6 files changed, 32 insertions, 38 deletions

diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index ee15f4f52..9b1e2ad05 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -11,9 +11,9 @@ use hir_def::{
 use hir_expand::name::Name;
 
 use crate::{
-    db::HirDatabase, primitive, utils::generics, AdtId, AliasTy, CallableDefId, CallableSig,
-    GenericPredicate, Interner, Lifetime, Obligation, OpaqueTy, OpaqueTyId, ProjectionTy, Scalar,
-    Substs, TraitRef, Ty, TyKind,
+    db::HirDatabase, from_foreign_def_id, primitive, utils::generics, AdtId, AliasTy,
+    CallableDefId, CallableSig, GenericPredicate, Interner, Lifetime, Obligation, OpaqueTy,
+    OpaqueTyId, ProjectionTy, Scalar, Substs, TraitRef, Ty, TyKind,
 };
 
 pub struct HirFormatter<'a> {
@@ -491,7 +491,7 @@ impl HirDisplay for Ty {
                 }
             }
             TyKind::ForeignType(type_alias) => {
-                let type_alias = f.db.type_alias_data(*type_alias);
+                let type_alias = f.db.type_alias_data(from_foreign_def_id(*type_alias));
                 write!(f, "{}", type_alias.name)?;
             }
             TyKind::OpaqueType(opaque_ty_id, parameters) => {
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 2309db492..94cbb21ca 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -51,6 +51,8 @@ pub use chalk_ir::{AdtId, BoundVar, DebruijnIndex, Mutability, Scalar, TyVariabl
 
 pub use crate::traits::chalk::Interner;
 
+pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
+
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub enum Lifetime {
     Parameter(LifetimeParamId),
@@ -194,7 +196,7 @@ pub enum TyKind {
     Closure(DefWithBodyId, ExprId, Substs),
 
     /// Represents a foreign type declared in external blocks.
-    ForeignType(TypeAliasId),
+    ForeignType(ForeignDefId),
 
     /// A pointer to a function.  Written as `fn() -> i32`.
     ///
@@ -705,7 +707,7 @@ impl Ty {
             TyKind::Adt(AdtId(adt), ..) => Some(adt.into()),
             TyKind::FnDef(callable, ..) => Some(callable.into()),
             TyKind::AssociatedType(type_alias, ..) => Some(type_alias.into()),
-            TyKind::ForeignType(type_alias, ..) => Some(type_alias.into()),
+            TyKind::ForeignType(type_alias, ..) => Some(from_foreign_def_id(type_alias).into()),
             _ => None,
         }
     }
@@ -724,8 +726,10 @@ impl Ty {
             (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, ..))
-            | (TyKind::ForeignType(ty_id, ..), TyKind::ForeignType(ty_id2, ..)) => ty_id == ty_id2,
+            (TyKind::AssociatedType(ty_id, ..), TyKind::AssociatedType(ty_id2, ..)) => {
+                ty_id == ty_id2
+            }
+            (TyKind::ForeignType(ty_id, ..), TyKind::ForeignType(ty_id2, ..)) => ty_id == ty_id2,
             (TyKind::Closure(def, expr, _), TyKind::Closure(def2, expr2, _)) => {
                 expr == expr2 && def == def2
             }
@@ -1116,3 +1120,11 @@ pub struct ReturnTypeImplTraits {
 pub(crate) struct ReturnTypeImplTrait {
     pub(crate) bounds: Binders<Vec<GenericPredicate>>,
 }
+
+pub(crate) fn to_foreign_def_id(id: TypeAliasId) -> chalk_ir::ForeignDefId<Interner> {
+    chalk_ir::ForeignDefId(salsa::InternKey::as_intern_id(&id))
+}
+
+pub(crate) fn from_foreign_def_id(id: chalk_ir::ForeignDefId<Interner>) -> TypeAliasId {
+    salsa::InternKey::from_intern_id(id.0)
+}
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 9fe7e3dce..a35d7266d 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -1143,7 +1143,7 @@ fn type_for_type_alias(db: &dyn HirDatabase, t: TypeAliasId) -> Binders<Ty> {
     let ctx =
         TyLoweringContext::new(db, &resolver).with_type_param_mode(TypeParamLoweringMode::Variable);
     if db.type_alias_data(t).is_extern {
-        Binders::new(0, TyKind::ForeignType(t).intern(&Interner))
+        Binders::new(0, TyKind::ForeignType(crate::to_foreign_def_id(t)).intern(&Interner))
     } else {
         let substs = Substs::bound_vars(&generics, DebruijnIndex::INNERMOST);
         let type_ref = &db.type_alias_data(t).type_ref;
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index f9877e760..c7055bee5 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -9,7 +9,7 @@ use base_db::CrateId;
 use chalk_ir::Mutability;
 use hir_def::{
     lang_item::LangItemTarget, AssocContainerId, AssocItemId, FunctionId, GenericDefId, HasModule,
-    ImplId, Lookup, ModuleId, TraitId, TypeAliasId,
+    ImplId, Lookup, ModuleId, TraitId,
 };
 use hir_expand::name::Name;
 use rustc_hash::{FxHashMap, FxHashSet};
@@ -17,10 +17,11 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use crate::{
     autoderef,
     db::HirDatabase,
+    from_foreign_def_id,
     primitive::{self, FloatTy, IntTy, UintTy},
     utils::all_super_traits,
-    AdtId, Canonical, DebruijnIndex, FnPointer, FnSig, InEnvironment, Interner, Scalar, Substs,
-    TraitEnvironment, TraitRef, Ty, TyKind, TypeWalk,
+    AdtId, Canonical, DebruijnIndex, FnPointer, FnSig, ForeignDefId, InEnvironment, Interner,
+    Scalar, Substs, TraitEnvironment, TraitRef, Ty, TyKind, TypeWalk,
 };
 
 /// This is used as a key for indexing impls.
@@ -35,7 +36,7 @@ pub enum TyFingerprint {
     Adt(hir_def::AdtId),
     Dyn(TraitId),
     Tuple(usize),
-    ForeignType(TypeAliasId),
+    ForeignType(ForeignDefId),
     FnPtr(usize, FnSig),
 }
 
@@ -236,8 +237,10 @@ impl Ty {
             TyKind::Adt(AdtId(def_id), _) => {
                 return mod_to_crate_ids(def_id.module(db.upcast()));
             }
-            TyKind::ForeignType(type_alias_id) => {
-                return mod_to_crate_ids(type_alias_id.lookup(db.upcast()).module(db.upcast()));
+            TyKind::ForeignType(id) => {
+                return mod_to_crate_ids(
+                    from_foreign_def_id(*id).lookup(db.upcast()).module(db.upcast()),
+                );
             }
             TyKind::Scalar(Scalar::Bool) => lang_item_crate!("bool"),
             TyKind::Scalar(Scalar::Char) => lang_item_crate!("char"),
diff --git a/crates/hir_ty/src/traits/chalk/interner.rs b/crates/hir_ty/src/traits/chalk/interner.rs
index 54bd1c724..e891efb7b 100644
--- a/crates/hir_ty/src/traits/chalk/interner.rs
+++ b/crates/hir_ty/src/traits/chalk/interner.rs
@@ -12,7 +12,6 @@ pub struct Interner;
 
 pub(crate) type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
 pub(crate) type AssociatedTyDatum = chalk_solve::rust_ir::AssociatedTyDatum<Interner>;
-pub(crate) type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
 pub(crate) type TraitId = chalk_ir::TraitId<Interner>;
 pub(crate) type TraitDatum = chalk_solve::rust_ir::TraitDatum<Interner>;
 pub(crate) type AdtId = chalk_ir::AdtId<Interner>;
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index 44cfb9359..cf490f9c5 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -51,11 +51,7 @@ impl ToChalk for Ty {
                 chalk_ir::TyKind::OpaqueType(id, substitution).intern(&Interner)
             }
 
-            TyKind::ForeignType(type_alias) => {
-                let foreign_type = TypeAliasAsForeignType(type_alias);
-                let foreign_type_id = foreign_type.to_chalk(db);
-                chalk_ir::TyKind::Foreign(foreign_type_id).intern(&Interner)
-            }
+            TyKind::ForeignType(id) => chalk_ir::TyKind::Foreign(id).intern(&Interner),
 
             TyKind::Scalar(scalar) => chalk_ir::TyKind::Scalar(scalar).intern(&Interner),
 
@@ -217,9 +213,7 @@ impl ToChalk for Ty {
                 TyKind::Closure(def, expr, from_chalk(db, subst))
             }
 
-            chalk_ir::TyKind::Foreign(foreign_def_id) => {
-                TyKind::ForeignType(from_chalk::<TypeAliasAsForeignType, _>(db, foreign_def_id).0)
-            }
+            chalk_ir::TyKind::Foreign(foreign_def_id) => TyKind::ForeignType(foreign_def_id),
             chalk_ir::TyKind::Generator(_, _) => unimplemented!(), // FIXME
             chalk_ir::TyKind::GeneratorWitness(_, _) => unimplemented!(), // FIXME
         }
@@ -352,20 +346,6 @@ impl ToChalk for TypeAliasAsAssocType {
     }
 }
 
-pub(crate) struct TypeAliasAsForeignType(pub(crate) TypeAliasId);
-
-impl ToChalk for TypeAliasAsForeignType {
-    type Chalk = ForeignDefId;
-
-    fn to_chalk(self, _db: &dyn HirDatabase) -> ForeignDefId {
-        chalk_ir::ForeignDefId(self.0.as_intern_id())
-    }
-
-    fn from_chalk(_db: &dyn HirDatabase, foreign_def_id: ForeignDefId) -> TypeAliasAsForeignType {
-        TypeAliasAsForeignType(InternKey::from_intern_id(foreign_def_id.0))
-    }
-}
-
 pub(crate) struct TypeAliasAsValue(pub(crate) TypeAliasId);
 
 impl ToChalk for TypeAliasAsValue {