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 {
@@ -580,7 +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
@@ -601,7 +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>,
 }
@@ -615,7 +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() {
@@ -628,7 +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
@@ -743,7 +751,38 @@ 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();
+    docs.chain(attrs).sorted_by_key(|&(offset, _)| offset).map(|(_, attr)| attr)
+}
+pub(crate) fn variants_attrs_source_map(
+    db: &dyn DefDatabase,
+    def: EnumId,
+) -> Arc<ArenaMap<LocalEnumVariantId, AstPtr<ast::Variant>>> {
+    let mut res = ArenaMap::default();
+    let child_source = def.child_source(db);
+    for (idx, variant) in child_source.value.iter() {
+        res.insert(idx, AstPtr::new(variant));
+    }
+    Arc::new(res)
+}
+pub(crate) fn fields_attrs_source_map(
+    db: &dyn DefDatabase,
+    def: VariantId,
+) -> Arc<ArenaMap<LocalFieldId, Either<AstPtr<ast::TupleField>, AstPtr<ast::RecordField>>>> {
+    let mut res = ArenaMap::default();
+    let child_source = def.child_source(db);
+    for (idx, variant) in child_source.value.iter() {
+        res.insert(
+            idx,
+            variant
+                .as_ref()
+                .either(|l| Either::Left(AstPtr::new(l)), |r| Either::Right(AstPtr::new(r))),
+        );
+    }
-    attrs.into_iter().map(|(_, attr)| attr)
+    Arc::new(res)
 }
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 63e89a1f4..ed07d6928 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -30,6 +30,7 @@ use crate::{
        LabelId, Literal, LogicOp, MatchArm, Ordering, Pat, PatId, RecordFieldPat, RecordLitField,
        Statement,
    },
+    intern::Interned,
    item_scope::BuiltinShadowMode,
    path::{GenericArgs, Path},
    type_ref::{Mutability, Rawness, TypeRef},
@@ -322,8 +323,10 @@ impl ExprCollector<'_> {
                    Vec::new()
                };
                let method_name = e.name_ref().map(|nr| nr.as_name()).unwrap_or_else(Name::missing);
-                let generic_args =
+                let generic_args = e
-                    e.generic_arg_list().and_then(|it| GenericArgs::from_ast(&self.ctx(), it));
+                    .generic_arg_list()
+                    .and_then(|it| GenericArgs::from_ast(&self.ctx(), it))
+                    .map(Box::new);
                self.alloc_expr(
                    Expr::MethodCall { receiver, method_name, args, generic_args },
                    syntax_ptr,
@@ -385,7 +388,7 @@ impl ExprCollector<'_> {
                self.alloc_expr(Expr::Yield { expr }, syntax_ptr)
            }
            ast::Expr::RecordExpr(e) => {
-                let path = e.path().and_then(|path| self.expander.parse_path(path));
+                let path = e.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                let record_lit = if let Some(nfl) = e.record_expr_field_list() {
                    let fields = nfl
                        .fields()
@@ -430,7 +433,7 @@ impl ExprCollector<'_> {
            }
            ast::Expr::CastExpr(e) => {
                let expr = self.collect_expr_opt(e.expr());
-                let type_ref = TypeRef::from_ast_opt(&self.ctx(), e.ty());
+                let type_ref = Interned::new(TypeRef::from_ast_opt(&self.ctx(), e.ty()));
                self.alloc_expr(Expr::Cast { expr, type_ref }, syntax_ptr)
            }
            ast::Expr::RefExpr(e) => {
@@ -464,13 +467,16 @@ impl ExprCollector<'_> {
                if let Some(pl) = e.param_list() {
                    for param in pl.params() {
                        let pat = self.collect_pat_opt(param.pat());
-                        let type_ref = param.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                        let type_ref =
+                            param.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                        args.push(pat);
                        arg_types.push(type_ref);
                    }
                }
-                let ret_type =
+                let ret_type = e
-                    e.ret_type().and_then(|r| r.ty()).map(|it| TypeRef::from_ast(&self.ctx(), it));
+                    .ret_type()
+                    .and_then(|r| r.ty())
+                    .map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                let body = self.collect_expr_opt(e.body());
                self.alloc_expr(Expr::Lambda { args, arg_types, ret_type, body }, syntax_ptr)
            }
@@ -525,8 +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()),
@@ -549,7 +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,
    ) {
@@ -625,7 +632,8 @@ impl ExprCollector<'_> {
                    return;
                }
                let pat = self.collect_pat_opt(stmt.pat());
-                let type_ref = stmt.ty().map(|it| TypeRef::from_ast(&self.ctx(), it));
+                let type_ref =
+                    stmt.ty().map(|it| Interned::new(TypeRef::from_ast(&self.ctx(), it)));
                let initializer = stmt.initializer().map(|e| self.collect_expr(e));
                self.statements_in_scope.push(Statement::Let { pat, type_ref, initializer });
            }
@@ -636,10 +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| {
+                    self.collect_macro_call(
-                        match expansion {
+                        m,
+                        macro_ptr,
+                        false,
+                        |this, expansion| match expansion {
                            Some(expansion) => {
                                let statements: ast::MacroStmts = expansion;
@@ -653,8 +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));
@@ -755,7 +767,7 @@ impl ExprCollector<'_> {
                }
            }
            ast::Pat::TupleStructPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                let (args, ellipsis) = self.collect_tuple_pat(p.fields());
                Pat::TupleStruct { path, args, ellipsis }
            }
@@ -765,7 +777,7 @@ impl ExprCollector<'_> {
                Pat::Ref { pat, mutability }
            }
            ast::Pat::PathPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                path.map(Pat::Path).unwrap_or(Pat::Missing)
            }
            ast::Pat::OrPat(p) => {
@@ -779,7 +791,7 @@ impl ExprCollector<'_> {
            }
            ast::Pat::WildcardPat(_) => Pat::Wild,
            ast::Pat::RecordPat(p) => {
-                let path = p.path().and_then(|path| self.expander.parse_path(path));
+                let path = p.path().and_then(|path| self.expander.parse_path(path)).map(Box::new);
                let args: Vec<_> = p
                    .record_pat_field_list()
                    .expect("every struct should have a field list")
@@ -841,8 +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/body/tests.rs b/crates/hir_def/src/body/tests.rs
index faa133297..c1d3e998f 100644
--- a/crates/hir_def/src/body/tests.rs
+++ b/crates/hir_def/src/body/tests.rs
@@ -143,7 +143,7 @@ fn f() {
  //^^^^^^^^^^^^^ could not convert tokens
    env!("OUT_DIR");
-  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "load out dirs from check" to fix
+  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
    compile_error!("compile_error works");
  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ compile_error works
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/db.rs b/crates/hir_def/src/db.rs
index 9b7a213a1..7eadc8e0d 100644
--- a/crates/hir_def/src/db.rs
+++ b/crates/hir_def/src/db.rs
@@ -2,9 +2,10 @@
 use std::sync::Arc;
 use base_db::{salsa, CrateId, SourceDatabase, Upcast};
+use either::Either;
 use hir_expand::{db::AstDatabase, HirFileId};
 use la_arena::ArenaMap;
-use syntax::SmolStr;
+use syntax::{ast, AstPtr, SmolStr};
 use crate::{
    adt::{EnumData, StructData},
@@ -122,6 +123,18 @@ pub trait DefDatabase: InternDatabase + AstDatabase + Upcast<dyn AstDatabase> {
    #[salsa::invoke(Attrs::fields_attrs_query)]
    fn fields_attrs(&self, def: VariantId) -> Arc<ArenaMap<LocalFieldId, Attrs>>;
+    #[salsa::invoke(crate::attr::variants_attrs_source_map)]
+    fn variants_attrs_source_map(
+        &self,
+        def: EnumId,
+    ) -> Arc<ArenaMap<LocalEnumVariantId, AstPtr<ast::Variant>>>;
+    #[salsa::invoke(crate::attr::fields_attrs_source_map)]
+    fn fields_attrs_source_map(
+        &self,
+        def: VariantId,
+    ) -> Arc<ArenaMap<LocalFieldId, Either<AstPtr<ast::TupleField>, AstPtr<ast::RecordField>>>>;
    #[salsa::invoke(AttrsWithOwner::attrs_query)]
    fn attrs(&self, def: AttrDefId) -> AttrsWithOwner;
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index 6c7376fad..b4ad984bd 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -18,6 +18,7 @@ use syntax::ast::RangeOp;
 use crate::{
    builtin_type::{BuiltinFloat, BuiltinInt, BuiltinUint},
+    intern::Interned,
    path::{GenericArgs, Path},
    type_ref::{Mutability, Rawness, TypeRef},
    BlockId,
@@ -86,7 +87,7 @@ pub enum Expr {
        receiver: ExprId,
        method_name: Name,
        args: Vec<ExprId>,
-        generic_args: Option<GenericArgs>,
+        generic_args: Option<Box<GenericArgs>>,
    },
    Match {
        expr: ExprId,
@@ -106,7 +107,7 @@ pub enum Expr {
        expr: Option<ExprId>,
    },
    RecordLit {
-        path: Option<Path>,
+        path: Option<Box<Path>>,
        fields: Vec<RecordLitField>,
        spread: Option<ExprId>,
    },
@@ -131,7 +132,7 @@ pub enum Expr {
    },
    Cast {
        expr: ExprId,
-        type_ref: TypeRef,
+        type_ref: Interned<TypeRef>,
    },
    Ref {
        expr: ExprId,
@@ -161,8 +162,8 @@ pub enum Expr {
    },
    Lambda {
        args: Vec<PatId>,
-        arg_types: Vec<Option<TypeRef>>,
+        arg_types: Vec<Option<Interned<TypeRef>>>,
-        ret_type: Option<TypeRef>,
+        ret_type: Option<Interned<TypeRef>>,
        body: ExprId,
    },
    Tuple {
@@ -240,7 +241,7 @@ pub struct RecordLitField {
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub enum Statement {
-    Let { pat: PatId, type_ref: Option<TypeRef>, initializer: Option<ExprId> },
+    Let { pat: PatId, type_ref: Option<Interned<TypeRef>>, initializer: Option<ExprId> },
    Expr(ExprId),
 }
@@ -412,13 +413,13 @@ pub enum Pat {
    Wild,
    Tuple { args: Vec<PatId>, ellipsis: Option<usize> },
    Or(Vec<PatId>),
-    Record { path: Option<Path>, args: Vec<RecordFieldPat>, ellipsis: bool },
+    Record { path: Option<Box<Path>>, args: Vec<RecordFieldPat>, ellipsis: bool },
    Range { start: ExprId, end: ExprId },
    Slice { prefix: Vec<PatId>, slice: Option<PatId>, suffix: Vec<PatId> },
-    Path(Path),
+    Path(Box<Path>),
    Lit(ExprId),
    Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
-    TupleStruct { path: Option<Path>, args: Vec<PatId>, ellipsis: Option<usize> },
+    TupleStruct { path: Option<Box<Path>>, args: Vec<PatId>, ellipsis: Option<usize> },
    Ref { pat: PatId, mutability: Mutability },
    Box { inner: PatId },
    ConstBlock(ExprId),
diff --git a/crates/hir_def/src/item_scope.rs b/crates/hir_def/src/item_scope.rs
index a8ee5eeac..9014468ea 100644
--- a/crates/hir_def/src/item_scope.rs
+++ b/crates/hir_def/src/item_scope.rs
@@ -11,7 +11,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use stdx::format_to;
 use crate::{
-    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ImplId,
+    db::DefDatabase, per_ns::PerNs, visibility::Visibility, AdtId, BuiltinType, ConstId, ImplId,
    LocalModuleId, MacroDefId, ModuleDefId, ModuleId, TraitId,
 };
@@ -37,6 +37,7 @@ pub struct ItemScope {
    defs: Vec<ModuleDefId>,
    impls: Vec<ImplId>,
+    unnamed_consts: Vec<ConstId>,
    /// Traits imported via `use Trait as _;`.
    unnamed_trait_imports: FxHashMap<TraitId, Visibility>,
    /// Macros visible in current module in legacy textual scope
@@ -106,6 +107,10 @@ impl ItemScope {
            .map(|(_, v)| v)
    }
+    pub fn unnamed_consts(&self) -> impl Iterator<Item = ConstId> + '_ {
+        self.unnamed_consts.iter().copied()
+    }
    /// Iterate over all module scoped macros
    pub(crate) fn macros<'a>(&'a self) -> impl Iterator<Item = (&'a Name, MacroDefId)> + 'a {
        self.entries().filter_map(|(name, def)| def.take_macros().map(|macro_| (name, macro_)))
@@ -156,6 +161,10 @@ impl ItemScope {
        self.impls.push(imp)
    }
+    pub(crate) fn define_unnamed_const(&mut self, konst: ConstId) {
+        self.unnamed_consts.push(konst);
+    }
    pub(crate) fn define_legacy_macro(&mut self, name: Name, mac: MacroDefId) {
        self.legacy_macros.insert(name, mac);
    }
@@ -295,6 +304,7 @@ impl ItemScope {
            unresolved,
            defs,
            impls,
+            unnamed_consts,
            unnamed_trait_imports,
            legacy_macros,
        } = self;
@@ -304,6 +314,7 @@ impl ItemScope {
        unresolved.shrink_to_fit();
        defs.shrink_to_fit();
        impls.shrink_to_fit();
+        unnamed_consts.shrink_to_fit();
        unnamed_trait_imports.shrink_to_fit();
        legacy_macros.shrink_to_fit();
    }
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 be9a5e1a0..d69116d51 100644
--- a/crates/hir_def/src/lib.rs
+++ b/crates/hir_def/src/lib.rs
@@ -56,12 +56,13 @@ use std::{
    sync::Arc,
 };
+use adt::VariantData;
 use base_db::{impl_intern_key, salsa, CrateId};
 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;
@@ -442,6 +443,26 @@ pub enum VariantId {
 }
 impl_from!(EnumVariantId, StructId, UnionId for VariantId);
+impl VariantId {
+    pub fn variant_data(self, db: &dyn db::DefDatabase) -> Arc<VariantData> {
+        match self {
+            VariantId::StructId(it) => db.struct_data(it).variant_data.clone(),
+            VariantId::UnionId(it) => db.union_data(it).variant_data.clone(),
+            VariantId::EnumVariantId(it) => {
+                db.enum_data(it.parent).variants[it.local_id].variant_data.clone()
+            }
+        }
+    }
+    pub fn file_id(self, db: &dyn db::DefDatabase) -> HirFileId {
+        match self {
+            VariantId::EnumVariantId(it) => it.parent.lookup(db).id.file_id(),
+            VariantId::StructId(it) => it.lookup(db).id.file_id(),
+            VariantId::UnionId(it) => it.lookup(db).id.file_id(),
+        }
+    }
+}
 trait Intern {
    type ID;
    fn intern(self, db: &dyn db::DefDatabase) -> Self::ID;
@@ -669,13 +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>,
@@ -686,7 +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) => {
+                        MacroCallKind::FnLike { ast_id } => {
-                            let node = ast.to_node(db.upcast());
+                            let node = ast_id.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)), None)
                        }
-                        MacroCallKind::Derive(ast, name) => {
+                        MacroCallKind::Derive { ast_id, derive_name, .. } => {
-                            let node = ast.to_node(db.upcast());
+                            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) => {
+                        MacroCallKind::FnLike { ast_id, .. } => {
-                            let node = ast.to_node(db.upcast());
+                            let node = ast_id.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                            (ast_id.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
                        }
-                        MacroCallKind::Derive(ast, _) => {
+                        MacroCallKind::Derive { ast_id, .. } => {
-                            let node = ast.to_node(db.upcast());
+                            let node = ast_id.to_node(db.upcast());
-                            (ast.file_id, SyntaxNodePtr::from(AstPtr::new(&node)))
+                            (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 f42f92702..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()
@@ -831,12 +832,16 @@ impl DefCollector<'_> {
                        Err(UnresolvedMacro) | Ok(Err(_)) => {}
                    }
                }
-                MacroDirectiveKind::Derive { ast_id } => {
+                MacroDirectiveKind::Derive { ast_id, derive_attr } => {
-                    match derive_macro_as_call_id(ast_id, self.db, self.def_map.krate, |path| {
+                    match derive_macro_as_call_id(
-                        self.resolve_derive_macro(directive.module_id, &path)
+                        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, 0));
+                            resolved.push((directive.module_id, call_id, directive.depth));
                            res = ReachedFixedPoint::No;
                            return false;
                        }
@@ -1163,19 +1168,27 @@ impl ModCollector<'_, '_> {
                }
                ModItem::Const(id) => {
                    let it = &self.item_tree[id];
+                    let const_id = ConstLoc {
-                    if let Some(name) = &it.name {
+                        container: module.into(),
-                        def = Some(DefData {
+                        id: ItemTreeId::new(self.file_id, id),
-                            id: ConstLoc {
+                    }
-                                container: module.into(),
+                    .intern(self.def_collector.db);
-                                id: ItemTreeId::new(self.file_id, id),
-                            }
+                    match &it.name {
-                            .intern(self.def_collector.db)
+                        Some(name) => {
-                            .into(),
+                            def = Some(DefData {
-                            name,
+                                id: const_id.into(),
-                            visibility: &self.item_tree[it.visibility],
+                                name,
-                            has_constructor: false,
+                                visibility: &self.item_tree[it.visibility],
-                        });
+                                has_constructor: false,
+                            });
+                        }
+                        None => {
+                            // const _: T = ...;
+                            self.def_collector.def_map.modules[self.module_id]
+                                .scope
+                                .define_unnamed_const(const_id);
+                        }
                    }
                }
                ModItem::Static(id) => {
@@ -1360,7 +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 },
                        });
                    }
                }
@@ -1512,7 +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
+        let from_extern_prelude = self
-        // from the crate DefMap.
+            .extern_prelude
-        let from_extern_prelude = match self.block {
+            .get(name)
-            Some(_) => PerNs::none(),
+            .map_or(PerNs::none(), |&it| PerNs::types(it, Visibility::Public));
-            None => 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 {
+    fn resolve_name_in_crate_root_or_extern_prelude(
-        let from_crate_root = self[self.root].scope.get(name);
+        &self,
-        let from_extern_prelude = self.resolve_name_in_extern_prelude(name);
+        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_def/src/nameres/tests/diagnostics.rs b/crates/hir_def/src/nameres/tests/diagnostics.rs
index fefdadb22..1ac88fc89 100644
--- a/crates/hir_def/src/nameres/tests/diagnostics.rs
+++ b/crates/hir_def/src/nameres/tests/diagnostics.rs
@@ -233,7 +233,7 @@ fn good_out_dir_diagnostic() {
        macro_rules! concat { () => {} }
        include!(concat!(env!("OUT_DIR"), "/out.rs"));
-      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "load out dirs from check" to fix
+      //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
        "#,
    );
 }
diff --git a/crates/hir_def/src/path.rs b/crates/hir_def/src/path.rs
index f9c8328f0..b528ff8ba 100644
--- a/crates/hir_def/src/path.rs
+++ b/crates/hir_def/src/path.rs
@@ -289,6 +289,12 @@ impl From<Name> for Path {
    }
 }
+impl From<Name> for Box<Path> {
+    fn from(name: Name) -> Box<Path> {
+        Box::new(Path::from(name))
+    }
+}
 impl From<Name> for ModPath {
    fn from(name: Name) -> ModPath {
        ModPath::from_segments(PathKind::Plain, iter::once(name))
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 75ec4196b..80365fc16 100644
--- a/crates/hir_expand/src/builtin_macro.rs
+++ b/crates/hir_expand/src/builtin_macro.rs
@@ -490,7 +490,7 @@ fn env_expand(
        // unnecessary diagnostics for eg. `CARGO_PKG_NAME`.
        if key == "OUT_DIR" {
            err = Some(mbe::ExpandError::Other(
-                r#"`OUT_DIR` not set, enable "load out dirs from check" to fix"#.into(),
+                r#"`OUT_DIR` not set, enable "run build scripts" to fix"#.into(),
            ));
        }
@@ -566,10 +566,9 @@ mod tests {
                let loc = MacroCallLoc {
                    def,
                    krate,
-                    kind: MacroCallKind::FnLike(AstId::new(
+                    kind: MacroCallKind::FnLike {
-                        file_id.into(),
+                        ast_id: AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call)),
-                        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 =
+    let id: MacroCallId = def
-        def.as_lazy_macro(db, krate, MacroCallKind::FnLike(macro_call.with_value(ast_id))).into();
+        .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>),
+    FnLike { ast_id: AstId<ast::MacroCall> },
-    Derive(AstId<ast::Item>, String),
+    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::FnLike { ast_id, .. } => ast_id.file_id,
-            MacroCallKind::Derive(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::FnLike { ast_id, .. } => {
-            MacroCallKind::Derive(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 7ca4af80e..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,
+    db::HirDatabase, static_lifetime, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds,
-    InEnvironment, Interner, Solution, Ty, TyBuilder, TyKind,
+    DebruijnIndex, InEnvironment, Interner, ProjectionTyExt, Solution, Substitution, Ty, TyBuilder,
+    TyKind,
 };
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
@@ -35,13 +36,21 @@ pub(crate) fn deref(
    krate: CrateId,
    ty: InEnvironment<&Canonical<Ty>>,
 ) -> Option<Canonical<Ty>> {
-    if let Some(derefed) = ty.goal.value.builtin_deref() {
+    if let Some(derefed) = builtin_deref(&ty.goal.value) {
        Some(Canonical { value: derefed, binders: ty.goal.binders.clone() })
    } else {
        deref_by_trait(db, krate, ty)
    }
 }
+fn builtin_deref(ty: &Ty) -> Option<Ty> {
+    match ty.kind(&Interner) {
+        TyKind::Ref(.., ty) => Some(ty.clone()),
+        TyKind::Raw(.., ty) => Some(ty.clone()),
+        _ => None,
+    }
+}
 fn deref_by_trait(
    db: &dyn HirDatabase,
    krate: CrateId,
@@ -95,7 +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,
            ))),
        ),
@@ -120,23 +129,25 @@ fn deref_by_trait(
            // assumptions will be broken. We would need to properly introduce
            // new variables in that case
-            for i in 1..vars.0.binders.len(&Interner) {
+            for i in 1..vars.binders.len(&Interner) {
-                if vars.0.value.at(&Interner, i - 1).assert_ty_ref(&Interner).kind(&Interner)
+                if vars.value.subst.at(&Interner, i - 1).assert_ty_ref(&Interner).kind(&Interner)
                    != &TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, i - 1))
                {
                    warn!("complex solution for derefing {:?}: {:?}, ignoring", ty.goal, solution);
                    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
-                    .0
                    .value
-                    .at(&Interner, vars.0.value.len(&Interner) - 1)
+                    .subst
+                    .at(&Interner, vars.value.subst.len(&Interner) - 1)
                    .assert_ty_ref(&Interner)
                    .clone(),
-                binders: vars.0.binders.clone(),
+                binders: vars.binders.clone(),
-            })
+            }))
        }
        Solution::Ambig(_) => {
            info!("Ambiguous solution for derefing {:?}: {:?}", ty.goal, solution);
@@ -144,3 +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/builder.rs b/crates/hir_ty/src/builder.rs
index 9b2c6975a..e25ef866d 100644
--- a/crates/hir_ty/src/builder.rs
+++ b/crates/hir_ty/src/builder.rs
@@ -4,6 +4,7 @@ use std::iter;
 use chalk_ir::{
    cast::{Cast, CastTo, Caster},
+    fold::Fold,
    interner::HasInterner,
    AdtId, BoundVar, DebruijnIndex, Safety, Scalar,
 };
@@ -12,8 +13,8 @@ use smallvec::SmallVec;
 use crate::{
    db::HirDatabase, primitive, to_assoc_type_id, to_chalk_trait_id, utils::generics, Binders,
-    CallableSig, FnPointer, FnSig, GenericArg, Interner, ProjectionTy, Substitution, TraitRef, Ty,
+    CallableSig, FnPointer, FnSig, FnSubst, GenericArg, Interner, ProjectionTy, Substitution,
-    TyDefId, TyKind, TypeWalk, ValueTyDefId,
+    TraitRef, Ty, TyDefId, TyExt, TyKind, ValueTyDefId,
 };
 /// This is a builder for `Ty` or anything that needs a `Substitution`.
@@ -32,8 +33,7 @@ impl<D> TyBuilder<D> {
    fn build_internal(self) -> (D, Substitution) {
        assert_eq!(self.vec.len(), self.param_count);
-        // FIXME: would be good to have a way to construct a chalk_ir::Substitution from the interned form
+        let subst = Substitution::from_iter(&Interner, self.vec);
-        let subst = Substitution::intern(self.vec);
        (self.data, subst)
    }
@@ -78,9 +78,12 @@ impl TyBuilder<()> {
    pub fn fn_ptr(sig: CallableSig) -> Ty {
        TyKind::Function(FnPointer {
-            num_args: sig.params().len(),
+            num_binders: 0,
            sig: FnSig { abi: (), safety: Safety::Safe, variadic: sig.is_varargs },
-            substs: Substitution::from_iter(&Interner, sig.params_and_return.iter().cloned()),
+            substitution: FnSubst(Substitution::from_iter(
+                &Interner,
+                sig.params_and_return.iter().cloned(),
+            )),
        })
        .intern(&Interner)
    }
@@ -138,7 +141,7 @@ impl TyBuilder<hir_def::AdtId> {
                self.vec.push(fallback().cast(&Interner));
            } else {
                // each default can depend on the previous parameters
-                let subst_so_far = Substitution::intern(self.vec.clone());
+                let subst_so_far = Substitution::from_iter(&Interner, self.vec.clone());
                self.vec
                    .push(default_ty.clone().substitute(&Interner, &subst_so_far).cast(&Interner));
            }
@@ -193,13 +196,13 @@ impl TyBuilder<TypeAliasId> {
    }
 }
-impl<T: TypeWalk + HasInterner<Interner = Interner>> TyBuilder<Binders<T>> {
+impl<T: HasInterner<Interner = Interner> + Fold<Interner>> TyBuilder<Binders<T>> {
    fn subst_binders(b: Binders<T>) -> Self {
        let param_count = b.binders.len(&Interner);
        TyBuilder::new(b, param_count)
    }
-    pub fn build(self) -> T {
+    pub fn build(self) -> <T as Fold<Interner>>::Result {
        let (b, subst) = self.build_internal();
        b.substitute(&Interner, &subst)
    }
diff --git a/crates/hir_ty/src/chalk_cast.rs b/crates/hir_ty/src/chalk_cast.rs
deleted file mode 100644
index df6492113..000000000
--- a/crates/hir_ty/src/chalk_cast.rs
+++ /dev/null
@@ -1,73 +0,0 @@
-//! Implementations of the Chalk `Cast` trait for our types.
-use chalk_ir::{
-    cast::{Cast, CastTo},
-    interner::HasInterner,
-};
-use crate::{AliasEq, DomainGoal, GenericArg, GenericArgData, Interner, TraitRef, Ty, WhereClause};
-macro_rules! has_interner {
-    ($t:ty) => {
-        impl HasInterner for $t {
-            type Interner = crate::Interner;
-        }
-    };
-}
-has_interner!(WhereClause);
-has_interner!(DomainGoal);
-has_interner!(GenericArg);
-has_interner!(Ty);
-impl CastTo<WhereClause> for TraitRef {
-    fn cast_to(self, _interner: &Interner) -> WhereClause {
-        WhereClause::Implemented(self)
-    }
-}
-impl CastTo<WhereClause> for AliasEq {
-    fn cast_to(self, _interner: &Interner) -> WhereClause {
-        WhereClause::AliasEq(self)
-    }
-}
-impl CastTo<DomainGoal> for WhereClause {
-    fn cast_to(self, _interner: &Interner) -> DomainGoal {
-        DomainGoal::Holds(self)
-    }
-}
-impl CastTo<GenericArg> for Ty {
-    fn cast_to(self, interner: &Interner) -> GenericArg {
-        GenericArg::new(interner, GenericArgData::Ty(self))
-    }
-}
-macro_rules! transitive_impl {
-    ($a:ty, $b:ty, $c:ty) => {
-        impl CastTo<$c> for $a {
-            fn cast_to(self, interner: &Interner) -> $c {
-                self.cast::<$b>(interner).cast(interner)
-            }
-        }
-    };
-}
-// In Chalk, these can be done as blanket impls, but that doesn't work here
-// because of coherence
-transitive_impl!(TraitRef, WhereClause, DomainGoal);
-transitive_impl!(AliasEq, WhereClause, DomainGoal);
-macro_rules! reflexive_impl {
-    ($a:ty) => {
-        impl CastTo<$a> for $a {
-            fn cast_to(self, _interner: &Interner) -> $a {
-                self
-            }
-        }
-    };
-}
-reflexive_impl!(GenericArg);
diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/chalk_db.rs
index dff87ef70..8f054d06b 100644
--- a/crates/hir_ty/src/traits/chalk.rs
+++ b/crates/hir_ty/src/chalk_db.rs
@@ -1,52 +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,
+    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,
+    AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, Interner, ProjectionTy,
-    TraitRef, Ty, TyBuilder, TyKind, WhereClause,
+    ProjectionTyExt, QuantifiedWhereClause, Substitution, TraitRef, TraitRefExt, Ty, TyBuilder,
+    TyExt, TyKind, WhereClause,
 };
-use mapping::{
-    convert_where_clauses, generic_predicate_to_inline_bound, make_binders, TypeAliasAsValue,
-};
-pub use self::interner::Interner;
-pub(crate) use self::interner::*;
-pub(super) mod tls;
+pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
-mod interner;
+pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
-mod mapping;
+pub(crate) type StructDatum = chalk_solve::rust_ir::AdtDatum<Interner>;
+pub(crate) type ImplDatum = chalk_solve::rust_ir::ImplDatum<Interner>;
-pub(crate) trait ToChalk {
+pub(crate) type OpaqueTyDatum = chalk_solve::rust_ir::OpaqueTyDatum<Interner>;
-    type Chalk;
-    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk;
+pub(crate) type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
-    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self;
+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) fn from_chalk<T, ChalkT>(db: &dyn HirDatabase, chalk: ChalkT) -> T
+pub(crate) type AssociatedTyValueId = chalk_solve::rust_ir::AssociatedTyValueId<Interner>;
-where
+pub(crate) type AssociatedTyValue = chalk_solve::rust_ir::AssociatedTyValue<Interner>;
-    T: ToChalk<Chalk = ChalkT>,
+pub(crate) type FnDefDatum = chalk_solve::rust_ir::FnDefDatum<Interner>;
-{
+pub(crate) type Variances = chalk_ir::Variances<Interner>;
-    T::from_chalk(db, chalk)
-}
 impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
    fn associated_ty_data(&self, id: AssocTypeId) -> Arc<AssociatedTyDatum> {
@@ -84,9 +79,9 @@ 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 = from_chalk(self.db, parameters[0].assert_ty_ref(&Interner).clone());
+        let ty: Ty = parameters[0].assert_ty_ref(&Interner).clone();
        fn binder_kind(
            ty: &Ty,
@@ -103,7 +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,
@@ -166,7 +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(
@@ -187,16 +182,11 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
                let (datas, binders) = (*datas).as_ref().into_value_and_skipped_binders();
                let data = &datas.impl_traits[idx as usize];
                let bound = OpaqueTyDatumBound {
-                    bounds: make_binders(
+                    bounds: make_only_type_binders(
-                        data.bounds
-                            .skip_binders()
-                            .iter()
-                            .cloned()
-                            .map(|b| b.to_chalk(self.db))
-                            .collect(),
                        1,
+                        data.bounds.skip_binders().iter().cloned().collect(),
                    ),
-                    where_clauses: make_binders(vec![], 0),
+                    where_clauses: make_only_type_binders(0, vec![]),
                };
                chalk_ir::Binders::new(binders, bound)
            }
@@ -220,7 +210,8 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
                    let impl_bound = WhereClause::Implemented(TraitRef {
                        trait_id: to_chalk_trait_id(future_trait),
                        // Self type as the first parameter.
-                        substitution: Substitution::single(
+                        substitution: Substitution::from1(
+                            &Interner,
                            TyKind::BoundVar(BoundVar {
                                debruijn: DebruijnIndex::INNERMOST,
                                index: 0,
@@ -232,7 +223,8 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
                        alias: AliasTy::Projection(ProjectionTy {
                            associated_ty_id: to_assoc_type_id(future_output),
                            // Self type as the first parameter.
-                            substitution: Substitution::single(
+                            substitution: Substitution::from1(
+                                &Interner,
                                TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
                                    .intern(&Interner),
                            ),
@@ -242,25 +234,25 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
                            .intern(&Interner),
                    });
                    let bound = OpaqueTyDatumBound {
-                        bounds: make_binders(
+                        bounds: make_only_type_binders(
+                            1,
                            vec![
-                                wrap_in_empty_binders(impl_bound).to_chalk(self.db),
+                                crate::wrap_empty_binders(impl_bound),
-                                wrap_in_empty_binders(proj_bound).to_chalk(self.db),
+                                crate::wrap_empty_binders(proj_bound),
                            ],
-                            1,
                        ),
-                        where_clauses: make_binders(vec![], 0),
+                        where_clauses: make_only_type_binders(0, vec![]),
                    };
                    // The opaque type has 1 parameter.
-                    make_binders(bound, 1)
+                    make_only_type_binders(1, bound)
                } else {
                    // If failed to find Symbol’s value as variable is void: Future::Output, return empty bounds as fallback.
                    let bound = OpaqueTyDatumBound {
-                        bounds: make_binders(vec![], 0),
+                        bounds: make_only_type_binders(0, vec![]),
-                        where_clauses: make_binders(vec![], 0),
+                        where_clauses: make_only_type_binders(0, vec![]),
                    };
                    // The opaque type has 1 parameter.
-                    make_binders(bound, 1)
+                    make_only_type_binders(1, bound)
                }
            }
        };
@@ -270,7 +262,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
    fn hidden_opaque_type(&self, _id: chalk_ir::OpaqueTyId<Interner>) -> chalk_ir::Ty<Interner> {
        // FIXME: actually provide the hidden type; it is relevant for auto traits
-        TyKind::Error.intern(&Interner).to_chalk(self.db)
+        TyKind::Error.intern(&Interner)
    }
    fn is_object_safe(&self, _trait_id: chalk_ir::TraitId<Interner>) -> bool {
@@ -291,33 +283,32 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
        _closure_id: chalk_ir::ClosureId<Interner>,
        substs: &chalk_ir::Substitution<Interner>,
    ) -> chalk_ir::Binders<rust_ir::FnDefInputsAndOutputDatum<Interner>> {
-        let sig_ty: Ty =
+        let sig_ty = substs.at(&Interner, 0).assert_ty_ref(&Interner).clone();
-            from_chalk(self.db, substs.at(&Interner, 0).assert_ty_ref(&Interner).clone());
        let sig = &sig_ty.callable_sig(self.db).expect("first closure param should be fn ptr");
        let io = rust_ir::FnDefInputsAndOutputDatum {
-            argument_types: sig.params().iter().map(|ty| ty.clone().to_chalk(self.db)).collect(),
+            argument_types: sig.params().iter().cloned().collect(),
-            return_type: sig.ret().clone().to_chalk(self.db),
+            return_type: sig.ret().clone(),
        };
-        make_binders(io.shifted_in(&Interner), 0)
+        make_only_type_binders(0, io.shifted_in(&Interner))
    }
    fn closure_upvars(
        &self,
        _closure_id: chalk_ir::ClosureId<Interner>,
        _substs: &chalk_ir::Substitution<Interner>,
    ) -> chalk_ir::Binders<chalk_ir::Ty<Interner>> {
-        let ty = TyBuilder::unit().to_chalk(self.db);
+        let ty = TyBuilder::unit();
-        make_binders(ty, 0)
+        make_only_type_binders(0, ty)
    }
    fn closure_fn_substitution(
        &self,
        _closure_id: chalk_ir::ClosureId<Interner>,
        _substs: &chalk_ir::Substitution<Interner>,
    ) -> chalk_ir::Substitution<Interner> {
-        Substitution::empty(&Interner).to_chalk(self.db)
+        Substitution::empty(&Interner)
    }
    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 {
@@ -408,10 +399,10 @@ pub(crate) fn associated_ty_data_query(
    let where_clauses = convert_where_clauses(db, type_alias.into(), &bound_vars);
    let bound_data = rust_ir::AssociatedTyDatumBound { bounds, where_clauses };
    let datum = AssociatedTyDatum {
-        trait_id: trait_.to_chalk(db),
+        trait_id: to_chalk_trait_id(trait_),
        id,
        name: type_alias,
-        binders: make_binders(bound_data, generic_params.len()),
+        binders: make_only_type_binders(generic_params.len(), bound_data),
    };
    Arc::new(datum)
 }
@@ -422,7 +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());
@@ -444,7 +435,7 @@ pub(crate) fn trait_datum_query(
        lang_attr(db.upcast(), trait_).and_then(|name| well_known_trait_from_lang_attr(&name));
    let trait_datum = TraitDatum {
        id: trait_id,
-        binders: make_binders(trait_datum_bound, bound_vars.len(&Interner)),
+        binders: make_only_type_binders(bound_vars.len(&Interner), trait_datum_bound),
        flags,
        associated_ty_ids,
        well_known,
@@ -513,7 +504,7 @@ pub(crate) fn struct_datum_query(
        // FIXME set ADT kind
        kind: rust_ir::AdtKind::Struct,
        id: struct_id,
-        binders: make_binders(struct_datum_bound, num_params),
+        binders: make_only_type_binders(num_params, struct_datum_bound),
        flags,
    };
    Arc::new(struct_datum)
@@ -561,7 +552,6 @@ fn impl_def_datum(
        trait_ref.display(db),
        where_clauses
    );
-    let trait_ref = trait_ref.to_chalk(db);
    let polarity = if negative { rust_ir::Polarity::Negative } else { rust_ir::Polarity::Positive };
@@ -583,7 +573,7 @@ fn impl_def_datum(
        .collect();
    debug!("impl_datum: {:?}", impl_datum_bound);
    let impl_datum = ImplDatum {
-        binders: make_binders(impl_datum_bound, bound_vars.len(&Interner)),
+        binders: make_only_type_binders(bound_vars.len(&Interner), impl_datum_bound),
        impl_type,
        polarity,
        associated_ty_value_ids,
@@ -622,7 +612,7 @@ fn type_alias_associated_ty_value(
        .associated_type_by_name(&type_alias_data.name)
        .expect("assoc ty value should not exist"); // validated when building the impl data as well
    let (ty, binders) = db.ty(type_alias.into()).into_value_and_skipped_binders();
-    let value_bound = rust_ir::AssociatedTyValueBound { ty: ty.to_chalk(db) };
+    let value_bound = rust_ir::AssociatedTyValueBound { ty };
    let value = rust_ir::AssociatedTyValue {
        impl_id: impl_id.to_chalk(db),
        associated_ty_id: to_assoc_type_id(assoc_ty),
@@ -643,13 +633,13 @@ pub(crate) fn fn_def_datum_query(
    let where_clauses = convert_where_clauses(db, callable_def.into(), &bound_vars);
    let bound = rust_ir::FnDefDatumBound {
        // Note: Chalk doesn't actually use this information yet as far as I am aware, but we provide it anyway
-        inputs_and_output: make_binders(
+        inputs_and_output: make_only_type_binders(
+            0,
            rust_ir::FnDefInputsAndOutputDatum {
-                argument_types: sig.params().iter().map(|ty| ty.clone().to_chalk(db)).collect(),
+                argument_types: sig.params().iter().cloned().collect(),
-                return_type: sig.ret().clone().to_chalk(db),
+                return_type: sig.ret().clone(),
            }
            .shifted_in(&Interner),
-            0,
        ),
        where_clauses,
    };
@@ -686,42 +676,65 @@ pub(crate) fn adt_variance_query(
    )
 }
-impl From<FnDefId> for crate::db::InternedCallableDefId {
+pub(super) fn convert_where_clauses(
-    fn from(fn_def_id: FnDefId) -> Self {
+    db: &dyn HirDatabase,
-        InternKey::from_intern_id(fn_def_id.0)
+    def: GenericDefId,
-    }
+    substs: &Substitution,
-}
+) -> Vec<chalk_ir::QuantifiedWhereClause<Interner>> {
+    let generic_predicates = db.generic_predicates(def);
-impl From<crate::db::InternedCallableDefId> for FnDefId {
+    let mut result = Vec::with_capacity(generic_predicates.len());
-    fn from(callable_def_id: crate::db::InternedCallableDefId) -> Self {
+    for pred in generic_predicates.iter() {
-        chalk_ir::FnDefId(callable_def_id.as_intern_id())
+        result.push(pred.clone().substitute(&Interner, substs));
-    }
+    }
-}
+    result
-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> {
+pub(super) fn generic_predicate_to_inline_bound(
-    fn from(id: crate::db::InternedClosureId) -> Self {
+    db: &dyn HirDatabase,
-        chalk_ir::ClosureId(id.as_intern_id())
+    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,
    }
 }
-fn wrap_in_empty_binders<T: crate::TypeWalk>(value: T) -> crate::Binders<T> {
-    crate::Binders::wrap_empty(value)
-}
diff --git a/crates/hir_ty/src/chalk_ext.rs b/crates/hir_ty/src/chalk_ext.rs
index b7463366b..8c4542956 100644
--- a/crates/hir_ty/src/chalk_ext.rs
+++ b/crates/hir_ty/src/chalk_ext.rs
@@ -1,13 +1,305 @@
 //! Various extensions traits for Chalk types.
-use crate::{Interner, Ty, TyKind};
+use chalk_ir::Mutability;
+use hir_def::{
+    type_ref::Rawness, AssocContainerId, FunctionId, GenericDefId, HasModule, Lookup, TraitId,
+};
+use crate::{
+    db::HirDatabase, from_assoc_type_id, from_chalk_trait_id, from_foreign_def_id,
+    from_placeholder_idx, to_chalk_trait_id, AdtId, AliasEq, AliasTy, Binders, CallableDefId,
+    CallableSig, FnPointer, ImplTraitId, Interner, Lifetime, ProjectionTy, QuantifiedWhereClause,
+    Substitution, TraitRef, Ty, TyBuilder, TyKind, WhereClause,
+};
 pub trait TyExt {
    fn is_unit(&self) -> bool;
+    fn is_never(&self) -> bool;
+    fn is_unknown(&self) -> bool;
+    fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)>;
+    fn as_tuple(&self) -> Option<&Substitution>;
+    fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId>;
+    fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)>;
+    fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)>;
+    fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId>;
+    fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId>;
+    fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig>;
+    fn strip_references(&self) -> &Ty;
+    /// If this is a `dyn Trait`, returns that trait.
+    fn dyn_trait(&self) -> Option<TraitId>;
+    fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>>;
+    fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId>;
+    /// FIXME: Get rid of this, it's not a good abstraction
+    fn equals_ctor(&self, other: &Ty) -> bool;
 }
 impl TyExt for Ty {
    fn is_unit(&self) -> bool {
        matches!(self.kind(&Interner), TyKind::Tuple(0, _))
    }
+    fn is_never(&self) -> bool {
+        matches!(self.kind(&Interner), TyKind::Never)
+    }
+    fn is_unknown(&self) -> bool {
+        matches!(self.kind(&Interner), TyKind::Error)
+    }
+    fn as_adt(&self) -> Option<(hir_def::AdtId, &Substitution)> {
+        match self.kind(&Interner) {
+            TyKind::Adt(AdtId(adt), parameters) => Some((*adt, parameters)),
+            _ => None,
+        }
+    }
+    fn as_tuple(&self) -> Option<&Substitution> {
+        match self.kind(&Interner) {
+            TyKind::Tuple(_, substs) => Some(substs),
+            _ => None,
+        }
+    }
+    fn as_fn_def(&self, db: &dyn HirDatabase) -> Option<FunctionId> {
+        if let Some(CallableDefId::FunctionId(func)) = self.callable_def(db) {
+            Some(func)
+        } else {
+            None
+        }
+    }
+    fn as_reference(&self) -> Option<(&Ty, Lifetime, Mutability)> {
+        match self.kind(&Interner) {
+            TyKind::Ref(mutability, lifetime, ty) => Some((ty, lifetime.clone(), *mutability)),
+            _ => None,
+        }
+    }
+    fn as_reference_or_ptr(&self) -> Option<(&Ty, Rawness, Mutability)> {
+        match self.kind(&Interner) {
+            TyKind::Ref(mutability, _, ty) => Some((ty, Rawness::Ref, *mutability)),
+            TyKind::Raw(mutability, ty) => Some((ty, Rawness::RawPtr, *mutability)),
+            _ => None,
+        }
+    }
+    fn as_generic_def(&self, db: &dyn HirDatabase) -> Option<GenericDefId> {
+        match *self.kind(&Interner) {
+            TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
+            TyKind::FnDef(callable, ..) => {
+                Some(db.lookup_intern_callable_def(callable.into()).into())
+            }
+            TyKind::AssociatedType(type_alias, ..) => Some(from_assoc_type_id(type_alias).into()),
+            TyKind::Foreign(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
+            _ => None,
+        }
+    }
+    fn callable_def(&self, db: &dyn HirDatabase) -> Option<CallableDefId> {
+        match self.kind(&Interner) {
+            &TyKind::FnDef(def, ..) => Some(db.lookup_intern_callable_def(def.into())),
+            _ => None,
+        }
+    }
+    fn callable_sig(&self, db: &dyn HirDatabase) -> Option<CallableSig> {
+        match self.kind(&Interner) {
+            TyKind::Function(fn_ptr) => Some(CallableSig::from_fn_ptr(fn_ptr)),
+            TyKind::FnDef(def, parameters) => {
+                let callable_def = db.lookup_intern_callable_def((*def).into());
+                let sig = db.callable_item_signature(callable_def);
+                Some(sig.substitute(&Interner, &parameters))
+            }
+            TyKind::Closure(.., substs) => {
+                let sig_param = substs.at(&Interner, 0).assert_ty_ref(&Interner);
+                sig_param.callable_sig(db)
+            }
+            _ => None,
+        }
+    }
+    fn dyn_trait(&self) -> Option<TraitId> {
+        let trait_ref = match self.kind(&Interner) {
+            TyKind::Dyn(dyn_ty) => dyn_ty.bounds.skip_binders().interned().get(0).and_then(|b| {
+                match b.skip_binders() {
+                    WhereClause::Implemented(trait_ref) => Some(trait_ref),
+                    _ => None,
+                }
+            }),
+            _ => None,
+        }?;
+        Some(from_chalk_trait_id(trait_ref.trait_id))
+    }
+    fn strip_references(&self) -> &Ty {
+        let mut t: &Ty = self;
+        while let TyKind::Ref(_mutability, _lifetime, ty) = t.kind(&Interner) {
+            t = ty;
+        }
+        t
+    }
+    fn impl_trait_bounds(&self, db: &dyn HirDatabase) -> Option<Vec<QuantifiedWhereClause>> {
+        match self.kind(&Interner) {
+            TyKind::OpaqueType(opaque_ty_id, ..) => {
+                match db.lookup_intern_impl_trait_id((*opaque_ty_id).into()) {
+                    ImplTraitId::AsyncBlockTypeImplTrait(def, _expr) => {
+                        let krate = def.module(db.upcast()).krate();
+                        if let Some(future_trait) = db
+                            .lang_item(krate, "future_trait".into())
+                            .and_then(|item| item.as_trait())
+                        {
+                            // This is only used by type walking.
+                            // Parameters will be walked outside, and projection predicate is not used.
+                            // So just provide the Future trait.
+                            let impl_bound = Binders::empty(
+                                &Interner,
+                                WhereClause::Implemented(TraitRef {
+                                    trait_id: to_chalk_trait_id(future_trait),
+                                    substitution: Substitution::empty(&Interner),
+                                }),
+                            );
+                            Some(vec![impl_bound])
+                        } else {
+                            None
+                        }
+                    }
+                    ImplTraitId::ReturnTypeImplTrait(..) => None,
+                }
+            }
+            TyKind::Alias(AliasTy::Opaque(opaque_ty)) => {
+                let predicates = match db.lookup_intern_impl_trait_id(opaque_ty.opaque_ty_id.into())
+                {
+                    ImplTraitId::ReturnTypeImplTrait(func, idx) => {
+                        db.return_type_impl_traits(func).map(|it| {
+                            let data = (*it)
+                                .as_ref()
+                                .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
+                            data.substitute(&Interner, &opaque_ty.substitution)
+                        })
+                    }
+                    // It always has an parameter for Future::Output type.
+                    ImplTraitId::AsyncBlockTypeImplTrait(..) => unreachable!(),
+                };
+                predicates.map(|it| it.into_value_and_skipped_binders().0)
+            }
+            TyKind::Placeholder(idx) => {
+                let id = from_placeholder_idx(db, *idx);
+                let generic_params = db.generic_params(id.parent);
+                let param_data = &generic_params.types[id.local_id];
+                match param_data.provenance {
+                    hir_def::generics::TypeParamProvenance::ArgumentImplTrait => {
+                        let substs = TyBuilder::type_params_subst(db, id.parent);
+                        let predicates = db
+                            .generic_predicates(id.parent)
+                            .into_iter()
+                            .map(|pred| pred.clone().substitute(&Interner, &substs))
+                            .filter(|wc| match &wc.skip_binders() {
+                                WhereClause::Implemented(tr) => {
+                                    &tr.self_type_parameter(&Interner) == self
+                                }
+                                WhereClause::AliasEq(AliasEq {
+                                    alias: AliasTy::Projection(proj),
+                                    ty: _,
+                                }) => &proj.self_type_parameter(&Interner) == self,
+                                _ => false,
+                            })
+                            .collect::<Vec<_>>();
+                        Some(predicates)
+                    }
+                    _ => None,
+                }
+            }
+            _ => None,
+        }
+    }
+    fn associated_type_parent_trait(&self, db: &dyn HirDatabase) -> Option<TraitId> {
+        match self.kind(&Interner) {
+            TyKind::AssociatedType(id, ..) => {
+                match from_assoc_type_id(*id).lookup(db.upcast()).container {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
+            TyKind::Alias(AliasTy::Projection(projection_ty)) => {
+                match from_assoc_type_id(projection_ty.associated_ty_id)
+                    .lookup(db.upcast())
+                    .container
+                {
+                    AssocContainerId::TraitId(trait_id) => Some(trait_id),
+                    _ => None,
+                }
+            }
+            _ => None,
+        }
+    }
+    fn equals_ctor(&self, other: &Ty) -> bool {
+        match (self.kind(&Interner), other.kind(&Interner)) {
+            (TyKind::Adt(adt, ..), TyKind::Adt(adt2, ..)) => adt == adt2,
+            (TyKind::Slice(_), TyKind::Slice(_)) | (TyKind::Array(_, _), TyKind::Array(_, _)) => {
+                true
+            }
+            (TyKind::FnDef(def_id, ..), TyKind::FnDef(def_id2, ..)) => def_id == def_id2,
+            (TyKind::OpaqueType(ty_id, ..), TyKind::OpaqueType(ty_id2, ..)) => ty_id == ty_id2,
+            (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
+                ty_id == ty_id2
+            }
+            (TyKind::Foreign(ty_id, ..), TyKind::Foreign(ty_id2, ..)) => ty_id == ty_id2,
+            (TyKind::Closure(id1, _), TyKind::Closure(id2, _)) => id1 == id2,
+            (TyKind::Ref(mutability, ..), TyKind::Ref(mutability2, ..))
+            | (TyKind::Raw(mutability, ..), TyKind::Raw(mutability2, ..)) => {
+                mutability == mutability2
+            }
+            (
+                TyKind::Function(FnPointer { num_binders, sig, .. }),
+                TyKind::Function(FnPointer { num_binders: num_binders2, sig: sig2, .. }),
+            ) => num_binders == num_binders2 && sig == sig2,
+            (TyKind::Tuple(cardinality, _), TyKind::Tuple(cardinality2, _)) => {
+                cardinality == cardinality2
+            }
+            (TyKind::Str, TyKind::Str) | (TyKind::Never, TyKind::Never) => true,
+            (TyKind::Scalar(scalar), TyKind::Scalar(scalar2)) => scalar == scalar2,
+            _ => false,
+        }
+    }
+}
+pub trait ProjectionTyExt {
+    fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef;
+    fn trait_(&self, db: &dyn HirDatabase) -> TraitId;
+}
+impl ProjectionTyExt for ProjectionTy {
+    fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef {
+        TraitRef {
+            trait_id: to_chalk_trait_id(self.trait_(db)),
+            substitution: self.substitution.clone(),
+        }
+    }
+    fn trait_(&self, db: &dyn HirDatabase) -> TraitId {
+        match from_assoc_type_id(self.associated_ty_id).lookup(db.upcast()).container {
+            AssocContainerId::TraitId(it) => it,
+            _ => panic!("projection ty without parent trait"),
+        }
+    }
+}
+pub trait TraitRefExt {
+    fn hir_trait_id(&self) -> TraitId;
+}
+impl TraitRefExt for TraitRef {
+    fn hir_trait_id(&self) -> TraitId {
+        from_chalk_trait_id(self.trait_id)
+    }
 }
diff --git a/crates/hir_ty/src/db.rs b/crates/hir_ty/src/db.rs
index 4300680d9..1690926ad 100644
--- a/crates/hir_ty/src/db.rs
+++ b/crates/hir_ty/src/db.rs
@@ -1,18 +1,19 @@
-//! 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;
 use base_db::{impl_intern_key, salsa, CrateId, Upcast};
 use hir_def::{
    db::DefDatabase, expr::ExprId, ConstParamId, DefWithBodyId, FunctionId, GenericDefId, ImplId,
-    LocalFieldId, TypeParamId, VariantId,
+    LifetimeParamId, LocalFieldId, TypeParamId, VariantId,
 };
 use la_arena::ArenaMap;
 use crate::{
+    chalk_db,
    method_resolution::{InherentImpls, TraitImpls},
-    traits::chalk,
+    Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, Interner, PolyFnSig,
-    Binders, CallableDefId, FnDefId, ImplTraitId, InferenceResult, PolyFnSig,
    QuantifiedWhereClause, ReturnTypeImplTraits, TraitRef, Ty, TyDefId, ValueTyDefId,
 };
 use hir_expand::name::Name;
@@ -86,37 +87,46 @@ pub trait HirDatabase: DefDatabase + Upcast<dyn DefDatabase> {
    #[salsa::interned]
    fn intern_type_param_id(&self, param_id: TypeParamId) -> InternedTypeParamId;
    #[salsa::interned]
+    fn intern_lifetime_param_id(&self, param_id: LifetimeParamId) -> InternedLifetimeParamId;
+    #[salsa::interned]
+    fn intern_const_param_id(&self, param_id: ConstParamId) -> InternedConstParamId;
+    #[salsa::interned]
    fn intern_impl_trait_id(&self, id: ImplTraitId) -> InternedOpaqueTyId;
    #[salsa::interned]
    fn intern_closure(&self, id: (DefWithBodyId, ExprId)) -> InternedClosureId;
-    #[salsa::invoke(chalk::associated_ty_data_query)]
+    #[salsa::invoke(chalk_db::associated_ty_data_query)]
-    fn associated_ty_data(&self, id: chalk::AssocTypeId) -> Arc<chalk::AssociatedTyDatum>;
+    fn associated_ty_data(&self, id: chalk_db::AssocTypeId) -> Arc<chalk_db::AssociatedTyDatum>;
-    #[salsa::invoke(chalk::trait_datum_query)]
+    #[salsa::invoke(chalk_db::trait_datum_query)]
-    fn trait_datum(&self, krate: CrateId, trait_id: chalk::TraitId) -> Arc<chalk::TraitDatum>;
+    fn trait_datum(&self, krate: CrateId, trait_id: chalk_db::TraitId)
+        -> Arc<chalk_db::TraitDatum>;
-    #[salsa::invoke(chalk::struct_datum_query)]
+    #[salsa::invoke(chalk_db::struct_datum_query)]
-    fn struct_datum(&self, krate: CrateId, struct_id: chalk::AdtId) -> Arc<chalk::StructDatum>;
+    fn struct_datum(
+        &self,
+        krate: CrateId,
+        struct_id: chalk_db::AdtId,
+    ) -> Arc<chalk_db::StructDatum>;
-    #[salsa::invoke(crate::traits::chalk::impl_datum_query)]
+    #[salsa::invoke(chalk_db::impl_datum_query)]
-    fn impl_datum(&self, krate: CrateId, impl_id: chalk::ImplId) -> Arc<chalk::ImplDatum>;
+    fn impl_datum(&self, krate: CrateId, impl_id: chalk_db::ImplId) -> Arc<chalk_db::ImplDatum>;
-    #[salsa::invoke(crate::traits::chalk::fn_def_datum_query)]
+    #[salsa::invoke(chalk_db::fn_def_datum_query)]
-    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> Arc<chalk::FnDefDatum>;
+    fn fn_def_datum(&self, krate: CrateId, fn_def_id: FnDefId) -> Arc<chalk_db::FnDefDatum>;
-    #[salsa::invoke(crate::traits::chalk::fn_def_variance_query)]
+    #[salsa::invoke(chalk_db::fn_def_variance_query)]
-    fn fn_def_variance(&self, krate: CrateId, fn_def_id: FnDefId) -> chalk::Variances;
+    fn fn_def_variance(&self, krate: CrateId, fn_def_id: FnDefId) -> chalk_db::Variances;
-    #[salsa::invoke(crate::traits::chalk::adt_variance_query)]
+    #[salsa::invoke(chalk_db::adt_variance_query)]
-    fn adt_variance(&self, krate: CrateId, adt_id: chalk::AdtId) -> chalk::Variances;
+    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,
+        id: chalk_db::AssociatedTyValueId,
-    ) -> Arc<chalk::AssociatedTyValue>;
+    ) -> Arc<chalk_db::AssociatedTyValue>;
    #[salsa::invoke(crate::traits::trait_solve_query)]
    fn trait_solve(
@@ -125,12 +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>,
+        env: chalk_ir::Environment<Interner>,
-    ) -> chalk_ir::ProgramClauses<chalk::Interner>;
+    ) -> chalk_ir::ProgramClauses<Interner>;
 }
 fn infer_wait(db: &dyn HirDatabase, def: DefWithBodyId) -> Arc<InferenceResult> {
@@ -156,6 +166,14 @@ pub struct InternedTypeParamId(salsa::InternId);
 impl_intern_key!(InternedTypeParamId);
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct InternedLifetimeParamId(salsa::InternId);
+impl_intern_key!(InternedLifetimeParamId);
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct InternedConstParamId(salsa::InternId);
+impl_intern_key!(InternedConstParamId);
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct InternedOpaqueTyId(salsa::InternId);
 impl_intern_key!(InternedOpaqueTyId);
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/diagnostics/expr.rs b/crates/hir_ty/src/diagnostics/expr.rs
index db278d0db..79602c3dd 100644
--- a/crates/hir_ty/src/diagnostics/expr.rs
+++ b/crates/hir_ty/src/diagnostics/expr.rs
@@ -14,7 +14,6 @@ use crate::{
        MismatchedArgCount, MissingFields, MissingMatchArms, MissingOkOrSomeInTailExpr,