5 files changed, 40 insertions, 46 deletions

diff --git a/crates/ra_hir/src/ty.rs b/crates/ra_hir/src/ty.rs
index 8a184de71..388530f31 100644
--- a/crates/ra_hir/src/ty.rs
+++ b/crates/ra_hir/src/ty.rs
@@ -19,13 +19,13 @@ use std::{fmt, iter, mem};
 
 use hir_def::{
     generics::GenericParams, AdtId, ContainerId, DefWithBodyId, GenericDefId, HasModule, Lookup,
-    TypeAliasId,
+    TraitId, TypeAliasId,
 };
 use ra_db::{impl_intern_key, salsa};
 
 use crate::{
     db::HirDatabase, expr::ExprId, util::make_mut_slice, Adt, Crate, FloatTy, IntTy, Mutability,
-    Name, Trait, TypeAlias, Uncertain,
+    Name, Trait, Uncertain,
 };
 use display::{HirDisplay, HirFormatter};
 
@@ -218,18 +218,19 @@ pub struct ApplicationTy {
 /// trait and all its parameters are fully known.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct ProjectionTy {
-    pub associated_ty: TypeAlias,
+    pub associated_ty: TypeAliasId,
     pub parameters: Substs,
 }
 
 impl ProjectionTy {
     pub fn trait_ref(&self, db: &impl HirDatabase) -> TraitRef {
-        TraitRef {
-            trait_: self
-                .associated_ty
-                .parent_trait(db)
-                .expect("projection ty without parent trait"),
-            substs: self.parameters.clone(),
+        TraitRef { trait_: self.trait_(db).into(), substs: self.parameters.clone() }
+    }
+
+    fn trait_(&self, db: &impl HirDatabase) -> TraitId {
+        match self.associated_ty.lookup(db).container {
+            ContainerId::TraitId(it) => it,
+            _ => panic!("projection ty without parent trait"),
         }
     }
 }
@@ -933,18 +934,15 @@ impl HirDisplay for ProjectionTy {
             return write!(f, "…");
         }
 
-        let trait_name = self
-            .associated_ty
-            .parent_trait(f.db)
-            .and_then(|t| t.name(f.db))
-            .unwrap_or_else(Name::missing);
+        let trait_name =
+            f.db.trait_data(self.trait_(f.db)).name.clone().unwrap_or_else(Name::missing);
         write!(f, "<{} as {}", self.parameters[0].display(f.db), trait_name,)?;
         if self.parameters.len() > 1 {
             write!(f, "<")?;
             f.write_joined(&self.parameters[1..], ", ")?;
             write!(f, ">")?;
         }
-        write!(f, ">::{}", self.associated_ty.name(f.db))?;
+        write!(f, ">::{}", f.db.type_alias_data(self.associated_ty).name)?;
         Ok(())
     }
 }
@@ -1007,7 +1005,10 @@ impl HirDisplay for Ty {
                                 write!(f, "<")?;
                                 angle_open = true;
                             }
-                            let name = projection_pred.projection_ty.associated_ty.name(f.db);
+                            let name =
+                                f.db.type_alias_data(projection_pred.projection_ty.associated_ty)
+                                    .name
+                                    .clone();
                             write!(f, "{} = ", name)?;
                             projection_pred.ty.hir_fmt(f)?;
                         }
@@ -1083,7 +1084,7 @@ impl HirDisplay for GenericPredicate {
                 write!(
                     f,
                     ">::{} = {}",
-                    projection_pred.projection_ty.associated_ty.name(f.db),
+                    f.db.type_alias_data(projection_pred.projection_ty.associated_ty).name,
                     projection_pred.ty.display(f.db)
                 )?;
             }
diff --git a/crates/ra_hir/src/ty/autoderef.rs b/crates/ra_hir/src/ty/autoderef.rs
index 44547197c..9e7593b8b 100644
--- a/crates/ra_hir/src/ty/autoderef.rs
+++ b/crates/ra_hir/src/ty/autoderef.rs
@@ -69,7 +69,7 @@ fn deref_by_trait(
 
     let projection = super::traits::ProjectionPredicate {
         ty: Ty::Bound(0),
-        projection_ty: super::ProjectionTy { associated_ty: target, parameters },
+        projection_ty: super::ProjectionTy { associated_ty: target.id, parameters },
     };
 
     let obligation = super::Obligation::Projection(projection);
diff --git a/crates/ra_hir/src/ty/infer/expr.rs b/crates/ra_hir/src/ty/infer/expr.rs
index b581d192f..316cdc880 100644
--- a/crates/ra_hir/src/ty/infer/expr.rs
+++ b/crates/ra_hir/src/ty/infer/expr.rs
@@ -101,7 +101,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                         let projection = ProjectionPredicate {
                             ty: pat_ty.clone(),
                             projection_ty: ProjectionTy {
-                                associated_ty: into_iter_item_alias,
+                                associated_ty: into_iter_item_alias.id,
                                 parameters: Substs::single(iterable_ty),
                             },
                         };
@@ -283,7 +283,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                         let projection = ProjectionPredicate {
                             ty: ty.clone(),
                             projection_ty: ProjectionTy {
-                                associated_ty: future_future_output_alias,
+                                associated_ty: future_future_output_alias.id,
                                 parameters: Substs::single(inner_ty),
                             },
                         };
@@ -302,7 +302,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                         let projection = ProjectionPredicate {
                             ty: ty.clone(),
                             projection_ty: ProjectionTy {
-                                associated_ty: ops_try_ok_alias,
+                                associated_ty: ops_try_ok_alias.id,
                                 parameters: Substs::single(inner_ty),
                             },
                         };
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index eb51d31bd..d7d4bb0d6 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -176,7 +176,7 @@ impl Ty {
                         Some(associated_ty) => {
                             // FIXME handle type parameters on the segment
                             Ty::Projection(ProjectionTy {
-                                associated_ty,
+                                associated_ty: associated_ty.id,
                                 parameters: trait_ref.substs,
                             })
                         }
@@ -268,7 +268,10 @@ impl Ty {
                     .fill_with_unknown()
                     .build();
                 // FIXME handle type parameters on the segment
-                return Ty::Projection(ProjectionTy { associated_ty, parameters: substs });
+                return Ty::Projection(ProjectionTy {
+                    associated_ty: associated_ty.id,
+                    parameters: substs,
+                });
             }
         }
         Ty::Unknown
@@ -508,7 +511,7 @@ fn assoc_type_bindings_from_type_bound<'a>(
             let associated_ty =
                 match trait_ref.trait_.associated_type_by_name_including_super_traits(db, &name) {
                     None => return GenericPredicate::Error,
-                    Some(t) => t,
+                    Some(t) => t.id,
                 };
             let projection_ty =
                 ProjectionTy { associated_ty, parameters: trait_ref.substs.clone() };
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index fd2f1b174..06388a3ce 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, GenericDefId, TypeAliasId};
+use hir_def::{lang_item::LangItemTarget, ContainerId, GenericDefId, Lookup, TypeAliasId};
 use hir_expand::name;
 
 use ra_db::salsa::{InternId, InternKey};
@@ -203,18 +203,6 @@ impl ToChalk for Impl {
     }
 }
 
-impl ToChalk for TypeAlias {
-    type Chalk = chalk_ir::TypeId;
-
-    fn to_chalk(self, _db: &impl HirDatabase) -> chalk_ir::TypeId {
-        chalk_ir::TypeId(id_to_chalk(self.id))
-    }
-
-    fn from_chalk(_db: &impl HirDatabase, type_alias_id: chalk_ir::TypeId) -> TypeAlias {
-        TypeAlias { id: id_from_chalk(type_alias_id.0) }
-    }
-}
-
 impl ToChalk for TypeAliasId {
     type Chalk = chalk_ir::TypeId;
 
@@ -516,21 +504,21 @@ pub(crate) fn associated_ty_data_query(
     id: TypeId,
 ) -> Arc<AssociatedTyDatum<ChalkIr>> {
     debug!("associated_ty_data {:?}", id);
-    let type_alias: TypeAlias = from_chalk(db, id);
-    let trait_ = match type_alias.container(db) {
-        Some(crate::Container::Trait(t)) => t,
+    let type_alias: TypeAliasId = from_chalk(db, id);
+    let trait_ = match type_alias.lookup(db).container {
+        ContainerId::TraitId(t) => t,
         _ => panic!("associated type not in trait"),
     };
-    let generic_params = db.generic_params(type_alias.id.into());
+    let generic_params = db.generic_params(type_alias.into());
     let bound_data = chalk_rust_ir::AssociatedTyDatumBound {
         // FIXME add bounds and where clauses
         bounds: vec![],
         where_clauses: vec![],
     };
     let datum = AssociatedTyDatum {
-        trait_id: trait_.to_chalk(db),
+        trait_id: Trait::from(trait_).to_chalk(db),
         id,
-        name: lalrpop_intern::intern(&type_alias.name(db).to_string()),
+        name: lalrpop_intern::intern(&db.type_alias_data(type_alias).name.to_string()),
         binders: make_binders(bound_data, generic_params.count_params_including_parent()),
     };
     Arc::new(datum)
@@ -578,7 +566,7 @@ pub(crate) fn trait_datum_query(
         .items(db)
         .into_iter()
         .filter_map(|trait_item| match trait_item {
-            crate::AssocItem::TypeAlias(type_alias) => Some(type_alias),
+            crate::AssocItem::TypeAlias(type_alias) => Some(type_alias.id),
             _ => None,
         })
         .map(|type_alias| type_alias.to_chalk(db))
@@ -797,7 +785,8 @@ fn type_alias_associated_ty_value(
         .trait_;
     let assoc_ty = trait_
         .associated_type_by_name(db, &type_alias.name(db))
-        .expect("assoc ty value should not exist"); // validated when building the impl data as well
+        .expect("assoc ty value should not exist") // validated when building the impl data as well
+        .id;
     let generic_params = db.generic_params(impl_block.id.into());
     let bound_vars = Substs::bound_vars(&generic_params);
     let ty = db.type_for_def(type_alias.into(), crate::ty::Namespace::Types).subst(&bound_vars);
@@ -832,7 +821,8 @@ fn closure_fn_trait_output_assoc_ty_value(
 
     let output_ty_id = fn_once_trait
         .associated_type_by_name(db, &name::OUTPUT_TYPE)
-        .expect("assoc ty value should not exist");
+        .expect("assoc ty value should not exist")
+        .id;
 
     let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty: output_ty.to_chalk(db) };