9 files changed, 212 insertions, 163 deletions

diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 41c99d227..44547197c 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -5,42 +5,49 @@
 
 use std::iter::successors;
 
-use hir_def::{lang_item::LangItemTarget, resolver::Resolver};
+use hir_def::lang_item::LangItemTarget;
 use hir_expand::name;
 use log::{info, warn};
+use ra_db::CrateId;
 
 use crate::{db::HirDatabase, Trait};
 
-use super::{traits::Solution, Canonical, Substs, Ty, TypeWalk};
+use super::{
+    traits::{InEnvironment, Solution},
+    Canonical, Substs, Ty, TypeWalk,
+};
 
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
 
 pub(crate) fn autoderef<'a>(
     db: &'a impl HirDatabase,
-    resolver: &'a Resolver,
-    ty: Canonical<Ty>,
+    krate: Option<CrateId>,
+    ty: InEnvironment<Canonical<Ty>>,
 ) -> impl Iterator<Item = Canonical<Ty>> + 'a {
-    successors(Some(ty), move |ty| deref(db, resolver, ty)).take(AUTODEREF_RECURSION_LIMIT)
+    let InEnvironment { value: ty, environment } = ty;
+    successors(Some(ty), move |ty| {
+        deref(db, krate?, InEnvironment { value: ty, environment: environment.clone() })
+    })
+    .take(AUTODEREF_RECURSION_LIMIT)
 }
 
 pub(crate) fn deref(
     db: &impl HirDatabase,
-    resolver: &Resolver,
-    ty: &Canonical<Ty>,
+    krate: CrateId,
+    ty: InEnvironment<&Canonical<Ty>>,
 ) -> Option<Canonical<Ty>> {
-    if let Some(derefed) = ty.value.builtin_deref() {
-        Some(Canonical { value: derefed, num_vars: ty.num_vars })
+    if let Some(derefed) = ty.value.value.builtin_deref() {
+        Some(Canonical { value: derefed, num_vars: ty.value.num_vars })
     } else {
-        deref_by_trait(db, resolver, ty)
+        deref_by_trait(db, krate, ty)
     }
 }
 
 fn deref_by_trait(
     db: &impl HirDatabase,
-    resolver: &Resolver,
-    ty: &Canonical<Ty>,
+    krate: CrateId,
+    ty: InEnvironment<&Canonical<Ty>>,
 ) -> Option<Canonical<Ty>> {
-    let krate = resolver.krate()?;
     let deref_trait = match db.lang_item(krate.into(), "deref".into())? {
         LangItemTarget::TraitId(t) => Trait::from(t),
         _ => return None,
@@ -56,10 +63,8 @@ fn deref_by_trait(
 
     // FIXME make the Canonical handling nicer
 
-    let env = super::lower::trait_env(db, resolver);
-
     let parameters = Substs::build_for_generics(&generic_params)
-        .push(ty.value.clone().shift_bound_vars(1))
+        .push(ty.value.value.clone().shift_bound_vars(1))
         .build();
 
     let projection = super::traits::ProjectionPredicate {
@@ -69,9 +74,9 @@ fn deref_by_trait(
 
     let obligation = super::Obligation::Projection(projection);
 
-    let in_env = super::traits::InEnvironment { value: obligation, environment: env };
+    let in_env = InEnvironment { value: obligation, environment: ty.environment };
 
-    let canonical = super::Canonical { num_vars: 1 + ty.num_vars, value: in_env };
+    let canonical = super::Canonical { num_vars: 1 + ty.value.num_vars, value: in_env };
 
     let solution = db.trait_solve(krate.into(), canonical)?;
 
@@ -89,14 +94,14 @@ fn deref_by_trait(
             // the case.
             for i in 1..vars.0.num_vars {
                 if vars.0.value[i] != Ty::Bound((i - 1) as u32) {
-                    warn!("complex solution for derefing {:?}: {:?}, ignoring", ty, solution);
+                    warn!("complex solution for derefing {:?}: {:?}, ignoring", ty.value, solution);
                     return None;
                 }
             }
             Some(Canonical { value: vars.0.value[0].clone(), num_vars: vars.0.num_vars })
         }
         Solution::Ambig(_) => {
-            info!("Ambiguous solution for derefing {:?}: {:?}", ty, solution);
+            info!("Ambiguous solution for derefing {:?}: {:?}", ty.value, solution);
             None
         }
     }
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index 2e744e5ec..6fd00d457 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -34,7 +34,6 @@ use ra_prof::profile;
 use test_utils::tested_by;
 
 use super::{
-    lower,
     traits::{Guidance, Obligation, ProjectionPredicate, Solution},
     ApplicationTy, InEnvironment, ProjectionTy, Substs, TraitEnvironment, TraitRef, Ty, TypableDef,
     TypeCtor, TypeWalk, Uncertain,
@@ -44,8 +43,7 @@ use crate::{
     db::HirDatabase,
     expr::{BindingAnnotation, Body, ExprId, PatId},
     ty::infer::diagnostics::InferenceDiagnostic,
-    Adt, AssocItem, DefWithBody, FloatTy, Function, HasBody, IntTy, Path, StructField, Trait,
-    VariantDef,
+    Adt, AssocItem, DefWithBody, FloatTy, Function, IntTy, Path, StructField, Trait, VariantDef,
 };
 
 macro_rules! ty_app {
@@ -126,6 +124,8 @@ pub struct InferenceResult {
     method_resolutions: FxHashMap<ExprId, Function>,
     /// For each field access expr, records the field it resolves to.
     field_resolutions: FxHashMap<ExprId, StructField>,
+    /// For each field in record literal, records the field it resolves to.
+    record_field_resolutions: FxHashMap<ExprId, StructField>,
     /// For each struct literal, records the variant it resolves to.
     variant_resolutions: FxHashMap<ExprOrPatId, VariantDef>,
     /// For each associated item record what it resolves to
@@ -143,6 +143,9 @@ impl InferenceResult {
     pub fn field_resolution(&self, expr: ExprId) -> Option<StructField> {
         self.field_resolutions.get(&expr).copied()
     }
+    pub fn record_field_resolution(&self, expr: ExprId) -> Option<StructField> {
+        self.record_field_resolutions.get(&expr).copied()
+    }
     pub fn variant_resolution_for_expr(&self, id: ExprId) -> Option<VariantDef> {
         self.variant_resolutions.get(&id.into()).copied()
     }
@@ -212,11 +215,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             var_unification_table: InPlaceUnificationTable::new(),
             obligations: Vec::default(),
             return_ty: Ty::Unknown, // set in collect_fn_signature
-            trait_env: lower::trait_env(db, &resolver),
+            trait_env: TraitEnvironment::lower(db, &resolver),
             coerce_unsized_map: Self::init_coerce_unsized_map(db, &resolver),
             db,
             owner,
-            body: owner.body(db),
+            body: db.body(owner.into()),
             resolver,
         }
     }
diff --git a/crates/ra_hir/src/ty/infer/coerce.rs b/crates/ra_hir/src/ty/infer/coerce.rs
index 4ea038d99..4b53bba73 100644
--- a/crates/ra_hir/src/ty/infer/coerce.rs
+++ b/crates/ra_hir/src/ty/infer/coerce.rs
@@ -14,7 +14,7 @@ use crate::{
     Adt, Mutability,
 };
 
-use super::{InferTy, InferenceContext, TypeVarValue};
+use super::{InEnvironment, InferTy, InferenceContext, TypeVarValue};
 
 impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     /// Unify two types, but may coerce the first one to the second one
@@ -245,14 +245,17 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 ty_app!(TypeCtor::Adt(Adt::Struct(struct1)), st1),
                 ty_app!(TypeCtor::Adt(Adt::Struct(struct2)), st2),
             ) if struct1 == struct2 => {
-                let fields = struct1.fields(self.db);
-                let (last_field, prev_fields) = fields.split_last()?;
+                let field_tys = self.db.field_types(struct1.id.into());
+                let struct_data = self.db.struct_data(struct1.id.0);
+
+                let mut fields = struct_data.variant_data.fields().iter();
+                let (last_field_id, _data) = fields.next_back()?;
 
                 // Get the generic parameter involved in the last field.
                 let unsize_generic_index = {
                     let mut index = None;
                     let mut multiple_param = false;
-                    last_field.ty(self.db).walk(&mut |ty| match ty {
+                    field_tys[last_field_id].walk(&mut |ty| match ty {
                         &Ty::Param { idx, .. } => {
                             if index.is_none() {
                                 index = Some(idx);
@@ -271,8 +274,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
                 // Check other fields do not involve it.
                 let mut multiple_used = false;
-                prev_fields.iter().for_each(|field| {
-                    field.ty(self.db).walk(&mut |ty| match ty {
+                fields.for_each(|(field_id, _data)| {
+                    field_tys[field_id].walk(&mut |ty| match ty {
                         &Ty::Param { idx, .. } if idx == unsize_generic_index => {
                             multiple_used = true
                         }
@@ -317,9 +320,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         let canonicalized = self.canonicalizer().canonicalize_ty(from_ty.clone());
         let to_ty = self.resolve_ty_shallow(&to_ty);
         // FIXME: Auto DerefMut
-        for derefed_ty in
-            autoderef::autoderef(self.db, &self.resolver.clone(), canonicalized.value.clone())
-        {
+        for derefed_ty in autoderef::autoderef(
+            self.db,
+            self.resolver.krate(),
+            InEnvironment {
+                value: canonicalized.value.clone(),
+                environment: self.trait_env.clone(),
+            },
+        ) {
             let derefed_ty = canonicalized.decanonicalize_ty(derefed_ty.value);
             match (&*self.resolve_ty_shallow(&derefed_ty), &*to_ty) {
                 // Stop when constructor matches.
diff --git a/crates/ra_hir/src/ty/infer/expr.rs b/crates/ra_hir/src/ty/infer/expr.rs
index 20a7e9352..1d6df2b7a 100644
--- a/crates/ra_hir/src/ty/infer/expr.rs
+++ b/crates/ra_hir/src/ty/infer/expr.rs
@@ -8,6 +8,7 @@ use hir_def::{
     generics::GenericParams,
     path::{GenericArg, GenericArgs},
     resolver::resolver_for_expr,
+    ContainerId, Lookup,
 };
 use hir_expand::name;
 
@@ -15,9 +16,9 @@ use crate::{
     db::HirDatabase,
     expr::{Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp},
     ty::{
-        autoderef, method_resolution, op, CallableDef, InferTy, IntTy, Mutability, Namespace,
-        Obligation, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor, TypeWalk,
-        Uncertain,
+        autoderef, method_resolution, op, traits::InEnvironment, CallableDef, InferTy, IntTy,
+        Mutability, Namespace, Obligation, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty,
+        TypeCtor, TypeWalk, Uncertain,
     },
     Adt, Name,
 };
@@ -214,19 +215,24 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 self.unify(&ty, &expected.ty);
 
                 let substs = ty.substs().unwrap_or_else(Substs::empty);
+                let field_types =
+                    def_id.map(|it| self.db.field_types(it.into())).unwrap_or_default();
                 for (field_idx, field) in fields.iter().enumerate() {
-                    let field_ty = def_id
-                        .and_then(|it| match it.field(self.db, &field.name) {
-                            Some(field) => Some(field),
-                            None => {
-                                self.push_diagnostic(InferenceDiagnostic::NoSuchField {
-                                    expr: tgt_expr,
-                                    field: field_idx,
-                                });
-                                None
-                            }
-                        })
-                        .map_or(Ty::Unknown, |field| field.ty(self.db))
+                    let field_def = def_id.and_then(|it| match it.field(self.db, &field.name) {
+                        Some(field) => Some(field),
+                        None => {
+                            self.push_diagnostic(InferenceDiagnostic::NoSuchField {
+                                expr: tgt_expr,
+                                field: field_idx,
+                            });
+                            None
+                        }
+                    });
+                    if let Some(field_def) = field_def {
+                        self.result.record_field_resolutions.insert(field.expr, field_def);
+                    }
+                    let field_ty = field_def
+                        .map_or(Ty::Unknown, |it| field_types[it.id].clone())
                         .subst(&substs);
                     self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty));
                 }
@@ -240,8 +246,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 let canonicalized = self.canonicalizer().canonicalize_ty(receiver_ty);
                 let ty = autoderef::autoderef(
                     self.db,
-                    &self.resolver.clone(),
-                    canonicalized.value.clone(),
+                    self.resolver.krate(),
+                    InEnvironment {
+                        value: canonicalized.value.clone(),
+                        environment: self.trait_env.clone(),
+                    },
                 )
                 .find_map(|derefed_ty| match canonicalized.decanonicalize_ty(derefed_ty.value) {
                     Ty::Apply(a_ty) => match a_ty.ctor {
@@ -250,7 +259,9 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                             .and_then(|idx| a_ty.parameters.0.get(idx).cloned()),
                         TypeCtor::Adt(Adt::Struct(s)) => s.field(self.db, name).map(|field| {
                             self.write_field_resolution(tgt_expr, field);
-                            field.ty(self.db).subst(&a_ty.parameters)
+                            self.db.field_types(s.id.into())[field.id]
+                                .clone()
+                                .subst(&a_ty.parameters)
                         }),
                         _ => None,
                     },
@@ -330,16 +341,25 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Expr::UnaryOp { expr, op } => {
                 let inner_ty = self.infer_expr(*expr, &Expectation::none());
                 match op {
-                    UnaryOp::Deref => {
-                        let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty);
-                        if let Some(derefed_ty) =
-                            autoderef::deref(self.db, &self.resolver, &canonicalized.value)
-                        {
-                            canonicalized.decanonicalize_ty(derefed_ty.value)
-                        } else {
-                            Ty::Unknown
+                    UnaryOp::Deref => match self.resolver.krate() {
+                        Some(krate) => {
+                            let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty);
+                            match autoderef::deref(
+                                self.db,
+                                krate,
+                                InEnvironment {
+                                    value: &canonicalized.value,
+                                    environment: self.trait_env.clone(),
+                                },
+                            ) {
+                                Some(derefed_ty) => {
+                                    canonicalized.decanonicalize_ty(derefed_ty.value)
+                                }
+                                None => Ty::Unknown,
+                            }
                         }
-                    }
+                        None => Ty::Unknown,
+                    },
                     UnaryOp::Neg => {
                         match &inner_ty {
                             Ty::Apply(a_ty) => match a_ty.ctor {
@@ -641,18 +661,21 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 }
                 // add obligation for trait implementation, if this is a trait method
                 match def {
-                    CallableDef::Function(f) => {
-                        if let Some(trait_) = f.parent_trait(self.db) {
+                    CallableDef::FunctionId(f) => {
+                        if let ContainerId::TraitId(trait_) = f.lookup(self.db).container {
                             // construct a TraitDef
                             let substs = a_ty.parameters.prefix(
                                 self.db
-                                    .generic_params(trait_.id.into())
+                                    .generic_params(trait_.into())
                                     .count_params_including_parent(),
                             );
-                            self.obligations.push(Obligation::Trait(TraitRef { trait_, substs }));
+                            self.obligations.push(Obligation::Trait(TraitRef {
+                                trait_: trait_.into(),
+                                substs,
+                            }));
                         }
                     }
-                    CallableDef::Struct(_) | CallableDef::EnumVariant(_) => {}
+                    CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {}
                 }
             }
         }
diff --git a/crates/ra_hir/src/ty/infer/pat.rs b/crates/ra_hir/src/ty/infer/pat.rs
index c125ddfbc..641d61e87 100644
--- a/crates/ra_hir/src/ty/infer/pat.rs
+++ b/crates/ra_hir/src/ty/infer/pat.rs
@@ -27,10 +27,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
         let substs = ty.substs().unwrap_or_else(Substs::empty);
 
+        let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default();
         for (i, &subpat) in subpats.iter().enumerate() {
             let expected_ty = def
                 .and_then(|d| d.field(self.db, &Name::new_tuple_field(i)))
-                .map_or(Ty::Unknown, |field| field.ty(self.db))
+                .map_or(Ty::Unknown, |field| field_tys[field.id].clone())
                 .subst(&substs);
             let expected_ty = self.normalize_associated_types_in(expected_ty);
             self.infer_pat(subpat, &expected_ty, default_bm);
@@ -56,10 +57,12 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
         let substs = ty.substs().unwrap_or_else(Substs::empty);
 
+        let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default();
         for subpat in subpats {
             let matching_field = def.and_then(|it| it.field(self.db, &subpat.name));
-            let expected_ty =
-                matching_field.map_or(Ty::Unknown, |field| field.ty(self.db)).subst(&substs);
+            let expected_ty = matching_field
+                .map_or(Ty::Unknown, |field| field_tys[field.id].clone())
+                .subst(&substs);
             let expected_ty = self.normalize_associated_types_in(expected_ty);
             self.infer_pat(subpat.pat, &expected_ty, default_bm);
         }
diff --git a/crates/ra_hir/src/ty/infer/path.rs b/crates/ra_hir/src/ty/infer/path.rs
index ee54d8217..6165eba4f 100644
--- a/crates/ra_hir/src/ty/infer/path.rs
+++ b/crates/ra_hir/src/ty/infer/path.rs
@@ -203,7 +203,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     Container::ImplBlock(_) => self.find_self_types(&def, ty.clone()),
                     Container::Trait(t) => {
                         // we're picking this method
-                        let trait_substs = Substs::build_for_def(self.db, t)
+                        let trait_substs = Substs::build_for_def(self.db, t.id)
                             .push(ty.clone())
                             .fill(std::iter::repeat_with(|| self.new_type_var()))
                             .build();
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index 2272510e8..27cfe00c1 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -14,12 +14,15 @@ use hir_def::{
     path::{GenericArg, PathSegment},
     resolver::{HasResolver, Resolver, TypeNs},
     type_ref::{TypeBound, TypeRef},
-    AdtId, GenericDefId,
+    AdtId, AstItemDef, EnumVariantId, FunctionId, GenericDefId, HasModule, LocalStructFieldId,
+    Lookup, StructId, VariantId,
 };
+use ra_arena::map::ArenaMap;
+use ra_db::CrateId;
 
 use super::{
-    FnSig, GenericPredicate, ProjectionPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor,
-    TypeWalk,
+    FnSig, GenericPredicate, ProjectionPredicate, ProjectionTy, Substs, TraitEnvironment, TraitRef,
+    Ty, TypeCtor, TypeWalk,
 };
 use crate::{
     db::HirDatabase,
@@ -28,8 +31,8 @@ use crate::{
         Adt,
     },
     util::make_mut_slice,
-    Const, Enum, EnumVariant, Function, GenericDef, ImplBlock, ModuleDef, Path, Static, Struct,
-    StructField, Trait, TypeAlias, Union, VariantDef,
+    Const, Enum, EnumVariant, Function, ImplBlock, ModuleDef, Path, Static, Struct, Trait,
+    TypeAlias, Union,
 };
 
 // FIXME: this is only really used in `type_for_def`, which contains a bunch of
@@ -260,8 +263,10 @@ impl Ty {
         let traits = traits_from_env.flat_map(|t| t.all_super_traits(db));
         for t in traits {
             if let Some(associated_ty) = t.associated_type_by_name(db, &segment.name) {
-                let substs =
-                    Substs::build_for_def(db, t).push(self_ty.clone()).fill_with_unknown().build();
+                let substs = Substs::build_for_def(db, t.id)
+                    .push(self_ty.clone())
+                    .fill_with_unknown()
+                    .build();
                 // FIXME handle type parameters on the segment
                 return Ty::Projection(ProjectionTy { associated_ty, parameters: substs });
             }
@@ -286,11 +291,11 @@ impl Ty {
         segment: &PathSegment,
         resolved: TypableDef,
     ) -> Substs {
-        let def_generic: Option<GenericDef> = match resolved {
-            TypableDef::Function(func) => Some(func.into()),
+        let def_generic: Option<GenericDefId> = match resolved {
+            TypableDef::Function(func) => Some(func.id.into()),
             TypableDef::Adt(adt) => Some(adt.into()),
-            TypableDef::EnumVariant(var) => Some(var.parent_enum(db).into()),
-            TypableDef::TypeAlias(t) => Some(t.into()),
+            TypableDef::EnumVariant(var) => Some(var.parent_enum(db).id.into()),
+            TypableDef::TypeAlias(t) => Some(t.id.into()),
             TypableDef::Const(_) | TypableDef::Static(_) | TypableDef::BuiltinType(_) => None,
         };
         substs_from_path_segment(db, resolver, segment, def_generic, false)
@@ -337,7 +342,7 @@ pub(super) fn substs_from_path_segment(
     db: &impl HirDatabase,
     resolver: &Resolver,
     segment: &PathSegment,
-    def_generic: Option<GenericDef>,
+    def_generic: Option<GenericDefId>,
     add_self_param: bool,
 ) -> Substs {
     let mut substs = Vec::new();
@@ -375,7 +380,7 @@ pub(super) fn substs_from_path_segment(
 
     // handle defaults
     if let Some(def_generic) = def_generic {
-        let default_substs = db.generic_defaults(def_generic);
+        let default_substs = db.generic_defaults(def_generic.into());
         assert_eq!(substs.len(), default_substs.len());
 
         for (i, default_ty) in default_substs.iter().enumerate() {
@@ -438,7 +443,7 @@ impl TraitRef {
     ) -> Substs {
         let has_self_param =
             segment.args_and_bindings.as_ref().map(|a| a.has_self_type).unwrap_or(false);
-        substs_from_path_segment(db, resolver, segment, Some(resolved.into()), !has_self_param)
+        substs_from_path_segment(db, resolver, segment, Some(resolved.id.into()), !has_self_param)
     }
 
     pub(crate) fn for_trait(db: &impl HirDatabase, trait_: Trait) -> TraitRef {
@@ -543,22 +548,29 @@ pub(crate) fn type_for_def(db: &impl HirDatabase, def: TypableDef, ns: Namespace
 /// Build the signature of a callable item (function, struct or enum variant).
 pub(crate) fn callable_item_sig(db: &impl HirDatabase, def: CallableDef) -> FnSig {
     match def {
-        CallableDef::Function(f) => fn_sig_for_fn(db, f),
-        CallableDef::Struct(s) => fn_sig_for_struct_constructor(db, s),
-        CallableDef::EnumVariant(e) => fn_sig_for_enum_variant_constructor(db, e),
+        CallableDef::FunctionId(f) => fn_sig_for_fn(db, f),
+        CallableDef::StructId(s) => fn_sig_for_struct_constructor(db, s),
+        CallableDef::EnumVariantId(e) => fn_sig_for_enum_variant_constructor(db, e),
     }
 }
 
-/// Build the type of a specific field of a struct or enum variant.
-pub(crate) fn type_for_field(db: &impl HirDatabase, field: StructField) -> Ty {
-    let parent_def = field.parent_def(db);
-    let resolver = match parent_def {
-        VariantDef::Struct(it) => it.id.resolver(db),
-        VariantDef::EnumVariant(it) => it.parent.id.resolver(db),
+/// Build the type of all specific fields of a struct or enum variant.
+pub(crate) fn field_types_query(
+    db: &impl HirDatabase,
+    variant_id: VariantId,
+) -> Arc<ArenaMap<LocalStructFieldId, Ty>> {
+    let (resolver, var_data) = match variant_id {
+        VariantId::StructId(it) => (it.resolver(db), db.struct_data(it.0).variant_data.clone()),
+        VariantId::EnumVariantId(it) => (
+            it.parent.resolver(db),
+            db.enum_data(it.parent).variants[it.local_id].variant_data.clone(),
+        ),
     };
-    let var_data = parent_def.variant_data(db);
-    let type_ref = &var_data.fields().unwrap()[field.id].type_ref;
-    Ty::from_hir(db, &resolver, type_ref)
+    let mut res = ArenaMap::default();
+    for (field_id, field_data) in var_data.fields().iter() {
+        res.insert(field_id, Ty::from_hir(db, &resolver, &field_data.type_ref))
+    }
+    Arc::new(res)
 }
 
 /// This query exists only to be used when resolving short-hand associated types
@@ -571,10 +583,10 @@ pub(crate) fn type_for_field(db: &impl HirDatabase, field: StructField) -> Ty {
 /// these are fine: `T: Foo<U::Item>, U: Foo<()>`.
 pub(crate) fn generic_predicates_for_param_query(
     db: &impl HirDatabase,
-    def: GenericDef,
+    def: GenericDefId,
     param_idx: u32,
 ) -> Arc<[GenericPredicate]> {
-    let resolver = GenericDefId::from(def).resolver(db);
+    let resolver = def.resolver(db);
     resolver
         .where_predicates_in_scope()
         // we have to filter out all other predicates *first*, before attempting to lower them
@@ -583,24 +595,23 @@ pub(crate) fn generic_predicates_for_param_query(
         .collect()
 }
 
-pub(crate) fn trait_env(
-    db: &impl HirDatabase,
-    resolver: &Resolver,
-) -> Arc<super::TraitEnvironment> {
-    let predicates = resolver
-        .where_predicates_in_scope()
-        .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
-        .collect::<Vec<_>>();
+impl TraitEnvironment {
+    pub(crate) fn lower(db: &impl HirDatabase, resolver: &Resolver) -> Arc<TraitEnvironment> {
+        let predicates = resolver
+            .where_predicates_in_scope()
+            .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
+            .collect::<Vec<_>>();
 
-    Arc::new(super::TraitEnvironment { predicates })
+        Arc::new(TraitEnvironment { predicates })
+    }
 }
 
 /// Resolve the where clause(s) of an item with generics.
 pub(crate) fn generic_predicates_query(
     db: &impl HirDatabase,
-    def: GenericDef,
+    def: GenericDefId,
 ) -> Arc<[GenericPredicate]> {
-    let resolver = GenericDefId::from(def).resolver(db);
+    let resolver = def.resolver(db);
     resolver
         .where_predicates_in_scope()
         .flat_map(|pred| GenericPredicate::from_where_predicate(db, &resolver, pred))
@@ -608,8 +619,8 @@ pub(crate) fn generic_predicates_query(
 }
 
 /// Resolve the default type params from generics
-pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDef) -> Substs {
-    let resolver = GenericDefId::from(def).resolver(db);
+pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDefId) -> Substs {
+    let resolver = def.resolver(db);
     let generic_params = db.generic_params(def.into());
 
     let defaults = generic_params
@@ -621,9 +632,9 @@ pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDef) ->
     Substs(defaults)
 }
 
-fn fn_sig_for_fn(db: &impl HirDatabase, def: Function) -> FnSig {
-    let data = db.function_data(def.id);
-    let resolver = def.id.resolver(db);
+fn fn_sig_for_fn(db: &impl HirDatabase, def: FunctionId) -> FnSig {
+    let data = db.function_data(def);
+    let resolver = def.resolver(db);
     let params = data.params.iter().map(|tr| Ty::from_hir(db, &resolver, tr)).collect::<Vec<_>>();
     let ret = Ty::from_hir(db, &resolver, &data.ret_type);
     FnSig::from_params_and_return(params, ret)
@@ -634,7 +645,7 @@ fn fn_sig_for_fn(db: &impl HirDatabase, def: Function) -> FnSig {
 fn type_for_fn(db: &impl HirDatabase, def: Function) -> Ty {
     let generics = db.generic_params(def.id.into());
     let substs = Substs::identity(&generics);
-    Ty::apply(TypeCtor::FnDef(def.into()), substs)
+    Ty::apply(TypeCtor::FnDef(def.id.into()), substs)
 }
 
 /// Build the declared type of a const.
@@ -694,58 +705,53 @@ impl From<Option<BuiltinFloat>> for Uncertain<FloatTy> {
     }
 }
 
-fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: Struct) -> FnSig {
-    let struct_data = db.struct_data(def.id.into());
-    let fields = match struct_data.variant_data.fields() {
-        Some(fields) => fields,
-        None => panic!("fn_sig_for_struct_constructor called on unit struct"),
-    };
-    let resolver = def.id.resolver(db);
+fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> FnSig {
+    let struct_data = db.struct_data(def.into());
+    let fields = struct_data.variant_data.fields();
+    let resolver = def.resolver(db);
     let params = fields
         .iter()
         .map(|(_, field)| Ty::from_hir(db, &resolver, &field.type_ref))
         .collect::<Vec<_>>();
-    let ret = type_for_adt(db, def);
+    let ret = type_for_adt(db, Struct::from(def));
     FnSig::from_params_and_return(params, ret)
 }
 
 /// Build the type of a tuple struct constructor.
 fn type_for_struct_constructor(db: &impl HirDatabase, def: Struct) -> Ty {
     let struct_data = db.struct_data(def.id.into());
-    if struct_data.variant_data.fields().is_none() {
+    if struct_data.variant_data.is_unit() {
         return type_for_adt(db, def); // Unit struct
     }
     let generics = db.generic_params(def.id.into());
     let substs = Substs::identity(&generics);
-    Ty::apply(TypeCtor::FnDef(def.into()), substs)
+    Ty::apply(TypeCtor::FnDef(def.id.into()), substs)
 }
 
-fn fn_sig_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariant) -> FnSig {
-    let var_data = def.variant_data(db);
-    let fields = match var_data.fields() {
-        Some(fields) => fields,
-        None => panic!("fn_sig_for_enum_variant_constructor called for unit variant"),
-    };
-    let resolver = def.parent.id.resolver(db);
+fn fn_sig_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariantId) -> FnSig {
+    let enum_data = db.enum_data(def.parent);
+    let var_data = &enum_data.variants[def.local_id];
+    let fields = var_data.variant_data.fields();
+    let resolver = def.parent.resolver(db);
     let params = fields
         .iter()
         .map(|(_, field)| Ty::from_hir(db, &resolver, &field.type_ref))
         .collect::<Vec<_>>();
-    let generics = db.generic_params(def.parent_enum(db).id.into());
+    let generics = db.generic_params(def.parent.into());
     let substs = Substs::identity(&generics);
-    let ret = type_for_adt(db, def.parent_enum(db)).subst(&substs);
+    let ret = type_for_adt(db, Enum::from(def.parent)).subst(&substs);
     FnSig::from_params_and_return(params, ret)
 }
 
 /// Build the type of a tuple enum variant constructor.
 fn type_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariant) -> Ty {
     let var_data = def.variant_data(db);
-    if var_data.fields().is_none() {
+    if var_data.is_unit() {
         return type_for_adt(db, def.parent_enum(db)); // Unit variant
     }
     let generics = db.generic_params(def.parent_enum(db).id.into());
     let substs = Substs::identity(&generics);
-    Ty::apply(TypeCtor::FnDef(def.into()), substs)
+    Ty::apply(TypeCtor::FnDef(EnumVariantId::from(def).into()), substs)
 }
 
 fn type_for_adt(db: &impl HirDatabase, adt: impl Into<Adt>) -> Ty {
@@ -802,28 +808,28 @@ impl From<ModuleDef> for Option<TypableDef> {
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub enum CallableDef {
-    Function(Function),
-    Struct(Struct),
-    EnumVariant(EnumVariant),
+    FunctionId(FunctionId),
+    StructId(StructId),
+    EnumVariantId(EnumVariantId),
 }
-impl_froms!(CallableDef: Function, Struct, EnumVariant);
+impl_froms!(CallableDef: FunctionId, StructId, EnumVariantId);
 
 impl CallableDef {
-    pub fn krate(self, db: &impl HirDatabase) -> Option<crate::Crate> {
+    pub fn krate(self, db: &impl HirDatabase) -> CrateId {
         match self {
-            CallableDef::Function(f) => f.krate(db),
-            CallableDef::Struct(s) => s.krate(db),
-            CallableDef::EnumVariant(e) => e.parent_enum(db).krate(db),
+            CallableDef::FunctionId(f) => f.lookup(db).module(db).krate,
+            CallableDef::StructId(s) => s.0.module(db).krate,
+            CallableDef::EnumVariantId(e) => e.parent.module(db).krate,
         }
     }
 }
 
-impl From<CallableDef> for GenericDef {
-    fn from(def: CallableDef) -> GenericDef {
+impl From<CallableDef> for GenericDefId {
+    fn from(def: CallableDef) -> GenericDefId {
         match def {
-            CallableDef::Function(f) => f.into(),
-            CallableDef::Struct(s) => s.into(),
-            CallableDef::EnumVariant(e) => e.into(),
+            CallableDef::FunctionId(f) => f.into(),
+            CallableDef::StructId(s) => s.into(),
+            CallableDef::EnumVariantId(e) => e.into(),
         }
     }
 }
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index caa5f5f74..c5ab690eb 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -15,7 +15,7 @@ use crate::{
     AssocItem, Crate, Function, ImplBlock, Module, Mutability, Name, Trait,
 };
 
-use super::{autoderef, lower, Canonical, InEnvironment, TraitEnvironment, TraitRef};
+use super::{autoderef, Canonical, InEnvironment, TraitEnvironment, TraitRef};
 
 /// This is used as a key for indexing impls.
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
@@ -179,8 +179,9 @@ pub(crate) fn iterate_method_candidates<T>(
             // Also note that when we've got a receiver like &S, even if the method we
             // find in the end takes &self, we still do the autoderef step (just as
             // rustc does an autoderef and then autoref again).
-
-            for derefed_ty in autoderef::autoderef(db, resolver, ty.clone()) {
+            let environment = TraitEnvironment::lower(db, resolver);
+            let ty = InEnvironment { value: ty.clone(), environment };
+            for derefed_ty in autoderef::autoderef(db, resolver.krate(), ty) {
                 if let Some(result) = iterate_inherent_methods(
                     &derefed_ty,
                     db,
@@ -230,7 +231,7 @@ fn iterate_trait_method_candidates<T>(
 ) -> Option<T> {
     let krate = resolver.krate()?;
     // FIXME: maybe put the trait_env behind a query (need to figure out good input parameters for that)
-    let env = lower::trait_env(db, resolver);
+    let env = TraitEnvironment::lower(db, resolver);
     // if ty is `impl Trait` or `dyn Trait`, the trait doesn't need to be in scope
     let inherent_trait = ty.value.inherent_trait().into_iter();
     // if we have `T: Trait` in the param env, the trait doesn't need to be in scope
@@ -324,7 +325,7 @@ pub(crate) fn implements_trait(
         // anyway, but currently Chalk doesn't implement `dyn/impl Trait` yet
         return true;
     }
-    let env = lower::trait_env(db, resolver);
+    let env = TraitEnvironment::lower(db, resolver);
     let goal = generic_implements_goal(db, env, trait_, ty.clone());
     let solution = db.trait_solve(krate, goal);
 
@@ -364,7 +365,7 @@ fn generic_implements_goal(
     self_ty: Canonical<Ty>,
 ) -> Canonical<InEnvironment<super::Obligation>> {
     let num_vars = self_ty.num_vars;
-    let substs = super::Substs::build_for_def(db, trait_)
+    let substs = super::Substs::build_for_def(db, trait_.id)
         .push(self_ty.value)
         .fill_with_bound_vars(num_vars as u32)
         .build();
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 9efdc53c4..0272dd9ae 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -9,7 +9,7 @@ use chalk_ir::{
 };
 use chalk_rust_ir::{AssociatedTyDatum, AssociatedTyValue, ImplDatum, StructDatum, TraitDatum};
 
-use hir_def::lang_item::LangItemTarget;
+use hir_def::{lang_item::LangItemTarget, GenericDefId};
 use hir_expand::name;
 
 use ra_db::salsa::{InternId, InternKey};
@@ -19,7 +19,7 @@ use crate::{
     db::HirDatabase,
     ty::display::HirDisplay,
     ty::{ApplicationTy, GenericPredicate, ProjectionTy, Substs, TraitRef, Ty, TypeCtor, TypeWalk},
-    Crate, GenericDef, HasBody, ImplBlock, Trait, TypeAlias,
+    Crate, ImplBlock, Trait, TypeAlias,
 };
 
 /// This represents a trait whose name we could not resolve.
@@ -402,7 +402,7 @@ fn make_binders<T>(value: T, num_vars: usize) -> chalk_ir::Binders<T> {
 
 fn convert_where_clauses(
     db: &impl HirDatabase,
-    def: GenericDef,
+    def: GenericDefId,
     substs: &Substs,
 ) -> Vec<chalk_ir::QuantifiedWhereClause<ChalkIr>> {
     let generic_predicates = db.generic_predicates(def);
@@ -561,7 +561,7 @@ pub(crate) fn trait_datum_query(
         marker: false,
         fundamental: false,
     };
-    let where_clauses = convert_where_clauses(db, trait_.into(), &bound_vars);
+    let where_clauses = convert_where_clauses(db, trait_.id.into(), &bound_vars);
     let associated_ty_ids = trait_
         .items(db)
         .into_iter()
@@ -643,7 +643,7 @@ fn impl_block_datum(
     } else {
         chalk_rust_ir::ImplType::External
     };
-    let where_clauses = convert_where_clauses(db, impl_block.into(), &bound_vars);
+    let where_clauses = convert_where_clauses(db, impl_block.id.into(), &bound_vars);
     let negative = impl_block.is_negative(db);
     debug!(
         "impl {:?}: {}{} where {:?}",
@@ -715,7 +715,7 @@ fn closure_fn_trait_impl_datum(
     let fn_once_trait = get_fn_trait(db, krate, super::FnTrait::FnOnce)?;
     fn_once_trait.associated_type_by_name(db, &name::OUTPUT_TYPE)?;
 
-    let num_args: u16 = match &data.def.body(db)[data.expr] {
+    let num_args: u16 = match &db.body(data.def.into())[data.expr] {
         crate::expr::Expr::Lambda { args, .. } => args.len() as u16,
         _ => {
             log::warn!("closure for closure type {:?} not found", data);
@@ -736,7 +736,7 @@ fn closure_fn_trait_impl_datum(
 
     let trait_ref = TraitRef {
         trait_,
-        substs: Substs::build_for_def(db, trait_).push(self_ty).push(arg_ty).build(),
+        substs: Substs::build_for_def(db, trait_.id).push(self_ty).push(arg_ty).build(),
     };
 
     let output_ty_id = AssocTyValue::ClosureFnTraitImplOutput(data.clone()).to_chalk(db);
@@ -805,7 +805,7 @@ fn closure_fn_trait_output_assoc_ty_value(
 ) -> Arc<AssociatedTyValue<ChalkIr>> {
     let impl_id = Impl::ClosureFnTraitImpl(data.clone()).to_chalk(db);
 
-    let num_args: u16 = match &data.def.body(db)[data.expr] {
+    let num_args: u16 = match &db.body(data.def.into())[data.expr] {
         crate::expr::Expr::Lambda { args, .. } => args.len() as u16,
         _ => {
             log::warn!("closure for closure type {:?} not found", data);