7 files changed, 43 insertions, 32 deletions

diff --git a/crates/hir_ty/src/autoderef.rs b/crates/hir_ty/src/autoderef.rs
index 7ca4af80e..c5890e24d 100644
--- a/crates/hir_ty/src/autoderef.rs
+++ b/crates/hir_ty/src/autoderef.rs
@@ -13,7 +13,7 @@ use log::{info, warn};
 
 use crate::{
     db::HirDatabase, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex,
-    InEnvironment, Interner, Solution, Ty, TyBuilder, TyKind,
+    InEnvironment, Interner, ProjectionTyExt, Solution, Ty, TyBuilder, TyKind,
 };
 
 const AUTODEREF_RECURSION_LIMIT: usize = 10;
diff --git a/crates/hir_ty/src/chalk_ext.rs b/crates/hir_ty/src/chalk_ext.rs
index b7463366b..0f4cb43e9 100644
--- a/crates/hir_ty/src/chalk_ext.rs
+++ b/crates/hir_ty/src/chalk_ext.rs
@@ -1,6 +1,11 @@
 //! Various extensions traits for Chalk types.
 
-use crate::{Interner, Ty, TyKind};
+use hir_def::{AssocContainerId, Lookup, TraitId};
+
+use crate::{
+    db::HirDatabase, from_assoc_type_id, to_chalk_trait_id, Interner, ProjectionTy, TraitRef, Ty,
+    TyKind,
+};
 
 pub trait TyExt {
     fn is_unit(&self) -> bool;
@@ -11,3 +16,24 @@ impl TyExt for Ty {
         matches!(self.kind(&Interner), TyKind::Tuple(0, _))
     }
 }
+
+pub trait ProjectionTyExt {
+    fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef;
+    fn trait_(&self, db: &dyn HirDatabase) -> TraitId;
+}
+
+impl ProjectionTyExt for ProjectionTy {
+    fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef {
+        TraitRef {
+            trait_id: to_chalk_trait_id(self.trait_(db)),
+            substitution: self.substitution.clone(),
+        }
+    }
+
+    fn trait_(&self, db: &dyn HirDatabase) -> TraitId {
+        match from_assoc_type_id(self.associated_ty_id).lookup(db.upcast()).container {
+            AssocContainerId::TraitId(it) => it,
+            _ => panic!("projection ty without parent trait"),
+        }
+    }
+}
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index 01c7ef91f..91d657ce2 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -22,7 +22,8 @@ use crate::{
     lt_from_placeholder_idx, primitive, to_assoc_type_id, traits::chalk::from_chalk,
     utils::generics, AdtId, AliasEq, AliasTy, CallableDefId, CallableSig, DomainGoal, GenericArg,
     ImplTraitId, Interner, Lifetime, LifetimeData, LifetimeOutlives, Mutability, OpaqueTy,
-    ProjectionTy, QuantifiedWhereClause, Scalar, TraitRef, Ty, TyExt, TyKind, WhereClause,
+    ProjectionTy, ProjectionTyExt, QuantifiedWhereClause, Scalar, TraitRef, Ty, TyExt, TyKind,
+    WhereClause,
 };
 
 pub struct HirFormatter<'a> {
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 6966d26e7..56a9365cb 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -22,8 +22,8 @@ use crate::{
     to_chalk_trait_id,
     traits::{chalk::from_chalk, FnTrait},
     utils::{generics, variant_data, Generics},
-    AdtId, Binders, CallableDefId, FnPointer, FnSig, InEnvironment, Interner, Rawness, Scalar,
-    Substitution, TraitRef, Ty, TyBuilder, TyKind,
+    AdtId, Binders, CallableDefId, FnPointer, FnSig, InEnvironment, Interner, ProjectionTyExt,
+    Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyKind,
 };
 
 use super::{
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index a3addc8e9..928dd76e5 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -43,13 +43,13 @@ use crate::{db::HirDatabase, display::HirDisplay, utils::generics};
 
 pub use autoderef::autoderef;
 pub use builder::TyBuilder;
-pub use chalk_ext::TyExt;
+pub use chalk_ext::{ProjectionTyExt, TyExt};
 pub use infer::{could_unify, InferenceResult, InferenceVar};
 pub use lower::{
     associated_type_shorthand_candidates, callable_item_sig, CallableDefId, ImplTraitLoweringMode,
     TyDefId, TyLoweringContext, ValueTyDefId,
 };
-pub use traits::TraitEnvironment;
+pub use traits::{chalk::Interner, TraitEnvironment};
 pub use types::*;
 pub use walk::TypeWalk;
 
@@ -57,8 +57,6 @@ pub use chalk_ir::{
     cast::Cast, AdtId, BoundVar, DebruijnIndex, Mutability, Safety, Scalar, TyVariableKind,
 };
 
-pub use crate::traits::chalk::Interner;
-
 pub type ForeignDefId = chalk_ir::ForeignDefId<Interner>;
 pub type AssocTypeId = chalk_ir::AssocTypeId<Interner>;
 pub type FnDefId = chalk_ir::FnDefId<Interner>;
@@ -76,26 +74,6 @@ pub type LifetimeOutlives = chalk_ir::LifetimeOutlives<Interner>;
 
 pub type ChalkTraitId = chalk_ir::TraitId<Interner>;
 
-impl ProjectionTy {
-    pub fn trait_ref(&self, db: &dyn HirDatabase) -> TraitRef {
-        TraitRef {
-            trait_id: to_chalk_trait_id(self.trait_(db)),
-            substitution: self.substitution.clone(),
-        }
-    }
-
-    pub fn self_type_parameter(&self, interner: &Interner) -> &Ty {
-        &self.substitution.interned()[0].assert_ty_ref(interner)
-    }
-
-    fn trait_(&self, db: &dyn HirDatabase) -> TraitId {
-        match from_assoc_type_id(self.associated_ty_id).lookup(db.upcast()).container {
-            AssocContainerId::TraitId(it) => it,
-            _ => panic!("projection ty without parent trait"),
-        }
-    }
-}
-
 pub type FnSig = chalk_ir::FnSig<Interner>;
 
 impl Substitution {
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index c3b148cab..9f10b889f 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -10,9 +10,9 @@ use base_db::salsa::InternKey;
 use hir_def::{GenericDefId, TypeAliasId};
 
 use crate::{
-    db::HirDatabase, primitive::UintTy, AliasTy, CallableDefId, Canonical, DomainGoal, FnPointer,
-    GenericArg, InEnvironment, OpaqueTy, ProjectionTy, QuantifiedWhereClause, Scalar, Substitution,
-    TraitRef, Ty, TypeWalk, WhereClause,
+    chalk_ext::ProjectionTyExt, db::HirDatabase, primitive::UintTy, AliasTy, CallableDefId,
+    Canonical, DomainGoal, FnPointer, GenericArg, InEnvironment, OpaqueTy, ProjectionTy,
+    QuantifiedWhereClause, Scalar, Substitution, TraitRef, Ty, TypeWalk, WhereClause,
 };
 
 use super::interner::*;
diff --git a/crates/hir_ty/src/types.rs b/crates/hir_ty/src/types.rs
index dc64e6e2b..bd89991dc 100644
--- a/crates/hir_ty/src/types.rs
+++ b/crates/hir_ty/src/types.rs
@@ -29,6 +29,12 @@ pub struct ProjectionTy {
     pub substitution: Substitution,
 }
 
+impl ProjectionTy {
+    pub fn self_type_parameter(&self, interner: &Interner) -> &Ty {
+        &self.substitution.interned()[0].assert_ty_ref(interner)
+    }
+}
+
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct DynTy {
     /// The unknown self type.