7 files changed, 181 insertions, 132 deletions

diff --git a/crates/hir/Cargo.toml b/crates/hir/Cargo.toml
index 2ef5bcbc9..9e329656f 100644
--- a/crates/hir/Cargo.toml
+++ b/crates/hir/Cargo.toml
@@ -13,7 +13,7 @@ doctest = false
 log = "0.4.8"
 rustc-hash = "1.1.0"
 either = "1.5.3"
-arrayvec = "0.6"
+arrayvec = "0.7"
 itertools = "0.10.0"
 smallvec = "1.4.0"
 
diff --git a/crates/hir/src/db.rs b/crates/hir/src/db.rs
index 1902a8d16..df5758342 100644
--- a/crates/hir/src/db.rs
+++ b/crates/hir/src/db.rs
@@ -1,14 +1,6 @@
 //! FIXME: write short doc here
 
-pub use hir_def::db::{
-    AttrsQuery, BlockDefMapQuery, BodyQuery, BodyWithSourceMapQuery, ConstDataQuery,
-    CrateDefMapQueryQuery, CrateLangItemsQuery, DefDatabase, DefDatabaseStorage, EnumDataQuery,
-    ExprScopesQuery, FileItemTreeQuery, FunctionDataQuery, GenericParamsQuery, ImplDataQuery,
-    ImportMapQuery, InternConstQuery, InternDatabase, InternDatabaseStorage, InternEnumQuery,
-    InternFunctionQuery, InternImplQuery, InternStaticQuery, InternStructQuery, InternTraitQuery,
-    InternTypeAliasQuery, InternUnionQuery, LangItemQuery, StaticDataQuery, StructDataQuery,
-    TraitDataQuery, TypeAliasDataQuery, UnionDataQuery,
-};
+pub use hir_def::db::*;
 pub use hir_expand::db::{
     AstDatabase, AstDatabaseStorage, AstIdMapQuery, HygieneFrameQuery, InternEagerExpansionQuery,
     InternMacroQuery, MacroArgTextQuery, MacroDefQuery, MacroExpandQuery, ParseMacroExpansionQuery,
diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index 97a78ca25..01a4d205f 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -9,33 +9,33 @@ use hir_ty::display::{
     write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
     HirFormatter,
 };
+use hir_ty::Interner;
 use syntax::ast::{self, NameOwner};
 
 use crate::{
     Adt, Const, ConstParam, Enum, Field, Function, GenericParam, HasVisibility, LifetimeParam,
-    Module, Static, Struct, Substitution, Trait, Type, TypeAlias, TypeParam, Union, Variant,
+    Module, Static, Struct, Trait, TyBuilder, Type, TypeAlias, TypeParam, Union, Variant,
 };
 
 impl HirDisplay for Function {
     fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
         let data = f.db.function_data(self.id);
         write_visibility(self.module(f.db).id, self.visibility(f.db), f)?;
-        let qual = &data.qualifier;
-        if qual.is_default {
+        if data.is_default() {
             write!(f, "default ")?;
         }
-        if qual.is_const {
+        if data.is_const() {
             write!(f, "const ")?;
         }
-        if qual.is_async {
+        if data.is_async() {
             write!(f, "async ")?;
         }
-        if qual.is_unsafe {
+        if data.is_unsafe() {
             write!(f, "unsafe ")?;
         }
-        if let Some(abi) = &qual.abi {
+        if let Some(abi) = &data.abi {
             // FIXME: String escape?
-            write!(f, "extern \"{}\" ", abi)?;
+            write!(f, "extern \"{}\" ", &**abi)?;
         }
         write!(f, "fn {}", data.name)?;
 
@@ -68,7 +68,7 @@ impl HirDisplay for Function {
                 write!(f, ", ")?;
             } else {
                 first = false;
-                if data.has_self_param {
+                if data.has_self_param() {
                     write_self_param(type_ref, f)?;
                     continue;
                 }
@@ -88,10 +88,10 @@ impl HirDisplay for Function {
         // `FunctionData::ret_type` will be `::core::future::Future<Output = ...>` for async fns.
         // Use ugly pattern match to strip the Future trait.
         // Better way?
-        let ret_type = if !qual.is_async {
+        let ret_type = if !data.is_async() {
             &data.ret_type
         } else {
-            match &data.ret_type {
+            match &*data.ret_type {
                 TypeRef::ImplTrait(bounds) => match &bounds[0] {
                     TypeBound::Path(path) => {
                         path.segments().iter().last().unwrap().args_and_bindings.unwrap().bindings
@@ -235,8 +235,9 @@ impl HirDisplay for TypeParam {
     fn hir_fmt(&self, f: &mut HirFormatter) -> Result<(), HirDisplayError> {
         write!(f, "{}", self.name(f.db))?;
         let bounds = f.db.generic_predicates_for_param(self.id);
-        let substs = Substitution::type_params(f.db, self.id.parent);
-        let predicates = bounds.iter().cloned().map(|b| b.subst(&substs)).collect::<Vec<_>>();
+        let substs = TyBuilder::type_params_subst(f.db, self.id.parent);
+        let predicates =
+            bounds.iter().cloned().map(|b| b.substitute(&Interner, &substs)).collect::<Vec<_>>();
         if !(predicates.is_empty() || f.omit_verbose_types()) {
             write_bounds_like_dyn_trait_with_prefix(":", &predicates, f)?;
         }
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 05a60e158..0afc06906 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -44,6 +44,7 @@ use hir_def::{
     per_ns::PerNs,
     resolver::{HasResolver, Resolver},
     src::HasSource as _,
+    type_ref::TraitRef,
     AdtId, AssocContainerId, AssocItemId, AssocItemLoc, AttrDefId, ConstId, ConstParamId,
     DefWithBodyId, EnumId, FunctionId, GenericDefId, HasModule, ImplId, LifetimeParamId,
     LocalEnumVariantId, LocalFieldId, Lookup, ModuleId, StaticId, StructId, TraitId, TypeAliasId,
@@ -51,14 +52,15 @@ use hir_def::{
 };
 use hir_expand::{diagnostics::DiagnosticSink, name::name, MacroDefKind};
 use hir_ty::{
-    autoderef,
-    method_resolution::{self, TyFingerprint},
+    autoderef, could_unify,
+    method_resolution::{self, def_crates, TyFingerprint},
     primitive::UintTy,
-    to_assoc_type_id,
-    traits::{FnTrait, Solution, SolutionVariables},
+    subst_prefix,
+    traits::FnTrait,
     AliasEq, AliasTy, BoundVar, CallableDefId, CallableSig, Canonical, CanonicalVarKinds, Cast,
-    DebruijnIndex, InEnvironment, Interner, ProjectionTy, QuantifiedWhereClause, Scalar,
-    Substitution, TraitEnvironment, Ty, TyDefId, TyKind, TyVariableKind, WhereClause,
+    DebruijnIndex, InEnvironment, Interner, QuantifiedWhereClause, Scalar, Solution, Substitution,
+    TraitEnvironment, TraitRefExt, Ty, TyBuilder, TyDefId, TyExt, TyKind, TyVariableKind,
+    WhereClause,
 };
 use itertools::Itertools;
 use rustc_hash::FxHashSet;
@@ -514,8 +516,8 @@ impl Field {
             VariantDef::Union(it) => it.id.into(),
             VariantDef::Variant(it) => it.parent.id.into(),
         };
-        let substs = Substitution::type_params(db, generic_def_id);
-        let ty = db.field_types(var_id)[self.id].clone().subst(&substs);
+        let substs = TyBuilder::type_params_subst(db, generic_def_id);
+        let ty = db.field_types(var_id)[self.id].clone().substitute(&Interner, &substs);
         Type::new(db, self.parent.module(db).id.krate(), var_id, ty)
     }
 
@@ -701,7 +703,7 @@ impl_from!(Struct, Union, Enum for Adt);
 impl Adt {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
         let subst = db.generic_defaults(self.into());
-        subst.iter().any(|ty| ty.value.is_unknown())
+        subst.iter().any(|ty| ty.skip_binders().is_unknown())
     }
 
     /// Turns this ADT into a type. Any type parameters of the ADT will be
@@ -831,7 +833,7 @@ impl Function {
     }
 
     pub fn self_param(self, db: &dyn HirDatabase) -> Option<SelfParam> {
-        if !db.function_data(self.id).has_self_param {
+        if !db.function_data(self.id).has_self_param() {
             return None;
         }
         Some(SelfParam { func: self.id })
@@ -863,7 +865,7 @@ impl Function {
     }
 
     pub fn is_unsafe(self, db: &dyn HirDatabase) -> bool {
-        db.function_data(self.id).qualifier.is_unsafe
+        db.function_data(self.id).is_unsafe()
     }
 
     pub fn diagnostics(self, db: &dyn HirDatabase, sink: &mut DiagnosticSink) {
@@ -877,7 +879,7 @@ impl Function {
     ///
     /// This is false in the case of required (not provided) trait methods.
     pub fn has_body(self, db: &dyn HirDatabase) -> bool {
-        db.function_data(self.id).has_body
+        db.function_data(self.id).has_body()
     }
 
     /// A textual representation of the HIR of this function for debugging purposes.
@@ -956,7 +958,7 @@ impl SelfParam {
         func_data
             .params
             .first()
-            .map(|param| match *param {
+            .map(|param| match &**param {
                 TypeRef::Reference(.., mutability) => match mutability {
                     hir_def::type_ref::Mutability::Shared => Access::Shared,
                     hir_def::type_ref::Mutability::Mut => Access::Exclusive,
@@ -1010,7 +1012,7 @@ impl Const {
     }
 
     pub fn type_ref(self, db: &dyn HirDatabase) -> TypeRef {
-        db.const_data(self.id).type_ref.clone()
+        db.const_data(self.id).type_ref.as_ref().clone()
     }
 }
 
@@ -1088,7 +1090,7 @@ pub struct TypeAlias {
 impl TypeAlias {
     pub fn has_non_default_type_params(self, db: &dyn HirDatabase) -> bool {
         let subst = db.generic_defaults(self.id.into());
-        subst.iter().any(|ty| ty.value.is_unknown())
+        subst.iter().any(|ty| ty.skip_binders().is_unknown())
     }
 
     pub fn module(self, db: &dyn HirDatabase) -> Module {
@@ -1100,7 +1102,7 @@ impl TypeAlias {
     }
 
     pub fn type_ref(self, db: &dyn HirDatabase) -> Option<TypeRef> {
-        db.type_alias_data(self.id).type_ref.clone()
+        db.type_alias_data(self.id).type_ref.as_deref().cloned()
     }
 
     pub fn ty(self, db: &dyn HirDatabase) -> Type {
@@ -1128,7 +1130,7 @@ pub struct BuiltinType {
 impl BuiltinType {
     pub fn ty(self, db: &dyn HirDatabase, module: Module) -> Type {
         let resolver = module.id.resolver(db.upcast());
-        Type::new_with_resolver(db, &resolver, Ty::builtin(self.inner))
+        Type::new_with_resolver(db, &resolver, TyBuilder::builtin(self.inner))
             .expect("crate not present in resolver")
     }
 
@@ -1501,8 +1503,8 @@ impl TypeParam {
         let resolver = self.id.parent.resolver(db.upcast());
         let krate = self.id.parent.module(db.upcast()).krate();
         let ty = params.get(local_idx)?.clone();
-        let subst = Substitution::type_params(db, self.id.parent);
-        let ty = ty.subst(&subst.prefix(local_idx));
+        let subst = TyBuilder::type_params_subst(db, self.id.parent);
+        let ty = ty.substitute(&Interner, &subst_prefix(&subst, local_idx));
         Some(Type::new_with_resolver_inner(db, krate, &resolver, ty))
     }
 }
@@ -1567,15 +1569,15 @@ 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(),
         };
 
         let filter = |impl_def: &Impl| {
-            let target_ty = impl_def.target_ty(db);
-            let rref = target_ty.remove_ref();
-            ty.equals_ctor(rref.as_ref().map_or(&target_ty.ty, |it| &it.ty))
+            let self_ty = impl_def.self_ty(db);
+            let rref = self_ty.remove_ref();
+            ty.equals_ctor(rref.as_ref().map_or(&self_ty.ty, |it| &it.ty))
         };
 
         let mut all = Vec::new();
@@ -1613,16 +1615,16 @@ impl Impl {
 
     // FIXME: the return type is wrong. This should be a hir version of
     // `TraitRef` (ie, resolved `TypeRef`).
-    pub fn target_trait(self, db: &dyn HirDatabase) -> Option<TypeRef> {
-        db.impl_data(self.id).target_trait.clone()
+    pub fn trait_(self, db: &dyn HirDatabase) -> Option<TraitRef> {
+        db.impl_data(self.id).target_trait.as_deref().cloned()
     }
 
-    pub fn target_ty(self, db: &dyn HirDatabase) -> Type {
+    pub fn self_ty(self, db: &dyn HirDatabase) -> Type {
         let impl_data = db.impl_data(self.id);
         let resolver = self.id.resolver(db.upcast());
         let krate = self.id.lookup(db.upcast()).container.krate();
         let ctx = hir_ty::TyLoweringContext::new(db, &resolver);
-        let ty = ctx.lower_ty(&impl_data.target_type);
+        let ty = ctx.lower_ty(&impl_data.self_ty);
         Type::new_with_resolver_inner(db, krate, &resolver, ty)
     }
 
@@ -1702,30 +1704,29 @@ impl Type {
     fn from_def(
         db: &dyn HirDatabase,
         krate: CrateId,
-        def: impl HasResolver + Into<TyDefId> + Into<GenericDefId>,
+        def: impl HasResolver + Into<TyDefId>,
     ) -> Type {
-        let substs = Substitution::build_for_def(db, def).fill_with_unknown().build();
-        let ty = db.ty(def.into()).subst(&substs);
+        let ty = TyBuilder::def_ty(db, def.into()).fill_with_unknown().build();
         Type::new(db, krate, def, ty)
     }
 
     pub fn is_unit(&self) -> bool {
-        matches!(self.ty.interned(&Interner), TyKind::Tuple(0, ..))
+        matches!(self.ty.kind(&Interner), TyKind::Tuple(0, ..))
     }
     pub fn is_bool(&self) -> bool {
-        matches!(self.ty.interned(&Interner), TyKind::Scalar(Scalar::Bool))
+        matches!(self.ty.kind(&Interner), TyKind::Scalar(Scalar::Bool))
     }
 
     pub fn is_mutable_reference(&self) -> bool {
-        matches!(self.ty.interned(&Interner), TyKind::Ref(hir_ty::Mutability::Mut, ..))
+        matches!(self.ty.kind(&Interner), TyKind::Ref(hir_ty::Mutability::Mut, ..))
     }
 
     pub fn is_usize(&self) -> bool {
-        matches!(self.ty.interned(&Interner), TyKind::Scalar(Scalar::Uint(UintTy::Usize)))
+        matches!(self.ty.kind(&Interner), TyKind::Scalar(Scalar::Uint(UintTy::Usize)))
     }
 
     pub fn remove_ref(&self) -> Option<Type> {
-        match &self.ty.interned(&Interner) {
+        match &self.ty.kind(&Interner) {
             TyKind::Ref(.., ty) => Some(self.derived(ty.clone())),
             _ => None,
         }
@@ -1784,16 +1785,13 @@ impl Type {
     }
 
     pub fn impls_trait(&self, db: &dyn HirDatabase, trait_: Trait, args: &[Type]) -> bool {
-        let trait_ref = hir_ty::TraitRef {
-            trait_id: hir_ty::to_chalk_trait_id(trait_.id),
-            substitution: Substitution::build_for_def(db, trait_.id)
-                .push(self.ty.clone())
-                .fill(args.iter().map(|t| t.ty.clone()))
-                .build(),
-        };
+        let trait_ref = TyBuilder::trait_ref(db, trait_.id)
+            .push(self.ty.clone())
+            .fill(args.iter().map(|t| t.ty.clone()))
+            .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),
         };
 
@@ -1803,22 +1801,18 @@ impl Type {
     pub fn normalize_trait_assoc_type(
         &self,
         db: &dyn HirDatabase,
-        trait_: Trait,
         args: &[Type],
         alias: TypeAlias,
     ) -> Option<Type> {
-        let subst = Substitution::build_for_def(db, trait_.id)
+        let projection = TyBuilder::assoc_type_projection(db, alias.id)
             .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(ProjectionTy {
-                        associated_ty_id: to_assoc_type_id(alias.id),
-                        substitution: subst,
-                    }),
+                    alias: AliasTy::Projection(projection),
                     ty: TyKind::BoundVar(BoundVar::new(DebruijnIndex::INNERMOST, 0))
                         .intern(&Interner),
                 }
@@ -1828,9 +1822,12 @@ impl Type {
         );
 
         match db.trait_solve(self.krate, goal)? {
-            Solution::Unique(SolutionVariables(subst)) => {
-                subst.value.first().map(|ty| self.derived(ty.clone()))
-            }
+            Solution::Unique(s) => s
+                .value
+                .subst
+                .interned()
+                .first()
+                .map(|ty| self.derived(ty.assert_ty_ref(&Interner).clone())),
             Solution::Ambig(_) => None,
         }
     }
@@ -1852,15 +1849,15 @@ impl Type {
     }
 
     pub fn is_closure(&self) -> bool {
-        matches!(&self.ty.interned(&Interner), TyKind::Closure { .. })
+        matches!(&self.ty.kind(&Interner), TyKind::Closure { .. })
     }
 
     pub fn is_fn(&self) -> bool {
-        matches!(&self.ty.interned(&Interner), TyKind::FnDef(..) | TyKind::Function { .. })
+        matches!(&self.ty.kind(&Interner), TyKind::FnDef(..) | TyKind::Function { .. })
     }
 
     pub fn is_packed(&self, db: &dyn HirDatabase) -> bool {
-        let adt_id = match self.ty.interned(&Interner) {
+        let adt_id = match self.ty.kind(&Interner) {
             &TyKind::Adt(hir_ty::AdtId(adt_id), ..) => adt_id,
             _ => return false,
         };
@@ -1873,27 +1870,30 @@ impl Type {
     }
 
     pub fn is_raw_ptr(&self) -> bool {
-        matches!(&self.ty.interned(&Interner), TyKind::Raw(..))
+        matches!(&self.ty.kind(&Interner), TyKind::Raw(..))
     }
 
     pub fn contains_unknown(&self) -> bool {
         return go(&self.ty);
 
         fn go(ty: &Ty) -> bool {
-            match ty.interned(&Interner) {
-                TyKind::Unknown => true,
+            match ty.kind(&Interner) {
+                TyKind::Error => true,
 
                 TyKind::Adt(_, substs)
                 | TyKind::AssociatedType(_, substs)
                 | TyKind::Tuple(_, substs)
                 | TyKind::OpaqueType(_, substs)
                 | TyKind::FnDef(_, substs)
-                | TyKind::Closure(_, substs) => substs.iter().any(go),
-
-                TyKind::Array(ty) | TyKind::Slice(ty) | TyKind::Raw(_, ty) | TyKind::Ref(_, ty) => {
-                    go(ty)
+                | TyKind::Closure(_, substs) => {
+                    substs.iter(&Interner).filter_map(|a| a.ty(&Interner)).any(go)
                 }
 
+                TyKind::Array(ty, _)
+                | TyKind::Slice(ty)
+                | TyKind::Raw(_, ty)
+                | TyKind::Ref(_, _, ty) => go(ty),
+
                 TyKind::Scalar(_)
                 | TyKind::Str
                 | TyKind::Never
@@ -1903,13 +1903,13 @@ impl Type {
                 | TyKind::Dyn(_)
                 | TyKind::Function(_)
                 | TyKind::Alias(_)
-                | TyKind::ForeignType(_) => false,
+                | TyKind::Foreign(_) => false,
             }
         }
     }
 
     pub fn fields(&self, db: &dyn HirDatabase) -> Vec<(Field, Type)> {
-        let (variant_id, substs) = match self.ty.interned(&Interner) {
+        let (variant_id, substs) = match self.ty.kind(&Interner) {
             &TyKind::Adt(hir_ty::AdtId(AdtId::StructId(s)), ref substs) => (s.into(), substs),
             &TyKind::Adt(hir_ty::AdtId(AdtId::UnionId(u)), ref substs) => (u.into(), substs),
             _ => return Vec::new(),
@@ -1919,15 +1919,18 @@ impl Type {
             .iter()
             .map(|(local_id, ty)| {
                 let def = Field { parent: variant_id.into(), id: local_id };
-                let ty = ty.clone().subst(substs);
+                let ty = ty.clone().substitute(&Interner, substs);
                 (def, self.derived(ty))
             })
             .collect()
     }
 
     pub fn tuple_fields(&self, _db: &dyn HirDatabase) -> Vec<Type> {
-        if let TyKind::Tuple(_, substs) = &self.ty.interned(&Interner) {
-            substs.iter().map(|ty| self.derived(ty.clone())).collect()
+        if let TyKind::Tuple(_, substs) = &self.ty.kind(&Interner) {
+            substs
+                .iter(&Interner)
+                .map(|ty| self.derived(ty.assert_ty_ref(&Interner).clone()))
+                .collect()
         } else {
             Vec::new()
         }
@@ -1953,7 +1956,7 @@ 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) {
@@ -1970,10 +1973,11 @@ 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())
-            .map(move |ty| self.derived(ty.clone()))
+            .flat_map(|(_, substs)| substs.iter(&Interner))
+            .filter_map(|arg| arg.ty(&Interner).cloned())
+            .map(move |ty| self.derived(ty))
     }
 
     pub fn iterate_method_candidates<T>(
@@ -2079,7 +2083,7 @@ impl Type {
             substs: &Substitution,
             cb: &mut impl FnMut(Type),
         ) {
-            for ty in substs.iter() {
+            for ty in substs.iter(&Interner).filter_map(|a| a.ty(&Interner)) {
                 walk_type(db, &type_.derived(ty.clone()), cb);
             }
         }
@@ -2095,7 +2099,12 @@ impl Type {
                     WhereClause::Implemented(trait_ref) => {
                         cb(type_.clone());
                         // skip the self type. it's likely the type we just got the bounds from
-                        for ty in trait_ref.substitution.iter().skip(1) {
+                        for ty in trait_ref
+                            .substitution
+                            .iter(&Interner)
+                            .skip(1)
+                            .filter_map(|a| a.ty(&Interner))
+                        {
                             walk_type(db, &type_.derived(ty.clone()), cb);
                         }
                     }
@@ -2106,19 +2115,23 @@ impl Type {
 
         fn walk_type(db: &dyn HirDatabase, type_: &Type, cb: &mut impl FnMut(Type)) {
             let ty = type_.ty.strip_references();
-            match ty.interned(&Interner) {
-                TyKind::Adt(..) => {
+            match ty.kind(&Interner) {
+                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) {
@@ -2141,19 +2154,32 @@ 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);
     }
+
+    pub fn could_unify_with(&self, other: &Type) -> bool {
+        could_unify(&self.ty, &other.ty)
+    }
 }
 
 // FIXME: closures
diff --git a/crates/hir/src/semantics.rs b/crates/hir/src/semantics.rs
index 1198e3f0b..7955bf0b5 100644
--- a/crates/hir/src/semantics.rs
+++ b/crates/hir/src/semantics.rs
@@ -76,9 +76,11 @@ impl PathResolution {
     pub fn assoc_type_shorthand_candidates<R>(
         &self,
         db: &dyn HirDatabase,
-        mut cb: impl FnMut(TypeAlias) -> Option<R>,
+        mut cb: impl FnMut(&Name, TypeAlias) -> Option<R>,
     ) -> Option<R> {
-        associated_type_shorthand_candidates(db, self.in_type_ns()?, |_, _, id| cb(id.into()))
+        associated_type_shorthand_candidates(db, self.in_type_ns()?, |name, _, id| {
+            cb(name, id.into())
+        })
     }
 }
 
@@ -445,7 +447,7 @@ impl<'db> SemanticsImpl<'db> {
                 }
             };
             gpl.lifetime_params()
-                .find(|tp| tp.lifetime().as_ref().map(|lt| lt.text()) == Some(text))
+                .find(|tp| tp.lifetime().as_ref().map(|lt| lt.text()).as_ref() == Some(&text))
         })?;
         let src = self.find_file(lifetime_param.syntax().clone()).with_value(lifetime_param);
         ToDef::to_def(self, src)
@@ -492,9 +494,9 @@ impl<'db> SemanticsImpl<'db> {
     fn resolve_method_call_as_callable(&self, call: &ast::MethodCallExpr) -> Option<Callable> {
         // FIXME: this erases Substs
         let func = self.resolve_method_call(call)?;
-        let ty = self.db.value_ty(func.into());
+        let (ty, _) = self.db.value_ty(func.into()).into_value_and_skipped_binders();
         let resolver = self.analyze(call.syntax()).resolver;
-        let ty = Type::new_with_resolver(self.db, &resolver, ty.value)?;
+        let ty = Type::new_with_resolver(self.db, &resolver, ty)?;
         let mut res = ty.as_callable(self.db)?;
         res.is_bound_method = true;
         Some(res)
@@ -768,7 +770,7 @@ to_def_impls![
     (crate::TypeParam, ast::TypeParam, type_param_to_def),
     (crate::LifetimeParam, ast::LifetimeParam, lifetime_param_to_def),
     (crate::ConstParam, ast::ConstParam, const_param_to_def),
-    (crate::MacroDef, ast::MacroRules, macro_rules_to_def),
+    (crate::MacroDef, ast::Macro, macro_to_def),
     (crate::Local, ast::IdentPat, bind_pat_to_def),
     (crate::Local, ast::SelfParam, self_param_to_def),
     (crate::Label, ast::Label, label_to_def),
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index 762809fcd..9a5a2255f 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -191,10 +191,7 @@ impl SourceToDefCtx<'_, '_> {
     }
 
     // FIXME: use DynMap as well?
-    pub(super) fn macro_rules_to_def(
-        &mut self,
-        src: InFile<ast::MacroRules>,
-    ) -> Option<MacroDefId> {
+    pub(super) fn macro_to_def(&mut self, src: InFile<ast::Macro>) -> Option<MacroDefId> {
         let file_ast_id = self.db.ast_id_map(src.file_id).ast_id(&src.value);
         let ast_id = AstId::new(src.file_id, file_ast_id.upcast());
         let kind = MacroDefKind::Declarative(ast_id);
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 37d162b32..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, Substitution,
+    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 =
-            self.body_source_map.as_ref()?.node_field(InFile::new(self.file_id, field))?;
+        let record_expr = ast::RecordExpr::cast(field.syntax().parent().and_then(|p| p.parent())?)?;
+        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));
+            let path = ModPath::from_segments(PathKind::Plain, once(local_name.clone()));
             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)?;
-        Some((struct_field.into(), local))
+        let variant = self.infer.as_ref()?.variant_resolution_for_expr(expr_id)?;
+        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 struct_field = self.infer.as_ref()?.record_pat_field_resolution(pat_id)?;
-        Some(struct_field.into())
+        let field_name = field.field_name()?.as_name();
+        let record_pat = ast::RecordPat::cast(field.syntax().parent().and_then(|p| p.parent())?)?;
+        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])?;
@@ -339,7 +346,7 @@ impl SourceAnalyzer {
             .into_iter()
             .map(|local_id| {
                 let field = FieldId { parent: variant, local_id };
-                let ty = field_types[local_id].clone().subst(substs);
+                let ty = field_types[local_id].clone().substitute(&Interner, substs);
                 (field.into(), Type::new_with_resolver_inner(db, krate, &self.resolver, ty))
             })
             .collect()
@@ -466,7 +473,21 @@ fn resolve_hir_path_(
     prefer_value_ns: bool,
 ) -> Option<PathResolution> {
     let types = || {
-        resolver.resolve_path_in_type_ns_fully(db.upcast(), path.mod_path()).map(|ty| match ty {
+        let (ty, unresolved) = match path.type_anchor() {
+            Some(type_ref) => {
+                let (_, res) = TyLoweringContext::new(db, resolver).lower_ty_ext(type_ref);
+                res.map(|ty_ns| (ty_ns, path.segments().first()))
+            }
+            None => {
+                let (ty, remaining) =
+                    resolver.resolve_path_in_type_ns(db.upcast(), path.mod_path())?;
+                match remaining {
+                    Some(remaining) if remaining > 1 => None,
+                    _ => Some((ty, path.segments().get(1))),
+                }
+            }
+        }?;
+        let res = match ty {
             TypeNs::SelfType(it) => PathResolution::SelfType(it.into()),
             TypeNs::GenericParam(id) => PathResolution::TypeParam(TypeParam { id }),
             TypeNs::AdtSelfType(it) | TypeNs::AdtId(it) => {
@@ -476,7 +497,17 @@ fn resolve_hir_path_(
             TypeNs::TypeAliasId(it) => PathResolution::Def(TypeAlias::from(it).into()),
             TypeNs::BuiltinType(it) => PathResolution::Def(BuiltinType::from(it).into()),
             TypeNs::TraitId(it) => PathResolution::Def(Trait::from(it).into()),
-        })
+        };
+        match unresolved {
+            Some(unresolved) => res
+                .assoc_type_shorthand_candidates(db, |name, alias| {
+                    (name == unresolved.name).then(|| alias)
+                })
+                .map(TypeAlias::from)
+                .map(Into::into)
+                .map(PathResolution::Def),
+            None => Some(res),
+        }
     };
 
     let body_owner = resolver.body_owner();